memory/instr.c

   1 /*
   2  * Emulation of privileged instructions
   3  *
   4  * Copyright 1995 Alexandre Julliard
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  */
  20
  21 #include "windef.h"
  22 #include "wingdi.h"
  23 #include "wine/winuser16.h"
  24 #include "module.h"
  25 #include "miscemu.h"
  26 #include "selectors.h"
  27 #include "wine/debug.h"
  28 #include "callback.h"
  29 #include "thread.h"
  30 #include "wine/exception.h"
  31
  32 WINE_DEFAULT_DEBUG_CHANNEL(int);
  33 WINE_DECLARE_DEBUG_CHANNEL(io);
  34
  35 #ifdef __i386__
  36
  37 /* macros to set parts of a DWORD */
  38 #define SET_LOWORD(dw,val)  ((dw) = ((dw) & 0xffff0000) | LOWORD(val))
  39 #define SET_LOBYTE(dw,val)  ((dw) = ((dw) & 0xffffff00) | LOBYTE(val))
  40 #define ADD_LOWORD(dw,val)  ((dw) = ((dw) & 0xffff0000) | LOWORD((DWORD)(dw)+(val)))
  41
  42 inline static void add_stack( CONTEXT86 *context, int offset )
  43 {
  44     if (ISV86(context) || !IS_SELECTOR_32BIT(context->SegSs))
  45         ADD_LOWORD( context->Esp, offset );
  46     else
  47         context->Esp += offset;
  48 }
  49
  50 inline static void *make_ptr( CONTEXT86 *context, DWORD seg, DWORD off, int long_addr )
  51 {
  52     if (ISV86(context)) return PTR_REAL_TO_LIN( seg, off );
  53     if (IS_SELECTOR_SYSTEM(seg)) return (void *)off;
  54     if (!long_addr) off = LOWORD(off);
  55     return (char *) MapSL( MAKESEGPTR( seg, 0 ) ) + off;
  56 }
  57
  58 inline static void *get_stack( CONTEXT86 *context )
  59 {
  60     if (ISV86(context)) return PTR_REAL_TO_LIN( context->SegSs, context->Esp );
  61     return wine_ldt_get_ptr( context->SegSs, context->Esp );
  62 }
  63
  64
  65 /***********************************************************************
  66  *           timer_thread
  67  */
  68 static DWORD CALLBACK timer_thread( void *dummy )
  69 {
  70     for (;;)
  71     {
  72         Sleep(55);
  73         DOSMEM_Tick( 0 );
  74     }
  75 }
  76
  77 /***********************************************************************
  78  *           INSTR_ReplaceSelector
  79  *
  80  * Try to replace an invalid selector by a valid one.
  81  * The only selector where it is allowed to do "mov ax,40;mov es,ax"
  82  * is the so called 'bimodal' selector 0x40, which points to the BIOS
  83  * data segment. Used by (at least) Borland products (and programs compiled
  84  * using Borland products).
  85  *
  86  * See Undocumented Windows, Chapter 5, __0040.
  87  */
  88 static BOOL INSTR_ReplaceSelector( CONTEXT86 *context, WORD *sel )
  89 {
  90     if (*sel == 0x40)
  91     {
  92 #if 0  /* hack until this is moved to kernel */
  93         static WORD sys_timer = 0;
  94         if (!sys_timer)
  95             sys_timer = CreateSystemTimer( 55, DOSMEM_Tick );
  96 #endif
  97         static HANDLE sys_thread;
  98         if (!sys_thread) sys_thread = CreateThread( NULL, 0, timer_thread, NULL, 0, NULL );
  99         *sel = DOSMEM_BiosDataSeg;
 100         return TRUE;
 101     }
 102     return FALSE;  /* Can't replace selector, crashdump */
 103 }
 104
 105
 106 /***********************************************************************
 107  *           INSTR_GetOperandAddr
 108  *
 109  * Return the address of an instruction operand (from the mod/rm byte).
