dlls/krnl386.exe16/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 #include <stdarg.h>
  27
  28 #include "windef.h"
  29 #include "winbase.h"
  30 #include "winternl.h"
  31 #include "wine/winuser16.h"
  32 #include "excpt.h"
  33 #include "wine/debug.h"
  34 #include "kernel16_private.h"
  35 #include "dosexe.h"
  36 #include "wine/exception.h"
  37
  38 WINE_DEFAULT_DEBUG_CHANNEL(int);
  39 WINE_DECLARE_DEBUG_CHANNEL(io);
  40
  41 /* macros to set parts of a DWORD */
  42 #define SET_LOWORD(dw,val)  ((dw) = ((dw) & 0xffff0000) | LOWORD(val))
  43 #define SET_LOBYTE(dw,val)  ((dw) = ((dw) & 0xffffff00) | LOBYTE(val))
  44 #define ADD_LOWORD(dw,val)  ((dw) = ((dw) & 0xffff0000) | LOWORD((DWORD)(dw)+(val)))
  45 #define ISV86(context)      ((context)->EFlags & 0x00020000)
  46
  47 static inline void add_stack( CONTEXT *context, int offset )
  48 {
  49     if (ISV86(context) || !IS_SELECTOR_32BIT(context->SegSs))
  50         ADD_LOWORD( context->Esp, offset );
  51     else
  52         context->Esp += offset;
  53 }
  54
  55 static inline void *make_ptr( CONTEXT *context, DWORD seg, DWORD off, int long_addr )
  56 {
  57     if (ISV86(context)) return (void *)((seg << 4) + LOWORD(off));
  58     if (wine_ldt_is_system(seg)) return (void *)off;
  59     if (!long_addr) off = LOWORD(off);
  60     return (char *) MapSL( MAKESEGPTR( seg, 0 ) ) + off;
  61 }
  62
  63 static inline void *get_stack( CONTEXT *context )
  64 {
  65     if (ISV86(context)) return (void *)((context->SegSs << 4) + LOWORD(context->Esp));
  66     return wine_ldt_get_ptr( context->SegSs, context->Esp );
  67 }
  68
  69 #include "pshpack1.h"
  70 struct idtr
  71 {
  72     WORD  limit;
  73     BYTE *base;
  74 };
  75 #include "poppack.h"
  76
  77 static LDT_ENTRY idt[256];
  78
  79 static inline struct idtr get_idtr(void)
  80 {
  81     struct idtr ret;
  82 #if defined(__i386__) && defined(__GNUC__)
  83     __asm__( "sidtl %0" : "=m" (ret) );
  84 #else
  85     ret.base = (BYTE *)idt;
  86     ret.limit = sizeof(idt) - 1;
  87 #endif
  88     return ret;
  89 }
  90
  91
  92 /***********************************************************************
  93  *           INSTR_ReplaceSelector
  94  *
  95  * Try to replace an invalid selector by a valid one.
  96  * The only selector where it is allowed to do "mov ax,40;mov es,ax"
  97  * is the so called 'bimodal' selector 0x40, which points to the BIOS
  98  * data segment. Used by (at least) Borland products (and programs compiled
  99  * using Borland products).
 100  *
 101  * See Undocumented Windows, Chapter 5, __0040.
