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
  30 WINE_DEFAULT_DEBUG_CHANNEL(int);
  31 WINE_DECLARE_DEBUG_CHANNEL(io);
  32
  33 #ifdef __i386__
  34
  35 /* macros to set parts of a DWORD */
  36 #define SET_LOWORD(dw,val)  ((dw) = ((dw) & 0xffff0000) | LOWORD(val))
  37 #define SET_LOBYTE(dw,val)  ((dw) = ((dw) & 0xffffff00) | LOBYTE(val))
  38 #define ADD_LOWORD(dw,val)  ((dw) = ((dw) & 0xffff0000) | LOWORD((DWORD)(dw)+(val)))
  39
  40 inline static void add_stack( CONTEXT86 *context, int offset )
  41 {
  42     if (ISV86(context) || !IS_SELECTOR_32BIT(context->SegSs))
  43         ADD_LOWORD( context->Esp, offset );
  44     else
  45         context->Esp += offset;
  46 }
  47
  48 inline static void *make_ptr( CONTEXT86 *context, DWORD seg, DWORD off, int long_addr )
  49 {
  50     if (ISV86(context)) return PTR_REAL_TO_LIN( seg, off );
  51     if (IS_SELECTOR_SYSTEM(seg)) return (void *)off;
  52     if (!long_addr) off = LOWORD(off);
  53     return (char *) MapSL( MAKESEGPTR( seg, 0 ) ) + off;
  54 }
  55
  56 inline static void *get_stack( CONTEXT86 *context )
  57 {
  58     if (ISV86(context)) return PTR_REAL_TO_LIN( context->SegSs, context->Esp );
  59     return wine_ldt_get_ptr( context->SegSs, context->Esp );
  60 }
  61
  62 /***********************************************************************
  63  *           INSTR_ReplaceSelector
  64  *
  65  * Try to replace an invalid selector by a valid one.
  66  * The only selector where it is allowed to do "mov ax,40;mov es,ax"
  67  * is the so called 'bimodal' selector 0x40, which points to the BIOS
  68  * data segment. Used by (at least) Borland products (and programs compiled
  69  * using Borland products).
  70  *
  71  * See Undocumented Windows, Chapter 5, __0040.
  72  */
  73 static BOOL INSTR_ReplaceSelector( CONTEXT86 *context, WORD *sel )
  74 {
  75     extern char Call16_Start, Call16_End;
  76
  77     if (IS_SELECTOR_SYSTEM(context->SegCs))
  78         if (    (char *)context->Eip >= &Call16_Start
  79              && (char *)context->Eip <  &Call16_End   )
  80         {
  81             /* Saved selector may have become invalid when the relay code */
  82             /* tries to restore it. We simply clear it. */
  83             *sel = 0;
  84             return TRUE;
  85         }
  86
  87     if (*sel == 0x40)
  88     {
  89         static WORD sys_timer = 0;
  90         if (!sys_timer)
  91             sys_timer = CreateSystemTimer( 55, DOSMEM_Tick );
  92         *sel = DOSMEM_BiosDataSeg;
  93         return TRUE;
  94     }
  95     return FALSE;  /* Can't replace selector, crashdump */
  96 }
  97
  98
  99 /***********************************************************************
 100  *           INSTR_GetOperandAddr
 101  *
 102  * Return the address of an instruction operand (from the mod/rm byte).
