dlls/kernel32/instr.c

   1 /*
   2  * Emulation of privileged instructions
   3  *
   4  * Copyright 1995 Alexandre Julliard
   5  * Copyright 2005 Ivan Leo Puoti
   6  * Copyright 2005 Laurent Pinchart
   7  *
   8  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; either
  11  * version 2.1 of the License, or (at your option) any later version.
  12  *
  13  * This library is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  21  */
  22
  23 #include "config.h"
  24 #include "wine/port.h"
  25
  26 #ifdef __i386__
  27
  28 #include <stdarg.h>
  29
  30 #include "windef.h"
  31 #include "winbase.h"
  32 #include "winternl.h"
  33 #include "wine/winuser16.h"
  34 #include "excpt.h"
  35 #include "wine/debug.h"
  36 #include "kernel_private.h"
  37 #include "kernel16_private.h"
  38 #include "wine/exception.h"
  39
  40 WINE_DEFAULT_DEBUG_CHANNEL(int);
  41 WINE_DECLARE_DEBUG_CHANNEL(io);
  42
  43 /* macros to set parts of a DWORD */
  44 #define SET_LOWORD(dw,val)  ((dw) = ((dw) & 0xffff0000) | LOWORD(val))
  45 #define SET_LOBYTE(dw,val)  ((dw) = ((dw) & 0xffffff00) | LOBYTE(val))
  46 #define ADD_LOWORD(dw,val)  ((dw) = ((dw) & 0xffff0000) | LOWORD((DWORD)(dw)+(val)))
  47 #define ISV86(context)      ((context)->EFlags & 0x00020000)
  48
  49 static inline void add_stack( CONTEXT86 *context, int offset )
  50 {
  51     if (ISV86(context) || !IS_SELECTOR_32BIT(context->SegSs))
  52         ADD_LOWORD( context->Esp, offset );
  53     else
  54         context->Esp += offset;
  55 }
  56
  57 static inline void *make_ptr( CONTEXT86 *context, DWORD seg, DWORD off, int long_addr )
  58 {
  59     if (ISV86(context)) return (void *)((seg << 4) + LOWORD(off));
  60     if (wine_ldt_is_system(seg)) return (void *)off;
  61     if (!long_addr) off = LOWORD(off);
  62     return (char *) MapSL( MAKESEGPTR( seg, 0 ) ) + off;
  63 }
  64
  65 static inline void *get_stack( CONTEXT86 *context )
  66 {
  67     if (ISV86(context)) return (void *)((context->SegSs << 4) + LOWORD(context->Esp));
  68     return wine_ldt_get_ptr( context->SegSs, context->Esp );
  69 }
  70
  71 #include "pshpack1.h"
  72 struct idtr
  73 {
  74     WORD  limit;
  75     BYTE *base;
  76 };
  77 #include "poppack.h"
  78
  79 static LDT_ENTRY idt[256];
  80
  81 static inline struct idtr get_idtr(void)
  82 {
  83     struct idtr ret;
  84 #if defined(__i386__) && defined(__GNUC__)
  85     __asm__( "sidtl %0" : "=m" (ret) );
  86 #else
  87     ret.base = (BYTE *)idt;
  88     ret.limit = sizeof(idt) - 1;
  89 #endif
  90     return ret;
  91 }
  92
  93
  94 /***********************************************************************
  95  *           INSTR_ReplaceSelector
  96  *
  97  * Try to replace an invalid selector by a valid one.
  98  * The only selector where it is allowed to do "mov ax,40;mov es,ax"
  99  * is the so called 'bimodal' selector 0x40, which points to the BIOS
 100  * data segment. Used by (at least) Borland products (and programs compiled
 101  * using Borland products).
 102  *
 103  * See Undocumented Windows, Chapter 5, __0040.
