#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# MOTOROLA MICROPROCESSOR & MEMORY TECHNOLOGY GROUP
# M68000 Hi-Performance Microprocessor Division
# M68060 Software Package Production Release
#
# M68060 Software Package Copyright (C) 1993, 1994, 1995, 1996 Motorola Inc.
# All rights reserved.
#
# THE SOFTWARE is provided on an "AS IS" basis and without warranty.
# To the maximum extent permitted by applicable law,
# MOTOROLA DISCLAIMS ALL WARRANTIES WHETHER EXPRESS OR IMPLIED,
# INCLUDING IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS
# FOR A PARTICULAR PURPOSE and any warranty against infringement with
# regard to the SOFTWARE (INCLUDING ANY MODIFIED VERSIONS THEREOF)
# and any accompanying written materials.
#
# To the maximum extent permitted by applicable law,
# IN NO EVENT SHALL MOTOROLA BE LIABLE FOR ANY DAMAGES WHATSOEVER
# (INCLUDING WITHOUT LIMITATION, DAMAGES FOR LOSS OF BUSINESS PROFITS,
# BUSINESS INTERRUPTION, LOSS OF BUSINESS INFORMATION, OR OTHER PECUNIARY LOSS)
# ARISING OF THE USE OR INABILITY TO USE THE SOFTWARE.
#
# Motorola assumes no responsibility for the maintenance and support
# of the SOFTWARE.
#
# You are hereby granted a copyright license to use, modify, and distribute the
# SOFTWARE so long as this entire notice is retained without alteration
# in any modified and/or redistributed versions, and that such modified
# versions are clearly identified as such.
# No licenses are granted by implication, estoppel or otherwise under any
# patents or trademarks of Motorola, Inc.
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#
# freal.s:
# This file is appended to the top of the 060FPSP package
# and contains the entry points into the package. The user, in
# effect, branches to one of the branch table entries located
# after _060FPSP_TABLE.
# Also, subroutine stubs exist in this file (_fpsp_done for
# example) that are referenced by the FPSP package itself in order
# to call a given routine. The stub routine actually performs the
# callout. The FPSP code does a "bsr" to the stub routine. This
# extra layer of hierarchy adds a slight performance penalty but
# it makes the FPSP code easier to read and more mainatinable.
#
set _off_bsun, 0x00
set _off_snan, 0x04
set _off_operr, 0x08
set _off_ovfl, 0x0c
set _off_unfl, 0x10
set _off_dz, 0x14
set _off_inex, 0x18
set _off_fline, 0x1c
set _off_fpu_dis, 0x20
set _off_trap, 0x24
set _off_trace, 0x28
set _off_access, 0x2c
set _off_done, 0x30
set _off_imr, 0x40
set _off_dmr, 0x44
set _off_dmw, 0x48
set _off_irw, 0x4c
set _off_irl, 0x50
set _off_drb, 0x54
set _off_drw, 0x58
set _off_drl, 0x5c
set _off_dwb, 0x60
set _off_dww, 0x64
set _off_dwl, 0x68
# Here's the table of ENTRY POINTS for those linking the package.
bra.l _fpsp_snan
short 0x0000
bra.l _fpsp_operr
short 0x0000
bra.l _fpsp_ovfl
short 0x0000
bra.l _fpsp_unfl
short 0x0000
bra.l _fpsp_dz
short 0x0000
bra.l _fpsp_inex
short 0x0000
bra.l _fpsp_fline
short 0x0000
bra.l _fpsp_unsupp
short 0x0000
bra.l _fpsp_effadd
short 0x0000
#
# This file contains a set of define statements for constants
# in order to promote readability within the corecode itself.
#
set LOCAL_SIZE, 192 # stack frame size(bytes)
set LV, -LOCAL_SIZE # stack offset
set EXC_SR, 0x4 # stack status register
set EXC_PC, 0x6 # stack pc
set EXC_VOFF, 0xa # stacked vector offset
set EXC_EA, 0xc # stacked <ea>
set EXC_FP, 0x0 # frame pointer
set EXC_AREGS, -68 # offset of all address regs
set EXC_DREGS, -100 # offset of all data regs
set EXC_FPREGS, -36 # offset of all fp regs
set EXC_A7, EXC_AREGS+(7*4) # offset of saved a7
set OLD_A7, EXC_AREGS+(6*4) # extra copy of saved a7
set EXC_A6, EXC_AREGS+(6*4) # offset of saved a6
set EXC_A5, EXC_AREGS+(5*4)
set EXC_A4, EXC_AREGS+(4*4)
set EXC_A3, EXC_AREGS+(3*4)
set EXC_A2, EXC_AREGS+(2*4)
set EXC_A1, EXC_AREGS+(1*4)
set EXC_A0, EXC_AREGS+(0*4)
set EXC_D7, EXC_DREGS+(7*4)
set EXC_D6, EXC_DREGS+(6*4)
set EXC_D5, EXC_DREGS+(5*4)
set EXC_D4, EXC_DREGS+(4*4)
set EXC_D3, EXC_DREGS+(3*4)
set EXC_D2, EXC_DREGS+(2*4)
set EXC_D1, EXC_DREGS+(1*4)
set EXC_D0, EXC_DREGS+(0*4)
set EXC_FP0, EXC_FPREGS+(0*12) # offset of saved fp0
set EXC_FP1, EXC_FPREGS+(1*12) # offset of saved fp1
set EXC_FP2, EXC_FPREGS+(2*12) # offset of saved fp2 (not used)
set FP_SCR1, LV+80 # fp scratch 1
set FP_SCR1_EX, FP_SCR1+0
set FP_SCR1_SGN, FP_SCR1+2
set FP_SCR1_HI, FP_SCR1+4
set FP_SCR1_LO, FP_SCR1+8
set FP_SCR0, LV+68 # fp scratch 0
set FP_SCR0_EX, FP_SCR0+0
set FP_SCR0_SGN, FP_SCR0+2
set FP_SCR0_HI, FP_SCR0+4
set FP_SCR0_LO, FP_SCR0+8
set FP_DST, LV+56 # fp destination operand
set FP_DST_EX, FP_DST+0
set FP_DST_SGN, FP_DST+2
set FP_DST_HI, FP_DST+4
set FP_DST_LO, FP_DST+8
set FP_SRC, LV+44 # fp source operand
set FP_SRC_EX, FP_SRC+0
set FP_SRC_SGN, FP_SRC+2
set FP_SRC_HI, FP_SRC+4
set FP_SRC_LO, FP_SRC+8
set USER_FPIAR, LV+40 # FP instr address register
set USER_FPSR, LV+36 # FP status register
set FPSR_CC, USER_FPSR+0 # FPSR condition codes
set FPSR_QBYTE, USER_FPSR+1 # FPSR qoutient byte
set FPSR_EXCEPT, USER_FPSR+2 # FPSR exception status byte
set FPSR_AEXCEPT, USER_FPSR+3 # FPSR accrued exception byte
set USER_FPCR, LV+32 # FP control register
set FPCR_ENABLE, USER_FPCR+2 # FPCR exception enable
set FPCR_MODE, USER_FPCR+3 # FPCR rounding mode control
set L_SCR3, LV+28 # integer scratch 3
set L_SCR2, LV+24 # integer scratch 2
set L_SCR1, LV+20 # integer scratch 1
set STORE_FLG, LV+19 # flag: operand store (ie. not fcmp/ftst)
set EXC_TEMP2, LV+24 # temporary space
set EXC_TEMP, LV+16 # temporary space
set DTAG, LV+15 # destination operand type
set STAG, LV+14 # source operand type
set SPCOND_FLG, LV+10 # flag: special case (see below)
set EXC_CC, LV+8 # saved condition codes
set EXC_EXTWPTR, LV+4 # saved current PC (active)
set EXC_EXTWORD, LV+2 # saved extension word
set EXC_CMDREG, LV+2 # saved extension word
set EXC_OPWORD, LV+0 # saved operation word
################################
# Helpful macros
set FTEMP, 0 # offsets within an
set FTEMP_EX, 0 # extended precision
set FTEMP_SGN, 2 # value saved in memory.
set FTEMP_HI, 4
set FTEMP_LO, 8
set FTEMP_GRS, 12
set LOCAL, 0 # offsets within an
set LOCAL_EX, 0 # extended precision
set LOCAL_SGN, 2 # value saved in memory.
set LOCAL_HI, 4
set LOCAL_LO, 8
set LOCAL_GRS, 12
set DST, 0 # offsets within an
set DST_EX, 0 # extended precision
set DST_HI, 4 # value saved in memory.
set DST_LO, 8
set SRC, 0 # offsets within an
set SRC_EX, 0 # extended precision
set SRC_HI, 4 # value saved in memory.
set SRC_LO, 8
set SGL_LO, 0x3f81 # min sgl prec exponent
set SGL_HI, 0x407e # max sgl prec exponent
set DBL_LO, 0x3c01 # min dbl prec exponent
set DBL_HI, 0x43fe # max dbl prec exponent
set EXT_LO, 0x0 # min ext prec exponent
set EXT_HI, 0x7ffe # max ext prec exponent
set EXT_BIAS, 0x3fff # extended precision bias
set SGL_BIAS, 0x007f # single precision bias
set DBL_BIAS, 0x03ff # double precision bias
set NORM, 0x00 # operand type for STAG/DTAG
set ZERO, 0x01 # operand type for STAG/DTAG
set INF, 0x02 # operand type for STAG/DTAG
set QNAN, 0x03 # operand type for STAG/DTAG
set DENORM, 0x04 # operand type for STAG/DTAG
set SNAN, 0x05 # operand type for STAG/DTAG
set UNNORM, 0x06 # operand type for STAG/DTAG
##################
# FPSR/FPCR bits #
##################
set neg_bit, 0x3 # negative result
set z_bit, 0x2 # zero result
set inf_bit, 0x1 # infinite result
set nan_bit, 0x0 # NAN result
set q_sn_bit, 0x7 # sign bit of quotient byte
set bsun_bit, 7 # branch on unordered
set snan_bit, 6 # signalling NAN
set operr_bit, 5 # operand error
set ovfl_bit, 4 # overflow
set unfl_bit, 3 # underflow
set dz_bit, 2 # divide by zero
set inex2_bit, 1 # inexact result 2
set inex1_bit, 0 # inexact result 1
set aiop_bit, 7 # accrued inexact operation bit
set aovfl_bit, 6 # accrued overflow bit
set aunfl_bit, 5 # accrued underflow bit
set adz_bit, 4 # accrued dz bit
set ainex_bit, 3 # accrued inexact bit
#############################
# FPSR individual bit masks #
#############################
set neg_mask, 0x08000000 # negative bit mask (lw)
set inf_mask, 0x02000000 # infinity bit mask (lw)
set z_mask, 0x04000000 # zero bit mask (lw)
set nan_mask, 0x01000000 # nan bit mask (lw)
set neg_bmask, 0x08 # negative bit mask (byte)
set inf_bmask, 0x02 # infinity bit mask (byte)
set z_bmask, 0x04 # zero bit mask (byte)
set nan_bmask, 0x01 # nan bit mask (byte)
set bsun_mask, 0x00008000 # bsun exception mask
set snan_mask, 0x00004000 # snan exception mask
set operr_mask, 0x00002000 # operr exception mask
set ovfl_mask, 0x00001000 # overflow exception mask
set unfl_mask, 0x00000800 # underflow exception mask
set dz_mask, 0x00000400 # dz exception mask
set inex2_mask, 0x00000200 # inex2 exception mask
set inex1_mask, 0x00000100 # inex1 exception mask
set aiop_mask, 0x00000080 # accrued illegal operation
set aovfl_mask, 0x00000040 # accrued overflow
set aunfl_mask, 0x00000020 # accrued underflow
set adz_mask, 0x00000010 # accrued divide by zero
set ainex_mask, 0x00000008 # accrued inexact
######################################
# FPSR combinations used in the FPSP #
######################################
set dzinf_mask, inf_mask+dz_mask+adz_mask
set opnan_mask, nan_mask+operr_mask+aiop_mask
set nzi_mask, 0x01ffffff #clears N, Z, and I
set unfinx_mask, unfl_mask+inex2_mask+aunfl_mask+ainex_mask
set unf2inx_mask, unfl_mask+inex2_mask+ainex_mask
set ovfinx_mask, ovfl_mask+inex2_mask+aovfl_mask+ainex_mask
set inx1a_mask, inex1_mask+ainex_mask
set inx2a_mask, inex2_mask+ainex_mask
set snaniop_mask, nan_mask+snan_mask+aiop_mask
set snaniop2_mask, snan_mask+aiop_mask
set naniop_mask, nan_mask+aiop_mask
set neginf_mask, neg_mask+inf_mask
set infaiop_mask, inf_mask+aiop_mask
set negz_mask, neg_mask+z_mask
set opaop_mask, operr_mask+aiop_mask
set unfl_inx_mask, unfl_mask+aunfl_mask+ainex_mask
set ovfl_inx_mask, ovfl_mask+aovfl_mask+ainex_mask
#########
# misc. #
#########
set rnd_stky_bit, 29 # stky bit pos in longword
set sign_bit, 0x7 # sign bit
set signan_bit, 0x6 # signalling nan bit
set sgl_thresh, 0x3f81 # minimum sgl exponent
set dbl_thresh, 0x3c01 # minimum dbl exponent
set x_mode, 0x0 # extended precision
set s_mode, 0x4 # single precision
set d_mode, 0x8 # double precision
set rn_mode, 0x0 # round-to-nearest
set rz_mode, 0x1 # round-to-zero
set rm_mode, 0x2 # round-tp-minus-infinity
set rp_mode, 0x3 # round-to-plus-infinity
set mantissalen, 64 # length of mantissa in bits
set BYTE, 1 # len(byte) == 1 byte
set WORD, 2 # len(word) == 2 bytes
set LONG, 4 # len(longword) == 2 bytes
set BSUN_VEC, 0xc0 # bsun vector offset
set INEX_VEC, 0xc4 # inexact vector offset
set DZ_VEC, 0xc8 # dz vector offset
set UNFL_VEC, 0xcc # unfl vector offset
set OPERR_VEC, 0xd0 # operr vector offset
set OVFL_VEC, 0xd4 # ovfl vector offset
set SNAN_VEC, 0xd8 # snan vector offset
###########################
# SPecial CONDition FLaGs #
###########################
set ftrapcc_flg, 0x01 # flag bit: ftrapcc exception
set fbsun_flg, 0x02 # flag bit: bsun exception
set mia7_flg, 0x04 # flag bit: (a7)+ <ea>
set mda7_flg, 0x08 # flag bit: -(a7) <ea>
set fmovm_flg, 0x40 # flag bit: fmovm instruction
set immed_flg, 0x80 # flag bit: &<data> <ea>
set ftrapcc_bit, 0x0
set fbsun_bit, 0x1
set mia7_bit, 0x2
set mda7_bit, 0x3
set immed_bit, 0x7
##################################
# TRANSCENDENTAL "LAST-OP" FLAGS #
##################################
set FMUL_OP, 0x0 # fmul instr performed last
set FDIV_OP, 0x1 # fdiv performed last
set FADD_OP, 0x2 # fadd performed last
set FMOV_OP, 0x3 # fmov performed last
#############
# CONSTANTS #
#############
T1: long 0x40C62D38,0xD3D64634 # 16381 LOG2 LEAD
T2: long 0x3D6F90AE,0xB1E75CC7 # 16381 LOG2 TRAIL
PI: long 0x40000000,0xC90FDAA2,0x2168C235,0x00000000
PIBY2: long 0x3FFF0000,0xC90FDAA2,0x2168C235,0x00000000
TWOBYPI:
long 0x3FE45F30,0x6DC9C883
#########################################################################
# XDEF **************************************************************** #
# _fpsp_ovfl(): 060FPSP entry point for FP Overflow exception. #
# #
# This handler should be the first code executed upon taking the #
# FP Overflow exception in an operating system. #
# #
# XREF **************************************************************** #
# _imem_read_long() - read instruction longword #
# fix_skewed_ops() - adjust src operand in fsave frame #
# set_tag_x() - determine optype of src/dst operands #
# store_fpreg() - store opclass 0 or 2 result to FP regfile #
# unnorm_fix() - change UNNORM operands to NORM or ZERO #
# load_fpn2() - load dst operand from FP regfile #
# fout() - emulate an opclass 3 instruction #
# tbl_unsupp - add of table of emulation routines for opclass 0,2 #
# _fpsp_done() - "callout" for 060FPSP exit (all work done!) #
# _real_ovfl() - "callout" for Overflow exception enabled code #
# _real_inex() - "callout" for Inexact exception enabled code #
# _real_trace() - "callout" for Trace exception code #
# #
# INPUT *************************************************************** #
# - The system stack contains the FP Ovfl exception stack frame #
# - The fsave frame contains the source operand #
# #
# OUTPUT ************************************************************** #
# Overflow Exception enabled: #
# - The system stack is unchanged #
# - The fsave frame contains the adjusted src op for opclass 0,2 #
# Overflow Exception disabled: #
# - The system stack is unchanged #
# - The "exception present" flag in the fsave frame is cleared #
# #
# ALGORITHM *********************************************************** #
# On the 060, if an FP overflow is present as the result of any #
# instruction, the 060 will take an overflow exception whether the #
# exception is enabled or disabled in the FPCR. For the disabled case, #
# This handler emulates the instruction to determine what the correct #
# default result should be for the operation. This default result is #
# then stored in either the FP regfile, data regfile, or memory. #
# Finally, the handler exits through the "callout" _fpsp_done() #
# denoting that no exceptional conditions exist within the machine. #
# If the exception is enabled, then this handler must create the #
# exceptional operand and plave it in the fsave state frame, and store #
# the default result (only if the instruction is opclass 3). For #
# exceptions enabled, this handler must exit through the "callout" #
# _real_ovfl() so that the operating system enabled overflow handler #
# can handle this case. #
# Two other conditions exist. First, if overflow was disabled #
# but the inexact exception was enabled, this handler must exit #
# through the "callout" _real_inex() regardless of whether the result #
# was inexact. #
# Also, in the case of an opclass three instruction where #
# overflow was disabled and the trace exception was enabled, this #
# handler must exit through the "callout" _real_trace(). #
# #
#########################################################################
global _fpsp_ovfl
_fpsp_ovfl:
#$# sub.l &24,%sp # make room for src/dst
link.w %a6,&-LOCAL_SIZE # init stack frame
fsave FP_SRC(%a6) # grab the "busy" frame
movm.l &0x0303,EXC_DREGS(%a6) # save d0-d1/a0-a1
fmovm.l %fpcr,%fpsr,%fpiar,USER_FPCR(%a6) # save ctrl regs
fmovm.x &0xc0,EXC_FPREGS(%a6) # save fp0-fp1 on stack
# the FPIAR holds the "current PC" of the faulting instruction
mov.l USER_FPIAR(%a6),EXC_EXTWPTR(%a6)
mov.l EXC_EXTWPTR(%a6),%a0 # fetch instruction addr
addq.l &0x4,EXC_EXTWPTR(%a6) # incr instruction ptr
bsr.l _imem_read_long # fetch the instruction words
mov.l %d0,EXC_OPWORD(%a6)
btst &0x5,EXC_CMDREG(%a6) # is instr an fmove out?
bne.w fovfl_out
lea FP_SRC(%a6),%a0 # pass: ptr to src op
bsr.l fix_skewed_ops # fix src op
# since, I believe, only NORMs and DENORMs can come through here,
# maybe we can avoid the subroutine call.
lea FP_SRC(%a6),%a0 # pass: ptr to src op
bsr.l set_tag_x # tag the operand type
mov.b %d0,STAG(%a6) # maybe NORM,DENORM
# bit five of the fp extension word separates the monadic and dyadic operations
# that can pass through fpsp_ovfl(). remember that fcmp, ftst, and fsincos
# will never take this exception.
btst &0x5,1+EXC_CMDREG(%a6) # is operation monadic or dyadic?
beq.b fovfl_extract # monadic
lea FP_DST(%a6),%a0 # pass: ptr to dst op
bsr.l set_tag_x # tag the operand type
cmpi.b %d0,&UNNORM # is operand an UNNORM?
bne.b fovfl_op2_done # no
bsr.l unnorm_fix # yes; convert to NORM,DENORM,or ZERO
fovfl_op2_done:
mov.b %d0,DTAG(%a6) # save dst optype tag
andi.l &0x00ff01ff,USER_FPSR(%a6) # zero all but accured field
fmov.l &0x0,%fpcr # zero current control regs
fmov.l &0x0,%fpsr
lea FP_SRC(%a6),%a0
lea FP_DST(%a6),%a1
# maybe we can make these entry points ONLY the OVFL entry points of each routine.
mov.l (tbl_unsupp.l,%pc,%d1.w*4),%d1 # fetch routine addr
jsr (tbl_unsupp.l,%pc,%d1.l*1)
# the operation has been emulated. the result is in fp0.
# the EXOP, if an exception occurred, is in fp1.
# we must save the default result regardless of whether
# traps are enabled or disabled.
bfextu EXC_CMDREG(%a6){&6:&3},%d0
bsr.l store_fpreg
# the exceptional possibilities we have left ourselves with are ONLY overflow
# and inexact. and, the inexact is such that overflow occurred and was disabled
# but inexact was enabled.
btst &ovfl_bit,FPCR_ENABLE(%a6)
bne.b fovfl_ovfl_on
# overflow is enabled AND overflow, of course, occurred. so, we have the EXOP
# in fp1. now, simply jump to _real_ovfl()!
fovfl_ovfl_on:
fmovm.x &0x40,FP_SRC(%a6) # save EXOP (fp1) to stack
btst &0x7,(%sp) # is trace on?
beq.l _fpsp_done # no
fmov.l %fpiar,0x8(%sp) # "Current PC" is in FPIAR
mov.w &0x2024,0x6(%sp) # stk fmt = 0x2; voff = 0x024
bra.l _real_trace
#########################################################################
# XDEF **************************************************************** #
# _fpsp_unfl(): 060FPSP entry point for FP Underflow exception. #
# #
# This handler should be the first code executed upon taking the #
# FP Underflow exception in an operating system. #
# #
# XREF **************************************************************** #
# _imem_read_long() - read instruction longword #
# fix_skewed_ops() - adjust src operand in fsave frame #
# set_tag_x() - determine optype of src/dst operands #
# store_fpreg() - store opclass 0 or 2 result to FP regfile #
# unnorm_fix() - change UNNORM operands to NORM or ZERO #
# load_fpn2() - load dst operand from FP regfile #
# fout() - emulate an opclass 3 instruction #
# tbl_unsupp - add of table of emulation routines for opclass 0,2 #
# _fpsp_done() - "callout" for 060FPSP exit (all work done!) #
# _real_ovfl() - "callout" for Overflow exception enabled code #
# _real_inex() - "callout" for Inexact exception enabled code #
# _real_trace() - "callout" for Trace exception code #
# #
# INPUT *************************************************************** #
# - The system stack contains the FP Unfl exception stack frame #
# - The fsave frame contains the source operand #
# #
# OUTPUT ************************************************************** #
# Underflow Exception enabled: #
# - The system stack is unchanged #
# - The fsave frame contains the adjusted src op for opclass 0,2 #
# Underflow Exception disabled: #
# - The system stack is unchanged #
# - The "exception present" flag in the fsave frame is cleared #
# #
# ALGORITHM *********************************************************** #
# On the 060, if an FP underflow is present as the result of any #
# instruction, the 060 will take an underflow exception whether the #
# exception is enabled or disabled in the FPCR. For the disabled case, #
# This handler emulates the instruction to determine what the correct #
# default result should be for the operation. This default result is #
# then stored in either the FP regfile, data regfile, or memory. #
# Finally, the handler exits through the "callout" _fpsp_done() #
# denoting that no exceptional conditions exist within the machine. #
# If the exception is enabled, then this handler must create the #
# exceptional operand and plave it in the fsave state frame, and store #
# the default result (only if the instruction is opclass 3). For #
# exceptions enabled, this handler must exit through the "callout" #
# _real_unfl() so that the operating system enabled overflow handler #
# can handle this case. #
# Two other conditions exist. First, if underflow was disabled #
# but the inexact exception was enabled and the result was inexact, #
# this handler must exit through the "callout" _real_inex(). #
# was inexact. #
# Also, in the case of an opclass three instruction where #
# underflow was disabled and the trace exception was enabled, this #
# handler must exit through the "callout" _real_trace(). #
# #
#########################################################################
global _fpsp_unfl
_fpsp_unfl:
#$# sub.l &24,%sp # make room for src/dst
link.w %a6,&-LOCAL_SIZE # init stack frame
fsave FP_SRC(%a6) # grab the "busy" frame
movm.l &0x0303,EXC_DREGS(%a6) # save d0-d1/a0-a1
fmovm.l %fpcr,%fpsr,%fpiar,USER_FPCR(%a6) # save ctrl regs
fmovm.x &0xc0,EXC_FPREGS(%a6) # save fp0-fp1 on stack
# the FPIAR holds the "current PC" of the faulting instruction
mov.l USER_FPIAR(%a6),EXC_EXTWPTR(%a6)
mov.l EXC_EXTWPTR(%a6),%a0 # fetch instruction addr
addq.l &0x4,EXC_EXTWPTR(%a6) # incr instruction ptr
bsr.l _imem_read_long # fetch the instruction words
mov.l %d0,EXC_OPWORD(%a6)
btst &0x5,EXC_CMDREG(%a6) # is instr an fmove out?
bne.w funfl_out
lea FP_SRC(%a6),%a0 # pass: ptr to src op
bsr.l fix_skewed_ops # fix src op
lea FP_SRC(%a6),%a0 # pass: ptr to src op
bsr.l set_tag_x # tag the operand type
mov.b %d0,STAG(%a6) # maybe NORM,DENORM
# bit five of the fp ext word separates the monadic and dyadic operations
# that can pass through fpsp_unfl(). remember that fcmp, and ftst
# will never take this exception.
btst &0x5,1+EXC_CMDREG(%a6) # is op monadic or dyadic?
beq.b funfl_extract # monadic
# now, what's left that's not dyadic is fsincos. we can distinguish it
# from all dyadics by the '0110xxx pattern
btst &0x4,1+EXC_CMDREG(%a6) # is op an fsincos?
bne.b funfl_extract # yes
lea FP_DST(%a6),%a0 # pass: ptr to dst op
bsr.l set_tag_x # tag the operand type
cmpi.b %d0,&UNNORM # is operand an UNNORM?
bne.b funfl_op2_done # no
bsr.l unnorm_fix # yes; convert to NORM,DENORM,or ZERO
funfl_op2_done:
mov.b %d0,DTAG(%a6) # save dst optype tag
fmov.l &0x0,%fpcr # zero current control regs
fmov.l &0x0,%fpsr
lea FP_SRC(%a6),%a0
lea FP_DST(%a6),%a1
# maybe we can make these entry points ONLY the OVFL entry points of each routine.
mov.l (tbl_unsupp.l,%pc,%d1.w*4),%d1 # fetch routine addr
jsr (tbl_unsupp.l,%pc,%d1.l*1)
# The `060 FPU multiplier hardware is such that if the result of a
# multiply operation is the smallest possible normalized number
# (0x00000000_80000000_00000000), then the machine will take an
# underflow exception. Since this is incorrect, we need to check
# if our emulation, after re-doing the operation, decided that
# no underflow was called for. We do these checks only in
# funfl_{unfl,inex}_on() because w/ both exceptions disabled, this
# special case will simply exit gracefully with the correct result.
# the exceptional possibilities we have left ourselves with are ONLY overflow
# and inexact. and, the inexact is such that overflow occurred and was disabled
# but inexact was enabled.
btst &unfl_bit,FPCR_ENABLE(%a6)
bne.b funfl_unfl_on
# overflow is enabled AND overflow, of course, occurred. so, we have the EXOP
# in fp1 (don't forget to save fp0). what to do now?
# well, we simply have to get to go to _real_unfl()!
funfl_unfl_on:
# The `060 FPU multiplier hardware is such that if the result of a
# multiply operation is the smallest possible normalized number
# (0x00000000_80000000_00000000), then the machine will take an
# underflow exception. Since this is incorrect, we check here to see
# if our emulation, after re-doing the operation, decided that
# no underflow was called for.
btst &unfl_bit,FPSR_EXCEPT(%a6)
beq.w funfl_chkinex
funfl_unfl_on2:
fmovm.x &0x40,FP_SRC(%a6) # save EXOP (fp1) to stack
frestore FP_SRC(%a6) # do this after fmovm,other f<op>s!
unlk %a6
bra.l _real_unfl
# undeflow occurred but is disabled. meanwhile, inexact is enabled. therefore,
# we must jump to real_inex().
funfl_inex_on:
# The `060 FPU multiplier hardware is such that if the result of a
# multiply operation is the smallest possible normalized number
# (0x00000000_80000000_00000000), then the machine will take an
# underflow exception.
# But, whether bogus or not, if inexact is enabled AND it occurred,
# then we have to branch to real_inex.
btst &inex2_bit,FPSR_EXCEPT(%a6)
beq.w funfl_exit
funfl_inex_on2:
fmovm.x &0x40,FP_SRC(%a6) # save EXOP to stack
mov.b &0xc4,1+EXC_VOFF(%a6) # vector offset = 0xc4
mov.w &0xe001,2+FP_SRC(%a6) # save exc status
btst &0x7,(%sp) # is trace on?
beq.l _fpsp_done # no
fmov.l %fpiar,0x8(%sp) # "Current PC" is in FPIAR
mov.w &0x2024,0x6(%sp) # stk fmt = 0x2; voff = 0x024
bra.l _real_trace
#########################################################################
# XDEF **************************************************************** #
# _fpsp_unsupp(): 060FPSP entry point for FP "Unimplemented #
# Data Type" exception. #
# #
# This handler should be the first code executed upon taking the #
# FP Unimplemented Data Type exception in an operating system. #
# #
# XREF **************************************************************** #
# _imem_read_{word,long}() - read instruction word/longword #
# fix_skewed_ops() - adjust src operand in fsave frame #
# set_tag_x() - determine optype of src/dst operands #
# store_fpreg() - store opclass 0 or 2 result to FP regfile #
# unnorm_fix() - change UNNORM operands to NORM or ZERO #
# load_fpn2() - load dst operand from FP regfile #
# load_fpn1() - load src operand from FP regfile #
# fout() - emulate an opclass 3 instruction #
# tbl_unsupp - add of table of emulation routines for opclass 0,2 #
# _real_inex() - "callout" to operating system inexact handler #
# _fpsp_done() - "callout" for exit; work all done #
# _real_trace() - "callout" for Trace enabled exception #
# funimp_skew() - adjust fsave src ops to "incorrect" value #
# _real_snan() - "callout" for SNAN exception #
# _real_operr() - "callout" for OPERR exception #
# _real_ovfl() - "callout" for OVFL exception #
# _real_unfl() - "callout" for UNFL exception #
# get_packed() - fetch packed operand from memory #
# #
# INPUT *************************************************************** #
# - The system stack contains the "Unimp Data Type" stk frame #
# - The fsave frame contains the ssrc op (for UNNORM/DENORM) #
# #
# OUTPUT ************************************************************** #
# If Inexact exception (opclass 3): #
# - The system stack is changed to an Inexact exception stk frame #
# If SNAN exception (opclass 3): #
# - The system stack is changed to an SNAN exception stk frame #
# If OPERR exception (opclass 3): #
# - The system stack is changed to an OPERR exception stk frame #
# If OVFL exception (opclass 3): #
# - The system stack is changed to an OVFL exception stk frame #
# If UNFL exception (opclass 3): #
# - The system stack is changed to an UNFL exception stack frame #
# If Trace exception enabled: #
# - The system stack is changed to a Trace exception stack frame #
# Else: (normal case) #
# - Correct result has been stored as appropriate #
# #
# ALGORITHM *********************************************************** #
# Two main instruction types can enter here: (1) DENORM or UNNORM #
# unimplemented data types. These can be either opclass 0,2 or 3 #
# instructions, and (2) PACKED unimplemented data format instructions #
# also of opclasses 0,2, or 3. #
# For UNNORM/DENORM opclass 0 and 2, the handler fetches the src #
# operand from the fsave state frame and the dst operand (if dyadic) #
# from the FP register file. The instruction is then emulated by #
# choosing an emulation routine from a table of routines indexed by #
# instruction type. Once the instruction has been emulated and result #
# saved, then we check to see if any enabled exceptions resulted from #
# instruction emulation. If none, then we exit through the "callout" #
# _fpsp_done(). If there is an enabled FP exception, then we insert #
# this exception into the FPU in the fsave state frame and then exit #
# through _fpsp_done(). #
# PACKED opclass 0 and 2 is similar in how the instruction is #
# emulated and exceptions handled. The differences occur in how the #
# handler loads the packed op (by calling get_packed() routine) and #
# by the fact that a Trace exception could be pending for PACKED ops. #
# If a Trace exception is pending, then the current exception stack #
# frame is changed to a Trace exception stack frame and an exit is #
# made through _real_trace(). #
# For UNNORM/DENORM opclass 3, the actual move out to memory is #
# performed by calling the routine fout(). If no exception should occur #
# as the result of emulation, then an exit either occurs through #
# _fpsp_done() or through _real_trace() if a Trace exception is pending #
# (a Trace stack frame must be created here, too). If an FP exception #
# should occur, then we must create an exception stack frame of that #
# type and jump to either _real_snan(), _real_operr(), _real_inex(), #
# _real_unfl(), or _real_ovfl() as appropriate. PACKED opclass 3 #
# emulation is performed in a similar manner. #
# #
#########################################################################
#
# (1) DENORM and UNNORM (unimplemented) data types:
#
# post-instruction
# *****************
# * EA *
# pre-instruction * *
# ***************** *****************
# * 0x0 * 0x0dc * * 0x3 * 0x0dc *
# ***************** *****************
# * Next * * Next *
# * PC * * PC *
# ***************** *****************
# * SR * * SR *
# ***************** *****************
#
# (2) PACKED format (unsupported) opclasses two and three:
# *****************
# * EA *
# * *
# *****************
# * 0x2 * 0x0dc *
# *****************
# * Next *
# * PC *
# *****************
# * SR *
# *****************
#
global _fpsp_unsupp
_fpsp_unsupp:
link.w %a6,&-LOCAL_SIZE # init stack frame
fsave FP_SRC(%a6) # save fp state
movm.l &0x0303,EXC_DREGS(%a6) # save d0-d1/a0-a1
fmovm.l %fpcr,%fpsr,%fpiar,USER_FPCR(%a6) # save ctrl regs
fmovm.x &0xc0,EXC_FPREGS(%a6) # save fp0-fp1 on stack
btst &0x5,EXC_SR(%a6) # user or supervisor mode?
bne.b fu_s
fu_u:
mov.l %usp,%a0 # fetch user stack pointer
mov.l %a0,EXC_A7(%a6) # save on stack
bra.b fu_cont
# if the exception is an opclass zero or two unimplemented data type
# exception, then the a7' calculated here is wrong since it doesn't
# stack an ea. however, we don't need an a7' for this case anyways.
fu_s:
lea 0x4+EXC_EA(%a6),%a0 # load old a7'
mov.l %a0,EXC_A7(%a6) # save on stack
fu_cont:
# the FPIAR holds the "current PC" of the faulting instruction
# the FPIAR should be set correctly for ALL exceptions passing through
# this point.
mov.l USER_FPIAR(%a6),EXC_EXTWPTR(%a6)
mov.l EXC_EXTWPTR(%a6),%a0 # fetch instruction addr
addq.l &0x4,EXC_EXTWPTR(%a6) # incr instruction ptr
bsr.l _imem_read_long # fetch the instruction words
mov.l %d0,EXC_OPWORD(%a6) # store OPWORD and EXTWORD
############################
clr.b SPCOND_FLG(%a6) # clear special condition flag
# Separate opclass three (fpn-to-mem) ops since they have a different
# stack frame and protocol.
btst &0x5,EXC_CMDREG(%a6) # is it an fmove out?
bne.w fu_out # yes
# Separate packed opclass two instructions.
bfextu EXC_CMDREG(%a6){&0:&6},%d0
cmpi.b %d0,&0x13
beq.w fu_in_pack
# I'm not sure at this point what FPSR bits are valid for this instruction.
# so, since the emulation routines re-create them anyways, zero exception field
andi.l &0x00ff00ff,USER_FPSR(%a6) # zero exception field
fmov.l &0x0,%fpcr # zero current control regs
fmov.l &0x0,%fpsr
# Opclass two w/ memory-to-fpn operation will have an incorrect extended
# precision format if the src format was single or double and the
# source data type was an INF, NAN, DENORM, or UNNORM
lea FP_SRC(%a6),%a0 # pass ptr to input
bsr.l fix_skewed_ops
# we don't know whether the src operand or the dst operand (or both) is the
# UNNORM or DENORM. call the function that tags the operand type. if the
# input is an UNNORM, then convert it to a NORM, DENORM, or ZERO.
lea FP_SRC(%a6),%a0 # pass: ptr to src op
bsr.l set_tag_x # tag the operand type
cmpi.b %d0,&UNNORM # is operand an UNNORM?
bne.b fu_op2 # no
bsr.l unnorm_fix # yes; convert to NORM,DENORM,or ZERO
# bit five of the fp extension word separates the monadic and dyadic operations
# at this point
btst &0x5,1+EXC_CMDREG(%a6) # is operation monadic or dyadic?
beq.b fu_extract # monadic
cmpi.b 1+EXC_CMDREG(%a6),&0x3a # is operation an ftst?
beq.b fu_extract # yes, so it's monadic, too
bsr.l load_fpn2 # load dst into FP_DST
lea FP_DST(%a6),%a0 # pass: ptr to dst op
bsr.l set_tag_x # tag the operand type
cmpi.b %d0,&UNNORM # is operand an UNNORM?
bne.b fu_op2_done # no
bsr.l unnorm_fix # yes; convert to NORM,DENORM,or ZERO
fu_op2_done:
mov.b %d0,DTAG(%a6) # save dst optype tag
#
# Exceptions in order of precedence:
# BSUN : none
# SNAN : all dyadic ops
# OPERR : fsqrt(-NORM)
# OVFL : all except ftst,fcmp
# UNFL : all except ftst,fcmp
# DZ : fdiv
# INEX2 : all except ftst,fcmp
# INEX1 : none (packed doesn't go through here)
#
# we determine the highest priority exception(if any) set by the
# emulation routine that has also been enabled by the user.
mov.b FPCR_ENABLE(%a6),%d0 # fetch exceptions set
bne.b fu_in_ena # some are enabled
fu_in_cont:
# fcmp and ftst do not store any result.
mov.b 1+EXC_CMDREG(%a6),%d0 # fetch extension
andi.b &0x38,%d0 # extract bits 3-5
cmpi.b %d0,&0x38 # is instr fcmp or ftst?
beq.b fu_in_exit # yes
bfextu EXC_CMDREG(%a6){&6:&3},%d0 # dyadic; load dst reg
bsr.l store_fpreg # store the result
fu_in_ena:
and.b FPSR_EXCEPT(%a6),%d0 # keep only ones enabled
bfffo %d0{&24:&8},%d0 # find highest priority exception
bne.b fu_in_exc # there is at least one set
#
# No exceptions occurred that were also enabled. Now:
#
# if (OVFL && ovfl_disabled && inexact_enabled) {
# branch to _real_inex() (even if the result was exact!);
# } else {
# save the result in the proper fp reg (unless the op is fcmp or ftst);
# return;
# }
#
btst &ovfl_bit,FPSR_EXCEPT(%a6) # was overflow set?
beq.b fu_in_cont # no
fu_in_ovflchk:
btst &inex2_bit,FPCR_ENABLE(%a6) # was inexact enabled?
beq.b fu_in_cont # no
bra.w fu_in_exc_ovfl # go insert overflow frame
#
# An exception occurred and that exception was enabled:
#
# shift enabled exception field into lo byte of d0;
# if (((INEX2 || INEX1) && inex_enabled && OVFL && ovfl_disabled) ||
# ((INEX2 || INEX1) && inex_enabled && UNFL && unfl_disabled)) {
# /*
# * this is the case where we must call _real_inex() now or else
# * there will be no other way to pass it the exceptional operand
# */
# call _real_inex();
# } else {
# restore exc state (SNAN||OPERR||OVFL||UNFL||DZ||INEX) into the FPU;
# }
#
fu_in_exc:
subi.l &24,%d0 # fix offset to be 0-8
cmpi.b %d0,&0x6 # is exception INEX? (6)
bne.b fu_in_exc_exit # no
# the enabled exception was inexact
btst &unfl_bit,FPSR_EXCEPT(%a6) # did disabled underflow occur?
bne.w fu_in_exc_unfl # yes
btst &ovfl_bit,FPSR_EXCEPT(%a6) # did disabled overflow occur?
bne.w fu_in_exc_ovfl # yes
# here, we insert the correct fsave status value into the fsave frame for the
# corresponding exception. the operand in the fsave frame should be the original
# src operand.
fu_in_exc_exit:
mov.l %d0,-(%sp) # save d0
bsr.l funimp_skew # skew sgl or dbl inputs
mov.l (%sp)+,%d0 # restore d0
mov.w (tbl_except.b,%pc,%d0.w*2),2+FP_SRC(%a6) # create exc status
# If the input operand to this operation was opclass two and a single
# or double precision denorm, inf, or nan, the operand needs to be
# "corrected" in order to have the proper equivalent extended precision
# number.
global fix_skewed_ops
fix_skewed_ops:
bfextu EXC_CMDREG(%a6){&0:&6},%d0 # extract opclass,src fmt
cmpi.b %d0,&0x11 # is class = 2 & fmt = sgl?
beq.b fso_sgl # yes
cmpi.b %d0,&0x15 # is class = 2 & fmt = dbl?
beq.b fso_dbl # yes
rts # no
fso_sgl_dnrm_zero:
andi.l &0x7fffffff,LOCAL_HI(%a0) # clear j-bit
beq.b fso_zero # it's a skewed zero
fso_sgl_dnrm:
# here, we count on norm not to alter a0...
bsr.l norm # normalize mantissa
neg.w %d0 # -shft amt
addi.w &0x3f81,%d0 # adjust new exponent
andi.w &0x8000,LOCAL_EX(%a0) # clear old exponent
or.w %d0,LOCAL_EX(%a0) # insert new exponent
rts
fso_dbl_dnrm_zero:
andi.l &0x7fffffff,LOCAL_HI(%a0) # clear j-bit
bne.b fso_dbl_dnrm # it's a skewed denorm
tst.l LOCAL_LO(%a0) # is it a zero?
beq.b fso_zero # yes
fso_dbl_dnrm:
# here, we count on norm not to alter a0...
bsr.l norm # normalize mantissa
neg.w %d0 # -shft amt
addi.w &0x3c01,%d0 # adjust new exponent
andi.w &0x8000,LOCAL_EX(%a0) # clear old exponent
or.w %d0,LOCAL_EX(%a0) # insert new exponent
rts
# fmove out took an unimplemented data type exception.
# the src operand is in FP_SRC. Call _fout() to write out the result and
# to determine which exceptions, if any, to take.
fu_out:
# Separate packed move outs from the UNNORM and DENORM move outs.
bfextu EXC_CMDREG(%a6){&3:&3},%d0
cmpi.b %d0,&0x3
beq.w fu_out_pack
cmpi.b %d0,&0x7
beq.w fu_out_pack
# I'm not sure at this point what FPSR bits are valid for this instruction.
# so, since the emulation routines re-create them anyways, zero exception field.
# fmove out doesn't affect ccodes.
and.l &0xffff00ff,USER_FPSR(%a6) # zero exception field
fmov.l &0x0,%fpcr # zero current control regs
fmov.l &0x0,%fpsr
# the src can ONLY be a DENORM or an UNNORM! so, don't make any big subroutine
# call here. just figure out what it is...
mov.w FP_SRC_EX(%a6),%d0 # get exponent
andi.w &0x7fff,%d0 # strip sign
beq.b fu_out_denorm # it's a DENORM
lea FP_SRC(%a6),%a0
bsr.l unnorm_fix # yes; fix it
mov.l (%a6),EXC_A6(%a6) # in case a6 changes
bsr.l fout # call fmove out routine
# Exceptions in order of precedence:
# BSUN : none
# SNAN : none
# OPERR : fmove.{b,w,l} out of large UNNORM
# OVFL : fmove.{s,d}
# UNFL : fmove.{s,d,x}
# DZ : none
# INEX2 : all
# INEX1 : none (packed doesn't travel through here)
# determine the highest priority exception(if any) set by the
# emulation routine that has also been enabled by the user.
mov.b FPCR_ENABLE(%a6),%d0 # fetch exceptions enabled
bne.w fu_out_ena # some are enabled
fu_out_done:
mov.l EXC_A6(%a6),(%a6) # in case a6 changed
# on extended precision opclass three instructions using pre-decrement or
# post-increment addressing mode, the address register is not updated. is the
# address register was the stack pointer used from user mode, then let's update
# it here. if it was used from supervisor mode, then we have to handle this
# as a special case.
btst &0x5,EXC_SR(%a6)
bne.b fu_out_done_s
btst &0x7,(%sp) # is trace on?
bne.b fu_out_trace # yes
bra.l _fpsp_done
# is the ea mode pre-decrement of the stack pointer from supervisor mode?
# ("fmov.x fpm,-(a7)") if so,
fu_out_done_s:
cmpi.b SPCOND_FLG(%a6),&mda7_flg
bne.b fu_out_done_cont
# the extended precision result is still in fp0. but, we need to save it
# somewhere on the stack until we can copy it to its final resting place.
# here, we're counting on the top of the stack to be the old place-holders
# for fp0/fp1 which have already been restored. that way, we can write
# over those destinations with the shifted stack frame.
fmovm.x &0x80,FP_SRC(%a6) # put answer on stack
# now, copy the result to the proper place on the stack
mov.l LOCAL_SIZE+FP_SRC_EX(%sp),LOCAL_SIZE+EXC_SR+0x0(%sp)
mov.l LOCAL_SIZE+FP_SRC_HI(%sp),LOCAL_SIZE+EXC_SR+0x4(%sp)
mov.l LOCAL_SIZE+FP_SRC_LO(%sp),LOCAL_SIZE+EXC_SR+0x8(%sp)
add.l &LOCAL_SIZE-0x8,%sp
btst &0x7,(%sp)
bne.b fu_out_trace
bra.l _fpsp_done
fu_out_ena:
and.b FPSR_EXCEPT(%a6),%d0 # keep only ones enabled
bfffo %d0{&24:&8},%d0 # find highest priority exception
bne.b fu_out_exc # there is at least one set
# no exceptions were set.
# if a disabled overflow occurred and inexact was enabled but the result
# was exact, then a branch to _real_inex() is made.
btst &ovfl_bit,FPSR_EXCEPT(%a6) # was overflow set?
beq.w fu_out_done # no
fu_out_ovflchk:
btst &inex2_bit,FPCR_ENABLE(%a6) # was inexact enabled?
beq.w fu_out_done # no
bra.w fu_inex # yes
#
# The fp move out that took the "Unimplemented Data Type" exception was
# being traced. Since the stack frames are similar, get the "current" PC
# from FPIAR and put it in the trace stack frame then jump to _real_trace().
#
# UNSUPP FRAME TRACE FRAME
# ***************** *****************
# * EA * * Current *
# * * * PC *
# ***************** *****************
# * 0x3 * 0x0dc * * 0x2 * 0x024 *
# ***************** *****************
# * Next * * Next *
# * PC * * PC *
# ***************** *****************
# * SR * * SR *
# ***************** *****************
#
fu_out_trace:
mov.w &0x2024,0x6(%sp)
fmov.l %fpiar,0x8(%sp)
bra.l _real_trace
# an exception occurred and that exception was enabled.
fu_out_exc:
subi.l &24,%d0 # fix offset to be 0-8
# we don't mess with the existing fsave frame. just re-insert it and
# jump to the "_real_{}()" handler...
mov.w (tbl_fu_out.b,%pc,%d0.w*2),%d0
jmp (tbl_fu_out.b,%pc,%d0.w*1)
swbeg &0x8
tbl_fu_out:
short tbl_fu_out - tbl_fu_out # BSUN can't happen
short tbl_fu_out - tbl_fu_out # SNAN can't happen
short fu_operr - tbl_fu_out # OPERR
short fu_ovfl - tbl_fu_out # OVFL
short fu_unfl - tbl_fu_out # UNFL
short tbl_fu_out - tbl_fu_out # DZ can't happen
short fu_inex - tbl_fu_out # INEX2
short tbl_fu_out - tbl_fu_out # INEX1 won't make it here
# for snan,operr,ovfl,unfl, src op is still in FP_SRC so just
# frestore it.
fu_snan:
fmovm.x EXC_FPREGS(%a6),&0xc0 # restore fp0/fp1
fmovm.l USER_FPCR(%a6),%fpcr,%fpsr,%fpiar # restore ctrl regs
movm.l EXC_DREGS(%a6),&0x0303 # restore d0-d1/a0-a1
# underflow can happen for extended precision. extended precision opclass
# three instruction exceptions don't update the stack pointer. so, if the
# exception occurred from user mode, then simply update a7 and exit normally.
# if the exception occurred from supervisor mode, check if
fu_unfl:
mov.l EXC_A6(%a6),(%a6) # restore a6
btst &0x5,EXC_SR(%a6)
bne.w fu_unfl_s
mov.l EXC_A7(%a6),%a0 # restore a7 whether we need
mov.l %a0,%usp # to or not...
fu_unfl_cont:
fmovm.x &0x40,FP_SRC(%a6) # save EXOP to the stack
fu_unfl_s:
cmpi.b SPCOND_FLG(%a6),&mda7_flg # was the <ea> mode -(sp)?
bne.b fu_unfl_cont
# the extended precision result is still in fp0. but, we need to save it
# somewhere on the stack until we can copy it to its final resting place
# (where the exc frame is currently). make sure it's not at the top of the
# frame or it will get overwritten when the exc stack frame is shifted "down".
fmovm.x &0x80,FP_SRC(%a6) # put answer on stack
fmovm.x &0x40,FP_DST(%a6) # put EXOP on stack
# now, copy the result to the proper place on the stack
mov.l LOCAL_SIZE+FP_SRC_EX(%sp),LOCAL_SIZE+EXC_SR+0x0(%sp)
mov.l LOCAL_SIZE+FP_SRC_HI(%sp),LOCAL_SIZE+EXC_SR+0x4(%sp)
mov.l LOCAL_SIZE+FP_SRC_LO(%sp),LOCAL_SIZE+EXC_SR+0x8(%sp)
add.l &LOCAL_SIZE-0x8,%sp
bra.l _real_unfl
# fmove in and out enter here.
fu_inex:
fmovm.x &0x40,FP_SRC(%a6) # save EXOP to the stack
# I'm not sure at this point what FPSR bits are valid for this instruction.
# so, since the emulation routines re-create them anyways, zero exception field
andi.l &0x0ff00ff,USER_FPSR(%a6) # zero exception field
fmov.l &0x0,%fpcr # zero current control regs
fmov.l &0x0,%fpsr
bsr.l get_packed # fetch packed src operand
lea FP_SRC(%a6),%a0 # pass ptr to src
bsr.l set_tag_x # set src optype tag
# bit five of the fp extension word separates the monadic and dyadic operations
# at this point
btst &0x5,1+EXC_CMDREG(%a6) # is operation monadic or dyadic?
beq.b fu_extract_p # monadic
cmpi.b 1+EXC_CMDREG(%a6),&0x3a # is operation an ftst?
beq.b fu_extract_p # yes, so it's monadic, too
bsr.l load_fpn2 # load dst into FP_DST
lea FP_DST(%a6),%a0 # pass: ptr to dst op
bsr.l set_tag_x # tag the operand type
cmpi.b %d0,&UNNORM # is operand an UNNORM?
