reactos/lib/fast486/opgroups.c

   1 /*
   2  * Fast486 386/486 CPU Emulation Library
   3  * opgroups.c
   4  *
   5  * Copyright (C) 2014 Aleksandar Andrejevic <theflash AT sdf DOT lonestar DOT org>
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License
   9  * as published by the Free Software Foundation; either version 2
  10  * of the License, or (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  20  */
  21
  22 /* INCLUDES *******************************************************************/
  23
  24 #include <windef.h>
  25
  26 // #define NDEBUG
  27 #include <debug.h>
  28
  29 #include <fast486.h>
  30 #include "opcodes.h"
  31 #include "common.h"
  32
  33 /* PRIVATE FUNCTIONS **********************************************************/
  34
  35 static
  36 inline
  37 ULONG
  38 Fast486ArithmeticOperation(PFAST486_STATE State,
  39                            INT Operation,
  40                            ULONG FirstValue,
  41                            ULONG SecondValue,
  42                            UCHAR Bits)
  43 {
  44     ULONG Result;
  45     ULONG SignFlag = 1 << (Bits - 1);
  46     ULONG MaxValue = (SignFlag - 1) | SignFlag;
  47
  48     /* Make sure the values don't exceed the maximum for their size */
  49     FirstValue &= MaxValue;
  50     SecondValue &= MaxValue;
  51
  52     /* Check which operation is this */
  53     switch (Operation)
  54     {
  55         /* ADD */
  56         case 0:
  57         {
  58             Result = (FirstValue + SecondValue) & MaxValue;
  59
  60             /* Update CF, OF and AF */
  61             State->Flags.Cf = (Result < FirstValue) && (Result < SecondValue);
  62             State->Flags.Of = ((FirstValue & SignFlag) == (SecondValue & SignFlag))
  63                               && ((FirstValue & SignFlag) != (Result & SignFlag));
  64             State->Flags.Af = ((((FirstValue & 0x0F) + (SecondValue & 0x0F)) & 0x10) != 0);
  65
  66             break;
  67         }
  68
  69         /* OR */
  70         case 1:
  71         {
  72             Result = FirstValue | SecondValue;
  73             break;
  74         }
  75
  76         /* ADC */
  77         case 2:
  78         {
  79             INT Carry = State->Flags.Cf ? 1 : 0;
  80
  81             Result = (FirstValue + SecondValue + Carry) & MaxValue;
  82
  83             /* Update CF, OF and AF */
  84             State->Flags.Cf = ((SecondValue == MaxValue) && (Carry == 1))
  85                               || ((Result < FirstValue) && (Result < (SecondValue + Carry)));
  86             State->Flags.Of = ((FirstValue & SignFlag) == (SecondValue & SignFlag))
  87                               && ((FirstValue & SignFlag) != (Result & SignFlag));
  88             State->Flags.Af = ((FirstValue ^ SecondValue ^ Result) & 0x10) != 0;
  89
  90             break;
  91         }
  92
  93         /* SBB */
  94         case 3:
  95         {
  96             INT Carry = State->Flags.Cf ? 1 : 0;
  97
  98             Result = (FirstValue - SecondValue - Carry) & MaxValue;
  99
 100             /* Update CF, OF and AF */
 101             State->Flags.Cf = Carry
 102                               ? (FirstValue <= SecondValue)
 103                               : (FirstValue < SecondValue);
 104             State->Flags.Of = ((FirstValue & SignFlag) != (SecondValue & SignFlag))
 105                               && ((FirstValue & SignFlag) != (Result & SignFlag));
 106             State->Flags.Af = ((FirstValue ^ SecondValue ^ Result) & 0x10) != 0;
 107
 108             break;
 109         }
 110
 111         /* AND */
 112         case 4:
 113         {
 114             Result = FirstValue & SecondValue;
 115             break;
 116         }
 117
 118         /* SUB or CMP */
 119         case 5:
 120         case 7:
 121         {
 122             Result = (FirstValue - SecondValue) & MaxValue;
 123
 124             /* Update CF, OF and AF */
 125             State->Flags.Cf = (FirstValue < SecondValue);
 126             State->Flags.Of = ((FirstValue & SignFlag) != (SecondValue & SignFlag))
 127                               && ((FirstValue & SignFlag) != (Result & SignFlag));
 128             State->Flags.Af = (FirstValue & 0x0F) < (SecondValue & 0x0F);
 129
 130             break;
 131         }
 132
 133         /* XOR */
 134         case 6:
 135         {
 136             Result = FirstValue ^ SecondValue;
 137             break;
 138         }
 139
 140         default:
 141         {
 142             /* Shouldn't happen */
 143             ASSERT(FALSE);
 144         }
 145     }
 146
 147     /* Update ZF, SF and PF */
 148     State->Flags.Zf = (Result == 0);
 149     State->Flags.Sf = ((Result & SignFlag) != 0);
 150     State->Flags.Pf = Fast486CalculateParity(LOBYTE(Result));
 151
 152     /* Return the result */
 153     return Result;
 154 }
 155
 156 static
 157 inline
 158 ULONG
 159 Fast486RotateOperation(PFAST486_STATE State,
 160                        INT Operation,
 161                        ULONG Value,
 162                        UCHAR Bits,
 163                        UCHAR Count)
 164 {
 165     ULONG HighestBit = 1 << (Bits - 1);
 166     ULONG MaxValue = HighestBit | (HighestBit - 1);
 167     ULONG Result;
 168
 169     /* Normalize the count */
 170     Count &= 0x1F;
 171
 172     if ((Operation == 2) || (Operation == 3)) Count %= Bits + 1;
 173
 174     /* If the count is zero, do nothing */
 175     if (Count == 0) return Value;
 176
 177     /* Check which operation is this */
 178     switch (Operation)
 179     {
 180         /* ROL */
 181         case 0:
 182         {
 183             Count %= Bits;
 184             Result = (Value << Count) | (Value >> (Bits - Count));
 185
 186             /* Update CF and OF */
 187             State->Flags.Cf = Result & 1;
 188             if (Count == 1) State->Flags.Of = State->Flags.Cf
 189                                               ^ ((Result & HighestBit) != 0);
 190
 191             break;
 192         }
 193
 194         /* ROR */
 195         case 1:
 196         {
 197             Count %= Bits;
 198             Result = (Value >> Count) | (Value << (Bits - Count));
 199
 200             /* Update CF and OF */
 201             State->Flags.Cf = ((Result & HighestBit) != 0);
 202             if (Count == 1) State->Flags.Of = State->Flags.Cf
 203                                               ^ ((Result & (HighestBit >> 1)) != 0);
 204
 205             break;
 206         }
 207
 208         /* RCL */
 209         case 2:
 210         {
 211             Result = (Value << Count) | (State->Flags.Cf << (Count - 1));
 212
 213             /* Complete the calculation, but make sure we don't shift by too much */
 214             if ((Bits - Count) < 31) Result |= Value >> (Bits - Count + 1);
 215
 216             /* Update CF and OF */
 217             State->Flags.Cf = ((Value & (1 << (Bits - Count))) != 0);
 218             if (Count == 1) State->Flags.Of = State->Flags.Cf ^ ((Result & HighestBit) != 0);
 219
 220             break;
 221         }
 222
 223         /* RCR */
 224         case 3:
 225         {
 226             /* Update OF */
 227             if (Count == 1) State->Flags.Of = State->Flags.Cf ^ ((Value & HighestBit) != 0);
 228
 229             Result = (Value >> Count) | (State->Flags.Cf << (Bits - Count));
 230
 231             /* Complete the calculation, but make sure we don't shift by too much */
 232             if ((Bits - Count) < 31) Result |= Value << (Bits - Count + 1);
 233
 234             /* Update CF */
 235             State->Flags.Cf = ((Value & (1 << (Count - 1))) != 0);
 236
 237             break;
 238         }
 239
 240         /* SHL/SAL */
 241         case 4:
 242         case 6:
 243         {
 244             Result = Value << Count;
 245
 246             /* Update CF and OF */
 247             State->Flags.Cf = ((Value & (1 << (Bits - Count))) != 0);
 248             if (Count == 1) State->Flags.Of = State->Flags.Cf
 249                                               ^ ((Result & HighestBit) != 0);
 250
 251             break;
 252         }
 253
 254         /* SHR */
 255         case 5:
 256         {
 257             Result = Value >> Count;
 258
 259             /* Update CF and OF */
 260             State->Flags.Cf = ((Value & (1 << (Count - 1))) != 0);
 261             if (Count == 1) State->Flags.Of = ((Value & HighestBit) != 0);
 262
 263             break;
 264         }
 265
 266         /* SAR */
 267         case 7:
 268         {
 269             Result = Value >> Count;
 270
 271             /* Fill the top Count bits with the sign bit */
 272             if (Value & HighestBit) Result |= ((1 << Count) - 1) << (Bits - Count);
 273
 274             /* Update CF and OF */
 275             State->Flags.Cf = ((Value & (1 << (Count - 1))) != 0);
 276             if (Count == 1) State->Flags.Of = FALSE;
 277
 278             break;
 279         }
 280     }
 281
 282     if (Operation >= 4)
 283     {
 284         /* Update ZF, SF and PF */
 285         State->Flags.Zf = ((Result & MaxValue) == 0);
 286         State->Flags.Sf = ((Result & HighestBit) != 0);
 287         State->Flags.Pf = Fast486CalculateParity(Result);
 288     }
 289
 290     /* Return the result */
 291     return Result;
 292 }
 293
 294 /* PUBLIC FUNCTIONS ***********************************************************/
 295
 296 FAST486_OPCODE_HANDLER(Fast486OpcodeGroup8082)
 297 {
 298     UCHAR Immediate, Value;
 299     FAST486_MOD_REG_RM ModRegRm;
 300     BOOLEAN AddressSize = State->SegmentRegs[FAST486_REG_CS].Size;
 301
 302     TOGGLE_ADSIZE(AddressSize);
 303
 304     if (!Fast486ParseModRegRm(State, AddressSize, &ModRegRm))
 305     {
 306         /* Exception occurred */
 307         return;
 308     }
 309
 310     /* Fetch the immediate operand */
 311     if (!Fast486FetchByte(State, &Immediate))
 312     {
 313         /* Exception occurred */
 314         return;
 315     }
 316
 317     /* Read the operands */