 104  */
 105 static BOOL INSTR_ReplaceSelector( CONTEXT86 *context, WORD *sel )
 106 {
 107     if (*sel == 0x40)
 108     {
 109         static WORD sys_timer = 0;
 110         if (!sys_timer)
 111         {
 112             if (!winedos.BiosTick) load_winedos();
 113             if (winedos.BiosTick)
 114                 sys_timer = CreateSystemTimer( 55, winedos.BiosTick );
 115         }
 116         *sel = DOSMEM_BiosDataSeg;
 117         return TRUE;
 118     }
 119     return FALSE;  /* Can't replace selector, crashdump */
 120 }
 121
 122
 123 /* store an operand into a register */
 124 static void store_reg( CONTEXT86 *context, BYTE regmodrm, const BYTE *addr, int long_op )
 125 {
 126     switch((regmodrm >> 3) & 7)
 127     {
 128     case 0:
 129         if (long_op) context->Eax = *(const DWORD *)addr;
 130         else SET_LOWORD(context->Eax, *(const WORD *)addr);
 131         break;
 132     case 1:
 133         if (long_op) context->Ecx = *(const DWORD *)addr;
 134         else SET_LOWORD(context->Ecx, *(const WORD *)addr);
 135         break;
 136     case 2:
 137         if (long_op) context->Edx = *(const DWORD *)addr;
 138         else SET_LOWORD(context->Edx, *(const WORD *)addr);
 139         break;
 140     case 3:
 141         if (long_op) context->Ebx = *(const DWORD *)addr;
 142         else SET_LOWORD(context->Ebx, *(const WORD *)addr);
 143         break;
 144     case 4:
 145         if (long_op) context->Esp = *(const DWORD *)addr;
 146         else SET_LOWORD(context->Esp, *(const WORD *)addr);
 147         break;
 148     case 5:
 149         if (long_op) context->Ebp = *(const DWORD *)addr;
 150         else SET_LOWORD(context->Ebp, *(const WORD *)addr);
 151         break;
 152     case 6:
 153         if (long_op) context->Esi = *(const DWORD *)addr;
 154         else SET_LOWORD(context->Esi, *(const WORD *)addr);
 155         break;
 156     case 7:
 157         if (long_op) context->Edi = *(const DWORD *)addr;
 158         else SET_LOWORD(context->Edi, *(const WORD *)addr);
 159         break;
 160     }
 161 }
 162
 163 /***********************************************************************
 164  *           INSTR_GetOperandAddr
 165  *
 166  * Return the address of an instruction operand (from the mod/rm byte).
 167  */
 168 static BYTE *INSTR_GetOperandAddr( CONTEXT86 *context, BYTE *instr,
 169                                    int long_addr, int segprefix, int *len )
 170 {
 171     int mod, rm, base = 0, index = 0, ss = 0, seg = 0, off;
 172     LDT_ENTRY entry;
 173
 174 #define GET_VAL(val,type) \
 175     { *val = *(type *)instr; instr += sizeof(type); *len += sizeof(type); }
 176
 177     *len = 0;
 178     GET_VAL( &mod, BYTE );
 179     rm = mod & 7;
 180     mod >>= 6;
 181
 182     if (mod == 3)
 183     {
 184         switch(rm)
 185         {
 186         case 0: return (BYTE *)&context->Eax;
 187         case 1: return (BYTE *)&context->Ecx;
 188         case 2: return (BYTE *)&context->Edx;
 189         case 3: return (BYTE *)&context->Ebx;
 190         case 4: return (BYTE *)&context->Esp;
 191         case 5: return (BYTE *)&context->Ebp;
 192         case 6: return (BYTE *)&context->Esi;
 193         case 7: return (BYTE *)&context->Edi;
 194         }
 195     }
 196
 197     if (long_addr)
 198     {
 199         if (rm == 4)
 200         {
 201             BYTE sib;
 202             GET_VAL( &sib, BYTE );
 203             rm = sib & 7;
 204             ss = sib >> 6;
 205             switch(sib >> 3)
 206             {
 207             case 0: index = context->Eax; break;
 208             case 1: index = context->Ecx; break;
 209             case 2: index = context->Edx; break;
 210             case 3: index = context->Ebx; break;
 211             case 4: index = 0; break;
 212             case 5: index = context->Ebp; break;
 213             case 6: index = context->Esi; break;
 214             case 7: index = context->Edi; break;
 215             }
 216         }
 217
 218         switch(rm)
 219         {
 220         case 0: base = context->Eax; seg = context->SegDs; break;
 221         case 1: base = context->Ecx; seg = context->SegDs; break;
 222         case 2: base = context->Edx; seg = context->SegDs; break;
 223         case 3: base = context->Ebx; seg = context->SegDs; break;
 224         case 4: base = context->Esp; seg = context->SegSs; break;
 225         case 5: base = context->Ebp; seg = context->SegSs; break;
 226         case 6: base = context->Esi; seg = context->SegDs; break;
 227         case 7: base = context->Edi; seg = context->SegDs; break;
 228         }
 229         switch (mod)
 230         {
 231         case 0:
 232             if (rm == 5)  /* special case: ds:(disp32) */
 233             {
 234                 GET_VAL( &base, DWORD );
 235                 seg = context->SegDs;
 236             }
 237             break;
 238
 239         case 1:  /* 8-bit disp */
 240             GET_VAL( &off, BYTE );
 241             base += (signed char)off;
 242             break;
 243
 244         case 2:  /* 32-bit disp */
 245             GET_VAL( &off, DWORD );
 246             base += (signed long)off;
 247             break;
 248         }
 249     }
 250     else  /* short address */
 251     {
 252         switch(rm)
 253         {
 254         case 0:  /* ds:(bx,si) */
 255             base = LOWORD(context->Ebx) + LOWORD(context->Esi);
 256             seg  = context->SegDs;
 257             break;
 258         case 1:  /* ds:(bx,di) */
 259             base = LOWORD(context->Ebx) + LOWORD(context->Edi);
 260             seg  = context->SegDs;
 261             break;
 262         case 2:  /* ss:(bp,si) */
 263             base = LOWORD(context->Ebp) + LOWORD(context->Esi);
 264             seg  = context->SegSs;
 265             break;
 266         case 3:  /* ss:(bp,di) */
 267             base = LOWORD(context->Ebp) + LOWORD(context->Edi);
 268             seg  = context->SegSs;
 269             break;
 270         case 4:  /* ds:(si) */
 271             base = LOWORD(context->Esi);
 272             seg  = context->SegDs;
 273             break;
 274         case 5:  /* ds:(di) */
 275             base = LOWORD(context->Edi);
 276             seg  = context->SegDs;
 277             break;
 278         case 6:  /* ss:(bp) */
 279             base = LOWORD(context->Ebp);
 280             seg  = context->SegSs;
 281             break;
 282         case 7:  /* ds:(bx) */
 283             base = LOWORD(context->Ebx);
 284             seg  = context->SegDs;
 285             break;
 286         }
 287
 288         switch(mod)
 289         {
 290         case 0:
 291             if (rm == 6)  /* special case: ds:(disp16) */
 292             {
 293                 GET_VAL( &base, WORD );
 294                 seg  = context->SegDs;
 295             }
 296             break;
 297
 298         case 1:  /* 8-bit disp */
 299             GET_VAL( &off, BYTE );
 300             base += (signed char)off;
 301             break;
 302
 303         case 2:  /* 16-bit disp */
 304             GET_VAL( &off, WORD );
 305             base += (signed short)off;
 306             break;
 307         }
 308         base &= 0xffff;
 309     }
 310     if (segprefix != -1) seg = segprefix;
 311
 312     /* Make sure the segment and offset are valid */
 313     if (wine_ldt_is_system(seg)) return (BYTE *)(base + (index << ss));
 314     if ((seg & 7) != 7) return NULL;
 315     wine_ldt_get_entry( seg, &entry );
 316     if (wine_ldt_is_empty( &entry )) return NULL;
 317     if (wine_ldt_get_limit(&entry) < (base + (index << ss))) return NULL;
 318     return (BYTE *)wine_ldt_get_base(&entry) + base + (index << ss);
 319 #undef GET_VAL
 320 }
 321
 322
 323 /***********************************************************************
 324  *           INSTR_EmulateLDS
 325  *
 326  * Emulate the LDS (and LES,LFS,etc.) instruction.
 327  */
 328 static BOOL INSTR_EmulateLDS( CONTEXT86 *context, BYTE *instr, int long_op,
 329                               int long_addr, int segprefix, int *len )
 330 {
 331     WORD seg;
 332     BYTE *regmodrm = instr + 1 + (*instr == 0x0f);
 333     BYTE *addr = INSTR_GetOperandAddr( context, regmodrm,
 334                                        long_addr, segprefix, len );
 335     if (!addr)
 336         return FALSE;  /* Unable to emulate it */
 337     seg = *(WORD *)(addr + (long_op ? 4 : 2));
 338
 339     if (!INSTR_ReplaceSelector( context, &seg ))
 340         return FALSE;  /* Unable to emulate it */
 341
 342     /* Now store the offset in the correct register */
 343
 344     store_reg( context, *regmodrm, addr, long_op );
 345
 346     /* Store the correct segment in the segment register */
 347
 348     switch(*instr)
 349     {
 350     case 0xc4: context->SegEs = seg; break;  /* les */
 351     case 0xc5: context->SegDs = seg; break;  /* lds */
 352     case 0x0f: switch(instr[1])
 353                {
 354                case 0xb2: context->SegSs = seg; break;  /* lss */
 355                case 0xb4: context->SegFs = seg; break;  /* lfs */
 356                case 0xb5: context->SegGs = seg; break;  /* lgs */
 357                }
 358                break;
 359     }
 360
 361     /* Add the opcode size to the total length */
 362
 363     *len += 1 + (*instr == 0x0f);
 364     return TRUE;
