lib/soft386/opcodes.c

   1 /*
   2  * COPYRIGHT:       GPL - See COPYING in the top level directory
   3  * PROJECT:         386/486 CPU Emulation Library
   4  * FILE:            opcodes.c
   5  * PURPOSE:         Opcode handlers.
   6  * PROGRAMMERS:     Aleksandar Andrejevic <theflash AT sdf DOT lonestar DOT org>
   7  */
   8
   9 /* INCLUDES *******************************************************************/
  10
  11 // #define WIN32_NO_STATUS
  12 // #define _INC_WINDOWS
  13 #include <windef.h>
  14
  15 #include <soft386.h>
  16 #include "opcodes.h"
  17 #include "common.h"
  18
  19 // #define NDEBUG
  20 #include <debug.h>
  21
  22 /* PUBLIC VARIABLES ***********************************************************/
  23
  24 SOFT386_OPCODE_HANDLER_PROC
  25 Soft386OpcodeHandlers[SOFT386_NUM_OPCODE_HANDLERS] =
  26 {
  27     NULL, // TODO: OPCODE 0x00 NOT SUPPORTED
  28     NULL, // TODO: OPCODE 0x01 NOT SUPPORTED
  29     NULL, // TODO: OPCODE 0x02 NOT SUPPORTED
  30     NULL, // TODO: OPCODE 0x03 NOT SUPPORTED
  31     NULL, // TODO: OPCODE 0x04 NOT SUPPORTED
  32     NULL, // TODO: OPCODE 0x05 NOT SUPPORTED
  33     NULL, // TODO: OPCODE 0x06 NOT SUPPORTED
  34     NULL, // TODO: OPCODE 0x07 NOT SUPPORTED
  35     NULL, // TODO: OPCODE 0x08 NOT SUPPORTED
  36     NULL, // TODO: OPCODE 0x09 NOT SUPPORTED
  37     NULL, // TODO: OPCODE 0x0A NOT SUPPORTED
  38     NULL, // TODO: OPCODE 0x0B NOT SUPPORTED
  39     NULL, // TODO: OPCODE 0x0C NOT SUPPORTED
  40     NULL, // TODO: OPCODE 0x0D NOT SUPPORTED
  41     NULL, // TODO: OPCODE 0x0E NOT SUPPORTED
  42     NULL, // TODO: OPCODE 0x0F NOT SUPPORTED
  43     NULL, // TODO: OPCODE 0x10 NOT SUPPORTED
  44     NULL, // TODO: OPCODE 0x11 NOT SUPPORTED
  45     NULL, // TODO: OPCODE 0x12 NOT SUPPORTED
  46     NULL, // TODO: OPCODE 0x13 NOT SUPPORTED
  47     NULL, // TODO: OPCODE 0x14 NOT SUPPORTED
  48     NULL, // TODO: OPCODE 0x15 NOT SUPPORTED
  49     NULL, // TODO: OPCODE 0x16 NOT SUPPORTED
  50     NULL, // TODO: OPCODE 0x17 NOT SUPPORTED
  51     NULL, // TODO: OPCODE 0x18 NOT SUPPORTED
  52     NULL, // TODO: OPCODE 0x19 NOT SUPPORTED
  53     NULL, // TODO: OPCODE 0x1A NOT SUPPORTED
  54     NULL, // TODO: OPCODE 0x1B NOT SUPPORTED
  55     NULL, // TODO: OPCODE 0x1C NOT SUPPORTED
  56     NULL, // TODO: OPCODE 0x1D NOT SUPPORTED
  57     NULL, // TODO: OPCODE 0x1E NOT SUPPORTED
  58     NULL, // TODO: OPCODE 0x1F NOT SUPPORTED
  59     NULL, // TODO: OPCODE 0x20 NOT SUPPORTED
  60     NULL, // TODO: OPCODE 0x21 NOT SUPPORTED
  61     NULL, // TODO: OPCODE 0x22 NOT SUPPORTED
  62     NULL, // TODO: OPCODE 0x23 NOT SUPPORTED
  63     NULL, // TODO: OPCODE 0x24 NOT SUPPORTED
  64     NULL, // TODO: OPCODE 0x25 NOT SUPPORTED
  65     Soft386OpcodePrefix,
  66     NULL, // TODO: OPCODE 0x27 NOT SUPPORTED
  67     NULL, // TODO: OPCODE 0x28 NOT SUPPORTED
  68     NULL, // TODO: OPCODE 0x29 NOT SUPPORTED
  69     NULL, // TODO: OPCODE 0x2A NOT SUPPORTED
  70     NULL, // TODO: OPCODE 0x2B NOT SUPPORTED
  71     NULL, // TODO: OPCODE 0x2C NOT SUPPORTED
  72     NULL, // TODO: OPCODE 0x2D NOT SUPPORTED
  73     Soft386OpcodePrefix,
  74     NULL, // TODO: OPCODE 0x2F NOT SUPPORTED
  75     NULL, // TODO: OPCODE 0x30 NOT SUPPORTED
  76     NULL, // TODO: OPCODE 0x31 NOT SUPPORTED
  77     NULL, // TODO: OPCODE 0x32 NOT SUPPORTED
  78     NULL, // TODO: OPCODE 0x33 NOT SUPPORTED
  79     NULL, // TODO: OPCODE 0x34 NOT SUPPORTED
  80     NULL, // TODO: OPCODE 0x35 NOT SUPPORTED
  81     Soft386OpcodePrefix,
  82     NULL, // TODO: OPCODE 0x37 NOT SUPPORTED
  83     NULL, // TODO: OPCODE 0x38 NOT SUPPORTED
  84     NULL, // TODO: OPCODE 0x39 NOT SUPPORTED
  85     NULL, // TODO: OPCODE 0x3A NOT SUPPORTED
  86     NULL, // TODO: OPCODE 0x3B NOT SUPPORTED