 102  */
 103 static BOOL INSTR_ReplaceSelector( CONTEXT *context, WORD *sel )
 104 {
 105     if (*sel == 0x40)
 106     {
 107         DOSVM_start_bios_timer();
 108         *sel = DOSMEM_BiosDataSeg;
 109         return TRUE;
 110     }
 111     return FALSE;  /* Can't replace selector, crashdump */
 112 }
 113
 114
 115 /* store an operand into a register */
 116 static void store_reg( CONTEXT *context, BYTE regmodrm, const BYTE *addr, int long_op )
 117 {
 118     switch((regmodrm >> 3) & 7)
 119     {
 120     case 0:
 121         if (long_op) context->Eax = *(const DWORD *)addr;
 122         else SET_LOWORD(context->Eax, *(const WORD *)addr);
 123         break;
 124     case 1:
 125         if (long_op) context->Ecx = *(const DWORD *)addr;
 126         else SET_LOWORD(context->Ecx, *(const WORD *)addr);
 127         break;
 128     case 2:
 129         if (long_op) context->Edx = *(const DWORD *)addr;
 130         else SET_LOWORD(context->Edx, *(const WORD *)addr);
 131         break;
 132     case 3:
 133         if (long_op) context->Ebx = *(const DWORD *)addr;
 134         else SET_LOWORD(context->Ebx, *(const WORD *)addr);
 135         break;
 136     case 4:
 137         if (long_op) context->Esp = *(const DWORD *)addr;
 138         else SET_LOWORD(context->Esp, *(const WORD *)addr);
 139         break;
 140     case 5:
 141         if (long_op) context->Ebp = *(const DWORD *)addr;
 142         else SET_LOWORD(context->Ebp, *(const WORD *)addr);
 143         break;
 144     case 6:
 145         if (long_op) context->Esi = *(const DWORD *)addr;
 146         else SET_LOWORD(context->Esi, *(const WORD *)addr);
 147         break;
 148     case 7:
 149         if (long_op) context->Edi = *(const DWORD *)addr;
 150         else SET_LOWORD(context->Edi, *(const WORD *)addr);
 151         break;
 152     }
 153 }
 154
 155 /***********************************************************************
 156  *           INSTR_GetOperandAddr
 157  *
 158  * Return the address of an instruction operand (from the mod/rm byte).
 159  */
 160 static BYTE *INSTR_GetOperandAddr( CONTEXT *context, BYTE *instr,
 161                                    int long_addr, int segprefix, int *len )
 162 {
 163     int mod, rm, base = 0, index = 0, ss = 0, seg = 0, off;
 164     LDT_ENTRY entry;
 165
 166 #define GET_VAL(val,type) \
 167     { *val = *(type *)instr; instr += sizeof(type); *len += sizeof(type); }
 168
 169     *len = 0;
 170     GET_VAL( &mod, BYTE );
 171     rm = mod & 7;
 172     mod >>= 6;
 173
 174     if (mod == 3)
 175     {
 176         switch(rm)
 177         {
 178         case 0: return (BYTE *)&context->Eax;
 179         case 1: return (BYTE *)&context->Ecx;
 180         case 2: return (BYTE *)&context->Edx;
 181         case 3: return (BYTE *)&context->Ebx;
 182         case 4: return (BYTE *)&context->Esp;
 183         case 5: return (BYTE *)&context->Ebp;
 184         case 6: return (BYTE *)&context->Esi;
 185         case 7: return (BYTE *)&context->Edi;
 186         }
 187     }
 188
 189     if (long_addr)
 190     {
 191         if (rm == 4)
 192         {
 193             BYTE sib;
 194             GET_VAL( &sib, BYTE );
 195             rm = sib & 7;
 196             ss = sib >> 6;
 197             switch(sib >> 3)
 198             {
 199             case 0: index = context->Eax; break;
 200             case 1: index = context->Ecx; break;
 201             case 2: index = context->Edx; break;
 202             case 3: index = context->Ebx; break;
 203             case 4: index = 0; break;
 204             case 5: index = context->Ebp; break;
 205             case 6: index = context->Esi; break;
 206             case 7: index = context->Edi; break;
 207             }
 208         }
 209
 210         switch(rm)
 211         {
 212         case 0: base = context->Eax; seg = context->SegDs; break;
 213         case 1: base = context->Ecx; seg = context->SegDs; break;
 214         case 2: base = context->Edx; seg = context->SegDs; break;
 215         case 3: base = context->Ebx; seg = context->SegDs; break;
 216         case 4: base = context->Esp; seg = context->SegSs; break;
 217         case 5: base = context->Ebp; seg = context->SegSs; break;
 218         case 6: base = context->Esi; seg = context->SegDs; break;
 219         case 7: base = context->Edi; seg = context->SegDs; break;
 220         }
 221         switch (mod)
 222         {
 223         case 0:
 224             if (rm == 5)  /* special case: ds:(disp32) */
 225             {
