memory/instr.c

   1 /*
   2  * Emulation of priviledged instructions
   3  *
   4  * Copyright 1995 Alexandre Julliard
   5  */
   6
   7 #include "windef.h"
   8 #include "wingdi.h"
   9 #include "wine/winuser16.h"
  10 #include "ldt.h"
  11 #include "global.h"
  12 #include "module.h"
  13 #include "dosexe.h"
  14 #include "miscemu.h"
  15 #include "selectors.h"
  16 #include "debugtools.h"
  17
  18 DEFAULT_DEBUG_CHANNEL(int);
  19 DECLARE_DEBUG_CHANNEL(io);
  20
  21 #ifdef __i386__
  22
  23 #define IS_SEL_32(context,seg) \
  24    (ISV86(context) ? FALSE : IS_SELECTOR_32BIT(seg))
  25
  26 #define STACK_reg(context) \
  27    (IS_SEL_32(context,SS_reg(context)) ? ESP_reg(context) : (DWORD)LOWORD(ESP_reg(context)))
  28
  29 #define ADD_STACK_reg(context,offset) \
  30    do { if (IS_SEL_32(context,SS_reg(context))) ESP_reg(context) += (offset); \
  31         else ADD_LOWORD(ESP_reg(context),(offset)); } while(0)
  32
  33 #define MAKE_PTR(seg,off) \
  34    (IS_SELECTOR_SYSTEM(seg) ? (void *)(off) : PTR_SEG_OFF_TO_LIN(seg,off))
  35
  36 #define MK_PTR(context,seg,off) \
  37    (ISV86(context) ? DOSMEM_MapRealToLinear(MAKELONG(off,seg)) \
  38                    : MAKE_PTR(seg,off))
  39
  40 #define STACK_PTR(context) \
  41    (ISV86(context) ? \
  42     DOSMEM_MapRealToLinear(MAKELONG(LOWORD(ESP_reg(context)),SS_reg(context))) : \
  43     (IS_SELECTOR_SYSTEM(SS_reg(context)) ? (void *)ESP_reg(context) : \
  44      (PTR_SEG_OFF_TO_LIN(SS_reg(context),STACK_reg(context)))))
  45
  46 /***********************************************************************
  47  *           INSTR_ReplaceSelector
  48  *
  49  * Try to replace an invalid selector by a valid one.
  50  * The only selector where it is allowed to do "mov ax,40;mov es,ax"
  51  * is the so called 'bimodal' selector 0x40, which points to the BIOS
  52  * data segment. Used by (at least) Borland products (and programs compiled
  53  * using Borland products).
  54  *
  55  * See Undocumented Windows, Chapter 5, __0040.
  56  */
  57 static BOOL INSTR_ReplaceSelector( CONTEXT86 *context, WORD *sel )
  58 {
  59     extern char Call16_Start, Call16_End;
  60
  61     if (IS_SELECTOR_SYSTEM(CS_reg(context)))
  62         if (    (char *)EIP_reg(context) >= &Call16_Start
  63              && (char *)EIP_reg(context) <  &Call16_End   )
  64         {
  65             /* Saved selector may have become invalid when the relay code */
  66             /* tries to restore it. We simply clear it. */
  67             *sel = 0;
  68             return TRUE;
  69         }
  70
  71     if (*sel == 0x40)
  72     {
  73         static WORD sys_timer = 0;
  74         if (!sys_timer)
  75             sys_timer = CreateSystemTimer( 55, DOSMEM_Tick );
  76         *sel = DOSMEM_BiosDataSeg;
  77         return TRUE;
  78     }
  79     if (!IS_SELECTOR_SYSTEM(*sel) && !IS_SELECTOR_FREE(*sel))
  80         ERR("Got protection fault on valid selector, maybe your kernel is too old?\n" );
  81     return FALSE;  /* Can't replace selector, crashdump */
  82 }
  83
  84
  85 /***********************************************************************
  86  *           INSTR_GetOperandAddr
  87  *
  88  * Return the address of an instruction operand (from the mod/rm byte).