  87     NULL, // TODO: OPCODE 0x3C NOT SUPPORTED
  88     NULL, // TODO: OPCODE 0x3D NOT SUPPORTED
  89     Soft386OpcodePrefix,
  90     NULL, // TODO: OPCODE 0x3F NOT SUPPORTED
  91     Soft386OpcodeIncrement,
  92     Soft386OpcodeIncrement,
  93     Soft386OpcodeIncrement,
  94     Soft386OpcodeIncrement,
  95     Soft386OpcodeIncrement,
  96     Soft386OpcodeIncrement,
  97     Soft386OpcodeIncrement,
  98     Soft386OpcodeIncrement,
  99     Soft386OpcodeDecrement,
 100     Soft386OpcodeDecrement,
 101     Soft386OpcodeDecrement,
 102     Soft386OpcodeDecrement,
 103     Soft386OpcodeDecrement,
 104     Soft386OpcodeDecrement,
 105     Soft386OpcodeDecrement,
 106     Soft386OpcodeDecrement,
 107     Soft386OpcodePushReg,
 108     Soft386OpcodePushReg,
 109     Soft386OpcodePushReg,
 110     Soft386OpcodePushReg,
 111     Soft386OpcodePushReg,
 112     Soft386OpcodePushReg,
 113     Soft386OpcodePushReg,
 114     Soft386OpcodePushReg,
 115     Soft386OpcodePopReg,
 116     Soft386OpcodePopReg,
 117     Soft386OpcodePopReg,
 118     Soft386OpcodePopReg,
 119     Soft386OpcodePopReg,
 120     Soft386OpcodePopReg,
 121     Soft386OpcodePopReg,
 122     Soft386OpcodePopReg,
 123     NULL, // TODO: OPCODE 0x60 NOT SUPPORTED
 124     NULL, // TODO: OPCODE 0x61 NOT SUPPORTED
 125     NULL, // TODO: OPCODE 0x62 NOT SUPPORTED
 126     NULL, // TODO: OPCODE 0x63 NOT SUPPORTED
 127     Soft386OpcodePrefix,
 128     Soft386OpcodePrefix,
 129     Soft386OpcodePrefix,
 130     Soft386OpcodePrefix,
 131     NULL, // TODO: OPCODE 0x68 NOT SUPPORTED
 132     NULL, // TODO: OPCODE 0x69 NOT SUPPORTED
 133     NULL, // TODO: OPCODE 0x6A NOT SUPPORTED
 134     NULL, // TODO: OPCODE 0x6B NOT SUPPORTED
 135     NULL, // TODO: OPCODE 0x6C NOT SUPPORTED
 136     NULL, // TODO: OPCODE 0x6D NOT SUPPORTED
 137     NULL, // TODO: OPCODE 0x6E NOT SUPPORTED
 138     NULL, // TODO: OPCODE 0x6F NOT SUPPORTED
 139     Soft386OpcodeShortConditionalJmp,
 140     Soft386OpcodeShortConditionalJmp,
 141     Soft386OpcodeShortConditionalJmp,
 142     Soft386OpcodeShortConditionalJmp,
 143     Soft386OpcodeShortConditionalJmp,
 144     Soft386OpcodeShortConditionalJmp,
 145     Soft386OpcodeShortConditionalJmp,
 146     Soft386OpcodeShortConditionalJmp,
 147     Soft386OpcodeShortConditionalJmp,
 148     Soft386OpcodeShortConditionalJmp,
 149     Soft386OpcodeShortConditionalJmp,
 150     Soft386OpcodeShortConditionalJmp,
 151     Soft386OpcodeShortConditionalJmp,
 152     Soft386OpcodeShortConditionalJmp,
 153     Soft386OpcodeShortConditionalJmp,
 154     Soft386OpcodeShortConditionalJmp,
 155     NULL, // TODO: OPCODE 0x80 NOT SUPPORTED
 156     NULL, // TODO: OPCODE 0x81 NOT SUPPORTED
 157     NULL, // TODO: OPCODE 0x82 NOT SUPPORTED
 158     NULL, // TODO: OPCODE 0x83 NOT SUPPORTED
 159     NULL, // TODO: OPCODE 0x84 NOT SUPPORTED
 160     NULL, // TODO: OPCODE 0x85 NOT SUPPORTED
 161     NULL, // TODO: OPCODE 0x86 NOT SUPPORTED
 162     NULL, // TODO: OPCODE 0x87 NOT SUPPORTED
 163     NULL, // TODO: OPCODE 0x88 NOT SUPPORTED
 164     NULL, // TODO: OPCODE 0x89 NOT SUPPORTED
 165     NULL, // TODO: OPCODE 0x8A NOT SUPPORTED
 166     NULL, // TODO: OPCODE 0x8B NOT SUPPORTED
 167     NULL, // TODO: OPCODE 0x8C NOT SUPPORTED
 168     NULL, // TODO: OPCODE 0x8D NOT SUPPORTED
 169     NULL, // TODO: OPCODE 0x8E NOT SUPPORTED
 170     NULL, // TODO: OPCODE 0x8F NOT SUPPORTED
 171     Soft386OpcodeNop,
 172     Soft386OpcodeExchangeEax,
 173     Soft386OpcodeExchangeEax,
 174     Soft386OpcodeExchangeEax,
 175     Soft386OpcodeExchangeEax,
 176     Soft386OpcodeExchangeEax,
 177     Soft386OpcodeExchangeEax,
 178     Soft386OpcodeExchangeEax,
 179     NULL, // TODO: OPCODE 0x98 NOT SUPPORTED
 180     NULL, // TODO: OPCODE 0x99 NOT SUPPORTED