bne.b fu_op2_done_p # no
bsr.l unnorm_fix # yes; convert to NORM,DENORM,or ZERO
fu_op2_done_p:
mov.b %d0,DTAG(%a6) # save dst optype tag
#
# Exceptions in order of precedence:
# BSUN : none
# SNAN : all dyadic ops
# OPERR : fsqrt(-NORM)
# OVFL : all except ftst,fcmp
# UNFL : all except ftst,fcmp
# DZ : fdiv
# INEX2 : all except ftst,fcmp
# INEX1 : all
#
# we determine the highest priority exception(if any) set by the
# emulation routine that has also been enabled by the user.
mov.b FPCR_ENABLE(%a6),%d0 # fetch exceptions enabled
bne.w fu_in_ena_p # some are enabled
fu_in_cont_p:
# fcmp and ftst do not store any result.
mov.b 1+EXC_CMDREG(%a6),%d0 # fetch extension
andi.b &0x38,%d0 # extract bits 3-5
cmpi.b %d0,&0x38 # is instr fcmp or ftst?
beq.b fu_in_exit_p # yes
bfextu EXC_CMDREG(%a6){&6:&3},%d0 # dyadic; load dst reg
bsr.l store_fpreg # store the result
fu_in_exit_p:
btst &0x5,EXC_SR(%a6) # user or supervisor?
bne.w fu_in_exit_s_p # supervisor
mov.l EXC_A7(%a6),%a0 # update user a7
mov.l %a0,%usp
btst &0x7,(%sp) # is trace on?
bne.w fu_trace_p # yes
bra.l _fpsp_done # exit to os
# the exception occurred in supervisor mode. check to see if the
# addressing mode was (a7)+. if so, we'll need to shift the
# stack frame "up".
fu_in_exit_s_p:
btst &mia7_bit,SPCOND_FLG(%a6) # was ea mode (a7)+
beq.b fu_in_exit_cont_p # no
# shift the stack frame "up". we don't really care about the <ea> field.
mov.l 0x4(%sp),0x10(%sp)
mov.l 0x0(%sp),0xc(%sp)
add.l &0xc,%sp
btst &0x7,(%sp) # is trace on?
bne.w fu_trace_p # yes
bra.l _fpsp_done # exit to os
fu_in_ena_p:
and.b FPSR_EXCEPT(%a6),%d0 # keep only ones enabled & set
bfffo %d0{&24:&8},%d0 # find highest priority exception
bne.b fu_in_exc_p # at least one was set
#
# No exceptions occurred that were also enabled. Now:
#
# if (OVFL && ovfl_disabled && inexact_enabled) {
# branch to _real_inex() (even if the result was exact!);
# } else {
# save the result in the proper fp reg (unless the op is fcmp or ftst);
# return;
# }
#
btst &ovfl_bit,FPSR_EXCEPT(%a6) # was overflow set?
beq.w fu_in_cont_p # no
fu_in_ovflchk_p:
btst &inex2_bit,FPCR_ENABLE(%a6) # was inexact enabled?
beq.w fu_in_cont_p # no
bra.w fu_in_exc_ovfl_p # do _real_inex() now
#
# An exception occurred and that exception was enabled:
#
# shift enabled exception field into lo byte of d0;
# if (((INEX2 || INEX1) && inex_enabled && OVFL && ovfl_disabled) ||
# ((INEX2 || INEX1) && inex_enabled && UNFL && unfl_disabled)) {
# /*
# * this is the case where we must call _real_inex() now or else
# * there will be no other way to pass it the exceptional operand
# */
# call _real_inex();
# } else {
# restore exc state (SNAN||OPERR||OVFL||UNFL||DZ||INEX) into the FPU;
# }
#
fu_in_exc_p:
subi.l &24,%d0 # fix offset to be 0-8
cmpi.b %d0,&0x6 # is exception INEX? (6 or 7)
blt.b fu_in_exc_exit_p # no
# the enabled exception was inexact
btst &unfl_bit,FPSR_EXCEPT(%a6) # did disabled underflow occur?
bne.w fu_in_exc_unfl_p # yes
btst &ovfl_bit,FPSR_EXCEPT(%a6) # did disabled overflow occur?
bne.w fu_in_exc_ovfl_p # yes
# here, we insert the correct fsave status value into the fsave frame for the
# corresponding exception. the operand in the fsave frame should be the original
# src operand.
# as a reminder for future predicted pain and agony, we are passing in fsave the
# "non-skewed" operand for cases of sgl and dbl src INFs,NANs, and DENORMs.
# this is INCORRECT for enabled SNAN which would give to the user the skewed SNAN!!!
fu_in_exc_exit_p:
btst &0x5,EXC_SR(%a6) # user or supervisor?
bne.w fu_in_exc_exit_s_p # supervisor
mov.l EXC_A7(%a6),%a0 # update user a7
mov.l %a0,%usp
# shift stack frame "up". who cares about <ea> field.
mov.l 0x4(%sp),0x10(%sp)
mov.l 0x0(%sp),0xc(%sp)
add.l &0xc,%sp
btst &0x7,(%sp) # is trace on?
bne.b fu_trace_p # yes
bra.l _fpsp_done # exit to os
#
# The opclass two PACKED instruction that took an "Unimplemented Data Type"
# exception was being traced. Make the "current" PC the FPIAR and put it in the
# trace stack frame then jump to _real_trace().
#
# UNSUPP FRAME TRACE FRAME
# ***************** *****************
# * EA * * Current *
# * * * PC *
# ***************** *****************
# * 0x2 * 0x0dc * * 0x2 * 0x024 *
# ***************** *****************
# * Next * * Next *
# * PC * * PC *
# ***************** *****************
# * SR * * SR *
# ***************** *****************
fu_trace_p:
mov.w &0x2024,0x6(%sp)
fmov.l %fpiar,0x8(%sp)
# I'm not sure at this point what FPSR bits are valid for this instruction.
# so, since the emulation routines re-create them anyways, zero exception field.
# fmove out doesn't affect ccodes.
and.l &0xffff00ff,USER_FPSR(%a6) # zero exception field
fmov.l &0x0,%fpcr # zero current control regs
fmov.l &0x0,%fpsr
bfextu EXC_CMDREG(%a6){&6:&3},%d0
bsr.l load_fpn1
# unlike other opclass 3, unimplemented data type exceptions, packed must be
# able to detect all operand types.
lea FP_SRC(%a6),%a0
bsr.l set_tag_x # tag the operand type
cmpi.b %d0,&UNNORM # is operand an UNNORM?
bne.b fu_op2_p # no
bsr.l unnorm_fix # yes; convert to NORM,DENORM,or ZERO
fu_op2_p:
mov.b %d0,STAG(%a6) # save src optype tag
mov.l (%a6),EXC_A6(%a6) # in case a6 changes
bsr.l fout # call fmove out routine
# Exceptions in order of precedence:
# BSUN : no
# SNAN : yes
# OPERR : if ((k_factor > +17) || (dec. exp exceeds 3 digits))
# OVFL : no
# UNFL : no
# DZ : no
# INEX2 : yes
# INEX1 : no
# determine the highest priority exception(if any) set by the
# emulation routine that has also been enabled by the user.
mov.b FPCR_ENABLE(%a6),%d0 # fetch exceptions enabled
bne.w fu_out_ena_p # some are enabled
btst &0x7,(%sp) # is trace on?
bne.w fu_trace_p # yes
bra.l _fpsp_done # exit to os
# the exception occurred in supervisor mode. check to see if the
# addressing mode was -(a7). if so, we'll need to shift the
# stack frame "down".
fu_out_exit_s_p:
btst &mda7_bit,SPCOND_FLG(%a6) # was ea mode -(a7)
beq.b fu_out_exit_cont_p # no
# now, copy the result to the proper place on the stack
mov.l LOCAL_SIZE+FP_DST_EX(%sp),LOCAL_SIZE+EXC_SR+0x0(%sp)
mov.l LOCAL_SIZE+FP_DST_HI(%sp),LOCAL_SIZE+EXC_SR+0x4(%sp)
mov.l LOCAL_SIZE+FP_DST_LO(%sp),LOCAL_SIZE+EXC_SR+0x8(%sp)
# an exception occurred and that exception was enabled.
# the only exception possible on packed move out are INEX, OPERR, and SNAN.
fu_out_exc_p:
cmpi.b %d0,&0x1a
bgt.w fu_inex_p2
beq.w fu_operr_p
# the instruction was "fmove.p fpn,-(a7)" from supervisor mode.
# the strategy is to move the exception frame "down" 12 bytes. then, we
# can store the default result where the exception frame was.
fmovm.x EXC_FPREGS(%a6),&0xc0 # restore fp0/fp1
fmovm.l USER_FPCR(%a6),%fpcr,%fpsr,%fpiar # restore ctrl regs
movm.l EXC_DREGS(%a6),&0x0303 # restore d0-d1/a0-a1
mov.w &0x30d8,EXC_VOFF(%a6) # vector offset = 0xd0
mov.w &0xe006,2+FP_SRC(%a6) # set fsave status
# now, we copy the default result to it's proper location
mov.l LOCAL_SIZE+FP_DST_EX(%sp),LOCAL_SIZE+0x4(%sp)
mov.l LOCAL_SIZE+FP_DST_HI(%sp),LOCAL_SIZE+0x8(%sp)
mov.l LOCAL_SIZE+FP_DST_LO(%sp),LOCAL_SIZE+0xc(%sp)
# the instruction was "fmove.p fpn,-(a7)" from supervisor mode.
# the strategy is to move the exception frame "down" 12 bytes. then, we
# can store the default result where the exception frame was.
fmovm.x EXC_FPREGS(%a6),&0xc0 # restore fp0/fp1
fmovm.l USER_FPCR(%a6),%fpcr,%fpsr,%fpiar # restore ctrl regs
movm.l EXC_DREGS(%a6),&0x0303 # restore d0-d1/a0-a1
mov.w &0x30d0,EXC_VOFF(%a6) # vector offset = 0xd0
mov.w &0xe004,2+FP_SRC(%a6) # set fsave status
# now, we copy the default result to it's proper location
mov.l LOCAL_SIZE+FP_DST_EX(%sp),LOCAL_SIZE+0x4(%sp)
mov.l LOCAL_SIZE+FP_DST_HI(%sp),LOCAL_SIZE+0x8(%sp)
mov.l LOCAL_SIZE+FP_DST_LO(%sp),LOCAL_SIZE+0xc(%sp)
# the instruction was "fmove.p fpn,-(a7)" from supervisor mode.
# the strategy is to move the exception frame "down" 12 bytes. then, we
# can store the default result where the exception frame was.
fmovm.x EXC_FPREGS(%a6),&0xc0 # restore fp0/fp1
fmovm.l USER_FPCR(%a6),%fpcr,%fpsr,%fpiar # restore ctrl regs
movm.l EXC_DREGS(%a6),&0x0303 # restore d0-d1/a0-a1
mov.w &0x30c4,EXC_VOFF(%a6) # vector offset = 0xc4
mov.w &0xe001,2+FP_SRC(%a6) # set fsave status
# now, we copy the default result to it's proper location
mov.l LOCAL_SIZE+FP_DST_EX(%sp),LOCAL_SIZE+0x4(%sp)
mov.l LOCAL_SIZE+FP_DST_HI(%sp),LOCAL_SIZE+0x8(%sp)
mov.l LOCAL_SIZE+FP_DST_LO(%sp),LOCAL_SIZE+0xc(%sp)
#
# if we're stuffing a source operand back into an fsave frame then we
# have to make sure that for single or double source operands that the
# format stuffed is as weird as the hardware usually makes it.
#
global funimp_skew
funimp_skew:
bfextu EXC_EXTWORD(%a6){&3:&3},%d0 # extract src specifier
cmpi.b %d0,&0x1 # was src sgl?
beq.b funimp_skew_sgl # yes
cmpi.b %d0,&0x5 # was src dbl?
beq.b funimp_skew_dbl # yes
rts
funimp_skew_sgl:
mov.w FP_SRC_EX(%a6),%d0 # fetch DENORM exponent
andi.w &0x7fff,%d0 # strip sign
beq.b funimp_skew_sgl_not
cmpi.w %d0,&0x3f80
bgt.b funimp_skew_sgl_not
neg.w %d0 # make exponent negative
addi.w &0x3f81,%d0 # find amt to shift
mov.l FP_SRC_HI(%a6),%d1 # fetch DENORM hi(man)
lsr.l %d0,%d1 # shift it
bset &31,%d1 # set j-bit
mov.l %d1,FP_SRC_HI(%a6) # insert new hi(man)
andi.w &0x8000,FP_SRC_EX(%a6) # clear old exponent
ori.w &0x3f80,FP_SRC_EX(%a6) # insert new "skewed" exponent
funimp_skew_sgl_not:
rts
#########################################################################
# XDEF **************************************************************** #
# _fpsp_effadd(): 060FPSP entry point for FP "Unimplemented #
# effective address" exception. #
# #
# This handler should be the first code executed upon taking the #
# FP Unimplemented Effective Address exception in an operating #
# system. #
# #
# XREF **************************************************************** #
# _imem_read_long() - read instruction longword #
# fix_skewed_ops() - adjust src operand in fsave frame #
# set_tag_x() - determine optype of src/dst operands #
# store_fpreg() - store opclass 0 or 2 result to FP regfile #
# unnorm_fix() - change UNNORM operands to NORM or ZERO #
# load_fpn2() - load dst operand from FP regfile #
# tbl_unsupp - add of table of emulation routines for opclass 0,2 #
# decbin() - convert packed data to FP binary data #
# _real_fpu_disabled() - "callout" for "FPU disabled" exception #
# _real_access() - "callout" for access error exception #
# _mem_read() - read extended immediate operand from memory #
# _fpsp_done() - "callout" for exit; work all done #
# _real_trace() - "callout" for Trace enabled exception #
# fmovm_dynamic() - emulate dynamic fmovm instruction #
# fmovm_ctrl() - emulate fmovm control instruction #
# #
# INPUT *************************************************************** #
# - The system stack contains the "Unimplemented <ea>" stk frame #
# #
# OUTPUT ************************************************************** #
# If access error: #
# - The system stack is changed to an access error stack frame #
# If FPU disabled: #
# - The system stack is changed to an FPU disabled stack frame #
# If Trace exception enabled: #
# - The system stack is changed to a Trace exception stack frame #
# Else: (normal case) #
# - None (correct result has been stored as appropriate) #
# #
# ALGORITHM *********************************************************** #
# This exception handles 3 types of operations: #
# (1) FP Instructions using extended precision or packed immediate #
# addressing mode. #
# (2) The "fmovm.x" instruction w/ dynamic register specification. #
# (3) The "fmovm.l" instruction w/ 2 or 3 control registers. #
# #
# For immediate data operations, the data is read in w/ a #
# _mem_read() "callout", converted to FP binary (if packed), and used #
# as the source operand to the instruction specified by the instruction #
# word. If no FP exception should be reported ads a result of the #
# emulation, then the result is stored to the destination register and #
# the handler exits through _fpsp_done(). If an enabled exc has been #
# signalled as a result of emulation, then an fsave state frame #
# corresponding to the FP exception type must be entered into the 060 #
# FPU before exiting. In either the enabled or disabled cases, we #
# must also check if a Trace exception is pending, in which case, we #
# must create a Trace exception stack frame from the current exception #
# stack frame. If no Trace is pending, we simply exit through #
# _fpsp_done(). #
# For "fmovm.x", call the routine fmovm_dynamic() which will #
# decode and emulate the instruction. No FP exceptions can be pending #
# as a result of this operation emulation. A Trace exception can be #
# pending, though, which means the current stack frame must be changed #
# to a Trace stack frame and an exit made through _real_trace(). #
# For the case of "fmovm.x Dn,-(a7)", where the offending instruction #
# was executed from supervisor mode, this handler must store the FP #
# register file values to the system stack by itself since #
# fmovm_dynamic() can't handle this. A normal exit is made through #
# fpsp_done(). #
# For "fmovm.l", fmovm_ctrl() is used to emulate the instruction. #
# Again, a Trace exception may be pending and an exit made through #
# _real_trace(). Else, a normal exit is made through _fpsp_done(). #
# #
# Before any of the above is attempted, it must be checked to #
# see if the FPU is disabled. Since the "Unimp <ea>" exception is taken #
# before the "FPU disabled" exception, but the "FPU disabled" exception #
# has higher priority, we check the disabled bit in the PCR. If set, #
# then we must create an 8 word "FPU disabled" exception stack frame #
# from the current 4 word exception stack frame. This includes #
# reproducing the effective address of the instruction to put on the #
# new stack frame. #
# #
# In the process of all emulation work, if a _mem_read() #
# "callout" returns a failing result indicating an access error, then #
# we must create an access error stack frame from the current stack #
# frame. This information includes a faulting address and a fault- #
# status-longword. These are created within this handler. #
# #
#########################################################################
global _fpsp_effadd
_fpsp_effadd:
# This exception type takes priority over the "Line F Emulator"
# exception. Therefore, the FPU could be disabled when entering here.
# So, we must check to see if it's disabled and handle that case separately.
mov.l %d0,-(%sp) # save d0
movc %pcr,%d0 # load proc cr
btst &0x1,%d0 # is FPU disabled?
bne.w iea_disabled # yes
mov.l (%sp)+,%d0 # restore d0
link %a6,&-LOCAL_SIZE # init stack frame
movm.l &0x0303,EXC_DREGS(%a6) # save d0-d1/a0-a1
fmovm.l %fpcr,%fpsr,%fpiar,USER_FPCR(%a6) # save ctrl regs
fmovm.x &0xc0,EXC_FPREGS(%a6) # save fp0-fp1 on stack
# PC of instruction that took the exception is the PC in the frame
mov.l EXC_PC(%a6),EXC_EXTWPTR(%a6)
mov.l EXC_EXTWPTR(%a6),%a0 # fetch instruction addr
addq.l &0x4,EXC_EXTWPTR(%a6) # incr instruction ptr
bsr.l _imem_read_long # fetch the instruction words
mov.l %d0,EXC_OPWORD(%a6) # store OPWORD and EXTWORD
tst.w %d0 # is operation fmovem?
bmi.w iea_fmovm # yes
#
# here, we will have:
# fabs fdabs fsabs facos fmod
# fadd fdadd fsadd fasin frem
# fcmp fatan fscale
# fdiv fddiv fsdiv fatanh fsin
# fint fcos fsincos
# fintrz fcosh fsinh
# fmove fdmove fsmove fetox ftan
# fmul fdmul fsmul fetoxm1 ftanh
# fneg fdneg fsneg fgetexp ftentox
# fsgldiv fgetman ftwotox
# fsglmul flog10
# fsqrt flog2
# fsub fdsub fssub flogn
# ftst flognp1
# which can all use f<op>.{x,p}
# so, now it's immediate data extended precision AND PACKED FORMAT!
#
iea_op:
andi.l &0x00ff00ff,USER_FPSR(%a6)
btst &0xa,%d0 # is src fmt x or p?
bne.b iea_op_pack # packed
mov.l EXC_EXTWPTR(%a6),%a0 # pass: ptr to #<data>
lea FP_SRC(%a6),%a1 # pass: ptr to super addr
mov.l &0xc,%d0 # pass: 12 bytes
bsr.l _imem_read # read extended immediate
tst.l %d1 # did ifetch fail?
bne.w iea_iacc # yes
bra.b iea_op_setsrc
iea_op_pack:
mov.l EXC_EXTWPTR(%a6),%a0 # pass: ptr to #<data>
lea FP_SRC(%a6),%a1 # pass: ptr to super dst
mov.l &0xc,%d0 # pass: 12 bytes
bsr.l _imem_read # read packed operand
tst.l %d1 # did ifetch fail?
bne.w iea_iacc # yes
# The packed operand is an INF or a NAN if the exponent field is all ones.
bfextu FP_SRC(%a6){&1:&15},%d0 # get exp
cmpi.w %d0,&0x7fff # INF or NAN?
beq.b iea_op_setsrc # operand is an INF or NAN
# The packed operand is a zero if the mantissa is all zero, else it's
# a normal packed op.
mov.b 3+FP_SRC(%a6),%d0 # get byte 4
andi.b &0x0f,%d0 # clear all but last nybble
bne.b iea_op_gp_not_spec # not a zero
tst.l FP_SRC_HI(%a6) # is lw 2 zero?
bne.b iea_op_gp_not_spec # not a zero
tst.l FP_SRC_LO(%a6) # is lw 3 zero?
beq.b iea_op_setsrc # operand is a ZERO
iea_op_gp_not_spec:
lea FP_SRC(%a6),%a0 # pass: ptr to packed op
bsr.l decbin # convert to extended
fmovm.x &0x80,FP_SRC(%a6) # make this the srcop
iea_op_setsrc:
addi.l &0xc,EXC_EXTWPTR(%a6) # update extension word pointer
# FP_SRC now holds the src operand.
lea FP_SRC(%a6),%a0 # pass: ptr to src op
bsr.l set_tag_x # tag the operand type
mov.b %d0,STAG(%a6) # could be ANYTHING!!!
cmpi.b %d0,&UNNORM # is operand an UNNORM?
bne.b iea_op_getdst # no
bsr.l unnorm_fix # yes; convert to NORM/DENORM/ZERO
mov.b %d0,STAG(%a6) # set new optype tag
iea_op_getdst:
clr.b STORE_FLG(%a6) # clear "store result" boolean
btst &0x5,1+EXC_CMDREG(%a6) # is operation monadic or dyadic?
beq.b iea_op_extract # monadic
btst &0x4,1+EXC_CMDREG(%a6) # is operation fsincos,ftst,fcmp?
bne.b iea_op_spec # yes
lea FP_DST(%a6),%a0 # pass: ptr to dst op
bsr.l set_tag_x # tag the operand type
mov.b %d0,DTAG(%a6) # could be ANYTHING!!!
cmpi.b %d0,&UNNORM # is operand an UNNORM?
bne.b iea_op_extract # no
bsr.l unnorm_fix # yes; convert to NORM/DENORM/ZERO
mov.b %d0,DTAG(%a6) # set new optype tag
bra.b iea_op_extract
# the operation is fsincos, ftst, or fcmp. only fcmp is dyadic
iea_op_spec:
btst &0x3,1+EXC_CMDREG(%a6) # is operation fsincos?
beq.b iea_op_extract # yes
# now, we're left with ftst and fcmp. so, first let's tag them so that they don't
# store a result. then, only fcmp will branch back and pick up a dst operand.
st STORE_FLG(%a6) # don't store a final result
btst &0x1,1+EXC_CMDREG(%a6) # is operation fcmp?
beq.b iea_op_loaddst # yes
#
# Exceptions in order of precedence:
# BSUN : none
# SNAN : all operations
# OPERR : all reg-reg or mem-reg operations that can normally operr
# OVFL : same as OPERR
# UNFL : same as OPERR
# DZ : same as OPERR
# INEX2 : same as OPERR
# INEX1 : all packed immediate operations
#
# we determine the highest priority exception(if any) set by the
# emulation routine that has also been enabled by the user.
mov.b FPCR_ENABLE(%a6),%d0 # fetch exceptions enabled
bne.b iea_op_ena # some are enabled
# now, we save the result, unless, of course, the operation was ftst or fcmp.
# these don't save results.
iea_op_save:
tst.b STORE_FLG(%a6) # does this op store a result?
bne.b iea_op_exit1 # exit with no frestore
iea_op_store:
bfextu EXC_CMDREG(%a6){&6:&3},%d0 # fetch dst regno
bsr.l store_fpreg # store the result
iea_op_exit1:
mov.l EXC_PC(%a6),USER_FPIAR(%a6) # set FPIAR to "Current PC"
mov.l EXC_EXTWPTR(%a6),EXC_PC(%a6) # set "Next PC" in exc frame
btst &0x7,(%sp) # is trace on?
bne.w iea_op_trace # yes
bra.l _fpsp_done # exit to os
iea_op_ena:
and.b FPSR_EXCEPT(%a6),%d0 # keep only ones enable and set
bfffo %d0{&24:&8},%d0 # find highest priority exception
bne.b iea_op_exc # at least one was set
# no exception occurred. now, did a disabled, exact overflow occur with inexact
# enabled? if so, then we have to stuff an overflow frame into the FPU.
btst &ovfl_bit,FPSR_EXCEPT(%a6) # did overflow occur?
beq.b iea_op_save
iea_op_ovfl:
btst &inex2_bit,FPCR_ENABLE(%a6) # is inexact enabled?
beq.b iea_op_store # no
bra.b iea_op_exc_ovfl # yes
# an enabled exception occurred. we have to insert the exception type back into
# the machine.
iea_op_exc:
subi.l &24,%d0 # fix offset to be 0-8
cmpi.b %d0,&0x6 # is exception INEX?
bne.b iea_op_exc_force # no
# the enabled exception was inexact. so, if it occurs with an overflow
# or underflow that was disabled, then we have to force an overflow or
# underflow frame.
btst &ovfl_bit,FPSR_EXCEPT(%a6) # did overflow occur?
bne.b iea_op_exc_ovfl # yes
btst &unfl_bit,FPSR_EXCEPT(%a6) # did underflow occur?
bne.b iea_op_exc_unfl # yes
iea_op_exc_force:
mov.w (tbl_iea_except.b,%pc,%d0.w*2),2+FP_SRC(%a6)
bra.b iea_op_exit2 # exit with frestore
tbl_iea_except:
short 0xe002, 0xe006, 0xe004, 0xe005
short 0xe003, 0xe002, 0xe001, 0xe001
btst &0x7,(%sp) # is trace on?
bne.b iea_op_trace # yes
bra.l _fpsp_done # exit to os
#
# The opclass two instruction that took an "Unimplemented Effective Address"
# exception was being traced. Make the "current" PC the FPIAR and put it in
# the trace stack frame then jump to _real_trace().
#
# UNIMP EA FRAME TRACE FRAME
# ***************** *****************
# * 0x0 * 0x0f0 * * Current *
# ***************** * PC *
# * Current * *****************
# * PC * * 0x2 * 0x024 *
# ***************** *****************
# * SR * * Next *
# ***************** * PC *
# *****************
# * SR *
# *****************
iea_op_trace:
mov.l (%sp),-(%sp) # shift stack frame "down"
mov.w 0x8(%sp),0x4(%sp)
mov.w &0x2024,0x6(%sp) # stk fmt = 0x2; voff = 0x024
fmov.l %fpiar,0x8(%sp) # "Current PC" is in FPIAR
bra.l _real_trace
#########################################################################
iea_fmovm:
btst &14,%d0 # ctrl or data reg
beq.w iea_fmovm_ctrl
iea_fmovm_data:
btst &0x5,EXC_SR(%a6) # user or supervisor mode
bne.b iea_fmovm_data_s
iea_fmovm_data_u:
mov.l %usp,%a0
mov.l %a0,EXC_A7(%a6) # store current a7
bsr.l fmovm_dynamic # do dynamic fmovm
mov.l EXC_A7(%a6),%a0 # load possibly new a7
mov.l %a0,%usp # update usp
bra.w iea_fmovm_exit
# right now, d0 = the size.
# the data has been fetched from the supervisor stack, but we have not
# incremented the stack pointer by the appropriate number of bytes.
# do it here.
iea_fmovm_data_postinc:
btst &0x7,EXC_SR(%a6)
bne.b iea_fmovm_data_pi_trace
btst &0x7,EXC_SR(%a6) # is trace on?
bne.b iea_fmovm_trace # yes
mov.l EXC_EXTWPTR(%a6),EXC_PC(%a6) # set Next PC
unlk %a6 # unravel the frame
bra.l _fpsp_done # exit to os
#
# The control reg instruction that took an "Unimplemented Effective Address"
# exception was being traced. The "Current PC" for the trace frame is the
# PC stacked for Unimp EA. The "Next PC" is in EXC_EXTWPTR.
# After fixing the stack frame, jump to _real_trace().
#
# UNIMP EA FRAME TRACE FRAME
# ***************** *****************
# * 0x0 * 0x0f0 * * Current *
# ***************** * PC *
# * Current * *****************
# * PC * * 0x2 * 0x024 *
# ***************** *****************
# * SR * * Next *
# ***************** * PC *
# *****************
# * SR *
# *****************
# this ain't a pretty solution, but it works:
# -restore a6 (not with unlk)
# -shift stack frame down over where old a6 used to be
# -add LOCAL_SIZE to stack pointer
iea_fmovm_trace:
mov.l (%a6),%a6 # restore frame pointer
mov.w EXC_SR+LOCAL_SIZE(%sp),0x0+LOCAL_SIZE(%sp)
mov.l EXC_PC+LOCAL_SIZE(%sp),0x8+LOCAL_SIZE(%sp)
mov.l EXC_EXTWPTR+LOCAL_SIZE(%sp),0x2+LOCAL_SIZE(%sp)
mov.w &0x2024,0x6+LOCAL_SIZE(%sp) # stk fmt = 0x2; voff = 0x024
add.l &LOCAL_SIZE,%sp # clear stack frame
bra.l _real_trace
#########################################################################
# The FPU is disabled and so we should really have taken the "Line
# F Emulator" exception. So, here we create an 8-word stack frame
# from our 4-word stack frame. This means we must calculate the length
# of the faulting instruction to get the "next PC". This is trivial for
# immediate operands but requires some extra work for fmovm dynamic
# which can use most addressing modes.
iea_disabled:
mov.l (%sp)+,%d0 # restore d0
link %a6,&-LOCAL_SIZE # init stack frame
movm.l &0x0303,EXC_DREGS(%a6) # save d0-d1/a0-a1
# PC of instruction that took the exception is the PC in the frame
mov.l EXC_PC(%a6),EXC_EXTWPTR(%a6)
mov.l EXC_EXTWPTR(%a6),%a0 # fetch instruction addr
addq.l &0x4,EXC_EXTWPTR(%a6) # incr instruction ptr
bsr.l _imem_read_long # fetch the instruction words
mov.l %d0,EXC_OPWORD(%a6) # store OPWORD and EXTWORD
tst.w %d0 # is instr fmovm?
bmi.b iea_dis_fmovm # yes
# instruction is using an extended precision immediate operand. therefore,
# the total instruction length is 16 bytes.
iea_dis_immed:
mov.l &0x10,%d0 # 16 bytes of instruction
bra.b iea_dis_cont
iea_dis_fmovm:
btst &0xe,%d0 # is instr fmovm ctrl
bne.b iea_dis_fmovm_data # no
# the instruction is a fmovm.l with 2 or 3 registers.
bfextu %d0{&19:&3},%d1
mov.l &0xc,%d0
cmpi.b %d1,&0x7 # move all regs?
bne.b iea_dis_cont
addq.l &0x4,%d0
bra.b iea_dis_cont
# the instruction is an fmovm.x dynamic which can use many addressing
# modes and thus can have several different total instruction lengths.
# call fmovm_calc_ea which will go through the ea calc process and,
# as a by-product, will tell us how long the instruction is.
iea_dis_fmovm_data:
clr.l %d0
bsr.l fmovm_calc_ea
mov.l EXC_EXTWPTR(%a6),%d0
sub.l EXC_PC(%a6),%d0
iea_dis_cont:
mov.w %d0,EXC_VOFF(%a6) # store stack shift value
# here, we actually create the 8-word frame from the 4-word frame,
# with the "next PC" as additional info.
# the <ea> field is let as undefined.
subq.l &0x8,%sp # make room for new stack
mov.l %d0,-(%sp) # save d0
mov.w 0xc(%sp),0x4(%sp) # move SR
mov.l 0xe(%sp),0x6(%sp) # move Current PC
clr.l %d0
mov.w 0x12(%sp),%d0
mov.l 0x6(%sp),0x10(%sp) # move Current PC
add.l %d0,0x6(%sp) # make Next PC
mov.w &0x402c,0xa(%sp) # insert offset,frame format
mov.l (%sp)+,%d0 # restore d0
subq.w &0x8,%sp # make stack frame bigger
mov.l 0x8(%sp),(%sp) # store SR,hi(PC)
mov.w 0xc(%sp),0x4(%sp) # store lo(PC)
mov.w &0x4008,0x6(%sp) # store voff
mov.l 0x2(%sp),0x8(%sp) # store ea
mov.l &0x09428001,0xc(%sp) # store fslw
iea_acc_done:
btst &0x5,(%sp) # user or supervisor mode?
beq.b iea_acc_done2 # user
bset &0x2,0xd(%sp) # set supervisor TM bit
#########################################################################
# XDEF **************************************************************** #
# _fpsp_operr(): 060FPSP entry point for FP Operr exception. #
# #
# This handler should be the first code executed upon taking the #
# FP Operand Error exception in an operating system. #
# #
# XREF **************************************************************** #
# _imem_read_long() - read instruction longword #
# fix_skewed_ops() - adjust src operand in fsave frame #
# _real_operr() - "callout" to operating system operr handler #
# _dmem_write_{byte,word,long}() - store data to mem (opclass 3) #
# store_dreg_{b,w,l}() - store data to data regfile (opclass 3) #
# facc_out_{b,w,l}() - store to memory took access error (opcl 3) #
# #
# INPUT *************************************************************** #
# - The system stack contains the FP Operr exception frame #
# - The fsave frame contains the source operand #
# #
# OUTPUT ************************************************************** #
# No access error: #
# - The system stack is unchanged #
# - The fsave frame contains the adjusted src op for opclass 0,2 #
# #
# ALGORITHM *********************************************************** #
# In a system where the FP Operr exception is enabled, the goal #
# is to get to the handler specified at _real_operr(). But, on the 060, #
# for opclass zero and two instruction taking this exception, the #
# input operand in the fsave frame may be incorrect for some cases #
# and needs to be corrected. This handler calls fix_skewed_ops() to #
# do just this and then exits through _real_operr(). #
# For opclass 3 instructions, the 060 doesn't store the default #
# operr result out to memory or data register file as it should. #
# This code must emulate the move out before finally exiting through #
# _real_inex(). The move out, if to memory, is performed using #
# _mem_write() "callout" routines that may return a failing result. #
# In this special case, the handler must exit through facc_out() #
# which creates an access error stack frame from the current operr #
# stack frame. #
# #
#########################################################################
global _fpsp_operr
_fpsp_operr:
link.w %a6,&-LOCAL_SIZE # init stack frame
fsave FP_SRC(%a6) # grab the "busy" frame
movm.l &0x0303,EXC_DREGS(%a6) # save d0-d1/a0-a1
fmovm.l %fpcr,%fpsr,%fpiar,USER_FPCR(%a6) # save ctrl regs
fmovm.x &0xc0,EXC_FPREGS(%a6) # save fp0-fp1 on stack
# the FPIAR holds the "current PC" of the faulting instruction
mov.l USER_FPIAR(%a6),EXC_EXTWPTR(%a6)
btst &13,%d0 # is instr an fmove out?
bne.b foperr_out # fmove out
# here, we simply see if the operand in the fsave frame needs to be "unskewed".
# this would be the case for opclass two operations with a source infinity or
# denorm operand in the sgl or dbl format. NANs also become skewed, but can't
# cause an operr so we don't need to check for them here.
lea FP_SRC(%a6),%a0 # pass: ptr to src op
bsr.l fix_skewed_ops # fix src op
#
# the hardware does not save the default result to memory on enabled
# operand error exceptions. we do this here before passing control to
# the user operand error handler.
#
# byte, word, and long destination format operations can pass
# through here. we simply need to test the sign of the src
# operand and save the appropriate minimum or maximum integer value
# to the effective address as pointed to by the stacked effective address.
#
# although packed opclass three operations can take operand error
# exceptions, they won't pass through here since they are caught
# first by the unsupported data format exception handler. that handler
# sends them directly to _real_operr() if necessary.
#
foperr_out:
mov.w FP_SRC_EX(%a6),%d1 # fetch exponent
andi.w &0x7fff,%d1
cmpi.w %d1,&0x7fff
bne.b foperr_out_not_qnan
# the operand is either an infinity or a QNAN.
tst.l FP_SRC_LO(%a6)
bne.b foperr_out_qnan
mov.l FP_SRC_HI(%a6),%d1
andi.l &0x7fffffff,%d1
beq.b foperr_out_not_qnan
foperr_out_qnan:
mov.l FP_SRC_HI(%a6),L_SCR1(%a6)
bra.b foperr_out_jmp
foperr_out_jmp:
bfextu %d0{&19:&3},%d0 # extract dst format field
mov.b 1+EXC_OPWORD(%a6),%d1 # extract <ea> mode,reg
mov.w (tbl_operr.b,%pc,%d0.w*2),%a0
jmp (tbl_operr.b,%pc,%a0)
tbl_operr:
short foperr_out_l - tbl_operr # long word integer
short tbl_operr - tbl_operr # sgl prec shouldn't happen
short tbl_operr - tbl_operr # ext prec shouldn't happen
short foperr_exit - tbl_operr # packed won't enter here
short foperr_out_w - tbl_operr # word integer
short tbl_operr - tbl_operr # dbl prec shouldn't happen
short foperr_out_b - tbl_operr # byte integer
short tbl_operr - tbl_operr # packed won't enter here
foperr_out_b:
mov.b L_SCR1(%a6),%d0 # load positive default result
cmpi.b %d1,&0x7 # is <ea> mode a data reg?
ble.b foperr_out_b_save_dn # yes
mov.l EXC_EA(%a6),%a0 # pass: <ea> of default result
bsr.l _dmem_write_byte # write the default result
tst.l %d1 # did dstore fail?
bne.l facc_out_b # yes
bra.w foperr_exit
foperr_out_b_save_dn:
andi.w &0x0007,%d1
bsr.l store_dreg_b # store result to regfile
bra.w foperr_exit
foperr_out_w:
mov.w L_SCR1(%a6),%d0 # load positive default result
cmpi.b %d1,&0x7 # is <ea> mode a data reg?
ble.b foperr_out_w_save_dn # yes
mov.l EXC_EA(%a6),%a0 # pass: <ea> of default result
bsr.l _dmem_write_word # write the default result
tst.l %d1 # did dstore fail?
bne.l facc_out_w # yes
bra.w foperr_exit
foperr_out_w_save_dn:
andi.w &0x0007,%d1
bsr.l store_dreg_w # store result to regfile
bra.w foperr_exit
foperr_out_l:
mov.l L_SCR1(%a6),%d0 # load positive default result
cmpi.b %d1,&0x7 # is <ea> mode a data reg?
ble.b foperr_out_l_save_dn # yes
mov.l EXC_EA(%a6),%a0 # pass: <ea> of default result
bsr.l _dmem_write_long # write the default result
tst.l %d1 # did dstore fail?
bne.l facc_out_l # yes
bra.w foperr_exit
foperr_out_l_save_dn:
andi.w &0x0007,%d1
bsr.l store_dreg_l # store result to regfile
bra.w foperr_exit
#########################################################################
# XDEF **************************************************************** #
# _fpsp_snan(): 060FPSP entry point for FP SNAN exception. #
# #
# This handler should be the first code executed upon taking the #
# FP Signalling NAN exception in an operating system. #
# #
# XREF **************************************************************** #
# _imem_read_long() - read instruction longword #
# fix_skewed_ops() - adjust src operand in fsave frame #
# _real_snan() - "callout" to operating system SNAN handler #
# _dmem_write_{byte,word,long}() - store data to mem (opclass 3) #
# store_dreg_{b,w,l}() - store data to data regfile (opclass 3) #
# facc_out_{b,w,l,d,x}() - store to mem took acc error (opcl 3) #
# _calc_ea_fout() - fix An if <ea> is -() or ()+; also get <ea> #
# #
# INPUT *************************************************************** #
# - The system stack contains the FP SNAN exception frame #
# - The fsave frame contains the source operand #
# #
# OUTPUT ************************************************************** #
# No access error: #
# - The system stack is unchanged #
# - The fsave frame contains the adjusted src op for opclass 0,2 #
# #
# ALGORITHM *********************************************************** #
# In a system where the FP SNAN exception is enabled, the goal #
# is to get to the handler specified at _real_snan(). But, on the 060, #
# for opclass zero and two instructions taking this exception, the #
# input operand in the fsave frame may be incorrect for some cases #
# and needs to be corrected. This handler calls fix_skewed_ops() to #
# do just this and then exits through _real_snan(). #
# For opclass 3 instructions, the 060 doesn't store the default #
# SNAN result out to memory or data register file as it should. #
# This code must emulate the move out before finally exiting through #
# _real_snan(). The move out, if to memory, is performed using #
# _mem_write() "callout" routines that may return a failing result. #
# In this special case, the handler must exit through facc_out() #
# which creates an access error stack frame from the current SNAN #
# stack frame. #
# For the case of an extended precision opclass 3 instruction, #
# if the effective addressing mode was -() or ()+, then the address #
# register must get updated by calling _calc_ea_fout(). If the <ea> #
# was -(a7) from supervisor mode, then the exception frame currently #
# on the system stack must be carefully moved "down" to make room #
# for the operand being moved. #
# #
#########################################################################
global _fpsp_snan
_fpsp_snan:
link.w %a6,&-LOCAL_SIZE # init stack frame
fsave FP_SRC(%a6) # grab the "busy" frame
movm.l &0x0303,EXC_DREGS(%a6) # save d0-d1/a0-a1
fmovm.l %fpcr,%fpsr,%fpiar,USER_FPCR(%a6) # save ctrl regs
fmovm.x &0xc0,EXC_FPREGS(%a6) # save fp0-fp1 on stack
# the FPIAR holds the "current PC" of the faulting instruction
mov.l USER_FPIAR(%a6),EXC_EXTWPTR(%a6)
btst &13,%d0 # is instr an fmove out?
bne.w fsnan_out # fmove out
# here, we simply see if the operand in the fsave frame needs to be "unskewed".
# this would be the case for opclass two operations with a source infinity or
# denorm operand in the sgl or dbl format. NANs also become skewed and must be
# fixed here.
lea FP_SRC(%a6),%a0 # pass: ptr to src op
bsr.l fix_skewed_ops # fix src op
#
# the hardware does not save the default result to memory on enabled
# snan exceptions. we do this here before passing control to
# the user snan handler.
#
# byte, word, long, and packed destination format operations can pass
# through here. since packed format operations already were handled by
# fpsp_unsupp(), then we need to do nothing else for them here.
# for byte, word, and long, we simply need to test the sign of the src
# operand and save the appropriate minimum or maximum integer value
# to the effective address as pointed to by the stacked effective address.
#
fsnan_out:
bfextu %d0{&19:&3},%d0 # extract dst format field
mov.b 1+EXC_OPWORD(%a6),%d1 # extract <ea> mode,reg
mov.w (tbl_snan.b,%pc,%d0.w*2),%a0
jmp (tbl_snan.b,%pc,%a0)
tbl_snan:
short fsnan_out_l - tbl_snan # long word integer
short fsnan_out_s - tbl_snan # sgl prec shouldn't happen
short fsnan_out_x - tbl_snan # ext prec shouldn't happen
short tbl_snan - tbl_snan # packed needs no help
short fsnan_out_w - tbl_snan # word integer
short fsnan_out_d - tbl_snan # dbl prec shouldn't happen
short fsnan_out_b - tbl_snan # byte integer
short tbl_snan - tbl_snan # packed needs no help
fsnan_out_b:
mov.b FP_SRC_HI(%a6),%d0 # load upper byte of SNAN
bset &6,%d0 # set SNAN bit
cmpi.b %d1,&0x7 # is <ea> mode a data reg?
ble.b fsnan_out_b_dn # yes
mov.l EXC_EA(%a6),%a0 # pass: <ea> of default result
bsr.l _dmem_write_byte # write the default result
tst.l %d1 # did dstore fail?
bne.l facc_out_b # yes
bra.w fsnan_exit
fsnan_out_b_dn:
andi.w &0x0007,%d1
bsr.l store_dreg_b # store result to regfile
bra.w fsnan_exit
fsnan_out_w:
mov.w FP_SRC_HI(%a6),%d0 # load upper word of SNAN
bset &14,%d0 # set SNAN bit
cmpi.b %d1,&0x7 # is <ea> mode a data reg?
ble.b fsnan_out_w_dn # yes
mov.l EXC_EA(%a6),%a0 # pass: <ea> of default result
bsr.l _dmem_write_word # write the default result
tst.l %d1 # did dstore fail?
bne.l facc_out_w # yes
bra.w fsnan_exit
fsnan_out_w_dn:
andi.w &0x0007,%d1
bsr.l store_dreg_w # store result to regfile
bra.w fsnan_exit
fsnan_out_l:
mov.l FP_SRC_HI(%a6),%d0 # load upper longword of SNAN
bset &30,%d0 # set SNAN bit
cmpi.b %d1,&0x7 # is <ea> mode a data reg?
ble.b fsnan_out_l_dn # yes
mov.l EXC_EA(%a6),%a0 # pass: <ea> of default result
bsr.l _dmem_write_long # write the default result
tst.l %d1 # did dstore fail?
bne.l facc_out_l # yes
bra.w fsnan_exit
fsnan_out_l_dn:
andi.w &0x0007,%d1
bsr.l store_dreg_l # store result to regfile
bra.w fsnan_exit
fsnan_out_s:
cmpi.b %d1,&0x7 # is <ea> mode a data reg?
ble.b fsnan_out_d_dn # yes
mov.l FP_SRC_EX(%a6),%d0 # fetch SNAN sign
andi.l &0x80000000,%d0 # keep sign
ori.l &0x7fc00000,%d0 # insert new exponent,SNAN bit
mov.l FP_SRC_HI(%a6),%d1 # load mantissa
lsr.l &0x8,%d1 # shift mantissa for sgl
or.l %d1,%d0 # create sgl SNAN
mov.l EXC_EA(%a6),%a0 # pass: <ea> of default result
bsr.l _dmem_write_long # write the default result
tst.l %d1 # did dstore fail?
bne.l facc_out_l # yes
bra.w fsnan_exit
fsnan_out_d_dn:
mov.l FP_SRC_EX(%a6),%d0 # fetch SNAN sign
andi.l &0x80000000,%d0 # keep sign
ori.l &0x7fc00000,%d0 # insert new exponent,SNAN bit
mov.l %d1,-(%sp)
mov.l FP_SRC_HI(%a6),%d1 # load mantissa
lsr.l &0x8,%d1 # shift mantissa for sgl
or.l %d1,%d0 # create sgl SNAN
mov.l (%sp)+,%d1
andi.w &0x0007,%d1
bsr.l store_dreg_l # store result to regfile
bra.w fsnan_exit
fsnan_out_d:
mov.l FP_SRC_EX(%a6),%d0 # fetch SNAN sign
andi.l &0x80000000,%d0 # keep sign
ori.l &0x7ff80000,%d0 # insert new exponent,SNAN bit
mov.l FP_SRC_HI(%a6),%d1 # load hi mantissa
mov.l %d0,FP_SCR0_EX(%a6) # store to temp space
mov.l &11,%d0 # load shift amt
lsr.l %d0,%d1
or.l %d1,FP_SCR0_EX(%a6) # create dbl hi
mov.l FP_SRC_HI(%a6),%d1 # load hi mantissa
andi.l &0x000007ff,%d1
ror.l %d0,%d1
mov.l %d1,FP_SCR0_HI(%a6) # store to temp space
mov.l FP_SRC_LO(%a6),%d1 # load lo mantissa
lsr.l %d0,%d1
or.l %d1,FP_SCR0_HI(%a6) # create dbl lo
lea FP_SCR0(%a6),%a0 # pass: ptr to operand
mov.l EXC_EA(%a6),%a1 # pass: dst addr
movq.l &0x8,%d0 # pass: size of 8 bytes
bsr.l _dmem_write # write the default result
tst.l %d1 # did dstore fail?
bne.l facc_out_d # yes
bra.w fsnan_exit
# for extended precision, if the addressing mode is pre-decrement or
# post-increment, then the address register did not get updated.
# in addition, for pre-decrement, the stacked <ea> is incorrect.
fsnan_out_x:
clr.b SPCOND_FLG(%a6) # clear special case flag
#########################################################################
# XDEF **************************************************************** #
# _fpsp_inex(): 060FPSP entry point for FP Inexact exception. #
# #
# This handler should be the first code executed upon taking the #
# FP Inexact exception in an operating system. #
# #
# XREF **************************************************************** #
# _imem_read_long() - read instruction longword #
# fix_skewed_ops() - adjust src operand in fsave frame #
# set_tag_x() - determine optype of src/dst operands #
# store_fpreg() - store opclass 0 or 2 result to FP regfile #
# unnorm_fix() - change UNNORM operands to NORM or ZERO #
# load_fpn2() - load dst operand from FP regfile #
# smovcr() - emulate an "fmovcr" instruction #
# fout() - emulate an opclass 3 instruction #
# tbl_unsupp - add of table of emulation routines for opclass 0,2 #
# _real_inex() - "callout" to operating system inexact handler #
# #
# INPUT *************************************************************** #
# - The system stack contains the FP Inexact exception frame #
# - The fsave frame contains the source operand #
# #
# OUTPUT ************************************************************** #
# - The system stack is unchanged #
# - The fsave frame contains the adjusted src op for opclass 0,2 #
# #
# ALGORITHM *********************************************************** #
# In a system where the FP Inexact exception is enabled, the goal #
# is to get to the handler specified at _real_inex(). But, on the 060, #
# for opclass zero and two instruction taking this exception, the #
# hardware doesn't store the correct result to the destination FP #
# register as did the '040 and '881/2. This handler must emulate the #
# instruction in order to get this value and then store it to the #
# correct register before calling _real_inex(). #
# For opclass 3 instructions, the 060 doesn't store the default #
# inexact result out to memory or data register file as it should. #
# This code must emulate the move out by calling fout() before finally #
# exiting through _real_inex(). #
# #
#########################################################################
global _fpsp_inex
_fpsp_inex:
link.w %a6,&-LOCAL_SIZE # init stack frame
fsave FP_SRC(%a6) # grab the "busy" frame
movm.l &0x0303,EXC_DREGS(%a6) # save d0-d1/a0-a1
fmovm.l %fpcr,%fpsr,%fpiar,USER_FPCR(%a6) # save ctrl regs
fmovm.x &0xc0,EXC_FPREGS(%a6) # save fp0-fp1 on stack
# the FPIAR holds the "current PC" of the faulting instruction
mov.l USER_FPIAR(%a6),EXC_EXTWPTR(%a6)
btst &13,%d0 # is instr an fmove out?
bne.w finex_out # fmove out
# the hardware, for "fabs" and "fneg" w/ a long source format, puts the
# longword integer directly into the upper longword of the mantissa along
# w/ an exponent value of 0x401e. we convert this to extended precision here.
bfextu %d0{&19:&3},%d0 # fetch instr size
bne.b finex_cont # instr size is not long
cmpi.w FP_SRC_EX(%a6),&0x401e # is exponent 0x401e?
bne.b finex_cont # no
fmov.l &0x0,%fpcr
fmov.l FP_SRC_HI(%a6),%fp0 # load integer src
fmov.x %fp0,FP_SRC(%a6) # store integer as extended precision
mov.w &0xe001,0x2+FP_SRC(%a6)
finex_cont:
lea FP_SRC(%a6),%a0 # pass: ptr to src op
bsr.l fix_skewed_ops # fix src op
# Here, we zero the ccode and exception byte field since we're going to
# emulate the whole instruction. Notice, though, that we don't kill the
# INEX1 bit. This is because a packed op has long since been converted
# to extended before arriving here. Therefore, we need to retain the
# INEX1 bit from when the operand was first converted.
andi.l &0x00ff01ff,USER_FPSR(%a6) # zero all but accured field
fmov.l &0x0,%fpcr # zero current control regs
fmov.l &0x0,%fpsr
bfextu EXC_EXTWORD(%a6){&0:&6},%d1 # extract upper 6 of cmdreg
cmpi.b %d1,&0x17 # is op an fmovecr?
beq.w finex_fmovcr # yes
lea FP_SRC(%a6),%a0 # pass: ptr to src op
bsr.l set_tag_x # tag the operand type
mov.b %d0,STAG(%a6) # maybe NORM,DENORM
# bits four and five of the fp extension word separate the monadic and dyadic
# operations that can pass through fpsp_inex(). remember that fcmp and ftst
# will never take this exception, but fsincos will.
btst &0x5,1+EXC_CMDREG(%a6) # is operation monadic or dyadic?
beq.b finex_extract # monadic
btst &0x4,1+EXC_CMDREG(%a6) # is operation an fsincos?
bne.b finex_extract # yes
lea FP_DST(%a6),%a0 # pass: ptr to dst op
bsr.l set_tag_x # tag the operand type
cmpi.b %d0,&UNNORM # is operand an UNNORM?