  89  */
  90 static BYTE *INSTR_GetOperandAddr( CONTEXT86 *context, BYTE *instr,
  91                                    int long_addr, int segprefix, int *len )
  92 {
  93     int mod, rm, base, index = 0, ss = 0, seg = 0, off;
  94
  95 #define GET_VAL(val,type) \
  96     { *val = *(type *)instr; instr += sizeof(type); *len += sizeof(type); }
  97
  98     *len = 0;
  99     GET_VAL( &mod, BYTE );
 100     rm = mod & 7;
 101     mod >>= 6;
 102
 103     if (mod == 3)
 104     {
 105         switch(rm)
 106         {
 107         case 0: return (BYTE *)&EAX_reg(context);
 108         case 1: return (BYTE *)&ECX_reg(context);
 109         case 2: return (BYTE *)&EDX_reg(context);
 110         case 3: return (BYTE *)&EBX_reg(context);
 111         case 4: return (BYTE *)&ESP_reg(context);
 112         case 5: return (BYTE *)&EBP_reg(context);
 113         case 6: return (BYTE *)&ESI_reg(context);
 114         case 7: return (BYTE *)&EDI_reg(context);
 115         }
 116     }
 117
 118     if (long_addr)
 119     {
 120         if (rm == 4)
 121         {
 122             BYTE sib;
 123             GET_VAL( &sib, BYTE );
 124             rm = sib & 7;
 125             ss = sib >> 6;
 126             switch(sib >> 3)
 127             {
 128             case 0: index = EAX_reg(context); break;
 129             case 1: index = ECX_reg(context); break;
 130             case 2: index = EDX_reg(context); break;
 131             case 3: index = EBX_reg(context); break;
 132             case 4: index = 0; break;
 133             case 5: index = EBP_reg(context); break;
 134             case 6: index = ESI_reg(context); break;
 135             case 7: index = EDI_reg(context); break;
 136             }
 137         }
 138
 139         switch(rm)
 140         {
 141         case 0: base = EAX_reg(context); seg = DS_reg(context); break;
 142         case 1: base = ECX_reg(context); seg = DS_reg(context); break;
 143         case 2: base = EDX_reg(context); seg = DS_reg(context); break;
 144         case 3: base = EBX_reg(context); seg = DS_reg(context); break;
 145         case 4: base = ESP_reg(context); seg = SS_reg(context); break;
 146         case 5: base = EBP_reg(context); seg = SS_reg(context); break;
 147         case 6: base = ESI_reg(context); seg = DS_reg(context); break;
 148         case 7: base = EDI_reg(context); seg = DS_reg(context); break;
 149         }
 150         switch (mod)
 151         {
 152         case 0:
 153             if (rm == 5)  /* special case: ds:(disp32) */
 154             {
 155                 GET_VAL( &base, DWORD );
 156                 seg = DS_reg(context);
 157             }
 158             break;
 159
 160         case 1:  /* 8-bit disp */
 161             GET_VAL( &off, BYTE );
 162             base += (signed char)off;
 163             break;
 164
 165         case 2:  /* 32-bit disp */
 166             GET_VAL( &off, DWORD );
 167             base += (signed long)off;
 168             break;
 169         }
 170     }
 171     else  /* short address */
 172     {
 173         switch(rm)
 174         {
 175         case 0:  /* ds:(bx,si) */
 176             base = LOWORD(EBX_reg(context)) + LOWORD(ESI_reg(context));
 177             seg  = DS_reg(context);
 178             break;
 179         case 1:  /* ds:(bx,di) */
 180             base = LOWORD(EBX_reg(context)) + LOWORD(EDI_reg(context));
 181             seg  = DS_reg(context);
 182             break;
 183         case 2:  /* ss:(bp,si) */
 184             base = LOWORD(EBP_reg(context)) + LOWORD(ESI_reg(context));