 181     NULL, // TODO: OPCODE 0x9A NOT SUPPORTED
 182     NULL, // TODO: OPCODE 0x9B NOT SUPPORTED
 183     NULL, // TODO: OPCODE 0x9C NOT SUPPORTED
 184     NULL, // TODO: OPCODE 0x9D NOT SUPPORTED
 185     NULL, // TODO: OPCODE 0x9E NOT SUPPORTED
 186     NULL, // TODO: OPCODE 0x9F NOT SUPPORTED
 187     NULL, // TODO: OPCODE 0xA0 NOT SUPPORTED
 188     NULL, // TODO: OPCODE 0xA1 NOT SUPPORTED
 189     NULL, // TODO: OPCODE 0xA2 NOT SUPPORTED
 190     NULL, // TODO: OPCODE 0xA3 NOT SUPPORTED
 191     NULL, // TODO: OPCODE 0xA4 NOT SUPPORTED
 192     NULL, // TODO: OPCODE 0xA5 NOT SUPPORTED
 193     NULL, // TODO: OPCODE 0xA6 NOT SUPPORTED
 194     NULL, // TODO: OPCODE 0xA7 NOT SUPPORTED
 195     NULL, // TODO: OPCODE 0xA8 NOT SUPPORTED
 196     NULL, // TODO: OPCODE 0xA9 NOT SUPPORTED
 197     NULL, // TODO: OPCODE 0xAA NOT SUPPORTED
 198     NULL, // TODO: OPCODE 0xAB NOT SUPPORTED
 199     NULL, // TODO: OPCODE 0xAC NOT SUPPORTED
 200     NULL, // TODO: OPCODE 0xAD NOT SUPPORTED
 201     NULL, // TODO: OPCODE 0xAE NOT SUPPORTED
 202     NULL, // TODO: OPCODE 0xAF NOT SUPPORTED
 203     NULL, // TODO: OPCODE 0xB0 NOT SUPPORTED
 204     NULL, // TODO: OPCODE 0xB1 NOT SUPPORTED
 205     NULL, // TODO: OPCODE 0xB2 NOT SUPPORTED
 206     NULL, // TODO: OPCODE 0xB3 NOT SUPPORTED
 207     NULL, // TODO: OPCODE 0xB4 NOT SUPPORTED
 208     NULL, // TODO: OPCODE 0xB5 NOT SUPPORTED
 209     NULL, // TODO: OPCODE 0xB6 NOT SUPPORTED
 210     NULL, // TODO: OPCODE 0xB7 NOT SUPPORTED
 211     NULL, // TODO: OPCODE 0xB8 NOT SUPPORTED
 212     NULL, // TODO: OPCODE 0xB9 NOT SUPPORTED
 213     NULL, // TODO: OPCODE 0xBA NOT SUPPORTED
 214     NULL, // TODO: OPCODE 0xBB NOT SUPPORTED
 215     NULL, // TODO: OPCODE 0xBC NOT SUPPORTED
 216     NULL, // TODO: OPCODE 0xBD NOT SUPPORTED
 217     NULL, // TODO: OPCODE 0xBE NOT SUPPORTED
 218     NULL, // TODO: OPCODE 0xBF NOT SUPPORTED
 219     NULL, // TODO: OPCODE 0xC0 NOT SUPPORTED
 220     NULL, // TODO: OPCODE 0xC1 NOT SUPPORTED
 221     NULL, // TODO: OPCODE 0xC2 NOT SUPPORTED
 222     NULL, // TODO: OPCODE 0xC3 NOT SUPPORTED
 223     NULL, // TODO: OPCODE 0xC4 NOT SUPPORTED
 224     NULL, // TODO: OPCODE 0xC5 NOT SUPPORTED
 225     NULL, // TODO: OPCODE 0xC6 NOT SUPPORTED
 226     NULL, // TODO: OPCODE 0xC7 NOT SUPPORTED
 227     NULL, // TODO: OPCODE 0xC8 NOT SUPPORTED
 228     NULL, // TODO: OPCODE 0xC9 NOT SUPPORTED
 229     NULL, // TODO: OPCODE 0xCA NOT SUPPORTED
 230     NULL, // TODO: OPCODE 0xCB NOT SUPPORTED
 231     NULL, // TODO: OPCODE 0xCC NOT SUPPORTED
 232     NULL, // TODO: OPCODE 0xCD NOT SUPPORTED
 233     NULL, // TODO: OPCODE 0xCE NOT SUPPORTED
 234     NULL, // TODO: OPCODE 0xCF NOT SUPPORTED
 235     NULL, // TODO: OPCODE 0xD0 NOT SUPPORTED
 236     NULL, // TODO: OPCODE 0xD1 NOT SUPPORTED
 237     NULL, // TODO: OPCODE 0xD2 NOT SUPPORTED
 238     NULL, // TODO: OPCODE 0xD3 NOT SUPPORTED
 239     NULL, // TODO: OPCODE 0xD4 NOT SUPPORTED
 240     NULL, // TODO: OPCODE 0xD5 NOT SUPPORTED
 241     NULL, // TODO: OPCODE 0xD6 NOT SUPPORTED
 242     NULL, // TODO: OPCODE 0xD7 NOT SUPPORTED
 243     NULL, // TODO: OPCODE 0xD8 NOT SUPPORTED
 244     NULL, // TODO: OPCODE 0xD9 NOT SUPPORTED
 245     NULL, // TODO: OPCODE 0xDA NOT SUPPORTED
 246     NULL, // TODO: OPCODE 0xDB NOT SUPPORTED
 247     NULL, // TODO: OPCODE 0xDC NOT SUPPORTED
 248     NULL, // TODO: OPCODE 0xDD NOT SUPPORTED
 249     NULL, // TODO: OPCODE 0xDE NOT SUPPORTED
 250     NULL, // TODO: OPCODE 0xDF NOT SUPPORTED
 251     NULL, // TODO: OPCODE 0xE0 NOT SUPPORTED
 252     NULL, // TODO: OPCODE 0xE1 NOT SUPPORTED
 253     NULL, // TODO: OPCODE 0xE2 NOT SUPPORTED
 254     NULL, // TODO: OPCODE 0xE3 NOT SUPPORTED
 255     NULL, // TODO: OPCODE 0xE4 NOT SUPPORTED