 103  */
 104 static BYTE *INSTR_GetOperandAddr( CONTEXT86 *context, BYTE *instr,
 105                                    int long_addr, int segprefix, int *len )
 106 {
 107     int mod, rm, base, index = 0, ss = 0, seg = 0, off;
 108     LDT_ENTRY entry;
 109
 110 #define GET_VAL(val,type) \
 111     { *val = *(type *)instr; instr += sizeof(type); *len += sizeof(type); }
 112
 113     *len = 0;
 114     GET_VAL( &mod, BYTE );
 115     rm = mod & 7;
 116     mod >>= 6;
 117
 118     if (mod == 3)
 119     {
 120         switch(rm)
 121         {
 122         case 0: return (BYTE *)&context->Eax;
 123         case 1: return (BYTE *)&context->Ecx;
 124         case 2: return (BYTE *)&context->Edx;
 125         case 3: return (BYTE *)&context->Ebx;
 126         case 4: return (BYTE *)&context->Esp;
 127         case 5: return (BYTE *)&context->Ebp;
 128         case 6: return (BYTE *)&context->Esi;
 129         case 7: return (BYTE *)&context->Edi;
 130         }
 131     }
 132
 133     if (long_addr)
 134     {
 135         if (rm == 4)
 136         {
 137             BYTE sib;
 138             GET_VAL( &sib, BYTE );
 139             rm = sib & 7;
 140             ss = sib >> 6;
 141             switch(sib >> 3)
 142             {
 143             case 0: index = context->Eax; break;
 144             case 1: index = context->Ecx; break;
 145             case 2: index = context->Edx; break;
 146             case 3: index = context->Ebx; break;
 147             case 4: index = 0; break;
 148             case 5: index = context->Ebp; break;
 149             case 6: index = context->Esi; break;
 150             case 7: index = context->Edi; break;
 151             }
 152         }
 153
 154         switch(rm)
 155         {
 156         case 0: base = context->Eax; seg = context->SegDs; break;
 157         case 1: base = context->Ecx; seg = context->SegDs; break;
 158         case 2: base = context->Edx; seg = context->SegDs; break;
 159         case 3: base = context->Ebx; seg = context->SegDs; break;
 160         case 4: base = context->Esp; seg = context->SegSs; break;
 161         case 5: base = context->Ebp; seg = context->SegSs; break;
 162         case 6: base = context->Esi; seg = context->SegDs; break;
 163         case 7: base = context->Edi; seg = context->SegDs; break;
 164         }
 165         switch (mod)
 166         {
 167         case 0:
 168             if (rm == 5)  /* special case: ds:(disp32) */
 169             {
 170                 GET_VAL( &base, DWORD );
 171                 seg = context->SegDs;
 172             }
 173             break;
 174
 175         case 1:  /* 8-bit disp */
 176             GET_VAL( &off, BYTE );
 177             base += (signed char)off;
 178             break;
 179
 180         case 2:  /* 32-bit disp */
 181             GET_VAL( &off, DWORD );
 182             base += (signed long)off;
 183             break;
 184         }
 185     }
 186     else  /* short address */
 187     {
 188         switch(rm)
 189         {
 190         case 0:  /* ds:(bx,si) */
 191             base = LOWORD(context->Ebx) + LOWORD(context->Esi);
 192             seg  = context->SegDs;
 193             break;
 194         case 1:  /* ds:(bx,di) */
 195             base = LOWORD(context->Ebx) + LOWORD(context->Edi);
 196             seg  = context->SegDs;
 197             break;
 198         case 2:  /* ss:(bp,si) */
 199             base = LOWORD(context->Ebp) + LOWORD(context->Esi);
 200             seg  = context->SegSs;
 201             break;
 202         case 3:  /* ss:(bp,di) */
 203             base = LOWORD(context->Ebp) + LOWORD(context->Edi);
 204             seg  = context->SegSs;
 205             break;
 206         case 4:  /* ds:(si) */
 207             base = LOWORD(context->Esi);
 208             seg  = context->SegDs;
 209             break;
 210         case 5:  /* ds:(di) */
 211             base = LOWORD(context->Edi);
 212             seg  = context->SegDs;
 213             break;
 214         case 6:  /* ss:(bp) */
 215             base = LOWORD(context->Ebp);
 216             seg  = context->SegSs;
 217             break;
 218         case 7:  /* ds:(bx) */
 219             base = LOWORD(context->Ebx);
 220             seg  = context->SegDs;
 221             break;
 222         }
 223
 224         switch(mod)
 225         {
 226         case 0:
 227             if (rm == 6)  /* special case: ds:(disp16) */
 228             {
 229                 GET_VAL( &base, WORD );
 230                 seg  = context->SegDs;
 231             }
 232             break;
 233
 234         case 1:  /* 8-bit disp */
 235             GET_VAL( &off, BYTE );
 236             base += (signed char)off;
 237             break;
 238
 239         case 2:  /* 16-bit disp */
 240             GET_VAL( &off, WORD );
 241             base += (signed short)off;
 242             break;
 243         }
 244         base &= 0xffff;
 245     }
 246     if (segprefix != -1) seg = segprefix;
 247
 248     /* Make sure the segment and offset are valid */
 249     if (IS_SELECTOR_SYSTEM(seg)) return (BYTE *)(base + (index << ss));
 250     if ((seg & 7) != 7) return NULL;
 251     wine_ldt_get_entry( seg, &entry );
 252     if (wine_ldt_is_empty( &entry )) return NULL;
 253     if (wine_ldt_get_limit(&entry) < (base + (index << ss))) return NULL;
 254     return (char *)wine_ldt_get_base(&entry) + base + (index << ss);
 255 #undef GET_VAL
 256 }
 257
 258
 259 /***********************************************************************
 260  *           INSTR_EmulateLDS
 261  *
 262  * Emulate the LDS (and LES,LFS,etc.) instruction.