bne.b finex_op2_done # no
bsr.l unnorm_fix # yes; convert to NORM,DENORM,or ZERO
finex_op2_done:
mov.b %d0,DTAG(%a6) # save dst optype tag
#
# the hardware does not save the default result to memory on enabled
# inexact exceptions. we do this here before passing control to
# the user inexact handler.
#
# byte, word, and long destination format operations can pass
# through here. so can double and single precision.
# although packed opclass three operations can take inexact
# exceptions, they won't pass through here since they are caught
# first by the unsupported data format exception handler. that handler
# sends them directly to _real_inex() if necessary.
#
finex_out:
andi.l &0xffff00ff,USER_FPSR(%a6) # zero exception field
lea FP_SRC(%a6),%a0 # pass ptr to src operand
bsr.l fout # store the default result
bra.b finex_exit
#########################################################################
# XDEF **************************************************************** #
# _fpsp_dz(): 060FPSP entry point for FP DZ exception. #
# #
# This handler should be the first code executed upon taking #
# the FP DZ exception in an operating system. #
# #
# XREF **************************************************************** #
# _imem_read_long() - read instruction longword from memory #
# fix_skewed_ops() - adjust fsave operand #
# _real_dz() - "callout" exit point from FP DZ handler #
# #
# INPUT *************************************************************** #
# - The system stack contains the FP DZ exception stack. #
# - The fsave frame contains the source operand. #
# #
# OUTPUT ************************************************************** #
# - The system stack contains the FP DZ exception stack. #
# - The fsave frame contains the adjusted source operand. #
# #
# ALGORITHM *********************************************************** #
# In a system where the DZ exception is enabled, the goal is to #
# get to the handler specified at _real_dz(). But, on the 060, when the #
# exception is taken, the input operand in the fsave state frame may #
# be incorrect for some cases and need to be adjusted. So, this package #
# adjusts the operand using fix_skewed_ops() and then branches to #
# _real_dz(). #
# #
#########################################################################
global _fpsp_dz
_fpsp_dz:
link.w %a6,&-LOCAL_SIZE # init stack frame
fsave FP_SRC(%a6) # grab the "busy" frame
movm.l &0x0303,EXC_DREGS(%a6) # save d0-d1/a0-a1
fmovm.l %fpcr,%fpsr,%fpiar,USER_FPCR(%a6) # save ctrl regs
fmovm.x &0xc0,EXC_FPREGS(%a6) # save fp0-fp1 on stack
# the FPIAR holds the "current PC" of the faulting instruction
mov.l USER_FPIAR(%a6),EXC_EXTWPTR(%a6)
# here, we simply see if the operand in the fsave frame needs to be "unskewed".
# this would be the case for opclass two operations with a source zero
# in the sgl or dbl format.
lea FP_SRC(%a6),%a0 # pass: ptr to src op
bsr.l fix_skewed_ops # fix src op
#########################################################################
# XDEF **************************************************************** #
# _fpsp_fline(): 060FPSP entry point for "Line F emulator" #
# exception when the "reduced" version of the #
# FPSP is implemented that does not emulate #
# FP unimplemented instructions. #
# #
# This handler should be the first code executed upon taking a #
# "Line F Emulator" exception in an operating system integrating #
# the reduced version of 060FPSP. #
# #
# XREF **************************************************************** #
# _real_fpu_disabled() - Handle "FPU disabled" exceptions #
# _real_fline() - Handle all other cases (treated equally) #
# #
# INPUT *************************************************************** #
# - The system stack contains a "Line F Emulator" exception #
# stack frame. #
# #
# OUTPUT ************************************************************** #
# - The system stack is unchanged. #
# #
# ALGORITHM *********************************************************** #
# When a "Line F Emulator" exception occurs in a system where #
# "FPU Unimplemented" instructions will not be emulated, the exception #
# can occur because then FPU is disabled or the instruction is to be #
# classifed as "Line F". This module determines which case exists and #
# calls the appropriate "callout". #
# #
#########################################################################
global _fpsp_fline
_fpsp_fline:
# check to see if the FPU is disabled. if so, jump to the OS entry
# point for that condition.
cmpi.w 0x6(%sp),&0x402c
beq.l _real_fpu_disabled
bra.l _real_fline
#########################################################################
# XDEF **************************************************************** #
# _dcalc_ea(): calc correct <ea> from <ea> stacked on exception #
# #
# XREF **************************************************************** #
# inc_areg() - increment an address register #
# dec_areg() - decrement an address register #
# #
# INPUT *************************************************************** #
# d0 = number of bytes to adjust <ea> by #
# #
# OUTPUT ************************************************************** #
# None #
# #
# ALGORITHM *********************************************************** #
# "Dummy" CALCulate Effective Address: #
# The stacked <ea> for FP unimplemented instructions and opclass #
# two packed instructions is correct with the exception of... #
# #
# 1) -(An) : The register is not updated regardless of size. #
# Also, for extended precision and packed, the #
# stacked <ea> value is 8 bytes too big #
# 2) (An)+ : The register is not updated. #
# 3) #<data> : The upper longword of the immediate operand is #
# stacked b,w,l and s sizes are completely stacked. #
# d,x, and p are not. #
# #
#########################################################################
global _dcalc_ea
_dcalc_ea:
mov.l %d0, %a0 # move # bytes to %a0
mov.b 1+EXC_OPWORD(%a6), %d0 # fetch opcode word
mov.l %d0, %d1 # make a copy
andi.w &0x38, %d0 # extract mode field
andi.l &0x7, %d1 # extract reg field
# need to set immediate data flag here since we'll need to do
# an imem_read to fetch this later.
dcea_imm:
mov.b &immed_flg,SPCOND_FLG(%a6)
lea ([USER_FPIAR,%a6],0x4),%a0 # no; return <ea>
rts
# here, the <ea> is stacked correctly. however, we must update the
# address register...
dcea_pi:
mov.l %a0,%d0 # pass amt to inc by
bsr.l inc_areg # inc addr register
mov.l EXC_EA(%a6),%a0 # stacked <ea> is correct
rts
# the <ea> is stacked correctly for all but extended and packed which
# the <ea>s are 8 bytes too large.
# it would make no sense to have a pre-decrement to a7 in supervisor
# mode so we don't even worry about this tricky case here : )
dcea_pd:
mov.l %a0,%d0 # pass amt to dec by
bsr.l dec_areg # dec addr register
mov.l EXC_EA(%a6),%a0 # stacked <ea> is correct
cmpi.b %d0,&0xc # is opsize ext or packed?
beq.b dcea_pd2 # yes
rts
dcea_pd2:
sub.l &0x8,%a0 # correct <ea>
mov.l %a0,EXC_EA(%a6) # put correct <ea> on stack
rts
#########################################################################
# XDEF **************************************************************** #
# _calc_ea_fout(): calculate correct stacked <ea> for extended #
# and packed data opclass 3 operations. #
# #
# XREF **************************************************************** #
# None #
# #
# INPUT *************************************************************** #
# None #
# #
# OUTPUT ************************************************************** #
# a0 = return correct effective address #
# #
# ALGORITHM *********************************************************** #
# For opclass 3 extended and packed data operations, the <ea> #
# stacked for the exception is incorrect for -(an) and (an)+ addressing #
# modes. Also, while we're at it, the index register itself must get #
# updated. #
# So, for -(an), we must subtract 8 off of the stacked <ea> value #
# and return that value as the correct <ea> and store that value in An. #
# For (an)+, the stacked <ea> is correct but we must adjust An by +12. #
# #
#########################################################################
# This calc_ea is currently used to retrieve the correct <ea>
# for fmove outs of type extended and packed.
global _calc_ea_fout
_calc_ea_fout:
mov.b 1+EXC_OPWORD(%a6),%d0 # fetch opcode word
mov.l %d0,%d1 # make a copy
andi.w &0x38,%d0 # extract mode field
andi.l &0x7,%d1 # extract reg field
mov.l EXC_EA(%a6),%a0 # stacked <ea> is correct
rts
# (An)+ : extended and packed fmove out
# : stacked <ea> is correct
# : "An" not updated
ceaf_pi:
mov.w (tbl_ceaf_pi.b,%pc,%d1.w*2),%d1
mov.l EXC_EA(%a6),%a0
jmp (tbl_ceaf_pi.b,%pc,%d1.w*1)
swbeg &0x8
tbl_ceaf_pi:
short ceaf_pi0 - tbl_ceaf_pi
short ceaf_pi1 - tbl_ceaf_pi
short ceaf_pi2 - tbl_ceaf_pi
short ceaf_pi3 - tbl_ceaf_pi
short ceaf_pi4 - tbl_ceaf_pi
short ceaf_pi5 - tbl_ceaf_pi
short ceaf_pi6 - tbl_ceaf_pi
short ceaf_pi7 - tbl_ceaf_pi
# -(An) : extended and packed fmove out
# : stacked <ea> = actual <ea> + 8
# : "An" not updated
ceaf_pd:
mov.w (tbl_ceaf_pd.b,%pc,%d1.w*2),%d1
mov.l EXC_EA(%a6),%a0
sub.l &0x8,%a0
sub.l &0x8,EXC_EA(%a6)
jmp (tbl_ceaf_pd.b,%pc,%d1.w*1)
swbeg &0x8
tbl_ceaf_pd:
short ceaf_pd0 - tbl_ceaf_pd
short ceaf_pd1 - tbl_ceaf_pd
short ceaf_pd2 - tbl_ceaf_pd
short ceaf_pd3 - tbl_ceaf_pd
short ceaf_pd4 - tbl_ceaf_pd
short ceaf_pd5 - tbl_ceaf_pd
short ceaf_pd6 - tbl_ceaf_pd
short ceaf_pd7 - tbl_ceaf_pd
#
# This table holds the offsets of the emulation routines for each individual
# math operation relative to the address of this table. Included are
# routines like fadd/fmul/fabs. The transcendentals ARE NOT. This is because
# this table is for the version if the 060FPSP without transcendentals.
# The location within the table is determined by the extension bits of the
# operation longword.
#
swbeg &109
tbl_unsupp:
long fin - tbl_unsupp # 00: fmove
long fint - tbl_unsupp # 01: fint
long tbl_unsupp - tbl_unsupp # 02: fsinh
long fintrz - tbl_unsupp # 03: fintrz
long fsqrt - tbl_unsupp # 04: fsqrt
long tbl_unsupp - tbl_unsupp
long tbl_unsupp - tbl_unsupp # 06: flognp1
long tbl_unsupp - tbl_unsupp
long tbl_unsupp - tbl_unsupp # 08: fetoxm1
long tbl_unsupp - tbl_unsupp # 09: ftanh
long tbl_unsupp - tbl_unsupp # 0a: fatan
long tbl_unsupp - tbl_unsupp
long tbl_unsupp - tbl_unsupp # 0c: fasin
long tbl_unsupp - tbl_unsupp # 0d: fatanh
long tbl_unsupp - tbl_unsupp # 0e: fsin
long tbl_unsupp - tbl_unsupp # 0f: ftan
long tbl_unsupp - tbl_unsupp # 10: fetox
long tbl_unsupp - tbl_unsupp # 11: ftwotox
long tbl_unsupp - tbl_unsupp # 12: ftentox
long tbl_unsupp - tbl_unsupp
long tbl_unsupp - tbl_unsupp # 14: flogn
long tbl_unsupp - tbl_unsupp # 15: flog10
long tbl_unsupp - tbl_unsupp # 16: flog2
long tbl_unsupp - tbl_unsupp
long fabs - tbl_unsupp # 18: fabs
long tbl_unsupp - tbl_unsupp # 19: fcosh
long fneg - tbl_unsupp # 1a: fneg
long tbl_unsupp - tbl_unsupp
long tbl_unsupp - tbl_unsupp # 1c: facos
long tbl_unsupp - tbl_unsupp # 1d: fcos
long tbl_unsupp - tbl_unsupp # 1e: fgetexp
long tbl_unsupp - tbl_unsupp # 1f: fgetman
long fdiv - tbl_unsupp # 20: fdiv
long tbl_unsupp - tbl_unsupp # 21: fmod
long fadd - tbl_unsupp # 22: fadd
long fmul - tbl_unsupp # 23: fmul
long fsgldiv - tbl_unsupp # 24: fsgldiv
long tbl_unsupp - tbl_unsupp # 25: frem
long tbl_unsupp - tbl_unsupp # 26: fscale
long fsglmul - tbl_unsupp # 27: fsglmul
long fsub - tbl_unsupp # 28: fsub
long tbl_unsupp - tbl_unsupp
long tbl_unsupp - tbl_unsupp
long tbl_unsupp - tbl_unsupp
long tbl_unsupp - tbl_unsupp
long tbl_unsupp - tbl_unsupp
long tbl_unsupp - tbl_unsupp
long tbl_unsupp - tbl_unsupp
long tbl_unsupp - tbl_unsupp # 30: fsincos
long tbl_unsupp - tbl_unsupp # 31: fsincos
long tbl_unsupp - tbl_unsupp # 32: fsincos
long tbl_unsupp - tbl_unsupp # 33: fsincos
long tbl_unsupp - tbl_unsupp # 34: fsincos
long tbl_unsupp - tbl_unsupp # 35: fsincos
long tbl_unsupp - tbl_unsupp # 36: fsincos
long tbl_unsupp - tbl_unsupp # 37: fsincos
long fcmp - tbl_unsupp # 38: fcmp
long tbl_unsupp - tbl_unsupp
long ftst - tbl_unsupp # 3a: ftst
long tbl_unsupp - tbl_unsupp
long tbl_unsupp - tbl_unsupp
long tbl_unsupp - tbl_unsupp
long tbl_unsupp - tbl_unsupp
long tbl_unsupp - tbl_unsupp
long fsin - tbl_unsupp # 40: fsmove
long fssqrt - tbl_unsupp # 41: fssqrt
long tbl_unsupp - tbl_unsupp
long tbl_unsupp - tbl_unsupp
long fdin - tbl_unsupp # 44: fdmove
long fdsqrt - tbl_unsupp # 45: fdsqrt
long tbl_unsupp - tbl_unsupp
long tbl_unsupp - tbl_unsupp
long tbl_unsupp - tbl_unsupp
long tbl_unsupp - tbl_unsupp
long tbl_unsupp - tbl_unsupp
long tbl_unsupp - tbl_unsupp
long tbl_unsupp - tbl_unsupp
long tbl_unsupp - tbl_unsupp
long tbl_unsupp - tbl_unsupp
long tbl_unsupp - tbl_unsupp
long tbl_unsupp - tbl_unsupp
long tbl_unsupp - tbl_unsupp
long tbl_unsupp - tbl_unsupp
long tbl_unsupp - tbl_unsupp
long tbl_unsupp - tbl_unsupp
long tbl_unsupp - tbl_unsupp
long tbl_unsupp - tbl_unsupp
long tbl_unsupp - tbl_unsupp
long fsabs - tbl_unsupp # 58: fsabs
long tbl_unsupp - tbl_unsupp
long fsneg - tbl_unsupp # 5a: fsneg
long tbl_unsupp - tbl_unsupp
long fdabs - tbl_unsupp # 5c: fdabs
long tbl_unsupp - tbl_unsupp
long fdneg - tbl_unsupp # 5e: fdneg
long tbl_unsupp - tbl_unsupp
long fsdiv - tbl_unsupp # 60: fsdiv
long tbl_unsupp - tbl_unsupp
long fsadd - tbl_unsupp # 62: fsadd
long fsmul - tbl_unsupp # 63: fsmul
long fddiv - tbl_unsupp # 64: fddiv
long tbl_unsupp - tbl_unsupp
long fdadd - tbl_unsupp # 66: fdadd
long fdmul - tbl_unsupp # 67: fdmul
long fssub - tbl_unsupp # 68: fssub
long tbl_unsupp - tbl_unsupp
long tbl_unsupp - tbl_unsupp
long tbl_unsupp - tbl_unsupp
long fdsub - tbl_unsupp # 6c: fdsub
#################################################
# Add this here so non-fp modules can compile.
# (smovcr is called from fpsp_inex.)
global smovcr
smovcr:
bra.b smovcr
#########################################################################
# XDEF **************************************************************** #
# fmovm_dynamic(): emulate "fmovm" dynamic instruction #
# #
# XREF **************************************************************** #
# fetch_dreg() - fetch data register #
# {i,d,}mem_read() - fetch data from memory #
# _mem_write() - write data to memory #
# iea_iacc() - instruction memory access error occurred #
# iea_dacc() - data memory access error occurred #
# restore() - restore An index regs if access error occurred #
# #
# INPUT *************************************************************** #
# None #
# #
# OUTPUT ************************************************************** #
# If instr is "fmovm Dn,-(A7)" from supervisor mode, #
# d0 = size of dump #
# d1 = Dn #
# Else if instruction access error, #
# d0 = FSLW #
# Else if data access error, #
# d0 = FSLW #
# a0 = address of fault #
# Else #
# none. #
# #
# ALGORITHM *********************************************************** #
# The effective address must be calculated since this is entered #
# from an "Unimplemented Effective Address" exception handler. So, we #
# have our own fcalc_ea() routine here. If an access error is flagged #
# by a _{i,d,}mem_read() call, we must exit through the special #
# handler. #
# The data register is determined and its value loaded to get the #
# string of FP registers affected. This value is used as an index into #
# a lookup table such that we can determine the number of bytes #
# involved. #
# If the instruction is "fmovm.x <ea>,Dn", a _mem_read() is used #
# to read in all FP values. Again, _mem_read() may fail and require a #
# special exit. #
# If the instruction is "fmovm.x DN,<ea>", a _mem_write() is used #
# to write all FP values. _mem_write() may also fail. #
# If the instruction is "fmovm.x DN,-(a7)" from supervisor mode, #
# then we return the size of the dump and the string to the caller #
# so that the move can occur outside of this routine. This special #
# case is required so that moves to the system stack are handled #
# correctly. #
# #
# DYNAMIC: #
# fmovm.x dn, <ea> #
# fmovm.x <ea>, dn #
# #
# <WORD 1> <WORD2> #
# 1111 0010 00 |<ea>| 11@& 1000 0$$$ 0000 #
# #
# & = (0): predecrement addressing mode #
# (1): postincrement or control addressing mode #
# @ = (0): move listed regs from memory to the FPU #
# (1): move listed regs from the FPU to memory #
# $$$ : index of data register holding reg select mask #
# #
# NOTES: #
# If the data register holds a zero, then the #
# instruction is a nop. #
# #
#########################################################################
global fmovm_dynamic
fmovm_dynamic:
# extract the data register in which the bit string resides...
mov.b 1+EXC_EXTWORD(%a6),%d1 # fetch extword
andi.w &0x70,%d1 # extract reg bits
lsr.b &0x4,%d1 # shift into lo bits
# fetch the bit string into d0...
bsr.l fetch_dreg # fetch reg string
# if the bit string is a zero, then the operation is a no-op
# but, make sure that we've calculated ea and advanced the opword pointer
beq.w fmovm_data_done
# separate move ins from move outs...
btst &0x5,EXC_EXTWORD(%a6) # is it a move in or out?
beq.w fmovm_data_in # it's a move out
#############
# MOVE OUT: #
#############
fmovm_data_out:
btst &0x4,EXC_EXTWORD(%a6) # control or predecrement?
bne.w fmovm_out_ctrl # control
############################
fmovm_out_predec:
# for predecrement mode, the bit string is the opposite of both control
# operations and postincrement mode. (bit7 = FP7 ... bit0 = FP0)
# here, we convert it to be just like the others...
mov.b (tbl_fmovm_convert.w,%pc,%d1.w*1),%d1
btst &0x5,EXC_SR(%a6) # user or supervisor mode?
beq.b fmovm_out_ctrl # user
fmovm_out_predec_s:
cmpi.b SPCOND_FLG(%a6),&mda7_flg # is <ea> mode -(a7)?
bne.b fmovm_out_ctrl
# the operation was unfortunately an: fmovm.x dn,-(sp)
# called from supervisor mode.
# we're also passing "size" and "strg" back to the calling routine
rts
############################
fmovm_out_ctrl:
mov.l %a0,%a1 # move <ea> to a1
sub.l %d0,%sp # subtract size of dump
lea (%sp),%a0
tst.b %d1 # should FP0 be moved?
bpl.b fmovm_out_ctrl_fp1 # no
global fmovm_calc_ea
###############################################
# _fmovm_calc_ea: calculate effective address #
###############################################
fmovm_calc_ea:
mov.l %d0,%a0 # move # bytes to a0
# currently, MODE and REG are taken from the EXC_OPWORD. this could be
# easily changed if they were inputs passed in registers.
mov.w EXC_OPWORD(%a6),%d0 # fetch opcode word
mov.w %d0,%d1 # make a copy
andi.w &0x3f,%d0 # extract mode field
andi.l &0x7,%d1 # extract reg field
# jump to the corresponding function for each {MODE,REG} pair.
mov.w (tbl_fea_mode.b,%pc,%d0.w*2),%d0 # fetch jmp distance
jmp (tbl_fea_mode.b,%pc,%d0.w*1) # jmp to correct ea mode
swbeg &64
tbl_fea_mode:
short tbl_fea_mode - tbl_fea_mode
short tbl_fea_mode - tbl_fea_mode
short tbl_fea_mode - tbl_fea_mode
short tbl_fea_mode - tbl_fea_mode
short tbl_fea_mode - tbl_fea_mode
short tbl_fea_mode - tbl_fea_mode
short tbl_fea_mode - tbl_fea_mode
short tbl_fea_mode - tbl_fea_mode
short tbl_fea_mode - tbl_fea_mode
short tbl_fea_mode - tbl_fea_mode
short tbl_fea_mode - tbl_fea_mode
short tbl_fea_mode - tbl_fea_mode
short tbl_fea_mode - tbl_fea_mode
short tbl_fea_mode - tbl_fea_mode
short tbl_fea_mode - tbl_fea_mode
short tbl_fea_mode - tbl_fea_mode
short faddr_ind_a0 - tbl_fea_mode
short faddr_ind_a1 - tbl_fea_mode
short faddr_ind_a2 - tbl_fea_mode
short faddr_ind_a3 - tbl_fea_mode
short faddr_ind_a4 - tbl_fea_mode
short faddr_ind_a5 - tbl_fea_mode
short faddr_ind_a6 - tbl_fea_mode
short faddr_ind_a7 - tbl_fea_mode
short faddr_ind_p_a0 - tbl_fea_mode
short faddr_ind_p_a1 - tbl_fea_mode
short faddr_ind_p_a2 - tbl_fea_mode
short faddr_ind_p_a3 - tbl_fea_mode
short faddr_ind_p_a4 - tbl_fea_mode
short faddr_ind_p_a5 - tbl_fea_mode
short faddr_ind_p_a6 - tbl_fea_mode
short faddr_ind_p_a7 - tbl_fea_mode
short faddr_ind_m_a0 - tbl_fea_mode
short faddr_ind_m_a1 - tbl_fea_mode
short faddr_ind_m_a2 - tbl_fea_mode
short faddr_ind_m_a3 - tbl_fea_mode
short faddr_ind_m_a4 - tbl_fea_mode
short faddr_ind_m_a5 - tbl_fea_mode
short faddr_ind_m_a6 - tbl_fea_mode
short faddr_ind_m_a7 - tbl_fea_mode
short faddr_ind_disp_a0 - tbl_fea_mode
short faddr_ind_disp_a1 - tbl_fea_mode
short faddr_ind_disp_a2 - tbl_fea_mode
short faddr_ind_disp_a3 - tbl_fea_mode
short faddr_ind_disp_a4 - tbl_fea_mode
short faddr_ind_disp_a5 - tbl_fea_mode
short faddr_ind_disp_a6 - tbl_fea_mode
short faddr_ind_disp_a7 - tbl_fea_mode
short faddr_ind_ext - tbl_fea_mode
short faddr_ind_ext - tbl_fea_mode
short faddr_ind_ext - tbl_fea_mode
short faddr_ind_ext - tbl_fea_mode
short faddr_ind_ext - tbl_fea_mode
short faddr_ind_ext - tbl_fea_mode
short faddr_ind_ext - tbl_fea_mode
short faddr_ind_ext - tbl_fea_mode
short fabs_short - tbl_fea_mode
short fabs_long - tbl_fea_mode
short fpc_ind - tbl_fea_mode
short fpc_ind_ext - tbl_fea_mode
short tbl_fea_mode - tbl_fea_mode
short tbl_fea_mode - tbl_fea_mode
short tbl_fea_mode - tbl_fea_mode
short tbl_fea_mode - tbl_fea_mode
###################################
# Address register indirect: (An) #
###################################
faddr_ind_a0:
mov.l EXC_DREGS+0x8(%a6),%a0 # Get current a0
rts
faddr_ind_a1:
mov.l EXC_DREGS+0xc(%a6),%a0 # Get current a1
rts
faddr_ind_a2:
mov.l %a2,%a0 # Get current a2
rts
faddr_ind_a3:
mov.l %a3,%a0 # Get current a3
rts
faddr_ind_a4:
mov.l %a4,%a0 # Get current a4
rts
faddr_ind_a5:
mov.l %a5,%a0 # Get current a5
rts
faddr_ind_a6:
mov.l (%a6),%a0 # Get current a6
rts
faddr_ind_a7:
mov.l EXC_A7(%a6),%a0 # Get current a7
rts
#####################################################
# Address register indirect w/ postincrement: (An)+ #
#####################################################
faddr_ind_p_a0:
mov.l EXC_DREGS+0x8(%a6),%d0 # Get current a0
mov.l %d0,%d1
add.l %a0,%d1 # Increment
mov.l %d1,EXC_DREGS+0x8(%a6) # Save incr value
mov.l %d0,%a0
rts
faddr_ind_p_a1:
mov.l EXC_DREGS+0xc(%a6),%d0 # Get current a1
mov.l %d0,%d1
add.l %a0,%d1 # Increment
mov.l %d1,EXC_DREGS+0xc(%a6) # Save incr value
mov.l %d0,%a0
rts
faddr_ind_p_a2:
mov.l %a2,%d0 # Get current a2
mov.l %d0,%d1
add.l %a0,%d1 # Increment
mov.l %d1,%a2 # Save incr value
mov.l %d0,%a0
rts
faddr_ind_p_a3:
mov.l %a3,%d0 # Get current a3
mov.l %d0,%d1
add.l %a0,%d1 # Increment
mov.l %d1,%a3 # Save incr value
mov.l %d0,%a0
rts
faddr_ind_p_a4:
mov.l %a4,%d0 # Get current a4
mov.l %d0,%d1
add.l %a0,%d1 # Increment
mov.l %d1,%a4 # Save incr value
mov.l %d0,%a0
rts
faddr_ind_p_a5:
mov.l %a5,%d0 # Get current a5
mov.l %d0,%d1
add.l %a0,%d1 # Increment
mov.l %d1,%a5 # Save incr value
mov.l %d0,%a0
rts
faddr_ind_p_a6:
mov.l (%a6),%d0 # Get current a6
mov.l %d0,%d1
add.l %a0,%d1 # Increment
mov.l %d1,(%a6) # Save incr value
mov.l %d0,%a0
rts
faddr_ind_p_a7:
mov.b &mia7_flg,SPCOND_FLG(%a6) # set "special case" flag
mov.l EXC_A7(%a6),%d0 # Get current a7
mov.l %d0,%d1
add.l %a0,%d1 # Increment
mov.l %d1,EXC_A7(%a6) # Save incr value
mov.l %d0,%a0
rts
####################################################
# Address register indirect w/ predecrement: -(An) #
####################################################
faddr_ind_m_a0:
mov.l EXC_DREGS+0x8(%a6),%d0 # Get current a0
sub.l %a0,%d0 # Decrement
mov.l %d0,EXC_DREGS+0x8(%a6) # Save decr value
mov.l %d0,%a0
rts
faddr_ind_m_a1:
mov.l EXC_DREGS+0xc(%a6),%d0 # Get current a1
sub.l %a0,%d0 # Decrement
mov.l %d0,EXC_DREGS+0xc(%a6) # Save decr value
mov.l %d0,%a0
rts
faddr_ind_m_a2:
mov.l %a2,%d0 # Get current a2
sub.l %a0,%d0 # Decrement
mov.l %d0,%a2 # Save decr value
mov.l %d0,%a0
rts
faddr_ind_m_a3:
mov.l %a3,%d0 # Get current a3
sub.l %a0,%d0 # Decrement
mov.l %d0,%a3 # Save decr value
mov.l %d0,%a0
rts
faddr_ind_m_a4:
mov.l %a4,%d0 # Get current a4
sub.l %a0,%d0 # Decrement
mov.l %d0,%a4 # Save decr value
mov.l %d0,%a0
rts
faddr_ind_m_a5:
mov.l %a5,%d0 # Get current a5
sub.l %a0,%d0 # Decrement
mov.l %d0,%a5 # Save decr value
mov.l %d0,%a0
rts
faddr_ind_m_a6:
mov.l (%a6),%d0 # Get current a6
sub.l %a0,%d0 # Decrement
mov.l %d0,(%a6) # Save decr value
mov.l %d0,%a0
rts
faddr_ind_m_a7:
mov.b &mda7_flg,SPCOND_FLG(%a6) # set "special case" flag
mov.l EXC_A7(%a6),%d0 # Get current a7
sub.l %a0,%d0 # Decrement
mov.l %d0,EXC_A7(%a6) # Save decr value
mov.l %d0,%a0
rts
mov.l %d0,%d1
rol.w &0x4,%d1
andi.w &0xf,%d1 # extract index regno
# count on fetch_dreg() not to alter a0...
bsr.l fetch_dreg # fetch index
mov.l %d2,-(%sp) # save d2
mov.l L_SCR1(%a6),%d2 # fetch opword
btst &0xb,%d2 # is it word or long?
bne.b faii8_long
ext.l %d0 # sign extend word index
faii8_long:
mov.l %d2,%d1
rol.w &0x7,%d1
andi.l &0x3,%d1 # extract scale value
lsl.l %d1,%d0 # shift index by scale
extb.l %d2 # sign extend displacement
add.l %d2,%d0 # index + disp
add.l %d0,%a0 # An + (index + disp)
mov.l EXC_EXTWPTR(%a6),%a0 # put base in a0
subq.l &0x2,%a0 # adjust base
btst &0x8,%d0 # is disp only 8 bits?
bne.w fcalc_mem_ind # calc memory indirect
mov.l %d0,L_SCR1(%a6) # store opword
mov.l %d0,%d1 # make extword copy
rol.w &0x4,%d1 # rotate reg num into place
andi.w &0xf,%d1 # extract register number
# count on fetch_dreg() not to alter a0...
bsr.l fetch_dreg # fetch index
mov.l %d2,-(%sp) # save d2
mov.l L_SCR1(%a6),%d2 # fetch opword
btst &0xb,%d2 # is index word or long?
bne.b fpii8_long # long
ext.l %d0 # sign extend word index
fpii8_long:
mov.l %d2,%d1
rol.w &0x7,%d1 # rotate scale value into place
andi.l &0x3,%d1 # extract scale value
lsl.l %d1,%d0 # shift index by scale
extb.l %d2 # sign extend displacement
add.l %d2,%d0 # disp + index
add.l %d0,%a0 # An + (index + disp)
mov.l (%sp)+,%d2 # restore temp register
rts
# d2 = index
# d3 = base
# d4 = od
# d5 = extword
fcalc_mem_ind:
btst &0x6,%d0 # is the index suppressed?
beq.b fcalc_index
movm.l &0x3c00,-(%sp) # save d2-d5
mov.l %d0,%d5 # put extword in d5
mov.l %a0,%d3 # put base in d3
clr.l %d2 # yes, so index = 0
bra.b fbase_supp_ck
# index:
fcalc_index:
mov.l %d0,L_SCR1(%a6) # save d0 (opword)
bfextu %d0{&16:&4},%d1 # fetch dreg index
bsr.l fetch_dreg
movm.l &0x3c00,-(%sp) # save d2-d5
mov.l %d0,%d2 # put index in d2
mov.l L_SCR1(%a6),%d5
mov.l %a0,%d3
btst &0xb,%d5 # is index word or long?
bne.b fno_ext
ext.l %d2
fno_ext:
bfextu %d5{&21:&2},%d0
lsl.l %d0,%d2
# base address (passed as parameter in d3):
# we clear the value here if it should actually be suppressed.
fbase_supp_ck:
btst &0x7,%d5 # is the bd suppressed?
beq.b fno_base_sup
clr.l %d3
# base displacement:
fno_base_sup:
bfextu %d5{&26:&2},%d0 # get bd size
# beq.l fmovm_error # if (size == 0) it's reserved
mov.l %d0,USER_FPCR(%a6) # store new FPCR to mem
mov.l EXC_EXTWPTR(%a6),%a0 # fetch instruction addr
addq.l &0x4,EXC_EXTWPTR(%a6) # incr instruction ptr
bsr.l _imem_read_long # fetch FPSR from mem
tst.l %d1 # did ifetch fail?
bne.l iea_iacc # yes
mov.l %d0,USER_FPSR(%a6) # store new FPSR to mem
rts
mov.l %d0,USER_FPCR(%a6) # store new FPCR to mem
mov.l EXC_EXTWPTR(%a6),%a0 # fetch instruction addr
addq.l &0x4,EXC_EXTWPTR(%a6) # incr instruction ptr
bsr.l _imem_read_long # fetch FPSR from mem
tst.l %d1 # did ifetch fail?
bne.l iea_iacc # yes
mov.l %d0,USER_FPSR(%a6) # store new FPSR to mem
mov.l EXC_EXTWPTR(%a6),%a0 # fetch instruction addr
addq.l &0x4,EXC_EXTWPTR(%a6) # incr instruction ptr
bsr.l _imem_read_long # fetch FPIAR from mem
tst.l %d1 # did ifetch fail?
bne.l iea_iacc # yes
mov.l %d0,USER_FPIAR(%a6) # store new FPIAR to mem
rts
#########################################################################
# XDEF **************************************************************** #
# addsub_scaler2(): scale inputs to fadd/fsub such that no #
# OVFL/UNFL exceptions will result #
# #
# XREF **************************************************************** #
# norm() - normalize mantissa after adjusting exponent #
# #
# INPUT *************************************************************** #
# FP_SRC(a6) = fp op1(src) #
# FP_DST(a6) = fp op2(dst) #
# #
# OUTPUT ************************************************************** #
# FP_SRC(a6) = fp op1 scaled(src) #
# FP_DST(a6) = fp op2 scaled(dst) #
# d0 = scale amount #
# #
# ALGORITHM *********************************************************** #
# If the DST exponent is > the SRC exponent, set the DST exponent #
# equal to 0x3fff and scale the SRC exponent by the value that the #
# DST exponent was scaled by. If the SRC exponent is greater or equal, #
# do the opposite. Return this scale factor in d0. #
# If the two exponents differ by > the number of mantissa bits #
# plus two, then set the smallest exponent to a very small value as a #
# quick shortcut. #
# #
#########################################################################
quick_scale12:
andi.w &0x8000,FP_SCR0_EX(%a6) # zero src exponent
bset &0x0,1+FP_SCR0_EX(%a6) # set exp = 1
mov.l (%sp)+,%d0 # return SCALE factor
rts
# src exp is >= dst exp; scale src to exp = 0x3fff
src_exp_ge2:
bsr.l scale_to_zero_src
mov.l %d0,-(%sp) # save scale factor
cmpi.b DTAG(%a6),&DENORM # is dst denormalized?
bne.b cmpexp22
lea FP_SCR1(%a6),%a0
bsr.l norm # normalize the denorm; result is new exp
neg.w %d0 # new exp = -(shft val)
mov.w %d0,2+L_SCR1(%a6) # inset new exp
#########################################################################
# XDEF **************************************************************** #
# scale_to_zero_src(): scale the exponent of extended precision #
# value at FP_SCR0(a6). #
# #
# XREF **************************************************************** #
# norm() - normalize the mantissa if the operand was a DENORM #
# #
# INPUT *************************************************************** #
# FP_SCR0(a6) = extended precision operand to be scaled #
# #
# OUTPUT ************************************************************** #
# FP_SCR0(a6) = scaled extended precision operand #
# d0 = scale value #
# #
# ALGORITHM *********************************************************** #
# Set the exponent of the input operand to 0x3fff. Save the value #
# of the difference between the original and new exponent. Then, #
# normalize the operand if it was a DENORM. Add this normalization #
# value to the previous value. Return the result. #
# #
#########################################################################
global scale_to_zero_src
scale_to_zero_src:
mov.w FP_SCR0_EX(%a6),%d1 # extract operand's {sgn,exp}
mov.w %d1,%d0 # make a copy
stzs_denorm:
lea FP_SCR0(%a6),%a0 # pass ptr to src op
bsr.l norm # normalize denorm
neg.l %d0 # new exponent = -(shft val)
mov.l %d0,%d1 # prepare for op_norm call
bra.b stzs_norm # finish scaling
###
#########################################################################
# XDEF **************************************************************** #
# scale_sqrt(): scale the input operand exponent so a subsequent #
# fsqrt operation won't take an exception. #
# #
# XREF **************************************************************** #
# norm() - normalize the mantissa if the operand was a DENORM #
# #
# INPUT *************************************************************** #
# FP_SCR0(a6) = extended precision operand to be scaled #
# #
# OUTPUT ************************************************************** #
# FP_SCR0(a6) = scaled extended precision operand #
# d0 = scale value #
# #
# ALGORITHM *********************************************************** #
# If the input operand is a DENORM, normalize it. #
# If the exponent of the input operand is even, set the exponent #
# to 0x3ffe and return a scale factor of "(exp-0x3ffe)/2". If the #
# exponent of the input operand is off, set the exponent to ox3fff and #
# return a scale factor of "(exp-0x3fff)/2". #
# #
#########################################################################
global scale_sqrt
scale_sqrt:
cmpi.b STAG(%a6),&DENORM # is operand normalized?
beq.b ss_denorm # normalize the DENORM
#########################################################################
# XDEF **************************************************************** #
# scale_to_zero_dst(): scale the exponent of extended precision #
# value at FP_SCR1(a6). #
# #
# XREF **************************************************************** #
# norm() - normalize the mantissa if the operand was a DENORM #
# #
# INPUT *************************************************************** #
# FP_SCR1(a6) = extended precision operand to be scaled #
# #
# OUTPUT ************************************************************** #
# FP_SCR1(a6) = scaled extended precision operand #
# d0 = scale value #
# #
# ALGORITHM *********************************************************** #
# Set the exponent of the input operand to 0x3fff. Save the value #
# of the difference between the original and new exponent. Then, #
# normalize the operand if it was a DENORM. Add this normalization #
# value to the previous value. Return the result. #
# #
#########################################################################
global scale_to_zero_dst
scale_to_zero_dst:
mov.w FP_SCR1_EX(%a6),%d1 # extract operand's {sgn,exp}
mov.w %d1,%d0 # make a copy
#########################################################################
# XDEF **************************************************************** #
# res_qnan(): return default result w/ QNAN operand for dyadic #
# res_snan(): return default result w/ SNAN operand for dyadic #
# res_qnan_1op(): return dflt result w/ QNAN operand for monadic #
# res_snan_1op(): return dflt result w/ SNAN operand for monadic #
# #
# XREF **************************************************************** #
# None #
# #
# INPUT *************************************************************** #
# FP_SRC(a6) = pointer to extended precision src operand #
# FP_DST(a6) = pointer to extended precision dst operand #
# #
# OUTPUT ************************************************************** #
# fp0 = default result #
# #
# ALGORITHM *********************************************************** #
# If either operand (but not both operands) of an operation is a #
# nonsignalling NAN, then that NAN is returned as the result. If both #
# operands are nonsignalling NANs, then the destination operand #
# nonsignalling NAN is returned as the result. #
# If either operand to an operation is a signalling NAN (SNAN), #
# then, the SNAN bit is set in the FPSR EXC byte. If the SNAN trap #
# enable bit is set in the FPCR, then the trap is taken and the #
# destination is not modified. If the SNAN trap enable bit is not set, #
# then the SNAN is converted to a nonsignalling NAN (by setting the #
# SNAN bit in the operand to one), and the operation continues as #
# described in the preceding paragraph, for nonsignalling NANs. #
# Make sure the appropriate FPSR bits are set before exiting. #
# #
#########################################################################
global res_qnan
global res_snan
res_qnan:
res_snan:
cmp.b DTAG(%a6), &SNAN # is the dst an SNAN?
beq.b dst_snan2
cmp.b DTAG(%a6), &QNAN # is the dst a QNAN?
beq.b dst_qnan2
src_nan:
cmp.b STAG(%a6), &QNAN
beq.b src_qnan2
global res_snan_1op
res_snan_1op:
src_snan2:
bset &0x6, FP_SRC_HI(%a6) # set SNAN bit
or.l &nan_mask+aiop_mask+snan_mask, USER_FPSR(%a6)
lea FP_SRC(%a6), %a0
bra.b nan_comp
global res_qnan_1op
res_qnan_1op:
src_qnan2:
or.l &nan_mask, USER_FPSR(%a6)
lea FP_SRC(%a6), %a0
bra.b nan_comp
dst_snan2:
or.l &nan_mask+aiop_mask+snan_mask, USER_FPSR(%a6)
bset &0x6, FP_DST_HI(%a6) # set SNAN bit
lea FP_DST(%a6), %a0
bra.b nan_comp
dst_qnan2:
lea FP_DST(%a6), %a0
cmp.b STAG(%a6), &SNAN
bne nan_done
or.l &aiop_mask+snan_mask, USER_FPSR(%a6)
nan_done:
or.l &nan_mask, USER_FPSR(%a6)
nan_comp:
btst &0x7, FTEMP_EX(%a0) # is NAN neg?
beq.b nan_not_neg
or.l &neg_mask, USER_FPSR(%a6)
nan_not_neg:
fmovm.x (%a0), &0x80
rts
#########################################################################
# XDEF **************************************************************** #
# res_operr(): return default result during operand error #
# #
# XREF **************************************************************** #
# None #
# #
# INPUT *************************************************************** #
# None #
# #
# OUTPUT ************************************************************** #
# fp0 = default operand error result #
# #
# ALGORITHM *********************************************************** #
# An nonsignalling NAN is returned as the default result when #
# an operand error occurs for the following cases: #
# #
# Multiply: (Infinity x Zero) #
# Divide : (Zero / Zero) || (Infinity / Infinity) #
# #
#########################################################################
global res_operr
res_operr:
or.l &nan_mask+operr_mask+aiop_mask, USER_FPSR(%a6)
fmovm.x nan_return(%pc), &0x80
rts
nan_return:
long 0x7fff0000, 0xffffffff, 0xffffffff
#########################################################################
# XDEF **************************************************************** #
# _denorm(): denormalize an intermediate result #
# #
# XREF **************************************************************** #
# None #
# #
# INPUT *************************************************************** #
# a0 = points to the operand to be denormalized #
# (in the internal extended format) #
# #
# d0 = rounding precision #
# #
# OUTPUT ************************************************************** #
# a0 = pointer to the denormalized result #
# (in the internal extended format) #
# #
# d0 = guard,round,sticky #
# #
# ALGORITHM *********************************************************** #
# According to the exponent underflow threshold for the given #
# precision, shift the mantissa bits to the right in order raise the #
# exponent of the operand to the threshold value. While shifting the #
# mantissa bits right, maintain the value of the guard, round, and #
# sticky bits. #
# other notes: #
# (1) _denorm() is called by the underflow routines #
# (2) _denorm() does NOT affect the status register #
# #
#########################################################################
#
# table of exponent threshold values for each precision
#
tbl_thresh:
short 0x0
short sgl_thresh
short dbl_thresh
global _denorm
_denorm:
#
# Load the exponent threshold for the precision selected and check
# to see if (threshold - exponent) is > 65 in which case we can
# simply calculate the sticky bit and zero the mantissa. otherwise
# we have to call the denormalization routine.
#
lsr.b &0x2, %d0 # shift prec to lo bits
mov.w (tbl_thresh.b,%pc,%d0.w*2), %d1 # load prec threshold
mov.w %d1, %d0 # copy d1 into d0
sub.w FTEMP_EX(%a0), %d0 # diff = threshold - exp
cmpi.w %d0, &66 # is diff > 65? (mant + g,r bits)
bpl.b denorm_set_stky # yes; just calc sticky
clr.l %d0 # clear g,r,s
btst &inex2_bit, FPSR_EXCEPT(%a6) # yes; was INEX2 set?
beq.b denorm_call # no; don't change anything
bset &29, %d0 # yes; set sticky bit
denorm_call:
bsr.l dnrm_lp # denormalize the number
rts
#
# all bit would have been shifted off during the denorm so simply
# calculate if the sticky should be set and clear the entire mantissa.
#
denorm_set_stky:
mov.l &0x20000000, %d0 # set sticky bit in return value
mov.w %d1, FTEMP_EX(%a0) # load exp with threshold
clr.l FTEMP_HI(%a0) # set d1 = 0 (ms mantissa)
clr.l FTEMP_LO(%a0) # set d2 = 0 (ms mantissa)
rts
# #
# dnrm_lp(): normalize exponent/mantissa to specified threshhold #
# #
# INPUT: #
# %a0 : points to the operand to be denormalized #
# %d0{31:29} : initial guard,round,sticky #
# %d1{15:0} : denormalization threshold #
# OUTPUT: #
# %a0 : points to the denormalized operand #
# %d0{31:29} : final guard,round,sticky #
# #
# *** Local Equates *** #
set GRS, L_SCR2 # g,r,s temp storage
set FTEMP_LO2, L_SCR1 # FTEMP_LO copy
global dnrm_lp
dnrm_lp:
#
# make a copy of FTEMP_LO and place the g,r,s bits directly after it
# in memory so as to make the bitfield extraction for denormalization easier.
#
mov.l FTEMP_LO(%a0), FTEMP_LO2(%a6) # make FTEMP_LO copy
mov.l %d0, GRS(%a6) # place g,r,s after it
#
# check to see how much less than the underflow threshold the operand
# exponent is.
#
mov.l %d1, %d0 # copy the denorm threshold
sub.w FTEMP_EX(%a0), %d1 # d1 = threshold - uns exponent
ble.b dnrm_no_lp # d1 <= 0
cmpi.w %d1, &0x20 # is ( 0 <= d1 < 32) ?
blt.b case_1 # yes
cmpi.w %d1, &0x40 # is (32 <= d1 < 64) ?
blt.b case_2 # yes
bra.w case_3 # (d1 >= 64)
#
# No normalization necessary
#
dnrm_no_lp:
mov.l GRS(%a6), %d0 # restore original g,r,s
rts
mov.w %d0, FTEMP_EX(%a0) # exponent = denorm threshold
subi.w &0x20, %d1 # %d1 now between 0 and 32
mov.l &0x20, %d0
sub.w %d1, %d0 # %d0 = 32 - %d1
# subtle step here; or in the g,r,s at the bottom of FTEMP_LO to minimize
# the number of bits to check for the sticky detect.
# it only plays a role in shift amounts of 61-63.
mov.b GRS(%a6), %d2
or.b %d2, 3+FTEMP_LO2(%a6)
bfextu FTEMP_HI(%a0){&0:%d0}, %d2 # %d2 = new FTEMP_LO
bfextu FTEMP_HI(%a0){%d0:&32}, %d1 # %d1 = new G,R,S
bftst %d1{&2:&30} # were any bits shifted off?
bne.b case2_set_sticky # yes; set sticky bit
bftst FTEMP_LO2(%a6){%d0:&31} # were any bits shifted off?
bne.b case2_set_sticky # yes; set sticky bit
mov.l %d1, %d0 # move new G,R,S to %d0
bra.b case2_end
case2_set_sticky:
mov.l %d1, %d0 # move new G,R,S to %d0
bset &rnd_stky_bit, %d0 # set sticky bit
case2_end:
clr.l FTEMP_HI(%a0) # store FTEMP_HI = 0
mov.l %d2, FTEMP_LO(%a0) # store FTEMP_LO
and.l &0xe0000000, %d0 # clear all but G,R,S
mov.l (%sp)+,%d2 # restore temp register
rts
#
# case (d1>=64)
#
# %d0 = denorm threshold
# %d1 = amt to shift
#
case_3:
mov.w %d0, FTEMP_EX(%a0) # insert denorm threshold
#
# case (d1>65)
#
# Shift value is > 65 and out of range. All bits are shifted off.
# Return a zero mantissa with the sticky bit set
#
clr.l FTEMP_HI(%a0) # clear hi(mantissa)
clr.l FTEMP_LO(%a0) # clear lo(mantissa)
mov.l &0x20000000, %d0 # set sticky bit
rts
#
# case (d1 == 65)
#
# ---------------------------------------------------------
# | FTEMP_HI | FTEMP_LO |grs000.........000|
# ---------------------------------------------------------
# <-------(32)------>
# \ \
# \ \
# \ \
# \ ------------------------------
# -------------------------------- \
# \ \
# \ \
# \ \
# <-------(31)----->
# ---------------------------------------------------------
# |0...............0|0................0|0rs |
# ---------------------------------------------------------
#
case3_65:
mov.l FTEMP_HI(%a0), %d0 # fetch hi(mantissa)
and.l &0x80000000, %d0 # extract R bit
lsr.l &0x1, %d0 # shift high bit into R bit
and.l &0x7fffffff, %d1 # extract other bits
case3_complete:
# last operation done was an "and" of the bits shifted off so the condition
# codes are already set so branch accordingly.
bne.b case3_set_sticky # yes; go set new sticky
tst.l FTEMP_LO(%a0) # were any bits shifted off?
bne.b case3_set_sticky # yes; go set new sticky
tst.b GRS(%a6) # were any bits shifted off?
bne.b case3_set_sticky # yes; go set new sticky
#
# no bits were shifted off so don't set the sticky bit.
# the guard and
# the entire mantissa is zero.
#
clr.l FTEMP_HI(%a0) # clear hi(mantissa)
clr.l FTEMP_LO(%a0) # clear lo(mantissa)
rts
#
# some bits were shifted off so set the sticky bit.
# the entire mantissa is zero.
#
case3_set_sticky:
bset &rnd_stky_bit,%d0 # set new sticky bit
clr.l FTEMP_HI(%a0) # clear hi(mantissa)
clr.l FTEMP_LO(%a0) # clear lo(mantissa)
rts
#########################################################################
# XDEF **************************************************************** #
# _round(): round result according to precision/mode #
# #
# XREF **************************************************************** #
# None #
# #
# INPUT *************************************************************** #
# a0 = ptr to input operand in internal extended format #
# d1(hi) = contains rounding precision: #
# ext = $0000xxxx #
# sgl = $0004xxxx #
# dbl = $0008xxxx #
# d1(lo) = contains rounding mode: #
# RN = $xxxx0000 #
# RZ = $xxxx0001 #
# RM = $xxxx0002 #
# RP = $xxxx0003 #
# d0{31:29} = contains the g,r,s bits (extended) #
# #
# OUTPUT ************************************************************** #
# a0 = pointer to rounded result #
# #
# ALGORITHM *********************************************************** #
# On return the value pointed to by a0 is correctly rounded, #
# a0 is preserved and the g-r-s bits in d0 are cleared. #
# The result is not typed - the tag field is invalid. The #
# result is still in the internal extended format. #
# #
# The INEX bit of USER_FPSR will be set if the rounded result was #
# inexact (i.e. if any of the g-r-s bits were set). #
# #
#########################################################################
global _round
_round:
#
# ext_grs() looks at the rounding precision and sets the appropriate
# G,R,S bits.
# If (G,R,S == 0) then result is exact and round is done, else set
# the inex flag in status reg and continue.
#
bsr.l ext_grs # extract G,R,S
tst.l %d0 # are G,R,S zero?
beq.w truncate # yes; round is complete
or.w &inx2a_mask, 2+USER_FPSR(%a6) # set inex2/ainex
#
# Use rounding mode as an index into a jump table for these modes.
# All of the following assumes grs != 0.
#
mov.w (tbl_mode.b,%pc,%d1.w*2), %a1 # load jump offset
jmp (tbl_mode.b,%pc,%a1) # jmp to rnd mode handler
tbl_mode:
short rnd_near - tbl_mode
short truncate - tbl_mode # RZ always truncates
short rnd_mnus - tbl_mode
short rnd_plus - tbl_mode
#################################################################
# ROUND PLUS INFINITY #
# #
# If sign of fp number = 0 (positive), then add 1 to l. #
#################################################################
rnd_plus:
tst.b FTEMP_SGN(%a0) # check for sign
bmi.w truncate # if positive then truncate
mov.l &0xffffffff, %d0 # force g,r,s to be all f's
swap %d1 # set up d1 for round prec.
