/* -*- c -*- */
/* Copyright (C) 2013-2024 Free Software Foundation, Inc.
  Contributed by Red Hat.
  Written by DJ Delorie.

  This file is part of the GNU opcodes library.

  This library is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation; either version 3, or (at your option)
  any later version.

  It is distributed in the hope that it will be useful, but WITHOUT
  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
  License for more details.

  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
  MA 02110-1301, USA.  */

#include "sysdep.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "bfd.h"
#include "opintl.h"
#include "opcode/msp430-decode.h"

static int trace = 0;

typedef struct
{
 MSP430_Opcode_Decoded *msp430;
 int (*getbyte)(void *);
 void *ptr;
 unsigned char *op;
 int op_ptr;
 int pc;
} LocalData;

#define AU ATTRIBUTE_UNUSED
#define GETBYTE() getbyte_swapped (ld)
#define B ((unsigned long) GETBYTE ())

static int
getbyte_swapped (LocalData *ld)
{
 int b;

 if (ld->op_ptr == ld->msp430->n_bytes)
   {
     do
       {
         b = ld->getbyte (ld->ptr);
         ld->op [(ld->msp430->n_bytes++)^1] = b;
       }
     while (ld->msp430->n_bytes & 1);
   }
 return ld->op[ld->op_ptr++];
}

#define ID(x)           msp430->id = x

#define OP(n, t, r, a) (msp430->op[n].type = t,      \
                       msp430->op[n].reg = r,       \
                       msp430->op[n].addend = a)

#define OPX(n, t, r1, r2, a)     \
 (msp430->op[n].type = t,       \
  msp430->op[n].reg = r1,       \
  msp430->op[n].reg2 = r2,      \
  msp430->op[n].addend = a)

#define SYNTAX(x)       msp430->syntax = x
#define UNSUPPORTED()   msp430->syntax = "*unknown*"

#define DC(c)           OP (0, MSP430_Operand_Immediate, 0, c)
#define DR(r)           OP (0, MSP430_Operand_Register, r, 0)
#define DM(r, a)        OP (0, MSP430_Operand_Indirect, r, a)
#define DA(a)           OP (0, MSP430_Operand_Indirect, MSR_None, a)
#define AD(r, ad)       encode_ad (r, ad, ld, 0)
#define ADX(r, ad, x)   encode_ad (r, ad, ld, x)

#define SC(c)           OP (1, MSP430_Operand_Immediate, 0, c)
#define SR(r)           OP (1, MSP430_Operand_Register, r, 0)
#define SM(r, a)        OP (1, MSP430_Operand_Indirect, r, a)
#define SA(a)           OP (1, MSP430_Operand_Indirect, MSR_None, a)
#define SI(r)           OP (1, MSP430_Operand_Indirect_Postinc, r, 0)
#define AS(r, as)       encode_as (r, as, ld, 0)
#define ASX(r, as, x)   encode_as (r, as, ld, x)

#define BW(x)           msp430->size = (x ? 8 : 16)
/* The last 20 is for SWPBX.Z and SXTX.A.  */
#define ABW(a,x)        msp430->size = (a ? ((x ? 8 : 16)) : (x ? 20 : 20))

#define IMMU(bytes)     immediate (bytes, 0, ld)
#define IMMS(bytes)     immediate (bytes, 1, ld)

/* Helper macros for known status bits settings.  */
#define F_____          msp430->flags_1 = msp430->flags_0 = 0; msp430->flags_set = 0
#define F_VNZC          msp430->flags_1 = msp430->flags_0 = 0; msp430->flags_set = 0x87
#define F_0NZC          msp430->flags_1 = 0; msp430->flags_0 = 0x80; msp430->flags_set = 0x07


/* The chip is little-endian, but GETBYTE byte-swaps words because the
  decoder is based on 16-bit "words" so *this* logic is big-endian.  */

static int
immediate (int bytes, int sign_extend, LocalData *ld)
{
 unsigned long i = 0;

 switch (bytes)
   {
   case 1:
     i |= B;
     if (sign_extend && (i & 0x80))
       i -= 0x100;
     break;
   case 2:
     i |= B << 8;
     i |= B;
     if (sign_extend && (i & 0x8000))
       i -= 0x10000;
     break;
   case 3:
     i |= B << 16;
     i |= B << 8;
     i |= B;
     if (sign_extend && (i & 0x800000))
       i -= 0x1000000;
     break;
   case 4:
     i |= B << 24;
     i |= B << 16;
     i |= B << 8;
     i |= B;
     if (sign_extend && (i & 0x80000000ULL))
       i -= 0x100000000ULL;
     break;
   default:
     opcodes_error_handler
       (_("internal error: immediate() called with invalid byte count %d"),
          bytes);
     abort ();
   }
 return i;
}

