msdos/dpmi.c

   1 /*
   2  * DPMI 0.9 emulation
   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 "config.h"
  22 #include "wine/port.h"
  23
  24 #include <unistd.h>
  25 #include <string.h>
  26
  27 #include "windef.h"
  28 #include "wine/winbase16.h"
  29 #include "miscemu.h"
  30 #include "msdos.h"
  31 #include "task.h"
  32 #include "toolhelp.h"
  33 #include "selectors.h"
  34 #include "callback.h"
  35 #include "wine/debug.h"
  36 #include "stackframe.h"
  37
  38 WINE_DEFAULT_DEBUG_CHANNEL(int31);
  39
  40 #define DOS_GET_DRIVE(reg) ((reg) ? (reg) - 1 : DRIVE_GetCurrentDrive())
  41
  42 void CreateBPB(int drive, BYTE *data, BOOL16 limited);  /* defined in int21.c */
  43
  44 static void* lastvalloced = NULL;
  45
  46
  47 DOSVM_TABLE Dosvm = { NULL, };
  48
  49 static HMODULE DosModule;
  50
  51 /**********************************************************************
  52  *          DPMI_LoadDosSystem
  53  */
  54 BOOL DPMI_LoadDosSystem(void)
  55 {
  56     if (DosModule) return TRUE;
  57     DosModule = LoadLibraryA( "winedos.dll" );
  58     if (!DosModule) {
  59         ERR("could not load winedos.dll, DOS subsystem unavailable\n");
  60         return FALSE;
  61     }
  62 #define GET_ADDR(func)  Dosvm.func = (void *)GetProcAddress(DosModule, #func);
  63
  64     GET_ADDR(LoadDosExe);
  65     GET_ADDR(CallRMInt);
  66     GET_ADDR(CallRMProc);
  67     GET_ADDR(AllocRMCB);
  68     GET_ADDR(FreeRMCB);
  69     GET_ADDR(RawModeSwitch);
  70     GET_ADDR(SetTimer);
  71     GET_ADDR(GetTimer);
  72     GET_ADDR(inport);
  73     GET_ADDR(outport);
  74     GET_ADDR(ASPIHandler);
  75 #undef GET_ADDR
  76     return TRUE;
  77 }
  78
  79 /**********************************************************************
  80  *          DPMI_xalloc
  81  * special virtualalloc, allocates lineary monoton growing memory.
  82  * (the usual VirtualAlloc does not satisfy that restriction)
  83  */
  84 static LPVOID
  85 DPMI_xalloc(int len) {
  86         LPVOID  ret;
  87         LPVOID  oldlastv = lastvalloced;
  88
  89         if (lastvalloced) {
  90                 int     xflag = 0;
  91                 ret = NULL;
  92                 while (!ret) {
  93                         ret=VirtualAlloc(lastvalloced,len,MEM_COMMIT|MEM_RESERVE,PAGE_EXECUTE_READWRITE);
  94                         if (!ret)
  95                                 lastvalloced = (char *) lastvalloced + 0x10000;
  96                         /* we failed to allocate one in the first round.