 263  */
 264 static BOOL INSTR_EmulateLDS( CONTEXT86 *context, BYTE *instr, int long_op,
 265                               int long_addr, int segprefix, int *len )
 266 {
 267     WORD seg;
 268     BYTE *regmodrm = instr + 1 + (*instr == 0x0f);
 269     BYTE *addr = INSTR_GetOperandAddr( context, regmodrm,
 270                                        long_addr, segprefix, len );
 271     if (!addr)
 272         return FALSE;  /* Unable to emulate it */
 273     seg = *(WORD *)(addr + (long_op ? 4 : 2));
 274
 275     if (!INSTR_ReplaceSelector( context, &seg ))
 276         return FALSE;  /* Unable to emulate it */
 277
 278     /* Now store the offset in the correct register */
 279
 280     switch((*regmodrm >> 3) & 7)
 281     {
 282     case 0:
 283         if (long_op) context->Eax = *(DWORD *)addr;
 284         else SET_LOWORD(context->Eax,*(WORD *)addr);
 285         break;
 286     case 1:
 287         if (long_op) context->Ecx = *(DWORD *)addr;
 288         else SET_LOWORD(context->Ecx,*(WORD *)addr);
 289         break;
 290     case 2:
 291         if (long_op) context->Edx = *(DWORD *)addr;
 292         else SET_LOWORD(context->Edx,*(WORD *)addr);
 293         break;
 294     case 3:
 295         if (long_op) context->Ebx = *(DWORD *)addr;
 296         else SET_LOWORD(context->Ebx,*(WORD *)addr);
 297         break;
 298     case 4:
 299         if (long_op) context->Esp = *(DWORD *)addr;
 300         else SET_LOWORD(context->Esp,*(WORD *)addr);
 301         break;
 302     case 5:
 303         if (long_op) context->Ebp = *(DWORD *)addr;
 304         else SET_LOWORD(context->Ebp,*(WORD *)addr);
 305         break;
 306     case 6:
 307         if (long_op) context->Esi = *(DWORD *)addr;
 308         else SET_LOWORD(context->Esi,*(WORD *)addr);
 309         break;
 310     case 7:
 311         if (long_op) context->Edi = *(DWORD *)addr;
 312         else SET_LOWORD(context->Edi,*(WORD *)addr);
 313         break;
 314     }
 315
 316     /* Store the correct segment in the segment register */
 317
 318     switch(*instr)
 319     {
 320     case 0xc4: context->SegEs = seg; break;  /* les */
 321     case 0xc5: context->SegDs = seg; break;  /* lds */
 322     case 0x0f: switch(instr[1])
 323                {
 324                case 0xb2: context->SegSs = seg; break;  /* lss */
 325                case 0xb4: context->SegFs = seg; break;  /* lfs */
 326                case 0xb5: context->SegGs = seg; break;  /* lgs */
 327                }
 328                break;
 329     }
 330
 331     /* Add the opcode size to the total length */
 332
 333     *len += 1 + (*instr == 0x0f);
 334     return TRUE;
 335 }
 336
 337 /***********************************************************************
 338  *           INSTR_inport
 339  *
 340  * input on a I/O port
 341  */
 342 static DWORD INSTR_inport( WORD port, int size, CONTEXT86 *context )
 343 {
 344     DWORD res = IO_inport( port, size );
 345     if (TRACE_ON(io))
 346     {
 347         switch(size)
 348         {
 349         case 1:
 350             DPRINTF( "0x%x < %02x @ %04x:%04x\n", port, LOBYTE(res),
 351                      (WORD)context->SegCs, LOWORD(context->Eip));
 352             break;
 353         case 2:
 354             DPRINTF( "0x%x < %04x @ %04x:%04x\n", port, LOWORD(res),
 355                      (WORD)context->SegCs, LOWORD(context->Eip));
 356             break;
 357         case 4:
 358             DPRINTF( "0x%x < %08lx @ %04x:%04x\n", port, res,
 359                      (WORD)context->SegCs, LOWORD(context->Eip));
 360             break;
 361         }
 362     }
 363     return res;
 364 }
 365
 366
 367 /***********************************************************************
 368  *           INSTR_outport
 369  *
 370  * output on a I/O port
 371  */
 372 static void INSTR_outport( WORD port, int size, DWORD val, CONTEXT86 *context )
 373 {
 374     IO_outport( port, size, val );