/*
               PC      SP      SR      CG
 As
 00    Rn      -       -       R2      #0
 01    X(Rn)   Sym     -       X(abs)  #1
 10    (Rn)    -       -       #4      #2
 11    (Rn++)  #imm    -       #8      #-1

 Ad
 0     Rn      -       -       -       -
 1     X(Rn)   Sym     -       X(abs)  -   */

static void
encode_ad (int reg, int ad, LocalData *ld, int ext)
{
 MSP430_Opcode_Decoded *msp430 = ld->msp430;

 if (ad)
   {
     int x = IMMU(2) | (ext << 16);
     switch (reg)
       {
       case 0: /* (PC) -> Symbolic.  */
         DA (x + ld->pc + ld->op_ptr - 2);
         break;
       case 2: /* (SR) -> Absolute.  */
         DA (x);
         break;
       default:
         DM (reg, x);
         break;
       }
   }
 else
   {
     DR (reg);
   }
}

static void
encode_as (int reg, int as, LocalData *ld, int ext)
{
 MSP430_Opcode_Decoded *msp430 = ld->msp430;
 int x;

 switch (as)
   {
   case 0:
     switch (reg)
       {
       case 3:
         SC (0);
         break;
       default:
         SR (reg);
         break;
       }
     break;
   case 1:
     switch (reg)
       {
       case 0: /* PC -> Symbolic.  */
         x = IMMU(2) | (ext << 16);
         SA (x + ld->pc + ld->op_ptr - 2);
         break;
       case 2: /* SR -> Absolute.  */
         x = IMMU(2) | (ext << 16);
         SA (x);
         break;
       case 3:
         SC (1);
         break;
       default:
         x = IMMU(2) | (ext << 16);
         SM (reg, x);
         break;
       }
     break;
   case 2:
     switch (reg)
       {
       case 2:
         SC (4);
         break;
       case 3:
         SC (2);
         break;
       case MSR_None:
         SA (0);
         break;
       default:
         SM (reg, 0);
         break;
       }
     break;
   case 3:
     switch (reg)
       {
       case 0:
         {
           /* This fetch *is* the *PC++ that the opcode encodes :-)  */
           x = IMMU(2) | (ext << 16);
           SC (x);
         }
         break;
       case 2:
         SC (8);
         break;
       case 3:
         SC (-1);
         break;
       default:
         SI (reg);
         break;
       }
     break;
   }
}

static void
encode_rep_zc (int srxt, int dsxt, LocalData *ld)
{
 MSP430_Opcode_Decoded *msp430 = ld->msp430;

 msp430->repeat_reg = srxt & 1;
 msp430->repeats = dsxt;
 msp430->zc = (srxt & 2) ? 1 : 0;
}

#define REPZC(s,d) encode_rep_zc (s, d, ld)

static int
dopc_to_id (int dopc)
{
 switch (dopc)
   {
   case 4: return MSO_mov;
   case 5: return MSO_add;
   case 6: return MSO_addc;
   case 7: return MSO_subc;
   case 8: return MSO_sub;
   case 9: return MSO_cmp;
   case 10: return MSO_dadd;
   case 11: return MSO_bit;
   case 12: return MSO_bic;
   case 13: return MSO_bis;
   case 14: return MSO_xor;
   case 15: return MSO_and;
   default: return MSO_unknown;
   }
}

static int
sopc_to_id (int sop, int c)
{
 switch (sop * 2 + c)
   {
   case 0: return MSO_rrc;
   case 1: return MSO_swpb;
   case 2: return MSO_rra;
   case 3: return MSO_sxt;
   case 4: return MSO_push;
   case 5: return MSO_call;
   case 6: return MSO_reti;
   default: return MSO_unknown;
   }
}

int
msp430_decode_opcode (unsigned long pc,
                     MSP430_Opcode_Decoded *msp430,
                     int (*getbyte)(void *),
                     void *ptr)
{
 LocalData lds, *ld = &lds;
 unsigned char op_buf[20] = {0};
 unsigned char *op = op_buf;
 int raddr;
 int al_bit;
 int srxt_bits, dsxt_bits;

 lds.msp430 = msp430;
 lds.getbyte = getbyte;
 lds.ptr = ptr;
 lds.op = op;
 lds.op_ptr = 0;
 lds.pc = pc;

 memset (msp430, 0, sizeof (*msp430));

 /* These are overridden by an extension word.  */
 al_bit = 1;
 srxt_bits = 0;
 dsxt_bits = 0;

post_extension_word:
 ;

 /* 430X extention word.  */
/** 0001 1srx t l 00 dsxt       430x */

 al_bit = l;
 srxt_bits = srx * 2 + t;
 dsxt_bits = dsxt;
 op = op_buf + lds.op_ptr;
 msp430->ofs_430x = 1;
 goto post_extension_word;