 110  */
 111 static BYTE *INSTR_GetOperandAddr( CONTEXT86 *context, BYTE *instr,
 112                                    int long_addr, int segprefix, int *len )
 113 {
 114     int mod, rm, base, index = 0, ss = 0, seg = 0, off;
 115     LDT_ENTRY entry;
 116
 117 #define GET_VAL(val,type) \
 118     { *val = *(type *)instr; instr += sizeof(type); *len += sizeof(type); }
 119
 120     *len = 0;
 121     GET_VAL( &mod, BYTE );
 122     rm = mod & 7;
 123     mod >>= 6;
 124
 125     if (mod == 3)
 126     {
 127         switch(rm)
 128         {
 129         case 0: return (BYTE *)&context->Eax;
 130         case 1: return (BYTE *)&context->Ecx;
 131         case 2: return (BYTE *)&context->Edx;
 132         case 3: return (BYTE *)&context->Ebx;
 133         case 4: return (BYTE *)&context->Esp;
 134         case 5: return (BYTE *)&context->Ebp;
 135         case 6: return (BYTE *)&context->Esi;
 136         case 7: return (BYTE *)&context->Edi;
 137         }
 138     }
 139
 140     if (long_addr)
 141     {
 142         if (rm == 4)
 143         {
 144             BYTE sib;
 145             GET_VAL( &sib, BYTE );
 146             rm = sib & 7;
 147             ss = sib >> 6;
 148             switch(sib >> 3)
 149             {
 150             case 0: index = context->Eax; break;
 151             case 1: index = context->Ecx; break;
 152             case 2: index = context->Edx; break;
 153             case 3: index = context->Ebx; break;
 154             case 4: index = 0; break;
 155             case 5: index = context->Ebp; break;
 156             case 6: index = context->Esi; break;
 157             case 7: index = context->Edi; break;
 158             }
 159         }
 160
 161         switch(rm)
 162         {
 163         case 0: base = context->Eax; seg = context->SegDs; break;
 164         case 1: base = context->Ecx; seg = context->SegDs; break;
 165         case 2: base = context->Edx; seg = context->SegDs; break;
 166         case 3: base = context->Ebx; seg = context->SegDs; break;
 167         case 4: base = context->Esp; seg = context->SegSs; break;
 168         case 5: base = context->Ebp; seg = context->SegSs; break;
 169         case 6: base = context->Esi; seg = context->SegDs; break;
 170         case 7: base = context->Edi; seg = context->SegDs; break;
 171         }
 172         switch (mod)
 173         {
 174         case 0:
 175             if (rm == 5)  /* special case: ds:(disp32) */
 176             {
 177                 GET_VAL( &base, DWORD );
 178                 seg = context->SegDs;
 179             }
 180             break;
 181
 182         case 1:  /* 8-bit disp */
 183             GET_VAL( &off, BYTE );
 184             base += (signed char)off;
 185             break;
 186
 187         case 2:  /* 32-bit disp */
 188             GET_VAL( &off, DWORD );
 189             base += (signed long)off;
 190             break;
 191         }
 192     }
 193     else  /* short address */
 194     {
 195         switch(rm)
 196         {
 197         case 0:  /* ds:(bx,si) */
 198             base = LOWORD(context->Ebx) + LOWORD(context->Esi);
 199             seg  = context->SegDs;
 200             break;
 201         case 1:  /* ds:(bx,di) */
 202             base = LOWORD(context->Ebx) + LOWORD(context->Edi);
 203             seg  = context->SegDs;
 204             break;
 205         case 2:  /* ss:(bp,si) */
 206             base = LOWORD(context->Ebp) + LOWORD(context->Esi);
 207             seg  = context->SegSs;
 208             break;
 209         case 3:  /* ss:(bp,di) */
 210             base = LOWORD(context->Ebp) + LOWORD(context->Edi);
 211             seg  = context->SegSs;
 212             break;
 213         case 4:  /* ds:(si) */
 214             base = LOWORD(context->Esi);
 215             seg  = context->SegDs;
 216             break;
 217         case 5:  /* ds:(di) */
 218             base = LOWORD(context->Edi);
 219             seg  = context->SegDs;
 220             break;
 221         case 6:  /* ss:(bp) */
 222             base = LOWORD(context->Ebp);
 223             seg  = context->SegSs;
 224             break;
 225         case 7:  /* ds:(bx) */
 226             base = LOWORD(context->Ebx);
 227             seg  = context->SegDs;
 228             break;
 229         }
 230
 231         switch(mod)
 232         {
 233         case 0:
 234             if (rm == 6)  /* special case: ds:(disp16) */
 235             {
 236                 GET_VAL( &base, WORD );
 237                 seg  = context->SegDs;
 238             }
 239             break;
 240
 241         case 1:  /* 8-bit disp */
 242             GET_VAL( &off, BYTE );
 243             base += (signed char)off;
 244             break;
 245
 246         case 2:  /* 16-bit disp */
 247             GET_VAL( &off, WORD );
 248             base += (signed short)off;
 249             break;
 250         }
 251         base &= 0xffff;
 252     }
 253     if (segprefix != -1) seg = segprefix;
 254
 255     /* Make sure the segment and offset are valid */
 256     if (IS_SELECTOR_SYSTEM(seg)) return (BYTE *)(base + (index << ss));
 257     if ((seg & 7) != 7) return NULL;
 258     wine_ldt_get_entry( seg, &entry );
 259     if (wine_ldt_is_empty( &entry )) return NULL;
 260     if (wine_ldt_get_limit(&entry) < (base + (index << ss))) return NULL;
 261     return (char *)wine_ldt_get_base(&entry) + base + (index << ss);
 262 #undef GET_VAL
 263 }
 264
 265
 266 /***********************************************************************
 267  *           INSTR_EmulateLDS
 268  *
 269  * Emulate the LDS (and LES,LFS,etc.) instruction.