 226                 GET_VAL( &base, DWORD );
 227                 seg = context->SegDs;
 228             }
 229             break;
 230
 231         case 1:  /* 8-bit disp */
 232             GET_VAL( &off, BYTE );
 233             base += (signed char)off;
 234             break;
 235
 236         case 2:  /* 32-bit disp */
 237             GET_VAL( &off, DWORD );
 238             base += (signed long)off;
 239             break;
 240         }
 241     }
 242     else  /* short address */
 243     {
 244         switch(rm)
 245         {
 246         case 0:  /* ds:(bx,si) */
 247             base = LOWORD(context->Ebx) + LOWORD(context->Esi);
 248             seg  = context->SegDs;
 249             break;
 250         case 1:  /* ds:(bx,di) */
 251             base = LOWORD(context->Ebx) + LOWORD(context->Edi);
 252             seg  = context->SegDs;
 253             break;
 254         case 2:  /* ss:(bp,si) */
 255             base = LOWORD(context->Ebp) + LOWORD(context->Esi);
 256             seg  = context->SegSs;
 257             break;
 258         case 3:  /* ss:(bp,di) */
 259             base = LOWORD(context->Ebp) + LOWORD(context->Edi);
 260             seg  = context->SegSs;
 261             break;
 262         case 4:  /* ds:(si) */
 263             base = LOWORD(context->Esi);
 264             seg  = context->SegDs;
 265             break;
 266         case 5:  /* ds:(di) */
 267             base = LOWORD(context->Edi);
 268             seg  = context->SegDs;
 269             break;
 270         case 6:  /* ss:(bp) */
 271             base = LOWORD(context->Ebp);
 272             seg  = context->SegSs;
 273             break;
 274         case 7:  /* ds:(bx) */
 275             base = LOWORD(context->Ebx);
 276             seg  = context->SegDs;
 277             break;
 278         }
 279
 280         switch(mod)
 281         {
 282         case 0:
 283             if (rm == 6)  /* special case: ds:(disp16) */
 284             {
 285                 GET_VAL( &base, WORD );
 286                 seg  = context->SegDs;
 287             }
 288             break;
 289
 290         case 1:  /* 8-bit disp */
 291             GET_VAL( &off, BYTE );
 292             base += (signed char)off;
 293             break;
 294
 295         case 2:  /* 16-bit disp */
 296             GET_VAL( &off, WORD );
 297             base += (signed short)off;
 298             break;
 299         }
 300         base &= 0xffff;
 301     }
 302     if (segprefix != -1) seg = segprefix;
 303
 304     /* Make sure the segment and offset are valid */
 305     if (wine_ldt_is_system(seg)) return (BYTE *)(base + (index << ss));
 306     if ((seg & 7) != 7) return NULL;
 307     wine_ldt_get_entry( seg, &entry );
 308     if (wine_ldt_is_empty( &entry )) return NULL;
 309     if (wine_ldt_get_limit(&entry) < (base + (index << ss))) return NULL;
 310     return (BYTE *)wine_ldt_get_base(&entry) + base + (index << ss);
 311 #undef GET_VAL
 312 }
 313
 314
 315 /***********************************************************************
 316  *           INSTR_EmulateLDS
 317  *
 318  * Emulate the LDS (and LES,LFS,etc.) instruction.
 319  */
 320 static BOOL INSTR_EmulateLDS( CONTEXT *context, BYTE *instr, int long_op,
 321                               int long_addr, int segprefix, int *len )
 322 {
 323     WORD seg;
 324     BYTE *regmodrm = instr + 1 + (*instr == 0x0f);
 325     BYTE *addr = INSTR_GetOperandAddr( context, regmodrm,
 326                                        long_addr, segprefix, len );
 327     if (!addr)
 328         return FALSE;  /* Unable to emulate it */
 329     seg = *(WORD *)(addr + (long_op ? 4 : 2));
 330
 331     if (!INSTR_ReplaceSelector( context, &seg ))
 332         return FALSE;  /* Unable to emulate it */
 333
 334     /* Now store the offset in the correct register */
 335
 336     store_reg( context, *regmodrm, addr, long_op );
 337
 338     /* Store the correct segment in the segment register */
 339
 340     switch(*instr)
 341     {
 342     case 0xc4: context->SegEs = seg; break;  /* les */
 343     case 0xc5: context->SegDs = seg; break;  /* lds */
 344     case 0x0f: switch(instr[1])
 345                {
 346                case 0xb2: context->SegSs = seg; break;  /* lss */
 347                case 0xb4: context->SegFs = seg; break;  /* lfs */
 348                case 0xb5: context->SegGs = seg; break;  /* lgs */
 349                }
 350                break;
 351     }
 352
 353     /* Add the opcode size to the total length */
 354
 355     *len += 1 + (*instr == 0x0f);
