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[/] [eco32/] [trunk/] [sim/] [disasm.c] - Blame information for rev 239

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Line No. Rev Author Line
1 8 hellwig
/*
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 * disasm.c -- disassembler
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 */
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "common.h"
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#include "console.h"
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#include "error.h"
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#include "instr.h"
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#include "disasm.h"
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static char instrBuffer[100];
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static void disasmN(char *opName, Word immed) {
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  if (immed == 0) {
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    sprintf(instrBuffer, "%-7s", opName);
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  } else {
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    sprintf(instrBuffer, "%-7s %08X", opName, immed);
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  }
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}
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static void disasmRH(char *opName, int r1, Half immed) {
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  sprintf(instrBuffer, "%-7s $%d,%04X", opName, r1, immed);
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}
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static void disasmRHH(char *opName, int r1, Half immed) {
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  sprintf(instrBuffer, "%-7s $%d,%08X", opName, r1, (Word) immed << 16);
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}
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static void disasmRRH(char *opName, int r1, int r2, Half immed) {
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  sprintf(instrBuffer, "%-7s $%d,$%d,%04X", opName, r1, r2, immed);
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}
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static void disasmRRS(char *opName, int r1, int r2, Half immed) {
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  sprintf(instrBuffer, "%-7s $%d,$%d,%s%04X", opName, r1, r2,
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          SIGN(16) & immed ? "-" : "+",
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          SIGN(16) & immed ? -SEXT16(immed) : SEXT16(immed));
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}
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static void disasmRRR(char *opName, int r1, int r2, int r3) {
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  sprintf(instrBuffer, "%-7s $%d,$%d,$%d", opName, r1, r2, r3);
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}
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static void disasmRRB(char *opName, int r1, int r2, Half offset, Word locus) {
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  sprintf(instrBuffer, "%-7s $%d,$%d,%08X", opName,
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          r1, r2, (locus + 4) + (SEXT16(offset) << 2));
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}
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static void disasmJ(char *opName, Word offset, Word locus) {
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  sprintf(instrBuffer, "%-7s %08X", opName,
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          (locus + 4) + (SEXT26(offset) << 2));
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}
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static void disasmJR(char *opName, int r1) {
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  sprintf(instrBuffer, "%-7s $%d", opName, r1);
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}
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char *disasm(Word instr, Word locus) {
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  Byte opcode;
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  Instr *ip;
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  opcode = (instr >> 26) & 0x3F;
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  ip = instrCodeTbl[opcode];
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  if (ip == NULL) {
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    disasmN("???", 0);
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  } else {
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    switch (ip->format) {
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      case FORMAT_N:
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        disasmN(ip->name, instr & 0x03FFFFFF);
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        break;
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      case FORMAT_RH:
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        disasmRH(ip->name, (instr >> 16) & 0x1F, instr & 0x0000FFFF);
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        break;
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      case FORMAT_RHH:
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        disasmRHH(ip->name, (instr >> 16) & 0x1F, instr & 0x0000FFFF);
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        break;
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      case FORMAT_RRH:
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        disasmRRH(ip->name, (instr >> 16) & 0x1F,
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                  (instr >> 21) & 0x1F, instr & 0x0000FFFF);
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        break;
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      case FORMAT_RRS:
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        disasmRRS(ip->name, (instr >> 16) & 0x1F,
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                  (instr >> 21) & 0x1F, instr & 0x0000FFFF);
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        break;
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      case FORMAT_RRR:
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        disasmRRR(ip->name, (instr >> 11) & 0x1F,
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                  (instr >> 21) & 0x1F, (instr >> 16) & 0x1F);
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        break;
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      case FORMAT_RRX:
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        if ((opcode & 1) == 0) {
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          /* the FORMAT_RRR variant */
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          disasmRRR(ip->name, (instr >> 11) & 0x1F,
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                    (instr >> 21) & 0x1F, (instr >> 16) & 0x1F);
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        } else {
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          /* the FORMAT_RRH variant */
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          disasmRRH(ip->name, (instr >> 16) & 0x1F,
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                    (instr >> 21) & 0x1F, instr & 0x0000FFFF);
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        }
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        break;
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      case FORMAT_RRY:
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        if ((opcode & 1) == 0) {
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          /* the FORMAT_RRR variant */
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          disasmRRR(ip->name, (instr >> 11) & 0x1F,
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                    (instr >> 21) & 0x1F, (instr >> 16) & 0x1F);
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        } else {
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          /* the FORMAT_RRS variant */
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          disasmRRS(ip->name, (instr >> 16) & 0x1F,
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                    (instr >> 21) & 0x1F, instr & 0x0000FFFF);
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        }
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        break;
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      case FORMAT_RRB:
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        disasmRRB(ip->name, (instr >> 21) & 0x1F,
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                  (instr >> 16) & 0x1F, instr & 0x0000FFFF, locus);
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        break;
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      case FORMAT_J:
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        disasmJ(ip->name, instr & 0x03FFFFFF, locus);
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        break;
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      case FORMAT_JR:
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        disasmJR(ip->name, (instr >> 21) & 0x1F);
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        break;
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      default:
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        error("illegal entry in instruction table");
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    }
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  }
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  return instrBuffer;
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}

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