 375     if (TRACE_ON(io))
 376     {
 377         switch(size)
 378         {
 379         case 1:
 380             DPRINTF("0x%x > %02x @ %04x:%04x\n", port, LOBYTE(val),
 381                     (WORD)context->SegCs, LOWORD(context->Eip));
 382             break;
 383         case 2:
 384             DPRINTF("0x%x > %04x @ %04x:%04x\n", port, LOWORD(val),
 385                     (WORD)context->SegCs, LOWORD(context->Eip));
 386             break;
 387         case 4:
 388             DPRINTF("0x%x > %08lx @ %04x:%04x\n", port, val,
 389                     (WORD)context->SegCs, LOWORD(context->Eip));
 390             break;
 391         }
 392     }
 393 }
 394
 395
 396 /***********************************************************************
 397  *           INSTR_EmulateInstruction
 398  *
 399  * Emulate a privileged instruction. Returns TRUE if emulation successful.
 400  */
 401 BOOL INSTR_EmulateInstruction( CONTEXT86 *context )
 402 {
 403     int prefix, segprefix, prefixlen, len, repX, long_op, long_addr;
 404     SEGPTR gpHandler;
 405     BYTE *instr;
 406
 407     long_op = long_addr = (!ISV86(context) && IS_SELECTOR_32BIT(context->SegCs));
 408     instr = make_ptr( context, context->SegCs, context->Eip, TRUE );
 409     if (!instr) return FALSE;
 410
 411     /* First handle any possible prefix */
 412
 413     segprefix = -1;  /* no prefix */
 414     prefix = 1;
 415     repX = 0;
 416     prefixlen = 0;
 417     while(prefix)
 418     {
 419         switch(*instr)
 420         {
 421         case 0x2e:
 422             segprefix = context->SegCs;
 423             break;
 424         case 0x36:
 425             segprefix = context->SegSs;
 426             break;
 427         case 0x3e:
 428             segprefix = context->SegDs;
 429             break;
 430         case 0x26:
 431             segprefix = context->SegEs;
 432             break;
 433         case 0x64:
 434             segprefix = context->SegFs;
 435             break;
 436         case 0x65:
 437             segprefix = context->SegGs;
 438             break;
 439         case 0x66:
 440             long_op = !long_op;  /* opcode size prefix */
 441             break;
 442         case 0x67:
 443             long_addr = !long_addr;  /* addr size prefix */
 444             break;
 445         case 0xf0:  /* lock */
 446             break;
 447         case 0xf2:  /* repne */
 448             repX = 1;
 449             break;
 450         case 0xf3:  /* repe */
 451             repX = 2;
 452             break;
 453         default:
 454             prefix = 0;  /* no more prefixes */
 455             break;
 456         }
 457         if (prefix)
 458         {
 459             instr++;
 460             prefixlen++;
 461         }
 462     }
 463
 464     /* Now look at the actual instruction */
 465
 466     switch(*instr)
 467     {
 468         case 0x07: /* pop es */
 469         case 0x17: /* pop ss */
 470         case 0x1f: /* pop ds */
 471             {
 472                 WORD seg = *(WORD *)get_stack( context );
 473                 if (INSTR_ReplaceSelector( context, &seg ))
 474                 {
 475                     switch(*instr)
 476                     {
 477                     case 0x07: context->SegEs = seg; break;
 478                     case 0x17: context->SegSs = seg; break;
 479                     case 0x1f: context->SegDs = seg; break;
 480                     }
 481                     add_stack(context, long_op ? 4 : 2);
 482                     context->Eip += prefixlen + 1;
 483                     return TRUE;
 484                 }
 485             }
 486             break;  /* Unable to emulate it */
 487
 488         case 0x0f: /* extended instruction */
 489             switch(instr[1])
 490             {
 491             case 0x22: /* mov eax, crX */
 492                 switch (instr[2]) {
 493                 case 0xc0:
 494                         ERR("mov eax,cr0 at 0x%08lx, EAX=0x%08lx\n",
 495                             context->Eip,context->Eax );
 496                         context->Eip += prefixlen+3;
 497                         return TRUE;
 498                 default:
 499                         break; /*fallthrough to bad instruction handling */
 500                 }
 501                 break; /*fallthrough to bad instruction handling */
 502             case 0x20: /* mov crX, eax */
 503                 switch (instr[2]) {
 504                 case 0xe0: /* mov cr4, eax */
 505                     /* CR4 register . See linux/arch/i386/mm/init.c, X86_CR4_ defs
 506                      * bit 0: VME       Virtual Mode Exception ?
 507                      * bit 1: PVI       Protected mode Virtual Interrupt
 508                      * bit 2: TSD       Timestamp disable
 509                      * bit 3: DE        Debugging extensions
 510                      * bit 4: PSE       Page size extensions
 511                      * bit 5: PAE   Physical address extension
 512                      * bit 6: MCE       Machine check enable
 513                      * bit 7: PGE   Enable global pages
 514                      * bit 8: PCE       Enable performance counters at IPL3
 515                      */
 516                     ERR("mov cr4,eax at 0x%08lx\n",context->Eip);
 517                     context->Eax = 0;
 518                     context->Eip += prefixlen+3;
 519                     return TRUE;
 520                 case 0xc0: /* mov cr0, eax */
 521                     ERR("mov cr0,eax at 0x%08lx\n",context->Eip);
 522                     context->Eax = 0x10; /* FIXME: set more bits ? */
 523                     context->Eip += prefixlen+3;
 524                     return TRUE;
 525                 default: /* fallthrough to illegal instruction */
 526                     break;
 527                 }
 528                 /* fallthrough to illegal instruction */
 529                 break;
 530             case 0xa1: /* pop fs */
 531                 {
 532                     WORD seg = *(WORD *)get_stack( context );
 533                     if (INSTR_ReplaceSelector( context, &seg ))
 534                     {
 535                         context->SegFs = seg;
 536                         add_stack(context, long_op ? 4 : 2);
 537                         context->Eip += prefixlen + 2;
 538                         return TRUE;
 539                     }
 540                 }
 541                 break;
 542             case 0xa9: /* pop gs */
 543                 {
 544                     WORD seg = *(WORD *)get_stack( context );
 545                     if (INSTR_ReplaceSelector( context, &seg ))
 546                     {
 547                         context->SegGs = seg;
 548                         add_stack(context, long_op ? 4 : 2);
 549                         context->Eip += prefixlen + 2;
 550                         return TRUE;
 551                     }
 552                 }
 553                 break;
 554             case 0xb2: /* lss addr,reg */
 555             case 0xb4: /* lfs addr,reg */
 556             case 0xb5: /* lgs addr,reg */
 557                 if (INSTR_EmulateLDS( context, instr, long_op,
 558                                       long_addr, segprefix, &len ))
 559                 {
 560                     context->Eip += prefixlen + len;
 561                     return TRUE;
 562                 }
 563                 break;
 564             }
 565             break;  /* Unable to emulate it */
 566
 567         case 0x6c: /* insb     */
 568         case 0x6d: /* insw/d   */
 569         case 0x6e: /* outsb    */
 570         case 0x6f: /* outsw/d  */
 571             {
 572               int typ = *instr;  /* Just in case it's overwritten.  */
 573               int outp = (typ >= 0x6e);
 574               unsigned long count = repX ?