 356     return TRUE;
 357 }
 358
 359 /***********************************************************************
 360  *           INSTR_inport
 361  *
 362  * input on an I/O port
 363  */
 364 static DWORD INSTR_inport( WORD port, int size, CONTEXT *context )
 365 {
 366     DWORD res = DOSVM_inport( port, size );
 367
 368     if (TRACE_ON(io))
 369     {
 370         switch(size)
 371         {
 372         case 1:
 373             TRACE_(io)( "0x%x < %02x @ %04x:%04x\n", port, LOBYTE(res),
 374                      (WORD)context->SegCs, LOWORD(context->Eip));
 375             break;
 376         case 2:
 377             TRACE_(io)( "0x%x < %04x @ %04x:%04x\n", port, LOWORD(res),
 378                      (WORD)context->SegCs, LOWORD(context->Eip));
 379             break;
 380         case 4:
 381             TRACE_(io)( "0x%x < %08x @ %04x:%04x\n", port, res,
 382                      (WORD)context->SegCs, LOWORD(context->Eip));
 383             break;
 384         }
 385     }
 386     return res;
 387 }
 388
 389
 390 /***********************************************************************
 391  *           INSTR_outport
 392  *
 393  * output on an I/O port
 394  */
 395 static void INSTR_outport( WORD port, int size, DWORD val, CONTEXT *context )
 396 {
 397     DOSVM_outport( port, size, val );
 398
 399     if (TRACE_ON(io))
 400     {
 401         switch(size)
 402         {
 403         case 1:
 404             TRACE_(io)("0x%x > %02x @ %04x:%04x\n", port, LOBYTE(val),
 405                     (WORD)context->SegCs, LOWORD(context->Eip));
 406             break;
 407         case 2:
 408             TRACE_(io)("0x%x > %04x @ %04x:%04x\n", port, LOWORD(val),
 409                     (WORD)context->SegCs, LOWORD(context->Eip));
 410             break;
 411         case 4:
 412             TRACE_(io)("0x%x > %08x @ %04x:%04x\n", port, val,
 413                     (WORD)context->SegCs, LOWORD(context->Eip));
 414             break;
 415         }
 416     }
 417 }
 418
 419
 420 /***********************************************************************
 421  *           __wine_emulate_instruction
 422  *
 423  * Emulate a privileged instruction.
 424  * Returns exception continuation status.
 425  */
 426 DWORD __wine_emulate_instruction( EXCEPTION_RECORD *rec, CONTEXT *context )
 427 {
 428     int prefix, segprefix, prefixlen, len, repX, long_op, long_addr;
 429     BYTE *instr;
 430
 431     long_op = long_addr = (!ISV86(context) && IS_SELECTOR_32BIT(context->SegCs));
 432     instr = make_ptr( context, context->SegCs, context->Eip, TRUE );
 433     if (!instr) return ExceptionContinueSearch;
 434
 435     /* First handle any possible prefix */
 436
 437     segprefix = -1;  /* no prefix */
 438     prefix = 1;
 439     repX = 0;
 440     prefixlen = 0;
 441     while(prefix)
 442     {
 443         switch(*instr)
 444         {
 445         case 0x2e:
 446             segprefix = context->SegCs;
 447             break;
 448         case 0x36:
 449             segprefix = context->SegSs;
 450             break;
 451         case 0x3e:
 452             segprefix = context->SegDs;
 453             break;
 454         case 0x26:
 455             segprefix = context->SegEs;
 456             break;
 457         case 0x64:
 458             segprefix = context->SegFs;
 459             break;
 460         case 0x65:
 461             segprefix = context->SegGs;
 462             break;
 463         case 0x66:
 464             long_op = !long_op;  /* opcode size prefix */
 465             break;
 466         case 0x67:
 467             long_addr = !long_addr;  /* addr size prefix */
 468             break;
 469         case 0xf0:  /* lock */
 470             break;
 471         case 0xf2:  /* repne */
 472             repX = 1;
 473             break;
 474         case 0xf3:  /* repe */
 475             repX = 2;
 476             break;
 477         default:
 478             prefix = 0;  /* no more prefixes */
 479             break;
 480         }
 481         if (prefix)
 482         {
 483             instr++;
 484             prefixlen++;
 485         }
 486     }
 487
 488     /* Now look at the actual instruction */
 489
 490     switch(*instr)
 491     {
 492         case 0x07: /* pop es */
 493         case 0x17: /* pop ss */
 494         case 0x1f: /* pop ds */
 495             {
 496                 WORD seg = *(WORD *)get_stack( context );
 497                 if (INSTR_ReplaceSelector( context, &seg ))
 498                 {
 499                     switch(*instr)