 365 }
 366
 367 /***********************************************************************
 368  *           INSTR_inport
 369  *
 370  * input on an I/O port
 371  */
 372 static DWORD INSTR_inport( WORD port, int size, CONTEXT86 *context )
 373 {
 374     DWORD res = ~0U;
 375
 376     if (!winedos.inport) load_winedos();
 377     if (winedos.inport) res = winedos.inport( port, size );
 378
 379     if (TRACE_ON(io))
 380     {
 381         switch(size)
 382         {
 383         case 1:
 384             TRACE_(io)( "0x%x < %02x @ %04x:%04x\n", port, LOBYTE(res),
 385                      (WORD)context->SegCs, LOWORD(context->Eip));
 386             break;
 387         case 2:
 388             TRACE_(io)( "0x%x < %04x @ %04x:%04x\n", port, LOWORD(res),
 389                      (WORD)context->SegCs, LOWORD(context->Eip));
 390             break;
 391         case 4:
 392             TRACE_(io)( "0x%x < %08x @ %04x:%04x\n", port, res,
 393                      (WORD)context->SegCs, LOWORD(context->Eip));
 394             break;
 395         }
 396     }
 397     return res;
 398 }
 399
 400
 401 /***********************************************************************
 402  *           INSTR_outport
 403  *
 404  * output on an I/O port
 405  */
 406 static void INSTR_outport( WORD port, int size, DWORD val, CONTEXT86 *context )
 407 {
 408     if (!winedos.outport) load_winedos();
 409     if (winedos.outport) winedos.outport( port, size, val );
 410
 411     if (TRACE_ON(io))
 412     {
 413         switch(size)
 414         {
 415         case 1:
 416             TRACE_(io)("0x%x > %02x @ %04x:%04x\n", port, LOBYTE(val),
 417                     (WORD)context->SegCs, LOWORD(context->Eip));
 418             break;
 419         case 2:
 420             TRACE_(io)("0x%x > %04x @ %04x:%04x\n", port, LOWORD(val),
 421                     (WORD)context->SegCs, LOWORD(context->Eip));
 422             break;
 423         case 4:
 424             TRACE_(io)("0x%x > %08x @ %04x:%04x\n", port, val,
 425                     (WORD)context->SegCs, LOWORD(context->Eip));
 426             break;
 427         }
 428     }
 429 }
 430
 431
 432 /***********************************************************************
 433  *           __wine_emulate_instruction
 434  *
 435  * Emulate a privileged instruction.
 436  * Returns exception continuation status.
 437  */
 438 DWORD __wine_emulate_instruction( EXCEPTION_RECORD *rec, CONTEXT86 *context )
 439 {
 440     int prefix, segprefix, prefixlen, len, repX, long_op, long_addr;
 441     BYTE *instr;
 442
 443     long_op = long_addr = (!ISV86(context) && IS_SELECTOR_32BIT(context->SegCs));
 444     instr = make_ptr( context, context->SegCs, context->Eip, TRUE );
 445     if (!instr) return ExceptionContinueSearch;
 446
 447     /* First handle any possible prefix */
 448
 449     segprefix = -1;  /* no prefix */
 450     prefix = 1;
 451     repX = 0;
 452     prefixlen = 0;
 453     while(prefix)
 454     {
 455         switch(*instr)
 456         {
 457         case 0x2e:
 458             segprefix = context->SegCs;
 459             break;
 460         case 0x36:
 461             segprefix = context->SegSs;
 462             break;
 463         case 0x3e:
 464             segprefix = context->SegDs;
 465             break;
 466         case 0x26:
 467             segprefix = context->SegEs;
 468             break;
 469         case 0x64:
 470             segprefix = context->SegFs;
 471             break;
 472         case 0x65:
 473             segprefix = context->SegGs;
 474             break;
 475         case 0x66:
 476             long_op = !long_op;  /* opcode size prefix */
 477             break;
 478         case 0x67:
 479             long_addr = !long_addr;  /* addr size prefix */
 480             break;
 481         case 0xf0:  /* lock */
 482             break;
 483         case 0xf2:  /* repne */
 484             repX = 1;
 485             break;
 486         case 0xf3:  /* repe */
 487             repX = 2;
 488             break;
 489         default:
 490             prefix = 0;  /* no more prefixes */
 491             break;
 492         }
 493         if (prefix)
 494         {
 495             instr++;
 496             prefixlen++;
 497         }
 498     }
 499
 500     /* Now look at the actual instruction */
 501
 502     switch(*instr)
 503     {
 504         case 0x07: /* pop es */
 505         case 0x17: /* pop ss */
 506         case 0x1f: /* pop ds */
 507             {
 508                 WORD seg = *(WORD *)get_stack( context );
 509                 if (INSTR_ReplaceSelector( context, &seg ))
 510                 {
 511                     switch(*instr)