 185             seg  = SS_reg(context);
 186             break;
 187         case 3:  /* ss:(bp,di) */
 188             base = LOWORD(EBP_reg(context)) + LOWORD(EDI_reg(context));
 189             seg  = SS_reg(context);
 190             break;
 191         case 4:  /* ds:(si) */
 192             base = LOWORD(ESI_reg(context));
 193             seg  = DS_reg(context);
 194             break;
 195         case 5:  /* ds:(di) */
 196             base = LOWORD(EDI_reg(context));
 197             seg  = DS_reg(context);
 198             break;
 199         case 6:  /* ss:(bp) */
 200             base = LOWORD(EBP_reg(context));
 201             seg  = SS_reg(context);
 202             break;
 203         case 7:  /* ds:(bx) */
 204             base = LOWORD(EBX_reg(context));
 205             seg  = DS_reg(context);
 206             break;
 207         }
 208
 209         switch(mod)
 210         {
 211         case 0:
 212             if (rm == 6)  /* special case: ds:(disp16) */
 213             {
 214                 GET_VAL( &base, WORD );
 215                 seg  = DS_reg(context);
 216             }
 217             break;
 218
 219         case 1:  /* 8-bit disp */
 220             GET_VAL( &off, BYTE );
 221             base += (signed char)off;
 222             break;
 223
 224         case 2:  /* 16-bit disp */
 225             GET_VAL( &off, WORD );
 226             base += (signed short)off;
 227             break;
 228         }
 229         base &= 0xffff;
 230     }
 231     if (segprefix != -1) seg = segprefix;
 232
 233     /* Make sure the segment and offset are valid */
 234     if (IS_SELECTOR_SYSTEM(seg)) return (BYTE *)(base + (index << ss));
 235     if (((seg & 7) != 7) || IS_SELECTOR_FREE(seg)) return NULL;
 236     if (GET_SEL_LIMIT(seg) < (base + (index << ss))) return NULL;
 237     return (BYTE *)PTR_SEG_OFF_TO_LIN( seg, (base + (index << ss)) );
 238 #undef GET_VAL
 239 }
 240
 241
 242 /***********************************************************************
 243  *           INSTR_EmulateLDS
 244  *
 245  * Emulate the LDS (and LES,LFS,etc.) instruction.
 246  */
 247 static BOOL INSTR_EmulateLDS( CONTEXT86 *context, BYTE *instr, int long_op,
 248                               int long_addr, int segprefix, int *len )
 249 {
 250     WORD seg;
 251     BYTE *regmodrm = instr + 1 + (*instr == 0x0f);
 252     BYTE *addr = INSTR_GetOperandAddr( context, regmodrm,
 253                                        long_addr, segprefix, len );
 254     if (!addr)
 255         return FALSE;  /* Unable to emulate it */
 256     seg = *(WORD *)(addr + (long_op ? 4 : 2));
 257
 258     if (!INSTR_ReplaceSelector( context, &seg ))
 259         return FALSE;  /* Unable to emulate it */
 260
 261     /* Now store the offset in the correct register */
 262
 263     switch((*regmodrm >> 3) & 7)
 264     {
 265     case 0:
 266         if (long_op) EAX_reg(context) = *(DWORD *)addr;
 267         else SET_LOWORD(EAX_reg(context),*(WORD *)addr);
 268         break;
 269     case 1:
 270         if (long_op) ECX_reg(context) = *(DWORD *)addr;
 271         else SET_LOWORD(ECX_reg(context),*(WORD *)addr);
 272         break;
 273     case 2:
 274         if (long_op) EDX_reg(context) = *(DWORD *)addr;
 275         else SET_LOWORD(EDX_reg(context),*(WORD *)addr);
 276         break;
 277     case 3:
 278         if (long_op) EBX_reg(context) = *(DWORD *)addr;
 279         else SET_LOWORD(EBX_reg(context),*(WORD *)addr);
 280         break;
