* MOTOROLA MICROPROCESSOR & MEMORY TECHNOLOGY GROUP
* M68000 Hi-Performance Microprocessor Division
* M68040 Software Package
*
* M68040 Software Package Copyright (c) 1993, 1994 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.
*
* x_store.sa 3.2 1/24/91
*
* store --- store operand to memory or register
*
* Used by underflow and overflow handlers.
*
* a6 = points to fp value to be stored.
*
X_STORE IDNT 2,1 Motorola 040 Floating Point Software Package
opc011:
bsr.l g_dfmtou ;returns dest format in d0
* ;ext=00, sgl=01, dbl=10
move.l a0,a1 ;save source addr in a1
move.l EXC_EA(a6),a0 ;get the address
tst.l d0 ;if dest format is extended
beq.w dest_ext ;then branch
cmpi.l #1,d0 ;if dest format is single
beq.b short_dest_sgl ;then branch
*
* fall through to dest_dbl
*
*
* dest_dbl --- write double precision value to user space
*
*Input
* a0 -> destination address
* a1 -> source in extended precision
*Output
* a0 -> destroyed
* a1 -> destroyed
* d0 -> 0
*
*Changes extended precision to double precision.
* Note: no attempt is made to round the extended value to double.
* dbl_sign = ext_sign
* dbl_exp = ext_exp - $3fff(ext bias) + $7ff(dbl bias)
* get rid of ext integer bit
* dbl_mant = ext_mant{62:12}
*
* --------------- --------------- ---------------
* extended -> |s| exp | |1| ms mant | | ls mant |
* --------------- --------------- ---------------
* 95 64 63 62 32 31 11 0
* | |
* | |
* | |
* v v
* --------------- ---------------
* double -> |s|exp| mant | | mant |
* --------------- ---------------
* 63 51 32 31 0
*
dest_dbl:
clr.l d0 ;clear d0
move.w LOCAL_EX(a1),d0 ;get exponent
sub.w #$3fff,d0 ;subtract extended precision bias
cmp.w #$4000,d0 ;check if inf
beq.b inf ;if so, special case
add.w #$3ff,d0 ;add double precision bias
swap d0 ;d0 now in upper word
lsl.l #4,d0 ;d0 now in proper place for dbl prec exp
tst.b LOCAL_SGN(a1)
beq.b get_mant ;if positive, go process mantissa
bset.l #31,d0 ;if negative, put in sign information
* ; before continuing
bra.b get_mant ;go process mantissa
inf:
move.l #$7ff00000,d0 ;load dbl inf exponent
clr.l LOCAL_HI(a1) ;clear msb
tst.b LOCAL_SGN(a1)
beq.b dbl_inf ;if positive, go ahead and write it
bset.l #31,d0 ;if negative put in sign information
dbl_inf:
move.l d0,LOCAL_EX(a1) ;put the new exp back on the stack
bra.b dbl_wrt
get_mant:
move.l LOCAL_HI(a1),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
move.l d0,LOCAL_EX(a1) ;put the new exp back on the stack
move.l LOCAL_HI(a1),d1 ;get ms mantissa
move.l #21,d0 ;load shift count
lsl.l d0,d1 ;put lower 11 bits in upper bits
move.l d1,LOCAL_HI(a1) ;build lower lword in memory
move.l LOCAL_LO(a1),d1 ;get ls mantissa
bfextu d1{0:21},d0 ;get ls 21 bits of double
or.l d0,LOCAL_HI(a1) ;put them in double result
dbl_wrt:
move.l #$8,d0 ;byte count for double precision number
exg a0,a1 ;a0=supervisor source, a1=user dest
bsr.l mem_write ;move the number to the user's memory
rts
*
* dest_sgl --- write single precision value to user space
*
*Input
* a0 -> destination address
* a1 -> source in extended precision
*
*Output
* a0 -> destroyed
* a1 -> destroyed
* d0 -> 0
*
*Changes extended precision to single precision.
* sgl_sign = ext_sign
* sgl_exp = ext_exp - $3fff(ext bias) + $7f(sgl bias)
* get rid of ext integer bit
* sgl_mant = ext_mant{62:12}
*
* --------------- --------------- ---------------
* extended -> |s| exp | |1| ms mant | | ls mant |
* --------------- --------------- ---------------
* 95 64 63 62 40 32 31 12 0
* | |
* | |
* | |
* v v
* ---------------
* single -> |s|exp| mant |
* ---------------
* 31 22 0
*
dest_sgl:
short_dest_sgl:
clr.l d0
move.w LOCAL_EX(a1),d0 ;get exponent
sub.w #$3fff,d0 ;subtract extended precision bias
cmp.w #$4000,d0 ;check if inf
beq.b sinf ;if so, special case
add.w #$7f,d0 ;add single precision bias
swap d0 ;put exp in upper word of d0
lsl.l #7,d0 ;shift it into single exp bits
tst.b LOCAL_SGN(a1)
beq.b get_sman ;if positive, continue
bset.l #31,d0 ;if negative, put in sign first
bra.b get_sman ;get mantissa
sinf:
move.l #$7f800000,d0 ;load single inf exp to d0
tst.b LOCAL_SGN(a1)
beq.b sgl_wrt ;if positive, continue
bset.l #31,d0 ;if negative, put in sign info
bra.b sgl_wrt
get_sman:
move.l LOCAL_HI(a1),d1 ;get ms mantissa
bfextu d1{1:23},d1 ;get upper 23 bits of ms
or.l d1,d0 ;put these bits in ms word of single
sgl_wrt:
move.l d0,L_SCR1(a6) ;put the new exp back on the stack
move.l #$4,d0 ;byte count for single precision number
tst.l a0 ;users destination address
beq.b sgl_Dn ;destination is a data register
exg a0,a1 ;a0=supervisor source, a1=user dest
lea.l L_SCR1(a6),a0 ;point a0 to data
bsr.l mem_write ;move the number to the user's memory
rts
sgl_Dn:
bsr.l get_fline ;returns fline word in d0
and.w #$7,d0 ;isolate register number
move.l d0,d1 ;d1 has size:reg formatted for reg_dest
or.l #$10,d1 ;reg_dest wants size added to reg#
bra.l reg_dest ;size is X, rts in reg_dest will
* ;return to caller of dest_sgl
dest_ext:
tst.b LOCAL_SGN(a1) ;put back sign into exponent word
beq.b dstx_cont
bset.b #sign_bit,LOCAL_EX(a1)
dstx_cont:
clr.b LOCAL_SGN(a1) ;clear out the sign byte
move.l #$0c,d0 ;byte count for extended number
exg a0,a1 ;a0=supervisor source, a1=user dest
bsr.l mem_write ;move the number to the user's memory
rts