 256     NULL, // TODO: OPCODE 0xE5 NOT SUPPORTED
 257     NULL, // TODO: OPCODE 0xE6 NOT SUPPORTED
 258     NULL, // TODO: OPCODE 0xE7 NOT SUPPORTED
 259     NULL, // TODO: OPCODE 0xE8 NOT SUPPORTED
 260     NULL, // TODO: OPCODE 0xE9 NOT SUPPORTED
 261     NULL, // TODO: OPCODE 0xEA NOT SUPPORTED
 262     NULL, // TODO: OPCODE 0xEB NOT SUPPORTED
 263     NULL, // TODO: OPCODE 0xEC NOT SUPPORTED
 264     NULL, // TODO: OPCODE 0xED NOT SUPPORTED
 265     NULL, // TODO: OPCODE 0xEE NOT SUPPORTED
 266     NULL, // TODO: OPCODE 0xEF NOT SUPPORTED
 267     Soft386OpcodePrefix,
 268     NULL, // Invalid
 269     Soft386OpcodePrefix,
 270     Soft386OpcodePrefix,
 271     NULL, // TODO: OPCODE 0xF4 NOT SUPPORTED
 272     NULL, // TODO: OPCODE 0xF5 NOT SUPPORTED
 273     NULL, // TODO: OPCODE 0xF6 NOT SUPPORTED
 274     NULL, // TODO: OPCODE 0xF7 NOT SUPPORTED
 275     Soft386OpcodeClearCarry,
 276     Soft386OpcodeSetCarry,
 277     Soft386OpcodeClearInt,
 278     Soft386OpcodeSetInt,
 279     Soft386OpcodeClearDir,
 280     Soft386OpcodeSetDir,
 281     NULL, // TODO: OPCODE 0xFE NOT SUPPORTED
 282     NULL, // TODO: OPCODE 0xFF NOT SUPPORTED
 283 };
 284
 285 BOOLEAN
 286 FASTCALL
 287 Soft386OpcodePrefix(PSOFT386_STATE State, UCHAR Opcode)
 288 {
 289     BOOLEAN Valid = FALSE;
 290
 291     switch (Opcode)
 292     {
 293         /* ES: */
 294         case 0x26:
 295         {
 296             if (!(State->PrefixFlags & SOFT386_PREFIX_SEG))
 297             {
 298                 State->PrefixFlags |= SOFT386_PREFIX_SEG;
 299                 State->SegmentOverride = SOFT386_REG_ES;
 300                 Valid = TRUE;
 301             }
 302
 303             break;
 304         }
 305
 306         /* CS: */
 307         case 0x2E:
 308         {
 309             if (!(State->PrefixFlags & SOFT386_PREFIX_SEG))
 310             {
 311                 State->PrefixFlags |= SOFT386_PREFIX_SEG;
 312                 State->SegmentOverride = SOFT386_REG_CS;
 313                 Valid = TRUE;
 314             }
 315
 316             break;
 317         }
 318
 319         /* SS: */
 320         case 0x36:
 321         {
 322             if (!(State->PrefixFlags & SOFT386_PREFIX_SEG))
 323             {
 324                 State->PrefixFlags |= SOFT386_PREFIX_SEG;
 325                 State->SegmentOverride = SOFT386_REG_SS;
 326                 Valid = TRUE;
 327             }
 328
 329             break;
 330         }
 331
 332         /* DS: */
 333         case 0x3E:
 334         {
 335             if (!(State->PrefixFlags & SOFT386_PREFIX_SEG))
 336             {
 337                 State->PrefixFlags |= SOFT386_PREFIX_SEG;
 338                 State->SegmentOverride = SOFT386_REG_DS;
 339                 Valid = TRUE;
 340             }
 341
 342             break;
 343         }
 344
 345         /* FS: */
 346         case 0x64:
 347         {
 348             if (!(State->PrefixFlags & SOFT386_PREFIX_SEG))
 349             {
 350                 State->PrefixFlags |= SOFT386_PREFIX_SEG;
 351                 State->SegmentOverride = SOFT386_REG_FS;
 352                 Valid = TRUE;
 353             }
 354
 355             break;
 356         }
 357
 358         /* GS: */
 359         case 0x65:
 360         {
 361             if (!(State->PrefixFlags & SOFT386_PREFIX_SEG))
 362             {
 363                 State->PrefixFlags |= SOFT386_PREFIX_SEG;
 364                 State->SegmentOverride = SOFT386_REG_GS;
 365                 Valid = TRUE;
 366             }
 367
 368             break;
 369         }
 370
 371         /* OPSIZE */
 372         case 0x66:
 373         {
 374             if (!(State->PrefixFlags & SOFT386_PREFIX_OPSIZE))
 375             {
 376                 State->PrefixFlags |= SOFT386_PREFIX_OPSIZE;