/* double-op insns:
  opcode:4 sreg:4 Ad:1 BW:1 As:2 Dreg:4

  single-op insn:
  opcode:9 BW:1 Ad:2 DSreg:4

  jumps:
  opcode:3 Cond:3  pcrel:10. */

/* Double-Operand "opcode" fields.  */
/** VARY dopc 0100 0101 0110 0111 1000 1001 1010 1011 1100 1101 1110 1111 */

/** dopc sreg a b as dreg       %D%b    %1,%0                           */

 ID (dopc_to_id (dopc)); ASX (sreg, as, srxt_bits); ADX (dreg, a, dsxt_bits); ABW (al_bit, b);
 if (a == 0 && as == 0)
   REPZC (srxt_bits, dsxt_bits);

 switch (msp430->id)
   {
   case MSO_mov:       F_____; break;
   case MSO_add:       F_VNZC; break;
   case MSO_addc:      F_VNZC; break;
   case MSO_subc:      F_VNZC; break;
   case MSO_sub:       F_VNZC; break;
   case MSO_cmp:       F_VNZC; break;
   case MSO_dadd:      F_VNZC; break;
   case MSO_bit:       F_0NZC; break;
   case MSO_bic:       F_____; break;
   case MSO_bis:       F_____; break;
   case MSO_xor:       F_VNZC; break;
   case MSO_and:       F_0NZC; break;
   default: break;
   }

/** 0001 00so c b ad dreg       %S%b    %1                              */

 ID (sopc_to_id (so,c)); ASX (dreg, ad, srxt_bits); ABW (al_bit, b);

 if (ad == 0)
   REPZC (srxt_bits, dsxt_bits);

 /* The helper functions encode for source, but it's
    both source and dest, with a few documented exceptions.  */
 msp430->op[0] = msp430->op[1];

 /* RETI ignores the operand.  */
 if (msp430->id == MSO_reti)
   msp430->syntax = "%S";

 switch (msp430->id)
   {
   case MSO_rrc:       F_VNZC; break;
   case MSO_swpb:      F_____; break;
   case MSO_rra:       F_0NZC; break;
   case MSO_sxt:       F_0NZC; break;
   case MSO_push:      F_____; break;
   case MSO_call:      F_____; break;
   case MSO_reti:      F_VNZC; break;
   default: break;
   }

 /* 20xx 0010 0000 ---- ----
    3cxx 0011 1100 ---- ----
         001j mp-- ---- ----.  */
/** 001jmp aa addrlsbs          %J      %1                              */

 raddr = (aa << 9) | (addrlsbs << 1);
 if (raddr & 0x400)
   raddr = raddr - 0x800;
 /* This is a pc-relative jump, but we don't use SM because that
    would load the target address from the memory at X(PC), not use
    PC+X *as* the address.  So we use SC to use the address, not the
    data at that address.  */
 ID (MSO_jmp); SC (pc + raddr + msp430->n_bytes);
 msp430->cond = jmp;

 /* Extended instructions.  */

/** 0000 srcr 0000 dstr         MOVA @%1, %0 */
 ID (MSO_mov); SM (srcr, 0); DR (dstr);
 msp430->size = 20;
 msp430->ofs_430x = 1;

/** 0000 srcr 0001 dstr         MOVA @%1+, %0 */
 ID (MSO_mov); SI (srcr); DR (dstr);
 msp430->size = 20;
 msp430->ofs_430x = 1;

/** 0000 srcr 0010 dstr         MOVA &%1, %0 */
 ID (MSO_mov); SA ((srcr << 16) + IMMU(2)); DR (dstr);
 msp430->size = 20;
 msp430->ofs_430x = 1;

/** 0000 srcr 0011 dstr         MOVA %1, %0 */
 ID (MSO_mov); SM (srcr, IMMS(2)); DR (dstr);
 msp430->size = 20;
 msp430->ofs_430x = 1;

/** 0000 srcr 0110 dstr         MOVA %1, &%0 */
 ID (MSO_mov); SR (srcr); DA ((dstr << 16) + IMMU(2));
 msp430->size = 20;
 msp430->ofs_430x = 1;

/** 0000 srcr 0111 dstr         MOVA %1, &%0 */
 ID (MSO_mov); SR (srcr); DM (dstr, IMMS(2));
 msp430->size = 20;
 msp430->ofs_430x = 1;

/** 0000 srcr 1000 dstr         MOVA %1, %0 */
 ID (MSO_mov); SC ((srcr << 16) + IMMU(2)); DR (dstr);
 msp430->size = 20;
 msp430->ofs_430x = 1;

