Shamusworld >> Repos - virtualjaguar/blob - src/m68000/m68kdasm.c

   1 //
   2 // m68kdasm.c: 68000 instruction disassembly
   3 //
   4 // Originally part of the UAE 68000 cpu core
   5 // by Bernd Schmidt
   6 //
   7 // Adapted to Virtual Jaguar by James Hammons
   8 //
   9 // This file is distributed under the GNU Public License, version 3 or at your
  10 // option any later version. Read the file GPLv3 for details.
  11 //
  12
  13 #include <string.h>
  14 #include "cpudefs.h"
  15 #include "cpuextra.h"
  16 #include "inlines.h"
  17 #include "readcpu.h"
  18
  19
  20 // Stuff from m68kinterface.c
  21 extern unsigned long IllegalOpcode(uint32_t opcode);
  22 extern cpuop_func * cpuFunctionTable[65536];
  23
  24 // Local "global" variables
  25 static long int m68kpc_offset;
  26
  27 #if 0
  28 #define get_ibyte_1(o) get_byte(regs.pc + (regs.pc_p - regs.pc_oldp) + (o) + 1)
  29 #define get_iword_1(o) get_word(regs.pc + (regs.pc_p - regs.pc_oldp) + (o))
  30 #define get_ilong_1(o) get_long(regs.pc + (regs.pc_p - regs.pc_oldp) + (o))
  31 #else
  32 #define get_ibyte_1(o) m68k_read_memory_8(regs.pc + (o) + 1)
  33 #define get_iword_1(o) m68k_read_memory_16(regs.pc + (o))
  34 #define get_ilong_1(o) m68k_read_memory_32(regs.pc + (o))
  35 #endif
  36
  37
  38 int32_t ShowEA(FILE * f, int reg, amodes mode, wordsizes size, char * buf)
  39 {
  40         uint16_t dp;
  41         int8_t disp8;
  42         int16_t disp16;
  43         int r;
  44         uint32_t dispreg;
  45         uint32_t addr;
  46         int32_t offset = 0;
  47         char buffer[80];
  48
  49         switch (mode)
  50         {
  51         case Dreg:
  52                 sprintf(buffer,"D%d", reg);
  53                 break;
  54         case Areg:
  55                 sprintf(buffer,"A%d", reg);
  56                 break;
  57         case Aind:
  58                 sprintf(buffer,"(A%d)", reg);
  59                 break;
  60         case Aipi:
  61                 sprintf(buffer,"(A%d)+", reg);
  62                 break;
  63         case Apdi:
  64                 sprintf(buffer,"-(A%d)", reg);
  65                 break;
  66         case Ad16:
  67                 disp16 = get_iword_1(m68kpc_offset); m68kpc_offset += 2;
  68                 addr = m68k_areg(regs,reg) + (int16_t)disp16;
  69                 sprintf(buffer,"(A%d,$%04X) == $%08lX", reg, disp16 & 0xFFFF,
  70                         (unsigned long)addr);
  71                 break;
  72         case Ad8r:
  73                 dp = get_iword_1(m68kpc_offset); m68kpc_offset += 2;
  74                 disp8 = dp & 0xFF;
  75                 r = (dp & 0x7000) >> 12;
  76                 dispreg = (dp & 0x8000 ? m68k_areg(regs,r) : m68k_dreg(regs,r));
  77
  78                 if (!(dp & 0x800))
  79                         dispreg = (int32_t)(int16_t)(dispreg);
  80
  81                 dispreg <<= (dp >> 9) & 3;
  82
  83                 if (dp & 0x100)
  84                 {
  85                         int32_t outer = 0, disp = 0;
  86                         int32_t base = m68k_areg(regs,reg);
  87                         char name[10];
  88                         sprintf (name,"A%d, ",reg);
  89                         if (dp & 0x80) { base = 0; name[0] = 0; }
  90                         if (dp & 0x40) dispreg = 0;
  91                         if ((dp & 0x30) == 0x20) { disp = (int32_t)(int16_t)get_iword_1(m68kpc_offset); m68kpc_offset += 2; }
  92                         if ((dp & 0x30) == 0x30) { disp = get_ilong_1(m68kpc_offset); m68kpc_offset += 4; }
  93                         base += disp;
  94
  95                         if ((dp & 0x3) == 0x2) { outer = (int32_t)(int16_t)get_iword_1(m68kpc_offset); m68kpc_offset += 2; }
  96                         if ((dp & 0x3) == 0x3) { outer = get_ilong_1(m68kpc_offset); m68kpc_offset += 4; }
  97