 318     if (!Fast486ReadModrmByteOperands(State, &ModRegRm, NULL, &Value))
 319     {
 320         /* Exception occurred */
 321         return;
 322     }
 323
 324     /* Calculate the result */
 325     Value = Fast486ArithmeticOperation(State, ModRegRm.Register, Value, Immediate, 8);
 326
 327     /* Unless this is CMP, write back the result */
 328     if (ModRegRm.Register != 7)
 329     {
 330         Fast486WriteModrmByteOperands(State, &ModRegRm, FALSE, Value);
 331     }
 332 }
 333
 334 FAST486_OPCODE_HANDLER(Fast486OpcodeGroup81)
 335 {
 336     FAST486_MOD_REG_RM ModRegRm;
 337     BOOLEAN OperandSize, AddressSize;
 338
 339     OperandSize = AddressSize = State->SegmentRegs[FAST486_REG_CS].Size;
 340
 341     TOGGLE_OPSIZE(OperandSize);
 342     TOGGLE_ADSIZE(AddressSize);
 343
 344     if (!Fast486ParseModRegRm(State, AddressSize, &ModRegRm))
 345     {
 346         /* Exception occurred */
 347         return;
 348     }
 349
 350     if (OperandSize)
 351     {
 352         ULONG Immediate, Value;
 353
 354         /* Fetch the immediate operand */
 355         if (!Fast486FetchDword(State, &Immediate))
 356         {
 357             /* Exception occurred */
 358             return;
 359         }
 360
 361         /* Read the operands */
 362         if (!Fast486ReadModrmDwordOperands(State, &ModRegRm, NULL, &Value))
 363         {
 364             /* Exception occurred */
 365             return;
 366         }
 367
 368         /* Calculate the result */
 369         Value = Fast486ArithmeticOperation(State, ModRegRm.Register, Value, Immediate, 32);
 370
 371         /* Unless this is CMP, write back the result */
 372         if (ModRegRm.Register != 7)
 373         {
 374             Fast486WriteModrmDwordOperands(State, &ModRegRm, FALSE, Value);
 375         }
 376     }
 377     else
 378     {
 379         USHORT Immediate, Value;
 380
 381         /* Fetch the immediate operand */
 382         if (!Fast486FetchWord(State, &Immediate))
 383         {
 384             /* Exception occurred */
 385             return;
 386         }
 387
 388         /* Read the operands */
 389         if (!Fast486ReadModrmWordOperands(State, &ModRegRm, NULL, &Value))
 390         {
 391             /* Exception occurred */
 392             return;
 393         }
 394
 395         /* Calculate the result */
 396         Value = Fast486ArithmeticOperation(State, ModRegRm.Register, Value, Immediate, 16);
 397
 398         /* Unless this is CMP, write back the result */
 399         if (ModRegRm.Register != 7)
 400         {
 401             Fast486WriteModrmWordOperands(State, &ModRegRm, FALSE, Value);
 402         }
 403     }
 404 }
 405
 406 FAST486_OPCODE_HANDLER(Fast486OpcodeGroup83)
 407 {
 408     CHAR ImmByte;
 409     FAST486_MOD_REG_RM ModRegRm;
 410     BOOLEAN OperandSize, AddressSize;
 411
 412     OperandSize = AddressSize = State->SegmentRegs[FAST486_REG_CS].Size;
 413
 414     TOGGLE_OPSIZE(OperandSize);
 415     TOGGLE_ADSIZE(AddressSize);
 416
 417     if (!Fast486ParseModRegRm(State, AddressSize, &ModRegRm))
 418     {
 419         /* Exception occurred */
 420         return;
 421     }
 422
 423     /* Fetch the immediate operand */
 424     if (!Fast486FetchByte(State, (PUCHAR)&ImmByte))
 425     {
 426         /* Exception occurred */
 427         return;
 428     }
 429
 430     if (OperandSize)
 431     {
 432         ULONG Immediate = (ULONG)((LONG)ImmByte); // Sign extend
 433         ULONG Value;
 434
 435         /* Read the operands */
 436         if (!Fast486ReadModrmDwordOperands(State, &ModRegRm, NULL, &Value))
 437         {
 438             /* Exception occurred */
 439             return;
 440         }
 441
 442         /* Calculate the result */
 443         Value = Fast486ArithmeticOperation(State, ModRegRm.Register, Value, Immediate, 32);
 444
 445         /* Unless this is CMP, write back the result */
 446         if (ModRegRm.Register != 7)
 447         {
 448             Fast486WriteModrmDwordOperands(State, &ModRegRm, FALSE, Value);
 449         }
 450     }
 451     else
 452     {
 453         USHORT Immediate = (USHORT)((SHORT)ImmByte); // Sign extend
 454         USHORT Value;
 455
 456         /* Read the operands */
 457         if (!Fast486ReadModrmWordOperands(State, &ModRegRm, NULL, &Value))
 458         {
 459             /* Exception occurred */
 460             return;
 461         }
 462
 463         /* Calculate the result */
 464         Value = Fast486ArithmeticOperation(State, ModRegRm.Register, Value, Immediate, 16);
 465
 466         /* Unless this is CMP, write back the result */
 467         if (ModRegRm.Register != 7)
 468         {
 469             Fast486WriteModrmWordOperands(State, &ModRegRm, FALSE, Value);
 470         }
 471     }
 472 }
 473
 474 FAST486_OPCODE_HANDLER(Fast486OpcodeGroup8F)
 475 {
 476     ULONG Value;
 477     FAST486_MOD_REG_RM ModRegRm;
 478     BOOLEAN OperandSize, AddressSize;
 479
 480     OperandSize = AddressSize = State->SegmentRegs[FAST486_REG_CS].Size;
 481
 482     TOGGLE_OPSIZE(OperandSize);
 483     TOGGLE_ADSIZE(AddressSize);
 484
 485     /* Pop a value from the stack - this must be done first */
 486     if (!Fast486StackPop(State, &Value))
 487     {
 488         /* Exception occurred */
 489         return;
 490     }
 491
 492     if (!Fast486ParseModRegRm(State, AddressSize, &ModRegRm))
 493     {
 494         /* Exception occurred - restore SP */
 495         if (OperandSize) State->GeneralRegs[FAST486_REG_ESP].Long -= sizeof(ULONG);
 496         else State->GeneralRegs[FAST486_REG_ESP].LowWord -= sizeof(USHORT);
 497
 498         return;
 499     }
 500
 501     if (ModRegRm.Register != 0)
 502     {
 503         /* Invalid */
 504         Fast486Exception(State, FAST486_EXCEPTION_UD);
 505         return;
 506     }
 507
 508     if (OperandSize) Fast486WriteModrmDwordOperands(State, &ModRegRm, FALSE, Value);
 509     else Fast486WriteModrmWordOperands(State, &ModRegRm, FALSE, LOWORD(Value));
 510 }
 511
 512 FAST486_OPCODE_HANDLER(Fast486OpcodeGroupC0)
 513 {
 514     UCHAR Value, Count;
 515     FAST486_MOD_REG_RM ModRegRm;
 516     BOOLEAN AddressSize = State->SegmentRegs[FAST486_REG_CS].Size;
 517
 518     TOGGLE_ADSIZE(AddressSize);
 519
 520     if (!Fast486ParseModRegRm(State, AddressSize, &ModRegRm))
 521     {
 522         /* Exception occurred */
 523         return;
 524     }
 525
 526     /* Fetch the count */
 527     if (!Fast486FetchByte(State, &Count))
 528     {
 529         /* Exception occurred */
 530         return;
 531     }
 532
 533     /* Read the operands */
 534     if (!Fast486ReadModrmByteOperands(State, &ModRegRm, NULL, &Value))
 535     {
 536         /* Exception occurred */
 537         return;
 538     }
 539
 540     /* Calculate the result */
 541     Value = LOBYTE(Fast486RotateOperation(State,
 542                                           ModRegRm.Register,
 543                                           Value,
 544                                           8,
 545                                           Count));
 546
 547     /* Write back the result */
 548     Fast486WriteModrmByteOperands(State, &ModRegRm, FALSE, Value);
 549 }
 550
 551 FAST486_OPCODE_HANDLER(Fast486OpcodeGroupC1)
 552 {
 553     UCHAR Count;
 554     FAST486_MOD_REG_RM ModRegRm;
 555     BOOLEAN OperandSize, AddressSize;
 556
 557     OperandSize = AddressSize = State->SegmentRegs[FAST486_REG_CS].Size;
 558
 559     TOGGLE_OPSIZE(OperandSize);
 560     TOGGLE_ADSIZE(AddressSize);
 561
 562     if (!Fast486ParseModRegRm(State, AddressSize, &ModRegRm))
 563     {
 564         /* Exception occurred */
 565         return;
 566     }
 567
 568     /* Fetch the count */
 569     if (!Fast486FetchByte(State, &Count))
 570     {
 571         /* Exception occurred */
 572         return;
 573     }
 574
 575     if (OperandSize)
 576     {
 577         ULONG Value;
 578
 579         /* Read the operands */
 580         if (!Fast486ReadModrmDwordOperands(State, &ModRegRm, NULL, &Value))
 581         {
 582             /* Exception occurred */
 583             return;
 584         }
 585
 586         /* Calculate the result */
 587         Value = Fast486RotateOperation(State,
 588                                        ModRegRm.Register,
 589                                        Value,
 590                                        32,
 591                                        Count);
 592
 593         /* Write back the result */
 594         Fast486WriteModrmDwordOperands(State, &ModRegRm, FALSE, Value);
 595     }
 596     else
 597     {
 598         USHORT Value;
 599
 600         /* Read the operands */
 601         if (!Fast486ReadModrmWordOperands(State, &ModRegRm, NULL, &Value))
 602         {
 603             /* Exception occurred */
 604             return;
 605         }
 606
 607         /* Calculate the result */
 608         Value = LOWORD(Fast486RotateOperation(State,
 609                                               ModRegRm.Register,
 610                                               Value,
 611                                               16,
 612                                               Count));
 613
 614         /* Write back the result */
 615         Fast486WriteModrmWordOperands(State, &ModRegRm, FALSE, Value);
 616     }
 617 }
 618
 619 FAST486_OPCODE_HANDLER(Fast486OpcodeGroupC6)
 620 {
 621     UCHAR Immediate;
 622     FAST486_MOD_REG_RM ModRegRm;
 623     BOOLEAN AddressSize = State->SegmentRegs[FAST486_REG_CS].Size;
 624
 625     TOGGLE_ADSIZE(AddressSize);
 626
 627     if (!Fast486ParseModRegRm(State, AddressSize, &ModRegRm))
 628     {
 629         /* Exception occurred */
 630         return;
 631     }
 632
 633     if (ModRegRm.Register != 0)
 634     {
 635         /* Invalid */
 636         Fast486Exception(State, FAST486_EXCEPTION_UD);
 637         return;
 638     }
 639
 640     /* Get the immediate operand */
 641     if (!Fast486FetchByte(State, &Immediate))
 642     {
 643         /* Exception occurred */
 644         return;