#################################################################
# ROUND MINUS INFINITY #
# #
# If sign of fp number = 1 (negative), then add 1 to l. #
#################################################################
rnd_mnus:
tst.b FTEMP_SGN(%a0) # check for sign
bpl.w truncate # if negative then truncate
mov.l &0xffffffff, %d0 # force g,r,s to be all f's
swap %d1 # set up d1 for round prec.
#################################################################
# ROUND NEAREST #
# #
# If (g=1), then add 1 to l and if (r=s=0), then clear l #
# Note that this will round to even in case of a tie. #
#################################################################
rnd_near:
asl.l &0x1, %d0 # shift g-bit to c-bit
bcc.w truncate # if (g=1) then
# *** LOCAL EQUATES ***
set ad_1_sgl, 0x00000100 # constant to add 1 to l-bit in sgl prec
set ad_1_dbl, 0x00000800 # constant to add 1 to l-bit in dbl prec
#########################
# ADD SINGLE #
#########################
add_sgl:
add.l &ad_1_sgl, FTEMP_HI(%a0)
bcc.b scc_clr # no mantissa overflow
roxr.w FTEMP_HI(%a0) # shift v-bit back in
roxr.w FTEMP_HI+2(%a0) # shift v-bit back in
add.w &0x1, FTEMP_EX(%a0) # and incr exponent
scc_clr:
tst.l %d0 # test for rs = 0
bne.b sgl_done
and.w &0xfe00, FTEMP_HI+2(%a0) # clear the l-bit
sgl_done:
and.l &0xffffff00, FTEMP_HI(%a0) # truncate bits beyond sgl limit
clr.l FTEMP_LO(%a0) # clear d2
rts
#########################
# ADD EXTENDED #
#########################
add_ext:
addq.l &1,FTEMP_LO(%a0) # add 1 to l-bit
bcc.b xcc_clr # test for carry out
addq.l &1,FTEMP_HI(%a0) # propogate carry
bcc.b xcc_clr
roxr.w FTEMP_HI(%a0) # mant is 0 so restore v-bit
roxr.w FTEMP_HI+2(%a0) # mant is 0 so restore v-bit
roxr.w FTEMP_LO(%a0)
roxr.w FTEMP_LO+2(%a0)
add.w &0x1,FTEMP_EX(%a0) # and inc exp
xcc_clr:
tst.l %d0 # test rs = 0
bne.b add_ext_done
and.b &0xfe,FTEMP_LO+3(%a0) # clear the l bit
add_ext_done:
rts
#
# ext_grs(): extract guard, round and sticky bits according to
# rounding precision.
#
# INPUT
# d0 = extended precision g,r,s (in d0{31:29})
# d1 = {PREC,ROUND}
# OUTPUT
# d0{31:29} = guard, round, sticky
#
# The ext_grs extract the guard/round/sticky bits according to the
# selected rounding precision. It is called by the round subroutine
# only. All registers except d0 are kept intact. d0 becomes an
# updated guard,round,sticky in d0{31:29}
#
# Notes: the ext_grs uses the round PREC, and therefore has to swap d1
# prior to usage, and needs to restore d1 to original. this
# routine is tightly tied to the round routine and not meant to
# uphold standard subroutine calling practices.
#
ext_grs:
swap %d1 # have d1.w point to round precision
tst.b %d1 # is rnd prec = extended?
bne.b ext_grs_not_ext # no; go handle sgl or dbl
#
# %d0 actually already hold g,r,s since _round() had it before calling
# this function. so, as long as we don't disturb it, we are "returning" it.
#
ext_grs_ext:
swap %d1 # yes; return to correct positions
rts
ext_grs_not_ext:
movm.l &0x3000, -(%sp) # make some temp registers {d2/d3}
cmpi.b %d1, &s_mode # is rnd prec = sgl?
bne.b ext_grs_dbl # no; go handle dbl
#
# sgl:
# 96 64 40 32 0
# -----------------------------------------------------
# | EXP |XXXXXXX| |xx | |grs|
# -----------------------------------------------------
# <--(24)--->nn\ /
# ee ---------------------
# ww |
# v
# gr new sticky
#
ext_grs_sgl:
bfextu FTEMP_HI(%a0){&24:&2}, %d3 # sgl prec. g-r are 2 bits right
mov.l &30, %d2 # of the sgl prec. limits
lsl.l %d2, %d3 # shift g-r bits to MSB of d3
mov.l FTEMP_HI(%a0), %d2 # get word 2 for s-bit test
and.l &0x0000003f, %d2 # s bit is the or of all other
bne.b ext_grs_st_stky # bits to the right of g-r
tst.l FTEMP_LO(%a0) # test lower mantissa
bne.b ext_grs_st_stky # if any are set, set sticky
tst.l %d0 # test original g,r,s
bne.b ext_grs_st_stky # if any are set, set sticky
bra.b ext_grs_end_sd # if words 3 and 4 are clr, exit
#
# dbl:
# 96 64 32 11 0
# -----------------------------------------------------
# | EXP |XXXXXXX| | |xx |grs|
# -----------------------------------------------------
# nn\ /
# ee -------
# ww |
# v
# gr new sticky
#
ext_grs_dbl:
bfextu FTEMP_LO(%a0){&21:&2}, %d3 # dbl-prec. g-r are 2 bits right
mov.l &30, %d2 # of the dbl prec. limits
lsl.l %d2, %d3 # shift g-r bits to the MSB of d3
mov.l FTEMP_LO(%a0), %d2 # get lower mantissa for s-bit test
and.l &0x000001ff, %d2 # s bit is the or-ing of all
bne.b ext_grs_st_stky # other bits to the right of g-r
tst.l %d0 # test word original g,r,s
bne.b ext_grs_st_stky # if any are set, set sticky
bra.b ext_grs_end_sd # if clear, exit
ext_grs_st_stky:
bset &rnd_stky_bit, %d3 # set sticky bit
ext_grs_end_sd:
mov.l %d3, %d0 # return grs to d0
#########################################################################
# unnorm_fix(): - changes an UNNORM to one of NORM, DENORM, or ZERO #
# - returns corresponding optype tag #
# #
# XDEF **************************************************************** #
# unnorm_fix() #
# #
# XREF **************************************************************** #
# norm() - normalize the mantissa #
# #
# INPUT *************************************************************** #
# a0 = pointer to unnormalized extended precision number #
# #
# OUTPUT ************************************************************** #
# d0 = optype tag - is corrected to one of NORM, DENORM, or ZERO #
# a0 = input operand has been converted to a norm, denorm, or #
# zero; both the exponent and mantissa are changed. #
# #
#########################################################################
global unnorm_fix
unnorm_fix:
bfffo FTEMP_HI(%a0){&0:&32}, %d0 # how many shifts are needed?
bne.b unnorm_shift # hi(man) is not all zeroes
#
# hi(man) is all zeroes so see if any bits in lo(man) are set
#
unnorm_chk_lo:
bfffo FTEMP_LO(%a0){&0:&32}, %d0 # is operand really a zero?
beq.w unnorm_zero # yes
add.w &32, %d0 # no; fix shift distance
#
# d0 = # shifts needed for complete normalization
#
unnorm_shift:
clr.l %d1 # clear top word
mov.w FTEMP_EX(%a0), %d1 # extract exponent
and.w &0x7fff, %d1 # strip off sgn
cmp.w %d0, %d1 # will denorm push exp < 0?
bgt.b unnorm_nrm_zero # yes; denorm only until exp = 0
#
# exponent would not go < 0. therefore, number stays normalized
#
sub.w %d0, %d1 # shift exponent value
mov.w FTEMP_EX(%a0), %d0 # load old exponent
and.w &0x8000, %d0 # save old sign
or.w %d0, %d1 # {sgn,new exp}
mov.w %d1, FTEMP_EX(%a0) # insert new exponent
bsr.l norm # normalize UNNORM
mov.b &NORM, %d0 # return new optype tag
rts
#
# exponent would go < 0, so only denormalize until exp = 0
#
unnorm_nrm_zero:
cmp.b %d1, &32 # is exp <= 32?
bgt.b unnorm_nrm_zero_lrg # no; go handle large exponent
bfextu FTEMP_HI(%a0){%d1:&32}, %d0 # extract new hi(man)
mov.l %d0, FTEMP_HI(%a0) # save new hi(man)
mov.l FTEMP_LO(%a0), %d0 # fetch old lo(man)
lsl.l %d1, %d0 # extract new lo(man)
mov.l %d0, FTEMP_LO(%a0) # save new lo(man)
and.w &0x8000, FTEMP_EX(%a0) # set exp = 0
mov.b &DENORM, %d0 # return new optype tag
rts
#
# only mantissa bits set are in lo(man)
#
unnorm_nrm_zero_lrg:
sub.w &32, %d1 # adjust shft amt by 32
mov.l FTEMP_LO(%a0), %d0 # fetch old lo(man)
lsl.l %d1, %d0 # left shift lo(man)
mov.l %d0, FTEMP_HI(%a0) # store new hi(man)
clr.l FTEMP_LO(%a0) # lo(man) = 0
and.w &0x8000, FTEMP_EX(%a0) # set exp = 0
mov.b &DENORM, %d0 # return new optype tag
rts
#
# whole mantissa is zero so this UNNORM is actually a zero
#
unnorm_zero:
and.w &0x8000, FTEMP_EX(%a0) # force exponent to zero
mov.b &ZERO, %d0 # fix optype tag
rts
#########################################################################
# XDEF **************************************************************** #
# set_tag_x(): return the optype of the input ext fp number #
# #
# XREF **************************************************************** #
# None #
# #
# INPUT *************************************************************** #
# a0 = pointer to extended precision operand #
# #
# OUTPUT ************************************************************** #
# d0 = value of type tag #
# one of: NORM, INF, QNAN, SNAN, DENORM, UNNORM, ZERO #
# #
# ALGORITHM *********************************************************** #
# Simply test the exponent, j-bit, and mantissa values to #
# determine the type of operand. #
# If it's an unnormalized zero, alter the operand and force it #
# to be a normal zero. #
# #
#########################################################################
global set_tag_x
set_tag_x:
mov.w FTEMP_EX(%a0), %d0 # extract exponent
andi.w &0x7fff, %d0 # strip off sign
cmpi.w %d0, &0x7fff # is (EXP == MAX)?
beq.b inf_or_nan_x
not_inf_or_nan_x:
btst &0x7,FTEMP_HI(%a0)
beq.b not_norm_x
is_norm_x:
mov.b &NORM, %d0
rts
not_norm_x:
tst.w %d0 # is exponent = 0?
bne.b is_unnorm_x
not_unnorm_x:
tst.l FTEMP_HI(%a0)
bne.b is_denorm_x
tst.l FTEMP_LO(%a0)
bne.b is_denorm_x
is_zero_x:
mov.b &ZERO, %d0
rts
is_denorm_x:
mov.b &DENORM, %d0
rts
# must distinguish now "Unnormalized zeroes" which we
# must convert to zero.
is_unnorm_x:
tst.l FTEMP_HI(%a0)
bne.b is_unnorm_reg_x
tst.l FTEMP_LO(%a0)
bne.b is_unnorm_reg_x
# it's an "unnormalized zero". let's convert it to an actual zero...
andi.w &0x8000,FTEMP_EX(%a0) # clear exponent
mov.b &ZERO, %d0
rts
is_unnorm_reg_x:
mov.b &UNNORM, %d0
rts
inf_or_nan_x:
tst.l FTEMP_LO(%a0)
bne.b is_nan_x
mov.l FTEMP_HI(%a0), %d0
and.l &0x7fffffff, %d0 # msb is a don't care!
bne.b is_nan_x
is_inf_x:
mov.b &INF, %d0
rts
is_nan_x:
btst &0x6, FTEMP_HI(%a0)
beq.b is_snan_x
mov.b &QNAN, %d0
rts
is_snan_x:
mov.b &SNAN, %d0
rts
#########################################################################
# XDEF **************************************************************** #
# set_tag_d(): return the optype of the input dbl fp number #
# #
# XREF **************************************************************** #
# None #
# #
# INPUT *************************************************************** #
# a0 = points to double precision operand #
# #
# OUTPUT ************************************************************** #
# d0 = value of type tag #
# one of: NORM, INF, QNAN, SNAN, DENORM, ZERO #
# #
# ALGORITHM *********************************************************** #
# Simply test the exponent, j-bit, and mantissa values to #
# determine the type of operand. #
# #
#########################################################################
global set_tag_d
set_tag_d:
mov.l FTEMP(%a0), %d0
mov.l %d0, %d1
#########################################################################
# XDEF **************************************************************** #
# set_tag_s(): return the optype of the input sgl fp number #
# #
# XREF **************************************************************** #
# None #
# #
# INPUT *************************************************************** #
# a0 = pointer to single precision operand #
# #
# OUTPUT ************************************************************** #
# d0 = value of type tag #
# one of: NORM, INF, QNAN, SNAN, DENORM, ZERO #
# #
# ALGORITHM *********************************************************** #
# Simply test the exponent, j-bit, and mantissa values to #
# determine the type of operand. #
# #
#########################################################################
global set_tag_s
set_tag_s:
mov.l FTEMP(%a0), %d0
mov.l %d0, %d1
#########################################################################
# XDEF **************************************************************** #
# unf_res(): routine to produce default underflow result of a #
# scaled extended precision number; this is used by #
# fadd/fdiv/fmul/etc. emulation routines. #
# unf_res4(): same as above but for fsglmul/fsgldiv which use #
# single round prec and extended prec mode. #
# #
# XREF **************************************************************** #
# _denorm() - denormalize according to scale factor #
# _round() - round denormalized number according to rnd prec #
# #
# INPUT *************************************************************** #
# a0 = pointer to extended precison operand #
# d0 = scale factor #
# d1 = rounding precision/mode #
# #
# OUTPUT ************************************************************** #
# a0 = pointer to default underflow result in extended precision #
# d0.b = result FPSR_cc which caller may or may not want to save #
# #
# ALGORITHM *********************************************************** #
# Convert the input operand to "internal format" which means the #
# exponent is extended to 16 bits and the sign is stored in the unused #
# portion of the extended precison operand. Denormalize the number #
# according to the scale factor passed in d0. Then, round the #
# denormalized result. #
# Set the FPSR_exc bits as appropriate but return the cc bits in #
# d0 in case the caller doesn't want to save them (as is the case for #
# fmove out). #
# unf_res4() for fsglmul/fsgldiv forces the denorm to extended #
# precision and the rounding mode to single. #
# #
#########################################################################
global unf_res
unf_res:
mov.l %d1, -(%sp) # save rnd prec,mode on stack
btst &0x7, FTEMP_EX(%a0) # make "internal" format
sne FTEMP_SGN(%a0)
# result is now rounded properly. convert back to normal format
bclr &0x7, FTEMP_EX(%a0) # clear sgn first; may have residue
tst.b FTEMP_SGN(%a0) # is "internal result" sign set?
beq.b unf_res_chkifzero # no; result is positive
bset &0x7, FTEMP_EX(%a0) # set result sgn
clr.b FTEMP_SGN(%a0) # clear temp sign
# the number may have become zero after rounding. set ccodes accordingly.
unf_res_chkifzero:
clr.l %d0
tst.l FTEMP_HI(%a0) # is value now a zero?
bne.b unf_res_cont # no
tst.l FTEMP_LO(%a0)
bne.b unf_res_cont # no
# bset &z_bit, FPSR_CC(%a6) # yes; set zero ccode bit
bset &z_bit, %d0 # yes; set zero ccode bit
unf_res_cont:
#
# can inex1 also be set along with unfl and inex2???
#
# we know that underflow has occurred. aunfl should be set if INEX2 is also set.
#
btst &inex2_bit, FPSR_EXCEPT(%a6) # is INEX2 set?
beq.b unf_res_end # no
bset &aunfl_bit, FPSR_AEXCEPT(%a6) # yes; set aunfl
unf_res_end:
add.l &0x4, %sp # clear stack
rts
# unf_res() for fsglmul() and fsgldiv().
global unf_res4
unf_res4:
mov.l %d1,-(%sp) # save rnd prec,mode on stack
btst &0x7,FTEMP_EX(%a0) # make "internal" format
sne FTEMP_SGN(%a0)
# result is now rounded properly. convert back to normal format
bclr &0x7,FTEMP_EX(%a0) # clear sgn first; may have residue
tst.b FTEMP_SGN(%a0) # is "internal result" sign set?
beq.b unf_res4_chkifzero # no; result is positive
bset &0x7,FTEMP_EX(%a0) # set result sgn
clr.b FTEMP_SGN(%a0) # clear temp sign
# the number may have become zero after rounding. set ccodes accordingly.
unf_res4_chkifzero:
clr.l %d0
tst.l FTEMP_HI(%a0) # is value now a zero?
bne.b unf_res4_cont # no
tst.l FTEMP_LO(%a0)
bne.b unf_res4_cont # no
# bset &z_bit,FPSR_CC(%a6) # yes; set zero ccode bit
bset &z_bit,%d0 # yes; set zero ccode bit
unf_res4_cont:
#
# can inex1 also be set along with unfl and inex2???
#
# we know that underflow has occurred. aunfl should be set if INEX2 is also set.
#
btst &inex2_bit,FPSR_EXCEPT(%a6) # is INEX2 set?
beq.b unf_res4_end # no
bset &aunfl_bit,FPSR_AEXCEPT(%a6) # yes; set aunfl
unf_res4_end:
add.l &0x4,%sp # clear stack
rts
#########################################################################
# XDEF **************************************************************** #
# ovf_res(): routine to produce the default overflow result of #
# an overflowing number. #
# ovf_res2(): same as above but the rnd mode/prec are passed #
# differently. #
# #
# XREF **************************************************************** #
# none #
# #
# INPUT *************************************************************** #
# d1.b = '-1' => (-); '0' => (+) #
# ovf_res(): #
# d0 = rnd mode/prec #
# ovf_res2(): #
# hi(d0) = rnd prec #
# lo(d0) = rnd mode #
# #
# OUTPUT ************************************************************** #
# a0 = points to extended precision result #
# d0.b = condition code bits #
# #
# ALGORITHM *********************************************************** #
# The default overflow result can be determined by the sign of #
# the result and the rounding mode/prec in effect. These bits are #
# concatenated together to create an index into the default result #
# table. A pointer to the correct result is returned in a0. The #
# resulting condition codes are returned in d0 in case the caller #
# doesn't want FPSR_cc altered (as is the case for fmove out). #
# #
#########################################################################
global ovf_res
ovf_res:
andi.w &0x10,%d1 # keep result sign
lsr.b &0x4,%d0 # shift prec/mode
or.b %d0,%d1 # concat the two
mov.w %d1,%d0 # make a copy
lsl.b &0x1,%d1 # multiply d1 by 2
bra.b ovf_res_load
global ovf_res2
ovf_res2:
and.w &0x10, %d1 # keep result sign
or.b %d0, %d1 # insert rnd mode
swap %d0
or.b %d0, %d1 # insert rnd prec
mov.w %d1, %d0 # make a copy
lsl.b &0x1, %d1 # shift left by 1
#
# use the rounding mode, precision, and result sign as in index into the
# two tables below to fetch the default result and the result ccodes.
#
ovf_res_load:
mov.b (tbl_ovfl_cc.b,%pc,%d0.w*1), %d0 # fetch result ccodes
lea (tbl_ovfl_result.b,%pc,%d1.w*8), %a0 # return result ptr
tbl_ovfl_result:
long 0x7fff0000,0x00000000,0x00000000,0x00000000 # +INF; RN
long 0x7ffe0000,0xffffffff,0xffffffff,0x00000000 # +EXT; RZ
long 0x7ffe0000,0xffffffff,0xffffffff,0x00000000 # +EXT; RM
long 0x7fff0000,0x00000000,0x00000000,0x00000000 # +INF; RP
long 0x7fff0000,0x00000000,0x00000000,0x00000000 # +INF; RN
long 0x407e0000,0xffffff00,0x00000000,0x00000000 # +SGL; RZ
long 0x407e0000,0xffffff00,0x00000000,0x00000000 # +SGL; RM
long 0x7fff0000,0x00000000,0x00000000,0x00000000 # +INF; RP
long 0x7fff0000,0x00000000,0x00000000,0x00000000 # +INF; RN
long 0x43fe0000,0xffffffff,0xfffff800,0x00000000 # +DBL; RZ
long 0x43fe0000,0xffffffff,0xfffff800,0x00000000 # +DBL; RM
long 0x7fff0000,0x00000000,0x00000000,0x00000000 # +INF; RP
long 0x00000000,0x00000000,0x00000000,0x00000000
long 0x00000000,0x00000000,0x00000000,0x00000000
long 0x00000000,0x00000000,0x00000000,0x00000000
long 0x00000000,0x00000000,0x00000000,0x00000000
long 0xffff0000,0x00000000,0x00000000,0x00000000 # -INF; RN
long 0xfffe0000,0xffffffff,0xffffffff,0x00000000 # -EXT; RZ
long 0xffff0000,0x00000000,0x00000000,0x00000000 # -INF; RM
long 0xfffe0000,0xffffffff,0xffffffff,0x00000000 # -EXT; RP
long 0xffff0000,0x00000000,0x00000000,0x00000000 # -INF; RN
long 0xc07e0000,0xffffff00,0x00000000,0x00000000 # -SGL; RZ
long 0xffff0000,0x00000000,0x00000000,0x00000000 # -INF; RM
long 0xc07e0000,0xffffff00,0x00000000,0x00000000 # -SGL; RP
long 0xffff0000,0x00000000,0x00000000,0x00000000 # -INF; RN
long 0xc3fe0000,0xffffffff,0xfffff800,0x00000000 # -DBL; RZ
long 0xffff0000,0x00000000,0x00000000,0x00000000 # -INF; RM
long 0xc3fe0000,0xffffffff,0xfffff800,0x00000000 # -DBL; RP
#########################################################################
# XDEF **************************************************************** #
# fout(): move from fp register to memory or data register #
# #
# XREF **************************************************************** #
# _round() - needed to create EXOP for sgl/dbl precision #
# norm() - needed to create EXOP for extended precision #
# ovf_res() - create default overflow result for sgl/dbl precision#
# unf_res() - create default underflow result for sgl/dbl prec. #
# dst_dbl() - create rounded dbl precision result. #
# dst_sgl() - create rounded sgl precision result. #
# fetch_dreg() - fetch dynamic k-factor reg for packed. #
# bindec() - convert FP binary number to packed number. #
# _mem_write() - write data to memory. #
# _mem_write2() - write data to memory unless supv mode -(a7) exc.#
# _dmem_write_{byte,word,long}() - write data to memory. #
# store_dreg_{b,w,l}() - store data to data register file. #
# facc_out_{b,w,l,d,x}() - data access error occurred. #
# #
# INPUT *************************************************************** #
# a0 = pointer to extended precision source operand #
# d0 = round prec,mode #
# #
# OUTPUT ************************************************************** #
# fp0 : intermediate underflow or overflow result if #
# OVFL/UNFL occurred for a sgl or dbl operand #
# #
# ALGORITHM *********************************************************** #
# This routine is accessed by many handlers that need to do an #
# opclass three move of an operand out to memory. #
# Decode an fmove out (opclass 3) instruction to determine if #
# it's b,w,l,s,d,x, or p in size. b,w,l can be stored to either a data #
# register or memory. The algorithm uses a standard "fmove" to create #
# the rounded result. Also, since exceptions are disabled, this also #
# create the correct OPERR default result if appropriate. #
# For sgl or dbl precision, overflow or underflow can occur. If #
# either occurs and is enabled, the EXOP. #
# For extended precision, the stacked <ea> must be fixed along #
# w/ the address index register as appropriate w/ _calc_ea_fout(). If #
# the source is a denorm and if underflow is enabled, an EXOP must be #
# created. #
# For packed, the k-factor must be fetched from the instruction #
# word or a data register. The <ea> must be fixed as w/ extended #
# precision. Then, bindec() is called to create the appropriate #
# packed result. #
# If at any time an access error is flagged by one of the move- #
# to-memory routines, then a special exit must be made so that the #
# access error can be handled properly. #
# #
#########################################################################
global fout
fout:
bfextu EXC_CMDREG(%a6){&3:&3},%d1 # extract dst fmt
mov.w (tbl_fout.b,%pc,%d1.w*2),%a1 # use as index
jmp (tbl_fout.b,%pc,%a1) # jump to routine
swbeg &0x8
tbl_fout:
short fout_long - tbl_fout
short fout_sgl - tbl_fout
short fout_ext - tbl_fout
short fout_pack - tbl_fout
short fout_word - tbl_fout
short fout_dbl - tbl_fout
short fout_byte - tbl_fout
short fout_pack - tbl_fout
#################################################################
# fmove.b out ###################################################
#################################################################
# Only "Unimplemented Data Type" exceptions enter here. The operand
# is either a DENORM or a NORM.
fout_byte:
tst.b STAG(%a6) # is operand normalized?
bne.b fout_byte_denorm # no
#################################################################
# fmove.w out ###################################################
#################################################################
# Only "Unimplemented Data Type" exceptions enter here. The operand
# is either a DENORM or a NORM.
fout_word:
tst.b STAG(%a6) # is operand normalized?
bne.b fout_word_denorm # no
#################################################################
# fmove.l out ###################################################
#################################################################
# Only "Unimplemented Data Type" exceptions enter here. The operand
# is either a DENORM or a NORM.
fout_long:
tst.b STAG(%a6) # is operand normalized?
bne.b fout_long_denorm # no
#################################################################
# fmove.x out ###################################################
#################################################################
# Only "Unimplemented Data Type" exceptions enter here. The operand
# is either a DENORM or a NORM.
# The DENORM causes an Underflow exception.
fout_ext:
# we copy the extended precision result to FP_SCR0 so that the reserved
# 16-bit field gets zeroed. we do this since we promise not to disturb
# what's at SRC(a0).
mov.w SRC_EX(%a0),FP_SCR0_EX(%a6)
clr.w 2+FP_SCR0_EX(%a6) # clear reserved field
mov.l SRC_HI(%a0),FP_SCR0_HI(%a6)
mov.l SRC_LO(%a0),FP_SCR0_LO(%a6)
# we must not yet write the extended precision data to the stack
# in the pre-decrement case from supervisor mode or else we'll corrupt
# the stack frame. so, leave it in FP_SRC for now and deal with it later...
cmpi.b SPCOND_FLG(%a6),&mda7_flg
beq.b fout_ext_a7
bsr.l _dmem_write # write ext prec number to memory
tst.l %d1 # did dstore fail?
bne.w fout_ext_err # yes
tst.b STAG(%a6) # is operand normalized?
bne.b fout_ext_denorm # no
rts
# the number is a DENORM. must set the underflow exception bit
fout_ext_denorm:
bset &unfl_bit,FPSR_EXCEPT(%a6) # set underflow exc bit
mov.b FPCR_ENABLE(%a6),%d0
andi.b &0x0a,%d0 # is UNFL or INEX enabled?
bne.b fout_ext_exc # yes
rts
# we don't want to do the write if the exception occurred in supervisor mode
# so _mem_write2() handles this for us.
fout_ext_a7:
bsr.l _mem_write2 # write ext prec number to memory
tst.l %d1 # did dstore fail?
bne.w fout_ext_err # yes
tst.b STAG(%a6) # is operand normalized?
bne.b fout_ext_denorm # no
rts
fout_ext_exc:
lea FP_SCR0(%a6),%a0
bsr.l norm # normalize the mantissa
neg.w %d0 # new exp = -(shft amt)
andi.w &0x7fff,%d0
andi.w &0x8000,FP_SCR0_EX(%a6) # keep only old sign
or.w %d0,FP_SCR0_EX(%a6) # insert new exponent
fmovm.x FP_SCR0(%a6),&0x40 # return EXOP in fp1
rts
#########################################################################
# fmove.s out ###########################################################
#########################################################################
fout_sgl:
andi.b &0x30,%d0 # clear rnd prec
ori.b &s_mode*0x10,%d0 # insert sgl prec
mov.l %d0,L_SCR3(%a6) # save rnd prec,mode on stack
#
# operand is a normalized number. first, we check to see if the move out
# would cause either an underflow or overflow. these cases are handled
# separately. otherwise, set the FPCR to the proper rounding mode and
# execute the move.
#
mov.w SRC_EX(%a0),%d0 # extract exponent
andi.w &0x7fff,%d0 # strip sign
cmpi.w %d0,&SGL_HI # will operand overflow?
bgt.w fout_sgl_ovfl # yes; go handle OVFL
beq.w fout_sgl_may_ovfl # maybe; go handle possible OVFL
cmpi.w %d0,&SGL_LO # will operand underflow?
blt.w fout_sgl_unfl # yes; go handle underflow
#
# NORMs(in range) can be stored out by a simple "fmov.s"
# Unnormalized inputs can come through this point.
#
fout_sgl_exg:
fmovm.x SRC(%a0),&0x80 # fetch fop from stack
fmov.l L_SCR3(%a6),%fpcr # set FPCR
fmov.l &0x0,%fpsr # clear FPSR
fmov.s %fp0,%d0 # store does convert and round
fmov.l &0x0,%fpcr # clear FPCR
fmov.l %fpsr,%d1 # save FPSR
or.w %d1,2+USER_FPSR(%a6) # set possible inex2/ainex
fout_sgl_exg_write:
mov.b 1+EXC_OPWORD(%a6),%d1 # extract dst mode
andi.b &0x38,%d1 # is mode == 0? (Dreg dst)
beq.b fout_sgl_exg_write_dn # must save to integer regfile
mov.l EXC_EA(%a6),%a0 # stacked <ea> is correct
bsr.l _dmem_write_long # write long
tst.l %d1 # did dstore fail?
bne.l facc_out_l # yes
#
# here, we know that the operand would UNFL if moved out to single prec,
# so, denorm and round and then use generic store single routine to
# write the value to memory.
#
fout_sgl_unfl:
bset &unfl_bit,FPSR_EXCEPT(%a6) # set UNFL
fout_sgl_unfl_chkexc:
mov.b FPCR_ENABLE(%a6),%d1
andi.b &0x0a,%d1 # is UNFL or INEX enabled?
bne.w fout_sd_exc_unfl # yes
addq.l &0x4,%sp
rts
#
# it's definitely an overflow so call ovf_res to get the correct answer
#
fout_sgl_ovfl:
tst.b 3+SRC_HI(%a0) # is result inexact?
bne.b fout_sgl_ovfl_inex2
tst.l SRC_LO(%a0) # is result inexact?
bne.b fout_sgl_ovfl_inex2
ori.w &ovfl_inx_mask,2+USER_FPSR(%a6) # set ovfl/aovfl/ainex
bra.b fout_sgl_ovfl_cont
fout_sgl_ovfl_inex2:
ori.w &ovfinx_mask,2+USER_FPSR(%a6) # set ovfl/aovfl/ainex/inex2
fout_sgl_ovfl_cont:
mov.l %a0,-(%sp)
# call ovf_res() w/ sgl prec and the correct rnd mode to create the default
# overflow result. DON'T save the returned ccodes from ovf_res() since
# fmove out doesn't alter them.
tst.b SRC_EX(%a0) # is operand negative?
smi %d1 # set if so
mov.l L_SCR3(%a6),%d0 # pass: sgl prec,rnd mode
bsr.l ovf_res # calc OVFL result
fmovm.x (%a0),&0x80 # load default overflow result
fmov.s %fp0,%d0 # store to single
mov.b 1+EXC_OPWORD(%a6),%d1 # extract dst mode
andi.b &0x38,%d1 # is mode == 0? (Dreg dst)
beq.b fout_sgl_ovfl_dn # must save to integer regfile
mov.l EXC_EA(%a6),%a0 # stacked <ea> is correct
bsr.l _dmem_write_long # write long
tst.l %d1 # did dstore fail?
bne.l facc_out_l # yes
fout_sgl_ovfl_chkexc:
mov.b FPCR_ENABLE(%a6),%d1
andi.b &0x0a,%d1 # is UNFL or INEX enabled?
bne.w fout_sd_exc_ovfl # yes
addq.l &0x4,%sp
rts
#
# move out MAY overflow:
# (1) force the exp to 0x3fff
# (2) do a move w/ appropriate rnd mode
# (3) if exp still equals zero, then insert original exponent
# for the correct result.
# if exp now equals one, then it overflowed so call ovf_res.
#
fout_sgl_may_ovfl:
mov.w SRC_EX(%a0),%d1 # fetch current sign
andi.w &0x8000,%d1 # keep it,clear exp
ori.w &0x3fff,%d1 # insert exp = 0
mov.w %d1,FP_SCR0_EX(%a6) # insert scaled exp
mov.l SRC_HI(%a0),FP_SCR0_HI(%a6) # copy hi(man)
mov.l SRC_LO(%a0),FP_SCR0_LO(%a6) # copy lo(man)
fmov.l L_SCR3(%a6),%fpcr # set FPCR
fmov.x FP_SCR0(%a6),%fp0 # force fop to be rounded
fmov.l &0x0,%fpcr # clear FPCR
fabs.x %fp0 # need absolute value
fcmp.b %fp0,&0x2 # did exponent increase?
fblt.w fout_sgl_exg # no; go finish NORM
bra.w fout_sgl_ovfl # yes; go handle overflow
tst.b 2+FP_SCR0_EX(%a6) # is EXOP negative?
beq.b fout_sd_exc_done # no
bset &0x7,FP_SCR0_EX(%a6) # yes
fout_sd_exc_done:
fmovm.x FP_SCR0(%a6),&0x40 # return EXOP in fp1
rts
#################################################################
# fmove.d out ###################################################
#################################################################
fout_dbl:
andi.b &0x30,%d0 # clear rnd prec
ori.b &d_mode*0x10,%d0 # insert dbl prec
mov.l %d0,L_SCR3(%a6) # save rnd prec,mode on stack
#
# operand is a normalized number. first, we check to see if the move out
# would cause either an underflow or overflow. these cases are handled
# separately. otherwise, set the FPCR to the proper rounding mode and
# execute the move.
#
mov.w SRC_EX(%a0),%d0 # extract exponent
andi.w &0x7fff,%d0 # strip sign
cmpi.w %d0,&DBL_HI # will operand overflow?
bgt.w fout_dbl_ovfl # yes; go handle OVFL
beq.w fout_dbl_may_ovfl # maybe; go handle possible OVFL
cmpi.w %d0,&DBL_LO # will operand underflow?
blt.w fout_dbl_unfl # yes; go handle underflow
#
# NORMs(in range) can be stored out by a simple "fmov.d"
# Unnormalized inputs can come through this point.
#
fout_dbl_exg:
fmovm.x SRC(%a0),&0x80 # fetch fop from stack
fmov.l L_SCR3(%a6),%fpcr # set FPCR
fmov.l &0x0,%fpsr # clear FPSR
fmov.d %fp0,L_SCR1(%a6) # store does convert and round
fmov.l &0x0,%fpcr # clear FPCR
fmov.l %fpsr,%d0 # save FPSR
or.w %d0,2+USER_FPSR(%a6) # set possible inex2/ainex
mov.l EXC_EA(%a6),%a1 # pass: dst addr
lea L_SCR1(%a6),%a0 # pass: src addr
movq.l &0x8,%d0 # pass: opsize is 8 bytes
bsr.l _dmem_write # store dbl fop to memory
tst.l %d1 # did dstore fail?
bne.l facc_out_d # yes
rts # no; so we're finished
#
# here, we know that the operand would UNFL if moved out to double prec,
# so, denorm and round and then use generic store double routine to
# write the value to memory.
#
fout_dbl_unfl:
bset &unfl_bit,FPSR_EXCEPT(%a6) # set UNFL
lea FP_SCR0(%a6),%a0 # pass: ptr to fop
bsr.l dst_dbl # convert to single prec
mov.l %d0,L_SCR1(%a6)
mov.l %d1,L_SCR2(%a6)
mov.l EXC_EA(%a6),%a1 # pass: dst addr
lea L_SCR1(%a6),%a0 # pass: src addr
movq.l &0x8,%d0 # pass: opsize is 8 bytes
bsr.l _dmem_write # store dbl fop to memory
tst.l %d1 # did dstore fail?
bne.l facc_out_d # yes
mov.b FPCR_ENABLE(%a6),%d1
andi.b &0x0a,%d1 # is UNFL or INEX enabled?
bne.w fout_sd_exc_unfl # yes
addq.l &0x4,%sp
rts
#
# it's definitely an overflow so call ovf_res to get the correct answer
#
fout_dbl_ovfl:
mov.w 2+SRC_LO(%a0),%d0
andi.w &0x7ff,%d0
bne.b fout_dbl_ovfl_inex2
ori.w &ovfl_inx_mask,2+USER_FPSR(%a6) # set ovfl/aovfl/ainex
bra.b fout_dbl_ovfl_cont
fout_dbl_ovfl_inex2:
ori.w &ovfinx_mask,2+USER_FPSR(%a6) # set ovfl/aovfl/ainex/inex2
fout_dbl_ovfl_cont:
mov.l %a0,-(%sp)
# call ovf_res() w/ dbl prec and the correct rnd mode to create the default
# overflow result. DON'T save the returned ccodes from ovf_res() since
# fmove out doesn't alter them.
tst.b SRC_EX(%a0) # is operand negative?
smi %d1 # set if so
mov.l L_SCR3(%a6),%d0 # pass: dbl prec,rnd mode
bsr.l ovf_res # calc OVFL result
fmovm.x (%a0),&0x80 # load default overflow result
fmov.d %fp0,L_SCR1(%a6) # store to double
mov.l EXC_EA(%a6),%a1 # pass: dst addr
lea L_SCR1(%a6),%a0 # pass: src addr
movq.l &0x8,%d0 # pass: opsize is 8 bytes
bsr.l _dmem_write # store dbl fop to memory
tst.l %d1 # did dstore fail?
bne.l facc_out_d # yes
mov.b FPCR_ENABLE(%a6),%d1
andi.b &0x0a,%d1 # is UNFL or INEX enabled?
bne.w fout_sd_exc_ovfl # yes
addq.l &0x4,%sp
rts
#
# move out MAY overflow:
# (1) force the exp to 0x3fff
# (2) do a move w/ appropriate rnd mode
# (3) if exp still equals zero, then insert original exponent
# for the correct result.
# if exp now equals one, then it overflowed so call ovf_res.
#
fout_dbl_may_ovfl:
mov.w SRC_EX(%a0),%d1 # fetch current sign
andi.w &0x8000,%d1 # keep it,clear exp
ori.w &0x3fff,%d1 # insert exp = 0
mov.w %d1,FP_SCR0_EX(%a6) # insert scaled exp
mov.l SRC_HI(%a0),FP_SCR0_HI(%a6) # copy hi(man)
mov.l SRC_LO(%a0),FP_SCR0_LO(%a6) # copy lo(man)
fmov.l L_SCR3(%a6),%fpcr # set FPCR
fmov.x FP_SCR0(%a6),%fp0 # force fop to be rounded
fmov.l &0x0,%fpcr # clear FPCR
fabs.x %fp0 # need absolute value
fcmp.b %fp0,&0x2 # did exponent increase?
fblt.w fout_dbl_exg # no; go finish NORM
bra.w fout_dbl_ovfl # yes; go handle overflow
dst_dbl:
clr.l %d0 # clear d0
mov.w FTEMP_EX(%a0),%d0 # get exponent
subi.w &EXT_BIAS,%d0 # subtract extended precision bias
addi.w &DBL_BIAS,%d0 # add double precision bias
tst.b FTEMP_HI(%a0) # is number a denorm?
bmi.b dst_get_dupper # no
subq.w &0x1,%d0 # yes; denorm bias = DBL_BIAS - 1
dst_get_dupper:
swap %d0 # d0 now in upper word
lsl.l &0x4,%d0 # d0 in proper place for dbl prec exp
tst.b FTEMP_EX(%a0) # test sign
bpl.b dst_get_dman # if postive, go process mantissa
bset &0x1f,%d0 # if negative, set sign
dst_get_dman:
mov.l FTEMP_HI(%a0),%d1 # get ms mantissa
bfextu %d1{&1:&20},%d1 # get upper 20 bits of ms
or.l %d1,%d0 # put these bits in ms word of double
mov.l %d0,L_SCR1(%a6) # put the new exp back on the stack
mov.l FTEMP_HI(%a0),%d1 # get ms mantissa
mov.l &21,%d0 # load shift count
lsl.l %d0,%d1 # put lower 11 bits in upper bits
mov.l %d1,L_SCR2(%a6) # build lower lword in memory
mov.l FTEMP_LO(%a0),%d1 # get ls mantissa
bfextu %d1{&0:&21},%d0 # get ls 21 bits of double
mov.l L_SCR2(%a6),%d1
or.l %d0,%d1 # put them in double result
mov.l L_SCR1(%a6),%d0
rts
dst_sgl:
clr.l %d0
mov.w FTEMP_EX(%a0),%d0 # get exponent
subi.w &EXT_BIAS,%d0 # subtract extended precision bias
addi.w &SGL_BIAS,%d0 # add single precision bias
tst.b FTEMP_HI(%a0) # is number a denorm?
bmi.b dst_get_supper # no
subq.w &0x1,%d0 # yes; denorm bias = SGL_BIAS - 1
dst_get_supper:
swap %d0 # put exp in upper word of d0
lsl.l &0x7,%d0 # shift it into single exp bits
tst.b FTEMP_EX(%a0) # test sign
bpl.b dst_get_sman # if positive, continue
bset &0x1f,%d0 # if negative, put in sign first
dst_get_sman:
mov.l FTEMP_HI(%a0),%d1 # get ms mantissa
andi.l &0x7fffff00,%d1 # get upper 23 bits of ms
lsr.l &0x8,%d1 # and put them flush right
or.l %d1,%d0 # put these bits in ms word of single
rts
##############################################################################
fout_pack:
bsr.l _calc_ea_fout # fetch the <ea>
mov.l %a0,-(%sp)
mov.b STAG(%a6),%d0 # fetch input type
bne.w fout_pack_not_norm # input is not NORM
# bindec is currently scrambling FP_SRC for denorm inputs.
# we'll have to change this, but for now, tough luck!!!
bsr.l bindec # convert xprec to packed
# add the extra condition that only if the k-factor was zero, too, should
# we zero the exponent
tst.l %d0
bne.b fout_pack_set
# "mantissa" is all zero which means that the answer is zero. but, the '040
# algorithm allows the exponent to be non-zero. the 881/2 do not. therefore,
# if the mantissa is zero, I will zero the exponent, too.
# the question now is whether the exponents sign bit is allowed to be non-zero
# for a zero, also...
andi.w &0xf000,FP_SCR0(%a6)
bsr.l _dmem_write # write ext prec number to memory
tst.l %d1 # did dstore fail?
bne.w fout_ext_err # yes
rts
# we don't want to do the write if the exception occurred in supervisor mode
# so _mem_write2() handles this for us.
fout_pack_a7:
bsr.l _mem_write2 # write ext prec number to memory
tst.l %d1 # did dstore fail?
bne.w fout_ext_err # yes
rts
fout_pack_not_norm:
cmpi.b %d0,&DENORM # is it a DENORM?
beq.w fout_pack_norm # yes
lea FP_SRC(%a6),%a0
clr.w 2+FP_SRC_EX(%a6)
cmpi.b %d0,&SNAN # is it an SNAN?
beq.b fout_pack_snan # yes
bra.b fout_pack_write # no
fout_pack_snan:
ori.w &snaniop2_mask,FPSR_EXCEPT(%a6) # set SNAN/AIOP
bset &0x6,FP_SRC_HI(%a6) # set snan bit
bra.b fout_pack_write
#########################################################################
# XDEF **************************************************************** #
# fmul(): emulates the fmul instruction #
# fsmul(): emulates the fsmul instruction #
# fdmul(): emulates the fdmul instruction #
# #
# XREF **************************************************************** #
# scale_to_zero_src() - scale src exponent to zero #
# scale_to_zero_dst() - scale dst exponent to zero #
# unf_res() - return default underflow result #
# ovf_res() - return default overflow result #
# res_qnan() - return QNAN result #
# res_snan() - return SNAN result #
# #
# INPUT *************************************************************** #
# a0 = pointer to extended precision source operand #
# a1 = pointer to extended precision destination operand #
# d0 rnd prec,mode #
# #
# OUTPUT ************************************************************** #
# fp0 = result #
# fp1 = EXOP (if exception occurred) #
# #
# ALGORITHM *********************************************************** #
# Handle NANs, infinities, and zeroes as special cases. Divide #
# norms/denorms into ext/sgl/dbl precision. #
# For norms/denorms, scale the exponents such that a multiply #
# instruction won't cause an exception. Use the regular fmul to #
# compute a result. Check if the regular operands would have taken #
# an exception. If so, return the default overflow/underflow result #
# and return the EXOP if exceptions are enabled. Else, scale the #
# result operand to the proper exponent. #
# #
#########################################################################
align 0x10
tbl_fmul_ovfl:
long 0x3fff - 0x7ffe # ext_max
long 0x3fff - 0x407e # sgl_max
long 0x3fff - 0x43fe # dbl_max
tbl_fmul_unfl:
long 0x3fff + 0x0001 # ext_unfl
long 0x3fff - 0x3f80 # sgl_unfl
long 0x3fff - 0x3c00 # dbl_unfl
mov.w 2+L_SCR3(%a6),%d1 # fetch precision
lsr.b &0x6,%d1 # shift to lo bits
mov.l (%sp)+,%d0 # load S.F.
cmp.l %d0,(tbl_fmul_ovfl.w,%pc,%d1.w*4) # would result ovfl?
beq.w fmul_may_ovfl # result may rnd to overflow
blt.w fmul_ovfl # result will overflow
cmp.l %d0,(tbl_fmul_unfl.w,%pc,%d1.w*4) # would result unfl?
beq.w fmul_may_unfl # result may rnd to no unfl
bgt.w fmul_unfl # result will underflow
#
# NORMAL:
# - the result of the multiply operation will neither overflow nor underflow.
# - do the multiply to the proper precision and rounding mode.
# - scale the result exponent using the scale factor. if both operands were
# normalized then we really don't need to go through this scaling. but for now,
# this will do.
#
fmul_normal:
fmovm.x FP_SCR1(%a6),&0x80 # load dst operand
fmov.l L_SCR3(%a6),%fpcr # set FPCR
fmov.l &0x0,%fpsr # clear FPSR
fmul.x FP_SCR0(%a6),%fp0 # execute multiply
fmov.l %fpsr,%d1 # save status
fmov.l &0x0,%fpcr # clear FPCR
or.l %d1,USER_FPSR(%a6) # save INEX2,N
fmul_normal_exit:
fmovm.x &0x80,FP_SCR0(%a6) # store out result
mov.l %d2,-(%sp) # save d2
mov.w FP_SCR0_EX(%a6),%d1 # load {sgn,exp}
mov.l %d1,%d2 # make a copy
andi.l &0x7fff,%d1 # strip sign
andi.w &0x8000,%d2 # keep old sign
sub.l %d0,%d1 # add scale factor
or.w %d2,%d1 # concat old sign,new exp
mov.w %d1,FP_SCR0_EX(%a6) # insert new exponent
mov.l (%sp)+,%d2 # restore d2
fmovm.x FP_SCR0(%a6),&0x80 # return default result in fp0
rts
#
# OVERFLOW:
# - the result of the multiply operation is an overflow.
# - do the multiply to the proper precision and rounding mode in order to
# set the inexact bits.
# - calculate the default result and return it in fp0.
# - if overflow or inexact is enabled, we need a multiply result rounded to
# extended precision. if the original operation was extended, then we have this
# result. if the original operation was single or double, we have to do another
# multiply using extended precision and the correct rounding mode. the result
# of this operation then has its exponent scaled by -0x6000 to create the
# exceptional operand.
#
fmul_ovfl:
fmovm.x FP_SCR1(%a6),&0x80 # load dst operand
fmov.l L_SCR3(%a6),%fpcr # set FPCR
fmov.l &0x0,%fpsr # clear FPSR
fmul.x FP_SCR0(%a6),%fp0 # execute multiply
fmov.l %fpsr,%d1 # save status
fmov.l &0x0,%fpcr # clear FPCR
or.l %d1,USER_FPSR(%a6) # save INEX2,N
# save setting this until now because this is where fmul_may_ovfl may jump in
fmul_ovfl_tst:
or.l &ovfl_inx_mask,USER_FPSR(%a6) # set ovfl/aovfl/ainex
mov.b FPCR_ENABLE(%a6),%d1
andi.b &0x13,%d1 # is OVFL or INEX enabled?
bne.b fmul_ovfl_ena # yes
# calculate the default result
fmul_ovfl_dis:
btst &neg_bit,FPSR_CC(%a6) # is result negative?
sne %d1 # set sign param accordingly
mov.l L_SCR3(%a6),%d0 # pass rnd prec,mode
bsr.l ovf_res # calculate default result
or.b %d0,FPSR_CC(%a6) # set INF,N if applicable
fmovm.x (%a0),&0x80 # return default result in fp0
rts
#
# OVFL is enabled; Create EXOP:
# - if precision is extended, then we have the EXOP. simply bias the exponent
# with an extra -0x6000. if the precision is single or double, we need to
# calculate a result rounded to extended precision.
#
fmul_ovfl_ena:
mov.l L_SCR3(%a6),%d1
andi.b &0xc0,%d1 # test the rnd prec
bne.b fmul_ovfl_ena_sd # it's sgl or dbl
fmul_ovfl_ena_cont:
fmovm.x &0x80,FP_SCR0(%a6) # move result to stack
mov.l %d2,-(%sp) # save d2
mov.w FP_SCR0_EX(%a6),%d1 # fetch {sgn,exp}
mov.w %d1,%d2 # make a copy
andi.l &0x7fff,%d1 # strip sign
sub.l %d0,%d1 # add scale factor
subi.l &0x6000,%d1 # subtract bias
andi.w &0x7fff,%d1 # clear sign bit
andi.w &0x8000,%d2 # keep old sign
or.w %d2,%d1 # concat old sign,new exp
mov.w %d1,FP_SCR0_EX(%a6) # insert new exponent
mov.l (%sp)+,%d2 # restore d2
fmovm.x FP_SCR0(%a6),&0x40 # return EXOP in fp1
bra.b fmul_ovfl_dis
#
# may OVERFLOW:
# - the result of the multiply operation MAY overflow.
# - do the multiply to the proper precision and rounding mode in order to
# set the inexact bits.
# - calculate the default result and return it in fp0.
#
fmul_may_ovfl:
fmovm.x FP_SCR1(%a6),&0x80 # load dst op
fmov.l L_SCR3(%a6),%fpcr # set FPCR
fmov.l &0x0,%fpsr # clear FPSR
fmul.x FP_SCR0(%a6),%fp0 # execute multiply
fmov.l %fpsr,%d1 # save status
fmov.l &0x0,%fpcr # clear FPCR
or.l %d1,USER_FPSR(%a6) # save INEX2,N
fabs.x %fp0,%fp1 # make a copy of result
fcmp.b %fp1,&0x2 # is |result| >= 2.b?
fbge.w fmul_ovfl_tst # yes; overflow has occurred
# no, it didn't overflow; we have correct result
bra.w fmul_normal_exit
#
# UNDERFLOW:
# - the result of the multiply operation is an underflow.
# - do the multiply to the proper precision and rounding mode in order to
# set the inexact bits.
# - calculate the default result and return it in fp0.
# - if overflow or inexact is enabled, we need a multiply result rounded to
# extended precision. if the original operation was extended, then we have this
# result. if the original operation was single or double, we have to do another
# multiply using extended precision and the correct rounding mode. the result
# of this operation then has its exponent scaled by -0x6000 to create the
# exceptional operand.
#
fmul_unfl:
bset &unfl_bit,FPSR_EXCEPT(%a6) # set unfl exc bit
# for fun, let's use only extended precision, round to zero. then, let
# the unf_res() routine figure out all the rest.
# will we get the correct answer.
fmovm.x FP_SCR1(%a6),&0x80 # load dst operand
fmov.l &rz_mode*0x10,%fpcr # set FPCR
fmov.l &0x0,%fpsr # clear FPSR
fmul.x FP_SCR0(%a6),%fp0 # execute multiply
fmov.l %fpsr,%d1 # save status
fmov.l &0x0,%fpcr # clear FPCR
or.l %d1,USER_FPSR(%a6) # save INEX2,N
mov.b FPCR_ENABLE(%a6),%d1
andi.b &0x0b,%d1 # is UNFL or INEX enabled?