 377                 Valid = TRUE;
 378             }
 379
 380             break;
 381         }
 382
 383         /* ADSIZE */
 384         case 0x67:
 385         {
 386             if (!(State->PrefixFlags & SOFT386_PREFIX_ADSIZE))
 387             {
 388                 State->PrefixFlags |= SOFT386_PREFIX_ADSIZE;
 389                 Valid = TRUE;
 390             }
 391             break;
 392         }
 393
 394         /* LOCK */
 395         case 0xF0:
 396         {
 397             if (!(State->PrefixFlags & SOFT386_PREFIX_LOCK))
 398             {
 399                 State->PrefixFlags |= SOFT386_PREFIX_LOCK;
 400                 Valid = TRUE;
 401             }
 402
 403             break;
 404         }
 405
 406         /* REPNZ */
 407         case 0xF2:
 408         {
 409             /* Mutually exclusive with REP */
 410             if (!(State->PrefixFlags
 411                 & (SOFT386_PREFIX_REPNZ | SOFT386_PREFIX_REP)))
 412             {
 413                 State->PrefixFlags |= SOFT386_PREFIX_REPNZ;
 414                 Valid = TRUE;
 415             }
 416
 417             break;
 418         }
 419
 420         /* REP / REPZ */
 421         case 0xF3:
 422         {
 423             /* Mutually exclusive with REPNZ */
 424             if (!(State->PrefixFlags
 425                 & (SOFT386_PREFIX_REPNZ | SOFT386_PREFIX_REP)))
 426             {
 427                 State->PrefixFlags |= SOFT386_PREFIX_REP;
 428                 Valid = TRUE;
 429             }
 430
 431             break;
 432         }
 433     }
 434
 435     if (!Valid)
 436     {
 437         /* Clear all prefixes */
 438         State->PrefixFlags = 0;
 439
 440         /* Throw an exception */
 441         Soft386Exception(State, SOFT386_EXCEPTION_UD);
 442         return FALSE;
 443     }
 444
 445     return TRUE;
 446 }
 447
 448 BOOLEAN
 449 FASTCALL
 450 Soft386OpcodeIncrement(PSOFT386_STATE State, UCHAR Opcode)
 451 {
 452     ULONG Value;
 453     BOOLEAN Size = State->SegmentRegs[SOFT386_REG_CS].Size;
 454
 455     if (State->PrefixFlags == SOFT386_PREFIX_OPSIZE)
 456     {
 457         /* The OPSIZE prefix toggles the size */
 458         Size = !Size;
 459     }
 460     else if (State->PrefixFlags != 0)
 461     {
 462         /* Invalid prefix */
 463         Soft386Exception(State, SOFT386_EXCEPTION_UD);
 464         return FALSE;
 465     }
 466
 467     /* Make sure this is the right instruction */
 468     ASSERT((Opcode & 0xF8) == 0x40);
 469
 470     if (Size)
 471     {
 472         Value = ++State->GeneralRegs[Opcode & 0x07].Long;
 473
 474         State->Flags.Of = (Value == SIGN_FLAG_LONG) ? TRUE : FALSE;
 475         State->Flags.Sf = (Value & SIGN_FLAG_LONG) ? TRUE : FALSE;
 476     }
 477     else
 478     {
 479         Value = ++State->GeneralRegs[Opcode & 0x07].LowWord;
 480
 481         State->Flags.Of = (Value == SIGN_FLAG_WORD) ? TRUE : FALSE;
 482         State->Flags.Sf = (Value & SIGN_FLAG_WORD) ? TRUE : FALSE;
 483     }
 484
 485     State->Flags.Zf = (Value == 0) ? TRUE : FALSE;
 486     State->Flags.Af = ((Value & 0x0F) == 0) ? TRUE : FALSE;
 487     State->Flags.Pf = Soft386CalculateParity(LOBYTE(Value));
 488
 489     /* Return success */
 490     return TRUE;
 491 }
 492
 493 BOOLEAN
 494 FASTCALL
 495 Soft386OpcodeDecrement(PSOFT386_STATE State, UCHAR Opcode)
 496 {
 497     ULONG Value;
 498     BOOLEAN Size = State->SegmentRegs[SOFT386_REG_CS].Size;
 499
 500     if (State->PrefixFlags == SOFT386_PREFIX_OPSIZE)
 501     {
 502         /* The OPSIZE prefix toggles the size */
 503         Size = !Size;
 504     }
 505     else if (State->PrefixFlags != 0)
 506     {
 507         /* Invalid prefix */
 508         Soft386Exception(State, SOFT386_EXCEPTION_UD);