 281     case 4:
 282         if (long_op) ESP_reg(context) = *(DWORD *)addr;
 283         else SET_LOWORD(ESP_reg(context),*(WORD *)addr);
 284         break;
 285     case 5:
 286         if (long_op) EBP_reg(context) = *(DWORD *)addr;
 287         else SET_LOWORD(EBP_reg(context),*(WORD *)addr);
 288         break;
 289     case 6:
 290         if (long_op) ESI_reg(context) = *(DWORD *)addr;
 291         else SET_LOWORD(ESI_reg(context),*(WORD *)addr);
 292         break;
 293     case 7:
 294         if (long_op) EDI_reg(context) = *(DWORD *)addr;
 295         else SET_LOWORD(EDI_reg(context),*(WORD *)addr);
 296         break;
 297     }
 298
 299     /* Store the correct segment in the segment register */
 300
 301     switch(*instr)
 302     {
 303     case 0xc4: ES_reg(context) = seg; break;  /* les */
 304     case 0xc5: DS_reg(context) = seg; break;  /* lds */
 305     case 0x0f: switch(instr[1])
 306                {
 307                case 0xb2: SS_reg(context) = seg; break;  /* lss */
 308                case 0xb4: FS_reg(context) = seg; break;  /* lfs */
 309                case 0xb5: GS_reg(context) = seg; break;  /* lgs */
 310                }
 311                break;
 312     }
 313
 314     /* Add the opcode size to the total length */
 315
 316     *len += 1 + (*instr == 0x0f);
 317     return TRUE;
 318 }
 319
 320 /***********************************************************************
 321  *           INSTR_inport
 322  *
 323  * input on a I/O port
 324  */
 325 static DWORD INSTR_inport( WORD port, int size, CONTEXT86 *context )
 326 {
 327     DWORD res = IO_inport( port, size );
 328     if (TRACE_ON(io))
 329     {
 330         switch(size)
 331         {
 332         case 1:
 333             DPRINTF( "0x%x < %02x @ %04x:%04x\n", port, LOBYTE(res),
 334                      (WORD)CS_reg(context), LOWORD(EIP_reg(context)));
 335             break;
 336         case 2:
 337             DPRINTF( "0x%x < %04x @ %04x:%04x\n", port, LOWORD(res),
 338                      (WORD)CS_reg(context), LOWORD(EIP_reg(context)));
 339             break;
 340         case 4:
 341             DPRINTF( "0x%x < %08lx @ %04x:%04x\n", port, res,
 342                      (WORD)CS_reg(context), LOWORD(EIP_reg(context)));
 343             break;
 344         }
 345     }
 346     return res;
 347 }
 348
 349
 350 /***********************************************************************
 351  *           INSTR_outport
 352  *
 353  * output on a I/O port
 354  */
 355 static void INSTR_outport( WORD port, int size, DWORD val, CONTEXT86 *context )
 356 {
 357     IO_outport( port, size, val );
 358     if (TRACE_ON(io))
 359     {
 360         switch(size)
 361         {
 362         case 1:
 363             DPRINTF("0x%x > %02x @ %04x:%04x\n", port, LOBYTE(val),
 364                     (WORD)CS_reg(context), LOWORD(EIP_reg(context)));
 365             break;
 366         case 2:
 367             DPRINTF("0x%x > %04x @ %04x:%04x\n", port, LOWORD(val),
 368                     (WORD)CS_reg(context), LOWORD(EIP_reg(context)));
 369             break;
 370         case 4:
 371             DPRINTF("0x%x > %08lx @ %04x:%04x\n", port, val,
 372                     (WORD)CS_reg(context), LOWORD(EIP_reg(context)));
 373             break;
 374         }
 375     }
 376 }
 377
 378
 379 /***********************************************************************
 380  *           INSTR_EmulateInstruction
 381  *
 382  * Emulate a priviledged instruction. Returns TRUE if emulation successful.