bne.b fmul_unfl_ena # yes
fmul_unfl_dis:
fmovm.x &0x80,FP_SCR0(%a6) # store out result
lea FP_SCR0(%a6),%a0 # pass: result addr
mov.l L_SCR3(%a6),%d1 # pass: rnd prec,mode
bsr.l unf_res # calculate default result
or.b %d0,FPSR_CC(%a6) # unf_res2 may have set 'Z'
fmovm.x FP_SCR0(%a6),&0x80 # return default result in fp0
rts
#
# UNFL is enabled.
#
fmul_unfl_ena:
fmovm.x FP_SCR1(%a6),&0x40 # load dst op
mov.l L_SCR3(%a6),%d1
andi.b &0xc0,%d1 # is precision extended?
bne.b fmul_unfl_ena_sd # no, sgl or dbl
# if the rnd mode is anything but RZ, then we have to re-do the above
# multiplication because we used RZ for all.
fmov.l L_SCR3(%a6),%fpcr # set FPCR
fmovm.x &0x40,FP_SCR0(%a6) # save result to stack
mov.l %d2,-(%sp) # save d2
mov.w FP_SCR0_EX(%a6),%d1 # fetch {sgn,exp}
mov.l %d1,%d2 # make a copy
andi.l &0x7fff,%d1 # strip sign
andi.w &0x8000,%d2 # keep old sign
sub.l %d0,%d1 # add scale factor
addi.l &0x6000,%d1 # add bias
andi.w &0x7fff,%d1
or.w %d2,%d1 # concat old sign,new exp
mov.w %d1,FP_SCR0_EX(%a6) # insert new exponent
mov.l (%sp)+,%d2 # restore d2
fmovm.x FP_SCR0(%a6),&0x40 # return EXOP in fp1
bra.w fmul_unfl_dis
fmul_unfl_ena_sd:
mov.l L_SCR3(%a6),%d1
andi.b &0x30,%d1 # use only rnd mode
fmov.l %d1,%fpcr # set FPCR
bra.b fmul_unfl_ena_cont
# MAY UNDERFLOW:
# -use the correct rounding mode and precision. this code favors operations
# that do not underflow.
fmul_may_unfl:
fmovm.x FP_SCR1(%a6),&0x80 # load dst operand
fmov.l L_SCR3(%a6),%fpcr # set FPCR
fmov.l &0x0,%fpsr # clear FPSR
fmul.x FP_SCR0(%a6),%fp0 # execute multiply
fmov.l %fpsr,%d1 # save status
fmov.l &0x0,%fpcr # clear FPCR
or.l %d1,USER_FPSR(%a6) # save INEX2,N
fabs.x %fp0,%fp1 # make a copy of result
fcmp.b %fp1,&0x2 # is |result| > 2.b?
fbgt.w fmul_normal_exit # no; no underflow occurred
fblt.w fmul_unfl # yes; underflow occurred
#
# we still don't know if underflow occurred. result is ~ equal to 2. but,
# we don't know if the result was an underflow that rounded up to a 2 or
# a normalized number that rounded down to a 2. so, redo the entire operation
# using RZ as the rounding mode to see what the pre-rounded result is.
# this case should be relatively rare.
#
fmovm.x FP_SCR1(%a6),&0x40 # load dst operand
#
# Multiply: inputs are not both normalized; what are they?
#
fmul_not_norm:
mov.w (tbl_fmul_op.b,%pc,%d1.w*2),%d1
jmp (tbl_fmul_op.b,%pc,%d1.w)
swbeg &48
tbl_fmul_op:
short fmul_norm - tbl_fmul_op # NORM x NORM
short fmul_zero - tbl_fmul_op # NORM x ZERO
short fmul_inf_src - tbl_fmul_op # NORM x INF
short fmul_res_qnan - tbl_fmul_op # NORM x QNAN
short fmul_norm - tbl_fmul_op # NORM x DENORM
short fmul_res_snan - tbl_fmul_op # NORM x SNAN
short tbl_fmul_op - tbl_fmul_op #
short tbl_fmul_op - tbl_fmul_op #
short fmul_zero - tbl_fmul_op # ZERO x NORM
short fmul_zero - tbl_fmul_op # ZERO x ZERO
short fmul_res_operr - tbl_fmul_op # ZERO x INF
short fmul_res_qnan - tbl_fmul_op # ZERO x QNAN
short fmul_zero - tbl_fmul_op # ZERO x DENORM
short fmul_res_snan - tbl_fmul_op # ZERO x SNAN
short tbl_fmul_op - tbl_fmul_op #
short tbl_fmul_op - tbl_fmul_op #
short fmul_inf_dst - tbl_fmul_op # INF x NORM
short fmul_res_operr - tbl_fmul_op # INF x ZERO
short fmul_inf_dst - tbl_fmul_op # INF x INF
short fmul_res_qnan - tbl_fmul_op # INF x QNAN
short fmul_inf_dst - tbl_fmul_op # INF x DENORM
short fmul_res_snan - tbl_fmul_op # INF x SNAN
short tbl_fmul_op - tbl_fmul_op #
short tbl_fmul_op - tbl_fmul_op #
short fmul_res_qnan - tbl_fmul_op # QNAN x NORM
short fmul_res_qnan - tbl_fmul_op # QNAN x ZERO
short fmul_res_qnan - tbl_fmul_op # QNAN x INF
short fmul_res_qnan - tbl_fmul_op # QNAN x QNAN
short fmul_res_qnan - tbl_fmul_op # QNAN x DENORM
short fmul_res_snan - tbl_fmul_op # QNAN x SNAN
short tbl_fmul_op - tbl_fmul_op #
short tbl_fmul_op - tbl_fmul_op #
short fmul_norm - tbl_fmul_op # NORM x NORM
short fmul_zero - tbl_fmul_op # NORM x ZERO
short fmul_inf_src - tbl_fmul_op # NORM x INF
short fmul_res_qnan - tbl_fmul_op # NORM x QNAN
short fmul_norm - tbl_fmul_op # NORM x DENORM
short fmul_res_snan - tbl_fmul_op # NORM x SNAN
short tbl_fmul_op - tbl_fmul_op #
short tbl_fmul_op - tbl_fmul_op #
short fmul_res_snan - tbl_fmul_op # SNAN x NORM
short fmul_res_snan - tbl_fmul_op # SNAN x ZERO
short fmul_res_snan - tbl_fmul_op # SNAN x INF
short fmul_res_snan - tbl_fmul_op # SNAN x QNAN
short fmul_res_snan - tbl_fmul_op # SNAN x DENORM
short fmul_res_snan - tbl_fmul_op # SNAN x SNAN
short tbl_fmul_op - tbl_fmul_op #
short tbl_fmul_op - tbl_fmul_op #
#
# Multiply: (Zero x Zero) || (Zero x norm) || (Zero x denorm)
#
global fmul_zero # global for fsglmul
fmul_zero:
mov.b SRC_EX(%a0),%d0 # exclusive or the signs
mov.b DST_EX(%a1),%d1
eor.b %d0,%d1
bpl.b fmul_zero_p # result ZERO is pos.
fmul_zero_n:
fmov.s &0x80000000,%fp0 # load -ZERO
mov.b &z_bmask+neg_bmask,FPSR_CC(%a6) # set Z/N
rts
fmul_zero_p:
fmov.s &0x00000000,%fp0 # load +ZERO
mov.b &z_bmask,FPSR_CC(%a6) # set Z
rts
#
# Multiply: (inf x inf) || (inf x norm) || (inf x denorm)
#
# Note: The j-bit for an infinity is a don't-care. However, to be
# strictly compatible w/ the 68881/882, we make sure to return an
# INF w/ the j-bit set if the input INF j-bit was set. Destination
# INFs take priority.
#
global fmul_inf_dst # global for fsglmul
fmul_inf_dst:
fmovm.x DST(%a1),&0x80 # return INF result in fp0
mov.b SRC_EX(%a0),%d0 # exclusive or the signs
mov.b DST_EX(%a1),%d1
eor.b %d0,%d1
bpl.b fmul_inf_dst_p # result INF is pos.
fmul_inf_dst_n:
fabs.x %fp0 # clear result sign
fneg.x %fp0 # set result sign
mov.b &inf_bmask+neg_bmask,FPSR_CC(%a6) # set INF/N
rts
fmul_inf_dst_p:
fabs.x %fp0 # clear result sign
mov.b &inf_bmask,FPSR_CC(%a6) # set INF
rts
global fmul_inf_src # global for fsglmul
fmul_inf_src:
fmovm.x SRC(%a0),&0x80 # return INF result in fp0
mov.b SRC_EX(%a0),%d0 # exclusive or the signs
mov.b DST_EX(%a1),%d1
eor.b %d0,%d1
bpl.b fmul_inf_dst_p # result INF is pos.
bra.b fmul_inf_dst_n
#########################################################################
# XDEF **************************************************************** #
# fin(): emulates the fmove instruction #
# fsin(): emulates the fsmove instruction #
# fdin(): emulates the fdmove instruction #
# #
# XREF **************************************************************** #
# norm() - normalize mantissa for EXOP on denorm #
# scale_to_zero_src() - scale src exponent to zero #
# ovf_res() - return default overflow result #
# unf_res() - return default underflow result #
# res_qnan_1op() - return QNAN result #
# res_snan_1op() - return SNAN result #
# #
# INPUT *************************************************************** #
# a0 = pointer to extended precision source operand #
# d0 = round prec/mode #
# #
# OUTPUT ************************************************************** #
# fp0 = result #
# fp1 = EXOP (if exception occurred) #
# #
# ALGORITHM *********************************************************** #
# Handle NANs, infinities, and zeroes as special cases. Divide #
# norms into extended, single, and double precision. #
# Norms can be emulated w/ a regular fmove instruction. For #
# sgl/dbl, must scale exponent and perform an "fmove". Check to see #
# if the result would have overflowed/underflowed. If so, use unf_res() #
# or ovf_res() to return the default result. Also return EXOP if #
# exception is enabled. If no exception, return the default result. #
# Unnorms don't pass through here. #
# #
#########################################################################
global fsin
fsin:
andi.b &0x30,%d0 # clear rnd prec
ori.b &s_mode*0x10,%d0 # insert sgl precision
bra.b fin
global fin
fin:
mov.l %d0,L_SCR3(%a6) # store rnd info
mov.b STAG(%a6),%d1 # fetch src optype tag
bne.w fin_not_norm # optimize on non-norm input
#
# FP MOVE IN: NORMs and DENORMs ONLY!
#
fin_norm:
andi.b &0xc0,%d0 # is precision extended?
bne.w fin_not_ext # no, so go handle dbl or sgl
#
# precision selected is extended. so...we cannot get an underflow
# or overflow because of rounding to the correct precision. so...
# skip the scaling and unscaling...
#
tst.b SRC_EX(%a0) # is the operand negative?
bpl.b fin_norm_done # no
bset &neg_bit,FPSR_CC(%a6) # yes, so set 'N' ccode bit
fin_norm_done:
fmovm.x SRC(%a0),&0x80 # return result in fp0
rts
#
# for an extended precision DENORM, the UNFL exception bit is set
# the accrued bit is NOT set in this instance(no inexactness!)
#
fin_denorm:
andi.b &0xc0,%d0 # is precision extended?
bne.w fin_not_ext # no, so go handle dbl or sgl
bset &unfl_bit,FPSR_EXCEPT(%a6) # set unfl exc bit
tst.b SRC_EX(%a0) # is the operand negative?
bpl.b fin_denorm_done # no
bset &neg_bit,FPSR_CC(%a6) # yes, so set 'N' ccode bit
fin_denorm_done:
fmovm.x SRC(%a0),&0x80 # return result in fp0
btst &unfl_bit,FPCR_ENABLE(%a6) # is UNFL enabled?
bne.b fin_denorm_unfl_ena # yes
rts
#
# the input is an extended DENORM and underflow is enabled in the FPCR.
# normalize the mantissa and add the bias of 0x6000 to the resulting negative
# exponent and insert back into the operand.
#
fin_denorm_unfl_ena:
mov.w SRC_EX(%a0),FP_SCR0_EX(%a6)
mov.l SRC_HI(%a0),FP_SCR0_HI(%a6)
mov.l SRC_LO(%a0),FP_SCR0_LO(%a6)
lea FP_SCR0(%a6),%a0 # pass: ptr to operand
bsr.l norm # normalize result
neg.w %d0 # new exponent = -(shft val)
addi.w &0x6000,%d0 # add new bias to exponent
mov.w FP_SCR0_EX(%a6),%d1 # fetch old sign,exp
andi.w &0x8000,%d1 # keep old sign
andi.w &0x7fff,%d0 # clear sign position
or.w %d1,%d0 # concat new exo,old sign
mov.w %d0,FP_SCR0_EX(%a6) # insert new exponent
fmovm.x FP_SCR0(%a6),&0x40 # return EXOP in fp1
rts
#
# operand is to be rounded to single or double precision
#
fin_not_ext:
cmpi.b %d0,&s_mode*0x10 # separate sgl/dbl prec
bne.b fin_dbl
#
# operand is to be rounded to single precision
#
fin_sgl:
mov.w SRC_EX(%a0),FP_SCR0_EX(%a6)
mov.l SRC_HI(%a0),FP_SCR0_HI(%a6)
mov.l SRC_LO(%a0),FP_SCR0_LO(%a6)
bsr.l scale_to_zero_src # calculate scale factor
cmpi.l %d0,&0x3fff-0x3f80 # will move in underflow?
bge.w fin_sd_unfl # yes; go handle underflow
cmpi.l %d0,&0x3fff-0x407e # will move in overflow?
beq.w fin_sd_may_ovfl # maybe; go check
blt.w fin_sd_ovfl # yes; go handle overflow
#
# operand will NOT overflow or underflow when moved into the fp reg file
#
fin_sd_normal:
fmov.l &0x0,%fpsr # clear FPSR
fmov.l L_SCR3(%a6),%fpcr # set FPCR
fmov.x FP_SCR0(%a6),%fp0 # perform move
fmov.l %fpsr,%d1 # save FPSR
fmov.l &0x0,%fpcr # clear FPCR
or.l %d1,USER_FPSR(%a6) # save INEX2,N
fin_sd_normal_exit:
mov.l %d2,-(%sp) # save d2
fmovm.x &0x80,FP_SCR0(%a6) # store out result
mov.w FP_SCR0_EX(%a6),%d1 # load {sgn,exp}
mov.w %d1,%d2 # make a copy
andi.l &0x7fff,%d1 # strip sign
sub.l %d0,%d1 # add scale factor
andi.w &0x8000,%d2 # keep old sign
or.w %d1,%d2 # concat old sign,new exponent
mov.w %d2,FP_SCR0_EX(%a6) # insert new exponent
mov.l (%sp)+,%d2 # restore d2
fmovm.x FP_SCR0(%a6),&0x80 # return result in fp0
rts
#
# operand is to be rounded to double precision
#
fin_dbl:
mov.w SRC_EX(%a0),FP_SCR0_EX(%a6)
mov.l SRC_HI(%a0),FP_SCR0_HI(%a6)
mov.l SRC_LO(%a0),FP_SCR0_LO(%a6)
bsr.l scale_to_zero_src # calculate scale factor
cmpi.l %d0,&0x3fff-0x3c00 # will move in underflow?
bge.w fin_sd_unfl # yes; go handle underflow
cmpi.l %d0,&0x3fff-0x43fe # will move in overflow?
beq.w fin_sd_may_ovfl # maybe; go check
blt.w fin_sd_ovfl # yes; go handle overflow
bra.w fin_sd_normal # no; ho handle normalized op
#
# operand WILL underflow when moved in to the fp register file
#
fin_sd_unfl:
bset &unfl_bit,FPSR_EXCEPT(%a6) # set unfl exc bit
tst.b FP_SCR0_EX(%a6) # is operand negative?
bpl.b fin_sd_unfl_tst
bset &neg_bit,FPSR_CC(%a6) # set 'N' ccode bit
# if underflow or inexact is enabled, then go calculate the EXOP first.
fin_sd_unfl_tst:
mov.b FPCR_ENABLE(%a6),%d1
andi.b &0x0b,%d1 # is UNFL or INEX enabled?
bne.b fin_sd_unfl_ena # yes
fin_sd_unfl_dis:
lea FP_SCR0(%a6),%a0 # pass: result addr
mov.l L_SCR3(%a6),%d1 # pass: rnd prec,mode
bsr.l unf_res # calculate default result
or.b %d0,FPSR_CC(%a6) # unf_res may have set 'Z'
fmovm.x FP_SCR0(%a6),&0x80 # return default result in fp0
rts
#
# operand will underflow AND underflow or inexact is enabled.
# therefore, we must return the result rounded to extended precision.
#
fin_sd_unfl_ena:
mov.l FP_SCR0_HI(%a6),FP_SCR1_HI(%a6)
mov.l FP_SCR0_LO(%a6),FP_SCR1_LO(%a6)
mov.w FP_SCR0_EX(%a6),%d1 # load current exponent
mov.l %d2,-(%sp) # save d2
mov.w %d1,%d2 # make a copy
andi.l &0x7fff,%d1 # strip sign
sub.l %d0,%d1 # subtract scale factor
andi.w &0x8000,%d2 # extract old sign
addi.l &0x6000,%d1 # add new bias
andi.w &0x7fff,%d1
or.w %d1,%d2 # concat old sign,new exp
mov.w %d2,FP_SCR1_EX(%a6) # insert new exponent
fmovm.x FP_SCR1(%a6),&0x40 # return EXOP in fp1
mov.l (%sp)+,%d2 # restore d2
bra.b fin_sd_unfl_dis
#
# operand WILL overflow.
#
fin_sd_ovfl:
fmov.l &0x0,%fpsr # clear FPSR
fmov.l L_SCR3(%a6),%fpcr # set FPCR
fmov.x FP_SCR0(%a6),%fp0 # perform move
fmov.l &0x0,%fpcr # clear FPCR
fmov.l %fpsr,%d1 # save FPSR
or.l %d1,USER_FPSR(%a6) # save INEX2,N
fin_sd_ovfl_tst:
or.l &ovfl_inx_mask,USER_FPSR(%a6) # set ovfl/aovfl/ainex
mov.b FPCR_ENABLE(%a6),%d1
andi.b &0x13,%d1 # is OVFL or INEX enabled?
bne.b fin_sd_ovfl_ena # yes
#
# OVFL is not enabled; therefore, we must create the default result by
# calling ovf_res().
#
fin_sd_ovfl_dis:
btst &neg_bit,FPSR_CC(%a6) # is result negative?
sne %d1 # set sign param accordingly
mov.l L_SCR3(%a6),%d0 # pass: prec,mode
bsr.l ovf_res # calculate default result
or.b %d0,FPSR_CC(%a6) # set INF,N if applicable
fmovm.x (%a0),&0x80 # return default result in fp0
rts
#
# OVFL is enabled.
# the INEX2 bit has already been updated by the round to the correct precision.
# now, round to extended(and don't alter the FPSR).
#
fin_sd_ovfl_ena:
mov.l %d2,-(%sp) # save d2
mov.w FP_SCR0_EX(%a6),%d1 # fetch {sgn,exp}
mov.l %d1,%d2 # make a copy
andi.l &0x7fff,%d1 # strip sign
andi.w &0x8000,%d2 # keep old sign
sub.l %d0,%d1 # add scale factor
sub.l &0x6000,%d1 # subtract bias
andi.w &0x7fff,%d1
or.w %d2,%d1
mov.w %d1,FP_SCR0_EX(%a6) # insert new exponent
mov.l (%sp)+,%d2 # restore d2
fmovm.x FP_SCR0(%a6),&0x40 # return EXOP in fp1
bra.b fin_sd_ovfl_dis
#
# the move in MAY overflow. so...
#
fin_sd_may_ovfl:
fmov.l &0x0,%fpsr # clear FPSR
fmov.l L_SCR3(%a6),%fpcr # set FPCR
fmov.x FP_SCR0(%a6),%fp0 # perform the move
fmov.l %fpsr,%d1 # save status
fmov.l &0x0,%fpcr # clear FPCR
or.l %d1,USER_FPSR(%a6) # save INEX2,N
fabs.x %fp0,%fp1 # make a copy of result
fcmp.b %fp1,&0x2 # is |result| >= 2.b?
fbge.w fin_sd_ovfl_tst # yes; overflow has occurred
# no, it didn't overflow; we have correct result
bra.w fin_sd_normal_exit
#
# operand is not a NORM: check its optype and branch accordingly
#
fin_not_norm:
cmpi.b %d1,&DENORM # weed out DENORM
beq.w fin_denorm
cmpi.b %d1,&SNAN # weed out SNANs
beq.l res_snan_1op
cmpi.b %d1,&QNAN # weed out QNANs
beq.l res_qnan_1op
#
# do the fmove in; at this point, only possible ops are ZERO and INF.
# use fmov to determine ccodes.
# prec:mode should be zero at this point but it won't affect answer anyways.
#
fmov.x SRC(%a0),%fp0 # do fmove in
fmov.l %fpsr,%d0 # no exceptions possible
rol.l &0x8,%d0 # put ccodes in lo byte
mov.b %d0,FPSR_CC(%a6) # insert correct ccodes
rts
#########################################################################
# XDEF **************************************************************** #
# fdiv(): emulates the fdiv instruction #
# fsdiv(): emulates the fsdiv instruction #
# fddiv(): emulates the fddiv instruction #
# #
# XREF **************************************************************** #
# scale_to_zero_src() - scale src exponent to zero #
# scale_to_zero_dst() - scale dst exponent to zero #
# unf_res() - return default underflow result #
# ovf_res() - return default overflow result #
# res_qnan() - return QNAN result #
# res_snan() - return SNAN result #
# #
# INPUT *************************************************************** #
# a0 = pointer to extended precision source operand #
# a1 = pointer to extended precision destination operand #
# d0 rnd prec,mode #
# #
# OUTPUT ************************************************************** #
# fp0 = result #
# fp1 = EXOP (if exception occurred) #
# #
# ALGORITHM *********************************************************** #
# Handle NANs, infinities, and zeroes as special cases. Divide #
# norms/denorms into ext/sgl/dbl precision. #
# For norms/denorms, scale the exponents such that a divide #
# instruction won't cause an exception. Use the regular fdiv to #
# compute a result. Check if the regular operands would have taken #
# an exception. If so, return the default overflow/underflow result #
# and return the EXOP if exceptions are enabled. Else, scale the #
# result operand to the proper exponent. #
# #
#########################################################################
align 0x10
tbl_fdiv_unfl:
long 0x3fff - 0x0000 # ext_unfl
long 0x3fff - 0x3f81 # sgl_unfl
long 0x3fff - 0x3c01 # dbl_unfl
tbl_fdiv_ovfl:
long 0x3fff - 0x7ffe # ext overflow exponent
long 0x3fff - 0x407e # sgl overflow exponent
long 0x3fff - 0x43fe # dbl overflow exponent
mov.w 2+L_SCR3(%a6),%d1 # fetch precision
lsr.b &0x6,%d1 # shift to lo bits
mov.l (%sp)+,%d0 # load S.F.
cmp.l %d0,(tbl_fdiv_ovfl.b,%pc,%d1.w*4) # will result overflow?
ble.w fdiv_may_ovfl # result will overflow
cmp.l %d0,(tbl_fdiv_unfl.w,%pc,%d1.w*4) # will result underflow?
beq.w fdiv_may_unfl # maybe
bgt.w fdiv_unfl # yes; go handle underflow
fdiv_normal:
fmovm.x FP_SCR1(%a6),&0x80 # load dst op
fmov.l L_SCR3(%a6),%fpcr # save FPCR
fmov.l &0x0,%fpsr # clear FPSR
fdiv.x FP_SCR0(%a6),%fp0 # perform divide
fmov.l %fpsr,%d1 # save FPSR
fmov.l &0x0,%fpcr # clear FPCR
or.l %d1,USER_FPSR(%a6) # save INEX2,N
fdiv_normal_exit:
fmovm.x &0x80,FP_SCR0(%a6) # store result on stack
mov.l %d2,-(%sp) # store d2
mov.w FP_SCR0_EX(%a6),%d1 # load {sgn,exp}
mov.l %d1,%d2 # make a copy
andi.l &0x7fff,%d1 # strip sign
andi.w &0x8000,%d2 # keep old sign
sub.l %d0,%d1 # add scale factor
or.w %d2,%d1 # concat old sign,new exp
mov.w %d1,FP_SCR0_EX(%a6) # insert new exponent
mov.l (%sp)+,%d2 # restore d2
fmovm.x FP_SCR0(%a6),&0x80 # return result in fp0
rts
tbl_fdiv_ovfl2:
long 0x7fff
long 0x407f
long 0x43ff
fdiv_unfl:
bset &unfl_bit,FPSR_EXCEPT(%a6) # set unfl exc bit
fmovm.x FP_SCR1(%a6),&0x80 # load dst op
fmov.l &rz_mode*0x10,%fpcr # set FPCR
fmov.l &0x0,%fpsr # clear FPSR
fdiv.x FP_SCR0(%a6),%fp0 # execute divide
fmov.l %fpsr,%d1 # save status
fmov.l &0x0,%fpcr # clear FPCR
or.l %d1,USER_FPSR(%a6) # save INEX2,N
mov.b FPCR_ENABLE(%a6),%d1
andi.b &0x0b,%d1 # is UNFL or INEX enabled?
bne.b fdiv_unfl_ena # yes
fdiv_unfl_dis:
fmovm.x &0x80,FP_SCR0(%a6) # store out result
lea FP_SCR0(%a6),%a0 # pass: result addr
mov.l L_SCR3(%a6),%d1 # pass: rnd prec,mode
bsr.l unf_res # calculate default result
or.b %d0,FPSR_CC(%a6) # 'Z' may have been set
fmovm.x FP_SCR0(%a6),&0x80 # return default result in fp0
rts
#
# UNFL is enabled.
#
fdiv_unfl_ena:
fmovm.x FP_SCR1(%a6),&0x40 # load dst op
mov.l L_SCR3(%a6),%d1
andi.b &0xc0,%d1 # is precision extended?
bne.b fdiv_unfl_ena_sd # no, sgl or dbl
fmovm.x &0x40,FP_SCR0(%a6) # save result to stack
mov.l %d2,-(%sp) # save d2
mov.w FP_SCR0_EX(%a6),%d1 # fetch {sgn,exp}
mov.l %d1,%d2 # make a copy
andi.l &0x7fff,%d1 # strip sign
andi.w &0x8000,%d2 # keep old sign
sub.l %d0,%d1 # add scale factoer
addi.l &0x6000,%d1 # add bias
andi.w &0x7fff,%d1
or.w %d2,%d1 # concat old sign,new exp
mov.w %d1,FP_SCR0_EX(%a6) # insert new exp
mov.l (%sp)+,%d2 # restore d2
fmovm.x FP_SCR0(%a6),&0x40 # return EXOP in fp1
bra.w fdiv_unfl_dis
fdiv_unfl_ena_sd:
mov.l L_SCR3(%a6),%d1
andi.b &0x30,%d1 # use only rnd mode
fmov.l %d1,%fpcr # set FPCR
bra.b fdiv_unfl_ena_cont
#
# the divide operation MAY underflow:
#
fdiv_may_unfl:
fmovm.x FP_SCR1(%a6),&0x80 # load dst op
fmov.l L_SCR3(%a6),%fpcr # set FPCR
fmov.l &0x0,%fpsr # clear FPSR
fdiv.x FP_SCR0(%a6),%fp0 # execute divide
fmov.l %fpsr,%d1 # save status
fmov.l &0x0,%fpcr # clear FPCR
or.l %d1,USER_FPSR(%a6) # save INEX2,N
fabs.x %fp0,%fp1 # make a copy of result
fcmp.b %fp1,&0x1 # is |result| > 1.b?
fbgt.w fdiv_normal_exit # no; no underflow occurred
fblt.w fdiv_unfl # yes; underflow occurred
#
# we still don't know if underflow occurred. result is ~ equal to 1. but,
# we don't know if the result was an underflow that rounded up to a 1
# or a normalized number that rounded down to a 1. so, redo the entire
# operation using RZ as the rounding mode to see what the pre-rounded
# result is. this case should be relatively rare.
#
fmovm.x FP_SCR1(%a6),&0x40 # load dst op into fp1
#
# Divide: inputs are not both normalized; what are they?
#
fdiv_not_norm:
mov.w (tbl_fdiv_op.b,%pc,%d1.w*2),%d1
jmp (tbl_fdiv_op.b,%pc,%d1.w*1)
swbeg &48
tbl_fdiv_op:
short fdiv_norm - tbl_fdiv_op # NORM / NORM
short fdiv_inf_load - tbl_fdiv_op # NORM / ZERO
short fdiv_zero_load - tbl_fdiv_op # NORM / INF
short fdiv_res_qnan - tbl_fdiv_op # NORM / QNAN
short fdiv_norm - tbl_fdiv_op # NORM / DENORM
short fdiv_res_snan - tbl_fdiv_op # NORM / SNAN
short tbl_fdiv_op - tbl_fdiv_op #
short tbl_fdiv_op - tbl_fdiv_op #
short fdiv_zero_load - tbl_fdiv_op # ZERO / NORM
short fdiv_res_operr - tbl_fdiv_op # ZERO / ZERO
short fdiv_zero_load - tbl_fdiv_op # ZERO / INF
short fdiv_res_qnan - tbl_fdiv_op # ZERO / QNAN
short fdiv_zero_load - tbl_fdiv_op # ZERO / DENORM
short fdiv_res_snan - tbl_fdiv_op # ZERO / SNAN
short tbl_fdiv_op - tbl_fdiv_op #
short tbl_fdiv_op - tbl_fdiv_op #
short fdiv_inf_dst - tbl_fdiv_op # INF / NORM
short fdiv_inf_dst - tbl_fdiv_op # INF / ZERO
short fdiv_res_operr - tbl_fdiv_op # INF / INF
short fdiv_res_qnan - tbl_fdiv_op # INF / QNAN
short fdiv_inf_dst - tbl_fdiv_op # INF / DENORM
short fdiv_res_snan - tbl_fdiv_op # INF / SNAN
short tbl_fdiv_op - tbl_fdiv_op #
short tbl_fdiv_op - tbl_fdiv_op #
short fdiv_res_qnan - tbl_fdiv_op # QNAN / NORM
short fdiv_res_qnan - tbl_fdiv_op # QNAN / ZERO
short fdiv_res_qnan - tbl_fdiv_op # QNAN / INF
short fdiv_res_qnan - tbl_fdiv_op # QNAN / QNAN
short fdiv_res_qnan - tbl_fdiv_op # QNAN / DENORM
short fdiv_res_snan - tbl_fdiv_op # QNAN / SNAN
short tbl_fdiv_op - tbl_fdiv_op #
short tbl_fdiv_op - tbl_fdiv_op #
short fdiv_norm - tbl_fdiv_op # DENORM / NORM
short fdiv_inf_load - tbl_fdiv_op # DENORM / ZERO
short fdiv_zero_load - tbl_fdiv_op # DENORM / INF
short fdiv_res_qnan - tbl_fdiv_op # DENORM / QNAN
short fdiv_norm - tbl_fdiv_op # DENORM / DENORM
short fdiv_res_snan - tbl_fdiv_op # DENORM / SNAN
short tbl_fdiv_op - tbl_fdiv_op #
short tbl_fdiv_op - tbl_fdiv_op #
short fdiv_res_snan - tbl_fdiv_op # SNAN / NORM
short fdiv_res_snan - tbl_fdiv_op # SNAN / ZERO
short fdiv_res_snan - tbl_fdiv_op # SNAN / INF
short fdiv_res_snan - tbl_fdiv_op # SNAN / QNAN
short fdiv_res_snan - tbl_fdiv_op # SNAN / DENORM
short fdiv_res_snan - tbl_fdiv_op # SNAN / SNAN
short tbl_fdiv_op - tbl_fdiv_op #
short tbl_fdiv_op - tbl_fdiv_op #
global fdiv_zero_load # global for fsgldiv
fdiv_zero_load:
mov.b SRC_EX(%a0),%d0 # result sign is exclusive
mov.b DST_EX(%a1),%d1 # or of input signs.
eor.b %d0,%d1
bpl.b fdiv_zero_load_p # result is positive
fmov.s &0x80000000,%fp0 # load a -ZERO
mov.b &z_bmask+neg_bmask,FPSR_CC(%a6) # set Z/N
rts
fdiv_zero_load_p:
fmov.s &0x00000000,%fp0 # load a +ZERO
mov.b &z_bmask,FPSR_CC(%a6) # set Z
rts
#
# The destination was In Range and the source was a ZERO. The result,
# therefore, is an INF w/ the proper sign.
# So, determine the sign and return a new INF (w/ the j-bit cleared).
#
global fdiv_inf_load # global for fsgldiv
fdiv_inf_load:
ori.w &dz_mask+adz_mask,2+USER_FPSR(%a6) # no; set DZ/ADZ
mov.b SRC_EX(%a0),%d0 # load both signs
mov.b DST_EX(%a1),%d1
eor.b %d0,%d1
bpl.b fdiv_inf_load_p # result is positive
fmov.s &0xff800000,%fp0 # make result -INF
mov.b &inf_bmask+neg_bmask,FPSR_CC(%a6) # set INF/N
rts
fdiv_inf_load_p:
fmov.s &0x7f800000,%fp0 # make result +INF
mov.b &inf_bmask,FPSR_CC(%a6) # set INF
rts
#
# The destination was an INF w/ an In Range or ZERO source, the result is
# an INF w/ the proper sign.
# The 68881/882 returns the destination INF w/ the new sign(if the j-bit of the
# dst INF is set, then then j-bit of the result INF is also set).
#
global fdiv_inf_dst # global for fsgldiv
fdiv_inf_dst:
mov.b DST_EX(%a1),%d0 # load both signs
mov.b SRC_EX(%a0),%d1
eor.b %d0,%d1
bpl.b fdiv_inf_dst_p # result is positive
fmovm.x DST(%a1),&0x80 # return result in fp0
fabs.x %fp0 # clear sign bit
fneg.x %fp0 # set sign bit
mov.b &inf_bmask+neg_bmask,FPSR_CC(%a6) # set INF/NEG
rts
fdiv_inf_dst_p:
fmovm.x DST(%a1),&0x80 # return result in fp0
fabs.x %fp0 # return positive INF
mov.b &inf_bmask,FPSR_CC(%a6) # set INF
rts
#########################################################################
# XDEF **************************************************************** #
# fneg(): emulates the fneg instruction #
# fsneg(): emulates the fsneg instruction #
# fdneg(): emulates the fdneg instruction #
# #
# XREF **************************************************************** #
# norm() - normalize a denorm to provide EXOP #
# scale_to_zero_src() - scale sgl/dbl source exponent #
# ovf_res() - return default overflow result #
# unf_res() - return default underflow result #
# res_qnan_1op() - return QNAN result #
# res_snan_1op() - return SNAN result #
# #
# INPUT *************************************************************** #
# a0 = pointer to extended precision source operand #
# d0 = rnd prec,mode #
# #
# OUTPUT ************************************************************** #
# fp0 = result #
# fp1 = EXOP (if exception occurred) #
# #
# ALGORITHM *********************************************************** #
# Handle NANs, zeroes, and infinities as special cases. Separate #
# norms/denorms into ext/sgl/dbl precisions. Extended precision can be #
# emulated by simply setting sign bit. Sgl/dbl operands must be scaled #
# and an actual fneg performed to see if overflow/underflow would have #
# occurred. If so, return default underflow/overflow result. Else, #
# scale the result exponent and return result. FPSR gets set based on #
# the result value. #
# #
#########################################################################
global fneg
fneg:
mov.l %d0,L_SCR3(%a6) # store rnd info
mov.b STAG(%a6),%d1
bne.w fneg_not_norm # optimize on non-norm input
#
# NEGATE SIGN : norms and denorms ONLY!
#
fneg_norm:
andi.b &0xc0,%d0 # is precision extended?
bne.w fneg_not_ext # no; go handle sgl or dbl
#
# precision selected is extended. so...we can not get an underflow
# or overflow because of rounding to the correct precision. so...
# skip the scaling and unscaling...
#
mov.l SRC_HI(%a0),FP_SCR0_HI(%a6)
mov.l SRC_LO(%a0),FP_SCR0_LO(%a6)
mov.w SRC_EX(%a0),%d0
eori.w &0x8000,%d0 # negate sign
bpl.b fneg_norm_load # sign is positive
mov.b &neg_bmask,FPSR_CC(%a6) # set 'N' ccode bit
fneg_norm_load:
mov.w %d0,FP_SCR0_EX(%a6)
fmovm.x FP_SCR0(%a6),&0x80 # return result in fp0
rts
#
# for an extended precision DENORM, the UNFL exception bit is set
# the accrued bit is NOT set in this instance(no inexactness!)
#
fneg_denorm:
andi.b &0xc0,%d0 # is precision extended?
bne.b fneg_not_ext # no; go handle sgl or dbl
bset &unfl_bit,FPSR_EXCEPT(%a6) # set unfl exc bit
mov.l SRC_HI(%a0),FP_SCR0_HI(%a6)
mov.l SRC_LO(%a0),FP_SCR0_LO(%a6)
mov.w SRC_EX(%a0),%d0
eori.w &0x8000,%d0 # negate sign
bpl.b fneg_denorm_done # no
mov.b &neg_bmask,FPSR_CC(%a6) # yes, set 'N' ccode bit
fneg_denorm_done:
mov.w %d0,FP_SCR0_EX(%a6)
fmovm.x FP_SCR0(%a6),&0x80 # return default result in fp0
#
# the input is an extended DENORM and underflow is enabled in the FPCR.
# normalize the mantissa and add the bias of 0x6000 to the resulting negative
# exponent and insert back into the operand.
#
fneg_ext_unfl_ena:
lea FP_SCR0(%a6),%a0 # pass: ptr to operand
bsr.l norm # normalize result
neg.w %d0 # new exponent = -(shft val)
addi.w &0x6000,%d0 # add new bias to exponent
mov.w FP_SCR0_EX(%a6),%d1 # fetch old sign,exp
andi.w &0x8000,%d1 # keep old sign
andi.w &0x7fff,%d0 # clear sign position
or.w %d1,%d0 # concat old sign, new exponent
mov.w %d0,FP_SCR0_EX(%a6) # insert new exponent
fmovm.x FP_SCR0(%a6),&0x40 # return EXOP in fp1
rts
#
# operand is either single or double
#
fneg_not_ext:
cmpi.b %d0,&s_mode*0x10 # separate sgl/dbl prec
bne.b fneg_dbl
#
# operand is to be rounded to single precision
#
fneg_sgl:
mov.w SRC_EX(%a0),FP_SCR0_EX(%a6)
mov.l SRC_HI(%a0),FP_SCR0_HI(%a6)
mov.l SRC_LO(%a0),FP_SCR0_LO(%a6)
bsr.l scale_to_zero_src # calculate scale factor
cmpi.l %d0,&0x3fff-0x3f80 # will move in underflow?
bge.w fneg_sd_unfl # yes; go handle underflow
cmpi.l %d0,&0x3fff-0x407e # will move in overflow?
beq.w fneg_sd_may_ovfl # maybe; go check
blt.w fneg_sd_ovfl # yes; go handle overflow
#
# operand will NOT overflow or underflow when moved in to the fp reg file
#
fneg_sd_normal:
fmov.l &0x0,%fpsr # clear FPSR
fmov.l L_SCR3(%a6),%fpcr # set FPCR
fneg.x FP_SCR0(%a6),%fp0 # perform negation
fmov.l %fpsr,%d1 # save FPSR
fmov.l &0x0,%fpcr # clear FPCR
or.l %d1,USER_FPSR(%a6) # save INEX2,N
fneg_sd_normal_exit:
mov.l %d2,-(%sp) # save d2
fmovm.x &0x80,FP_SCR0(%a6) # store out result
mov.w FP_SCR0_EX(%a6),%d1 # load sgn,exp
mov.w %d1,%d2 # make a copy
andi.l &0x7fff,%d1 # strip sign
sub.l %d0,%d1 # add scale factor
andi.w &0x8000,%d2 # keep old sign
or.w %d1,%d2 # concat old sign,new exp
mov.w %d2,FP_SCR0_EX(%a6) # insert new exponent
mov.l (%sp)+,%d2 # restore d2
fmovm.x FP_SCR0(%a6),&0x80 # return result in fp0
rts
#
# operand is to be rounded to double precision
#
fneg_dbl:
mov.w SRC_EX(%a0),FP_SCR0_EX(%a6)
mov.l SRC_HI(%a0),FP_SCR0_HI(%a6)
mov.l SRC_LO(%a0),FP_SCR0_LO(%a6)
bsr.l scale_to_zero_src # calculate scale factor
cmpi.l %d0,&0x3fff-0x3c00 # will move in underflow?
bge.b fneg_sd_unfl # yes; go handle underflow
cmpi.l %d0,&0x3fff-0x43fe # will move in overflow?
beq.w fneg_sd_may_ovfl # maybe; go check
blt.w fneg_sd_ovfl # yes; go handle overflow
bra.w fneg_sd_normal # no; ho handle normalized op
#
# operand WILL underflow when moved in to the fp register file
#
fneg_sd_unfl:
bset &unfl_bit,FPSR_EXCEPT(%a6) # set unfl exc bit
eori.b &0x80,FP_SCR0_EX(%a6) # negate sign
bpl.b fneg_sd_unfl_tst
bset &neg_bit,FPSR_CC(%a6) # set 'N' ccode bit
# if underflow or inexact is enabled, go calculate EXOP first.
fneg_sd_unfl_tst:
mov.b FPCR_ENABLE(%a6),%d1
andi.b &0x0b,%d1 # is UNFL or INEX enabled?
bne.b fneg_sd_unfl_ena # yes
fneg_sd_unfl_dis:
lea FP_SCR0(%a6),%a0 # pass: result addr
mov.l L_SCR3(%a6),%d1 # pass: rnd prec,mode
bsr.l unf_res # calculate default result
or.b %d0,FPSR_CC(%a6) # unf_res may have set 'Z'
fmovm.x FP_SCR0(%a6),&0x80 # return default result in fp0
rts
#
# operand will underflow AND underflow is enabled.
# therefore, we must return the result rounded to extended precision.
#
fneg_sd_unfl_ena:
mov.l FP_SCR0_HI(%a6),FP_SCR1_HI(%a6)
mov.l FP_SCR0_LO(%a6),FP_SCR1_LO(%a6)
mov.w FP_SCR0_EX(%a6),%d1 # load current exponent
mov.l %d2,-(%sp) # save d2
mov.l %d1,%d2 # make a copy
andi.l &0x7fff,%d1 # strip sign
andi.w &0x8000,%d2 # keep old sign
sub.l %d0,%d1 # subtract scale factor
addi.l &0x6000,%d1 # add new bias
andi.w &0x7fff,%d1
or.w %d2,%d1 # concat new sign,new exp
mov.w %d1,FP_SCR1_EX(%a6) # insert new exp
fmovm.x FP_SCR1(%a6),&0x40 # return EXOP in fp1
mov.l (%sp)+,%d2 # restore d2
bra.b fneg_sd_unfl_dis
#
# operand WILL overflow.
#
fneg_sd_ovfl:
fmov.l &0x0,%fpsr # clear FPSR
fmov.l L_SCR3(%a6),%fpcr # set FPCR
fneg.x FP_SCR0(%a6),%fp0 # perform negation
fmov.l &0x0,%fpcr # clear FPCR
fmov.l %fpsr,%d1 # save FPSR
or.l %d1,USER_FPSR(%a6) # save INEX2,N
fneg_sd_ovfl_tst:
or.l &ovfl_inx_mask,USER_FPSR(%a6) # set ovfl/aovfl/ainex
mov.b FPCR_ENABLE(%a6),%d1
andi.b &0x13,%d1 # is OVFL or INEX enabled?
bne.b fneg_sd_ovfl_ena # yes
#
# OVFL is not enabled; therefore, we must create the default result by
# calling ovf_res().
#
fneg_sd_ovfl_dis:
btst &neg_bit,FPSR_CC(%a6) # is result negative?
sne %d1 # set sign param accordingly
mov.l L_SCR3(%a6),%d0 # pass: prec,mode
bsr.l ovf_res # calculate default result
or.b %d0,FPSR_CC(%a6) # set INF,N if applicable
fmovm.x (%a0),&0x80 # return default result in fp0
rts
#
# OVFL is enabled.
# the INEX2 bit has already been updated by the round to the correct precision.
# now, round to extended(and don't alter the FPSR).
#
fneg_sd_ovfl_ena:
mov.l %d2,-(%sp) # save d2
mov.w FP_SCR0_EX(%a6),%d1 # fetch {sgn,exp}
mov.l %d1,%d2 # make a copy
andi.l &0x7fff,%d1 # strip sign
andi.w &0x8000,%d2 # keep old sign
sub.l %d0,%d1 # add scale factor
subi.l &0x6000,%d1 # subtract bias
andi.w &0x7fff,%d1
or.w %d2,%d1 # concat sign,exp
mov.w %d1,FP_SCR0_EX(%a6) # insert new exponent
fmovm.x FP_SCR0(%a6),&0x40 # return EXOP in fp1
mov.l (%sp)+,%d2 # restore d2
bra.b fneg_sd_ovfl_dis
#
# the move in MAY underflow. so...
#
fneg_sd_may_ovfl:
fmov.l &0x0,%fpsr # clear FPSR
fmov.l L_SCR3(%a6),%fpcr # set FPCR
fneg.x FP_SCR0(%a6),%fp0 # perform negation
fmov.l %fpsr,%d1 # save status
fmov.l &0x0,%fpcr # clear FPCR
or.l %d1,USER_FPSR(%a6) # save INEX2,N
fabs.x %fp0,%fp1 # make a copy of result
fcmp.b %fp1,&0x2 # is |result| >= 2.b?
fbge.w fneg_sd_ovfl_tst # yes; overflow has occurred
# no, it didn't overflow; we have correct result
bra.w fneg_sd_normal_exit
#
# input is not normalized; what is it?
#
fneg_not_norm:
cmpi.b %d1,&DENORM # weed out DENORM
beq.w fneg_denorm
cmpi.b %d1,&SNAN # weed out SNAN
beq.l res_snan_1op
cmpi.b %d1,&QNAN # weed out QNAN
beq.l res_qnan_1op
#
# do the fneg; at this point, only possible ops are ZERO and INF.
# use fneg to determine ccodes.
# prec:mode should be zero at this point but it won't affect answer anyways.
#
fneg.x SRC_EX(%a0),%fp0 # do fneg
fmov.l %fpsr,%d0
rol.l &0x8,%d0 # put ccodes in lo byte
mov.b %d0,FPSR_CC(%a6) # insert correct ccodes
rts
#########################################################################
# XDEF **************************************************************** #
# ftst(): emulates the ftest instruction #
# #
# XREF **************************************************************** #
# res{s,q}nan_1op() - set NAN result for monadic instruction #
# #
# INPUT *************************************************************** #
# a0 = pointer to extended precision source operand #
# #
# OUTPUT ************************************************************** #
# none #
# #
# ALGORITHM *********************************************************** #
# Check the source operand tag (STAG) and set the FPCR according #
# to the operand type and sign. #
# #
#########################################################################
global ftst
ftst:
mov.b STAG(%a6),%d1
bne.b ftst_not_norm # optimize on non-norm input
#
# Norm:
#
ftst_norm:
tst.b SRC_EX(%a0) # is operand negative?
bmi.b ftst_norm_m # yes
rts
ftst_norm_m:
mov.b &neg_bmask,FPSR_CC(%a6) # set 'N' ccode bit
rts
#
# input is not normalized; what is it?
#
ftst_not_norm:
cmpi.b %d1,&ZERO # weed out ZERO
beq.b ftst_zero
cmpi.b %d1,&INF # weed out INF
beq.b ftst_inf
cmpi.b %d1,&SNAN # weed out SNAN
beq.l res_snan_1op
cmpi.b %d1,&QNAN # weed out QNAN
beq.l res_qnan_1op
#
# Denorm:
#
ftst_denorm:
tst.b SRC_EX(%a0) # is operand negative?
bmi.b ftst_denorm_m # yes
rts
ftst_denorm_m:
mov.b &neg_bmask,FPSR_CC(%a6) # set 'N' ccode bit
rts
#
# Infinity:
#
ftst_inf:
tst.b SRC_EX(%a0) # is operand negative?
bmi.b ftst_inf_m # yes
ftst_inf_p:
mov.b &inf_bmask,FPSR_CC(%a6) # set 'I' ccode bit
rts
ftst_inf_m:
mov.b &inf_bmask+neg_bmask,FPSR_CC(%a6) # set 'I','N' ccode bits
rts
#
# Zero:
#
ftst_zero:
tst.b SRC_EX(%a0) # is operand negative?
bmi.b ftst_zero_m # yes
ftst_zero_p:
mov.b &z_bmask,FPSR_CC(%a6) # set 'N' ccode bit
rts
ftst_zero_m:
mov.b &z_bmask+neg_bmask,FPSR_CC(%a6) # set 'Z','N' ccode bits
rts
#########################################################################
# XDEF **************************************************************** #
# fint(): emulates the fint instruction #
# #
# XREF **************************************************************** #
# res_{s,q}nan_1op() - set NAN result for monadic operation #
# #
# INPUT *************************************************************** #
# a0 = pointer to extended precision source operand #
# d0 = round precision/mode #
# #
# OUTPUT ************************************************************** #
# fp0 = result #
# #
# ALGORITHM *********************************************************** #
# Separate according to operand type. Unnorms don't pass through #
# here. For norms, load the rounding mode/prec, execute a "fint", then #
# store the resulting FPSR bits. #
# For denorms, force the j-bit to a one and do the same as for #
# norms. Denorms are so low that the answer will either be a zero or a #
# one. #
# For zeroes/infs/NANs, return the same while setting the FPSR #
# as appropriate. #
# #
#########################################################################
global fint
fint:
mov.b STAG(%a6),%d1
bne.b fint_not_norm # optimize on non-norm input
fmov.l %d0,%fpcr # set FPCR
fmov.l &0x0,%fpsr # clear FPSR
fint.x SRC(%a0),%fp0 # execute fint
fmov.l &0x0,%fpcr # clear FPCR
fmov.l %fpsr,%d0 # save FPSR
or.l %d0,USER_FPSR(%a6) # set exception bits
rts
#
# input is not normalized; what is it?
#
fint_not_norm:
cmpi.b %d1,&ZERO # weed out ZERO
beq.b fint_zero
cmpi.b %d1,&INF # weed out INF
beq.b fint_inf
cmpi.b %d1,&DENORM # weed out DENORM
beq.b fint_denorm
cmpi.b %d1,&SNAN # weed out SNAN
beq.l res_snan_1op
bra.l res_qnan_1op # weed out QNAN
#
# Denorm:
#
# for DENORMs, the result will be either (+/-)ZERO or (+/-)1.
# also, the INEX2 and AINEX exception bits will be set.
# so, we could either set these manually or force the DENORM
# to a very small NORM and ship it to the NORM routine.
# I do the latter.
#
fint_denorm:
mov.w SRC_EX(%a0),FP_SCR0_EX(%a6) # copy sign, zero exp
mov.b &0x80,FP_SCR0_HI(%a6) # force DENORM ==> small NORM
lea FP_SCR0(%a6),%a0
bra.b fint_norm
#
# Zero:
#
fint_zero:
tst.b SRC_EX(%a0) # is ZERO negative?