 270  */
 271 static BOOL INSTR_EmulateLDS( CONTEXT86 *context, BYTE *instr, int long_op,
 272                               int long_addr, int segprefix, int *len )
 273 {
 274     WORD seg;
 275     BYTE *regmodrm = instr + 1 + (*instr == 0x0f);
 276     BYTE *addr = INSTR_GetOperandAddr( context, regmodrm,
 277                                        long_addr, segprefix, len );
 278     if (!addr)
 279         return FALSE;  /* Unable to emulate it */
 280     seg = *(WORD *)(addr + (long_op ? 4 : 2));
 281
 282     if (!INSTR_ReplaceSelector( context, &seg ))
 283         return FALSE;  /* Unable to emulate it */
 284
 285     /* Now store the offset in the correct register */
 286
 287     switch((*regmodrm >> 3) & 7)
 288     {
 289     case 0:
 290         if (long_op) context->Eax = *(DWORD *)addr;
 291         else SET_LOWORD(context->Eax,*(WORD *)addr);
 292         break;
 293     case 1:
 294         if (long_op) context->Ecx = *(DWORD *)addr;
 295         else SET_LOWORD(context->Ecx,*(WORD *)addr);
 296         break;
 297     case 2:
 298         if (long_op) context->Edx = *(DWORD *)addr;
 299         else SET_LOWORD(context->Edx,*(WORD *)addr);
 300         break;
 301     case 3:
 302         if (long_op) context->Ebx = *(DWORD *)addr;
 303         else SET_LOWORD(context->Ebx,*(WORD *)addr);
 304         break;
 305     case 4:
 306         if (long_op) context->Esp = *(DWORD *)addr;
 307         else SET_LOWORD(context->Esp,*(WORD *)addr);
 308         break;
 309     case 5:
 310         if (long_op) context->Ebp = *(DWORD *)addr;
 311         else SET_LOWORD(context->Ebp,*(WORD *)addr);
 312         break;
 313     case 6:
 314         if (long_op) context->Esi = *(DWORD *)addr;
 315         else SET_LOWORD(context->Esi,*(WORD *)addr);
 316         break;
 317     case 7:
 318         if (long_op) context->Edi = *(DWORD *)addr;
 319         else SET_LOWORD(context->Edi,*(WORD *)addr);
 320         break;
 321     }
 322
 323     /* Store the correct segment in the segment register */
 324
 325     switch(*instr)
 326     {
 327     case 0xc4: context->SegEs = seg; break;  /* les */
 328     case 0xc5: context->SegDs = seg; break;  /* lds */
 329     case 0x0f: switch(instr[1])
 330                {
 331                case 0xb2: context->SegSs = seg; break;  /* lss */
 332                case 0xb4: context->SegFs = seg; break;  /* lfs */
 333                case 0xb5: context->SegGs = seg; break;  /* lgs */
 334                }
 335                break;
 336     }
 337
 338     /* Add the opcode size to the total length */
 339
 340     *len += 1 + (*instr == 0x0f);
 341     return TRUE;
 342 }
 343
 344 /***********************************************************************
 345  *           INSTR_inport
 346  *
 347  * input on a I/O port
 348  */
 349 static DWORD INSTR_inport( WORD port, int size, CONTEXT86 *context )
 350 {
 351     DWORD res = IO_inport( port, size );
 352     if (TRACE_ON(io))
 353     {
 354         switch(size)
 355         {
 356         case 1:
 357             DPRINTF( "0x%x < %02x @ %04x:%04x\n", port, LOBYTE(res),
 358                      (WORD)context->SegCs, LOWORD(context->Eip));
 359             break;
 360         case 2:
 361             DPRINTF( "0x%x < %04x @ %04x:%04x\n", port, LOWORD(res),
 362                      (WORD)context->SegCs, LOWORD(context->Eip));
 363             break;
 364         case 4:
 365             DPRINTF( "0x%x < %08lx @ %04x:%04x\n", port, res,
 366                      (WORD)context->SegCs, LOWORD(context->Eip));
 367             break;
 368         }
 369     }
 370     return res;
 371 }
 372
 373
 374 /***********************************************************************
 375  *           INSTR_outport
 376  *
 377  * output on a I/O port
 378  */
 379 static void INSTR_outport( WORD port, int size, DWORD val, CONTEXT86 *context )
 380 {
 381     IO_outport( port, size, val );