  97                          * try non-linear
  98                          */
  99                         if (!xflag && (lastvalloced<oldlastv)) { /* wrapped */
 100                                 FIXME("failed to allocate lineary growing memory (%d bytes), using non-linear growing...\n",len);
 101                                 xflag++;
 102                         }
 103                         /* if we even fail to allocate something in the next
 104                          * round, return NULL
 105                          */
 106                         if ((xflag==1) && (lastvalloced >= oldlastv))
 107                                 xflag++;
 108                         if ((xflag==2) && (lastvalloced < oldlastv)) {
 109                                 FIXME("failed to allocate any memory of %d bytes!\n",len);
 110                                 return NULL;
 111                         }
 112                 }
 113         } else
 114                  ret=VirtualAlloc(NULL,len,MEM_COMMIT|MEM_RESERVE,PAGE_EXECUTE_READWRITE);
 115         lastvalloced = (LPVOID)(((DWORD)ret+len+0xffff)&~0xffff);
 116         return ret;
 117 }
 118
 119 static void
 120 DPMI_xfree(LPVOID ptr) {
 121         VirtualFree(ptr,0,MEM_RELEASE);
 122 }
 123
 124 /* FIXME: perhaps we could grow this mapped area... */
 125 static LPVOID
 126 DPMI_xrealloc(LPVOID ptr,DWORD newsize) {
 127         MEMORY_BASIC_INFORMATION        mbi;
 128         LPVOID                          newptr;
 129
 130         newptr = DPMI_xalloc(newsize);
 131         if (ptr) {
 132                 if (!VirtualQuery(ptr,&mbi,sizeof(mbi))) {
 133                         FIXME("realloc of DPMI_xallocd region %p?\n",ptr);
 134                         return NULL;
 135                 }
 136                 if (mbi.State == MEM_FREE) {
 137                         FIXME("realloc of DPMI_xallocd region %p?\n",ptr);
 138                         return NULL;
 139                 }
 140                 /* We do not shrink allocated memory. most reallocs
 141                  * only do grows anyway
 142                  */
 143                 if (newsize<=mbi.RegionSize)
 144                         return ptr;
 145                 memcpy(newptr,ptr,mbi.RegionSize);
 146                 DPMI_xfree(ptr);
 147         }
 148         return newptr;
 149 }
 150
 151 /**********************************************************************
 152  *          CallRMInt
 153  */
 154 static void CallRMInt( CONTEXT86 *context )
 155 {
 156     if (!Dosvm.CallRMInt && !DPMI_LoadDosSystem())
 157     {
 158         ERR("could not setup real-mode calls\n");
 159         return;
 160     }
 161     Dosvm.CallRMInt( context );
 162 }
 163
 164
 165 static void CallRMProc( CONTEXT86 *context, int iret )
 166 {
 167     if (!Dosvm.CallRMProc && !DPMI_LoadDosSystem())
 168     {
 169         ERR("could not setup real-mode calls\n");
 170         return;
 171     }
 172     Dosvm.CallRMProc( context, iret );
 173 }
 174
 175 static void AllocRMCB( CONTEXT86 *context )
 176 {
 177     if (!Dosvm.AllocRMCB && !DPMI_LoadDosSystem())
 178     {
 179         ERR("could not setup real-mode calls\n");
 180         return;
 181     }
 182     Dosvm.AllocRMCB( context );
 183 }
 184
 185 static void FreeRMCB( CONTEXT86 *context )
 186 {
 187     if (!Dosvm.FreeRMCB)  /* cannot have allocated one if dosvm not loaded */
 188     {
 189         SET_LOWORD( context->Eax, 0x8024 ); /* invalid callback address */
 190         SET_CFLAG( context );
 191     }
 192     else Dosvm.FreeRMCB( context );
 193 }
 194
 195 static void RawModeSwitch( CONTEXT86 *context )
 196 {
 197     if (!Dosvm.RawModeSwitch)
 198     {
 199       ERR("could not setup real-mode calls\n");
 200       return;
 201     }
 202     else
 203     {
 204       /*
 205        * FIXME: This routine will not work if it is called
 206        *        from 32 bit DPMI program and the program returns
 207        *        to protected mode while ESP or EIP is over 0xffff.
 208        * FIXME: This routine will not work if it is not called
 209        *        using 16-bit-to-Wine callback glue function.
 210        */
 211       STACK16FRAME frame = *CURRENT_STACK16;
 212
 213       Dosvm.RawModeSwitch( context );
 214
 215       /*
 216        * After this function returns to relay code, protected mode
 217        * 16 bit stack will contain STACK16FRAME and single WORD
 218        * (EFlags, see next comment).
 219        */
 220       NtCurrentTeb()->cur_stack =
 221         MAKESEGPTR( context->SegSs,
 222                     context->Esp - sizeof(STACK16FRAME) - sizeof(WORD) );
 223
 224       /*
 225        * After relay code returns to glue function, protected
 226        * mode 16 bit stack will contain interrupt return record:
 227        * IP, CS and EFlags. Since EFlags is ignored, it won't
 228        * need to be initialized.
 229        */
 230       context->Esp -= 3 * sizeof(WORD);
 231
 232       /*
 233        * Restore stack frame so that relay code won't be confused.
 234        * It should be noted that relay code overwrites IP and CS
 235        * in STACK16FRAME with values taken from current CONTEXT86.
 236        * These values are what is returned to glue function
 237        * (see previous comment).
 238        */
 239       *CURRENT_STACK16 = frame;
 240     }
 241 }
 242
 243 /**********************************************************************
 244  *          INT_Int31Handler (WPROCS.149)
 245  *
 246  * Handler for int 31h (DPMI).