bmi.b fint_zero_m # yes
fint_zero_p:
fmov.s &0x00000000,%fp0 # return +ZERO in fp0
mov.b &z_bmask,FPSR_CC(%a6) # set 'Z' ccode bit
rts
fint_zero_m:
fmov.s &0x80000000,%fp0 # return -ZERO in fp0
mov.b &z_bmask+neg_bmask,FPSR_CC(%a6) # set 'Z','N' ccode bits
rts
#
# Infinity:
#
fint_inf:
fmovm.x SRC(%a0),&0x80 # return result in fp0
tst.b SRC_EX(%a0) # is INF negative?
bmi.b fint_inf_m # yes
fint_inf_p:
mov.b &inf_bmask,FPSR_CC(%a6) # set 'I' ccode bit
rts
fint_inf_m:
mov.b &inf_bmask+neg_bmask,FPSR_CC(%a6) # set 'N','I' ccode bits
rts
#########################################################################
# XDEF **************************************************************** #
# fintrz(): emulates the fintrz instruction #
# #
# XREF **************************************************************** #
# res_{s,q}nan_1op() - set NAN result for monadic operation #
# #
# INPUT *************************************************************** #
# a0 = pointer to extended precision source operand #
# d0 = round precision/mode #
# #
# OUTPUT ************************************************************** #
# fp0 = result #
# #
# ALGORITHM *********************************************************** #
# Separate according to operand type. Unnorms don't pass through #
# here. For norms, load the rounding mode/prec, execute a "fintrz", #
# then store the resulting FPSR bits. #
# For denorms, force the j-bit to a one and do the same as for #
# norms. Denorms are so low that the answer will either be a zero or a #
# one. #
# For zeroes/infs/NANs, return the same while setting the FPSR #
# as appropriate. #
# #
#########################################################################
global fintrz
fintrz:
mov.b STAG(%a6),%d1
bne.b fintrz_not_norm # optimize on non-norm input
fmov.l %fpsr,%d0 # save FPSR
or.l %d0,USER_FPSR(%a6) # set exception bits
rts
#
# input is not normalized; what is it?
#
fintrz_not_norm:
cmpi.b %d1,&ZERO # weed out ZERO
beq.b fintrz_zero
cmpi.b %d1,&INF # weed out INF
beq.b fintrz_inf
cmpi.b %d1,&DENORM # weed out DENORM
beq.b fintrz_denorm
cmpi.b %d1,&SNAN # weed out SNAN
beq.l res_snan_1op
bra.l res_qnan_1op # weed out QNAN
#
# Denorm:
#
# for DENORMs, the result will be (+/-)ZERO.
# also, the INEX2 and AINEX exception bits will be set.
# so, we could either set these manually or force the DENORM
# to a very small NORM and ship it to the NORM routine.
# I do the latter.
#
fintrz_denorm:
mov.w SRC_EX(%a0),FP_SCR0_EX(%a6) # copy sign, zero exp
mov.b &0x80,FP_SCR0_HI(%a6) # force DENORM ==> small NORM
lea FP_SCR0(%a6),%a0
bra.b fintrz_norm
#
# Zero:
#
fintrz_zero:
tst.b SRC_EX(%a0) # is ZERO negative?
bmi.b fintrz_zero_m # yes
fintrz_zero_p:
fmov.s &0x00000000,%fp0 # return +ZERO in fp0
mov.b &z_bmask,FPSR_CC(%a6) # set 'Z' ccode bit
rts
fintrz_zero_m:
fmov.s &0x80000000,%fp0 # return -ZERO in fp0
mov.b &z_bmask+neg_bmask,FPSR_CC(%a6) # set 'Z','N' ccode bits
rts
#
# Infinity:
#
fintrz_inf:
fmovm.x SRC(%a0),&0x80 # return result in fp0
tst.b SRC_EX(%a0) # is INF negative?
bmi.b fintrz_inf_m # yes
fintrz_inf_p:
mov.b &inf_bmask,FPSR_CC(%a6) # set 'I' ccode bit
rts
fintrz_inf_m:
mov.b &inf_bmask+neg_bmask,FPSR_CC(%a6) # set 'N','I' ccode bits
rts
#########################################################################
# XDEF **************************************************************** #
# fabs(): emulates the fabs instruction #
# fsabs(): emulates the fsabs instruction #
# fdabs(): emulates the fdabs instruction #
# #
# XREF **************************************************************** #
# norm() - normalize denorm mantissa to provide EXOP #
# scale_to_zero_src() - make exponent. = 0; get scale factor #
# unf_res() - calculate underflow result #
# ovf_res() - calculate overflow result #
# res_{s,q}nan_1op() - set NAN result for monadic operation #
# #
# INPUT *************************************************************** #
# a0 = pointer to extended precision source operand #
# d0 = rnd precision/mode #
# #
# OUTPUT ************************************************************** #
# fp0 = result #
# fp1 = EXOP (if exception occurred) #
# #
# ALGORITHM *********************************************************** #
# Handle NANs, infinities, and zeroes as special cases. Divide #
# norms into extended, single, and double precision. #
# Simply clear sign for extended precision norm. Ext prec denorm #
# gets an EXOP created for it since it's an underflow. #
# Double and single precision can overflow and underflow. First, #
# scale the operand such that the exponent is zero. Perform an "fabs" #
# using the correct rnd mode/prec. Check to see if the original #
# exponent would take an exception. If so, use unf_res() or ovf_res() #
# to calculate the default result. Also, create the EXOP for the #
# exceptional case. If no exception should occur, insert the correct #
# result exponent and return. #
# Unnorms don't pass through here. #
# #
#########################################################################
global fabs
fabs:
mov.l %d0,L_SCR3(%a6) # store rnd info
mov.b STAG(%a6),%d1
bne.w fabs_not_norm # optimize on non-norm input
#
# ABSOLUTE VALUE: norms and denorms ONLY!
#
fabs_norm:
andi.b &0xc0,%d0 # is precision extended?
bne.b fabs_not_ext # no; go handle sgl or dbl
#
# precision selected is extended. so...we can not get an underflow
# or overflow because of rounding to the correct precision. so...
# skip the scaling and unscaling...
#
mov.l SRC_HI(%a0),FP_SCR0_HI(%a6)
mov.l SRC_LO(%a0),FP_SCR0_LO(%a6)
mov.w SRC_EX(%a0),%d1
bclr &15,%d1 # force absolute value
mov.w %d1,FP_SCR0_EX(%a6) # insert exponent
fmovm.x FP_SCR0(%a6),&0x80 # return result in fp0
rts
#
# for an extended precision DENORM, the UNFL exception bit is set
# the accrued bit is NOT set in this instance(no inexactness!)
#
fabs_denorm:
andi.b &0xc0,%d0 # is precision extended?
bne.b fabs_not_ext # no
bset &unfl_bit,FPSR_EXCEPT(%a6) # set unfl exc bit
fmovm.x FP_SCR0(%a6),&0x80 # return default result in fp0
btst &unfl_bit,FPCR_ENABLE(%a6) # is UNFL enabled?
bne.b fabs_ext_unfl_ena
rts
#
# the input is an extended DENORM and underflow is enabled in the FPCR.
# normalize the mantissa and add the bias of 0x6000 to the resulting negative
# exponent and insert back into the operand.
#
fabs_ext_unfl_ena:
lea FP_SCR0(%a6),%a0 # pass: ptr to operand
bsr.l norm # normalize result
neg.w %d0 # new exponent = -(shft val)
addi.w &0x6000,%d0 # add new bias to exponent
mov.w FP_SCR0_EX(%a6),%d1 # fetch old sign,exp
andi.w &0x8000,%d1 # keep old sign
andi.w &0x7fff,%d0 # clear sign position
or.w %d1,%d0 # concat old sign, new exponent
mov.w %d0,FP_SCR0_EX(%a6) # insert new exponent
fmovm.x FP_SCR0(%a6),&0x40 # return EXOP in fp1
rts
#
# operand is either single or double
#
fabs_not_ext:
cmpi.b %d0,&s_mode*0x10 # separate sgl/dbl prec
bne.b fabs_dbl
#
# operand is to be rounded to single precision
#
fabs_sgl:
mov.w SRC_EX(%a0),FP_SCR0_EX(%a6)
mov.l SRC_HI(%a0),FP_SCR0_HI(%a6)
mov.l SRC_LO(%a0),FP_SCR0_LO(%a6)
bsr.l scale_to_zero_src # calculate scale factor
cmpi.l %d0,&0x3fff-0x3f80 # will move in underflow?
bge.w fabs_sd_unfl # yes; go handle underflow
cmpi.l %d0,&0x3fff-0x407e # will move in overflow?
beq.w fabs_sd_may_ovfl # maybe; go check
blt.w fabs_sd_ovfl # yes; go handle overflow
#
# operand will NOT overflow or underflow when moved in to the fp reg file
#
fabs_sd_normal:
fmov.l &0x0,%fpsr # clear FPSR
fmov.l L_SCR3(%a6),%fpcr # set FPCR
fabs.x FP_SCR0(%a6),%fp0 # perform absolute
fmov.l %fpsr,%d1 # save FPSR
fmov.l &0x0,%fpcr # clear FPCR
or.l %d1,USER_FPSR(%a6) # save INEX2,N
fabs_sd_normal_exit:
mov.l %d2,-(%sp) # save d2
fmovm.x &0x80,FP_SCR0(%a6) # store out result
mov.w FP_SCR0_EX(%a6),%d1 # load sgn,exp
mov.l %d1,%d2 # make a copy
andi.l &0x7fff,%d1 # strip sign
sub.l %d0,%d1 # add scale factor
andi.w &0x8000,%d2 # keep old sign
or.w %d1,%d2 # concat old sign,new exp
mov.w %d2,FP_SCR0_EX(%a6) # insert new exponent
mov.l (%sp)+,%d2 # restore d2
fmovm.x FP_SCR0(%a6),&0x80 # return result in fp0
rts
#
# operand is to be rounded to double precision
#
fabs_dbl:
mov.w SRC_EX(%a0),FP_SCR0_EX(%a6)
mov.l SRC_HI(%a0),FP_SCR0_HI(%a6)
mov.l SRC_LO(%a0),FP_SCR0_LO(%a6)
bsr.l scale_to_zero_src # calculate scale factor
cmpi.l %d0,&0x3fff-0x3c00 # will move in underflow?
bge.b fabs_sd_unfl # yes; go handle underflow
cmpi.l %d0,&0x3fff-0x43fe # will move in overflow?
beq.w fabs_sd_may_ovfl # maybe; go check
blt.w fabs_sd_ovfl # yes; go handle overflow
bra.w fabs_sd_normal # no; ho handle normalized op
#
# operand WILL underflow when moved in to the fp register file
#
fabs_sd_unfl:
bset &unfl_bit,FPSR_EXCEPT(%a6) # set unfl exc bit
bclr &0x7,FP_SCR0_EX(%a6) # force absolute value
# if underflow or inexact is enabled, go calculate EXOP first.
mov.b FPCR_ENABLE(%a6),%d1
andi.b &0x0b,%d1 # is UNFL or INEX enabled?
bne.b fabs_sd_unfl_ena # yes
fabs_sd_unfl_dis:
lea FP_SCR0(%a6),%a0 # pass: result addr
mov.l L_SCR3(%a6),%d1 # pass: rnd prec,mode
bsr.l unf_res # calculate default result
or.b %d0,FPSR_CC(%a6) # set possible 'Z' ccode
fmovm.x FP_SCR0(%a6),&0x80 # return default result in fp0
rts
#
# operand will underflow AND underflow is enabled.
# therefore, we must return the result rounded to extended precision.
#
fabs_sd_unfl_ena:
mov.l FP_SCR0_HI(%a6),FP_SCR1_HI(%a6)
mov.l FP_SCR0_LO(%a6),FP_SCR1_LO(%a6)
mov.w FP_SCR0_EX(%a6),%d1 # load current exponent
mov.l %d2,-(%sp) # save d2
mov.l %d1,%d2 # make a copy
andi.l &0x7fff,%d1 # strip sign
andi.w &0x8000,%d2 # keep old sign
sub.l %d0,%d1 # subtract scale factor
addi.l &0x6000,%d1 # add new bias
andi.w &0x7fff,%d1
or.w %d2,%d1 # concat new sign,new exp
mov.w %d1,FP_SCR1_EX(%a6) # insert new exp
fmovm.x FP_SCR1(%a6),&0x40 # return EXOP in fp1
mov.l (%sp)+,%d2 # restore d2
bra.b fabs_sd_unfl_dis
#
# operand WILL overflow.
#
fabs_sd_ovfl:
fmov.l &0x0,%fpsr # clear FPSR
fmov.l L_SCR3(%a6),%fpcr # set FPCR
fabs.x FP_SCR0(%a6),%fp0 # perform absolute
fmov.l &0x0,%fpcr # clear FPCR
fmov.l %fpsr,%d1 # save FPSR
or.l %d1,USER_FPSR(%a6) # save INEX2,N
fabs_sd_ovfl_tst:
or.l &ovfl_inx_mask,USER_FPSR(%a6) # set ovfl/aovfl/ainex
mov.b FPCR_ENABLE(%a6),%d1
andi.b &0x13,%d1 # is OVFL or INEX enabled?
bne.b fabs_sd_ovfl_ena # yes
#
# OVFL is not enabled; therefore, we must create the default result by
# calling ovf_res().
#
fabs_sd_ovfl_dis:
btst &neg_bit,FPSR_CC(%a6) # is result negative?
sne %d1 # set sign param accordingly
mov.l L_SCR3(%a6),%d0 # pass: prec,mode
bsr.l ovf_res # calculate default result
or.b %d0,FPSR_CC(%a6) # set INF,N if applicable
fmovm.x (%a0),&0x80 # return default result in fp0
rts
#
# OVFL is enabled.
# the INEX2 bit has already been updated by the round to the correct precision.
# now, round to extended(and don't alter the FPSR).
#
fabs_sd_ovfl_ena:
mov.l %d2,-(%sp) # save d2
mov.w FP_SCR0_EX(%a6),%d1 # fetch {sgn,exp}
mov.l %d1,%d2 # make a copy
andi.l &0x7fff,%d1 # strip sign
andi.w &0x8000,%d2 # keep old sign
sub.l %d0,%d1 # add scale factor
subi.l &0x6000,%d1 # subtract bias
andi.w &0x7fff,%d1
or.w %d2,%d1 # concat sign,exp
mov.w %d1,FP_SCR0_EX(%a6) # insert new exponent
fmovm.x FP_SCR0(%a6),&0x40 # return EXOP in fp1
mov.l (%sp)+,%d2 # restore d2
bra.b fabs_sd_ovfl_dis
#
# the move in MAY underflow. so...
#
fabs_sd_may_ovfl:
fmov.l &0x0,%fpsr # clear FPSR
fmov.l L_SCR3(%a6),%fpcr # set FPCR
fabs.x FP_SCR0(%a6),%fp0 # perform absolute
fmov.l %fpsr,%d1 # save status
fmov.l &0x0,%fpcr # clear FPCR
or.l %d1,USER_FPSR(%a6) # save INEX2,N
fabs.x %fp0,%fp1 # make a copy of result
fcmp.b %fp1,&0x2 # is |result| >= 2.b?
fbge.w fabs_sd_ovfl_tst # yes; overflow has occurred
# no, it didn't overflow; we have correct result
bra.w fabs_sd_normal_exit
#
# input is not normalized; what is it?
#
fabs_not_norm:
cmpi.b %d1,&DENORM # weed out DENORM
beq.w fabs_denorm
cmpi.b %d1,&SNAN # weed out SNAN
beq.l res_snan_1op
cmpi.b %d1,&QNAN # weed out QNAN
beq.l res_qnan_1op
fabs.x SRC(%a0),%fp0 # force absolute value
cmpi.b %d1,&INF # weed out INF
beq.b fabs_inf
fabs_zero:
mov.b &z_bmask,FPSR_CC(%a6) # set 'Z' ccode bit
rts
fabs_inf:
mov.b &inf_bmask,FPSR_CC(%a6) # set 'I' ccode bit
rts
#########################################################################
# XDEF **************************************************************** #
# fcmp(): fp compare op routine #
# #
# XREF **************************************************************** #
# res_qnan() - return QNAN result #
# res_snan() - return SNAN result #
# #
# INPUT *************************************************************** #
# a0 = pointer to extended precision source operand #
# a1 = pointer to extended precision destination operand #
# d0 = round prec/mode #
# #
# OUTPUT ************************************************************** #
# None #
# #
# ALGORITHM *********************************************************** #
# Handle NANs and denorms as special cases. For everything else, #
# just use the actual fcmp instruction to produce the correct condition #
# codes. #
# #
#########################################################################
global fcmp
fcmp:
clr.w %d1
mov.b DTAG(%a6),%d1
lsl.b &0x3,%d1
or.b STAG(%a6),%d1
bne.b fcmp_not_norm # optimize on non-norm input
#
# COMPARE FP OPs : NORMs, ZEROs, INFs, and "corrected" DENORMs
#
fcmp_norm:
fmovm.x DST(%a1),&0x80 # load dst op
fcmp.x %fp0,SRC(%a0) # do compare
fmov.l %fpsr,%d0 # save FPSR
rol.l &0x8,%d0 # extract ccode bits
mov.b %d0,FPSR_CC(%a6) # set ccode bits(no exc bits are set)
rts
#
# fcmp: inputs are not both normalized; what are they?
#
fcmp_not_norm:
mov.w (tbl_fcmp_op.b,%pc,%d1.w*2),%d1
jmp (tbl_fcmp_op.b,%pc,%d1.w*1)
swbeg &48
tbl_fcmp_op:
short fcmp_norm - tbl_fcmp_op # NORM - NORM
short fcmp_norm - tbl_fcmp_op # NORM - ZERO
short fcmp_norm - tbl_fcmp_op # NORM - INF
short fcmp_res_qnan - tbl_fcmp_op # NORM - QNAN
short fcmp_nrm_dnrm - tbl_fcmp_op # NORM - DENORM
short fcmp_res_snan - tbl_fcmp_op # NORM - SNAN
short tbl_fcmp_op - tbl_fcmp_op #
short tbl_fcmp_op - tbl_fcmp_op #
short fcmp_norm - tbl_fcmp_op # ZERO - NORM
short fcmp_norm - tbl_fcmp_op # ZERO - ZERO
short fcmp_norm - tbl_fcmp_op # ZERO - INF
short fcmp_res_qnan - tbl_fcmp_op # ZERO - QNAN
short fcmp_dnrm_s - tbl_fcmp_op # ZERO - DENORM
short fcmp_res_snan - tbl_fcmp_op # ZERO - SNAN
short tbl_fcmp_op - tbl_fcmp_op #
short tbl_fcmp_op - tbl_fcmp_op #
short fcmp_norm - tbl_fcmp_op # INF - NORM
short fcmp_norm - tbl_fcmp_op # INF - ZERO
short fcmp_norm - tbl_fcmp_op # INF - INF
short fcmp_res_qnan - tbl_fcmp_op # INF - QNAN
short fcmp_dnrm_s - tbl_fcmp_op # INF - DENORM
short fcmp_res_snan - tbl_fcmp_op # INF - SNAN
short tbl_fcmp_op - tbl_fcmp_op #
short tbl_fcmp_op - tbl_fcmp_op #
short fcmp_res_qnan - tbl_fcmp_op # QNAN - NORM
short fcmp_res_qnan - tbl_fcmp_op # QNAN - ZERO
short fcmp_res_qnan - tbl_fcmp_op # QNAN - INF
short fcmp_res_qnan - tbl_fcmp_op # QNAN - QNAN
short fcmp_res_qnan - tbl_fcmp_op # QNAN - DENORM
short fcmp_res_snan - tbl_fcmp_op # QNAN - SNAN
short tbl_fcmp_op - tbl_fcmp_op #
short tbl_fcmp_op - tbl_fcmp_op #
short fcmp_dnrm_nrm - tbl_fcmp_op # DENORM - NORM
short fcmp_dnrm_d - tbl_fcmp_op # DENORM - ZERO
short fcmp_dnrm_d - tbl_fcmp_op # DENORM - INF
short fcmp_res_qnan - tbl_fcmp_op # DENORM - QNAN
short fcmp_dnrm_sd - tbl_fcmp_op # DENORM - DENORM
short fcmp_res_snan - tbl_fcmp_op # DENORM - SNAN
short tbl_fcmp_op - tbl_fcmp_op #
short tbl_fcmp_op - tbl_fcmp_op #
short fcmp_res_snan - tbl_fcmp_op # SNAN - NORM
short fcmp_res_snan - tbl_fcmp_op # SNAN - ZERO
short fcmp_res_snan - tbl_fcmp_op # SNAN - INF
short fcmp_res_snan - tbl_fcmp_op # SNAN - QNAN
short fcmp_res_snan - tbl_fcmp_op # SNAN - DENORM
short fcmp_res_snan - tbl_fcmp_op # SNAN - SNAN
short tbl_fcmp_op - tbl_fcmp_op #
short tbl_fcmp_op - tbl_fcmp_op #
# unlike all other functions for QNAN and SNAN, fcmp does NOT set the
# 'N' bit for a negative QNAN or SNAN input so we must squelch it here.
fcmp_res_qnan:
bsr.l res_qnan
andi.b &0xf7,FPSR_CC(%a6)
rts
fcmp_res_snan:
bsr.l res_snan
andi.b &0xf7,FPSR_CC(%a6)
rts
#
# DENORMs are a little more difficult.
# If you have a 2 DENORMs, then you can just force the j-bit to a one
# and use the fcmp_norm routine.
# If you have a DENORM and an INF or ZERO, just force the DENORM's j-bit to a one
# and use the fcmp_norm routine.
# If you have a DENORM and a NORM with opposite signs, then use fcmp_norm, also.
# But with a DENORM and a NORM of the same sign, the neg bit is set if the
# (1) signs are (+) and the DENORM is the dst or
# (2) signs are (-) and the DENORM is the src
#
fcmp_dnrm_s:
mov.w SRC_EX(%a0),FP_SCR0_EX(%a6)
mov.l SRC_HI(%a0),%d0
bset &31,%d0 # DENORM src; make into small norm
mov.l %d0,FP_SCR0_HI(%a6)
mov.l SRC_LO(%a0),FP_SCR0_LO(%a6)
lea FP_SCR0(%a6),%a0
bra.w fcmp_norm
fcmp_dnrm_d:
mov.l DST_EX(%a1),FP_SCR0_EX(%a6)
mov.l DST_HI(%a1),%d0
bset &31,%d0 # DENORM src; make into small norm
mov.l %d0,FP_SCR0_HI(%a6)
mov.l DST_LO(%a1),FP_SCR0_LO(%a6)
lea FP_SCR0(%a6),%a1
bra.w fcmp_norm
fcmp_dnrm_sd:
mov.w DST_EX(%a1),FP_SCR1_EX(%a6)
mov.w SRC_EX(%a0),FP_SCR0_EX(%a6)
mov.l DST_HI(%a1),%d0
bset &31,%d0 # DENORM dst; make into small norm
mov.l %d0,FP_SCR1_HI(%a6)
mov.l SRC_HI(%a0),%d0
bset &31,%d0 # DENORM dst; make into small norm
mov.l %d0,FP_SCR0_HI(%a6)
mov.l DST_LO(%a1),FP_SCR1_LO(%a6)
mov.l SRC_LO(%a0),FP_SCR0_LO(%a6)
lea FP_SCR1(%a6),%a1
lea FP_SCR0(%a6),%a0
bra.w fcmp_norm
fcmp_nrm_dnrm:
mov.b SRC_EX(%a0),%d0 # determine if like signs
mov.b DST_EX(%a1),%d1
eor.b %d0,%d1
bmi.w fcmp_dnrm_s
# signs are the same, so must determine the answer ourselves.
tst.b %d0 # is src op negative?
bmi.b fcmp_nrm_dnrm_m # yes
rts
fcmp_nrm_dnrm_m:
mov.b &neg_bmask,FPSR_CC(%a6) # set 'Z' ccode bit
rts
fcmp_dnrm_nrm:
mov.b SRC_EX(%a0),%d0 # determine if like signs
mov.b DST_EX(%a1),%d1
eor.b %d0,%d1
bmi.w fcmp_dnrm_d
# signs are the same, so must determine the answer ourselves.
tst.b %d0 # is src op negative?
bpl.b fcmp_dnrm_nrm_m # no
rts
fcmp_dnrm_nrm_m:
mov.b &neg_bmask,FPSR_CC(%a6) # set 'Z' ccode bit
rts
#########################################################################
# XDEF **************************************************************** #
# fsglmul(): emulates the fsglmul instruction #
# #
# XREF **************************************************************** #
# scale_to_zero_src() - scale src exponent to zero #
# scale_to_zero_dst() - scale dst exponent to zero #
# unf_res4() - return default underflow result for sglop #
# ovf_res() - return default overflow result #
# res_qnan() - return QNAN result #
# res_snan() - return SNAN result #
# #
# INPUT *************************************************************** #
# a0 = pointer to extended precision source operand #
# a1 = pointer to extended precision destination operand #
# d0 rnd prec,mode #
# #
# OUTPUT ************************************************************** #
# fp0 = result #
# fp1 = EXOP (if exception occurred) #
# #
# ALGORITHM *********************************************************** #
# Handle NANs, infinities, and zeroes as special cases. Divide #
# norms/denorms into ext/sgl/dbl precision. #
# For norms/denorms, scale the exponents such that a multiply #
# instruction won't cause an exception. Use the regular fsglmul to #
# compute a result. Check if the regular operands would have taken #
# an exception. If so, return the default overflow/underflow result #
# and return the EXOP if exceptions are enabled. Else, scale the #
# result operand to the proper exponent. #
# #
#########################################################################
global fsglmul
fsglmul:
mov.l %d0,L_SCR3(%a6) # store rnd info
fmov.l %fpsr,%d1 # save status
fmov.l &0x0,%fpcr # clear FPCR
or.l %d1,USER_FPSR(%a6) # save INEX2,N
mov.b FPCR_ENABLE(%a6),%d1
andi.b &0x0b,%d1 # is UNFL or INEX enabled?
bne.b fsglmul_unfl_ena # yes
fsglmul_unfl_dis:
fmovm.x &0x80,FP_SCR0(%a6) # store out result
lea FP_SCR0(%a6),%a0 # pass: result addr
mov.l L_SCR3(%a6),%d1 # pass: rnd prec,mode
bsr.l unf_res4 # calculate default result
or.b %d0,FPSR_CC(%a6) # 'Z' bit may have been set
fmovm.x FP_SCR0(%a6),&0x80 # return default result in fp0
rts
#
# UNFL is enabled.
#
fsglmul_unfl_ena:
fmovm.x FP_SCR1(%a6),&0x40 # load dst op
fmov.l L_SCR3(%a6),%fpcr # set FPCR
fmov.l &0x0,%fpsr # clear FPSR
fmov.l %fpsr,%d1 # save status
fmov.l &0x0,%fpcr # clear FPCR
or.l %d1,USER_FPSR(%a6) # save INEX2,N
fabs.x %fp0,%fp1 # make a copy of result
fcmp.b %fp1,&0x2 # is |result| > 2.b?
fbgt.w fsglmul_normal_exit # no; no underflow occurred
fblt.w fsglmul_unfl # yes; underflow occurred
#
# we still don't know if underflow occurred. result is ~ equal to 2. but,
# we don't know if the result was an underflow that rounded up to a 2 or
# a normalized number that rounded down to a 2. so, redo the entire operation
# using RZ as the rounding mode to see what the pre-rounded result is.
# this case should be relatively rare.
#
fmovm.x FP_SCR1(%a6),&0x40 # load dst op into fp1
#
# Single Precision Multiply: inputs are not both normalized; what are they?
#
fsglmul_not_norm:
mov.w (tbl_fsglmul_op.b,%pc,%d1.w*2),%d1
jmp (tbl_fsglmul_op.b,%pc,%d1.w*1)
swbeg &48
tbl_fsglmul_op:
short fsglmul_norm - tbl_fsglmul_op # NORM x NORM
short fsglmul_zero - tbl_fsglmul_op # NORM x ZERO
short fsglmul_inf_src - tbl_fsglmul_op # NORM x INF
short fsglmul_res_qnan - tbl_fsglmul_op # NORM x QNAN
short fsglmul_norm - tbl_fsglmul_op # NORM x DENORM
short fsglmul_res_snan - tbl_fsglmul_op # NORM x SNAN
short tbl_fsglmul_op - tbl_fsglmul_op #
short tbl_fsglmul_op - tbl_fsglmul_op #
short fsglmul_zero - tbl_fsglmul_op # ZERO x NORM
short fsglmul_zero - tbl_fsglmul_op # ZERO x ZERO
short fsglmul_res_operr - tbl_fsglmul_op # ZERO x INF
short fsglmul_res_qnan - tbl_fsglmul_op # ZERO x QNAN
short fsglmul_zero - tbl_fsglmul_op # ZERO x DENORM
short fsglmul_res_snan - tbl_fsglmul_op # ZERO x SNAN
short tbl_fsglmul_op - tbl_fsglmul_op #
short tbl_fsglmul_op - tbl_fsglmul_op #
short fsglmul_inf_dst - tbl_fsglmul_op # INF x NORM
short fsglmul_res_operr - tbl_fsglmul_op # INF x ZERO
short fsglmul_inf_dst - tbl_fsglmul_op # INF x INF
short fsglmul_res_qnan - tbl_fsglmul_op # INF x QNAN
short fsglmul_inf_dst - tbl_fsglmul_op # INF x DENORM
short fsglmul_res_snan - tbl_fsglmul_op # INF x SNAN
short tbl_fsglmul_op - tbl_fsglmul_op #
short tbl_fsglmul_op - tbl_fsglmul_op #
short fsglmul_res_qnan - tbl_fsglmul_op # QNAN x NORM
short fsglmul_res_qnan - tbl_fsglmul_op # QNAN x ZERO
short fsglmul_res_qnan - tbl_fsglmul_op # QNAN x INF
short fsglmul_res_qnan - tbl_fsglmul_op # QNAN x QNAN
short fsglmul_res_qnan - tbl_fsglmul_op # QNAN x DENORM
short fsglmul_res_snan - tbl_fsglmul_op # QNAN x SNAN
short tbl_fsglmul_op - tbl_fsglmul_op #
short tbl_fsglmul_op - tbl_fsglmul_op #
short fsglmul_norm - tbl_fsglmul_op # NORM x NORM
short fsglmul_zero - tbl_fsglmul_op # NORM x ZERO
short fsglmul_inf_src - tbl_fsglmul_op # NORM x INF
short fsglmul_res_qnan - tbl_fsglmul_op # NORM x QNAN
short fsglmul_norm - tbl_fsglmul_op # NORM x DENORM
short fsglmul_res_snan - tbl_fsglmul_op # NORM x SNAN
short tbl_fsglmul_op - tbl_fsglmul_op #
short tbl_fsglmul_op - tbl_fsglmul_op #
short fsglmul_res_snan - tbl_fsglmul_op # SNAN x NORM
short fsglmul_res_snan - tbl_fsglmul_op # SNAN x ZERO
short fsglmul_res_snan - tbl_fsglmul_op # SNAN x INF
short fsglmul_res_snan - tbl_fsglmul_op # SNAN x QNAN
short fsglmul_res_snan - tbl_fsglmul_op # SNAN x DENORM
short fsglmul_res_snan - tbl_fsglmul_op # SNAN x SNAN
short tbl_fsglmul_op - tbl_fsglmul_op #
short tbl_fsglmul_op - tbl_fsglmul_op #
#########################################################################
# XDEF **************************************************************** #
# fsgldiv(): emulates the fsgldiv instruction #
# #
# XREF **************************************************************** #
# scale_to_zero_src() - scale src exponent to zero #
# scale_to_zero_dst() - scale dst exponent to zero #
# unf_res4() - return default underflow result for sglop #
# ovf_res() - return default overflow result #
# res_qnan() - return QNAN result #
# res_snan() - return SNAN result #
# #
# INPUT *************************************************************** #
# a0 = pointer to extended precision source operand #
# a1 = pointer to extended precision destination operand #
# d0 rnd prec,mode #
# #
# OUTPUT ************************************************************** #
# fp0 = result #
# fp1 = EXOP (if exception occurred) #
# #
# ALGORITHM *********************************************************** #
# Handle NANs, infinities, and zeroes as special cases. Divide #
# norms/denorms into ext/sgl/dbl precision. #
# For norms/denorms, scale the exponents such that a divide #
# instruction won't cause an exception. Use the regular fsgldiv to #
# compute a result. Check if the regular operands would have taken #
# an exception. If so, return the default overflow/underflow result #
# and return the EXOP if exceptions are enabled. Else, scale the #
# result operand to the proper exponent. #
# #
#########################################################################
global fsgldiv
fsgldiv:
mov.l %d0,L_SCR3(%a6) # store rnd info
cmpi.l %d0,&0x3fff-0x0000 # will result underflow?
beq.w fsgldiv_may_unfl # maybe
bgt.w fsgldiv_unfl # yes; go handle underflow
fsgldiv_normal:
fmovm.x FP_SCR1(%a6),&0x80 # load dst op
fmov.l L_SCR3(%a6),%fpcr # save FPCR
fmov.l &0x0,%fpsr # clear FPSR
fsgldiv.x FP_SCR0(%a6),%fp0 # perform sgl divide
fmov.l %fpsr,%d1 # save FPSR
fmov.l &0x0,%fpcr # clear FPCR
or.l %d1,USER_FPSR(%a6) # save INEX2,N
fsgldiv_normal_exit:
fmovm.x &0x80,FP_SCR0(%a6) # store result on stack
mov.l %d2,-(%sp) # save d2
mov.w FP_SCR0_EX(%a6),%d1 # load {sgn,exp}
mov.l %d1,%d2 # make a copy
andi.l &0x7fff,%d1 # strip sign
andi.w &0x8000,%d2 # keep old sign
sub.l %d0,%d1 # add scale factor
or.w %d2,%d1 # concat old sign,new exp
mov.w %d1,FP_SCR0_EX(%a6) # insert new exponent
mov.l (%sp)+,%d2 # restore d2
fmovm.x FP_SCR0(%a6),&0x80 # return result in fp0
rts
fsgldiv_may_ovfl:
fmovm.x FP_SCR1(%a6),&0x80 # load dst op
fmov.l L_SCR3(%a6),%fpcr # set FPCR
fmov.l &0x0,%fpsr # set FPSR
fsgldiv.x FP_SCR0(%a6),%fp0 # execute divide
fmov.l %fpsr,%d1
fmov.l &0x0,%fpcr
or.l %d1,USER_FPSR(%a6) # save INEX,N
fmovm.x &0x01,-(%sp) # save result to stack
mov.w (%sp),%d1 # fetch new exponent
add.l &0xc,%sp # clear result
andi.l &0x7fff,%d1 # strip sign
sub.l %d0,%d1 # add scale factor
cmp.l %d1,&0x7fff # did divide overflow?
blt.b fsgldiv_normal_exit
fsgldiv_ovfl_tst:
or.w &ovfl_inx_mask,2+USER_FPSR(%a6) # set ovfl/aovfl/ainex
mov.b FPCR_ENABLE(%a6),%d1
andi.b &0x13,%d1 # is OVFL or INEX enabled?
bne.b fsgldiv_ovfl_ena # yes
fsgldiv_ovfl_dis:
btst &neg_bit,FPSR_CC(%a6) # is result negative
sne %d1 # set sign param accordingly
mov.l L_SCR3(%a6),%d0 # pass prec:rnd
andi.b &0x30,%d0 # kill precision
bsr.l ovf_res # calculate default result
or.b %d0,FPSR_CC(%a6) # set INF if applicable
fmovm.x (%a0),&0x80 # return default result in fp0
rts
fsgldiv_ovfl_ena:
fmovm.x &0x80,FP_SCR0(%a6) # move result to stack
mov.l %d2,-(%sp) # save d2
mov.w FP_SCR0_EX(%a6),%d1 # fetch {sgn,exp}
mov.l %d1,%d2 # make a copy
andi.l &0x7fff,%d1 # strip sign
andi.w &0x8000,%d2 # keep old sign
sub.l %d0,%d1 # add scale factor
subi.l &0x6000,%d1 # subtract new bias
andi.w &0x7fff,%d1 # clear ms bit
or.w %d2,%d1 # concat old sign,new exp
mov.w %d1,FP_SCR0_EX(%a6) # insert new exponent
mov.l (%sp)+,%d2 # restore d2
fmovm.x FP_SCR0(%a6),&0x40 # return EXOP in fp1
bra.b fsgldiv_ovfl_dis
fsgldiv_unfl:
bset &unfl_bit,FPSR_EXCEPT(%a6) # set unfl exc bit
fmovm.x FP_SCR1(%a6),&0x80 # load dst op
fmov.l &rz_mode*0x10,%fpcr # set FPCR
fmov.l &0x0,%fpsr # clear FPSR
fsgldiv.x FP_SCR0(%a6),%fp0 # execute sgl divide
fmov.l %fpsr,%d1 # save status
fmov.l &0x0,%fpcr # clear FPCR
or.l %d1,USER_FPSR(%a6) # save INEX2,N
mov.b FPCR_ENABLE(%a6),%d1
andi.b &0x0b,%d1 # is UNFL or INEX enabled?
bne.b fsgldiv_unfl_ena # yes
fsgldiv_unfl_dis:
fmovm.x &0x80,FP_SCR0(%a6) # store out result
lea FP_SCR0(%a6),%a0 # pass: result addr
mov.l L_SCR3(%a6),%d1 # pass: rnd prec,mode
bsr.l unf_res4 # calculate default result
or.b %d0,FPSR_CC(%a6) # 'Z' bit may have been set
fmovm.x FP_SCR0(%a6),&0x80 # return default result in fp0
rts
#
# UNFL is enabled.
#
fsgldiv_unfl_ena:
fmovm.x FP_SCR1(%a6),&0x40 # load dst op
fmov.l L_SCR3(%a6),%fpcr # set FPCR
fmov.l &0x0,%fpsr # clear FPSR
fsgldiv.x FP_SCR0(%a6),%fp1 # execute sgl divide
fmov.l &0x0,%fpcr # clear FPCR
fmovm.x &0x40,FP_SCR0(%a6) # save result to stack
mov.l %d2,-(%sp) # save d2
mov.w FP_SCR0_EX(%a6),%d1 # fetch {sgn,exp}
mov.l %d1,%d2 # make a copy
andi.l &0x7fff,%d1 # strip sign
andi.w &0x8000,%d2 # keep old sign
sub.l %d0,%d1 # add scale factor
addi.l &0x6000,%d1 # add bias
andi.w &0x7fff,%d1 # clear top bit
or.w %d2,%d1 # concat old sign, new exp
mov.w %d1,FP_SCR0_EX(%a6) # insert new exponent
mov.l (%sp)+,%d2 # restore d2
fmovm.x FP_SCR0(%a6),&0x40 # return EXOP in fp1
bra.b fsgldiv_unfl_dis
#
# the divide operation MAY underflow:
#
fsgldiv_may_unfl:
fmovm.x FP_SCR1(%a6),&0x80 # load dst op
fmov.l L_SCR3(%a6),%fpcr # set FPCR
fmov.l &0x0,%fpsr # clear FPSR
fsgldiv.x FP_SCR0(%a6),%fp0 # execute sgl divide
fmov.l %fpsr,%d1 # save status
fmov.l &0x0,%fpcr # clear FPCR
or.l %d1,USER_FPSR(%a6) # save INEX2,N
fabs.x %fp0,%fp1 # make a copy of result
fcmp.b %fp1,&0x1 # is |result| > 1.b?
fbgt.w fsgldiv_normal_exit # no; no underflow occurred
fblt.w fsgldiv_unfl # yes; underflow occurred
#
# we still don't know if underflow occurred. result is ~ equal to 1. but,
# we don't know if the result was an underflow that rounded up to a 1
# or a normalized number that rounded down to a 1. so, redo the entire
# operation using RZ as the rounding mode to see what the pre-rounded
# result is. this case should be relatively rare.
#
fmovm.x FP_SCR1(%a6),&0x40 # load dst op into %fp1
#
# Divide: inputs are not both normalized; what are they?
#
fsgldiv_not_norm:
mov.w (tbl_fsgldiv_op.b,%pc,%d1.w*2),%d1
jmp (tbl_fsgldiv_op.b,%pc,%d1.w*1)
swbeg &48
tbl_fsgldiv_op:
short fsgldiv_norm - tbl_fsgldiv_op # NORM / NORM
short fsgldiv_inf_load - tbl_fsgldiv_op # NORM / ZERO
short fsgldiv_zero_load - tbl_fsgldiv_op # NORM / INF
short fsgldiv_res_qnan - tbl_fsgldiv_op # NORM / QNAN
short fsgldiv_norm - tbl_fsgldiv_op # NORM / DENORM
short fsgldiv_res_snan - tbl_fsgldiv_op # NORM / SNAN
short tbl_fsgldiv_op - tbl_fsgldiv_op #
short tbl_fsgldiv_op - tbl_fsgldiv_op #
short fsgldiv_zero_load - tbl_fsgldiv_op # ZERO / NORM
short fsgldiv_res_operr - tbl_fsgldiv_op # ZERO / ZERO
short fsgldiv_zero_load - tbl_fsgldiv_op # ZERO / INF
short fsgldiv_res_qnan - tbl_fsgldiv_op # ZERO / QNAN
short fsgldiv_zero_load - tbl_fsgldiv_op # ZERO / DENORM
short fsgldiv_res_snan - tbl_fsgldiv_op # ZERO / SNAN
short tbl_fsgldiv_op - tbl_fsgldiv_op #
short tbl_fsgldiv_op - tbl_fsgldiv_op #
short fsgldiv_inf_dst - tbl_fsgldiv_op # INF / NORM
short fsgldiv_inf_dst - tbl_fsgldiv_op # INF / ZERO
short fsgldiv_res_operr - tbl_fsgldiv_op # INF / INF
short fsgldiv_res_qnan - tbl_fsgldiv_op # INF / QNAN
short fsgldiv_inf_dst - tbl_fsgldiv_op # INF / DENORM
short fsgldiv_res_snan - tbl_fsgldiv_op # INF / SNAN
short tbl_fsgldiv_op - tbl_fsgldiv_op #
short tbl_fsgldiv_op - tbl_fsgldiv_op #
short fsgldiv_res_qnan - tbl_fsgldiv_op # QNAN / NORM
short fsgldiv_res_qnan - tbl_fsgldiv_op # QNAN / ZERO
short fsgldiv_res_qnan - tbl_fsgldiv_op # QNAN / INF
short fsgldiv_res_qnan - tbl_fsgldiv_op # QNAN / QNAN
short fsgldiv_res_qnan - tbl_fsgldiv_op # QNAN / DENORM
short fsgldiv_res_snan - tbl_fsgldiv_op # QNAN / SNAN
short tbl_fsgldiv_op - tbl_fsgldiv_op #
short tbl_fsgldiv_op - tbl_fsgldiv_op #
short fsgldiv_norm - tbl_fsgldiv_op # DENORM / NORM
short fsgldiv_inf_load - tbl_fsgldiv_op # DENORM / ZERO
short fsgldiv_zero_load - tbl_fsgldiv_op # DENORM / INF
short fsgldiv_res_qnan - tbl_fsgldiv_op # DENORM / QNAN
short fsgldiv_norm - tbl_fsgldiv_op # DENORM / DENORM
short fsgldiv_res_snan - tbl_fsgldiv_op # DENORM / SNAN
short tbl_fsgldiv_op - tbl_fsgldiv_op #
short tbl_fsgldiv_op - tbl_fsgldiv_op #
short fsgldiv_res_snan - tbl_fsgldiv_op # SNAN / NORM
short fsgldiv_res_snan - tbl_fsgldiv_op # SNAN / ZERO
short fsgldiv_res_snan - tbl_fsgldiv_op # SNAN / INF
short fsgldiv_res_snan - tbl_fsgldiv_op # SNAN / QNAN
short fsgldiv_res_snan - tbl_fsgldiv_op # SNAN / DENORM
short fsgldiv_res_snan - tbl_fsgldiv_op # SNAN / SNAN
short tbl_fsgldiv_op - tbl_fsgldiv_op #
short tbl_fsgldiv_op - tbl_fsgldiv_op #
#########################################################################
# XDEF **************************************************************** #
# fadd(): emulates the fadd instruction #
# fsadd(): emulates the fadd instruction #
# fdadd(): emulates the fdadd instruction #
# #
# XREF **************************************************************** #
# addsub_scaler2() - scale the operands so they won't take exc #
# ovf_res() - return default overflow result #
# unf_res() - return default underflow result #
# res_qnan() - set QNAN result #
# res_snan() - set SNAN result #
# res_operr() - set OPERR result #
# scale_to_zero_src() - set src operand exponent equal to zero #
# scale_to_zero_dst() - set dst operand exponent equal to zero #
# #
# INPUT *************************************************************** #
# a0 = pointer to extended precision source operand #
# a1 = pointer to extended precision destination operand #
# #
# OUTPUT ************************************************************** #
# fp0 = result #
# fp1 = EXOP (if exception occurred) #
# #
# ALGORITHM *********************************************************** #
# Handle NANs, infinities, and zeroes as special cases. Divide #
# norms into extended, single, and double precision. #
# Do addition after scaling exponents such that exception won't #
# occur. Then, check result exponent to see if exception would have #
# occurred. If so, return default result and maybe EXOP. Else, insert #
# the correct result exponent and return. Set FPSR bits as appropriate. #
# #
#########################################################################
fadd_unfl:
bset &unfl_bit,FPSR_EXCEPT(%a6) # set unfl exc bit
add.l &0xc,%sp
fmovm.x FP_SCR1(%a6),&0x80 # load dst op
fmov.l &rz_mode*0x10,%fpcr # set FPCR
fmov.l &0x0,%fpsr # clear FPSR
fadd.x FP_SCR0(%a6),%fp0 # execute add
fmov.l &0x0,%fpcr # clear FPCR
fmov.l %fpsr,%d1 # save status
or.l %d1,USER_FPSR(%a6) # save INEX,N
mov.b FPCR_ENABLE(%a6),%d1
andi.b &0x0b,%d1 # is UNFL or INEX enabled?
bne.b fadd_unfl_ena # yes
fadd_unfl_dis:
fmovm.x &0x80,FP_SCR0(%a6) # store out result
lea FP_SCR0(%a6),%a0 # pass: result addr
mov.l L_SCR3(%a6),%d1 # pass: rnd prec,mode
bsr.l unf_res # calculate default result
or.b %d0,FPSR_CC(%a6) # 'Z' bit may have been set
fmovm.x FP_SCR0(%a6),&0x80 # return default result in fp0
mov.l (%sp)+,%d2 # restore d2
rts
fadd_unfl_ena:
fmovm.x FP_SCR1(%a6),&0x40 # load dst op
mov.l L_SCR3(%a6),%d1
andi.b &0xc0,%d1 # is precision extended?
bne.b fadd_unfl_ena_sd # no; sgl or dbl
fmovm.x &0x40,FP_SCR0(%a6) # save result to stack
mov.w FP_SCR0_EX(%a6),%d1 # fetch {sgn,exp}
mov.l %d1,%d2 # make a copy
andi.l &0x7fff,%d1 # strip sign
andi.w &0x8000,%d2 # keep old sign
sub.l %d0,%d1 # add scale factor
addi.l &0x6000,%d1 # add new bias
andi.w &0x7fff,%d1 # clear top bit
or.w %d2,%d1 # concat sign,new exp
mov.w %d1,FP_SCR0_EX(%a6) # insert new exponent
fmovm.x FP_SCR0(%a6),&0x40 # return EXOP in fp1
bra.w fadd_unfl_dis
fadd_unfl_ena_sd:
mov.l L_SCR3(%a6),%d1
andi.b &0x30,%d1 # use only rnd mode
fmov.l %d1,%fpcr # set FPCR
bra.b fadd_unfl_ena_cont
#
# result is equal to the smallest normalized number in the selected precision
# if the precision is extended, this result could not have come from an
# underflow that rounded up.
#
fadd_may_unfl:
mov.l L_SCR3(%a6),%d1
andi.b &0xc0,%d1
beq.w fadd_normal # yes; no underflow occurred
mov.l 0x4(%sp),%d1 # extract hi(man)
cmpi.l %d1,&0x80000000 # is hi(man) = 0x80000000?
bne.w fadd_normal # no; no underflow occurred
tst.l 0x8(%sp) # is lo(man) = 0x0?
bne.w fadd_normal # no; no underflow occurred
btst &inex2_bit,FPSR_EXCEPT(%a6) # is INEX2 set?
beq.w fadd_normal # no; no underflow occurred
#
# ok, so now the result has a exponent equal to the smallest normalized
# exponent for the selected precision. also, the mantissa is equal to
# 0x8000000000000000 and this mantissa is the result of rounding non-zero
# g,r,s.
# now, we must determine whether the pre-rounded result was an underflow
# rounded "up" or a normalized number rounded "down".
# so, we do this be re-executing the add using RZ as the rounding mode and
# seeing if the new result is smaller or equal to the current result.
#
fmovm.x FP_SCR1(%a6),&0x40 # load dst op into fp1
#
# Add: inputs are not both normalized; what are they?
#
fadd_not_norm:
mov.w (tbl_fadd_op.b,%pc,%d1.w*2),%d1
jmp (tbl_fadd_op.b,%pc,%d1.w*1)
swbeg &48
tbl_fadd_op:
short fadd_norm - tbl_fadd_op # NORM + NORM
short fadd_zero_src - tbl_fadd_op # NORM + ZERO
short fadd_inf_src - tbl_fadd_op # NORM + INF
short fadd_res_qnan - tbl_fadd_op # NORM + QNAN
short fadd_norm - tbl_fadd_op # NORM + DENORM
short fadd_res_snan - tbl_fadd_op # NORM + SNAN
short tbl_fadd_op - tbl_fadd_op #
short tbl_fadd_op - tbl_fadd_op #
short fadd_zero_dst - tbl_fadd_op # ZERO + NORM
short fadd_zero_2 - tbl_fadd_op # ZERO + ZERO
short fadd_inf_src - tbl_fadd_op # ZERO + INF
short fadd_res_qnan - tbl_fadd_op # NORM + QNAN
short fadd_zero_dst - tbl_fadd_op # ZERO + DENORM
short fadd_res_snan - tbl_fadd_op # NORM + SNAN
short tbl_fadd_op - tbl_fadd_op #
short tbl_fadd_op - tbl_fadd_op #
short fadd_inf_dst - tbl_fadd_op # INF + NORM
short fadd_inf_dst - tbl_fadd_op # INF + ZERO
short fadd_inf_2 - tbl_fadd_op # INF + INF
short fadd_res_qnan - tbl_fadd_op # NORM + QNAN
short fadd_inf_dst - tbl_fadd_op # INF + DENORM
short fadd_res_snan - tbl_fadd_op # NORM + SNAN
short tbl_fadd_op - tbl_fadd_op #
short tbl_fadd_op - tbl_fadd_op #
short fadd_res_qnan - tbl_fadd_op # QNAN + NORM
short fadd_res_qnan - tbl_fadd_op # QNAN + ZERO
short fadd_res_qnan - tbl_fadd_op # QNAN + INF
short fadd_res_qnan - tbl_fadd_op # QNAN + QNAN
short fadd_res_qnan - tbl_fadd_op # QNAN + DENORM
short fadd_res_snan - tbl_fadd_op # QNAN + SNAN
short tbl_fadd_op - tbl_fadd_op #
short tbl_fadd_op - tbl_fadd_op #
short fadd_norm - tbl_fadd_op # DENORM + NORM
short fadd_zero_src - tbl_fadd_op # DENORM + ZERO
short fadd_inf_src - tbl_fadd_op # DENORM + INF
short fadd_res_qnan - tbl_fadd_op # NORM + QNAN
short fadd_norm - tbl_fadd_op # DENORM + DENORM
short fadd_res_snan - tbl_fadd_op # NORM + SNAN
short tbl_fadd_op - tbl_fadd_op #
short tbl_fadd_op - tbl_fadd_op #
short fadd_res_snan - tbl_fadd_op # SNAN + NORM
short fadd_res_snan - tbl_fadd_op # SNAN + ZERO
short fadd_res_snan - tbl_fadd_op # SNAN + INF
short fadd_res_snan - tbl_fadd_op # SNAN + QNAN
short fadd_res_snan - tbl_fadd_op # SNAN + DENORM
short fadd_res_snan - tbl_fadd_op # SNAN + SNAN
short tbl_fadd_op - tbl_fadd_op #
short tbl_fadd_op - tbl_fadd_op #
#
# both operands are ZEROes
#
fadd_zero_2:
mov.b SRC_EX(%a0),%d0 # are the signs opposite
mov.b DST_EX(%a1),%d1
eor.b %d0,%d1
bmi.w fadd_zero_2_chk_rm # weed out (-ZERO)+(+ZERO)
# the signs are the same. so determine whether they are positive or negative
# and return the appropriately signed zero.
tst.b %d0 # are ZEROes positive or negative?