 512                     {
 513                     case 0x07: context->SegEs = seg; break;
 514                     case 0x17: context->SegSs = seg; break;
 515                     case 0x1f: context->SegDs = seg; break;
 516                     }
 517                     add_stack(context, long_op ? 4 : 2);
 518                     context->Eip += prefixlen + 1;
 519                     return ExceptionContinueExecution;
 520                 }
 521             }
 522             break;  /* Unable to emulate it */
 523
 524         case 0x0f: /* extended instruction */
 525             switch(instr[1])
 526             {
 527             case 0x22: /* mov eax, crX */
 528                 switch (instr[2])
 529                 {
 530                 case 0xc0:
 531                         ERR("mov eax,cr0 at 0x%08x, EAX=0x%08x\n",
 532                             context->Eip,context->Eax );
 533                         context->Eip += prefixlen+3;
 534                         return ExceptionContinueExecution;
 535                 default:
 536                         break; /*fallthrough to bad instruction handling */
 537                 }
 538                 break; /*fallthrough to bad instruction handling */
 539             case 0x20: /* mov crX, eax */
 540                 switch (instr[2])
 541                 {
 542                 case 0xe0: /* mov cr4, eax */
 543                     /* CR4 register . See linux/arch/i386/mm/init.c, X86_CR4_ defs
 544                      * bit 0: VME       Virtual Mode Exception ?
 545                      * bit 1: PVI       Protected mode Virtual Interrupt
 546                      * bit 2: TSD       Timestamp disable
 547                      * bit 3: DE        Debugging extensions
 548                      * bit 4: PSE       Page size extensions
 549                      * bit 5: PAE   Physical address extension
 550                      * bit 6: MCE       Machine check enable
 551                      * bit 7: PGE   Enable global pages
 552                      * bit 8: PCE       Enable performance counters at IPL3
 553                      */
 554                     ERR("mov cr4,eax at 0x%08x\n",context->Eip);
 555                     context->Eax = 0;
 556                     context->Eip += prefixlen+3;
 557                     return ExceptionContinueExecution;
 558                 case 0xc0: /* mov cr0, eax */
 559                     ERR("mov cr0,eax at 0x%08x\n",context->Eip);
 560                     context->Eax = 0x10; /* FIXME: set more bits ? */
 561                     context->Eip += prefixlen+3;
 562                     return ExceptionContinueExecution;
 563                 default: /* fallthrough to illegal instruction */
 564                     break;
 565                 }
 566                 /* fallthrough to illegal instruction */
 567                 break;
 568             case 0x21: /* mov drX, eax */
 569                 switch (instr[2])
 570                 {
 571                 case 0xc8: /* mov dr1, eax */
 572                     TRACE("mov dr1,eax at 0x%08x\n",context->Eip);
 573                     context->Eax = context->Dr1;
 574                     context->Eip += prefixlen+3;
 575                     return ExceptionContinueExecution;
 576                 case 0xf8: /* mov dr7, eax */
 577                     TRACE("mov dr7,eax at 0x%08x\n",context->Eip);
 578                     context->Eax = 0x400;
 579                     context->Eip += prefixlen+3;
 580                     return ExceptionContinueExecution;
 581                 }
 582                 ERR("Unsupported DR register, eip+2 is %02x\n", instr[2]);
 583                 /* fallthrough to illegal instruction */
 584                 break;
 585             case 0x23: /* mov eax drX */
 586                 switch (instr[2])
 587                 {
 588                 case 0xc8: /* mov eax, dr1 */
 589                     context->Dr1 = context->Eax;
 590                     context->Eip += prefixlen+3;
 591                     return ExceptionContinueExecution;
 592                 }
 593                 ERR("Unsupported DR register, eip+2 is %02x\n", instr[2]);
 594                 /* fallthrough to illegal instruction */
 595                 break;
 596             case 0xa1: /* pop fs */
 597                 {
 598                     WORD seg = *(WORD *)get_stack( context );
 599                     if (INSTR_ReplaceSelector( context, &seg ))
 600                     {
 601                         context->SegFs = seg;
 602                         add_stack(context, long_op ? 4 : 2);
 603                         context->Eip += prefixlen + 2;