 500                     {
 501                     case 0x07: context->SegEs = seg; break;
 502                     case 0x17: context->SegSs = seg; break;
 503                     case 0x1f: context->SegDs = seg; break;
 504                     }
 505                     add_stack(context, long_op ? 4 : 2);
 506                     context->Eip += prefixlen + 1;
 507                     return ExceptionContinueExecution;
 508                 }
 509             }
 510             break;  /* Unable to emulate it */
 511
 512         case 0x0f: /* extended instruction */
 513             switch(instr[1])
 514             {
 515             case 0x22: /* mov %eax, %crX */
 516                 switch (instr[2])
 517                 {
 518                 case 0xc0:
 519                     FIXME("mov %%eax, %%cr0 at 0x%08x, EAX=0x%08x\n",
 520                           context->Eip,context->Eax );
 521                           context->Eip += prefixlen+3;
 522                     return ExceptionContinueExecution;
 523                 default:
 524                     break; /* Fallthrough to bad instruction handling */
 525                 }
 526                 break; /* Fallthrough to bad instruction handling */
 527             case 0x20: /* mov %crX, %eax */
 528                 switch (instr[2])
 529                 {
 530                 case 0xe0: /* mov %cr4, %eax */
 531                     /* CR4 register: See linux/arch/i386/mm/init.c, X86_CR4_ defs
 532                      * bit 0: VME Virtual Mode Exception ?
 533                      * bit 1: PVI Protected mode Virtual Interrupt
 534                      * bit 2: TSD Timestamp disable
 535                      * bit 3: DE  Debugging extensions
 536                      * bit 4: PSE Page size extensions
 537                      * bit 5: PAE Physical address extension
 538                      * bit 6: MCE Machine check enable
 539                      * bit 7: PGE Enable global pages
 540                      * bit 8: PCE Enable performance counters at IPL3
 541                      */
 542                     FIXME("mov %%cr4, %%eax at 0x%08x\n",context->Eip);
 543                     context->Eax = 0;
 544                     context->Eip += prefixlen+3;
 545                     return ExceptionContinueExecution;
 546                 case 0xc0: /* mov %cr0, %eax */
 547                     FIXME("mov %%cr0, %%eax at 0x%08x\n",context->Eip);
 548                     context->Eax = 0x10; /* FIXME: set more bits ? */
 549                     context->Eip += prefixlen+3;
 550                     return ExceptionContinueExecution;
 551                 default: /* Fallthrough to illegal instruction */
 552                     break;
 553                 }
 554                 /* Fallthrough to illegal instruction */
 555                 break;
 556             case 0x21: /* mov %drX, %eax */
 557                 switch (instr[2])
 558                 {
 559                 case 0xc8: /* mov %dr1, %eax */
 560                     TRACE("mov %%dr1, %%eax at 0x%08x\n",context->Eip);
 561                     context->Eax = context->Dr1;
 562                     context->Eip += prefixlen+3;
 563                     return ExceptionContinueExecution;
 564                 case 0xf8: /* mov %dr7, %eax */
 565                     TRACE("mov %%dr7, %%eax at 0x%08x\n",context->Eip);
 566                     context->Eax = 0x400;
 567                     context->Eip += prefixlen+3;
 568                     return ExceptionContinueExecution;
 569                 }
 570                 FIXME("Unsupported DR register, eip+2 is %02x\n", instr[2]);
 571                 /* fallthrough to illegal instruction */
 572                 break;
 573             case 0x23: /* mov %eax, %drX */
 574                 switch (instr[2])
 575                 {
 576                 case 0xc8: /* mov %eax, %dr1 */
 577                     context->Dr1 = context->Eax;
 578                     context->Eip += prefixlen+3;
 579                     return ExceptionContinueExecution;
 580                 }
 581                 FIXME("Unsupported DR register, eip+2 is %02x\n", instr[2]);
 582                 /* fallthrough to illegal instruction */
 583                 break;
 584             case 0xa1: /* pop fs */
 585                 {
 586                     WORD seg = *(WORD *)get_stack( context );
 587                     if (INSTR_ReplaceSelector( context, &seg ))
 588                     {
 589                         context->SegFs = seg;