 575                           (long_addr ? context->Ecx : LOWORD(context->Ecx)) : 1;
 576               int opsize = (typ & 1) ? (long_op ? 4 : 2) : 1;
 577               int step = (context->EFlags & 0x400) ? -opsize : +opsize;
 578               int seg = outp ? context->SegDs : context->SegEs;  /* FIXME: is this right? */
 579
 580               if (outp)
 581                 /* FIXME: Check segment readable.  */
 582                 (void)0;
 583               else
 584                 /* FIXME: Check segment writeable.  */
 585                 (void)0;
 586
 587               if (repX)
 588               {
 589                 if (long_addr) context->Ecx = 0;
 590                 else SET_LOWORD(context->Ecx,0);
 591               }
 592
 593               while (count-- > 0)
 594                 {
 595                   void *data;
 596                   WORD dx = LOWORD(context->Edx);
 597                   if (outp)
 598                   {
 599                       data = make_ptr( context, seg, context->Esi, long_addr );
 600                       if (long_addr) context->Esi += step;
 601                       else ADD_LOWORD(context->Esi,step);
 602                   }
 603                   else
 604                   {
 605                       data = make_ptr( context, seg, context->Edi, long_addr );
 606                       if (long_addr) context->Edi += step;
 607                       else ADD_LOWORD(context->Edi,step);
 608                   }
 609
 610                   switch (typ)
 611                   {
 612                     case 0x6c:
 613                       *(BYTE *)data = INSTR_inport( dx, 1, context );
 614                       break;
 615                     case 0x6d:
 616                       if (long_op)
 617                           *(DWORD *)data = INSTR_inport( dx, 4, context );
 618                       else
 619                           *(WORD *)data = INSTR_inport( dx, 2, context );
 620                       break;
 621                     case 0x6e:
 622                         INSTR_outport( dx, 1, *(BYTE *)data, context );
 623                         break;
 624                     case 0x6f:
 625                         if (long_op)
 626                             INSTR_outport( dx, 4, *(DWORD *)data, context );
 627                         else
 628                             INSTR_outport( dx, 2, *(WORD *)data, context );
 629                         break;
 630                     }
 631                 }
 632               context->Eip += prefixlen + 1;
 633             }
 634             return TRUE;
 635
 636         case 0x8e: /* mov XX,segment_reg */
 637             {
 638                 WORD seg;
 639                 BYTE *addr = INSTR_GetOperandAddr(context, instr + 1,
 640                                                   long_addr, segprefix, &len );
 641                 if (!addr)
 642                     break;  /* Unable to emulate it */
 643                 seg = *(WORD *)addr;
 644                 if (!INSTR_ReplaceSelector( context, &seg ))
 645                     break;  /* Unable to emulate it */
 646
 647                 switch((instr[1] >> 3) & 7)
 648                 {
 649                 case 0:
 650                     context->SegEs = seg;
 651                     context->Eip += prefixlen + len + 1;
 652                     return TRUE;
 653                 case 1:  /* cs */
 654                     break;
 655                 case 2:
 656                     context->SegSs = seg;
 657                     context->Eip += prefixlen + len + 1;
 658                     return TRUE;
 659                 case 3:
 660                     context->SegDs = seg;
 661                     context->Eip += prefixlen + len + 1;
 662                     return TRUE;
 663                 case 4:
 664                     context->SegFs = seg;
 665                     context->Eip += prefixlen + len + 1;
 666                     return TRUE;
 667                 case 5:
 668                     context->SegGs = seg;
 669                     context->Eip += prefixlen + len + 1;
 670                     return TRUE;
 671                 case 6:  /* unused */
 672                 case 7:  /* unused */
 673                     break;
 674                 }
 675             }
 676             break;  /* Unable to emulate it */
 677
 678         case 0xc4: /* les addr,reg */
 679         case 0xc5: /* lds addr,reg */
 680             if (INSTR_EmulateLDS( context, instr, long_op,