 509         return FALSE;
 510     }
 511
 512     /* Make sure this is the right instruction */
 513     ASSERT((Opcode & 0xF8) == 0x48);
 514
 515     if (Size)
 516     {
 517         Value = --State->GeneralRegs[Opcode & 0x07].Long;
 518
 519         State->Flags.Of = (Value == (SIGN_FLAG_LONG - 1)) ? TRUE : FALSE;
 520         State->Flags.Sf = (Value & SIGN_FLAG_LONG) ? TRUE : FALSE;
 521     }
 522     else
 523     {
 524         Value = --State->GeneralRegs[Opcode & 0x07].LowWord;
 525
 526         State->Flags.Of = (Value == (SIGN_FLAG_WORD - 1)) ? TRUE : FALSE;
 527         State->Flags.Sf = (Value & SIGN_FLAG_WORD) ? TRUE : FALSE;
 528     }
 529
 530     State->Flags.Zf = (Value == 0) ? TRUE : FALSE;
 531     State->Flags.Af = ((Value & 0x0F) == 0x0F) ? TRUE : FALSE;
 532     State->Flags.Pf = Soft386CalculateParity(LOBYTE(Value));
 533
 534     /* Return success */
 535     return TRUE;
 536 }
 537
 538 BOOLEAN
 539 FASTCALL
 540 Soft386OpcodePushReg(PSOFT386_STATE State, UCHAR Opcode)
 541 {
 542     if ((State->PrefixFlags != SOFT386_PREFIX_OPSIZE)
 543         && (State->PrefixFlags != 0))
 544     {
 545         /* Invalid prefix */
 546         Soft386Exception(State, SOFT386_EXCEPTION_UD);
 547         return FALSE;
 548     }
 549
 550     /* Make sure this is the right instruction */
 551     ASSERT((Opcode & 0xF8) == 0x50);
 552
 553     /* Call the internal function */
 554     return Soft386StackPush(State, State->GeneralRegs[Opcode & 0x07].Long);
 555 }
 556
 557 BOOLEAN
 558 FASTCALL
 559 Soft386OpcodePopReg(PSOFT386_STATE State, UCHAR Opcode)
 560 {
 561     ULONG Value;
 562     BOOLEAN Size = State->SegmentRegs[SOFT386_REG_SS].Size;
 563
 564     if (State->PrefixFlags == SOFT386_PREFIX_OPSIZE)
 565     {
 566         /* The OPSIZE prefix toggles the size */
 567         Size = !Size;
 568     }
 569     else if (State->PrefixFlags != 0)
 570     {
 571         /* Invalid prefix */
 572         Soft386Exception(State, SOFT386_EXCEPTION_UD);
 573         return FALSE;
 574     }
 575
 576     /* Make sure this is the right instruction */
 577     ASSERT((Opcode & 0xF8) == 0x58);
 578
 579     /* Call the internal function */
 580     if (!Soft386StackPop(State, &Value)) return FALSE;
 581
 582     /* Store the value */
 583     if (Size) State->GeneralRegs[Opcode & 0x07].Long = Value;
 584     else State->GeneralRegs[Opcode & 0x07].LowWord = Value;
 585
 586     /* Return success */
 587     return TRUE;
 588 }
 589
 590 BOOLEAN
 591 FASTCALL
 592 Soft386OpcodeNop(PSOFT386_STATE State, UCHAR Opcode)
 593 {
 594     if (State->PrefixFlags & ~(SOFT386_PREFIX_OPSIZE | SOFT386_PREFIX_REP))
 595     {
 596         /* Allowed prefixes are REP and OPSIZE */
 597         Soft386Exception(State, SOFT386_EXCEPTION_UD);
 598         return FALSE;
 599     }
 600
 601     if (State->PrefixFlags & SOFT386_PREFIX_REP)
 602     {
 603         /* Idle cycle */
 604         State->IdleCallback(State);
 605     }
 606
 607     return TRUE;
 608 }
 609
 610 BOOLEAN
 611 FASTCALL
 612 Soft386OpcodeExchangeEax(PSOFT386_STATE State, UCHAR Opcode)
 613 {
 614     INT Reg = Opcode & 0x07;
 615     BOOLEAN Size = State->SegmentRegs[SOFT386_REG_CS].Size;
 616
 617     if (State->PrefixFlags == SOFT386_PREFIX_OPSIZE)
 618     {
 619         /* The OPSIZE prefix toggles the size */
 620         Size = !Size;
 621     }
 622     else if (State->PrefixFlags != 0)
 623     {
 624         /* Invalid prefix */
 625         Soft386Exception(State, SOFT386_EXCEPTION_UD);
 626         return FALSE;
 627     }
 628
 629     /* Make sure this is the right instruction */
 630     ASSERT((Opcode & 0xF8) == 0x90);
 631
 632     /* Exchange the values */
 633     if (Size)
 634     {
 635         ULONG Value;
 636
