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