 382     if (TRACE_ON(io))
 383     {
 384         switch(size)
 385         {
 386         case 1:
 387             DPRINTF("0x%x > %02x @ %04x:%04x\n", port, LOBYTE(val),
 388                     (WORD)context->SegCs, LOWORD(context->Eip));
 389             break;
 390         case 2:
 391             DPRINTF("0x%x > %04x @ %04x:%04x\n", port, LOWORD(val),
 392                     (WORD)context->SegCs, LOWORD(context->Eip));
 393             break;
 394         case 4:
 395             DPRINTF("0x%x > %08lx @ %04x:%04x\n", port, val,
 396                     (WORD)context->SegCs, LOWORD(context->Eip));
 397             break;
 398         }
 399     }
 400 }
 401
 402
 403 /***********************************************************************
 404  *           INSTR_EmulateInstruction
 405  *
 406  * Emulate a privileged instruction.
 407  * Returns exception code, or 0 if emulation successful.
 408  */
 409 DWORD INSTR_EmulateInstruction( CONTEXT86 *context )
 410 {
 411     int prefix, segprefix, prefixlen, len, repX, long_op, long_addr;
 412     BYTE *instr;
 413     DWORD ret = EXCEPTION_PRIV_INSTRUCTION;
 414
 415     long_op = long_addr = (!ISV86(context) && IS_SELECTOR_32BIT(context->SegCs));
 416     instr = make_ptr( context, context->SegCs, context->Eip, TRUE );
 417     if (!instr) return ret;
 418
 419     /* First handle any possible prefix */
 420
 421     segprefix = -1;  /* no prefix */
 422     prefix = 1;
 423     repX = 0;
 424     prefixlen = 0;
 425     while(prefix)
 426     {
 427         switch(*instr)
 428         {
 429         case 0x2e:
 430             segprefix = context->SegCs;
 431             break;
 432         case 0x36:
 433             segprefix = context->SegSs;
 434             break;
 435         case 0x3e:
 436             segprefix = context->SegDs;
 437             break;
 438         case 0x26:
 439             segprefix = context->SegEs;
 440             break;
 441         case 0x64:
 442             segprefix = context->SegFs;
 443             break;
 444         case 0x65:
 445             segprefix = context->SegGs;
 446             break;
 447         case 0x66:
 448             long_op = !long_op;  /* opcode size prefix */
 449             break;
 450         case 0x67:
 451             long_addr = !long_addr;  /* addr size prefix */
 452             break;
 453         case 0xf0:  /* lock */
 454             break;
 455         case 0xf2:  /* repne */
 456             repX = 1;
 457             break;
 458         case 0xf3:  /* repe */
 459             repX = 2;
 460             break;
 461         default:
 462             prefix = 0;  /* no more prefixes */
 463             break;
 464         }
 465         if (prefix)
 466         {
 467             instr++;
 468             prefixlen++;
 469         }
 470     }
 471
 472     /* Now look at the actual instruction */
 473
 474     switch(*instr)
 475     {
 476         case 0x07: /* pop es */
 477         case 0x17: /* pop ss */
 478         case 0x1f: /* pop ds */
 479             {
 480                 WORD seg = *(WORD *)get_stack( context );
 481                 if (INSTR_ReplaceSelector( context, &seg ))
 482                 {
 483                     switch(*instr)
 484                     {
 485                     case 0x07: context->SegEs = seg; break;
 486                     case 0x17: context->SegSs = seg; break;
 487                     case 0x1f: context->SegDs = seg; break;
 488                     }
 489                     add_stack(context, long_op ? 4 : 2);
 490                     context->Eip += prefixlen + 1;
 491                     return 0;
 492                 }
 493             }
 494             break;  /* Unable to emulate it */
 495
 496         case 0x0f: /* extended instruction */
 497             switch(instr[1])
 498             {
 499             case 0x22: /* mov eax, crX */
 500                 switch (instr[2]) {