 590                         add_stack(context, long_op ? 4 : 2);
 591                         context->Eip += prefixlen + 2;
 592                         return ExceptionContinueExecution;
 593                     }
 594                 }
 595                 break;
 596             case 0xa9: /* pop gs */
 597                 {
 598                     WORD seg = *(WORD *)get_stack( context );
 599                     if (INSTR_ReplaceSelector( context, &seg ))
 600                     {
 601                         context->SegGs = seg;
 602                         add_stack(context, long_op ? 4 : 2);
 603                         context->Eip += prefixlen + 2;
 604                         return ExceptionContinueExecution;
 605                     }
 606                 }
 607                 break;
 608             case 0xb2: /* lss addr,reg */
 609             case 0xb4: /* lfs addr,reg */
 610             case 0xb5: /* lgs addr,reg */
 611                 if (INSTR_EmulateLDS( context, instr, long_op,
 612                                       long_addr, segprefix, &len ))
 613                 {
 614                     context->Eip += prefixlen + len;
 615                     return ExceptionContinueExecution;
 616                 }
 617                 break;
 618             }
 619             break;  /* Unable to emulate it */
 620
 621         case 0x6c: /* insb     */
 622         case 0x6d: /* insw/d   */
 623         case 0x6e: /* outsb    */
 624         case 0x6f: /* outsw/d  */
 625             {
 626               int typ = *instr;  /* Just in case it's overwritten.  */
 627               int outp = (typ >= 0x6e);
 628               unsigned long count = repX ?
 629                           (long_addr ? context->Ecx : LOWORD(context->Ecx)) : 1;
 630               int opsize = (typ & 1) ? (long_op ? 4 : 2) : 1;
 631               int step = (context->EFlags & 0x400) ? -opsize : +opsize;
 632               int seg = outp ? context->SegDs : context->SegEs;  /* FIXME: is this right? */
 633
 634               if (outp)
 635               {
 636                 /* FIXME: Check segment is readable.  */
 637               }
 638               else
 639               {
 640                 /* FIXME: Check segment is writable.  */
 641               }
 642
 643               if (repX)
 644               {
 645                 if (long_addr) context->Ecx = 0;
 646                 else SET_LOWORD(context->Ecx,0);
 647               }
 648
 649               while (count-- > 0)
 650                 {
 651                   void *data;
 652                   WORD dx = LOWORD(context->Edx);
 653                   if (outp)
 654                   {
 655                       data = make_ptr( context, seg, context->Esi, long_addr );
 656                       if (long_addr) context->Esi += step;
 657                       else ADD_LOWORD(context->Esi,step);
 658                   }
 659                   else
 660                   {
 661                       data = make_ptr( context, seg, context->Edi, long_addr );
 662                       if (long_addr) context->Edi += step;
 663                       else ADD_LOWORD(context->Edi,step);
 664                   }
 665
 666                   switch (typ)
 667                   {
 668                     case 0x6c:
 669                       *(BYTE *)data = INSTR_inport( dx, 1, context );
 670                       break;
 671                     case 0x6d:
 672                       if (long_op)
 673                           *(DWORD *)data = INSTR_inport( dx, 4, context );
 674                       else
 675                           *(WORD *)data = INSTR_inport( dx, 2, context );
 676                       break;
 677                     case 0x6e:
 678                         INSTR_outport( dx, 1, *(BYTE *)data, context );
 679                         break;
 680                     case 0x6f:
 681                         if (long_op)
 682                             INSTR_outport( dx, 4, *(DWORD *)data, context );
 683                         else
 684                             INSTR_outport( dx, 2, *(WORD *)data, context );
 685                         break;
 686                     }
 687                 }
 688               context->Eip += prefixlen + 1;
 689             }
 690             return ExceptionContinueExecution;
 691
 692         case 0x8b: /* mov Ev, Gv */
 693             {
 694                 BYTE *addr = INSTR_GetOperandAddr(context, instr + 1, long_addr,