 645     }
 646
 647     Fast486WriteModrmByteOperands(State, &ModRegRm, FALSE, Immediate);
 648 }
 649
 650 FAST486_OPCODE_HANDLER(Fast486OpcodeGroupC7)
 651 {
 652     FAST486_MOD_REG_RM ModRegRm;
 653     BOOLEAN OperandSize, AddressSize;
 654
 655     OperandSize = AddressSize = State->SegmentRegs[FAST486_REG_CS].Size;
 656
 657     TOGGLE_OPSIZE(OperandSize);
 658     TOGGLE_ADSIZE(AddressSize);
 659
 660     if (!Fast486ParseModRegRm(State, AddressSize, &ModRegRm))
 661     {
 662         /* Exception occurred */
 663         return;
 664     }
 665
 666     if (ModRegRm.Register != 0)
 667     {
 668         /* Invalid */
 669         Fast486Exception(State, FAST486_EXCEPTION_UD);
 670         return;
 671     }
 672
 673     if (OperandSize)
 674     {
 675         ULONG Immediate;
 676
 677         /* Get the immediate operand */
 678         if (!Fast486FetchDword(State, &Immediate))
 679         {
 680             /* Exception occurred */
 681             return;
 682         }
 683
 684         Fast486WriteModrmDwordOperands(State, &ModRegRm, FALSE, Immediate);
 685     }
 686     else
 687     {
 688         USHORT Immediate;
 689
 690         /* Get the immediate operand */
 691         if (!Fast486FetchWord(State, &Immediate))
 692         {
 693             /* Exception occurred */
 694             return;
 695         }
 696
 697         Fast486WriteModrmWordOperands(State, &ModRegRm, FALSE, Immediate);
 698     }
 699 }
 700
 701 FAST486_OPCODE_HANDLER(Fast486OpcodeGroupD0)
 702 {
 703     UCHAR Value;
 704     FAST486_MOD_REG_RM ModRegRm;
 705     BOOLEAN AddressSize = State->SegmentRegs[FAST486_REG_CS].Size;
 706
 707     TOGGLE_ADSIZE(AddressSize);
 708
 709     if (!Fast486ParseModRegRm(State, AddressSize, &ModRegRm))
 710     {
 711         /* Exception occurred */
 712         return;
 713     }
 714
 715     /* Read the operands */
 716     if (!Fast486ReadModrmByteOperands(State, &ModRegRm, NULL, &Value))
 717     {
 718         /* Exception occurred */
 719         return;
 720     }
 721
 722     /* Calculate the result */
 723     Value = LOBYTE(Fast486RotateOperation(State, ModRegRm.Register, Value, 8, 1));
 724
 725     /* Write back the result */
 726     Fast486WriteModrmByteOperands(State, &ModRegRm, FALSE, Value);
 727
 728 }
 729
 730 FAST486_OPCODE_HANDLER(Fast486OpcodeGroupD1)
 731 {
 732     FAST486_MOD_REG_RM ModRegRm;
 733     BOOLEAN OperandSize, AddressSize;
 734
 735     OperandSize = AddressSize = State->SegmentRegs[FAST486_REG_CS].Size;
 736
 737     TOGGLE_OPSIZE(OperandSize);
 738     TOGGLE_ADSIZE(AddressSize);
 739
 740     if (!Fast486ParseModRegRm(State, AddressSize, &ModRegRm))
 741     {
 742         /* Exception occurred */
 743         return;
 744     }
 745
 746     if (OperandSize)
 747     {
 748         ULONG Value;
 749
 750         /* Read the operands */
 751         if (!Fast486ReadModrmDwordOperands(State, &ModRegRm, NULL, &Value))
 752         {
 753             /* Exception occurred */
 754             return;
 755         }
 756
 757         /* Calculate the result */
 758         Value = Fast486RotateOperation(State, ModRegRm.Register, Value, 32, 1);
 759
 760         /* Write back the result */
 761         Fast486WriteModrmDwordOperands(State, &ModRegRm, FALSE, Value);
 762     }
 763     else
 764     {
 765         USHORT Value;
 766
 767         /* Read the operands */
 768         if (!Fast486ReadModrmWordOperands(State, &ModRegRm, NULL, &Value))
 769         {
 770             /* Exception occurred */
 771             return;
 772         }
 773
 774         /* Calculate the result */
 775         Value = LOWORD(Fast486RotateOperation(State, ModRegRm.Register, Value, 16, 1));
 776
 777         /* Write back the result */
 778         Fast486WriteModrmWordOperands(State, &ModRegRm, FALSE, Value);
 779     }
 780 }
 781
 782 FAST486_OPCODE_HANDLER(Fast486OpcodeGroupD2)
 783 {
 784     UCHAR Value;
 785     FAST486_MOD_REG_RM ModRegRm;
 786     BOOLEAN AddressSize = State->SegmentRegs[FAST486_REG_CS].Size;
 787
 788     TOGGLE_ADSIZE(AddressSize);
 789
 790     if (!Fast486ParseModRegRm(State, AddressSize, &ModRegRm))
 791     {
 792         /* Exception occurred */
 793         return;
 794     }
 795
 796     /* Read the operands */
 797     if (!Fast486ReadModrmByteOperands(State, &ModRegRm, NULL, &Value))
 798     {
 799         /* Exception occurred */
 800         return;
 801     }
 802
 803     /* Calculate the result */
 804     Value = LOBYTE(Fast486RotateOperation(State,
 805                                           ModRegRm.Register,
 806                                           Value,
 807                                           8,
 808                                           State->GeneralRegs[FAST486_REG_ECX].LowByte));
 809
 810     /* Write back the result */
 811     Fast486WriteModrmByteOperands(State, &ModRegRm, FALSE, Value);
 812 }
 813
 814 FAST486_OPCODE_HANDLER(Fast486OpcodeGroupD3)
 815 {
 816     FAST486_MOD_REG_RM ModRegRm;
 817     BOOLEAN OperandSize, AddressSize;
 818
 819     OperandSize = AddressSize = State->SegmentRegs[FAST486_REG_CS].Size;
 820
 821     TOGGLE_OPSIZE(OperandSize);
 822     TOGGLE_ADSIZE(AddressSize);
 823
 824     if (!Fast486ParseModRegRm(State, AddressSize, &ModRegRm))
 825     {
 826         /* Exception occurred */
 827         return;
 828     }
 829
 830     if (OperandSize)
 831     {
 832         ULONG Value;
 833
 834         /* Read the operands */
 835         if (!Fast486ReadModrmDwordOperands(State, &ModRegRm, NULL, &Value))
 836         {
 837             /* Exception occurred */
 838             return;
 839         }
 840
 841         /* Calculate the result */
 842         Value = Fast486RotateOperation(State,
 843                                        ModRegRm.Register,
 844                                        Value,
 845                                        32,
 846                                        State->GeneralRegs[FAST486_REG_ECX].LowByte);
 847
 848         /* Write back the result */
 849         Fast486WriteModrmDwordOperands(State, &ModRegRm, FALSE, Value);
 850     }
 851     else
 852     {
 853         USHORT Value;
 854
 855         /* Read the operands */
 856         if (!Fast486ReadModrmWordOperands(State, &ModRegRm, NULL, &Value))
 857         {
 858             /* Exception occurred */
 859             return;
 860         }
 861
 862         /* Calculate the result */
 863         Value = LOWORD(Fast486RotateOperation(State,
 864                                               ModRegRm.Register,
 865                                               Value,
 866                                               16,
 867                                               State->GeneralRegs[FAST486_REG_ECX].LowByte));
 868
 869         /* Write back the result */
 870         Fast486WriteModrmWordOperands(State, &ModRegRm, FALSE, Value);
 871     }
 872 }
 873
 874 FAST486_OPCODE_HANDLER(Fast486OpcodeGroupF6)
 875 {
 876     UCHAR Value = 0;
 877     FAST486_MOD_REG_RM ModRegRm;
 878     BOOLEAN AddressSize = State->SegmentRegs[FAST486_REG_CS].Size;
 879
 880     TOGGLE_ADSIZE(AddressSize);
 881
 882     if (!Fast486ParseModRegRm(State, AddressSize, &ModRegRm))
 883     {
 884         /* Exception occurred */
 885         return;
 886     }
 887
 888     /* Read the operands */
 889     if (!Fast486ReadModrmByteOperands(State, &ModRegRm, NULL, &Value))
 890     {
 891         /* Exception occurred */
 892         return;
 893     }
 894
 895     switch (ModRegRm.Register)
 896     {
 897         /* TEST */
 898         case 0:
 899         case 1:
 900         {
 901             UCHAR Immediate, Result;
 902
 903             /* Fetch the immediate byte */
 904             if (!Fast486FetchByte(State, &Immediate))
 905             {
 906                 /* Exception occurred */
 907                 return;
 908             }
 909
 910             /* Calculate the result */
 911             Result = Value & Immediate;
 912
 913             /* Update the flags */
 914             State->Flags.Cf = FALSE;
 915             State->Flags.Of = FALSE;
 916             State->Flags.Zf = (Result == 0);
 917             State->Flags.Sf = ((Result & SIGN_FLAG_BYTE) != 0);
 918             State->Flags.Pf = Fast486CalculateParity(Result);
 919
 920             break;
 921         }
 922
 923         /* NOT */
 924         case 2:
 925         {
 926             /* Write back the result */
 927             Fast486WriteModrmByteOperands(State, &ModRegRm, FALSE, ~Value);
 928
 929             break;
 930         }
 931
 932         /* NEG */
 933         case 3:
 934         {
 935             /* Calculate the result */
 936             UCHAR Result = -Value;
 937
 938             /* Update the flags */
 939             State->Flags.Cf = (Value != 0);
 940             State->Flags.Of = (Value & SIGN_FLAG_BYTE) && (Result & SIGN_FLAG_BYTE);
 941             State->Flags.Af = ((Value & 0x0F) != 0);
 942             State->Flags.Zf = (Result == 0);
 943             State->Flags.Sf = ((Result & SIGN_FLAG_BYTE) != 0);
 944             State->Flags.Pf = Fast486CalculateParity(Result);
 945
 946             /* Write back the result */
 947             Fast486WriteModrmByteOperands(State, &ModRegRm, FALSE, Result);
 948
 949             break;
 950         }
 951
 952         /* MUL */
 953         case 4:
 954         {
 955             USHORT Result = (USHORT)Value * (USHORT)State->GeneralRegs[FAST486_REG_EAX].LowByte;
 956
 957             /* Update the flags */
 958             State->Flags.Cf = State->Flags.Of = (HIBYTE(Result) != 0);
 959
 960             /* Write back the result */
 961             State->GeneralRegs[FAST486_REG_EAX].LowWord = Result;
 962
 963             break;
 964         }
 965
 966         /* IMUL */
 967         case 5:
 968         {
 969             SHORT Result = (SHORT)((CHAR)Value) * (SHORT)((CHAR)State->GeneralRegs[FAST486_REG_EAX].LowByte);
 970
 971             /* Update the flags */