 383  */
 384 BOOL INSTR_EmulateInstruction( CONTEXT86 *context )
 385 {
 386     int prefix, segprefix, prefixlen, len, repX, long_op, long_addr;
 387     SEGPTR gpHandler;
 388     BYTE *instr;
 389
 390     long_op = long_addr = IS_SEL_32(context,CS_reg(context));
 391     instr = (BYTE *)MK_PTR(context,CS_reg(context),EIP_reg(context));
 392     if (!instr) return FALSE;
 393
 394     /* First handle any possible prefix */
 395
 396     segprefix = -1;  /* no prefix */
 397     prefix = 1;
 398     repX = 0;
 399     prefixlen = 0;
 400     while(prefix)
 401     {
 402         switch(*instr)
 403         {
 404         case 0x2e:
 405             segprefix = CS_reg(context);
 406             break;
 407         case 0x36:
 408             segprefix = SS_reg(context);
 409             break;
 410         case 0x3e:
 411             segprefix = DS_reg(context);
 412             break;
 413         case 0x26:
 414             segprefix = ES_reg(context);
 415             break;
 416         case 0x64:
 417             segprefix = FS_reg(context);
 418             break;
 419         case 0x65:
 420             segprefix = GS_reg(context);
 421             break;
 422         case 0x66:
 423             long_op = !long_op;  /* opcode size prefix */
 424             break;
 425         case 0x67:
 426             long_addr = !long_addr;  /* addr size prefix */
 427             break;
 428         case 0xf0:  /* lock */
 429             break;
 430         case 0xf2:  /* repne */
 431             repX = 1;
 432             break;
 433         case 0xf3:  /* repe */
 434             repX = 2;
 435             break;
 436         default:
 437             prefix = 0;  /* no more prefixes */
 438             break;
 439         }
 440         if (prefix)
 441         {
 442             instr++;
 443             prefixlen++;
 444         }
 445     }
 446
 447     /* Now look at the actual instruction */
 448
 449     switch(*instr)
 450     {
 451         case 0x07: /* pop es */
 452         case 0x17: /* pop ss */
 453         case 0x1f: /* pop ds */
 454             {
 455                 WORD seg = *(WORD *)STACK_PTR( context );
 456                 if (INSTR_ReplaceSelector( context, &seg ))
 457                 {
 458                     switch(*instr)
 459                     {
 460                     case 0x07: ES_reg(context) = seg; break;
 461                     case 0x17: SS_reg(context) = seg; break;
 462                     case 0x1f: DS_reg(context) = seg; break;
 463                     }
 464                     ADD_STACK_reg(context, long_op ? 4 : 2);
 465                     EIP_reg(context) += prefixlen + 1;
 466                     return TRUE;
 467                 }
 468             }
 469             break;  /* Unable to emulate it */
 470
 471         case 0x0f: /* extended instruction */
 472             switch(instr[1])
 473             {
 474             case 0x22: /* mov eax, crX */
 475                 switch (instr[2]) {
 476                 case 0xc0:
 477                         ERR("mov eax,cr0 at 0x%08lx, EAX=0x%08lx\n",
 478                             EIP_reg(context),EAX_reg(context) );
 479                         EIP_reg(context) += prefixlen+3;
 480                         return TRUE;
 481                 default:
 482                         break; /*fallthrough to bad instruction handling */
 483                 }
 484                 break; /*fallthrough to bad instruction handling */
 485             case 0x20: /* mov crX, eax */
 486                 switch (instr[2]) {
 487                 case 0xe0: /* mov cr4, eax */
 488                     /* CR4 register . See linux/arch/i386/mm/init.c, X86_CR4_ defs
 489                      * bit 0: VME       Virtual Mode Exception ?