 247  */
 248
 249 void WINAPI INT_Int31Handler( CONTEXT86 *context )
 250 {
 251     /*
 252      * Note: For Win32s processes, the whole linear address space is
 253      *       shifted by 0x10000 relative to the OS linear address space.
 254      *       See the comment in msdos/vxd.c.
 255      */
 256     DWORD dw;
 257     BYTE *ptr;
 258
 259     if (context->SegCs == DOSMEM_dpmi_sel) {
 260         RawModeSwitch( context );
 261         return;
 262     }
 263
 264     RESET_CFLAG(context);
 265     switch(AX_reg(context))
 266     {
 267     case 0x0000:  /* Allocate LDT descriptors */
 268         TRACE("allocate LDT descriptors (%d)\n",CX_reg(context));
 269         if (!(context->Eax = AllocSelectorArray16( CX_reg(context) )))
 270         {
 271             TRACE("failed\n");
 272             context->Eax = 0x8011;  /* descriptor unavailable */
 273             SET_CFLAG(context);
 274         }
 275         TRACE("success, array starts at 0x%04x\n",AX_reg(context));
 276         break;
 277
 278     case 0x0001:  /* Free LDT descriptor */
 279         TRACE("free LDT descriptor (0x%04x)\n",BX_reg(context));
 280         if (FreeSelector16( BX_reg(context) ))
 281         {
 282             context->Eax = 0x8022;  /* invalid selector */
 283             SET_CFLAG(context);
 284         }
 285         else
 286         {
 287             /* If a segment register contains the selector being freed, */
 288             /* set it to zero. */
 289             if (!((context->SegDs^BX_reg(context)) & ~3)) context->SegDs = 0;
 290             if (!((context->SegEs^BX_reg(context)) & ~3)) context->SegEs = 0;
 291             if (!((context->SegFs^BX_reg(context)) & ~3)) context->SegFs = 0;
 292             if (!((context->SegGs^BX_reg(context)) & ~3)) context->SegGs = 0;
 293         }
 294         break;
 295
 296     case 0x0002:  /* Real mode segment to descriptor */
 297         TRACE("real mode segment to descriptor (0x%04x)\n",BX_reg(context));
 298         {
 299             WORD entryPoint = 0;  /* KERNEL entry point for descriptor */
 300             switch(BX_reg(context))
 301             {
 302             case 0x0000: entryPoint = 183; break;  /* __0000H */
 303             case 0x0040: entryPoint = 193; break;  /* __0040H */
 304             case 0xa000: entryPoint = 174; break;  /* __A000H */
 305             case 0xb000: entryPoint = 181; break;  /* __B000H */
 306             case 0xb800: entryPoint = 182; break;  /* __B800H */
 307             case 0xc000: entryPoint = 195; break;  /* __C000H */
 308             case 0xd000: entryPoint = 179; break;  /* __D000H */
 309             case 0xe000: entryPoint = 190; break;  /* __E000H */
 310             case 0xf000: entryPoint = 194; break;  /* __F000H */
 311             default:
 312                 context->Eax = DOSMEM_AllocSelector(BX_reg(context));
 313                 break;
 314             }
 315             if (entryPoint)
 316                 context->Eax = LOWORD(GetProcAddress16( GetModuleHandle16( "KERNEL" ),
 317                                                         (LPCSTR)(ULONG_PTR)entryPoint ));
 318         }
 319         break;
 320
 321     case 0x0003:  /* Get next selector increment */
 322         TRACE("get selector increment (__AHINCR)\n");
 323         context->Eax = __AHINCR;
 324         break;
 325
 326     case 0x0004:  /* Lock selector (not supported) */
 327         FIXME("lock selector not supported\n");
 328         context->Eax = 0;  /* FIXME: is this a correct return value? */
 329         break;
 330
 331     case 0x0005:  /* Unlock selector (not supported) */
 332         FIXME("unlock selector not supported\n");
 333         context->Eax = 0;  /* FIXME: is this a correct return value? */
 334         break;
 335
 336     case 0x0006:  /* Get selector base address */
 337         TRACE("get selector base address (0x%04x)\n",BX_reg(context));
 338         if (!(dw = GetSelectorBase( BX_reg(context) )))