 972             State->Flags.Cf = State->Flags.Of = ((Result < -128) || (Result > 127));
 973
 974             /* Write back the result */
 975             State->GeneralRegs[FAST486_REG_EAX].LowWord = (USHORT)Result;
 976
 977             break;
 978         }
 979
 980         /* DIV */
 981         case 6:
 982         {
 983             USHORT Quotient;
 984             UCHAR Remainder;
 985
 986             if (Value == 0)
 987             {
 988                 /* Divide error */
 989                 Fast486Exception(State, FAST486_EXCEPTION_DE);
 990                 return;
 991             }
 992
 993             Quotient = State->GeneralRegs[FAST486_REG_EAX].LowWord / Value;
 994             Remainder = State->GeneralRegs[FAST486_REG_EAX].LowWord % Value;
 995
 996             if (Quotient > 0xFF)
 997             {
 998                 /* Divide error */
 999                 Fast486Exception(State, FAST486_EXCEPTION_DE);
1000                 return;
1001             }
1002
1003             /* Write back the results */
1004             State->GeneralRegs[FAST486_REG_EAX].LowByte = (UCHAR)Quotient;
1005             State->GeneralRegs[FAST486_REG_EAX].HighByte = Remainder;
1006
1007             break;
1008         }
1009
1010         /* IDIV */
1011         case 7:
1012         {
1013             SHORT Quotient;
1014             CHAR Remainder;
1015
1016             if (Value == 0)
1017             {
1018                 /* Divide error */
1019                 Fast486Exception(State, FAST486_EXCEPTION_DE);
1020                 return;
1021             }
1022
1023             Quotient = (SHORT)State->GeneralRegs[FAST486_REG_EAX].LowWord / (CHAR)Value;
1024             Remainder = (SHORT)State->GeneralRegs[FAST486_REG_EAX].LowWord % (CHAR)Value;
1025
1026             if (Quotient > 127 || Quotient < -128)
1027             {
1028                 /* Divide error */
1029                 Fast486Exception(State, FAST486_EXCEPTION_DE);
1030                 return;
1031             }
1032
1033             /* Write back the results */
1034             State->GeneralRegs[FAST486_REG_EAX].LowByte = (UCHAR)((CHAR)Quotient);
1035             State->GeneralRegs[FAST486_REG_EAX].HighByte = (UCHAR)Remainder;
1036
1037             break;
1038         }
1039     }
1040 }
1041
1042 FAST486_OPCODE_HANDLER(Fast486OpcodeGroupF7)
1043 {
1044     ULONG Value = 0, SignFlag;
1045     FAST486_MOD_REG_RM ModRegRm;
1046     BOOLEAN OperandSize, AddressSize;
1047
1048     OperandSize = AddressSize = State->SegmentRegs[FAST486_REG_CS].Size;
1049
1050     TOGGLE_OPSIZE(OperandSize);
1051     TOGGLE_ADSIZE(AddressSize);
1052
1053     if (!Fast486ParseModRegRm(State, AddressSize, &ModRegRm))
1054     {
1055         /* Exception occurred */
1056         return;
1057     }
1058
1059     /* Set the sign flag */
1060     if (OperandSize) SignFlag = SIGN_FLAG_LONG;
1061     else SignFlag = SIGN_FLAG_WORD;
1062
1063     /* Read the operand */
1064     if (OperandSize)
1065     {
1066         /* 32-bit */
1067         if (!Fast486ReadModrmDwordOperands(State, &ModRegRm, NULL, &Value))
1068         {
1069             /* Exception occurred */
1070             return;
1071         }
1072     }
1073     else
1074     {
1075         /* 16-bit */
1076         if (!Fast486ReadModrmWordOperands(State, &ModRegRm, NULL, (PUSHORT)&Value))
1077         {
1078             /* Exception occurred */
1079             return;
1080         }
1081     }
1082
1083     switch (ModRegRm.Register)
1084     {
1085         /* TEST */
1086         case 0:
1087         case 1:
1088         {
1089             ULONG Immediate = 0, Result = 0;
1090
1091             if (OperandSize)
1092             {
1093                 /* Fetch the immediate dword */
1094                 if (!Fast486FetchDword(State, &Immediate))
1095                 {
1096                     /* Exception occurred */
1097                     return;
1098                 }
1099             }
1100             else
1101             {
1102                 /* Fetch the immediate word */
1103                 if (!Fast486FetchWord(State, (PUSHORT)&Immediate))
1104                 {
1105                     /* Exception occurred */
1106                     return;
1107                 }
1108             }
1109
1110             /* Calculate the result */
1111             Result = Value & Immediate;
1112
1113             /* Update the flags */
1114             State->Flags.Cf = FALSE;
1115             State->Flags.Of = FALSE;
1116             State->Flags.Zf = (Result == 0);
1117             State->Flags.Sf = ((Result & SignFlag) != 0);
1118             State->Flags.Pf = Fast486CalculateParity(Result);
1119
1120             break;
1121         }
1122
1123         /* NOT */
1124         case 2:
1125         {
1126             /* Write back the result */
1127             if (OperandSize)
1128             {
1129                 /* 32-bit */
1130                 Fast486WriteModrmDwordOperands(State, &ModRegRm, FALSE, ~Value);
1131             }
1132             else
1133             {
1134                 /* 16-bit */
1135                 Fast486WriteModrmWordOperands(State, &ModRegRm, FALSE, LOWORD(~Value));
1136             }
1137
1138             break;
1139         }
1140
1141         /* NEG */
1142         case 3:
1143         {
1144             /* Calculate the result */
1145             ULONG Result = -(LONG)Value;
1146             if (!OperandSize) Result &= 0xFFFF;
1147
1148             /* Update the flags */
1149             State->Flags.Cf = (Value != 0);
1150             State->Flags.Of = (Value & SignFlag) && (Result & SignFlag);
1151             State->Flags.Af = ((Value & 0x0F) != 0);
1152             State->Flags.Zf = (Result == 0);
1153             State->Flags.Sf = ((Result & SignFlag) != 0);
1154             State->Flags.Pf = Fast486CalculateParity(Result);
1155
1156             /* Write back the result */
1157             if (OperandSize)
1158             {
1159                 /* 32-bit */
1160                 Fast486WriteModrmDwordOperands(State, &ModRegRm, FALSE, Result);
1161             }
1162             else
1163             {
1164                 /* 16-bit */
1165                 Fast486WriteModrmWordOperands(State, &ModRegRm, FALSE, LOWORD(Result));
1166             }
1167
1168             break;
1169         }
1170
1171         /* MUL */
1172         case 4:
1173         {
1174             if (OperandSize)
1175             {
1176                 ULONGLONG Result = (ULONGLONG)Value * (ULONGLONG)State->GeneralRegs[FAST486_REG_EAX].Long;
1177
1178                 /* Update the flags */
1179                 State->Flags.Cf = State->Flags.Of = ((Result & 0xFFFFFFFF00000000ULL) != 0);
1180
1181                 /* Write back the result */
1182                 State->GeneralRegs[FAST486_REG_EAX].Long = Result & 0xFFFFFFFFULL;
1183                 State->GeneralRegs[FAST486_REG_EDX].Long = Result >> 32;
1184             }
1185             else
1186             {
1187                 ULONG Result = (ULONG)Value * (ULONG)State->GeneralRegs[FAST486_REG_EAX].LowWord;
1188
1189                 /* Update the flags */
1190                 State->Flags.Cf = State->Flags.Of = (HIWORD(Result) != 0);
1191
1192                 /* Write back the result */
1193                 State->GeneralRegs[FAST486_REG_EAX].LowWord = LOWORD(Result);
1194                 State->GeneralRegs[FAST486_REG_EDX].LowWord = HIWORD(Result);
1195             }
1196
1197             break;
1198         }
1199
1200         /* IMUL */
1201         case 5:
1202         {
1203             if (OperandSize)
1204             {
1205                 LONGLONG Result = (LONGLONG)((LONG)Value) * (LONGLONG)((LONG)State->GeneralRegs[FAST486_REG_EAX].Long);
1206
1207                 /* Update the flags */
1208                 State->Flags.Cf = State->Flags.Of = ((Result < -2147483648LL) || (Result > 2147483647LL));
1209
1210                 /* Write back the result */
1211                 State->GeneralRegs[FAST486_REG_EAX].Long = Result & 0xFFFFFFFFULL;
1212                 State->GeneralRegs[FAST486_REG_EDX].Long = Result >> 32;
1213             }
1214             else
1215             {
1216                 LONG Result = (LONG)((SHORT)Value) * (LONG)((SHORT)State->GeneralRegs[FAST486_REG_EAX].LowWord);
1217
1218                 /* Update the flags */
1219                 State->Flags.Cf = State->Flags.Of = ((Result < -32768) || (Result > 32767));
1220
1221                 /* Write back the result */
1222                 State->GeneralRegs[FAST486_REG_EAX].LowWord = LOWORD(Result);
1223                 State->GeneralRegs[FAST486_REG_EDX].LowWord = HIWORD(Result);
1224             }
1225
1226             break;
1227         }
1228
1229         /* DIV */
1230         case 6:
1231         {
1232             if (Value == 0)
1233             {
1234                 /* Divide error */
1235                 Fast486Exception(State, FAST486_EXCEPTION_DE);
1236                 return;
1237             }
1238
1239             if (OperandSize)
1240             {
1241                 ULONGLONG Dividend = (ULONGLONG)State->GeneralRegs[FAST486_REG_EAX].Long
1242                                      | ((ULONGLONG)State->GeneralRegs[FAST486_REG_EDX].Long << 32);
1243                 ULONGLONG Quotient = Dividend / Value;
1244                 ULONG Remainder = Dividend % Value;
1245
1246                 if (Quotient > 0xFFFFFFFFULL)
1247                 {
1248                     /* Divide error */
1249                     Fast486Exception(State, FAST486_EXCEPTION_DE);
1250                     return;
1251                 }
1252
1253                 /* Write back the results */
1254                 State->GeneralRegs[FAST486_REG_EAX].Long = (ULONG)Quotient;
1255                 State->GeneralRegs[FAST486_REG_EDX].Long = Remainder;
1256             }
1257             else
1258             {
1259                 ULONG Dividend = (ULONG)State->GeneralRegs[FAST486_REG_EAX].LowWord
1260                                  | ((ULONG)State->GeneralRegs[FAST486_REG_EDX].LowWord << 16);