 604                         return ExceptionContinueExecution;
 605                     }
 606                 }
 607                 break;
 608             case 0xa9: /* pop gs */
 609                 {
 610                     WORD seg = *(WORD *)get_stack( context );
 611                     if (INSTR_ReplaceSelector( context, &seg ))
 612                     {
 613                         context->SegGs = seg;
 614                         add_stack(context, long_op ? 4 : 2);
 615                         context->Eip += prefixlen + 2;
 616                         return ExceptionContinueExecution;
 617                     }
 618                 }
 619                 break;
 620             case 0xb2: /* lss addr,reg */
 621             case 0xb4: /* lfs addr,reg */
 622             case 0xb5: /* lgs addr,reg */
 623                 if (INSTR_EmulateLDS( context, instr, long_op,
 624                                       long_addr, segprefix, &len ))
 625                 {
 626                     context->Eip += prefixlen + len;
 627                     return ExceptionContinueExecution;
 628                 }
 629                 break;
 630             }
 631             break;  /* Unable to emulate it */
 632
 633         case 0x6c: /* insb     */
 634         case 0x6d: /* insw/d   */
 635         case 0x6e: /* outsb    */
 636         case 0x6f: /* outsw/d  */
 637             {
 638               int typ = *instr;  /* Just in case it's overwritten.  */
 639               int outp = (typ >= 0x6e);
 640               unsigned long count = repX ?
 641                           (long_addr ? context->Ecx : LOWORD(context->Ecx)) : 1;
 642               int opsize = (typ & 1) ? (long_op ? 4 : 2) : 1;
 643               int step = (context->EFlags & 0x400) ? -opsize : +opsize;
 644               int seg = outp ? context->SegDs : context->SegEs;  /* FIXME: is this right? */
 645
 646               if (outp)
 647                 /* FIXME: Check segment is readable.  */
 648                 ;
 649               else
 650                 /* FIXME: Check segment is writable.  */
 651                 ;
 652
 653               if (repX)
 654               {
 655                 if (long_addr) context->Ecx = 0;
 656                 else SET_LOWORD(context->Ecx,0);
 657               }
 658
 659               while (count-- > 0)
 660                 {
 661                   void *data;
 662                   WORD dx = LOWORD(context->Edx);
 663                   if (outp)
 664                   {
 665                       data = make_ptr( context, seg, context->Esi, long_addr );
 666                       if (long_addr) context->Esi += step;
 667                       else ADD_LOWORD(context->Esi,step);
 668                   }
 669                   else
 670                   {
 671                       data = make_ptr( context, seg, context->Edi, long_addr );
 672                       if (long_addr) context->Edi += step;
 673                       else ADD_LOWORD(context->Edi,step);
 674                   }
 675
 676                   switch (typ)
 677                   {
 678                     case 0x6c:
 679                       *(BYTE *)data = INSTR_inport( dx, 1, context );
 680                       break;
 681                     case 0x6d:
 682                       if (long_op)
 683                           *(DWORD *)data = INSTR_inport( dx, 4, context );
 684                       else
 685                           *(WORD *)data = INSTR_inport( dx, 2, context );
 686                       break;
 687                     case 0x6e:
 688                         INSTR_outport( dx, 1, *(BYTE *)data, context );
 689                         break;
 690                     case 0x6f:
 691                         if (long_op)
 692                             INSTR_outport( dx, 4, *(DWORD *)data, context );
 693                         else
 694                             INSTR_outport( dx, 2, *(WORD *)data, context );
 695                         break;
 696                     }
 697                 }
 698               context->Eip += prefixlen + 1;
 699             }
 700             return ExceptionContinueExecution;
 701
 702         case 0x8b: /* mov Ev, Gv */
 703             {
 704                 BYTE *addr = INSTR_GetOperandAddr(context, instr + 1, long_addr,
 705                                                   segprefix, &len);
 706                 struct idtr idtr = get_idtr();
 707                 unsigned int offset = addr - idtr.base;
 708
 709                 if (offset <= idtr.limit + 1 - (long_op ? 4 : 2))
 710                 {
 711                     idt[1].LimitLow = 0x100; /* FIXME */