 637         Value = State->GeneralRegs[Reg].Long;
 638         State->GeneralRegs[Reg].Long = State->GeneralRegs[SOFT386_REG_EAX].Long;
 639         State->GeneralRegs[SOFT386_REG_EAX].Long = Value;
 640     }
 641     else
 642     {
 643         USHORT Value;
 644
 645         Value = State->GeneralRegs[Reg].LowWord;
 646         State->GeneralRegs[Reg].LowWord = State->GeneralRegs[SOFT386_REG_EAX].LowWord;
 647         State->GeneralRegs[SOFT386_REG_EAX].LowWord = Value;
 648     }
 649
 650     return TRUE;
 651 }
 652
 653 BOOLEAN
 654 FASTCALL
 655 Soft386OpcodeShortConditionalJmp(PSOFT386_STATE State, UCHAR Opcode)
 656 {
 657     BOOLEAN Jump = FALSE;
 658     CHAR Offset = 0;
 659
 660     /* Make sure this is the right instruction */
 661     ASSERT((Opcode & 0xF0) == 0x70);
 662
 663     /* Fetch the offset */
 664     if (!Soft386FetchByte(State, (PUCHAR)&Offset))
 665     {
 666         /* An exception occurred */
 667         return FALSE;
 668     }
 669
 670     switch ((Opcode & 0x0F) >> 1)
 671     {
 672         /* JO / JNO */
 673         case 0:
 674         {
 675             Jump = State->Flags.Of;
 676             break;
 677         }
 678
 679         /* JC / JNC */
 680         case 1:
 681         {
 682             Jump = State->Flags.Cf;
 683             break;
 684         }
 685
 686         /* JZ / JNZ */
 687         case 2:
 688         {
 689             Jump = State->Flags.Zf;
 690             break;
 691         }
 692
 693         /* JBE / JNBE */
 694         case 3:
 695         {
 696             Jump = State->Flags.Cf || State->Flags.Zf;
 697             break;
 698         }
 699
 700         /* JS / JNS */
 701         case 4:
 702         {
 703             Jump = State->Flags.Sf;
 704             break;
 705         }
 706
 707         /* JP / JNP */
 708         case 5:
 709         {
 710             Jump = State->Flags.Pf;
 711             break;
 712         }
 713
 714         /* JL / JNL */
 715         case 6:
 716         {
 717             Jump = State->Flags.Sf != State->Flags.Of;
 718             break;
 719         }
 720
 721         /* JLE / JNLE */
 722         case 7:
 723         {
 724             Jump = (State->Flags.Sf != State->Flags.Of) || State->Flags.Zf;
 725             break;
 726         }
 727     }
 728
 729     if ((Opcode & 0xF0) & 1)
 730     {
 731         /* Invert the result */
 732         Jump = !Jump;
 733     }
 734
 735     if (Jump)
 736     {
 737         /* Move the instruction pointer */
 738         State->InstPtr.Long += Offset;
 739     }
 740
 741     /* Return success */
 742     return TRUE;
 743 }
 744
 745 BOOLEAN
 746 FASTCALL
 747 Soft386OpcodeClearCarry(PSOFT386_STATE State, UCHAR Opcode)
 748 {
 749     /* Make sure this is the right instruction */
 750     ASSERT(Opcode == 0xF8);
 751
 752     /* No prefixes allowed */
 753     if (State->PrefixFlags)
 754     {
 755         Soft386Exception(State, SOFT386_EXCEPTION_UD);
 756         return FALSE;
 757     }
 758
 759     /* Clear CF and return success */
 760     State->Flags.Cf = FALSE;
 761     return TRUE;
 762 }
 763
 764 BOOLEAN
 765 FASTCALL
 766 Soft386OpcodeSetCarry(PSOFT386_STATE State, UCHAR Opcode)
 767 {
 768     /* Make sure this is the right instruction */
 769     ASSERT(Opcode == 0xF9);
 770
 771     /* No prefixes allowed */
 772     if (State->PrefixFlags)
 773     {
 774         Soft386Exception(State, SOFT386_EXCEPTION_UD);
 775         return FALSE;
 776     }
 777
 778     /* Set CF and return success*/
 779     State->Flags.Cf = TRUE;
 780     return TRUE;
 781 }
 782
 783 BOOLEAN
 784 FASTCALL
 785 Soft386OpcodeClearInt(PSOFT386_STATE State, UCHAR Opcode)
 786 {
 787     /* Make sure this is the right instruction */
 788     ASSERT(Opcode == 0xFA);