 501                 case 0xc0:
 502                         ERR("mov eax,cr0 at 0x%08lx, EAX=0x%08lx\n",
 503                             context->Eip,context->Eax );
 504                         context->Eip += prefixlen+3;
 505                         return 0;
 506                 default:
 507                         break; /*fallthrough to bad instruction handling */
 508                 }
 509                 break; /*fallthrough to bad instruction handling */
 510             case 0x20: /* mov crX, eax */
 511                 switch (instr[2]) {
 512                 case 0xe0: /* mov cr4, eax */
 513                     /* CR4 register . See linux/arch/i386/mm/init.c, X86_CR4_ defs
 514                      * bit 0: VME       Virtual Mode Exception ?
 515                      * bit 1: PVI       Protected mode Virtual Interrupt
 516                      * bit 2: TSD       Timestamp disable
 517                      * bit 3: DE        Debugging extensions
 518                      * bit 4: PSE       Page size extensions
 519                      * bit 5: PAE   Physical address extension
 520                      * bit 6: MCE       Machine check enable
 521                      * bit 7: PGE   Enable global pages
 522                      * bit 8: PCE       Enable performance counters at IPL3
 523                      */
 524                     ERR("mov cr4,eax at 0x%08lx\n",context->Eip);
 525                     context->Eax = 0;
 526                     context->Eip += prefixlen+3;
 527                     return 0;
 528                 case 0xc0: /* mov cr0, eax */
 529                     ERR("mov cr0,eax at 0x%08lx\n",context->Eip);
 530                     context->Eax = 0x10; /* FIXME: set more bits ? */
 531                     context->Eip += prefixlen+3;
 532                     return 0;
 533                 default: /* fallthrough to illegal instruction */
 534                     break;
 535                 }
 536                 /* fallthrough to illegal instruction */
 537                 break;
 538             case 0xa1: /* pop fs */
 539                 {
 540                     WORD seg = *(WORD *)get_stack( context );
 541                     if (INSTR_ReplaceSelector( context, &seg ))
 542                     {
 543                         context->SegFs = seg;
 544                         add_stack(context, long_op ? 4 : 2);
 545                         context->Eip += prefixlen + 2;
 546                         return 0;
 547                     }
 548                 }
 549                 break;
 550             case 0xa9: /* pop gs */
 551                 {
 552                     WORD seg = *(WORD *)get_stack( context );
 553                     if (INSTR_ReplaceSelector( context, &seg ))
 554                     {
 555                         context->SegGs = seg;
 556                         add_stack(context, long_op ? 4 : 2);
 557                         context->Eip += prefixlen + 2;
 558                         return 0;
 559                     }
 560                 }
 561                 break;
 562             case 0xb2: /* lss addr,reg */
 563             case 0xb4: /* lfs addr,reg */
 564             case 0xb5: /* lgs addr,reg */
 565                 if (INSTR_EmulateLDS( context, instr, long_op,
 566                                       long_addr, segprefix, &len ))
 567                 {
 568                     context->Eip += prefixlen + len;
 569                     return 0;
 570                 }
 571                 break;
 572             }
 573             break;  /* Unable to emulate it */
 574
 575         case 0x6c: /* insb     */
 576         case 0x6d: /* insw/d   */
 577         case 0x6e: /* outsb    */
 578         case 0x6f: /* outsw/d  */
 579             {
 580               int typ = *instr;  /* Just in case it's overwritten.  */
 581               int outp = (typ >= 0x6e);
 582               unsigned long count = repX ?