bmi.b fadd_zero_rm # negative
fmov.s &0x00000000,%fp0 # return +ZERO
mov.b &z_bmask,FPSR_CC(%a6) # set Z
rts
#
# the ZEROes have opposite signs:
# - therefore, we return +ZERO if the rounding modes are RN,RZ, or RP.
# - -ZERO is returned in the case of RM.
#
fadd_zero_2_chk_rm:
mov.b 3+L_SCR3(%a6),%d1
andi.b &0x30,%d1 # extract rnd mode
cmpi.b %d1,&rm_mode*0x10 # is rnd mode == RM?
beq.b fadd_zero_rm # yes
fmov.s &0x00000000,%fp0 # return +ZERO
mov.b &z_bmask,FPSR_CC(%a6) # set Z
rts
#
# one operand is a ZERO and the other is a DENORM or NORM. scale
# the DENORM or NORM and jump to the regular fadd routine.
#
fadd_zero_dst:
mov.w SRC_EX(%a0),FP_SCR0_EX(%a6)
mov.l SRC_HI(%a0),FP_SCR0_HI(%a6)
mov.l SRC_LO(%a0),FP_SCR0_LO(%a6)
bsr.l scale_to_zero_src # scale the operand
clr.w FP_SCR1_EX(%a6)
clr.l FP_SCR1_HI(%a6)
clr.l FP_SCR1_LO(%a6)
bra.w fadd_zero_entry # go execute fadd
#
# both operands are INFs. an OPERR will result if the INFs have
# different signs. else, an INF of the same sign is returned
#
fadd_inf_2:
mov.b SRC_EX(%a0),%d0 # exclusive or the signs
mov.b DST_EX(%a1),%d1
eor.b %d1,%d0
bmi.l res_operr # weed out (-INF)+(+INF)
# ok, so it's not an OPERR. but, we do have to remember to return the
# src INF since that's where the 881/882 gets the j-bit from...
#
# operands are INF and one of {ZERO, INF, DENORM, NORM}
#
fadd_inf_src:
fmovm.x SRC(%a0),&0x80 # return src INF
tst.b SRC_EX(%a0) # is INF positive?
bpl.b fadd_inf_done # yes; we're done
mov.b &neg_bmask+inf_bmask,FPSR_CC(%a6) # set INF/NEG
rts
#
# operands are INF and one of {ZERO, INF, DENORM, NORM}
#
fadd_inf_dst:
fmovm.x DST(%a1),&0x80 # return dst INF
tst.b DST_EX(%a1) # is INF positive?
bpl.b fadd_inf_done # yes; we're done
mov.b &neg_bmask+inf_bmask,FPSR_CC(%a6) # set INF/NEG
rts
fadd_inf_done:
mov.b &inf_bmask,FPSR_CC(%a6) # set INF
rts
#########################################################################
# XDEF **************************************************************** #
# fsub(): emulates the fsub instruction #
# fssub(): emulates the fssub instruction #
# fdsub(): emulates the fdsub instruction #
# #
# XREF **************************************************************** #
# addsub_scaler2() - scale the operands so they won't take exc #
# ovf_res() - return default overflow result #
# unf_res() - return default underflow result #
# res_qnan() - set QNAN result #
# res_snan() - set SNAN result #
# res_operr() - set OPERR result #
# scale_to_zero_src() - set src operand exponent equal to zero #
# scale_to_zero_dst() - set dst operand exponent equal to zero #
# #
# INPUT *************************************************************** #
# a0 = pointer to extended precision source operand #
# a1 = pointer to extended precision destination operand #
# #
# OUTPUT ************************************************************** #
# fp0 = result #
# fp1 = EXOP (if exception occurred) #
# #
# ALGORITHM *********************************************************** #
# Handle NANs, infinities, and zeroes as special cases. Divide #
# norms into extended, single, and double precision. #
# Do subtraction after scaling exponents such that exception won't#
# occur. Then, check result exponent to see if exception would have #
# occurred. If so, return default result and maybe EXOP. Else, insert #
# the correct result exponent and return. Set FPSR bits as appropriate. #
# #
#########################################################################
fsub_unfl:
bset &unfl_bit,FPSR_EXCEPT(%a6) # set unfl exc bit
add.l &0xc,%sp
fmovm.x FP_SCR1(%a6),&0x80 # load dst op
fmov.l &rz_mode*0x10,%fpcr # set FPCR
fmov.l &0x0,%fpsr # clear FPSR
fsub.x FP_SCR0(%a6),%fp0 # execute subtract
fmov.l &0x0,%fpcr # clear FPCR
fmov.l %fpsr,%d1 # save status
or.l %d1,USER_FPSR(%a6)
mov.b FPCR_ENABLE(%a6),%d1
andi.b &0x0b,%d1 # is UNFL or INEX enabled?
bne.b fsub_unfl_ena # yes
fsub_unfl_dis:
fmovm.x &0x80,FP_SCR0(%a6) # store out result
lea FP_SCR0(%a6),%a0 # pass: result addr
mov.l L_SCR3(%a6),%d1 # pass: rnd prec,mode
bsr.l unf_res # calculate default result
or.b %d0,FPSR_CC(%a6) # 'Z' may have been set
fmovm.x FP_SCR0(%a6),&0x80 # return default result in fp0
mov.l (%sp)+,%d2 # restore d2
rts
fsub_unfl_ena:
fmovm.x FP_SCR1(%a6),&0x40
mov.l L_SCR3(%a6),%d1
andi.b &0xc0,%d1 # is precision extended?
bne.b fsub_unfl_ena_sd # no
#
# result is equal to the smallest normalized number in the selected precision
# if the precision is extended, this result could not have come from an
# underflow that rounded up.
#
fsub_may_unfl:
mov.l L_SCR3(%a6),%d1
andi.b &0xc0,%d1 # fetch rnd prec
beq.w fsub_normal # yes; no underflow occurred
mov.l 0x4(%sp),%d1
cmpi.l %d1,&0x80000000 # is hi(man) = 0x80000000?
bne.w fsub_normal # no; no underflow occurred
tst.l 0x8(%sp) # is lo(man) = 0x0?
bne.w fsub_normal # no; no underflow occurred
btst &inex2_bit,FPSR_EXCEPT(%a6) # is INEX2 set?
beq.w fsub_normal # no; no underflow occurred
#
# ok, so now the result has a exponent equal to the smallest normalized
# exponent for the selected precision. also, the mantissa is equal to
# 0x8000000000000000 and this mantissa is the result of rounding non-zero
# g,r,s.
# now, we must determine whether the pre-rounded result was an underflow
# rounded "up" or a normalized number rounded "down".
# so, we do this be re-executing the add using RZ as the rounding mode and
# seeing if the new result is smaller or equal to the current result.
#
fmovm.x FP_SCR1(%a6),&0x40 # load dst op into fp1
#
# Sub: inputs are not both normalized; what are they?
#
fsub_not_norm:
mov.w (tbl_fsub_op.b,%pc,%d1.w*2),%d1
jmp (tbl_fsub_op.b,%pc,%d1.w*1)
swbeg &48
tbl_fsub_op:
short fsub_norm - tbl_fsub_op # NORM - NORM
short fsub_zero_src - tbl_fsub_op # NORM - ZERO
short fsub_inf_src - tbl_fsub_op # NORM - INF
short fsub_res_qnan - tbl_fsub_op # NORM - QNAN
short fsub_norm - tbl_fsub_op # NORM - DENORM
short fsub_res_snan - tbl_fsub_op # NORM - SNAN
short tbl_fsub_op - tbl_fsub_op #
short tbl_fsub_op - tbl_fsub_op #
short fsub_zero_dst - tbl_fsub_op # ZERO - NORM
short fsub_zero_2 - tbl_fsub_op # ZERO - ZERO
short fsub_inf_src - tbl_fsub_op # ZERO - INF
short fsub_res_qnan - tbl_fsub_op # NORM - QNAN
short fsub_zero_dst - tbl_fsub_op # ZERO - DENORM
short fsub_res_snan - tbl_fsub_op # NORM - SNAN
short tbl_fsub_op - tbl_fsub_op #
short tbl_fsub_op - tbl_fsub_op #
short fsub_inf_dst - tbl_fsub_op # INF - NORM
short fsub_inf_dst - tbl_fsub_op # INF - ZERO
short fsub_inf_2 - tbl_fsub_op # INF - INF
short fsub_res_qnan - tbl_fsub_op # NORM - QNAN
short fsub_inf_dst - tbl_fsub_op # INF - DENORM
short fsub_res_snan - tbl_fsub_op # NORM - SNAN
short tbl_fsub_op - tbl_fsub_op #
short tbl_fsub_op - tbl_fsub_op #
short fsub_res_qnan - tbl_fsub_op # QNAN - NORM
short fsub_res_qnan - tbl_fsub_op # QNAN - ZERO
short fsub_res_qnan - tbl_fsub_op # QNAN - INF
short fsub_res_qnan - tbl_fsub_op # QNAN - QNAN
short fsub_res_qnan - tbl_fsub_op # QNAN - DENORM
short fsub_res_snan - tbl_fsub_op # QNAN - SNAN
short tbl_fsub_op - tbl_fsub_op #
short tbl_fsub_op - tbl_fsub_op #
short fsub_norm - tbl_fsub_op # DENORM - NORM
short fsub_zero_src - tbl_fsub_op # DENORM - ZERO
short fsub_inf_src - tbl_fsub_op # DENORM - INF
short fsub_res_qnan - tbl_fsub_op # NORM - QNAN
short fsub_norm - tbl_fsub_op # DENORM - DENORM
short fsub_res_snan - tbl_fsub_op # NORM - SNAN
short tbl_fsub_op - tbl_fsub_op #
short tbl_fsub_op - tbl_fsub_op #
short fsub_res_snan - tbl_fsub_op # SNAN - NORM
short fsub_res_snan - tbl_fsub_op # SNAN - ZERO
short fsub_res_snan - tbl_fsub_op # SNAN - INF
short fsub_res_snan - tbl_fsub_op # SNAN - QNAN
short fsub_res_snan - tbl_fsub_op # SNAN - DENORM
short fsub_res_snan - tbl_fsub_op # SNAN - SNAN
short tbl_fsub_op - tbl_fsub_op #
short tbl_fsub_op - tbl_fsub_op #
#
# both operands are ZEROes
#
fsub_zero_2:
mov.b SRC_EX(%a0),%d0
mov.b DST_EX(%a1),%d1
eor.b %d1,%d0
bpl.b fsub_zero_2_chk_rm
# the signs are opposite, so, return a ZERO w/ the sign of the dst ZERO
tst.b %d0 # is dst negative?
bmi.b fsub_zero_2_rm # yes
fmov.s &0x00000000,%fp0 # no; return +ZERO
mov.b &z_bmask,FPSR_CC(%a6) # set Z
rts
#
# the ZEROes have the same signs:
# - therefore, we return +ZERO if the rounding mode is RN,RZ, or RP
# - -ZERO is returned in the case of RM.
#
fsub_zero_2_chk_rm:
mov.b 3+L_SCR3(%a6),%d1
andi.b &0x30,%d1 # extract rnd mode
cmpi.b %d1,&rm_mode*0x10 # is rnd mode = RM?
beq.b fsub_zero_2_rm # yes
fmov.s &0x00000000,%fp0 # no; return +ZERO
mov.b &z_bmask,FPSR_CC(%a6) # set Z
rts
#
# one operand is a ZERO and the other is a DENORM or a NORM.
# scale the DENORM or NORM and jump to the regular fsub routine.
#
fsub_zero_dst:
mov.w SRC_EX(%a0),FP_SCR0_EX(%a6)
mov.l SRC_HI(%a0),FP_SCR0_HI(%a6)
mov.l SRC_LO(%a0),FP_SCR0_LO(%a6)
bsr.l scale_to_zero_src # scale the operand
clr.w FP_SCR1_EX(%a6)
clr.l FP_SCR1_HI(%a6)
clr.l FP_SCR1_LO(%a6)
bra.w fsub_zero_entry # go execute fsub
#
# both operands are INFs. an OPERR will result if the INFs have the
# same signs. else,
#
fsub_inf_2:
mov.b SRC_EX(%a0),%d0 # exclusive or the signs
mov.b DST_EX(%a1),%d1
eor.b %d1,%d0
bpl.l res_operr # weed out (-INF)+(+INF)
# ok, so it's not an OPERR. but we do have to remember to return
# the src INF since that's where the 881/882 gets the j-bit.
fsub_inf_src:
fmovm.x SRC(%a0),&0x80 # return src INF
fneg.x %fp0 # invert sign
fbge.w fsub_inf_done # sign is now positive
mov.b &neg_bmask+inf_bmask,FPSR_CC(%a6) # set INF/NEG
rts
fsub_inf_dst:
fmovm.x DST(%a1),&0x80 # return dst INF
tst.b DST_EX(%a1) # is INF negative?
bpl.b fsub_inf_done # no
mov.b &neg_bmask+inf_bmask,FPSR_CC(%a6) # set INF/NEG
rts
fsub_inf_done:
mov.b &inf_bmask,FPSR_CC(%a6) # set INF
rts
#########################################################################
# XDEF **************************************************************** #
# fsqrt(): emulates the fsqrt instruction #
# fssqrt(): emulates the fssqrt instruction #
# fdsqrt(): emulates the fdsqrt instruction #
# #
# XREF **************************************************************** #
# scale_sqrt() - scale the source operand #
# unf_res() - return default underflow result #
# ovf_res() - return default overflow result #
# res_qnan_1op() - return QNAN result #
# res_snan_1op() - return SNAN result #
# #
# INPUT *************************************************************** #
# a0 = pointer to extended precision source operand #
# d0 rnd prec,mode #
# #
# OUTPUT ************************************************************** #
# fp0 = result #
# fp1 = EXOP (if exception occurred) #
# #
# ALGORITHM *********************************************************** #
# Handle NANs, infinities, and zeroes as special cases. Divide #
# norms/denorms into ext/sgl/dbl precision. #
# For norms/denorms, scale the exponents such that a sqrt #
# instruction won't cause an exception. Use the regular fsqrt to #
# compute a result. Check if the regular operands would have taken #
# an exception. If so, return the default overflow/underflow result #
# and return the EXOP if exceptions are enabled. Else, scale the #
# result operand to the proper exponent. #
# #
#########################################################################
#
# operand is either single or double
#
fsqrt_not_ext:
cmpi.b %d0,&s_mode*0x10 # separate sgl/dbl prec
bne.w fsqrt_dbl
#
# operand is to be rounded to single precision
#
fsqrt_sgl:
mov.w SRC_EX(%a0),FP_SCR0_EX(%a6)
mov.l SRC_HI(%a0),FP_SCR0_HI(%a6)
mov.l SRC_LO(%a0),FP_SCR0_LO(%a6)
bsr.l scale_sqrt # calculate scale factor
cmpi.l %d0,&0x3fff-0x3f81 # will move in underflow?
beq.w fsqrt_sd_may_unfl
bgt.w fsqrt_sd_unfl # yes; go handle underflow
cmpi.l %d0,&0x3fff-0x407f # will move in overflow?
beq.w fsqrt_sd_may_ovfl # maybe; go check
blt.w fsqrt_sd_ovfl # yes; go handle overflow
#
# operand will NOT overflow or underflow when moved in to the fp reg file
#
fsqrt_sd_normal:
fmov.l &0x0,%fpsr # clear FPSR
fmov.l L_SCR3(%a6),%fpcr # set FPCR
fsqrt.x FP_SCR0(%a6),%fp0 # perform absolute
fmov.l %fpsr,%d1 # save FPSR
fmov.l &0x0,%fpcr # clear FPCR
or.l %d1,USER_FPSR(%a6) # save INEX2,N
fsqrt_sd_normal_exit:
mov.l %d2,-(%sp) # save d2
fmovm.x &0x80,FP_SCR0(%a6) # store out result
mov.w FP_SCR0_EX(%a6),%d1 # load sgn,exp
mov.l %d1,%d2 # make a copy
andi.l &0x7fff,%d1 # strip sign
sub.l %d0,%d1 # add scale factor
andi.w &0x8000,%d2 # keep old sign
or.w %d1,%d2 # concat old sign,new exp
mov.w %d2,FP_SCR0_EX(%a6) # insert new exponent
mov.l (%sp)+,%d2 # restore d2
fmovm.x FP_SCR0(%a6),&0x80 # return result in fp0
rts
#
# operand is to be rounded to double precision
#
fsqrt_dbl:
mov.w SRC_EX(%a0),FP_SCR0_EX(%a6)
mov.l SRC_HI(%a0),FP_SCR0_HI(%a6)
mov.l SRC_LO(%a0),FP_SCR0_LO(%a6)
bsr.l scale_sqrt # calculate scale factor
cmpi.l %d0,&0x3fff-0x3c01 # will move in underflow?
beq.w fsqrt_sd_may_unfl
bgt.b fsqrt_sd_unfl # yes; go handle underflow
cmpi.l %d0,&0x3fff-0x43ff # will move in overflow?
beq.w fsqrt_sd_may_ovfl # maybe; go check
blt.w fsqrt_sd_ovfl # yes; go handle overflow
bra.w fsqrt_sd_normal # no; ho handle normalized op
# we're on the line here and the distinguising characteristic is whether
# the exponent is 3fff or 3ffe. if it's 3ffe, then it's a safe number
# elsewise fall through to underflow.
fsqrt_sd_may_unfl:
btst &0x0,1+FP_SCR0_EX(%a6) # is exponent 0x3fff?
bne.w fsqrt_sd_normal # yes, so no underflow
#
# operand WILL underflow when moved in to the fp register file
#
fsqrt_sd_unfl:
bset &unfl_bit,FPSR_EXCEPT(%a6) # set unfl exc bit
fmov.l &rz_mode*0x10,%fpcr # set FPCR
fmov.l &0x0,%fpsr # clear FPSR
fsqrt.x FP_SCR0(%a6),%fp0 # execute square root
fmov.l %fpsr,%d1 # save status
fmov.l &0x0,%fpcr # clear FPCR
or.l %d1,USER_FPSR(%a6) # save INEX2,N
# if underflow or inexact is enabled, go calculate EXOP first.
mov.b FPCR_ENABLE(%a6),%d1
andi.b &0x0b,%d1 # is UNFL or INEX enabled?
bne.b fsqrt_sd_unfl_ena # yes
fsqrt_sd_unfl_dis:
fmovm.x &0x80,FP_SCR0(%a6) # store out result
lea FP_SCR0(%a6),%a0 # pass: result addr
mov.l L_SCR3(%a6),%d1 # pass: rnd prec,mode
bsr.l unf_res # calculate default result
or.b %d0,FPSR_CC(%a6) # set possible 'Z' ccode
fmovm.x FP_SCR0(%a6),&0x80 # return default result in fp0
rts
#
# operand will underflow AND underflow is enabled.
# therefore, we must return the result rounded to extended precision.
#
fsqrt_sd_unfl_ena:
mov.l FP_SCR0_HI(%a6),FP_SCR1_HI(%a6)
mov.l FP_SCR0_LO(%a6),FP_SCR1_LO(%a6)
mov.w FP_SCR0_EX(%a6),%d1 # load current exponent
mov.l %d2,-(%sp) # save d2
mov.l %d1,%d2 # make a copy
andi.l &0x7fff,%d1 # strip sign
andi.w &0x8000,%d2 # keep old sign
sub.l %d0,%d1 # subtract scale factor
addi.l &0x6000,%d1 # add new bias
andi.w &0x7fff,%d1
or.w %d2,%d1 # concat new sign,new exp
mov.w %d1,FP_SCR1_EX(%a6) # insert new exp
fmovm.x FP_SCR1(%a6),&0x40 # return EXOP in fp1
mov.l (%sp)+,%d2 # restore d2
bra.b fsqrt_sd_unfl_dis
#
# operand WILL overflow.
#
fsqrt_sd_ovfl:
fmov.l &0x0,%fpsr # clear FPSR
fmov.l L_SCR3(%a6),%fpcr # set FPCR
fsqrt.x FP_SCR0(%a6),%fp0 # perform square root
fmov.l &0x0,%fpcr # clear FPCR
fmov.l %fpsr,%d1 # save FPSR
or.l %d1,USER_FPSR(%a6) # save INEX2,N
fsqrt_sd_ovfl_tst:
or.l &ovfl_inx_mask,USER_FPSR(%a6) # set ovfl/aovfl/ainex
mov.b FPCR_ENABLE(%a6),%d1
andi.b &0x13,%d1 # is OVFL or INEX enabled?
bne.b fsqrt_sd_ovfl_ena # yes
#
# OVFL is not enabled; therefore, we must create the default result by
# calling ovf_res().
#
fsqrt_sd_ovfl_dis:
btst &neg_bit,FPSR_CC(%a6) # is result negative?
sne %d1 # set sign param accordingly
mov.l L_SCR3(%a6),%d0 # pass: prec,mode
bsr.l ovf_res # calculate default result
or.b %d0,FPSR_CC(%a6) # set INF,N if applicable
fmovm.x (%a0),&0x80 # return default result in fp0
rts
#
# OVFL is enabled.
# the INEX2 bit has already been updated by the round to the correct precision.
# now, round to extended(and don't alter the FPSR).
#
fsqrt_sd_ovfl_ena:
mov.l %d2,-(%sp) # save d2
mov.w FP_SCR0_EX(%a6),%d1 # fetch {sgn,exp}
mov.l %d1,%d2 # make a copy
andi.l &0x7fff,%d1 # strip sign
andi.w &0x8000,%d2 # keep old sign
sub.l %d0,%d1 # add scale factor
subi.l &0x6000,%d1 # subtract bias
andi.w &0x7fff,%d1
or.w %d2,%d1 # concat sign,exp
mov.w %d1,FP_SCR0_EX(%a6) # insert new exponent
fmovm.x FP_SCR0(%a6),&0x40 # return EXOP in fp1
mov.l (%sp)+,%d2 # restore d2
bra.b fsqrt_sd_ovfl_dis
#
# the move in MAY underflow. so...
#
fsqrt_sd_may_ovfl:
btst &0x0,1+FP_SCR0_EX(%a6) # is exponent 0x3fff?
bne.w fsqrt_sd_ovfl # yes, so overflow
fmov.l &0x0,%fpsr # clear FPSR
fmov.l L_SCR3(%a6),%fpcr # set FPCR
fsqrt.x FP_SCR0(%a6),%fp0 # perform absolute
fmov.l %fpsr,%d1 # save status
fmov.l &0x0,%fpcr # clear FPCR
or.l %d1,USER_FPSR(%a6) # save INEX2,N
fmov.x %fp0,%fp1 # make a copy of result
fcmp.b %fp1,&0x1 # is |result| >= 1.b?
fbge.w fsqrt_sd_ovfl_tst # yes; overflow has occurred
# no, it didn't overflow; we have correct result
bra.w fsqrt_sd_normal_exit
#
# input is not normalized; what is it?
#
fsqrt_not_norm:
cmpi.b %d1,&DENORM # weed out DENORM
beq.w fsqrt_denorm
cmpi.b %d1,&ZERO # weed out ZERO
beq.b fsqrt_zero
cmpi.b %d1,&INF # weed out INF
beq.b fsqrt_inf
cmpi.b %d1,&SNAN # weed out SNAN
beq.l res_snan_1op
bra.l res_qnan_1op
#
# fsqrt(+0) = +0
# fsqrt(-0) = -0
# fsqrt(+INF) = +INF
# fsqrt(-INF) = OPERR
#
fsqrt_zero:
tst.b SRC_EX(%a0) # is ZERO positive or negative?
bmi.b fsqrt_zero_m # negative
fsqrt_zero_p:
fmov.s &0x00000000,%fp0 # return +ZERO
mov.b &z_bmask,FPSR_CC(%a6) # set 'Z' ccode bit
rts
fsqrt_zero_m:
fmov.s &0x80000000,%fp0 # return -ZERO
mov.b &z_bmask+neg_bmask,FPSR_CC(%a6) # set 'Z','N' ccode bits
rts
fsqrt_inf:
tst.b SRC_EX(%a0) # is INF positive or negative?
bmi.l res_operr # negative
fsqrt_inf_p:
fmovm.x SRC(%a0),&0x80 # return +INF in fp0
mov.b &inf_bmask,FPSR_CC(%a6) # set 'I' ccode bit
rts
#########################################################################
# XDEF **************************************************************** #
# fetch_dreg(): fetch register according to index in d1 #
# #
# XREF **************************************************************** #
# None #
# #
# INPUT *************************************************************** #
# d1 = index of register to fetch from #
# #
# OUTPUT ************************************************************** #
# d0 = value of register fetched #
# #
# ALGORITHM *********************************************************** #
# According to the index value in d1 which can range from zero #
# to fifteen, load the corresponding register file value (where #
# address register indexes start at 8). D0/D1/A0/A1/A6/A7 are on the #
# stack. The rest should still be in their original places. #
# #
#########################################################################
# this routine leaves d1 intact for subsequent store_dreg calls.
global fetch_dreg
fetch_dreg:
mov.w (tbl_fdreg.b,%pc,%d1.w*2),%d0
jmp (tbl_fdreg.b,%pc,%d0.w*1)
tbl_fdreg:
short fdreg0 - tbl_fdreg
short fdreg1 - tbl_fdreg
short fdreg2 - tbl_fdreg
short fdreg3 - tbl_fdreg
short fdreg4 - tbl_fdreg
short fdreg5 - tbl_fdreg
short fdreg6 - tbl_fdreg
short fdreg7 - tbl_fdreg
short fdreg8 - tbl_fdreg
short fdreg9 - tbl_fdreg
short fdrega - tbl_fdreg
short fdregb - tbl_fdreg
short fdregc - tbl_fdreg
short fdregd - tbl_fdreg
short fdrege - tbl_fdreg
short fdregf - tbl_fdreg
#########################################################################
# XDEF **************************************************************** #
# store_dreg_l(): store longword to data register specified by d1 #
# #
# XREF **************************************************************** #
# None #
# #
# INPUT *************************************************************** #
# d0 = longowrd value to store #
# d1 = index of register to fetch from #
# #
# OUTPUT ************************************************************** #
# (data register is updated) #
# #
# ALGORITHM *********************************************************** #
# According to the index value in d1, store the longword value #
# in d0 to the corresponding data register. D0/D1 are on the stack #
# while the rest are in their initial places. #
# #
#########################################################################
global store_dreg_l
store_dreg_l:
mov.w (tbl_sdregl.b,%pc,%d1.w*2),%d1
jmp (tbl_sdregl.b,%pc,%d1.w*1)
tbl_sdregl:
short sdregl0 - tbl_sdregl
short sdregl1 - tbl_sdregl
short sdregl2 - tbl_sdregl
short sdregl3 - tbl_sdregl
short sdregl4 - tbl_sdregl
short sdregl5 - tbl_sdregl
short sdregl6 - tbl_sdregl
short sdregl7 - tbl_sdregl
#########################################################################
# XDEF **************************************************************** #
# store_dreg_w(): store word to data register specified by d1 #
# #
# XREF **************************************************************** #
# None #
# #
# INPUT *************************************************************** #
# d0 = word value to store #
# d1 = index of register to fetch from #
# #
# OUTPUT ************************************************************** #
# (data register is updated) #
# #
# ALGORITHM *********************************************************** #
# According to the index value in d1, store the word value #
# in d0 to the corresponding data register. D0/D1 are on the stack #
# while the rest are in their initial places. #
# #
#########################################################################
global store_dreg_w
store_dreg_w:
mov.w (tbl_sdregw.b,%pc,%d1.w*2),%d1
jmp (tbl_sdregw.b,%pc,%d1.w*1)
tbl_sdregw:
short sdregw0 - tbl_sdregw
short sdregw1 - tbl_sdregw
short sdregw2 - tbl_sdregw
short sdregw3 - tbl_sdregw
short sdregw4 - tbl_sdregw
short sdregw5 - tbl_sdregw
short sdregw6 - tbl_sdregw
short sdregw7 - tbl_sdregw
#########################################################################
# XDEF **************************************************************** #
# store_dreg_b(): store byte to data register specified by d1 #
# #
# XREF **************************************************************** #
# None #
# #
# INPUT *************************************************************** #
# d0 = byte value to store #
# d1 = index of register to fetch from #
# #
# OUTPUT ************************************************************** #
# (data register is updated) #
# #
# ALGORITHM *********************************************************** #
# According to the index value in d1, store the byte value #
# in d0 to the corresponding data register. D0/D1 are on the stack #
# while the rest are in their initial places. #
# #
#########################################################################
global store_dreg_b
store_dreg_b:
mov.w (tbl_sdregb.b,%pc,%d1.w*2),%d1
jmp (tbl_sdregb.b,%pc,%d1.w*1)
tbl_sdregb:
short sdregb0 - tbl_sdregb
short sdregb1 - tbl_sdregb
short sdregb2 - tbl_sdregb
short sdregb3 - tbl_sdregb
short sdregb4 - tbl_sdregb
short sdregb5 - tbl_sdregb
short sdregb6 - tbl_sdregb
short sdregb7 - tbl_sdregb
#########################################################################
# XDEF **************************************************************** #
# inc_areg(): increment an address register by the value in d0 #
# #
# XREF **************************************************************** #
# None #
# #
# INPUT *************************************************************** #
# d0 = amount to increment by #
# d1 = index of address register to increment #
# #
# OUTPUT ************************************************************** #
# (address register is updated) #
# #
# ALGORITHM *********************************************************** #
# Typically used for an instruction w/ a post-increment <ea>, #
# this routine adds the increment value in d0 to the address register #
# specified by d1. A0/A1/A6/A7 reside on the stack. The rest reside #
# in their original places. #
# For a7, if the increment amount is one, then we have to #
# increment by two. For any a7 update, set the mia7_flag so that if #
# an access error exception occurs later in emulation, this address #
# register update can be undone. #
# #
#########################################################################
global inc_areg
inc_areg:
mov.w (tbl_iareg.b,%pc,%d1.w*2),%d1
jmp (tbl_iareg.b,%pc,%d1.w*1)
tbl_iareg:
short iareg0 - tbl_iareg
short iareg1 - tbl_iareg
short iareg2 - tbl_iareg
short iareg3 - tbl_iareg
short iareg4 - tbl_iareg
short iareg5 - tbl_iareg
short iareg6 - tbl_iareg
short iareg7 - tbl_iareg
#########################################################################
# XDEF **************************************************************** #
# dec_areg(): decrement an address register by the value in d0 #
# #
# XREF **************************************************************** #
# None #
# #
# INPUT *************************************************************** #
# d0 = amount to decrement by #
# d1 = index of address register to decrement #
# #
# OUTPUT ************************************************************** #
# (address register is updated) #
# #
# ALGORITHM *********************************************************** #
# Typically used for an instruction w/ a pre-decrement <ea>, #
# this routine adds the decrement value in d0 to the address register #
# specified by d1. A0/A1/A6/A7 reside on the stack. The rest reside #
# in their original places. #
# For a7, if the decrement amount is one, then we have to #
# decrement by two. For any a7 update, set the mda7_flag so that if #
# an access error exception occurs later in emulation, this address #
# register update can be undone. #
# #
#########################################################################
global dec_areg
dec_areg:
mov.w (tbl_dareg.b,%pc,%d1.w*2),%d1
jmp (tbl_dareg.b,%pc,%d1.w*1)
tbl_dareg:
short dareg0 - tbl_dareg
short dareg1 - tbl_dareg
short dareg2 - tbl_dareg
short dareg3 - tbl_dareg
short dareg4 - tbl_dareg
short dareg5 - tbl_dareg
short dareg6 - tbl_dareg
short dareg7 - tbl_dareg
#########################################################################
# XDEF **************************************************************** #
# load_fpn1(): load FP register value into FP_SRC(a6). #
# #
# XREF **************************************************************** #
# None #
# #
# INPUT *************************************************************** #
# d0 = index of FP register to load #
# #
# OUTPUT ************************************************************** #
# FP_SRC(a6) = value loaded from FP register file #
# #
# ALGORITHM *********************************************************** #
# Using the index in d0, load FP_SRC(a6) with a number from the #
# FP register file. #
# #
#########################################################################
global load_fpn1
load_fpn1:
mov.w (tbl_load_fpn1.b,%pc,%d0.w*2), %d0
jmp (tbl_load_fpn1.b,%pc,%d0.w*1)
tbl_load_fpn1:
short load_fpn1_0 - tbl_load_fpn1
short load_fpn1_1 - tbl_load_fpn1
short load_fpn1_2 - tbl_load_fpn1
short load_fpn1_3 - tbl_load_fpn1
short load_fpn1_4 - tbl_load_fpn1
short load_fpn1_5 - tbl_load_fpn1
short load_fpn1_6 - tbl_load_fpn1
short load_fpn1_7 - tbl_load_fpn1
#########################################################################
# XDEF **************************************************************** #
# load_fpn2(): load FP register value into FP_DST(a6). #
# #
# XREF **************************************************************** #
# None #
# #
# INPUT *************************************************************** #
# d0 = index of FP register to load #
# #
# OUTPUT ************************************************************** #
# FP_DST(a6) = value loaded from FP register file #
# #
# ALGORITHM *********************************************************** #
# Using the index in d0, load FP_DST(a6) with a number from the #
# FP register file. #
# #
#########################################################################
global load_fpn2
load_fpn2:
mov.w (tbl_load_fpn2.b,%pc,%d0.w*2), %d0
jmp (tbl_load_fpn2.b,%pc,%d0.w*1)
tbl_load_fpn2:
short load_fpn2_0 - tbl_load_fpn2
short load_fpn2_1 - tbl_load_fpn2
short load_fpn2_2 - tbl_load_fpn2
short load_fpn2_3 - tbl_load_fpn2
short load_fpn2_4 - tbl_load_fpn2
short load_fpn2_5 - tbl_load_fpn2
short load_fpn2_6 - tbl_load_fpn2
short load_fpn2_7 - tbl_load_fpn2
#########################################################################
# XDEF **************************************************************** #
# store_fpreg(): store an fp value to the fpreg designated d0. #
# #
# XREF **************************************************************** #
# None #
# #
# INPUT *************************************************************** #
# fp0 = extended precision value to store #
# d0 = index of floating-point register #
# #
# OUTPUT ************************************************************** #
# None #
# #
# ALGORITHM *********************************************************** #
# Store the value in fp0 to the FP register designated by the #
# value in d0. The FP number can be DENORM or SNAN so we have to be #
# careful that we don't take an exception here. #
# #
#########################################################################
global store_fpreg
store_fpreg:
mov.w (tbl_store_fpreg.b,%pc,%d0.w*2), %d0
jmp (tbl_store_fpreg.b,%pc,%d0.w*1)
tbl_store_fpreg:
short store_fpreg_0 - tbl_store_fpreg
short store_fpreg_1 - tbl_store_fpreg
short store_fpreg_2 - tbl_store_fpreg
short store_fpreg_3 - tbl_store_fpreg
short store_fpreg_4 - tbl_store_fpreg
short store_fpreg_5 - tbl_store_fpreg
short store_fpreg_6 - tbl_store_fpreg
short store_fpreg_7 - tbl_store_fpreg
#########################################################################
# XDEF **************************************************************** #
# get_packed(): fetch a packed operand from memory and then #
# convert it to a floating-point binary number. #
# #
# XREF **************************************************************** #
# _dcalc_ea() - calculate the correct <ea> #
# _mem_read() - fetch the packed operand from memory #
# facc_in_x() - the fetch failed so jump to special exit code #
# decbin() - convert packed to binary extended precision #
# #
# INPUT *************************************************************** #
# None #
# #
# OUTPUT ************************************************************** #
# If no failure on _mem_read(): #
# FP_SRC(a6) = packed operand now as a binary FP number #
# #
# ALGORITHM *********************************************************** #
# Get the correct <ea> whihc is the value on the exception stack #
# frame w/ maybe a correction factor if the <ea> is -(an) or (an)+. #
# Then, fetch the operand from memory. If the fetch fails, exit #
# through facc_in_x(). #
# If the packed operand is a ZERO,NAN, or INF, convert it to #
# its binary representation here. Else, call decbin() which will #
# convert the packed value to an extended precision binary value. #
# #
#########################################################################
# the stacked <ea> for packed is correct except for -(An).
# the base reg must be updated for both -(An) and (An)+.
global get_packed
get_packed:
mov.l &0xc,%d0 # packed is 12 bytes
bsr.l _dcalc_ea # fetch <ea>; correct An
lea FP_SRC(%a6),%a1 # pass: ptr to super dst
mov.l &0xc,%d0 # pass: 12 bytes
bsr.l _dmem_read # read packed operand
tst.l %d1 # did dfetch fail?
bne.l facc_in_x # yes
# The packed operand is an INF or a NAN if the exponent field is all ones.
bfextu FP_SRC(%a6){&1:&15},%d0 # get exp
cmpi.w %d0,&0x7fff # INF or NAN?
bne.b gp_try_zero # no
rts # operand is an INF or NAN
# The packed operand is a zero if the mantissa is all zero, else it's
# a normal packed op.
gp_try_zero:
mov.b 3+FP_SRC(%a6),%d0 # get byte 4
andi.b &0x0f,%d0 # clear all but last nybble
bne.b gp_not_spec # not a zero
tst.l FP_SRC_HI(%a6) # is lw 2 zero?
bne.b gp_not_spec # not a zero
tst.l FP_SRC_LO(%a6) # is lw 3 zero?
bne.b gp_not_spec # not a zero
rts # operand is a ZERO
gp_not_spec:
lea FP_SRC(%a6),%a0 # pass: ptr to packed op
bsr.l decbin # convert to extended
fmovm.x &0x80,FP_SRC(%a6) # make this the srcop
rts
#########################################################################
# decbin(): Converts normalized packed bcd value pointed to by register #
# a0 to extended-precision value in fp0. #
# #
# INPUT *************************************************************** #
# a0 = pointer to normalized packed bcd value #
# #
# OUTPUT ************************************************************** #
# fp0 = exact fp representation of the packed bcd value. #
# #
# ALGORITHM *********************************************************** #
# Expected is a normal bcd (i.e. non-exceptional; all inf, zero, #
# and NaN operands are dispatched without entering this routine) #
# value in 68881/882 format at location (a0). #
# #
# A1. Convert the bcd exponent to binary by successive adds and #
# muls. Set the sign according to SE. Subtract 16 to compensate #
# for the mantissa which is to be interpreted as 17 integer #
# digits, rather than 1 integer and 16 fraction digits. #
# Note: this operation can never overflow. #
# #
# A2. Convert the bcd mantissa to binary by successive #
# adds and muls in FP0. Set the sign according to SM. #
# The mantissa digits will be converted with the decimal point #
# assumed following the least-significant digit. #
# Note: this operation can never overflow. #
# #
# A3. Count the number of leading/trailing zeros in the #
# bcd string. If SE is positive, count the leading zeros; #
# if negative, count the trailing zeros. Set the adjusted #
# exponent equal to the exponent from A1 and the zero count #
# added if SM = 1 and subtracted if SM = 0. Scale the #
# mantissa the equivalent of forcing in the bcd value: #
# #
# SM = 0 a non-zero digit in the integer position #
# SM = 1 a non-zero digit in Mant0, lsd of the fraction #
# #
# this will insure that any value, regardless of its #
# representation (ex. 0.1E2, 1E1, 10E0, 100E-1), is converted #
# consistently. #
# #
# A4. Calculate the factor 10^exp in FP1 using a table of #
# 10^(2^n) values. To reduce the error in forming factors #
# greater than 10^27, a directed rounding scheme is used with #
# tables rounded to RN, RM, and RP, according to the table #
# in the comments of the pwrten section. #
# #
# A5. Form the final binary number by scaling the mantissa by #
# the exponent factor. This is done by multiplying the #
# mantissa in FP0 by the factor in FP1 if the adjusted #
# exponent sign is positive, and dividing FP0 by FP1 if #
# it is negative. #
# #
# Clean up and return. Check if the final mul or div was inexact. #
# If so, set INEX1 in USER_FPSR. #
# #
#########################################################################
#
# PTENRN, PTENRM, and PTENRP are arrays of powers of 10 rounded
# to nearest, minus, and plus, respectively. The tables include
# 10**{1,2,4,8,16,32,64,128,256,512,1024,2048,4096}. No rounding
# is required until the power is greater than 27, however, all
# tables include the first 5 for ease of indexing.
#
RTABLE:
byte 0,0,0,0
byte 2,3,2,3
byte 2,3,3,2
byte 3,2,2,3
set FNIBS,7
set FSTRT,0
set ESTRT,4
set EDIGITS,2
global decbin
decbin:
mov.l 0x0(%a0),FP_SCR0_EX(%a6) # make a copy of input
mov.l 0x4(%a0),FP_SCR0_HI(%a6) # so we don't alter it
mov.l 0x8(%a0),FP_SCR0_LO(%a6)
lea FP_SCR0(%a6),%a0
movm.l &0x3c00,-(%sp) # save d2-d5
fmovm.x &0x1,-(%sp) # save fp1
#
# Calculate exponent:
# 1. Copy bcd value in memory for use as a working copy.
# 2. Calculate absolute value of exponent in d1 by mul and add.
# 3. Correct for exponent sign.
# 4. Subtract 16 to compensate for interpreting the mant as all integer digits.
# (i.e., all digits assumed left of the decimal point.)
#
# Register usage:
#
# calc_e:
# (*) d0: temp digit storage
# (*) d1: accumulator for binary exponent
# (*) d2: digit count
# (*) d3: offset pointer
# ( ) d4: first word of bcd
# ( ) a0: pointer to working bcd value
# ( ) a6: pointer to original bcd value
# (*) FP_SCR1: working copy of original bcd value
# (*) L_SCR1: copy of original exponent word
#
calc_e:
mov.l &EDIGITS,%d2 # # of nibbles (digits) in fraction part
mov.l &ESTRT,%d3 # counter to pick up digits
mov.l (%a0),%d4 # get first word of bcd
clr.l %d1 # zero d1 for accumulator
e_gd:
mulu.l &0xa,%d1 # mul partial product by one digit place
bfextu %d4{%d3:&4},%d0 # get the digit and zero extend into d0
add.l %d0,%d1 # d1 = d1 + d0
addq.b &4,%d3 # advance d3 to the next digit
dbf.w %d2,e_gd # if we have used all 3 digits, exit loop
btst &30,%d4 # get SE
beq.b e_pos # don't negate if pos
neg.l %d1 # negate before subtracting
e_pos:
sub.l &16,%d1 # sub to compensate for shift of mant
bge.b e_save # if still pos, do not neg
neg.l %d1 # now negative, make pos and set SE
or.l &0x40000000,%d4 # set SE in d4,
or.l &0x40000000,(%a0) # and in working bcd
e_save:
mov.l %d1,-(%sp) # save exp on stack
#
#
# Calculate mantissa:
# 1. Calculate absolute value of mantissa in fp0 by mul and add.
# 2. Correct for mantissa sign.
# (i.e., all digits assumed left of the decimal point.)
#
# Register usage:
#
# calc_m:
# (*) d0: temp digit storage
# (*) d1: lword counter
# (*) d2: digit count
# (*) d3: offset pointer
# ( ) d4: words 2 and 3 of bcd
# ( ) a0: pointer to working bcd value
# ( ) a6: pointer to original bcd value
# (*) fp0: mantissa accumulator
# ( ) FP_SCR1: working copy of original bcd value
# ( ) L_SCR1: copy of original exponent word
#
calc_m:
mov.l &1,%d1 # word counter, init to 1
fmov.s &0x00000000,%fp0 # accumulator
#
#
# Since the packed number has a long word between the first & second parts,
# get the integer digit then skip down & get the rest of the
# mantissa. We will unroll the loop once.
#
bfextu (%a0){&28:&4},%d0 # integer part is ls digit in long word
fadd.b %d0,%fp0 # add digit to sum in fp0
#
#
# Get the rest of the mantissa.
#
loadlw:
mov.l (%a0,%d1.L*4),%d4 # load mantissa lonqword into d4
mov.l &FSTRT,%d3 # counter to pick up digits
mov.l &FNIBS,%d2 # reset number of digits per a0 ptr
md2b:
fmul.s &0x41200000,%fp0 # fp0 = fp0 * 10
bfextu %d4{%d3:&4},%d0 # get the digit and zero extend
fadd.b %d0,%fp0 # fp0 = fp0 + digit
#
#
# If all the digits (8) in that long word have been converted (d2=0),
# then inc d1 (=2) to point to the next long word and reset d3 to 0
# to initialize the digit offset, and set d2 to 7 for the digit count;
# else continue with this long word.
#
addq.b &4,%d3 # advance d3 to the next digit
dbf.w %d2,md2b # check for last digit in this lw
nextlw:
addq.l &1,%d1 # inc lw pointer in mantissa
cmp.l %d1,&2 # test for last lw
ble.b loadlw # if not, get last one
#
# Check the sign of the mant and make the value in fp0 the same sign.
#
m_sign:
btst &31,(%a0) # test sign of the mantissa
beq.b ap_st_z # if clear, go to append/strip zeros
fneg.x %fp0 # if set, negate fp0
#
# Append/strip zeros:
#
# For adjusted exponents which have an absolute value greater than 27*,
# this routine calculates the amount needed to normalize the mantissa
# for the adjusted exponent. That number is subtracted from the exp
# if the exp was positive, and added if it was negative. The purpose
# of this is to reduce the value of the exponent and the possibility
# of error in calculation of pwrten.
#
# 1. Branch on the sign of the adjusted exponent.
# 2p.(positive exp)
# 2. Check M16 and the digits in lwords 2 and 3 in decending order.
# 3. Add one for each zero encountered until a non-zero digit.
# 4. Subtract the count from the exp.
# 5. Check if the exp has crossed zero in #3 above; make the exp abs
# and set SE.
# 6. Multiply the mantissa by 10**count.
# 2n.(negative exp)
# 2. Check the digits in lwords 3 and 2 in decending order.
# 3. Add one for each zero encountered until a non-zero digit.
# 4. Add the count to the exp.
# 5. Check if the exp has crossed zero in #3 above; clear SE.
# 6. Divide the mantissa by 10**count.
#
# *Why 27? If the adjusted exponent is within -28 < expA < 28, than
# any adjustment due to append/strip zeros will drive the resultane
# exponent towards zero. Since all pwrten constants with a power
# of 27 or less are exact, there is no need to use this routine to
# attempt to lessen the resultant exponent.
#
# Register usage:
#
# ap_st_z:
# (*) d0: temp digit storage
# (*) d1: zero count
# (*) d2: digit count
# (*) d3: offset pointer
# ( ) d4: first word of bcd
# (*) d5: lword counter
# ( ) a0: pointer to working bcd value
# ( ) FP_SCR1: working copy of original bcd value
# ( ) L_SCR1: copy of original exponent word
#
#
# First check the absolute value of the exponent to see if this
# routine is necessary. If so, then check the sign of the exponent
# and do append (+) or strip (-) zeros accordingly.
# This section handles a positive adjusted exponent.
#
ap_st_z:
mov.l (%sp),%d1 # load expA for range test
cmp.l %d1,&27 # test is with 27
ble.w pwrten # if abs(expA) <28, skip ap/st zeros
btst &30,(%a0) # check sign of exp
bne.b ap_st_n # if neg, go to neg side
clr.l %d1 # zero count reg
mov.l (%a0),%d4 # load lword 1 to d4
bfextu %d4{&28:&4},%d0 # get M16 in d0
bne.b ap_p_fx # if M16 is non-zero, go fix exp
addq.l &1,%d1 # inc zero count
mov.l &1,%d5 # init lword counter
mov.l (%a0,%d5.L*4),%d4 # get lword 2 to d4
bne.b ap_p_cl # if lw 2 is zero, skip it
addq.l &8,%d1 # and inc count by 8
addq.l &1,%d5 # inc lword counter
mov.l (%a0,%d5.L*4),%d4 # get lword 3 to d4
ap_p_cl:
clr.l %d3 # init offset reg
mov.l &7,%d2 # init digit counter
ap_p_gd:
bfextu %d4{%d3:&4},%d0 # get digit
bne.b ap_p_fx # if non-zero, go to fix exp
addq.l &4,%d3 # point to next digit
addq.l &1,%d1 # inc digit counter
dbf.w %d2,ap_p_gd # get next digit
ap_p_fx:
mov.l %d1,%d0 # copy counter to d2
mov.l (%sp),%d1 # get adjusted exp from memory
sub.l %d0,%d1 # subtract count from exp
bge.b ap_p_fm # if still pos, go to pwrten
neg.l %d1 # now its neg; get abs
mov.l (%a0),%d4 # load lword 1 to d4
or.l &0x40000000,%d4 # and set SE in d4
or.l &0x40000000,(%a0) # and in memory
#
# Calculate the mantissa multiplier to compensate for the striping of
# zeros from the mantissa.
#
ap_p_fm:
lea.l PTENRN(%pc),%a1 # get address of power-of-ten table
clr.l %d3 # init table index
fmov.s &0x3f800000,%fp1 # init fp1 to 1
mov.l &3,%d2 # init d2 to count bits in counter
ap_p_el:
asr.l &1,%d0 # shift lsb into carry
bcc.b ap_p_en # if 1, mul fp1 by pwrten factor
fmul.x (%a1,%d3),%fp1 # mul by 10**(d3_bit_no)
ap_p_en:
add.l &12,%d3 # inc d3 to next rtable entry
tst.l %d0 # check if d0 is zero
bne.b ap_p_el # if not, get next bit
fmul.x %fp1,%fp0 # mul mantissa by 10**(no_bits_shifted)
bra.b pwrten # go calc pwrten
#
# This section handles a negative adjusted exponent.
#
ap_st_n:
clr.l %d1 # clr counter
mov.l &2,%d5 # set up d5 to point to lword 3
mov.l (%a0,%d5.L*4),%d4 # get lword 3
bne.b ap_n_cl # if not zero, check digits
sub.l &1,%d5 # dec d5 to point to lword 2
addq.l &8,%d1 # inc counter by 8
mov.l (%a0,%d5.L*4),%d4 # get lword 2
ap_n_cl:
mov.l &28,%d3 # point to last digit
mov.l &7,%d2 # init digit counter
ap_n_gd:
bfextu %d4{%d3:&4},%d0 # get digit
bne.b ap_n_fx # if non-zero, go to exp fix
subq.l &4,%d3 # point to previous digit
addq.l &1,%d1 # inc digit counter
dbf.w %d2,ap_n_gd # get next digit
ap_n_fx:
mov.l %d1,%d0 # copy counter to d0
mov.l (%sp),%d1 # get adjusted exp from memory
sub.l %d0,%d1 # subtract count from exp
bgt.b ap_n_fm # if still pos, go fix mantissa
neg.l %d1 # take abs of exp and clr SE
mov.l (%a0),%d4 # load lword 1 to d4
and.l &0xbfffffff,%d4 # and clr SE in d4
and.l &0xbfffffff,(%a0) # and in memory
#
# Calculate the mantissa multiplier to compensate for the appending of
# zeros to the mantissa.
#
ap_n_fm:
lea.l PTENRN(%pc),%a1 # get address of power-of-ten table
clr.l %d3 # init table index
fmov.s &0x3f800000,%fp1 # init fp1 to 1
mov.l &3,%d2 # init d2 to count bits in counter
ap_n_el:
asr.l &1,%d0 # shift lsb into carry
bcc.b ap_n_en # if 1, mul fp1 by pwrten factor
fmul.x (%a1,%d3),%fp1 # mul by 10**(d3_bit_no)
ap_n_en:
add.l &12,%d3 # inc d3 to next rtable entry
tst.l %d0 # check if d0 is zero
bne.b ap_n_el # if not, get next bit
fdiv.x %fp1,%fp0 # div mantissa by 10**(no_bits_shifted)