 339         {
 340             context->Eax = 0x8022;  /* invalid selector */
 341             SET_CFLAG(context);
 342         }
 343         else
 344         {
 345             CX_reg(context) = HIWORD(W32S_WINE2APP(dw));
 346             DX_reg(context) = LOWORD(W32S_WINE2APP(dw));
 347         }
 348         break;
 349
 350     case 0x0007:  /* Set selector base address */
 351         TRACE("set selector base address (0x%04x,0x%08lx)\n",
 352                      BX_reg(context),
 353                      W32S_APP2WINE(MAKELONG(DX_reg(context),CX_reg(context))));
 354         dw = W32S_APP2WINE(MAKELONG(DX_reg(context), CX_reg(context)));
 355         if (dw < 0x10000)
 356             /* app wants to access lower 64K of DOS memory, load DOS subsystem */
 357             DPMI_LoadDosSystem();
 358         SetSelectorBase(BX_reg(context), dw);
 359         break;
 360
 361     case 0x0008:  /* Set selector limit */
 362         TRACE("set selector limit (0x%04x,0x%08lx)\n",BX_reg(context),MAKELONG(DX_reg(context),CX_reg(context)));
 363         dw = MAKELONG( DX_reg(context), CX_reg(context) );
 364         SetSelectorLimit16( BX_reg(context), dw );
 365         break;
 366
 367     case 0x0009:  /* Set selector access rights */
 368         TRACE("set selector access rights(0x%04x,0x%04x)\n",BX_reg(context),CX_reg(context));
 369         SelectorAccessRights16( BX_reg(context), 1, CX_reg(context) );
 370         break;
 371
 372     case 0x000a:  /* Allocate selector alias */
 373         TRACE("allocate selector alias (0x%04x)\n",BX_reg(context));
 374         if (!(AX_reg(context) = AllocCStoDSAlias16( BX_reg(context) )))
 375         {
 376             AX_reg(context) = 0x8011;  /* descriptor unavailable */
 377             SET_CFLAG(context);
 378         }
 379         break;
 380
 381     case 0x000b:  /* Get descriptor */
 382         TRACE("get descriptor (0x%04x)\n",BX_reg(context));
 383         {
 384             LDT_ENTRY entry;
 385             wine_ldt_set_base( &entry, (void*)W32S_WINE2APP(wine_ldt_get_base(&entry)) );
 386             /* FIXME: should use ES:EDI for 32-bit clients */
 387             *(LDT_ENTRY *)MapSL( MAKESEGPTR( context->SegEs, LOWORD(context->Edi) )) = entry;
 388         }
 389         break;
 390
 391     case 0x000c:  /* Set descriptor */
 392         TRACE("set descriptor (0x%04x)\n",BX_reg(context));
 393         {
 394             LDT_ENTRY entry = *(LDT_ENTRY *)MapSL(MAKESEGPTR( context->SegEs, LOWORD(context->Edi)));
 395             wine_ldt_set_base( &entry, (void*)W32S_APP2WINE(wine_ldt_get_base(&entry)) );
 396             wine_ldt_set_entry( LOWORD(context->Ebx), &entry );
 397         }
 398         break;
 399
 400     case 0x000d:  /* Allocate specific LDT descriptor */
 401         FIXME("allocate descriptor (0x%04x), stub!\n",BX_reg(context));
 402         AX_reg(context) = 0x8011; /* descriptor unavailable */
 403         SET_CFLAG(context);
 404         break;
 405     case 0x0100:  /* Allocate DOS memory block */
 406         TRACE("allocate DOS memory block (0x%x paragraphs)\n",BX_reg(context));
 407         dw = GlobalDOSAlloc16((DWORD)BX_reg(context)<<4);
 408         if (dw) {
 409             AX_reg(context) = HIWORD(dw);
 410             DX_reg(context) = LOWORD(dw);
 411         } else {
 412             AX_reg(context) = 0x0008; /* insufficient memory */
 413             BX_reg(context) = DOSMEM_Available()>>4;
 414             SET_CFLAG(context);
 415         }
 416         break;
 417     case 0x0101:  /* Free DOS memory block */
 418         TRACE("free DOS memory block (0x%04x)\n",DX_reg(context));
 419         dw = GlobalDOSFree16(DX_reg(context));
 420         if (!dw) {
 421             AX_reg(context) = 0x0009; /* memory block address invalid */
 422             SET_CFLAG(context);
 423         }
 424         break;
 425     case 0x0200: /* get real mode interrupt vector */