  98                         if (!(dp & 4)) base += dispreg;
  99                         if (dp & 3) base = m68k_read_memory_32(base);
 100                         if (dp & 4) base += dispreg;
 101
 102                         addr = base + outer;
 103                         sprintf(buffer,"(%s%c%d.%c*%d+%ld)+%ld == $%08lX", name,
 104                                 dp & 0x8000 ? 'A' : 'D', (int)r, dp & 0x800 ? 'L' : 'W',
 105                                 1 << ((dp >> 9) & 3),
 106                                 (long)disp, (long)outer, (unsigned long)addr);
 107                 }
 108                 else
 109                 {
 110                         addr = m68k_areg(regs,reg) + (int32_t)((int8_t)disp8) + dispreg;
 111                         sprintf (buffer,"(A%d, %c%d.%c*%d, $%02X) == $%08lX", reg,
 112                                 dp & 0x8000 ? 'A' : 'D', (int)r, dp & 0x800 ? 'L' : 'W',
 113                                 1 << ((dp >> 9) & 3), disp8, (unsigned long)addr);
 114                 }
 115                 break;
 116         case PC16:
 117                 addr = m68k_getpc() + m68kpc_offset;
 118                 disp16 = get_iword_1(m68kpc_offset); m68kpc_offset += 2;
 119                 addr += (int16_t)disp16;
 120                 sprintf(buffer,"(PC,$%04X) == $%08lX", disp16 & 0xffff,(unsigned long)addr);
 121                 break;
 122         case PC8r:
 123                 addr = m68k_getpc() + m68kpc_offset;
 124                 dp = get_iword_1(m68kpc_offset); m68kpc_offset += 2;
 125                 disp8 = dp & 0xFF;
 126                 r = (dp & 0x7000) >> 12;
 127                 dispreg = dp & 0x8000 ? m68k_areg(regs,r) : m68k_dreg(regs,r);
 128
 129                 if (!(dp & 0x800))
 130                         dispreg = (int32_t)(int16_t)(dispreg);
 131
 132                 dispreg <<= (dp >> 9) & 3;
 133
 134                 if (dp & 0x100)
 135                 {
 136                         int32_t outer = 0,disp = 0;
 137                         int32_t base = addr;
 138                         char name[10];
 139                         sprintf (name,"PC, ");
 140                         if (dp & 0x80) { base = 0; name[0] = 0; }
 141                         if (dp & 0x40) dispreg = 0;
 142                         if ((dp & 0x30) == 0x20) { disp = (int32_t)(int16_t)get_iword_1(m68kpc_offset); m68kpc_offset += 2; }
 143                         if ((dp & 0x30) == 0x30) { disp = get_ilong_1(m68kpc_offset); m68kpc_offset += 4; }
 144                         base += disp;
 145
 146                         if ((dp & 0x3) == 0x2)
 147                         {
 148                                 outer = (int32_t)(int16_t)get_iword_1(m68kpc_offset);
 149                                 m68kpc_offset += 2;
 150                         }
 151
 152                         if ((dp & 0x3) == 0x3)
 153                         {
 154                                 outer = get_ilong_1(m68kpc_offset);
 155                                 m68kpc_offset += 4;
 156                         }
 157
 158                         if (!(dp & 4)) base += dispreg;
 159                         if (dp & 3) base = m68k_read_memory_32(base);
 160                         if (dp & 4) base += dispreg;
 161
 162                         addr = base + outer;
 163                         sprintf(buffer,"(%s%c%d.%c*%d+%ld)+%ld == $%08lX", name,
 164                                 dp & 0x8000 ? 'A' : 'D', (int)r, dp & 0x800 ? 'L' : 'W',
 165                                 1 << ((dp >> 9) & 3), (long)disp, (long)outer, (unsigned long)addr);
 166                 }
 167                 else
 168                 {
 169                         addr += (int32_t)((int8_t)disp8) + dispreg;
 170                         sprintf(buffer,"(PC, %c%d.%c*%d, $%02X) == $%08lX", dp & 0x8000 ? 'A' : 'D',
 171                                 (int)r, dp & 0x800 ? 'L' : 'W',  1 << ((dp >> 9) & 3),