 583                           (long_addr ? context->Ecx : LOWORD(context->Ecx)) : 1;
 584               int opsize = (typ & 1) ? (long_op ? 4 : 2) : 1;
 585               int step = (context->EFlags & 0x400) ? -opsize : +opsize;
 586               int seg = outp ? context->SegDs : context->SegEs;  /* FIXME: is this right? */
 587
 588               if (outp)
 589                 /* FIXME: Check segment readable.  */
 590                 (void)0;
 591               else
 592                 /* FIXME: Check segment writeable.  */
 593                 (void)0;
 594
 595               if (repX)
 596               {
 597                 if (long_addr) context->Ecx = 0;
 598                 else SET_LOWORD(context->Ecx,0);
 599               }
 600
 601               while (count-- > 0)
 602                 {
 603                   void *data;
 604                   WORD dx = LOWORD(context->Edx);
 605                   if (outp)
 606                   {
 607                       data = make_ptr( context, seg, context->Esi, long_addr );
 608                       if (long_addr) context->Esi += step;
 609                       else ADD_LOWORD(context->Esi,step);
 610                   }
 611                   else
 612                   {
 613                       data = make_ptr( context, seg, context->Edi, long_addr );
 614                       if (long_addr) context->Edi += step;
 615                       else ADD_LOWORD(context->Edi,step);
 616                   }
 617
 618                   switch (typ)
 619                   {
 620                     case 0x6c:
 621                       *(BYTE *)data = INSTR_inport( dx, 1, context );
 622                       break;
 623                     case 0x6d:
 624                       if (long_op)
 625                           *(DWORD *)data = INSTR_inport( dx, 4, context );
 626                       else
 627                           *(WORD *)data = INSTR_inport( dx, 2, context );
 628                       break;
 629                     case 0x6e:
 630                         INSTR_outport( dx, 1, *(BYTE *)data, context );
 631                         break;
 632                     case 0x6f:
 633                         if (long_op)
 634                             INSTR_outport( dx, 4, *(DWORD *)data, context );
 635                         else
 636                             INSTR_outport( dx, 2, *(WORD *)data, context );
 637                         break;
 638                     }
 639                 }
 640               context->Eip += prefixlen + 1;
 641             }
 642             return 0;
 643
 644         case 0x8e: /* mov XX,segment_reg */
 645             {
 646                 WORD seg;
 647                 BYTE *addr = INSTR_GetOperandAddr(context, instr + 1,
 648                                                   long_addr, segprefix, &len );
 649                 if (!addr)
 650                     break;  /* Unable to emulate it */
 651                 seg = *(WORD *)addr;
 652                 if (!INSTR_ReplaceSelector( context, &seg ))
 653                     break;  /* Unable to emulate it */
 654
 655                 switch((instr[1] >> 3) & 7)
 656                 {
 657                 case 0:
 658                     context->SegEs = seg;
 659                     context->Eip += prefixlen + len + 1;
 660                     return 0;
 661                 case 1:  /* cs */
 662                     break;
 663                 case 2:
 664                     context->SegSs = seg;
 665                     context->Eip += prefixlen + len + 1;
 666                     return 0;
 667                 case 3:
 668                     context->SegDs = seg;
 669                     context->Eip += prefixlen + len + 1;
 670                     return 0;
 671                 case 4:
 672                     context->SegFs = seg;
 673                     context->Eip += prefixlen + len + 1;
 674                     return 0;
 675                 case 5:
 676                     context->SegGs = seg;
 677                     context->Eip += prefixlen + len + 1;
 678                     return 0;
 679                 case 6:  /* unused */
 680                 case 7:  /* unused */
 681                     break;
 682                 }
 683             }
 684             break;  /* Unable to emulate it */
 685
 686         case 0xc4: /* les addr,reg */
 687         case 0xc5: /* lds addr,reg */
 688             if (INSTR_EmulateLDS( context, instr, long_op,
 689                                   long_addr, segprefix, &len ))