/** 0000 srcr 1001 dstr         CMPA %1, %0 */
 ID (MSO_cmp); SC ((srcr << 16) + IMMU(2)); DR (dstr);
 msp430->size = 20;
 msp430->ofs_430x = 1;
 F_VNZC;

/** 0000 srcr 1010 dstr         ADDA %1, %0 */
 ID (MSO_add); SC ((srcr << 16) + IMMU(2)); DR (dstr);
 msp430->size = 20;
 msp430->ofs_430x = 1;
 F_VNZC;

/** 0000 srcr 1011 dstr         SUBA %1, %0 */
 ID (MSO_sub); SC ((srcr << 16) + IMMU(2)); DR (dstr);
 msp430->size = 20;
 msp430->ofs_430x = 1;
 F_VNZC;

/** 0000 srcr 1011 dstr         SUBA %1, %0 */
 ID (MSO_sub); SC ((srcr << 16) + IMMU(2)); DR (dstr);
 msp430->size = 20;
 msp430->ofs_430x = 1;
 F_VNZC;

/** 0000 srcr 1100 dstr         MOVA %1, %0 */
 ID (MSO_mov); SR (srcr); DR (dstr);
 msp430->size = 20;
 msp430->ofs_430x = 1;

/** 0000 srcr 1101 dstr         CMPA %1, %0 */
 ID (MSO_cmp); SR (srcr); DR (dstr);
 msp430->size = 20;
 msp430->ofs_430x = 1;
 F_VNZC;

/** 0000 srcr 1110 dstr         ADDA %1, %0 */
 ID (MSO_add); SR (srcr); DR (dstr);
 msp430->size = 20;
 msp430->ofs_430x = 1;
 F_VNZC;

/** 0000 srcr 1111 dstr         SUBA %1, %0 */
 ID (MSO_sub); SR (srcr); DR (dstr);
 msp430->size = 20;
 msp430->ofs_430x = 1;
 F_VNZC;

/** 0000 bt00 010w dstr         RRCM.A %c, %0 */
 ID (MSO_rrc); DR (dstr); SR (dstr);
 msp430->repeats = bt;
 msp430->size = w ? 16 : 20;
 msp430->ofs_430x = 1;
 F_0NZC;

/** 0000 bt01 010w dstr         RRAM.A %c, %0 */
 ID (MSO_rra); DR (dstr); SR (dstr);
 msp430->repeats = bt;
 msp430->size = w ? 16 : 20;
 msp430->ofs_430x = 1;
 F_0NZC;

/** 0000 bt10 010w dstr         RLAM.A %c, %0 */
 ID (MSO_add); DR (dstr); SR (dstr);
 msp430->repeats = bt;
 msp430->size = w ? 16 : 20;
 msp430->ofs_430x = 1;
 F_0NZC;

/** 0000 bt11 010w dstr         RRUM.A %c, %0 */
 ID (MSO_rru); DR (dstr); SR (dstr);
 msp430->repeats = bt;
 msp430->size = w ? 16 : 20;
 msp430->ofs_430x = 1;
 F_0NZC;

/** 0001 0011 0000 0000         RETI */
 ID (MSO_reti);
 msp430->size = 20;
 msp430->ofs_430x = 1;

/** 0001 0011 01as dstr         CALLA %0 */
 ID (MSO_call); AS (dstr, as);
 msp430->size = 20;
 msp430->ofs_430x = 1;

/** 0001 0011 1000 extb         CALLA %0 */
 ID (MSO_call); SA (IMMU(2) | (extb << 16));
 msp430->size = 20;
 msp430->ofs_430x = 1;

/** 0001 0011 1001 extb         CALLA %0 */
 raddr = IMMU(2) | (extb << 16);
 if (raddr & 0x80000)
   raddr -= 0x100000;
 ID (MSO_call); SA (pc + raddr + msp430->n_bytes);
 msp430->size = 20;
 msp430->ofs_430x = 1;

/** 0001 0011 1011 extb         CALLA %0 */
 ID (MSO_call); SC (IMMU(2) | (extb << 16));
 msp430->size = 20;
 msp430->ofs_430x = 1;

/** 0001 010w bits srcr         PUSHM.A %0 */
 ID (MSO_push); SR (srcr);
 msp430->size = w ? 16 : 20;
 msp430->repeats = bits;
 msp430->ofs_430x = 1;

/** 0001 011w bits dstr         POPM.A %0 */
 ID (MSO_pop); DR (dstr);
 msp430->size = w ? 16 : 20;
 msp430->repeats = bits;
 msp430->ofs_430x = 1;

/** */

 return msp430->n_bytes;
}

You are viewing proxied material from ftp.icm.edu.pl. The copyright of proxied material belongs to its original authors. Any comments or complaints in relation to proxied material should be directed to the original authors of the content concerned. Please see the disclaimer for more details.