 681                                   long_addr, segprefix, &len ))
 682             {
 683                 context->Eip += prefixlen + len;
 684                 return TRUE;
 685             }
 686             break;  /* Unable to emulate it */
 687
 688         case 0xcd: /* int <XX> */
 689            if(!Dosvm.EmulateInterruptPM && !DPMI_LoadDosSystem())
 690                ERR("could not initialize interrupt handling\n");
 691            else {
 692                context->Eip += prefixlen + 2;
 693                Dosvm.EmulateInterruptPM( context, instr[1] );
 694                return TRUE;
 695            }
 696            break;  /* Unable to emulate it */
 697
 698         case 0xcf: /* iret */
 699             if (long_op)
 700             {
 701                 DWORD *stack = get_stack( context );
 702                 context->Eip = *stack++;
 703                 context->SegCs  = *stack++;
 704                 context->EFlags = *stack;
 705                 add_stack(context, 3*sizeof(DWORD));  /* Pop the return address and flags */
 706             }
 707             else
 708             {
 709                 WORD *stack = get_stack( context );
 710                 context->Eip = *stack++;
 711                 context->SegCs  = *stack++;
 712                 SET_LOWORD(context->EFlags,*stack);
 713                 add_stack(context, 3*sizeof(WORD));  /* Pop the return address and flags */
 714             }
 715             return TRUE;
 716
 717         case 0xe4: /* inb al,XX */
 718             SET_LOBYTE(context->Eax,INSTR_inport( instr[1], 1, context ));
 719             context->Eip += prefixlen + 2;
 720             return TRUE;
 721
 722         case 0xe5: /* in (e)ax,XX */
 723             if (long_op)
 724                 context->Eax = INSTR_inport( instr[1], 4, context );
 725             else
 726                 SET_LOWORD(context->Eax, INSTR_inport( instr[1], 2, context ));
 727             context->Eip += prefixlen + 2;
 728             return TRUE;
 729
 730         case 0xe6: /* outb XX,al */
 731             INSTR_outport( instr[1], 1, LOBYTE(context->Eax), context );
 732             context->Eip += prefixlen + 2;
 733             return TRUE;
 734
 735         case 0xe7: /* out XX,(e)ax */
 736             if (long_op)
 737                 INSTR_outport( instr[1], 4, context->Eax, context );
 738             else
 739                 INSTR_outport( instr[1], 2, LOWORD(context->Eax), context );
 740             context->Eip += prefixlen + 2;
 741             return TRUE;
 742
 743         case 0xec: /* inb al,dx */
 744             SET_LOBYTE(context->Eax, INSTR_inport( LOWORD(context->Edx), 1, context ) );
 745             context->Eip += prefixlen + 1;
 746             return TRUE;
 747
 748         case 0xed: /* in (e)ax,dx */
 749             if (long_op)
 750                 context->Eax = INSTR_inport( LOWORD(context->Edx), 4, context );
 751             else
 752                 SET_LOWORD(context->Eax, INSTR_inport( LOWORD(context->Edx), 2, context ));
 753             context->Eip += prefixlen + 1;
 754             return TRUE;
 755
 756         case 0xee: /* outb dx,al */
 757             INSTR_outport( LOWORD(context->Edx), 1, LOBYTE(context->Eax), context );
 758             context->Eip += prefixlen + 1;
 759             return TRUE;
 760
 761         case 0xef: /* out dx,(e)ax */
 762             if (long_op)
 763                 INSTR_outport( LOWORD(context->Edx), 4, context->Eax, context );
 764             else
 765                 INSTR_outport( LOWORD(context->Edx), 2, LOWORD(context->Eax), context );
 766             context->Eip += prefixlen + 1;
 767             return TRUE;
 768
 769         case 0xfa: /* cli, ignored */
 770             context->Eip += prefixlen + 1;
 771             return TRUE;
 772
 773         case 0xfb: /* sti, ignored */
 774             context->Eip += prefixlen + 1;
 775             return TRUE;
 776     }
 777
 778
 779     /* Check for Win16 __GP handler */
 780     gpHandler = HasGPHandler16( MAKESEGPTR( context->SegCs, context->Eip ) );
 781     if (gpHandler)
 782     {
 783         WORD *stack = get_stack( context );
 784         *--stack = context->SegCs;
 785         *--stack = context->Eip;
 786         add_stack(context, -2*sizeof(WORD));
 787
 788         context->SegCs = SELECTOROF( gpHandler );
 789         context->Eip   = OFFSETOF( gpHandler );
 790         return TRUE;
 791     }
 792     return FALSE;  /* Unable to emulate it */
 793 }
 794
 795 #endif  /* __i386__ */