 712                     idt[2].LimitLow = 0x11E; /* FIXME */
 713                     idt[3].LimitLow = 0x500; /* FIXME */
 714                     store_reg( context, instr[1], (BYTE *)idt + offset, long_op );
 715                     context->Eip += prefixlen + len + 1;
 716                     return ExceptionContinueExecution;
 717                 }
 718             }
 719             break;  /* Unable to emulate it */
 720
 721         case 0x8e: /* mov XX,segment_reg */
 722             {
 723                 WORD seg;
 724                 BYTE *addr = INSTR_GetOperandAddr(context, instr + 1,
 725                                                   long_addr, segprefix, &len );
 726                 if (!addr)
 727                     break;  /* Unable to emulate it */
 728                 seg = *(WORD *)addr;
 729                 if (!INSTR_ReplaceSelector( context, &seg ))
 730                     break;  /* Unable to emulate it */
 731
 732                 switch((instr[1] >> 3) & 7)
 733                 {
 734                 case 0:
 735                     context->SegEs = seg;
 736                     context->Eip += prefixlen + len + 1;
 737                     return ExceptionContinueExecution;
 738                 case 1:  /* cs */
 739                     break;
 740                 case 2:
 741                     context->SegSs = seg;
 742                     context->Eip += prefixlen + len + 1;
 743                     return ExceptionContinueExecution;
 744                 case 3:
 745                     context->SegDs = seg;
 746                     context->Eip += prefixlen + len + 1;
 747                     return ExceptionContinueExecution;
 748                 case 4:
 749                     context->SegFs = seg;
 750                     context->Eip += prefixlen + len + 1;
 751                     return ExceptionContinueExecution;
 752                 case 5:
 753                     context->SegGs = seg;
 754                     context->Eip += prefixlen + len + 1;
 755                     return ExceptionContinueExecution;
 756                 case 6:  /* unused */
 757                 case 7:  /* unused */
 758                     break;
 759                 }
 760             }
 761             break;  /* Unable to emulate it */
 762
 763         case 0xc4: /* les addr,reg */
 764         case 0xc5: /* lds addr,reg */
 765             if (INSTR_EmulateLDS( context, instr, long_op,
 766                                   long_addr, segprefix, &len ))
 767             {
 768                 context->Eip += prefixlen + len;
 769                 return ExceptionContinueExecution;
 770             }
 771             break;  /* Unable to emulate it */
 772
 773         case 0xcd: /* int <XX> */
 774             if (!winedos.EmulateInterruptPM) load_winedos();
 775             if (winedos.EmulateInterruptPM)
 776             {
 777                 context->Eip += prefixlen + 2;
 778                 if (winedos.EmulateInterruptPM( context, instr[1] )) return ExceptionContinueExecution;
 779                 context->Eip -= prefixlen + 2;  /* restore eip */
 780             }
 781             break;  /* Unable to emulate it */
 782
 783         case 0xcf: /* iret */
 784             if (wine_ldt_is_system(context->SegCs)) break;  /* don't emulate it in 32-bit code */
 785             if (long_op)
 786             {
 787                 DWORD *stack = get_stack( context );
 788                 context->Eip = *stack++;
 789                 context->SegCs  = *stack++;
 790                 context->EFlags = *stack;
 791                 add_stack(context, 3*sizeof(DWORD));  /* Pop the return address and flags */
 792             }
 793             else
 794             {
 795                 WORD *stack = get_stack( context );
 796                 context->Eip = *stack++;
 797                 context->SegCs  = *stack++;
 798                 SET_LOWORD(context->EFlags,*stack);
 799                 add_stack(context, 3*sizeof(WORD));  /* Pop the return address and flags */
 800             }
 801             return ExceptionContinueExecution;
 802
 803         case 0xe4: /* inb al,XX */
 804             SET_LOBYTE(context->Eax,INSTR_inport( instr[1], 1, context ));
 805             context->Eip += prefixlen + 2;
 806             return ExceptionContinueExecution;
 807
 808         case 0xe5: /* in (e)ax,XX */
 809             if (long_op)
 810                 context->Eax = INSTR_inport( instr[1], 4, context );
 811             else
 812                 SET_LOWORD(context->Eax, INSTR_inport( instr[1], 2, context ));
 813             context->Eip += prefixlen + 2;