 695                                                   segprefix, &len);
 696                 struct idtr idtr = get_idtr();
 697                 unsigned int offset = addr - idtr.base;
 698
 699                 if (offset <= idtr.limit + 1 - (long_op ? 4 : 2))
 700                 {
 701                     idt[1].LimitLow = 0x100; /* FIXME */
 702                     idt[2].LimitLow = 0x11E; /* FIXME */
 703                     idt[3].LimitLow = 0x500; /* FIXME */
 704                     store_reg( context, instr[1], (BYTE *)idt + offset, long_op );
 705                     context->Eip += prefixlen + len + 1;
 706                     return ExceptionContinueExecution;
 707                 }
 708             }
 709             break;  /* Unable to emulate it */
 710
 711         case 0x8e: /* mov XX,segment_reg */
 712             {
 713                 WORD seg;
 714                 BYTE *addr = INSTR_GetOperandAddr(context, instr + 1,
 715                                                   long_addr, segprefix, &len );
 716                 if (!addr)
 717                     break;  /* Unable to emulate it */
 718                 seg = *(WORD *)addr;
 719                 if (!INSTR_ReplaceSelector( context, &seg ))
 720                     break;  /* Unable to emulate it */
 721
 722                 switch((instr[1] >> 3) & 7)
 723                 {
 724                 case 0:
 725                     context->SegEs = seg;
 726                     context->Eip += prefixlen + len + 1;
 727                     return ExceptionContinueExecution;
 728                 case 1:  /* cs */
 729                     break;
 730                 case 2:
 731                     context->SegSs = seg;
 732                     context->Eip += prefixlen + len + 1;
 733                     return ExceptionContinueExecution;
 734                 case 3:
 735                     context->SegDs = seg;
 736                     context->Eip += prefixlen + len + 1;
 737                     return ExceptionContinueExecution;
 738                 case 4:
 739                     context->SegFs = seg;
 740                     context->Eip += prefixlen + len + 1;
 741                     return ExceptionContinueExecution;
 742                 case 5:
 743                     context->SegGs = seg;
 744                     context->Eip += prefixlen + len + 1;
 745                     return ExceptionContinueExecution;
 746                 case 6:  /* unused */
 747                 case 7:  /* unused */
 748                     break;
 749                 }
 750             }
 751             break;  /* Unable to emulate it */
 752
 753         case 0xc4: /* les addr,reg */
 754         case 0xc5: /* lds addr,reg */
 755             if (INSTR_EmulateLDS( context, instr, long_op,
 756                                   long_addr, segprefix, &len ))
 757             {
 758                 context->Eip += prefixlen + len;
 759                 return ExceptionContinueExecution;
 760             }
 761             break;  /* Unable to emulate it */
 762
 763         case 0xcd: /* int <XX> */
 764             context->Eip += prefixlen + 2;
 765             if (DOSVM_EmulateInterruptPM( context, instr[1] )) return ExceptionContinueExecution;
 766             context->Eip -= prefixlen + 2;  /* restore eip */
 767             break;  /* Unable to emulate it */
 768
 769         case 0xcf: /* iret */
 770             if (wine_ldt_is_system(context->SegCs)) break;  /* don't emulate it in 32-bit code */
 771             if (long_op)
 772             {
 773                 DWORD *stack = get_stack( context );
 774                 context->Eip = *stack++;
 775                 context->SegCs  = *stack++;
 776                 context->EFlags = *stack;
 777                 add_stack(context, 3*sizeof(DWORD));  /* Pop the return address and flags */
 778             }
 779             else
 780             {
 781                 WORD *stack = get_stack( context );
 782                 context->Eip = *stack++;
 783                 context->SegCs  = *stack++;
 784                 SET_LOWORD(context->EFlags,*stack);
 785                 add_stack(context, 3*sizeof(WORD));  /* Pop the return address and flags */
 786             }
 787             return ExceptionContinueExecution;
 788
 789         case 0xe4: /* inb al,XX */
 790             SET_LOBYTE(context->Eax,INSTR_inport( instr[1], 1, context ));
 791             context->Eip += prefixlen + 2;
 792             return ExceptionContinueExecution;
 793
 794         case 0xe5: /* in (e)ax,XX */