 172                                 disp8, (unsigned long)addr);
 173                 }
 174                 break;
 175         case absw:
 176                 sprintf(buffer,"$%08lX", (unsigned long)(int32_t)(int16_t)get_iword_1(m68kpc_offset));
 177                 m68kpc_offset += 2;
 178                 break;
 179         case absl:
 180                 sprintf(buffer,"$%08lX", (unsigned long)get_ilong_1(m68kpc_offset));
 181                 m68kpc_offset += 4;
 182                 break;
 183         case imm:
 184                 switch (size)
 185                 {
 186                 case sz_byte:
 187                         sprintf(buffer,"#$%02X", (unsigned int)(get_iword_1(m68kpc_offset) & 0xFF));
 188                         m68kpc_offset += 2;
 189                         break;
 190                 case sz_word:
 191                         sprintf(buffer,"#$%04X", (unsigned int)(get_iword_1(m68kpc_offset) & 0xFFFF));
 192                         m68kpc_offset += 2;
 193                         break;
 194                 case sz_long:
 195                         sprintf(buffer,"#$%08lX", (unsigned long)(get_ilong_1(m68kpc_offset)));
 196                         m68kpc_offset += 4;
 197                         break;
 198                 default:
 199                         break;
 200                 }
 201                 break;
 202         case imm0:
 203                 offset = (int32_t)(int8_t)get_iword_1(m68kpc_offset);
 204                 m68kpc_offset += 2;
 205                 sprintf (buffer,"#$%02X", (unsigned int)(offset & 0xFF));
 206                 break;
 207         case imm1:
 208                 offset = (int32_t)(int16_t)get_iword_1(m68kpc_offset);
 209                 m68kpc_offset += 2;
 210                 sprintf (buffer,"#$%04X", (unsigned int)(offset & 0xFFFF));
 211                 break;
 212         case imm2:
 213                 offset = (int32_t)get_ilong_1(m68kpc_offset);
 214                 m68kpc_offset += 4;
 215                 sprintf(buffer,"#$%08lX", (unsigned long)offset);
 216                 break;
 217         case immi:
 218                 offset = (int32_t)(int8_t)(reg & 0xFF);
 219                 sprintf(buffer,"#$%08lX", (unsigned long)offset);
 220                 break;
 221         default:
 222                 break;
 223         }
 224
 225         if (buf == 0)
 226                 fprintf(f, "%s", buffer);
 227         else
 228                 strcat(buf, buffer);
 229
 230         return offset;
 231 }
 232
 233
 234 //void m68k_disasm(FILE * f, uint32_t addr, uint32_t * nextpc, int cnt)
 235 unsigned int m68k_disasm(char * output, uint32_t addr, uint32_t * nextpc, int cnt)
 236 {
 237         char f[256], str[256];
 238         static const char * const ccnames[] =
 239                 { "RA","RN","HI","LS","CC","CS","NE","EQ",
 240                   "VC","VS","PL","MI","GE","LT","GT","LE" };
 241
 242         str[0] = 0;
 243         output[0] = 0;
 244         uint32_t newpc = 0;
 245         m68kpc_offset = addr - m68k_getpc();
 246         long int pcOffsetSave = m68kpc_offset;
 247         int opwords;
 248
 249         while (cnt-- > 0)
 250         {
 251                 char instrname[20], * ccpt;
 252                 uint32_t opcode;
 253                 const struct mnemolookup * lookup;
 254                 struct instr * dp;
 255 //              sprintf(f, "%06lX: ", m68k_getpc() + m68kpc_offset);
 256 //              strcat(str, f);
 257
 258 #if 0
 259                 for(opwords=0; opwords<5; opwords++)
 260                 {
 261                         sprintf(f, "%04X ", get_iword_1(m68kpc_offset + opwords * 2));
 262                         strcat(str, f);
 263                 }
 264 #endif
 265
 266                 opcode = get_iword_1(m68kpc_offset);
 267                 m68kpc_offset += 2;