#
#
# Calculate power-of-ten factor from adjusted and shifted exponent.
#
# Register usage:
#
# pwrten:
# (*) d0: temp
# ( ) d1: exponent
# (*) d2: {FPCR[6:5],SM,SE} as index in RTABLE; temp
# (*) d3: FPCR work copy
# ( ) d4: first word of bcd
# (*) a1: RTABLE pointer
# calc_p:
# (*) d0: temp
# ( ) d1: exponent
# (*) d3: PWRTxx table index
# ( ) a0: pointer to working copy of bcd
# (*) a1: PWRTxx pointer
# (*) fp1: power-of-ten accumulator
#
# Pwrten calculates the exponent factor in the selected rounding mode
# according to the following table:
#
# Sign of Mant Sign of Exp Rounding Mode PWRTEN Rounding Mode
#
# ANY ANY RN RN
#
# + + RP RP
# - + RP RM
# + - RP RM
# - - RP RP
#
# + + RM RM
# - + RM RP
# + - RM RP
# - - RM RM
#
# + + RZ RM
# - + RZ RM
# + - RZ RP
# - - RZ RP
#
#
pwrten:
mov.l USER_FPCR(%a6),%d3 # get user's FPCR
bfextu %d3{&26:&2},%d2 # isolate rounding mode bits
mov.l (%a0),%d4 # reload 1st bcd word to d4
asl.l &2,%d2 # format d2 to be
bfextu %d4{&0:&2},%d0 # {FPCR[6],FPCR[5],SM,SE}
add.l %d0,%d2 # in d2 as index into RTABLE
lea.l RTABLE(%pc),%a1 # load rtable base
mov.b (%a1,%d2),%d0 # load new rounding bits from table
clr.l %d3 # clear d3 to force no exc and extended
bfins %d0,%d3{&26:&2} # stuff new rounding bits in FPCR
fmov.l %d3,%fpcr # write new FPCR
asr.l &1,%d0 # write correct PTENxx table
bcc.b not_rp # to a1
lea.l PTENRP(%pc),%a1 # it is RP
bra.b calc_p # go to init section
not_rp:
asr.l &1,%d0 # keep checking
bcc.b not_rm
lea.l PTENRM(%pc),%a1 # it is RM
bra.b calc_p # go to init section
not_rm:
lea.l PTENRN(%pc),%a1 # it is RN
calc_p:
mov.l %d1,%d0 # copy exp to d0;use d0
bpl.b no_neg # if exp is negative,
neg.l %d0 # invert it
or.l &0x40000000,(%a0) # and set SE bit
no_neg:
clr.l %d3 # table index
fmov.s &0x3f800000,%fp1 # init fp1 to 1
e_loop:
asr.l &1,%d0 # shift next bit into carry
bcc.b e_next # if zero, skip the mul
fmul.x (%a1,%d3),%fp1 # mul by 10**(d3_bit_no)
e_next:
add.l &12,%d3 # inc d3 to next rtable entry
tst.l %d0 # check if d0 is zero
bne.b e_loop # not zero, continue shifting
#
#
# Check the sign of the adjusted exp and make the value in fp0 the
# same sign. If the exp was pos then multiply fp1*fp0;
# else divide fp0/fp1.
#
# Register Usage:
# norm:
# ( ) a0: pointer to working bcd value
# (*) fp0: mantissa accumulator
# ( ) fp1: scaling factor - 10**(abs(exp))
#
pnorm:
btst &30,(%a0) # test the sign of the exponent
beq.b mul # if clear, go to multiply
div:
fdiv.x %fp1,%fp0 # exp is negative, so divide mant by exp
bra.b end_dec
mul:
fmul.x %fp1,%fp0 # exp is positive, so multiply by exp
#
#
# Clean up and return with result in fp0.
#
# If the final mul/div in decbin incurred an inex exception,
# it will be inex2, but will be reported as inex1 by get_op.
#
end_dec:
fmov.l %fpsr,%d0 # get status register
bclr &inex2_bit+8,%d0 # test for inex2 and clear it
beq.b no_exc # skip this if no exc
ori.w &inx1a_mask,2+USER_FPSR(%a6) # set INEX1/AINEX
no_exc:
add.l &0x4,%sp # clear 1 lw param
fmovm.x (%sp)+,&0x40 # restore fp1
movm.l (%sp)+,&0x3c # restore d2-d5
fmov.l &0x0,%fpcr
fmov.l &0x0,%fpsr
rts
#########################################################################
# bindec(): Converts an input in extended precision format to bcd format#
# #
# INPUT *************************************************************** #
# a0 = pointer to the input extended precision value in memory. #
# the input may be either normalized, unnormalized, or #
# denormalized. #
# d0 = contains the k-factor sign-extended to 32-bits. #
# #
# OUTPUT ************************************************************** #
# FP_SCR0(a6) = bcd format result on the stack. #
# #
# ALGORITHM *********************************************************** #
# #
# A1. Set RM and size ext; Set SIGMA = sign of input. #
# The k-factor is saved for use in d7. Clear the #
# BINDEC_FLG for separating normalized/denormalized #
# input. If input is unnormalized or denormalized, #
# normalize it. #
# #
# A2. Set X = abs(input). #
# #
# A3. Compute ILOG. #
# ILOG is the log base 10 of the input value. It is #
# approximated by adding e + 0.f when the original #
# value is viewed as 2^^e * 1.f in extended precision. #
# This value is stored in d6. #
# #
# A4. Clr INEX bit. #
# The operation in A3 above may have set INEX2. #
# #
# A5. Set ICTR = 0; #
# ICTR is a flag used in A13. It must be set before the #
# loop entry A6. #
# #
# A6. Calculate LEN. #
# LEN is the number of digits to be displayed. The #
# k-factor can dictate either the total number of digits, #
# if it is a positive number, or the number of digits #
# after the decimal point which are to be included as #
# significant. See the 68882 manual for examples. #
# If LEN is computed to be greater than 17, set OPERR in #
# USER_FPSR. LEN is stored in d4. #
# #
# A7. Calculate SCALE. #
# SCALE is equal to 10^ISCALE, where ISCALE is the number #
# of decimal places needed to insure LEN integer digits #
# in the output before conversion to bcd. LAMBDA is the #
# sign of ISCALE, used in A9. Fp1 contains #
# 10^^(abs(ISCALE)) using a rounding mode which is a #
# function of the original rounding mode and the signs #
# of ISCALE and X. A table is given in the code. #
# #
# A8. Clr INEX; Force RZ. #
# The operation in A3 above may have set INEX2. #
# RZ mode is forced for the scaling operation to insure #
# only one rounding error. The grs bits are collected in #
# the INEX flag for use in A10. #
# #
# A9. Scale X -> Y. #
# The mantissa is scaled to the desired number of #
# significant digits. The excess digits are collected #
# in INEX2. #
# #
# A10. Or in INEX. #
# If INEX is set, round error occurred. This is #
# compensated for by 'or-ing' in the INEX2 flag to #
# the lsb of Y. #
# #
# A11. Restore original FPCR; set size ext. #
# Perform FINT operation in the user's rounding mode. #
# Keep the size to extended. #
# #
# A12. Calculate YINT = FINT(Y) according to user's rounding #
# mode. The FPSP routine sintd0 is used. The output #
# is in fp0. #
# #
# A13. Check for LEN digits. #
# If the int operation results in more than LEN digits, #
# or less than LEN -1 digits, adjust ILOG and repeat from #
# A6. This test occurs only on the first pass. If the #
# result is exactly 10^LEN, decrement ILOG and divide #
# the mantissa by 10. #
# #
# A14. Convert the mantissa to bcd. #
# The binstr routine is used to convert the LEN digit #
# mantissa to bcd in memory. The input to binstr is #
# to be a fraction; i.e. (mantissa)/10^LEN and adjusted #
# such that the decimal point is to the left of bit 63. #
# The bcd digits are stored in the correct position in #
# the final string area in memory. #
# #
# A15. Convert the exponent to bcd. #
# As in A14 above, the exp is converted to bcd and the #
# digits are stored in the final string. #
# Test the length of the final exponent string. If the #
# length is 4, set operr. #
# #
# A16. Write sign bits to final string. #
# #
#########################################################################
set BINDEC_FLG, EXC_TEMP # DENORM flag
# Constants in extended precision
PLOG2:
long 0x3FFD0000,0x9A209A84,0xFBCFF798,0x00000000
PLOG2UP1:
long 0x3FFD0000,0x9A209A84,0xFBCFF799,0x00000000
# Constants in single precision
FONE:
long 0x3F800000,0x00000000,0x00000000,0x00000000
FTWO:
long 0x40000000,0x00000000,0x00000000,0x00000000
FTEN:
long 0x41200000,0x00000000,0x00000000,0x00000000
F4933:
long 0x459A2800,0x00000000,0x00000000,0x00000000
# A1. Set RM and size ext. Set SIGMA = sign input;
# The k-factor is saved for use in d7. Clear BINDEC_FLG for
# separating normalized/denormalized input. If the input
# is a denormalized number, set the BINDEC_FLG memory word
# to signal denorm. If the input is unnormalized, normalize
# the input and test for denormalized result.
#
fmov.l &rm_mode*0x10,%fpcr # set RM and ext
mov.l (%a0),L_SCR2(%a6) # save exponent for sign check
mov.l %d0,%d7 # move k-factor to d7
clr.b BINDEC_FLG(%a6) # clr norm/denorm flag
cmpi.b STAG(%a6),&DENORM # is input a DENORM?
bne.w A2_str # no; input is a NORM
#
# Normalize the denorm
#
un_de_norm:
mov.w (%a0),%d0
and.w &0x7fff,%d0 # strip sign of normalized exp
mov.l 4(%a0),%d1
mov.l 8(%a0),%d2
norm_loop:
sub.w &1,%d0
lsl.l &1,%d2
roxl.l &1,%d1
tst.l %d1
bge.b norm_loop
#
# Test if the normalized input is denormalized
#
tst.w %d0
bgt.b pos_exp # if greater than zero, it is a norm
st BINDEC_FLG(%a6) # set flag for denorm
pos_exp:
and.w &0x7fff,%d0 # strip sign of normalized exp
mov.w %d0,(%a0)
mov.l %d1,4(%a0)
mov.l %d2,8(%a0)
# A2. Set X = abs(input).
#
A2_str:
mov.l (%a0),FP_SCR1(%a6) # move input to work space
mov.l 4(%a0),FP_SCR1+4(%a6) # move input to work space
mov.l 8(%a0),FP_SCR1+8(%a6) # move input to work space
and.l &0x7fffffff,FP_SCR1(%a6) # create abs(X)
# A3. Compute ILOG.
# ILOG is the log base 10 of the input value. It is approx-
# imated by adding e + 0.f when the original value is viewed
# as 2^^e * 1.f in extended precision. This value is stored
# in d6.
#
# Register usage:
# Input/Output
# d0: k-factor/exponent
# d2: x/x
# d3: x/x
# d4: x/x
# d5: x/x
# d6: x/ILOG
# d7: k-factor/Unchanged
# a0: ptr for original operand/final result
# a1: x/x
# a2: x/x
# fp0: x/float(ILOG)
# fp1: x/x
# fp2: x/x
# F_SCR1:x/x
# F_SCR2:Abs(X)/Abs(X) with $3fff exponent
# L_SCR1:x/x
# L_SCR2:first word of X packed/Unchanged
tst.b BINDEC_FLG(%a6) # check for denorm
beq.b A3_cont # if clr, continue with norm
mov.l &-4933,%d6 # force ILOG = -4933
bra.b A4_str
A3_cont:
mov.w FP_SCR1(%a6),%d0 # move exp to d0
mov.w &0x3fff,FP_SCR1(%a6) # replace exponent with 0x3fff
fmov.x FP_SCR1(%a6),%fp0 # now fp0 has 1.f
sub.w &0x3fff,%d0 # strip off bias
fadd.w %d0,%fp0 # add in exp
fsub.s FONE(%pc),%fp0 # subtract off 1.0
fbge.w pos_res # if pos, branch
fmul.x PLOG2UP1(%pc),%fp0 # if neg, mul by LOG2UP1
fmov.l %fp0,%d6 # put ILOG in d6 as a lword
bra.b A4_str # go move out ILOG
pos_res:
fmul.x PLOG2(%pc),%fp0 # if pos, mul by LOG2
fmov.l %fp0,%d6 # put ILOG in d6 as a lword
# A4. Clr INEX bit.
# The operation in A3 above may have set INEX2.
A4_str:
fmov.l &0,%fpsr # zero all of fpsr - nothing needed
# A5. Set ICTR = 0;
# ICTR is a flag used in A13. It must be set before the
# loop entry A6. The lower word of d5 is used for ICTR.
clr.w %d5 # clear ICTR
# A6. Calculate LEN.
# LEN is the number of digits to be displayed. The k-factor
# can dictate either the total number of digits, if it is
# a positive number, or the number of digits after the
# original decimal point which are to be included as
# significant. See the 68882 manual for examples.
# If LEN is computed to be greater than 17, set OPERR in
# USER_FPSR. LEN is stored in d4.
#
# Register usage:
# Input/Output
# d0: exponent/Unchanged
# d2: x/x/scratch
# d3: x/x
# d4: exc picture/LEN
# d5: ICTR/Unchanged
# d6: ILOG/Unchanged
# d7: k-factor/Unchanged
# a0: ptr for original operand/final result
# a1: x/x
# a2: x/x
# fp0: float(ILOG)/Unchanged
# fp1: x/x
# fp2: x/x
# F_SCR1:x/x
# F_SCR2:Abs(X) with $3fff exponent/Unchanged
# L_SCR1:x/x
# L_SCR2:first word of X packed/Unchanged
A6_str:
tst.l %d7 # branch on sign of k
ble.b k_neg # if k <= 0, LEN = ILOG + 1 - k
mov.l %d7,%d4 # if k > 0, LEN = k
bra.b len_ck # skip to LEN check
k_neg:
mov.l %d6,%d4 # first load ILOG to d4
sub.l %d7,%d4 # subtract off k
addq.l &1,%d4 # add in the 1
len_ck:
tst.l %d4 # LEN check: branch on sign of LEN
ble.b LEN_ng # if neg, set LEN = 1
cmp.l %d4,&17 # test if LEN > 17
ble.b A7_str # if not, forget it
mov.l &17,%d4 # set max LEN = 17
tst.l %d7 # if negative, never set OPERR
ble.b A7_str # if positive, continue
or.l &opaop_mask,USER_FPSR(%a6) # set OPERR & AIOP in USER_FPSR
bra.b A7_str # finished here
LEN_ng:
mov.l &1,%d4 # min LEN is 1
# A7. Calculate SCALE.
# SCALE is equal to 10^ISCALE, where ISCALE is the number
# of decimal places needed to insure LEN integer digits
# in the output before conversion to bcd. LAMBDA is the sign
# of ISCALE, used in A9. Fp1 contains 10^^(abs(ISCALE)) using
# the rounding mode as given in the following table (see
# Coonen, p. 7.23 as ref.; however, the SCALE variable is
# of opposite sign in bindec.sa from Coonen).
#
# Initial USE
# FPCR[6:5] LAMBDA SIGN(X) FPCR[6:5]
# ----------------------------------------------
# RN 00 0 0 00/0 RN
# RN 00 0 1 00/0 RN
# RN 00 1 0 00/0 RN
# RN 00 1 1 00/0 RN
# RZ 01 0 0 11/3 RP
# RZ 01 0 1 11/3 RP
# RZ 01 1 0 10/2 RM
# RZ 01 1 1 10/2 RM
# RM 10 0 0 11/3 RP
# RM 10 0 1 10/2 RM
# RM 10 1 0 10/2 RM
# RM 10 1 1 11/3 RP
# RP 11 0 0 10/2 RM
# RP 11 0 1 11/3 RP
# RP 11 1 0 11/3 RP
# RP 11 1 1 10/2 RM
#
# Register usage:
# Input/Output
# d0: exponent/scratch - final is 0
# d2: x/0 or 24 for A9
# d3: x/scratch - offset ptr into PTENRM array
# d4: LEN/Unchanged
# d5: 0/ICTR:LAMBDA
# d6: ILOG/ILOG or k if ((k<=0)&(ILOG<k))
# d7: k-factor/Unchanged
# a0: ptr for original operand/final result
# a1: x/ptr to PTENRM array
# a2: x/x
# fp0: float(ILOG)/Unchanged
# fp1: x/10^ISCALE
# fp2: x/x
# F_SCR1:x/x
# F_SCR2:Abs(X) with $3fff exponent/Unchanged
# L_SCR1:x/x
# L_SCR2:first word of X packed/Unchanged
A7_str:
tst.l %d7 # test sign of k
bgt.b k_pos # if pos and > 0, skip this
cmp.l %d7,%d6 # test k - ILOG
blt.b k_pos # if ILOG >= k, skip this
mov.l %d7,%d6 # if ((k<0) & (ILOG < k)) ILOG = k
k_pos:
mov.l %d6,%d0 # calc ILOG + 1 - LEN in d0
addq.l &1,%d0 # add the 1
sub.l %d4,%d0 # sub off LEN
swap %d5 # use upper word of d5 for LAMBDA
clr.w %d5 # set it zero initially
clr.w %d2 # set up d2 for very small case
tst.l %d0 # test sign of ISCALE
bge.b iscale # if pos, skip next inst
addq.w &1,%d5 # if neg, set LAMBDA true
cmp.l %d0,&0xffffecd4 # test iscale <= -4908
bgt.b no_inf # if false, skip rest
add.l &24,%d0 # add in 24 to iscale
mov.l &24,%d2 # put 24 in d2 for A9
no_inf:
neg.l %d0 # and take abs of ISCALE
iscale:
fmov.s FONE(%pc),%fp1 # init fp1 to 1
bfextu USER_FPCR(%a6){&26:&2},%d1 # get initial rmode bits
lsl.w &1,%d1 # put them in bits 2:1
add.w %d5,%d1 # add in LAMBDA
lsl.w &1,%d1 # put them in bits 3:1
tst.l L_SCR2(%a6) # test sign of original x
bge.b x_pos # if pos, don't set bit 0
addq.l &1,%d1 # if neg, set bit 0
x_pos:
lea.l RBDTBL(%pc),%a2 # load rbdtbl base
mov.b (%a2,%d1),%d3 # load d3 with new rmode
lsl.l &4,%d3 # put bits in proper position
fmov.l %d3,%fpcr # load bits into fpu
lsr.l &4,%d3 # put bits in proper position
tst.b %d3 # decode new rmode for pten table
bne.b not_rn # if zero, it is RN
lea.l PTENRN(%pc),%a1 # load a1 with RN table base
bra.b rmode # exit decode
not_rn:
lsr.b &1,%d3 # get lsb in carry
bcc.b not_rp2 # if carry clear, it is RM
lea.l PTENRP(%pc),%a1 # load a1 with RP table base
bra.b rmode # exit decode
not_rp2:
lea.l PTENRM(%pc),%a1 # load a1 with RM table base
rmode:
clr.l %d3 # clr table index
e_loop2:
lsr.l &1,%d0 # shift next bit into carry
bcc.b e_next2 # if zero, skip the mul
fmul.x (%a1,%d3),%fp1 # mul by 10**(d3_bit_no)
e_next2:
add.l &12,%d3 # inc d3 to next pwrten table entry
tst.l %d0 # test if ISCALE is zero
bne.b e_loop2 # if not, loop
# A8. Clr INEX; Force RZ.
# The operation in A3 above may have set INEX2.
# RZ mode is forced for the scaling operation to insure
# only one rounding error. The grs bits are collected in
# the INEX flag for use in A10.
#
# Register usage:
# Input/Output
# A9. Scale X -> Y.
# The mantissa is scaled to the desired number of significant
# digits. The excess digits are collected in INEX2. If mul,
# Check d2 for excess 10 exponential value. If not zero,
# the iscale value would have caused the pwrten calculation
# to overflow. Only a negative iscale can cause this, so
# multiply by 10^(d2), which is now only allowed to be 24,
# with a multiply by 10^8 and 10^16, which is exact since
# 10^24 is exact. If the input was denormalized, we must
# create a busy stack frame with the mul command and the
# two operands, and allow the fpu to complete the multiply.
#
# Register usage:
# Input/Output
# d0: FPCR with RZ mode/Unchanged
# d2: 0 or 24/unchanged
# d3: x/x
# d4: LEN/Unchanged
# d5: ICTR:LAMBDA
# d6: ILOG/Unchanged
# d7: k-factor/Unchanged
# a0: ptr for original operand/final result
# a1: ptr to PTENRM array/Unchanged
# a2: x/x
# fp0: float(ILOG)/X adjusted for SCALE (Y)
# fp1: 10^ISCALE/Unchanged
# fp2: x/x
# F_SCR1:x/x
# F_SCR2:Abs(X) with $3fff exponent/Unchanged
# L_SCR1:x/x
# L_SCR2:first word of X packed/Unchanged
A9_str:
fmov.x (%a0),%fp0 # load X from memory
fabs.x %fp0 # use abs(X)
tst.w %d5 # LAMBDA is in lower word of d5
bne.b sc_mul # if neg (LAMBDA = 1), scale by mul
fdiv.x %fp1,%fp0 # calculate X / SCALE -> Y to fp0
bra.w A10_st # branch to A10
sc_mul:
tst.b BINDEC_FLG(%a6) # check for denorm
beq.w A9_norm # if norm, continue with mul
# for DENORM, we must calculate:
# fp0 = input_op * 10^ISCALE * 10^24
# since the input operand is a DENORM, we can't multiply it directly.
# so, we do the multiplication of the exponents and mantissas separately.
# in this way, we avoid underflow on intermediate stages of the
# multiplication and guarantee a result without exception.
fmovm.x &0x2,-(%sp) # save 10^ISCALE to stack
andi.w &0x8000,(%sp) # keep sign
or.w %d3,(%sp) # insert new exponent
andi.w &0x7fff,(%a0) # clear sign bit on DENORM again
mov.l 0x8(%a0),-(%sp) # put input op mantissa on stk
mov.l 0x4(%a0),-(%sp)
mov.l &0x3fff0000,-(%sp) # force exp to zero
fmovm.x (%sp)+,&0x80 # load normalized DENORM into fp0
fmul.x (%sp)+,%fp0
# fmul.x 36(%a1),%fp0 # multiply fp0 by 10^8
# fmul.x 48(%a1),%fp0 # multiply fp0 by 10^16
mov.l 36+8(%a1),-(%sp) # get 10^8 mantissa
mov.l 36+4(%a1),-(%sp)
mov.l &0x3fff0000,-(%sp) # force exp to zero
mov.l 48+8(%a1),-(%sp) # get 10^16 mantissa
mov.l 48+4(%a1),-(%sp)
mov.l &0x3fff0000,-(%sp)# force exp to zero
fmul.x (%sp)+,%fp0 # multiply fp0 by 10^8
fmul.x (%sp)+,%fp0 # multiply fp0 by 10^16
bra.b A10_st
sc_mul_err:
bra.b sc_mul_err
A9_norm:
tst.w %d2 # test for small exp case
beq.b A9_con # if zero, continue as normal
fmul.x 36(%a1),%fp0 # multiply fp0 by 10^8
fmul.x 48(%a1),%fp0 # multiply fp0 by 10^16
A9_con:
fmul.x %fp1,%fp0 # calculate X * SCALE -> Y to fp0
# A10. Or in INEX.
# If INEX is set, round error occurred. This is compensated
# for by 'or-ing' in the INEX2 flag to the lsb of Y.
#
# Register usage:
# Input/Output
# d0: FPCR with RZ mode/FPSR with INEX2 isolated
# d2: x/x
# d3: x/x
# d4: LEN/Unchanged
# d5: ICTR:LAMBDA
# d6: ILOG/Unchanged
# d7: k-factor/Unchanged
# a0: ptr for original operand/final result
# a1: ptr to PTENxx array/Unchanged
# a2: x/ptr to FP_SCR1(a6)
# fp0: Y/Y with lsb adjusted
# fp1: 10^ISCALE/Unchanged
# fp2: x/x
A10_st:
fmov.l %fpsr,%d0 # get FPSR
fmov.x %fp0,FP_SCR1(%a6) # move Y to memory
lea.l FP_SCR1(%a6),%a2 # load a2 with ptr to FP_SCR1
btst &9,%d0 # check if INEX2 set
beq.b A11_st # if clear, skip rest
or.l &1,8(%a2) # or in 1 to lsb of mantissa
fmov.x FP_SCR1(%a6),%fp0 # write adjusted Y back to fpu
# A11. Restore original FPCR; set size ext.
# Perform FINT operation in the user's rounding mode. Keep
# the size to extended. The sintdo entry point in the sint
# routine expects the FPCR value to be in USER_FPCR for
# mode and precision. The original FPCR is saved in L_SCR1.
A11_st:
mov.l USER_FPCR(%a6),L_SCR1(%a6) # save it for later
and.l &0x00000030,USER_FPCR(%a6) # set size to ext,
# ;block exceptions
# A12. Calculate YINT = FINT(Y) according to user's rounding mode.
# The FPSP routine sintd0 is used. The output is in fp0.
#
# Register usage:
# Input/Output
# d0: FPSR with AINEX cleared/FPCR with size set to ext
# d2: x/x/scratch
# d3: x/x
# d4: LEN/Unchanged
# d5: ICTR:LAMBDA/Unchanged
# d6: ILOG/Unchanged
# d7: k-factor/Unchanged
# a0: ptr for original operand/src ptr for sintdo
# a1: ptr to PTENxx array/Unchanged
# a2: ptr to FP_SCR1(a6)/Unchanged
# a6: temp pointer to FP_SCR1(a6) - orig value saved and restored
# fp0: Y/YINT
# fp1: 10^ISCALE/Unchanged
# fp2: x/x
# F_SCR1:x/x
# F_SCR2:Y adjusted for inex/Y with original exponent
# L_SCR1:x/original USER_FPCR
# L_SCR2:first word of X packed/Unchanged
A12_st:
movm.l &0xc0c0,-(%sp) # save regs used by sintd0 {%d0-%d1/%a0-%a1}
mov.l L_SCR1(%a6),-(%sp)
mov.l L_SCR2(%a6),-(%sp)
lea.l FP_SCR1(%a6),%a0 # a0 is ptr to FP_SCR1(a6)
fmov.x %fp0,(%a0) # move Y to memory at FP_SCR1(a6)
tst.l L_SCR2(%a6) # test sign of original operand
bge.b do_fint12 # if pos, use Y
or.l &0x80000000,(%a0) # if neg, use -Y
do_fint12:
mov.l USER_FPSR(%a6),-(%sp)
# bsr sintdo # sint routine returns int in fp0
# A13. Check for LEN digits.
# If the int operation results in more than LEN digits,
# or less than LEN -1 digits, adjust ILOG and repeat from
# A6. This test occurs only on the first pass. If the
# result is exactly 10^LEN, decrement ILOG and divide
# the mantissa by 10. The calculation of 10^LEN cannot
# be inexact, since all powers of ten upto 10^27 are exact
# in extended precision, so the use of a previous power-of-ten
# table will introduce no error.
#
#
# Register usage:
# Input/Output
# d0: FPCR with size set to ext/scratch final = 0
# d2: x/x
# d3: x/scratch final = x
# d4: LEN/LEN adjusted
# d5: ICTR:LAMBDA/LAMBDA:ICTR
# d6: ILOG/ILOG adjusted
# d7: k-factor/Unchanged
# a0: pointer into memory for packed bcd string formation
# a1: ptr to PTENxx array/Unchanged
# a2: ptr to FP_SCR1(a6)/Unchanged
# fp0: int portion of Y/abs(YINT) adjusted
# fp1: 10^ISCALE/Unchanged
# fp2: x/10^LEN
# F_SCR1:x/x
# F_SCR2:Y with original exponent/Unchanged
# L_SCR1:original USER_FPCR/Unchanged
# L_SCR2:first word of X packed/Unchanged
A13_st:
swap %d5 # put ICTR in lower word of d5
tst.w %d5 # check if ICTR = 0
bne not_zr # if non-zero, go to second test
#
# Compute 10^(LEN-1)
#
fmov.s FONE(%pc),%fp2 # init fp2 to 1.0
mov.l %d4,%d0 # put LEN in d0
subq.l &1,%d0 # d0 = LEN -1
clr.l %d3 # clr table index
l_loop:
lsr.l &1,%d0 # shift next bit into carry
bcc.b l_next # if zero, skip the mul
fmul.x (%a1,%d3),%fp2 # mul by 10**(d3_bit_no)
l_next:
add.l &12,%d3 # inc d3 to next pwrten table entry
tst.l %d0 # test if LEN is zero
bne.b l_loop # if not, loop
#
# 10^LEN-1 is computed for this test and A14. If the input was
# denormalized, check only the case in which YINT > 10^LEN.
#
tst.b BINDEC_FLG(%a6) # check if input was norm
beq.b A13_con # if norm, continue with checking
fabs.x %fp0 # take abs of YINT
bra test_2
#
# Compare abs(YINT) to 10^(LEN-1) and 10^LEN
#
A13_con:
fabs.x %fp0 # take abs of YINT
fcmp.x %fp0,%fp2 # compare abs(YINT) with 10^(LEN-1)
fbge.w test_2 # if greater, do next test
subq.l &1,%d6 # subtract 1 from ILOG
mov.w &1,%d5 # set ICTR
fmov.l &rm_mode*0x10,%fpcr # set rmode to RM
fmul.s FTEN(%pc),%fp2 # compute 10^LEN
bra.w A6_str # return to A6 and recompute YINT
test_2:
fmul.s FTEN(%pc),%fp2 # compute 10^LEN
fcmp.x %fp0,%fp2 # compare abs(YINT) with 10^LEN
fblt.w A14_st # if less, all is ok, go to A14
fbgt.w fix_ex # if greater, fix and redo
fdiv.s FTEN(%pc),%fp0 # if equal, divide by 10
addq.l &1,%d6 # and inc ILOG
bra.b A14_st # and continue elsewhere
fix_ex:
addq.l &1,%d6 # increment ILOG by 1
mov.w &1,%d5 # set ICTR
fmov.l &rm_mode*0x10,%fpcr # set rmode to RM
bra.w A6_str # return to A6 and recompute YINT
#
# Since ICTR <> 0, we have already been through one adjustment,
# and shouldn't have another; this is to check if abs(YINT) = 10^LEN
# 10^LEN is again computed using whatever table is in a1 since the
# value calculated cannot be inexact.
#
not_zr:
fmov.s FONE(%pc),%fp2 # init fp2 to 1.0
mov.l %d4,%d0 # put LEN in d0
clr.l %d3 # clr table index
z_loop:
lsr.l &1,%d0 # shift next bit into carry
bcc.b z_next # if zero, skip the mul
fmul.x (%a1,%d3),%fp2 # mul by 10**(d3_bit_no)
z_next:
add.l &12,%d3 # inc d3 to next pwrten table entry
tst.l %d0 # test if LEN is zero
bne.b z_loop # if not, loop
fabs.x %fp0 # get abs(YINT)
fcmp.x %fp0,%fp2 # check if abs(YINT) = 10^LEN
fbneq.w A14_st # if not, skip this
fdiv.s FTEN(%pc),%fp0 # divide abs(YINT) by 10
addq.l &1,%d6 # and inc ILOG by 1
addq.l &1,%d4 # and inc LEN
fmul.s FTEN(%pc),%fp2 # if LEN++, the get 10^^LEN
# A14. Convert the mantissa to bcd.
# The binstr routine is used to convert the LEN digit
# mantissa to bcd in memory. The input to binstr is
# to be a fraction; i.e. (mantissa)/10^LEN and adjusted
# such that the decimal point is to the left of bit 63.
# The bcd digits are stored in the correct position in
# the final string area in memory.
#
#
# Register usage:
# Input/Output
# d0: x/LEN call to binstr - final is 0
# d1: x/0
# d2: x/ms 32-bits of mant of abs(YINT)
# d3: x/ls 32-bits of mant of abs(YINT)
# d4: LEN/Unchanged
# d5: ICTR:LAMBDA/LAMBDA:ICTR
# d6: ILOG
# d7: k-factor/Unchanged
# a0: pointer into memory for packed bcd string formation
# /ptr to first mantissa byte in result string
# a1: ptr to PTENxx array/Unchanged
# a2: ptr to FP_SCR1(a6)/Unchanged
# fp0: int portion of Y/abs(YINT) adjusted
# fp1: 10^ISCALE/Unchanged
# fp2: 10^LEN/Unchanged
# F_SCR1:x/Work area for final result
# F_SCR2:Y with original exponent/Unchanged
# L_SCR1:original USER_FPCR/Unchanged
# L_SCR2:first word of X packed/Unchanged
A14_st:
fmov.l &rz_mode*0x10,%fpcr # force rz for conversion
fdiv.x %fp2,%fp0 # divide abs(YINT) by 10^LEN
lea.l FP_SCR0(%a6),%a0
fmov.x %fp0,(%a0) # move abs(YINT)/10^LEN to memory
mov.l 4(%a0),%d2 # move 2nd word of FP_RES to d2
mov.l 8(%a0),%d3 # move 3rd word of FP_RES to d3
clr.l 4(%a0) # zero word 2 of FP_RES
clr.l 8(%a0) # zero word 3 of FP_RES
mov.l (%a0),%d0 # move exponent to d0
swap %d0 # put exponent in lower word
beq.b no_sft # if zero, don't shift
sub.l &0x3ffd,%d0 # sub bias less 2 to make fract
tst.l %d0 # check if > 1
bgt.b no_sft # if so, don't shift
neg.l %d0 # make exp positive
m_loop:
lsr.l &1,%d2 # shift d2:d3 right, add 0s
roxr.l &1,%d3 # the number of places
dbf.w %d0,m_loop # given in d0
no_sft:
tst.l %d2 # check for mantissa of zero
bne.b no_zr # if not, go on
tst.l %d3 # continue zero check
beq.b zer_m # if zero, go directly to binstr
no_zr:
clr.l %d1 # put zero in d1 for addx
add.l &0x00000080,%d3 # inc at bit 7
addx.l %d1,%d2 # continue inc
and.l &0xffffff80,%d3 # strip off lsb not used by 882
zer_m:
mov.l %d4,%d0 # put LEN in d0 for binstr call
addq.l &3,%a0 # a0 points to M16 byte in result
bsr binstr # call binstr to convert mant
# A15. Convert the exponent to bcd.
# As in A14 above, the exp is converted to bcd and the
# digits are stored in the final string.
#
# Digits are stored in L_SCR1(a6) on return from BINDEC as:
#
# 32 16 15 0
# -----------------------------------------
# | 0 | e3 | e2 | e1 | e4 | X | X | X |
# -----------------------------------------
#
# And are moved into their proper places in FP_SCR0. If digit e4
# is non-zero, OPERR is signaled. In all cases, all 4 digits are
# written as specified in the 881/882 manual for packed decimal.
#
# Register usage:
# Input/Output
# d0: x/LEN call to binstr - final is 0
# d1: x/scratch (0);shift count for final exponent packing
# d2: x/ms 32-bits of exp fraction/scratch
# d3: x/ls 32-bits of exp fraction
# d4: LEN/Unchanged
# d5: ICTR:LAMBDA/LAMBDA:ICTR
# d6: ILOG
# d7: k-factor/Unchanged
# a0: ptr to result string/ptr to L_SCR1(a6)
# a1: ptr to PTENxx array/Unchanged
# a2: ptr to FP_SCR1(a6)/Unchanged
# fp0: abs(YINT) adjusted/float(ILOG)
# fp1: 10^ISCALE/Unchanged
# fp2: 10^LEN/Unchanged
# F_SCR1:Work area for final result/BCD result
# F_SCR2:Y with original exponent/ILOG/10^4
# L_SCR1:original USER_FPCR/Exponent digits on return from binstr
# L_SCR2:first word of X packed/Unchanged
A15_st:
tst.b BINDEC_FLG(%a6) # check for denorm
beq.b not_denorm
ftest.x %fp0 # test for zero
fbeq.w den_zero # if zero, use k-factor or 4933
fmov.l %d6,%fp0 # float ILOG
fabs.x %fp0 # get abs of ILOG
bra.b convrt
den_zero:
tst.l %d7 # check sign of the k-factor
blt.b use_ilog # if negative, use ILOG
fmov.s F4933(%pc),%fp0 # force exponent to 4933
bra.b convrt # do it
use_ilog:
fmov.l %d6,%fp0 # float ILOG
fabs.x %fp0 # get abs of ILOG
bra.b convrt
not_denorm:
ftest.x %fp0 # test for zero
fbneq.w not_zero # if zero, force exponent
fmov.s FONE(%pc),%fp0 # force exponent to 1
bra.b convrt # do it
not_zero:
fmov.l %d6,%fp0 # float ILOG
fabs.x %fp0 # get abs of ILOG
convrt:
fdiv.x 24(%a1),%fp0 # compute ILOG/10^4
fmov.x %fp0,FP_SCR1(%a6) # store fp0 in memory
mov.l 4(%a2),%d2 # move word 2 to d2
mov.l 8(%a2),%d3 # move word 3 to d3
mov.w (%a2),%d0 # move exp to d0
beq.b x_loop_fin # if zero, skip the shift
sub.w &0x3ffd,%d0 # subtract off bias
neg.w %d0 # make exp positive
x_loop:
lsr.l &1,%d2 # shift d2:d3 right
roxr.l &1,%d3 # the number of places
dbf.w %d0,x_loop # given in d0
x_loop_fin:
clr.l %d1 # put zero in d1 for addx
add.l &0x00000080,%d3 # inc at bit 6
addx.l %d1,%d2 # continue inc
and.l &0xffffff80,%d3 # strip off lsb not used by 882
mov.l &4,%d0 # put 4 in d0 for binstr call
lea.l L_SCR1(%a6),%a0 # a0 is ptr to L_SCR1 for exp digits
bsr binstr # call binstr to convert exp
mov.l L_SCR1(%a6),%d0 # load L_SCR1 lword to d0
mov.l &12,%d1 # use d1 for shift count
lsr.l %d1,%d0 # shift d0 right by 12
bfins %d0,FP_SCR0(%a6){&4:&12} # put e3:e2:e1 in FP_SCR0
lsr.l %d1,%d0 # shift d0 right by 12
bfins %d0,FP_SCR0(%a6){&16:&4} # put e4 in FP_SCR0
tst.b %d0 # check if e4 is zero
beq.b A16_st # if zero, skip rest
or.l &opaop_mask,USER_FPSR(%a6) # set OPERR & AIOP in USER_FPSR
# A16. Write sign bits to final string.
# Sigma is bit 31 of initial value; RHO is bit 31 of d6 (ILOG).
#
# Register usage:
# Input/Output
# d0: x/scratch - final is x
# d2: x/x
# d3: x/x
# d4: LEN/Unchanged
# d5: ICTR:LAMBDA/LAMBDA:ICTR
# d6: ILOG/ILOG adjusted
# d7: k-factor/Unchanged
# a0: ptr to L_SCR1(a6)/Unchanged
# a1: ptr to PTENxx array/Unchanged
# a2: ptr to FP_SCR1(a6)/Unchanged
# fp0: float(ILOG)/Unchanged
# fp1: 10^ISCALE/Unchanged
# fp2: 10^LEN/Unchanged
# F_SCR1:BCD result with correct signs
# F_SCR2:ILOG/10^4
# L_SCR1:Exponent digits on return from binstr
# L_SCR2:first word of X packed/Unchanged
A16_st:
clr.l %d0 # clr d0 for collection of signs
and.b &0x0f,FP_SCR0(%a6) # clear first nibble of FP_SCR0
tst.l L_SCR2(%a6) # check sign of original mantissa
bge.b mant_p # if pos, don't set SM
mov.l &2,%d0 # move 2 in to d0 for SM
mant_p:
tst.l %d6 # check sign of ILOG
bge.b wr_sgn # if pos, don't set SE
addq.l &1,%d0 # set bit 0 in d0 for SE
wr_sgn:
bfins %d0,FP_SCR0(%a6){&0:&2} # insert SM and SE into FP_SCR0
global PTENRN
PTENRN:
long 0x40020000,0xA0000000,0x00000000 # 10 ^ 1
long 0x40050000,0xC8000000,0x00000000 # 10 ^ 2
long 0x400C0000,0x9C400000,0x00000000 # 10 ^ 4
long 0x40190000,0xBEBC2000,0x00000000 # 10 ^ 8
long 0x40340000,0x8E1BC9BF,0x04000000 # 10 ^ 16
long 0x40690000,0x9DC5ADA8,0x2B70B59E # 10 ^ 32
long 0x40D30000,0xC2781F49,0xFFCFA6D5 # 10 ^ 64
long 0x41A80000,0x93BA47C9,0x80E98CE0 # 10 ^ 128
long 0x43510000,0xAA7EEBFB,0x9DF9DE8E # 10 ^ 256
long 0x46A30000,0xE319A0AE,0xA60E91C7 # 10 ^ 512
long 0x4D480000,0xC9767586,0x81750C17 # 10 ^ 1024
long 0x5A920000,0x9E8B3B5D,0xC53D5DE5 # 10 ^ 2048
long 0x75250000,0xC4605202,0x8A20979B # 10 ^ 4096
global PTENRP
PTENRP:
long 0x40020000,0xA0000000,0x00000000 # 10 ^ 1
long 0x40050000,0xC8000000,0x00000000 # 10 ^ 2
long 0x400C0000,0x9C400000,0x00000000 # 10 ^ 4
long 0x40190000,0xBEBC2000,0x00000000 # 10 ^ 8
long 0x40340000,0x8E1BC9BF,0x04000000 # 10 ^ 16
long 0x40690000,0x9DC5ADA8,0x2B70B59E # 10 ^ 32
long 0x40D30000,0xC2781F49,0xFFCFA6D6 # 10 ^ 64
long 0x41A80000,0x93BA47C9,0x80E98CE0 # 10 ^ 128
long 0x43510000,0xAA7EEBFB,0x9DF9DE8E # 10 ^ 256
long 0x46A30000,0xE319A0AE,0xA60E91C7 # 10 ^ 512
long 0x4D480000,0xC9767586,0x81750C18 # 10 ^ 1024
long 0x5A920000,0x9E8B3B5D,0xC53D5DE5 # 10 ^ 2048
long 0x75250000,0xC4605202,0x8A20979B # 10 ^ 4096
global PTENRM
PTENRM:
long 0x40020000,0xA0000000,0x00000000 # 10 ^ 1
long 0x40050000,0xC8000000,0x00000000 # 10 ^ 2
long 0x400C0000,0x9C400000,0x00000000 # 10 ^ 4
long 0x40190000,0xBEBC2000,0x00000000 # 10 ^ 8
long 0x40340000,0x8E1BC9BF,0x04000000 # 10 ^ 16
long 0x40690000,0x9DC5ADA8,0x2B70B59D # 10 ^ 32
long 0x40D30000,0xC2781F49,0xFFCFA6D5 # 10 ^ 64
long 0x41A80000,0x93BA47C9,0x80E98CDF # 10 ^ 128
long 0x43510000,0xAA7EEBFB,0x9DF9DE8D # 10 ^ 256
long 0x46A30000,0xE319A0AE,0xA60E91C6 # 10 ^ 512
long 0x4D480000,0xC9767586,0x81750C17 # 10 ^ 1024
long 0x5A920000,0x9E8B3B5D,0xC53D5DE4 # 10 ^ 2048
long 0x75250000,0xC4605202,0x8A20979A # 10 ^ 4096
#########################################################################
# binstr(): Converts a 64-bit binary integer to bcd. #
# #
# INPUT *************************************************************** #
# d2:d3 = 64-bit binary integer #
# d0 = desired length (LEN) #
# a0 = pointer to start in memory for bcd characters #
# (This pointer must point to byte 4 of the first #
# lword of the packed decimal memory string.) #
# #
# OUTPUT ************************************************************** #
# a0 = pointer to LEN bcd digits representing the 64-bit integer. #
# #
# ALGORITHM *********************************************************** #
# The 64-bit binary is assumed to have a decimal point before #
# bit 63. The fraction is multiplied by 10 using a mul by 2 #
# shift and a mul by 8 shift. The bits shifted out of the #
# msb form a decimal digit. This process is iterated until #
# LEN digits are formed. #
# #
# A1. Init d7 to 1. D7 is the byte digit counter, and if 1, the #
# digit formed will be assumed the least significant. This is #
# to force the first byte formed to have a 0 in the upper 4 bits. #
# #
# A2. Beginning of the loop: #
# Copy the fraction in d2:d3 to d4:d5. #
# #
# A3. Multiply the fraction in d2:d3 by 8 using bit-field #
# extracts and shifts. The three msbs from d2 will go into d1. #
# #
# A4. Multiply the fraction in d4:d5 by 2 using shifts. The msb #
# will be collected by the carry. #
# #
# A5. Add using the carry the 64-bit quantities in d2:d3 and d4:d5 #
# into d2:d3. D1 will contain the bcd digit formed. #
# #
# A6. Test d7. If zero, the digit formed is the ms digit. If non- #
# zero, it is the ls digit. Put the digit in its place in the #
# upper word of d0. If it is the ls digit, write the word #
# from d0 to memory. #
# #
# A7. Decrement d6 (LEN counter) and repeat the loop until zero. #
# #
#########################################################################
# Implementation Notes:
#
# The registers are used as follows:
#
# d0: LEN counter
# d1: temp used to form the digit
# d2: upper 32-bits of fraction for mul by 8
# d3: lower 32-bits of fraction for mul by 8
# d4: upper 32-bits of fraction for mul by 2
# d5: lower 32-bits of fraction for mul by 2
# d6: temp for bit-field extracts
# d7: byte digit formation word;digit count {0,1}
# a0: pointer into memory for packed bcd string formation
#
global binstr
binstr:
movm.l &0xff00,-(%sp) # {%d0-%d7}
#
# A1: Init d7
#
mov.l &1,%d7 # init d7 for second digit
subq.l &1,%d0 # for dbf d0 would have LEN+1 passes
#
# A2. Copy d2:d3 to d4:d5. Start loop.
#
loop:
mov.l %d2,%d4 # copy the fraction before muls
mov.l %d3,%d5 # to d4:d5
#
# A3. Multiply d2:d3 by 8; extract msbs into d1.
#
bfextu %d2{&0:&3},%d1 # copy 3 msbs of d2 into d1
asl.l &3,%d2 # shift d2 left by 3 places
bfextu %d3{&0:&3},%d6 # copy 3 msbs of d3 into d6
asl.l &3,%d3 # shift d3 left by 3 places
or.l %d6,%d2 # or in msbs from d3 into d2
#
# A4. Multiply d4:d5 by 2; add carry out to d1.
#
asl.l &1,%d5 # mul d5 by 2
roxl.l &1,%d4 # mul d4 by 2
swap %d6 # put 0 in d6 lower word
addx.w %d6,%d1 # add in extend from mul by 2
#
# A5. Add mul by 8 to mul by 2. D1 contains the digit formed.
#
add.l %d5,%d3 # add lower 32 bits
nop # ERRATA FIX #13 (Rev. 1.2 6/6/90)
addx.l %d4,%d2 # add with extend upper 32 bits
nop # ERRATA FIX #13 (Rev. 1.2 6/6/90)
addx.w %d6,%d1 # add in extend from add to d1
swap %d6 # with d6 = 0; put 0 in upper word
#
# A6. Test d7 and branch.
#
tst.w %d7 # if zero, store digit & to loop
beq.b first_d # if non-zero, form byte & write
sec_d:
swap %d7 # bring first digit to word d7b
asl.w &4,%d7 # first digit in upper 4 bits d7b
add.w %d1,%d7 # add in ls digit to d7b
mov.b %d7,(%a0)+ # store d7b byte in memory
swap %d7 # put LEN counter in word d7a
clr.w %d7 # set d7a to signal no digits done
dbf.w %d0,loop # do loop some more!
bra.b end_bstr # finished, so exit
first_d:
swap %d7 # put digit word in d7b
mov.w %d1,%d7 # put new digit in d7b
swap %d7 # put LEN counter in word d7a
addq.w &1,%d7 # set d7a to signal first digit done
dbf.w %d0,loop # do loop some more!
swap %d7 # put last digit in string
lsl.w &4,%d7 # move it to upper 4 bits
mov.b %d7,(%a0)+ # store it in memory string
#
# Clean up and return with result in fp0.
#
end_bstr:
movm.l (%sp)+,&0xff # {%d0-%d7}
rts
#########################################################################
# XDEF **************************************************************** #
# facc_in_b(): dmem_read_byte failed #
# facc_in_w(): dmem_read_word failed #
# facc_in_l(): dmem_read_long failed #
# facc_in_d(): dmem_read of dbl prec failed #
# facc_in_x(): dmem_read of ext prec failed #
# #
# facc_out_b(): dmem_write_byte failed #
# facc_out_w(): dmem_write_word failed #
# facc_out_l(): dmem_write_long failed #
# facc_out_d(): dmem_write of dbl prec failed #
# facc_out_x(): dmem_write of ext prec failed #
# #
# XREF **************************************************************** #
# _real_access() - exit through access error handler #
# #
# INPUT *************************************************************** #
# None #
# #
# OUTPUT ************************************************************** #
# None #
# #
# ALGORITHM *********************************************************** #
# Flow jumps here when an FP data fetch call gets an error #
# result. This means the operating system wants an access error frame #
# made out of the current exception stack frame. #
# So, we first call restore() which makes sure that any updated #
# -(an)+ register gets returned to its pre-exception value and then #
# we change the stack to an acess error stack frame. #
# #
#########################################################################
facc_in_b:
movq.l &0x1,%d0 # one byte
bsr.w restore # fix An
mov.w &0x0121,EXC_VOFF(%a6) # set FSLW
bra.w facc_finish
facc_in_w:
movq.l &0x2,%d0 # two bytes
bsr.w restore # fix An
mov.w &0x0141,EXC_VOFF(%a6) # set FSLW
bra.b facc_finish
facc_in_l:
movq.l &0x4,%d0 # four bytes
bsr.w restore # fix An
mov.w &0x0101,EXC_VOFF(%a6) # set FSLW
bra.b facc_finish
# here's where we actually create the access error frame from the
# current exception stack frame.
facc_finish:
mov.l USER_FPIAR(%a6),EXC_PC(%a6) # store current PC
# if the effective addressing mode was predecrement or postincrement,
# the emulation has already changed its value to the correct post-
# instruction value. but since we're exiting to the access error
# handler, then AN must be returned to its pre-instruction value.
# we do that here.
restore:
mov.b EXC_OPWORD+0x1(%a6),%d1
andi.b &0x38,%d1 # extract opmode
cmpi.b %d1,&0x18 # postinc?
beq.w rest_inc
cmpi.b %d1,&0x20 # predec?
beq.w rest_dec
rts
rest_inc:
mov.b EXC_OPWORD+0x1(%a6),%d1
andi.w &0x0007,%d1 # fetch An
tbl_rest_inc:
short ri_a0 - tbl_rest_inc
short ri_a1 - tbl_rest_inc
short ri_a2 - tbl_rest_inc
short ri_a3 - tbl_rest_inc
short ri_a4 - tbl_rest_inc
short ri_a5 - tbl_rest_inc
short ri_a6 - tbl_rest_inc
short ri_a7 - tbl_rest_inc
ri_a0:
sub.l %d0,EXC_DREGS+0x8(%a6) # fix stacked a0
rts
ri_a1:
sub.l %d0,EXC_DREGS+0xc(%a6) # fix stacked a1
rts
ri_a2:
sub.l %d0,%a2 # fix a2
rts
ri_a3:
sub.l %d0,%a3 # fix a3
rts
ri_a4:
sub.l %d0,%a4 # fix a4
rts
ri_a5:
sub.l %d0,%a5 # fix a5
rts
ri_a6:
sub.l %d0,(%a6) # fix stacked a6
rts
# if it's a fmove out instruction, we don't have to fix a7
# because we hadn't changed it yet. if it's an opclass two
# instruction (data moved in) and the exception was in supervisor
# mode, then also also wasn't updated. if it was user mode, then
# restore the correct a7 which is in the USP currently.
ri_a7:
cmpi.b EXC_VOFF(%a6),&0x30 # move in or out?
bne.b ri_a7_done # out