 789
 790     /* No prefixes allowed */
 791     if (State->PrefixFlags)
 792     {
 793         Soft386Exception(State, SOFT386_EXCEPTION_UD);
 794         return FALSE;
 795     }
 796
 797     /* Check for protected mode */
 798     if (State->ControlRegisters[SOFT386_REG_CR0] & SOFT386_CR0_PE)
 799     {
 800         /* Check IOPL */
 801         if (State->Flags.Iopl >= State->SegmentRegs[SOFT386_REG_CS].Dpl)
 802         {
 803             /* Clear the interrupt flag */
 804             State->Flags.If = FALSE;
 805         }
 806         else
 807         {
 808             /* General Protection Fault */
 809             Soft386Exception(State, SOFT386_EXCEPTION_GP);
 810             return FALSE;
 811         }
 812     }
 813     else
 814     {
 815         /* Just clear the interrupt flag */
 816         State->Flags.If = FALSE;
 817     }
 818
 819     /* Return success */
 820     return TRUE;
 821 }
 822
 823 BOOLEAN
 824 FASTCALL
 825 Soft386OpcodeSetInt(PSOFT386_STATE State, UCHAR Opcode)
 826 {
 827     /* Make sure this is the right instruction */
 828     ASSERT(Opcode == 0xFB);
 829
 830     /* No prefixes allowed */
 831     if (State->PrefixFlags)
 832     {
 833         Soft386Exception(State, SOFT386_EXCEPTION_UD);
 834         return FALSE;
 835     }
 836
 837     /* Check for protected mode */
 838     if (State->ControlRegisters[SOFT386_REG_CR0] & SOFT386_CR0_PE)
 839     {
 840         /* Check IOPL */
 841         if (State->Flags.Iopl >= State->SegmentRegs[SOFT386_REG_CS].Dpl)
 842         {
 843             /* Set the interrupt flag */
 844             State->Flags.If = TRUE;
 845         }
 846         else
 847         {
 848             /* General Protection Fault */
 849             Soft386Exception(State, SOFT386_EXCEPTION_GP);
 850             return FALSE;
 851         }
 852     }
 853     else
 854     {
 855         /* Just set the interrupt flag */
 856         State->Flags.If = TRUE;
 857     }
 858
 859     /* Return success */
 860     return TRUE;
 861 }
 862
 863 BOOLEAN
 864 FASTCALL
 865 Soft386OpcodeClearDir(PSOFT386_STATE State, UCHAR Opcode)
 866 {
 867     /* Make sure this is the right instruction */
 868     ASSERT(Opcode == 0xFC);
 869
 870     /* No prefixes allowed */
 871     if (State->PrefixFlags)
 872     {
 873         Soft386Exception(State, SOFT386_EXCEPTION_UD);
 874         return FALSE;
 875     }
 876
 877     /* Clear DF and return success */
 878     State->Flags.Df = FALSE;
 879     return TRUE;
 880 }
 881
 882 BOOLEAN
 883 FASTCALL
 884 Soft386OpcodeSetDir(PSOFT386_STATE State, UCHAR Opcode)
 885 {
 886     /* Make sure this is the right instruction */
 887     ASSERT(Opcode == 0xFD);
 888
 889     /* No prefixes allowed */
 890     if (State->PrefixFlags)
 891     {
 892         Soft386Exception(State, SOFT386_EXCEPTION_UD);
 893         return FALSE;
 894     }
 895
 896     /* Set DF and return success*/
 897     State->Flags.Df = TRUE;
 898     return TRUE;
 899 }
 900
 901 BOOLEAN
 902 FASTCALL
 903 Soft386OpcodeHalt(PSOFT386_STATE State, UCHAR Opcode)
 904 {
 905     /* Make sure this is the right instruction */
 906     ASSERT(Opcode == 0xF4);
 907
 908     /* No prefixes allowed */
 909     if (State->PrefixFlags)
 910     {
 911         Soft386Exception(State, SOFT386_EXCEPTION_UD);
 912         return FALSE;
 913     }
 914
 915     /* Privileged instructions can only be executed under CPL = 0 */
 916     if (State->SegmentRegs[SOFT386_REG_CS].Dpl != 0)
 917     {
 918         Soft386Exception(State, SOFT386_EXCEPTION_GP);
 919         return FALSE;
 920     }
 921
 922     /* Halt */
 923     while (!State->HardwareInt) State->IdleCallback(State);
 924
 925     /* Return success */
 926     return TRUE;
 927 }