1261                 ULONG Quotient = Dividend / Value;
1262                 USHORT Remainder = Dividend % Value;
1263
1264                 if (Quotient > 0xFFFF)
1265                 {
1266                     /* Divide error */
1267                     Fast486Exception(State, FAST486_EXCEPTION_DE);
1268                     return;
1269                 }
1270
1271                 /* Write back the results */
1272                 State->GeneralRegs[FAST486_REG_EAX].LowWord = (USHORT)Quotient;
1273                 State->GeneralRegs[FAST486_REG_EDX].LowWord = Remainder;
1274             }
1275
1276             break;
1277         }
1278
1279         /* IDIV */
1280         case 7:
1281         {
1282             if (Value == 0)
1283             {
1284                 /* Divide error */
1285                 Fast486Exception(State, FAST486_EXCEPTION_DE);
1286                 return;
1287             }
1288
1289             if (OperandSize)
1290             {
1291                 LONGLONG Dividend = (LONGLONG)State->GeneralRegs[FAST486_REG_EAX].Long
1292                                      | ((LONGLONG)State->GeneralRegs[FAST486_REG_EDX].Long << 32);
1293                 LONGLONG Quotient = Dividend / (LONG)Value;
1294                 LONG Remainder = Dividend % (LONG)Value;
1295
1296                 if (Quotient > 2147483647LL || Quotient < -2147483648LL)
1297                 {
1298                     /* Divide error */
1299                     Fast486Exception(State, FAST486_EXCEPTION_DE);
1300                     return;
1301                 }
1302
1303                 /* Write back the results */
1304                 State->GeneralRegs[FAST486_REG_EAX].Long = (ULONG)((LONG)Quotient);
1305                 State->GeneralRegs[FAST486_REG_EDX].Long = (ULONG)Remainder;
1306             }
1307             else
1308             {
1309                 LONG Dividend = (LONG)State->GeneralRegs[FAST486_REG_EAX].LowWord
1310                                  | ((LONG)State->GeneralRegs[FAST486_REG_EDX].LowWord << 16);
1311                 LONG Quotient = Dividend / (SHORT)LOWORD(Value);
1312                 SHORT Remainder = Dividend % (SHORT)LOWORD(Value);
1313
1314                 if (Quotient > 32767 || Quotient < -32768)
1315                 {
1316                     /* Divide error */
1317                     Fast486Exception(State, FAST486_EXCEPTION_DE);
1318                     return;
1319                 }
1320
1321                 /* Write back the results */
1322                 State->GeneralRegs[FAST486_REG_EAX].LowWord = (USHORT)((SHORT)Quotient);
1323                 State->GeneralRegs[FAST486_REG_EDX].LowWord = (USHORT)Remainder;
1324             }
1325
1326             break;
1327         }
1328     }
1329 }
1330
1331 FAST486_OPCODE_HANDLER(Fast486OpcodeGroupFE)
1332 {
1333     UCHAR Value;
1334     FAST486_MOD_REG_RM ModRegRm;
1335     BOOLEAN AddressSize = State->SegmentRegs[FAST486_REG_CS].Size;
1336
1337     TOGGLE_ADSIZE(AddressSize);
1338
1339     if (!Fast486ParseModRegRm(State, AddressSize, &ModRegRm))
1340     {
1341         /* Exception occurred */
1342         return;
1343     }
1344
1345     if (ModRegRm.Register > 1)
1346     {
1347         /* Invalid */
1348         Fast486Exception(State, FAST486_EXCEPTION_UD);
1349         return;
1350     }
1351
1352     /* Read the operands */
1353     if (!Fast486ReadModrmByteOperands(State, &ModRegRm, NULL, &Value))
1354     {
1355         /* Exception occurred */
1356         return;
1357     }
1358
1359     if (ModRegRm.Register == 0)
1360     {
1361         /* Increment and update OF and AF */
1362         Value++;
1363         State->Flags.Of = (Value == SIGN_FLAG_BYTE);
1364         State->Flags.Af = ((Value & 0x0F) == 0);
1365     }
1366     else
1367     {
1368         /* Decrement and update OF and AF */
1369         State->Flags.Of = (Value == SIGN_FLAG_BYTE);
1370         Value--;
1371         State->Flags.Af = ((Value & 0x0F) == 0x0F);
1372     }
1373
1374     /* Update flags */
1375     State->Flags.Zf = (Value == 0);
1376     State->Flags.Sf = ((Value & SIGN_FLAG_BYTE) != 0);
1377     State->Flags.Pf = Fast486CalculateParity(Value);
1378
1379     /* Write back the result */
1380     Fast486WriteModrmByteOperands(State, &ModRegRm, FALSE, Value);
1381 }
1382
1383 FAST486_OPCODE_HANDLER(Fast486OpcodeGroupFF)
1384 {
1385     FAST486_MOD_REG_RM ModRegRm;
1386     BOOLEAN OperandSize, AddressSize;
1387
1388     OperandSize = AddressSize = State->SegmentRegs[FAST486_REG_CS].Size;
1389
1390     TOGGLE_OPSIZE(OperandSize);
1391     TOGGLE_ADSIZE(AddressSize);
1392
1393     if (!Fast486ParseModRegRm(State, AddressSize, &ModRegRm))
1394     {
1395         /* Exception occurred */
1396         return;
1397     }
1398
1399     if (ModRegRm.Register == 7)
1400     {
1401         /* Invalid */
1402         Fast486Exception(State, FAST486_EXCEPTION_UD);
1403         return;
1404     }
1405
1406     /* Read the operands */
1407     if (OperandSize)
1408     {
1409         ULONG Value;
1410
1411         if (!Fast486ReadModrmDwordOperands(State, &ModRegRm, NULL, &Value))
1412         {
1413             /* Exception occurred */
1414             return;
1415         }
1416
1417         if (ModRegRm.Register == 0)
1418         {
1419             /* Increment and update OF and AF */
1420             Value++;
1421             State->Flags.Of = (Value == SIGN_FLAG_LONG);
1422             State->Flags.Af = ((Value & 0x0F) == 0);
1423         }
1424         else if (ModRegRm.Register == 1)
1425         {
1426             /* Decrement and update OF and AF */
1427             State->Flags.Of = (Value == SIGN_FLAG_LONG);
1428             Value--;
1429             State->Flags.Af = ((Value & 0x0F) == 0x0F);
1430         }
1431         else if (ModRegRm.Register == 2)
1432         {
1433             /* Push the current value of EIP */
1434             if (!Fast486StackPush(State, State->InstPtr.Long))
1435             {
1436                 /* Exception occurred */
1437                 return;
1438             }
1439
1440             /* Set the EIP to the address */
1441             State->InstPtr.Long = Value;
1442         }
1443         else if (ModRegRm.Register == 3)
1444         {
1445             USHORT Selector;
1446             FAST486_SEG_REGS Segment = FAST486_REG_DS;
1447
1448             /* Check for the segment override */
1449             if (State->PrefixFlags & FAST486_PREFIX_SEG)
1450             {
1451                 /* Use the override segment instead */
1452                 Segment = State->SegmentOverride;
1453             }
1454
1455             /* Read the selector */
1456             if (!Fast486ReadMemory(State,
1457                                    Segment,
1458                                    ModRegRm.MemoryAddress + sizeof(ULONG),
1459                                    FALSE,
1460                                    &Selector,
1461                                    sizeof(USHORT)))
1462             {
1463                 /* Exception occurred */
1464                 return;
1465             }
1466
1467             if (State->ControlRegisters[FAST486_REG_CR0] & FAST486_CR0_PE)
1468             {
1469                 if (!Fast486ProcessGate(State, Selector, Value, TRUE))
1470                 {
1471                     /* Gate processed or exception occurred */
1472                     return;
1473                 }
1474             }
1475
1476             /* Push the current value of CS */
1477             if (!Fast486StackPush(State, State->SegmentRegs[FAST486_REG_CS].Selector))
1478             {
1479                 /* Exception occurred */
1480                 return;
1481             }
1482
1483             /* Push the current value of EIP */
1484             if (!Fast486StackPush(State, State->InstPtr.Long))
1485             {
1486                 /* Exception occurred */
1487                 return;
1488             }
1489
1490             /* Load the new code segment */
1491             if (!Fast486LoadSegment(State, FAST486_REG_CS, Selector))
1492             {
1493                 /* Exception occurred */
1494                 return;
1495             }
1496
1497             /* Set the EIP to the address */
1498             State->InstPtr.Long = Value;
1499         }
1500         else if (ModRegRm.Register == 4)
1501         {
1502             /* Set the EIP to the address */
1503             State->InstPtr.Long = Value;
1504         }
1505         else if (ModRegRm.Register == 5)
1506         {
1507             USHORT Selector;
1508             FAST486_SEG_REGS Segment = FAST486_REG_DS;
1509
1510             /* Check for the segment override */
1511             if (State->PrefixFlags & FAST486_PREFIX_SEG)
1512             {
1513                 /* Use the override segment instead */
1514                 Segment = State->SegmentOverride;
1515             }
1516
1517             /* Read the selector */
1518             if (!Fast486ReadMemory(State,
1519                                    Segment,
1520                                    ModRegRm.MemoryAddress + sizeof(ULONG),
1521                                    FALSE,
1522                                    &Selector,
1523                                    sizeof(USHORT)))
1524             {
1525                 /* Exception occurred */
1526                 return;
1527             }
1528
1529             if (State->ControlRegisters[FAST486_REG_CR0] & FAST486_CR0_PE)
1530             {
1531                 if (!Fast486ProcessGate(State, Selector, Value, FALSE))
1532                 {
1533                     /* Gate processed or exception occurred */
1534                     return;
1535                 }
1536             }
1537
1538             /* Load the new code segment */
1539             if (!Fast486LoadSegment(State, FAST486_REG_CS, Selector))
1540             {
1541                 /* Exception occurred */
1542                 return;
1543             }
1544
1545             /* Set the EIP to the address */