 490                      * bit 1: PVI       Protected mode Virtual Interrupt
 491                      * bit 2: TSD       Timestamp disable
 492                      * bit 3: DE        Debugging extensions
 493                      * bit 4: PSE       Page size extensions
 494                      * bit 5: PAE   Physical address extension
 495                      * bit 6: MCE       Machine check enable
 496                      * bit 7: PGE   Enable global pages
 497                      * bit 8: PCE       Enable performance counters at IPL3
 498                      */
 499                     ERR("mov cr4,eax at 0x%08lx\n",EIP_reg(context));
 500                     EAX_reg(context) = 0;
 501                     EIP_reg(context) += prefixlen+3;
 502                     return TRUE;
 503                 case 0xc0: /* mov cr0, eax */
 504                     ERR("mov cr0,eax at 0x%08lx\n",EIP_reg(context));
 505                     EAX_reg(context) = 0x10; /* FIXME: set more bits ? */
 506                     EIP_reg(context) += prefixlen+3;
 507                     return TRUE;
 508                 default: /* fallthrough to illegal instruction */
 509                     break;
 510                 }
 511                 /* fallthrough to illegal instruction */
 512                 break;
 513             case 0xa1: /* pop fs */
 514                 {
 515                     WORD seg = *(WORD *)STACK_PTR( context );
 516                     if (INSTR_ReplaceSelector( context, &seg ))
 517                     {
 518                         FS_reg(context) = seg;
 519                         ADD_STACK_reg(context, long_op ? 4 : 2);
 520                         EIP_reg(context) += prefixlen + 2;
 521                         return TRUE;
 522                     }
 523                 }
 524                 break;
 525             case 0xa9: /* pop gs */
 526                 {
 527                     WORD seg = *(WORD *)STACK_PTR( context );
 528                     if (INSTR_ReplaceSelector( context, &seg ))
 529                     {
 530                         GS_reg(context) = seg;
 531                         ADD_STACK_reg(context, long_op ? 4 : 2);
 532                         EIP_reg(context) += prefixlen + 2;
 533                         return TRUE;
 534                     }
 535                 }
 536                 break;
 537             case 0xb2: /* lss addr,reg */
 538             case 0xb4: /* lfs addr,reg */
 539             case 0xb5: /* lgs addr,reg */
 540                 if (INSTR_EmulateLDS( context, instr, long_op,
 541                                       long_addr, segprefix, &len ))
 542                 {
 543                     EIP_reg(context) += prefixlen + len;
 544                     return TRUE;
 545                 }
 546                 break;
 547             }
 548             break;  /* Unable to emulate it */
 549
 550         case 0x6c: /* insb     */
 551         case 0x6d: /* insw/d   */
 552         case 0x6e: /* outsb    */
 553         case 0x6f: /* outsw/d  */
 554             {
 555               int typ = *instr;  /* Just in case it's overwritten.  */
 556               int outp = (typ >= 0x6e);
 557               unsigned long count = repX ?
 558                           (long_addr ? ECX_reg(context) : LOWORD(ECX_reg(context))) : 1;
 559               int opsize = (typ & 1) ? (long_op ? 4 : 2) : 1;
 560               int step = (EFL_reg(context) & 0x400) ? -opsize : +opsize;
 561               int seg = outp ? DS_reg(context) : ES_reg(context);  /* FIXME: is this right? */
 562
 563               if (outp)
 564                 /* FIXME: Check segment readable.  */
 565                 (void)0;
 566               else
 567                 /* FIXME: Check segment writeable.  */
 568                 (void)0;
 569
 570               if (repX)
 571               {
 572                 if (long_addr) ECX_reg(context) = 0;
 573                 else SET_LOWORD(ECX_reg(context),0);
 574               }
 575
 576               while (count-- > 0)
 577                 {
 578                   void *data;
 579                   WORD dx = LOWORD(EDX_reg(context));
 580                   if (outp)
 581                   {
 582                       data = MK_PTR(context, seg,
 583                                     long_addr ? ESI_reg(context) : LOWORD(ESI_reg(context)));
 584                       if (long_addr) ESI_reg(context) += step;
 585                       else ADD_LOWORD(ESI_reg(context),step);