 690             {
 691                 context->Eip += prefixlen + len;
 692                 return 0;
 693             }
 694             break;  /* Unable to emulate it */
 695
 696         case 0xcd: /* int <XX> */
 697             if (IS_SELECTOR_SYSTEM(context->SegCs))
 698             {
 699                 /* Win32 applications cannot use interrupts */
 700                 ret = EXCEPTION_ACCESS_VIOLATION;
 701                 break;
 702             }
 703             else if (!Dosvm.EmulateInterruptPM && !DPMI_LoadDosSystem())
 704             {
 705                 ERR("could not initialize interrupt handling\n");
 706             }
 707             else
 708             {
 709                 context->Eip += prefixlen + 2;
 710                 Dosvm.EmulateInterruptPM( context, instr[1] );
 711                 return 0;
 712             }
 713             break;  /* Unable to emulate it */
 714
 715         case 0xcf: /* iret */
 716             if (long_op)
 717             {
 718                 DWORD *stack = get_stack( context );
 719                 context->Eip = *stack++;
 720                 context->SegCs  = *stack++;
 721                 context->EFlags = *stack;
 722                 add_stack(context, 3*sizeof(DWORD));  /* Pop the return address and flags */
 723             }
 724             else
 725             {
 726                 WORD *stack = get_stack( context );
 727                 context->Eip = *stack++;
 728                 context->SegCs  = *stack++;
 729                 SET_LOWORD(context->EFlags,*stack);
 730                 add_stack(context, 3*sizeof(WORD));  /* Pop the return address and flags */
 731             }
 732             return 0;
 733
 734         case 0xe4: /* inb al,XX */
 735             SET_LOBYTE(context->Eax,INSTR_inport( instr[1], 1, context ));
 736             context->Eip += prefixlen + 2;
 737             return 0;
 738
 739         case 0xe5: /* in (e)ax,XX */
 740             if (long_op)
 741                 context->Eax = INSTR_inport( instr[1], 4, context );
 742             else
 743                 SET_LOWORD(context->Eax, INSTR_inport( instr[1], 2, context ));
 744             context->Eip += prefixlen + 2;
 745             return 0;
 746
 747         case 0xe6: /* outb XX,al */
 748             INSTR_outport( instr[1], 1, LOBYTE(context->Eax), context );
 749             context->Eip += prefixlen + 2;
 750             return 0;
 751
 752         case 0xe7: /* out XX,(e)ax */
 753             if (long_op)
 754                 INSTR_outport( instr[1], 4, context->Eax, context );
 755             else
 756                 INSTR_outport( instr[1], 2, LOWORD(context->Eax), context );
 757             context->Eip += prefixlen + 2;
 758             return 0;
 759
 760         case 0xec: /* inb al,dx */
 761             SET_LOBYTE(context->Eax, INSTR_inport( LOWORD(context->Edx), 1, context ) );
 762             context->Eip += prefixlen + 1;
 763             return 0;
 764
 765         case 0xed: /* in (e)ax,dx */
 766             if (long_op)
 767                 context->Eax = INSTR_inport( LOWORD(context->Edx), 4, context );
 768             else
 769                 SET_LOWORD(context->Eax, INSTR_inport( LOWORD(context->Edx), 2, context ));
 770             context->Eip += prefixlen + 1;
 771             return 0;
 772
 773         case 0xee: /* outb dx,al */
 774             INSTR_outport( LOWORD(context->Edx), 1, LOBYTE(context->Eax), context );
 775             context->Eip += prefixlen + 1;
 776             return 0;
 777
 778         case 0xef: /* out dx,(e)ax */
 779             if (long_op)
 780                 INSTR_outport( LOWORD(context->Edx), 4, context->Eax, context );
 781             else
 782                 INSTR_outport( LOWORD(context->Edx), 2, LOWORD(context->Eax), context );
 783             context->Eip += prefixlen + 1;
 784             return 0;
 785
 786         case 0xfa: /* cli */
 787             NtCurrentTeb()->dpmi_vif = 0;
 788             context->Eip += prefixlen + 1;
 789             return 0;
 790
 791         case 0xfb: /* sti */
 792             NtCurrentTeb()->dpmi_vif = 1;
 793             context->Eip += prefixlen + 1;
 794             if (NtCurrentTeb()->vm86_pending)
 795             {
 796                 NtCurrentTeb()->vm86_pending = 0;
 797                 return EXCEPTION_VM86_STI;
 798             }
 799             return 0;
 800     }
 801     return ret;  /* Unable to emulate it */
 802 }
 803
 804 #endif  /* __i386__ */