 814             return ExceptionContinueExecution;
 815
 816         case 0xe6: /* outb XX,al */
 817             INSTR_outport( instr[1], 1, LOBYTE(context->Eax), context );
 818             context->Eip += prefixlen + 2;
 819             return ExceptionContinueExecution;
 820
 821         case 0xe7: /* out XX,(e)ax */
 822             if (long_op)
 823                 INSTR_outport( instr[1], 4, context->Eax, context );
 824             else
 825                 INSTR_outport( instr[1], 2, LOWORD(context->Eax), context );
 826             context->Eip += prefixlen + 2;
 827             return ExceptionContinueExecution;
 828
 829         case 0xec: /* inb al,dx */
 830             SET_LOBYTE(context->Eax, INSTR_inport( LOWORD(context->Edx), 1, context ) );
 831             context->Eip += prefixlen + 1;
 832             return ExceptionContinueExecution;
 833
 834         case 0xed: /* in (e)ax,dx */
 835             if (long_op)
 836                 context->Eax = INSTR_inport( LOWORD(context->Edx), 4, context );
 837             else
 838                 SET_LOWORD(context->Eax, INSTR_inport( LOWORD(context->Edx), 2, context ));
 839             context->Eip += prefixlen + 1;
 840             return ExceptionContinueExecution;
 841
 842         case 0xee: /* outb dx,al */
 843             INSTR_outport( LOWORD(context->Edx), 1, LOBYTE(context->Eax), context );
 844             context->Eip += prefixlen + 1;
 845             return ExceptionContinueExecution;
 846
 847         case 0xef: /* out dx,(e)ax */
 848             if (long_op)
 849                 INSTR_outport( LOWORD(context->Edx), 4, context->Eax, context );
 850             else
 851                 INSTR_outport( LOWORD(context->Edx), 2, LOWORD(context->Eax), context );
 852             context->Eip += prefixlen + 1;
 853             return ExceptionContinueExecution;
 854
 855         case 0xfa: /* cli */
 856             get_vm86_teb_info()->dpmi_vif = 0;
 857             context->Eip += prefixlen + 1;
 858             return ExceptionContinueExecution;
 859
 860         case 0xfb: /* sti */
 861             get_vm86_teb_info()->dpmi_vif = 1;
 862             context->Eip += prefixlen + 1;
 863             if (get_vm86_teb_info()->vm86_pending)
 864             {
 865                 get_vm86_teb_info()->vm86_pending = 0;
 866                 rec->ExceptionCode = EXCEPTION_VM86_STI;
 867                 break; /* Handle the pending event. */
 868             }
 869             return ExceptionContinueExecution;
 870     }
 871     return ExceptionContinueSearch;  /* Unable to emulate it */
 872 }
 873
 874
 875 /***********************************************************************
 876  *           INSTR_vectored_handler
 877  *
 878  * Vectored exception handler used to emulate protected instructions
 879  * from 32-bit code.
 880  */
 881 LONG CALLBACK INSTR_vectored_handler( EXCEPTION_POINTERS *ptrs )
 882 {
 883     EXCEPTION_RECORD *record = ptrs->ExceptionRecord;
 884     CONTEXT86 *context = ptrs->ContextRecord;
 885
 886     if (wine_ldt_is_system(context->SegCs) &&
 887         (record->ExceptionCode == EXCEPTION_ACCESS_VIOLATION ||
 888          record->ExceptionCode == EXCEPTION_PRIV_INSTRUCTION))
 889     {
 890         if (__wine_emulate_instruction( record, context ) == ExceptionContinueExecution)
 891             return EXCEPTION_CONTINUE_EXECUTION;
 892     }
 893     return EXCEPTION_CONTINUE_SEARCH;
 894 }
 895
 896
 897 /***********************************************************************
 898  *           INSTR_CallBuiltinHandler
 899  */
 900 static void INSTR_CallBuiltinHandler( CONTEXT86 *context, BYTE intnum )
 901 {
 902     if (!winedos.CallBuiltinHandler) load_winedos();
 903     if (winedos.CallBuiltinHandler) winedos.CallBuiltinHandler( context, intnum );
 904 }
 905
 906
 907 /***********************************************************************
 908  *           DOS3Call         (KERNEL.102)
 909  */
 910 void WINAPI DOS3Call( CONTEXT86 *context )
 911 {
 912     INSTR_CallBuiltinHandler( context, 0x21 );
 913 }
 914
 915
 916 /***********************************************************************
 917  *           NetBIOSCall      (KERNEL.103)
 918  */
 919 void WINAPI NetBIOSCall16( CONTEXT86 *context )
 920 {
 921     INSTR_CallBuiltinHandler( context, 0x5c );
 922 }
 923
 924
 925 /***********************************************************************
 926  *              GetSetKernelDOSProc (KERNEL.311)
 927  */
 928 FARPROC16 WINAPI GetSetKernelDOSProc16( FARPROC16 DosProc )
 929 {
 930     FIXME("(DosProc=%p): stub\n", DosProc);
 931     return NULL;
 932 }
 933
 934 #endif  /* __i386__ */