1546             State->InstPtr.Long = Value;
1547         }
1548         else if (ModRegRm.Register == 6)
1549         {
1550             /* Push the value on to the stack */
1551             Fast486StackPush(State, Value);
1552             return;
1553         }
1554
1555         if (ModRegRm.Register <= 1)
1556         {
1557             /* Update flags */
1558             State->Flags.Sf = ((Value & SIGN_FLAG_LONG) != 0);
1559             State->Flags.Zf = (Value == 0);
1560             State->Flags.Pf = Fast486CalculateParity(Value);
1561
1562             /* Write back the result */
1563             Fast486WriteModrmDwordOperands(State, &ModRegRm, FALSE, Value);
1564         }
1565     }
1566     else
1567     {
1568         USHORT Value;
1569
1570         if (!Fast486ReadModrmWordOperands(State, &ModRegRm, NULL, &Value))
1571         {
1572             /* Exception occurred */
1573             return;
1574         }
1575
1576         if (ModRegRm.Register == 0)
1577         {
1578             /* Increment and update OF */
1579             Value++;
1580             State->Flags.Of = (Value == SIGN_FLAG_WORD);
1581             State->Flags.Af = ((Value & 0x0F) == 0);
1582         }
1583         else if (ModRegRm.Register == 1)
1584         {
1585             /* Decrement and update OF */
1586             State->Flags.Of = (Value == SIGN_FLAG_WORD);
1587             Value--;
1588             State->Flags.Af = ((Value & 0x0F) == 0x0F);
1589         }
1590         else if (ModRegRm.Register == 2)
1591         {
1592             /* Push the current value of IP */
1593             if (!Fast486StackPush(State, State->InstPtr.LowWord))
1594             {
1595                 /* Exception occurred */
1596                 return;
1597             }
1598
1599             /* Set the IP to the address */
1600             State->InstPtr.LowWord = Value;
1601
1602             /* Clear the top half of EIP */
1603             State->InstPtr.Long &= 0xFFFF;
1604         }
1605         else if (ModRegRm.Register == 3)
1606         {
1607             USHORT Selector;
1608             FAST486_SEG_REGS Segment = FAST486_REG_DS;
1609
1610             /* Check for the segment override */
1611             if (State->PrefixFlags & FAST486_PREFIX_SEG)
1612             {
1613                 /* Use the override segment instead */
1614                 Segment = State->SegmentOverride;
1615             }
1616
1617             /* Read the selector */
1618             if (!Fast486ReadMemory(State,
1619                                    Segment,
1620                                    ModRegRm.MemoryAddress + sizeof(USHORT),
1621                                    FALSE,
1622                                    &Selector,
1623                                    sizeof(USHORT)))
1624             {
1625                 /* Exception occurred */
1626                 return;
1627             }
1628
1629             /* Push the current value of CS */
1630             if (!Fast486StackPush(State, State->SegmentRegs[FAST486_REG_CS].Selector))
1631             {
1632                 /* Exception occurred */
1633                 return;
1634             }
1635
1636             /* Push the current value of IP */
1637             if (!Fast486StackPush(State, State->InstPtr.LowWord))
1638             {
1639                 /* Exception occurred */
1640                 return;
1641             }
1642
1643             /* Load the new code segment */
1644             if (!Fast486LoadSegment(State, FAST486_REG_CS, Selector))
1645             {
1646                 /* Exception occurred */
1647                 return;
1648             }
1649
1650             /* Set the IP to the address */
1651             State->InstPtr.LowWord = Value;
1652
1653             /* Clear the top half of EIP */
1654             State->InstPtr.Long &= 0xFFFF;
1655         }
1656         else if (ModRegRm.Register == 4)
1657         {
1658             /* Set the IP to the address */
1659             State->InstPtr.LowWord = Value;
1660
1661             /* Clear the top half of EIP */
1662             State->InstPtr.Long &= 0xFFFF;
1663         }
1664         else if (ModRegRm.Register == 5)
1665         {
1666             USHORT Selector;
1667             FAST486_SEG_REGS Segment = FAST486_REG_DS;
1668
1669             /* Check for the segment override */
1670             if (State->PrefixFlags & FAST486_PREFIX_SEG)
1671             {
1672                 /* Use the override segment instead */
1673                 Segment = State->SegmentOverride;
1674             }
1675
1676             /* Read the selector */
1677             if (!Fast486ReadMemory(State,
1678                                    Segment,
1679                                    ModRegRm.MemoryAddress + sizeof(USHORT),
1680                                    FALSE,
1681                                    &Selector,
1682                                    sizeof(USHORT)))
1683             {
1684                 /* Exception occurred */
1685                 return;
1686             }
1687
1688             /* Load the new code segment */
1689             if (!Fast486LoadSegment(State, FAST486_REG_CS, Selector))
1690             {
1691                 /* Exception occurred */
1692                 return;
1693             }
1694
1695             /* Set the IP to the address */
1696             State->InstPtr.LowWord = Value;
1697
1698             /* Clear the top half of EIP */
1699             State->InstPtr.Long &= 0xFFFF;
1700         }
1701         else if (ModRegRm.Register == 6)
1702         {
1703             /* Push the value on to the stack */
1704             Fast486StackPush(State, Value);
1705             return;
1706         }
1707         else
1708         {
1709             /* Invalid */
1710             Fast486Exception(State, FAST486_EXCEPTION_UD);
1711             return;
1712         }
1713
1714         if (ModRegRm.Register <= 1)
1715         {
1716             /* Update flags */
1717             State->Flags.Sf = ((Value & SIGN_FLAG_WORD) != 0);
1718             State->Flags.Zf = (Value == 0);
1719             State->Flags.Pf = Fast486CalculateParity(Value);
1720
1721             /* Write back the result */
1722             Fast486WriteModrmWordOperands(State, &ModRegRm, FALSE, Value);
1723         }
1724     }
1725 }
1726
1727 FAST486_OPCODE_HANDLER(Fast486ExtOpcodeGroup0F00)
1728 {
1729     FAST486_MOD_REG_RM ModRegRm;
1730     BOOLEAN AddressSize = State->SegmentRegs[FAST486_REG_CS].Size;
1731
1732     NO_LOCK_PREFIX();
1733     TOGGLE_ADSIZE(AddressSize);
1734
1735     if (!Fast486ParseModRegRm(State, AddressSize, &ModRegRm))
1736     {
1737         /* Exception occurred */
1738         return;
1739     }
1740
1741     /* Check which operation this is */
1742     switch (ModRegRm.Register)
1743     {
1744         /* SLDT */
1745         case 0:
1746         {
1747             /* Not recognized in real mode or virtual 8086 mode */
1748             if (!(State->ControlRegisters[FAST486_REG_CR0] & FAST486_CR0_PE)
1749                 || State->Flags.Vm)
1750             {
1751                 Fast486Exception(State, FAST486_EXCEPTION_UD);
1752                 return;
1753             }
1754
1755             Fast486WriteModrmWordOperands(State, &ModRegRm, FALSE, State->Ldtr.Selector);
1756             break;
1757         }
1758
1759         /* STR */
1760         case 1:
1761         {
1762             /* Not recognized in real mode or virtual 8086 mode */
1763             if (!(State->ControlRegisters[FAST486_REG_CR0] & FAST486_CR0_PE)
1764                 || State->Flags.Vm)
1765             {
1766                 Fast486Exception(State, FAST486_EXCEPTION_UD);
1767                 return;
1768             }
1769
1770             Fast486WriteModrmWordOperands(State, &ModRegRm, FALSE, State->TaskReg.Selector);
1771             break;
1772         }
1773
1774         /* LLDT */
1775         case 2:
1776         {
1777             BOOLEAN Valid;
1778             USHORT Selector;
1779             FAST486_SYSTEM_DESCRIPTOR GdtEntry;
1780
1781             /* Not recognized in real mode or virtual 8086 mode */
1782             if (!(State->ControlRegisters[FAST486_REG_CR0] & FAST486_CR0_PE)
1783                 || State->Flags.Vm)
1784             {
1785                 Fast486Exception(State, FAST486_EXCEPTION_UD);
1786                 return;
1787             }
1788
1789             /* This is a privileged instruction */
1790             if (Fast486GetCurrentPrivLevel(State) != 0)
1791             {
1792                 Fast486Exception(State, FAST486_EXCEPTION_GP);
1793                 return;
1794             }
1795
1796             if (!Fast486ReadModrmWordOperands(State,
1797                                               &ModRegRm,
1798                                               NULL,
1799                                               &Selector))
1800             {
1801                 /* Exception occurred */
1802                 return;
1803             }
1804
1805             if (Selector & SEGMENT_TABLE_INDICATOR)
1806             {
1807                 /* This selector doesn't point to the GDT */
1808                 Fast486ExceptionWithErrorCode(State, FAST486_EXCEPTION_GP, Selector);
1809                 return;
1810             }
1811
1812             if (!Fast486ReadDescriptorEntry(State,
1813                                             Selector,
1814                                             &Valid,
1815                                             (PFAST486_GDT_ENTRY)&GdtEntry))
1816             {
1817                 /* Exception occurred */
1818                 return;
1819             }
1820
1821             if (!Valid)
1822             {
1823                 /* Invalid selector */
1824                 Fast486ExceptionWithErrorCode(State, FAST486_EXCEPTION_GP, Selector);
1825                 return;
1826             }
1827
1828             if (GET_SEGMENT_INDEX(Selector) == 0)
1829             {
1830                 RtlZeroMemory(&State->Ldtr, sizeof(State->Ldtr));