 795             if (long_op)
 796                 context->Eax = INSTR_inport( instr[1], 4, context );
 797             else
 798                 SET_LOWORD(context->Eax, INSTR_inport( instr[1], 2, context ));
 799             context->Eip += prefixlen + 2;
 800             return ExceptionContinueExecution;
 801
 802         case 0xe6: /* outb XX,al */
 803             INSTR_outport( instr[1], 1, LOBYTE(context->Eax), context );
 804             context->Eip += prefixlen + 2;
 805             return ExceptionContinueExecution;
 806
 807         case 0xe7: /* out XX,(e)ax */
 808             if (long_op)
 809                 INSTR_outport( instr[1], 4, context->Eax, context );
 810             else
 811                 INSTR_outport( instr[1], 2, LOWORD(context->Eax), context );
 812             context->Eip += prefixlen + 2;
 813             return ExceptionContinueExecution;
 814
 815         case 0xec: /* inb al,dx */
 816             SET_LOBYTE(context->Eax, INSTR_inport( LOWORD(context->Edx), 1, context ) );
 817             context->Eip += prefixlen + 1;
 818             return ExceptionContinueExecution;
 819
 820         case 0xed: /* in (e)ax,dx */
 821             if (long_op)
 822                 context->Eax = INSTR_inport( LOWORD(context->Edx), 4, context );
 823             else
 824                 SET_LOWORD(context->Eax, INSTR_inport( LOWORD(context->Edx), 2, context ));
 825             context->Eip += prefixlen + 1;
 826             return ExceptionContinueExecution;
 827
 828         case 0xee: /* outb dx,al */
 829             INSTR_outport( LOWORD(context->Edx), 1, LOBYTE(context->Eax), context );
 830             context->Eip += prefixlen + 1;
 831             return ExceptionContinueExecution;
 832
 833         case 0xef: /* out dx,(e)ax */
 834             if (long_op)
 835                 INSTR_outport( LOWORD(context->Edx), 4, context->Eax, context );
 836             else
 837                 INSTR_outport( LOWORD(context->Edx), 2, LOWORD(context->Eax), context );
 838             context->Eip += prefixlen + 1;
 839             return ExceptionContinueExecution;
 840
 841         case 0xfa: /* cli */
 842             get_vm86_teb_info()->dpmi_vif = 0;
 843             context->Eip += prefixlen + 1;
 844             return ExceptionContinueExecution;
 845
 846         case 0xfb: /* sti */
 847             get_vm86_teb_info()->dpmi_vif = 1;
 848             context->Eip += prefixlen + 1;
 849             if (get_vm86_teb_info()->vm86_pending)
 850             {
 851                 get_vm86_teb_info()->vm86_pending = 0;
 852                 rec->ExceptionCode = EXCEPTION_VM86_STI;
 853                 break; /* Handle the pending event. */
 854             }
 855             return ExceptionContinueExecution;
 856     }
 857     return ExceptionContinueSearch;  /* Unable to emulate it */
 858 }
 859
 860
 861 /***********************************************************************
 862  *           INSTR_vectored_handler
 863  *
 864  * Vectored exception handler used to emulate protected instructions
 865  * from 32-bit code.
 866  */
 867 LONG CALLBACK INSTR_vectored_handler( EXCEPTION_POINTERS *ptrs )
 868 {
 869     EXCEPTION_RECORD *record = ptrs->ExceptionRecord;
 870     CONTEXT *context = ptrs->ContextRecord;
 871
 872     if (wine_ldt_is_system(context->SegCs) &&
 873         (record->ExceptionCode == EXCEPTION_ACCESS_VIOLATION ||
 874          record->ExceptionCode == EXCEPTION_PRIV_INSTRUCTION))
 875     {
 876         if (__wine_emulate_instruction( record, context ) == ExceptionContinueExecution)
 877             return EXCEPTION_CONTINUE_EXECUTION;
 878     }
 879     return EXCEPTION_CONTINUE_SEARCH;
 880 }
 881
 882
 883 /***********************************************************************
 884  *           DOS3Call         (KERNEL.102)
 885  */
 886 void WINAPI DOS3Call( CONTEXT *context )
 887 {
 888     __wine_call_int_handler( context, 0x21 );
 889 }
 890
 891
 892 /***********************************************************************
 893  *           NetBIOSCall      (KERNEL.103)
 894  */
 895 void WINAPI NetBIOSCall16( CONTEXT *context )
 896 {
 897     __wine_call_int_handler( context, 0x5c );
 898 }
 899
 900
 901 /***********************************************************************
 902  *              GetSetKernelDOSProc (KERNEL.311)
 903  */
 904 FARPROC16 WINAPI GetSetKernelDOSProc16( FARPROC16 DosProc )
 905 {
 906     FIXME("(DosProc=%p): stub\n", DosProc);
 907     return NULL;
 908 }