 586                   }
 587                   else
 588                   {
 589                       data = MK_PTR(context, seg,
 590                                     long_addr ? EDI_reg(context) : LOWORD(EDI_reg(context)));
 591                       if (long_addr) EDI_reg(context) += step;
 592                       else ADD_LOWORD(EDI_reg(context),step);
 593                   }
 594
 595                   switch (typ)
 596                   {
 597                     case 0x6c:
 598                       *(BYTE *)data = INSTR_inport( dx, 1, context );
 599                       break;
 600                     case 0x6d:
 601                       if (long_op)
 602                           *(DWORD *)data = INSTR_inport( dx, 4, context );
 603                       else
 604                           *(WORD *)data = INSTR_inport( dx, 2, context );
 605                       break;
 606                     case 0x6e:
 607                         INSTR_outport( dx, 1, *(BYTE *)data, context );
 608                         break;
 609                     case 0x6f:
 610                         if (long_op)
 611                             INSTR_outport( dx, 4, *(DWORD *)data, context );
 612                         else
 613                             INSTR_outport( dx, 2, *(WORD *)data, context );
 614                         break;
 615                     }
 616                 }
 617               EIP_reg(context) += prefixlen + 1;
 618             }
 619             return TRUE;
 620
 621         case 0x8e: /* mov XX,segment_reg */
 622             {
 623                 WORD seg;
 624                 BYTE *addr = INSTR_GetOperandAddr(context, instr + 1,
 625                                                   long_addr, segprefix, &len );
 626                 if (!addr)
 627                     break;  /* Unable to emulate it */
 628                 seg = *(WORD *)addr;
 629                 if (!INSTR_ReplaceSelector( context, &seg ))
 630                     break;  /* Unable to emulate it */
 631
 632                 switch((instr[1] >> 3) & 7)
 633                 {
 634                 case 0:
 635                     ES_reg(context) = seg;
 636                     EIP_reg(context) += prefixlen + len + 1;
 637                     return TRUE;
 638                 case 1:  /* cs */
 639                     break;
 640                 case 2:
 641                     SS_reg(context) = seg;
 642                     EIP_reg(context) += prefixlen + len + 1;
 643                     return TRUE;
 644                 case 3:
 645                     DS_reg(context) = seg;
 646                     EIP_reg(context) += prefixlen + len + 1;
 647                     return TRUE;
 648                 case 4:
 649                     FS_reg(context) = seg;
 650                     EIP_reg(context) += prefixlen + len + 1;
 651                     return TRUE;
 652                 case 5:
 653                     GS_reg(context) = seg;
 654                     EIP_reg(context) += prefixlen + len + 1;
 655                     return TRUE;
 656                 case 6:  /* unused */
 657                 case 7:  /* unused */
 658                     break;
 659                 }
 660             }
 661             break;  /* Unable to emulate it */
 662
 663         case 0xc4: /* les addr,reg */
 664         case 0xc5: /* lds addr,reg */
 665             if (INSTR_EmulateLDS( context, instr, long_op,
 666                                   long_addr, segprefix, &len ))
 667             {
 668                 EIP_reg(context) += prefixlen + len;
 669                 return TRUE;
 670             }
 671             break;  /* Unable to emulate it */
 672
 673         case 0xcd: /* int <XX> */
 674             if (long_op)
 675             {
 676                 ERR("int xx from 32-bit code is not supported.\n");
 677                 break;  /* Unable to emulate it */
 678             }
 679             else
 680             {
 681                 FARPROC16 addr = INT_GetPMHandler( instr[1] );
 682                 WORD *stack = (WORD *)STACK_PTR( context );
 683                 if (!addr)
 684                 {
 685                     FIXME("no handler for interrupt %02x, ignoring it\n", instr[1]);
 686                     EIP_reg(context) += prefixlen + 2;
 687                     return TRUE;
 688                 }
 689                 /* Push the flags and return address on the stack */
 690                 *(--stack) = LOWORD(EFL_reg(context));