1831                 return;
1832             }
1833
1834             if (!GdtEntry.Present)
1835             {
1836                 Fast486ExceptionWithErrorCode(State, FAST486_EXCEPTION_NP, Selector);
1837                 return;
1838             }
1839
1840             if (GdtEntry.Signature != FAST486_LDT_SIGNATURE)
1841             {
1842                 /* This is not a LDT descriptor */
1843                 Fast486ExceptionWithErrorCode(State, FAST486_EXCEPTION_GP, Selector);
1844                 return;
1845             }
1846
1847             /* Update the LDTR */
1848             State->Ldtr.Selector = Selector;
1849             State->Ldtr.Base = GdtEntry.Base | (GdtEntry.BaseMid << 16) | (GdtEntry.BaseHigh << 24);
1850             State->Ldtr.Limit = GdtEntry.Limit | (GdtEntry.LimitHigh << 16);
1851
1852             if (GdtEntry.Granularity)
1853             {
1854                 State->Ldtr.Limit <<= 12;
1855                 State->Ldtr.Limit |= 0x00000FFF;
1856             }
1857
1858             break;
1859         }
1860
1861         /* LTR */
1862         case 3:
1863         {
1864             BOOLEAN Valid;
1865             USHORT Selector;
1866             FAST486_SYSTEM_DESCRIPTOR GdtEntry;
1867
1868             /* Not recognized in real mode or virtual 8086 mode */
1869             if (!(State->ControlRegisters[FAST486_REG_CR0] & FAST486_CR0_PE)
1870                 || State->Flags.Vm)
1871             {
1872                 Fast486Exception(State, FAST486_EXCEPTION_UD);
1873                 return;
1874             }
1875
1876             /* This is a privileged instruction */
1877             if (Fast486GetCurrentPrivLevel(State) != 0)
1878             {
1879                 Fast486Exception(State, FAST486_EXCEPTION_GP);
1880                 return;
1881             }
1882
1883             if (!Fast486ReadModrmWordOperands(State,
1884                                               &ModRegRm,
1885                                               NULL,
1886                                               &Selector))
1887             {
1888                 /* Exception occurred */
1889                 return;
1890             }
1891
1892             if (Selector & SEGMENT_TABLE_INDICATOR)
1893             {
1894                 /* This selector doesn't point to the GDT */
1895                 Fast486ExceptionWithErrorCode(State, FAST486_EXCEPTION_GP, Selector);
1896                 return;
1897             }
1898
1899             if (!Fast486ReadDescriptorEntry(State,
1900                                             Selector,
1901                                             &Valid,
1902                                             (PFAST486_GDT_ENTRY)&GdtEntry))
1903             {
1904                 /* Exception occurred */
1905                 return;
1906             }
1907
1908             if (!Valid)
1909             {
1910                 /* Invalid selector */
1911                 Fast486ExceptionWithErrorCode(State, FAST486_EXCEPTION_GP, Selector);
1912                 return;
1913             }
1914
1915             if (GET_SEGMENT_INDEX(Selector) == 0)
1916             {
1917                 Fast486Exception(State, FAST486_EXCEPTION_GP);
1918                 return;
1919             }
1920
1921             if (!GdtEntry.Present)
1922             {
1923                 Fast486ExceptionWithErrorCode(State, FAST486_EXCEPTION_NP, Selector);
1924                 return;
1925             }
1926
1927             if (GdtEntry.Signature != FAST486_TSS_SIGNATURE)
1928             {
1929                 /* This is not a TSS descriptor */
1930                 Fast486ExceptionWithErrorCode(State, FAST486_EXCEPTION_GP, Selector);
1931                 return;
1932             }
1933
1934             /* Update the TR */
1935             State->TaskReg.Selector = Selector;
1936             State->TaskReg.Base = GdtEntry.Base | (GdtEntry.BaseMid << 16) | (GdtEntry.BaseHigh << 24);
1937             State->TaskReg.Limit = GdtEntry.Limit | (GdtEntry.LimitHigh << 16);
1938
1939             if (GdtEntry.Granularity)
1940             {
1941                 State->TaskReg.Limit <<= 12;
1942                 State->TaskReg.Limit |= 0x00000FFF;
1943             }
1944
1945             break;
1946         }
1947
1948         /* VERR/VERW */
1949         case 4:
1950         case 5:
1951         {
1952             USHORT Selector;
1953             BOOLEAN Valid;
1954             FAST486_GDT_ENTRY GdtEntry;
1955
1956             /* Not recognized in real mode or virtual 8086 mode */
1957             if (!(State->ControlRegisters[FAST486_REG_CR0] & FAST486_CR0_PE)
1958                 || State->Flags.Vm)
1959             {
1960                 Fast486Exception(State, FAST486_EXCEPTION_UD);
1961                 return;
1962             }
1963
1964             /* This is a privileged instruction */
1965             if (Fast486GetCurrentPrivLevel(State) != 0)
1966             {
1967                 Fast486Exception(State, FAST486_EXCEPTION_GP);
1968                 return;
1969             }
1970
1971             if (!Fast486ReadModrmWordOperands(State,
1972                                               &ModRegRm,
1973                                               NULL,
1974                                               &Selector))
1975             {
1976                 /* Exception occurred */
1977                 return;
1978             }
1979
1980             if (!Fast486ReadDescriptorEntry(State, Selector, &Valid, &GdtEntry))
1981             {
1982                 /* Exception occurred */
1983                 return;
1984             }
1985
1986             if (!Valid)
1987             {
1988                 /* Clear ZF */
1989                 State->Flags.Zf = FALSE;
1990                 return;
1991             }
1992
1993             /* Set ZF if it is valid and accessible */
1994             State->Flags.Zf = GdtEntry.Present // must be present
1995                                && GdtEntry.SystemType // must be a segment
1996                                && (((ModRegRm.Register == 4)
1997                                /* code segments are only readable if the RW bit is set */
1998                                && (!GdtEntry.Executable || GdtEntry.ReadWrite))
1999                                || ((ModRegRm.Register == 5)
2000                                /* code segments are never writable, data segments are writable when RW is set */
2001                                && (!GdtEntry.Executable && GdtEntry.ReadWrite)))
2002                                /*
2003                                 * for segments other than conforming code segments,
2004                                 * both RPL and CPL must be less than or equal to DPL
2005                                 */
2006                                && ((!GdtEntry.Executable || !GdtEntry.DirConf)
2007                                && ((GET_SEGMENT_RPL(Selector) <= GdtEntry.Dpl)
2008                                && (Fast486GetCurrentPrivLevel(State) <= GdtEntry.Dpl)))
2009                                /* for conforming code segments, DPL must be less than or equal to CPL */
2010                                && ((GdtEntry.Executable && GdtEntry.DirConf)
2011                                && (GdtEntry.Dpl <= Fast486GetCurrentPrivLevel(State)));
2012
2013
2014             break;
2015         }
2016
2017         /* Invalid */
2018         default:
2019         {
2020             Fast486Exception(State, FAST486_EXCEPTION_UD);
2021         }
2022     }
2023 }
2024
2025 FAST486_OPCODE_HANDLER(Fast486ExtOpcodeGroup0F01)
2026 {
2027     // FAST486_TABLE_REG TableReg;
2028     UCHAR TableReg[6];
2029     FAST486_MOD_REG_RM ModRegRm;
2030     BOOLEAN OperandSize, AddressSize;
2031     FAST486_SEG_REGS Segment = FAST486_REG_DS;
2032
2033     OperandSize = AddressSize = State->SegmentRegs[FAST486_REG_CS].Size;
2034
2035     NO_LOCK_PREFIX();
2036     TOGGLE_OPSIZE(OperandSize);
2037     TOGGLE_ADSIZE(AddressSize);
2038
2039     if (!Fast486ParseModRegRm(State, AddressSize, &ModRegRm))
2040     {
2041         /* Exception occurred */
2042         return;
2043     }
2044
2045     /* Check for the segment override */
2046     if (State->PrefixFlags & FAST486_PREFIX_SEG)
2047     {
2048         /* Use the override segment instead */
2049         Segment = State->SegmentOverride;
2050     }
2051
2052     /* Check which operation this is */
2053     switch (ModRegRm.Register)
2054     {
2055         /* SGDT */
2056         case 0:
2057         {
2058             if (!ModRegRm.Memory)
2059             {
2060                 /* The second operand must be a memory location */
2061                 Fast486Exception(State, FAST486_EXCEPTION_UD);
2062                 return;
2063             }
2064
2065             /* Fill the 6-byte table register */
2066             // TableReg = State->Gdtr;
2067             *((PUSHORT)&TableReg) = State->Gdtr.Size;
2068             *((PULONG)&TableReg[sizeof(USHORT)]) = State->Gdtr.Address;
2069
2070             /* Store the GDTR */
2071             Fast486WriteMemory(State,
2072                                Segment,
2073                                ModRegRm.MemoryAddress,
2074                                TableReg,
2075                                sizeof(TableReg));
2076
2077             break;
2078         }
2079
2080         /* SIDT */
2081         case 1:
2082         {
2083             if (!ModRegRm.Memory)
2084             {
2085                 /* The second operand must be a memory location */
2086                 Fast486Exception(State, FAST486_EXCEPTION_UD);
2087                 return;
2088             }
2089
2090             /* Fill the 6-byte table register */
2091             // TableReg = State->Idtr;
2092             *((PUSHORT)&TableReg) = State->Idtr.Size;
2093             *((PULONG)&TableReg[sizeof(USHORT)]) = State->Idtr.Address;
2094
2095             /* Store the IDTR */
2096             Fast486WriteMemory(State,
2097                                Segment,