 268
 269                 if (cpuFunctionTable[opcode] == IllegalOpcode)
 270                 {
 271                         opcode = 0x4AFC;
 272                 }
 273
 274                 dp = table68k + opcode;
 275
 276                 for(lookup=lookuptab; lookup->mnemo!=dp->mnemo; lookup++)
 277                         ;
 278
 279                 strcpy(instrname, lookup->name);
 280                 ccpt = strstr(instrname, "cc");
 281
 282                 if (ccpt != 0)
 283                 {
 284                         strncpy(ccpt, ccnames[dp->cc], 2);
 285                 }
 286
 287                 sprintf(f, "%s", instrname);
 288                 strcat(str, f);
 289
 290 #if 0
 291                 switch (dp->size)
 292                 {
 293                         case sz_byte: sprintf(f, ".B "); break;
 294                         case sz_word: sprintf(f, ".W "); break;
 295                         case sz_long: sprintf(f, ".L "); break;
 296                         default: sprintf(f, "   "); break;
 297                 }
 298                 strcat(str, f);
 299 #else
 300                 switch (dp->size)
 301                 {
 302                         case sz_byte: strcat(str, ".B\t"); break;
 303                         case sz_word: strcat(str, ".W\t"); break;
 304                         case sz_long: strcat(str, ".L\t"); break;
 305                         default: strcat(str, "\t"); break;
 306                 }
 307 #endif
 308
 309                 if (dp->suse)
 310                 {
 311                         f[0] = 0;
 312                         newpc = m68k_getpc() + m68kpc_offset;
 313                         newpc += ShowEA(0, dp->sreg, dp->smode, dp->size, f);
 314                         strcat(str, f);
 315                 }
 316
 317 #if 1
 318                 if (dp->suse && dp->duse)
 319                 {
 320 //                      sprintf(f, ",");
 321 //                      strcat(str, f);
 322                         strcat(str, ", ");
 323                 }
 324 #endif
 325
 326                 if (dp->duse)
 327                 {
 328                         f[0] = 0;
 329                         newpc = m68k_getpc() + m68kpc_offset;
 330                         newpc += ShowEA(0, dp->dreg, dp->dmode, dp->size, f);
 331                         strcat(str, f);
 332                 }
 333
 334                 if (ccpt != 0)
 335                 {
 336                         if (cctrue(dp->cc))
 337                                 sprintf(f, " == %08lX (TRUE)", (long)newpc);
 338                         else
 339                                 sprintf(f, " == %08lX (FALSE)", (long)newpc);
 340
 341                         strcat(str, f);
 342                 }
 343                 else if ((opcode & 0xFF00) == 0x6100) // BSR
 344                 {
 345                         sprintf(f, " == %08lX", (long)newpc);
 346                         strcat(str, f);
 347                 }
 348
 349 //              fprintf(f, "\n");
 350         }
 351
 352 //      if (nextpc)
 353 //              *nextpc = m68k_getpc() + m68kpc_offset;
 354
 355         long int numberOfBytes = m68kpc_offset - pcOffsetSave;
 356
 357         for(opwords=0; opwords<5; opwords++)
 358         {
 359                 if (((opwords + 1) * 2) <= numberOfBytes)
 360                         sprintf(f, "%04X ", get_iword_1(pcOffsetSave + opwords * 2));
 361                 else
 362                         sprintf(f, "     ");
 363
 364                 strcat(output, f);
 365         }
 366
 367         strcat(output, str);
 368
 369         return numberOfBytes;
 370 }
 371
 372 //
 373 // Disasemble one instruction at pc and store in str_buff
 374 //
 375 unsigned int m68k_disassemble(char * str_buff, unsigned int pc, unsigned int cpu_type)
 376 {
 377         return m68k_disasm(str_buff, pc, 0, 1);
 378 }