 691                 *(--stack) = CS_reg(context);
 692                 *(--stack) = LOWORD(EIP_reg(context)) + prefixlen + 2;
 693                 ADD_STACK_reg(context, -3 * sizeof(WORD));
 694                 /* Jump to the interrupt handler */
 695                 CS_reg(context)  = HIWORD(addr);
 696                 EIP_reg(context) = LOWORD(addr);
 697             }
 698             return TRUE;
 699
 700         case 0xcf: /* iret */
 701             if (long_op)
 702             {
 703                 DWORD *stack = (DWORD *)STACK_PTR( context );
 704                 EIP_reg(context) = *stack++;
 705                 CS_reg(context)  = *stack++;
 706                 EFL_reg(context) = *stack;
 707                 ADD_STACK_reg(context, 3*sizeof(DWORD));  /* Pop the return address and flags */
 708             }
 709             else
 710             {
 711                 WORD *stack = (WORD *)STACK_PTR( context );
 712                 EIP_reg(context) = *stack++;
 713                 CS_reg(context)  = *stack++;
 714                 SET_LOWORD(EFL_reg(context),*stack);
 715                 ADD_STACK_reg(context, 3*sizeof(WORD));  /* Pop the return address and flags */
 716             }
 717             return TRUE;
 718
 719         case 0xe4: /* inb al,XX */
 720             SET_LOBYTE(EAX_reg(context),INSTR_inport( instr[1], 1, context ));
 721             EIP_reg(context) += prefixlen + 2;
 722             return TRUE;
 723
 724         case 0xe5: /* in (e)ax,XX */
 725             if (long_op)
 726                 EAX_reg(context) = INSTR_inport( instr[1], 4, context );
 727             else
 728                 SET_LOWORD(EAX_reg(context), INSTR_inport( instr[1], 2, context ));
 729             EIP_reg(context) += prefixlen + 2;
 730             return TRUE;
 731
 732         case 0xe6: /* outb XX,al */
 733             INSTR_outport( instr[1], 1, LOBYTE(EAX_reg(context)), context );
 734             EIP_reg(context) += prefixlen + 2;
 735             return TRUE;
 736
 737         case 0xe7: /* out XX,(e)ax */
 738             if (long_op)
 739                 INSTR_outport( instr[1], 4, EAX_reg(context), context );
 740             else
 741                 INSTR_outport( instr[1], 2, LOWORD(EAX_reg(context)), context );
 742             EIP_reg(context) += prefixlen + 2;
 743             return TRUE;
 744
 745         case 0xec: /* inb al,dx */
 746             SET_LOBYTE(EAX_reg(context), INSTR_inport( LOWORD(EDX_reg(context)), 1, context ) );
 747             EIP_reg(context) += prefixlen + 1;
 748             return TRUE;
 749
 750         case 0xed: /* in (e)ax,dx */
 751             if (long_op)
 752                 EAX_reg(context) = INSTR_inport( LOWORD(EDX_reg(context)), 4, context );
 753             else
 754                 SET_LOWORD(EAX_reg(context), INSTR_inport( LOWORD(EDX_reg(context)), 2, context ));
 755             EIP_reg(context) += prefixlen + 1;
 756             return TRUE;
 757
 758         case 0xee: /* outb dx,al */
 759             INSTR_outport( LOWORD(EDX_reg(context)), 1, LOBYTE(EAX_reg(context)), context );
 760             EIP_reg(context) += prefixlen + 1;
 761             return TRUE;
 762
 763         case 0xef: /* out dx,(e)ax */
 764             if (long_op)
 765                 INSTR_outport( LOWORD(EDX_reg(context)), 4, EAX_reg(context), context );
 766             else
 767                 INSTR_outport( LOWORD(EDX_reg(context)), 2, LOWORD(EAX_reg(context)), context );
 768             EIP_reg(context) += prefixlen + 1;
 769             return TRUE;
 770
 771         case 0xfa: /* cli, ignored */
 772             EIP_reg(context) += prefixlen + 1;
 773             return TRUE;
 774
 775         case 0xfb: /* sti, ignored */
 776             EIP_reg(context) += prefixlen + 1;
 777             return TRUE;
 778     }
 779
 780
 781     /* Check for Win16 __GP handler */
 782     gpHandler = HasGPHandler16( PTR_SEG_OFF_TO_SEGPTR( CS_reg(context),
 783                                                        EIP_reg(context) ) );
 784     if (gpHandler)
 785     {
 786         WORD *stack = (WORD *)STACK_PTR( context );
 787         *--stack = CS_reg(context);
 788         *--stack = EIP_reg(context);
 789         ADD_STACK_reg(context, -2*sizeof(WORD));
 790
 791         CS_reg(context) = SELECTOROF( gpHandler );
 792         EIP_reg(context) = OFFSETOF( gpHandler );
 793         return TRUE;
 794     }
 795     return FALSE;  /* Unable to emulate it */
 796 }
 797
 798 #endif  /* __i386__ */