2098                                ModRegRm.MemoryAddress,
2099                                TableReg,
2100                                sizeof(TableReg));
2101
2102             break;
2103         }
2104
2105         /* LGDT */
2106         case 2:
2107         {
2108             /* This is a privileged instruction */
2109             if (Fast486GetCurrentPrivLevel(State) != 0)
2110             {
2111                 Fast486Exception(State, FAST486_EXCEPTION_GP);
2112                 return;
2113             }
2114
2115             if (!ModRegRm.Memory)
2116             {
2117                 /* The second operand must be a memory location */
2118                 Fast486Exception(State, FAST486_EXCEPTION_UD);
2119                 return;
2120             }
2121
2122             /* Read the new GDTR */
2123             if (!Fast486ReadMemory(State,
2124                                    Segment,
2125                                    ModRegRm.MemoryAddress,
2126                                    FALSE,
2127                                    TableReg,
2128                                    sizeof(TableReg)))
2129             {
2130                 /* Exception occurred */
2131                 return;
2132             }
2133
2134             /* Load the new GDT */
2135             // State->Gdtr = TableReg;
2136             State->Gdtr.Size = *((PUSHORT)&TableReg);
2137             State->Gdtr.Address = *((PULONG)&TableReg[sizeof(USHORT)]);
2138
2139             /* In 16-bit mode the highest byte is masked out */
2140             if (!OperandSize) State->Gdtr.Address &= 0x00FFFFFF;
2141
2142             break;
2143         }
2144
2145         /* LIDT */
2146         case 3:
2147         {
2148             /* This is a privileged instruction */
2149             if (Fast486GetCurrentPrivLevel(State) != 0)
2150             {
2151                 Fast486Exception(State, FAST486_EXCEPTION_GP);
2152                 return;
2153             }
2154
2155             if (!ModRegRm.Memory)
2156             {
2157                 /* The second operand must be a memory location */
2158                 Fast486Exception(State, FAST486_EXCEPTION_UD);
2159                 return;
2160             }
2161
2162             /* Read the new IDTR */
2163             if (!Fast486ReadMemory(State,
2164                                    Segment,
2165                                    ModRegRm.MemoryAddress,
2166                                    FALSE,
2167                                    TableReg,
2168                                    sizeof(TableReg)))
2169             {
2170                 /* Exception occurred */
2171                 return;
2172             }
2173
2174             /* Load the new IDT */
2175             // State->Idtr = TableReg;
2176             State->Idtr.Size = *((PUSHORT)&TableReg);
2177             State->Idtr.Address = *((PULONG)&TableReg[sizeof(USHORT)]);
2178
2179             /* In 16-bit mode the highest byte is masked out */
2180             if (!OperandSize) State->Idtr.Address &= 0x00FFFFFF;
2181
2182             break;
2183         }
2184
2185         /* SMSW */
2186         case 4:
2187         {
2188             /* Store the lower 16 bits (Machine Status Word) of CR0 */
2189             Fast486WriteModrmWordOperands(State,
2190                                           &ModRegRm,
2191                                           FALSE,
2192                                           LOWORD(State->ControlRegisters[FAST486_REG_CR0]));
2193
2194             break;
2195         }
2196
2197         /* LMSW */
2198         case 6:
2199         {
2200             USHORT MachineStatusWord;
2201
2202             /* This is a privileged instruction */
2203             if (Fast486GetCurrentPrivLevel(State) != 0)
2204             {
2205                 Fast486Exception(State, FAST486_EXCEPTION_GP);
2206                 return;
2207             }
2208
2209             /* Read the new Machine Status Word */
2210             if (!Fast486ReadModrmWordOperands(State, &ModRegRm, NULL, &MachineStatusWord))
2211             {
2212                 /* Exception occurred */
2213                 return;
2214             }
2215
2216             /* This instruction cannot be used to return to real mode */
2217             if ((State->ControlRegisters[FAST486_REG_CR0] & FAST486_CR0_PE)
2218                 && !(MachineStatusWord & FAST486_CR0_PE))
2219             {
2220                 Fast486Exception(State, FAST486_EXCEPTION_GP);
2221                 return;
2222             }
2223
2224             /* Set the lowest 4 bits */
2225             State->ControlRegisters[FAST486_REG_CR0] &= 0xFFFFFFF0;
2226             State->ControlRegisters[FAST486_REG_CR0] |= MachineStatusWord & 0x0F;
2227
2228             break;
2229         }
2230
2231         /* INVLPG */
2232         case 7:
2233         {
2234 #ifndef FAST486_NO_PREFETCH
2235             /* Invalidate the prefetch */
2236             State->PrefetchValid = FALSE;
2237 #endif
2238
2239             /* This is a privileged instruction */
2240             if (Fast486GetCurrentPrivLevel(State) != 0)
2241             {
2242                 Fast486Exception(State, FAST486_EXCEPTION_GP);
2243                 return;
2244             }
2245
2246             if (!ModRegRm.Memory)
2247             {
2248                 /* The second operand must be a memory location */
2249                 Fast486Exception(State, FAST486_EXCEPTION_UD);
2250                 return;
2251             }
2252
2253             if (State->Tlb != NULL)
2254             {
2255                 /* Clear the TLB entry */
2256                 State->Tlb[ModRegRm.MemoryAddress >> 12] = INVALID_TLB_FIELD;
2257             }
2258
2259             break;
2260         }
2261
2262         /* Invalid */
2263         default:
2264         {
2265             Fast486Exception(State, FAST486_EXCEPTION_UD);
2266         }
2267     }
2268 }
2269
2270 FAST486_OPCODE_HANDLER(Fast486ExtOpcodeGroup0FB9)
2271 {
2272     FAST486_MOD_REG_RM ModRegRm;
2273     BOOLEAN AddressSize = State->SegmentRegs[FAST486_REG_CS].Size;
2274
2275     TOGGLE_ADSIZE(AddressSize);
2276
2277     if (!Fast486ParseModRegRm(State, AddressSize, &ModRegRm))
2278     {
2279         /* Exception occurred */
2280         return;
2281     }
2282
2283     /* All of them are reserved (UD2) */
2284     Fast486Exception(State, FAST486_EXCEPTION_UD);
2285     return;
2286 }
2287
2288 FAST486_OPCODE_HANDLER(Fast486ExtOpcodeGroup0FBA)
2289 {
2290     FAST486_MOD_REG_RM ModRegRm;
2291     BOOLEAN OperandSize, AddressSize;
2292     UINT DataSize;
2293     UCHAR BitNumber;
2294
2295     OperandSize = AddressSize = State->SegmentRegs[FAST486_REG_CS].Size;
2296
2297     TOGGLE_OPSIZE(OperandSize);
2298     TOGGLE_ADSIZE(AddressSize);
2299
2300     /* Get the number of bits */
2301     if (OperandSize) DataSize = 32;
2302     else DataSize = 16;
2303
2304     if (!Fast486ParseModRegRm(State, AddressSize, &ModRegRm))
2305     {
2306         /* Exception occurred */
2307         return;
2308     }
2309
2310     if (ModRegRm.Register < 4)
2311     {
2312         /* Invalid */
2313         Fast486Exception(State, FAST486_EXCEPTION_UD);
2314         return;
2315     }
2316
2317     /* Get the bit number */
2318     if (!Fast486FetchByte(State, &BitNumber))
2319     {
2320         /* Exception occurred */
2321         return;
2322     }
2323
2324     if (ModRegRm.Memory)
2325     {
2326         /*
2327          * For memory operands, add the bit offset divided by
2328          * the data size to the address
2329          */
2330         ModRegRm.MemoryAddress += BitNumber / DataSize;
2331     }
2332
2333     /* Normalize the bit number */
2334     BitNumber %= DataSize;
2335
2336     if (OperandSize)
2337     {
2338         ULONG Value;
2339
2340         /* Read the value */
2341         if (!Fast486ReadModrmDwordOperands(State, &ModRegRm, NULL, &Value))
2342         {
2343             /* Exception occurred */
2344             return;
2345         }
2346
2347         /* Set CF to the bit value */
2348         State->Flags.Cf = (Value >> BitNumber) & 1;
2349
2350         if (ModRegRm.Register == 5)
2351         {
2352             /* BTS */
2353             Value |= 1 << BitNumber;
2354         }
2355         else if (ModRegRm.Register == 6)
2356         {
2357             /* BTR */
2358             Value &= ~(1 << BitNumber);
2359         }
2360         else if (ModRegRm.Register == 7)
2361         {
2362             /* BTC */
2363             Value ^= 1 << BitNumber;
2364         }
2365
2366         if (ModRegRm.Register >= 5)
2367         {
2368             /* Write back the result */
2369             if (!Fast486WriteModrmDwordOperands(State, &ModRegRm, FALSE, Value))
2370             {
2371                 /* Exception occurred */
2372                 return;
2373             }
2374         }
2375     }
2376     else
2377     {
2378         USHORT Value;
2379
2380         /* Read the value */
2381         if (!Fast486ReadModrmWordOperands(State, &ModRegRm, NULL, &Value))
2382         {
2383             /* Exception occurred */
2384             return;
2385         }
2386
2387         /* Set CF to the bit value */
2388         State->Flags.Cf = (Value >> BitNumber) & 1;
2389
2390         if (ModRegRm.Register == 5)
2391         {
2392             /* BTS */
2393             Value |= 1 << BitNumber;
2394         }
2395         else if (ModRegRm.Register == 6)
2396         {
2397             /* BTR */
2398             Value &= ~(1 << BitNumber);
2399         }
2400         else if (ModRegRm.Register == 7)
2401         {
2402             /* BTC */
2403             Value ^= 1 << BitNumber;
2404         }
2405
2406         if (ModRegRm.Register >= 5)
2407         {
2408             /* Write back the result */
2409             if (!Fast486WriteModrmWordOperands(State, &ModRegRm, FALSE, Value))
2410             {
2411                 /* Exception occurred */
2412                 return;
2413             }
2414         }
2415     }
2416 }
2417
2418 /* EOF */