 426         FIXME("get realmode interupt vector(0x%02x) unimplemented.\n",
 427               BL_reg(context));
 428         SET_CFLAG(context);
 429         break;
 430     case 0x0201: /* set real mode interrupt vector */
 431         FIXME("set realmode interrupt vector(0x%02x,0x%04x:0x%04x) unimplemented\n", BL_reg(context),CX_reg(context),DX_reg(context));
 432         SET_CFLAG(context);
 433         break;
 434     case 0x0204:  /* Get protected mode interrupt vector */
 435         TRACE("get protected mode interrupt handler (0x%02x), stub!\n",BL_reg(context));
 436         dw = (DWORD)INT_GetPMHandler( BL_reg(context) );
 437         CX_reg(context) = HIWORD(dw);
 438         DX_reg(context) = LOWORD(dw);
 439         break;
 440
 441     case 0x0205:  /* Set protected mode interrupt vector */
 442         TRACE("set protected mode interrupt handler (0x%02x,%p), stub!\n",
 443             BL_reg(context),MapSL(MAKESEGPTR(CX_reg(context),DX_reg(context))));
 444         INT_SetPMHandler( BL_reg(context),
 445                           (FARPROC16)MAKESEGPTR( CX_reg(context), DX_reg(context) ));
 446         break;
 447
 448     case 0x0300:  /* Simulate real mode interrupt */
 449         CallRMInt( context );
 450         break;
 451
 452     case 0x0301:  /* Call real mode procedure with far return */
 453         CallRMProc( context, FALSE );
 454         break;
 455
 456     case 0x0302:  /* Call real mode procedure with interrupt return */
 457         CallRMProc( context, TRUE );
 458         break;
 459
 460     case 0x0303:  /* Allocate Real Mode Callback Address */
 461         AllocRMCB( context );
 462         break;
 463
 464     case 0x0304:  /* Free Real Mode Callback Address */
 465         FreeRMCB( context );
 466         break;
 467
 468     case 0x0305:  /* Get State Save/Restore Addresses */
 469         TRACE("get state save/restore addresses\n");
 470         /* we probably won't need this kind of state saving */
 471         AX_reg(context) = 0;
 472         /* real mode: just point to the lret */
 473         BX_reg(context) = DOSMEM_wrap_seg;
 474         context->Ecx = 2;
 475         /* protected mode: don't have any handler yet... */
 476         FIXME("no protected-mode dummy state save/restore handler yet\n");
 477         SI_reg(context) = 0;
 478         context->Edi = 0;
 479         break;
 480
 481     case 0x0306:  /* Get Raw Mode Switch Addresses */
 482         TRACE("get raw mode switch addresses\n");
 483         /* real mode, point to standard DPMI return wrapper */
 484         BX_reg(context) = DOSMEM_wrap_seg;
 485         context->Ecx = 0;
 486         /* protected mode, point to DPMI call wrapper */
 487         SI_reg(context) = DOSMEM_dpmi_sel;
 488         context->Edi = 8; /* offset of the INT 0x31 call */
 489         break;
 490     case 0x0400:  /* Get DPMI version */
 491         TRACE("get DPMI version\n");
 492         {
 493             SYSTEM_INFO si;
 494
 495             GetSystemInfo(&si);
 496             AX_reg(context) = 0x005a;  /* DPMI version 0.90 */
 497             BX_reg(context) = 0x0005;  /* Flags: 32-bit, virtual memory */
 498             CL_reg(context) = si.wProcessorLevel;
 499             DX_reg(context) = 0x0102;  /* Master/slave interrupt controller base*/
 500             break;
 501         }
 502     case 0x0500:  /* Get free memory information */
 503         TRACE("get free memory information\n");
 504         {
 505             MEMMANINFO mmi;
 506
 507             mmi.dwSize = sizeof(mmi);
 508             MemManInfo16(&mmi);
 509             ptr = MapSL(MAKESEGPTR(context->SegEs,DI_reg(context)));
 510             /* the layout is just the same as MEMMANINFO, but without
 511              * the dwSize entry.
 512              */
 513             memcpy(ptr,((char*)&mmi)+4,sizeof(mmi)-4);
 514             break;
 515         }
 516     case 0x0501:  /* Allocate memory block */
 517         TRACE("allocate memory block (%ld)\n",MAKELONG(CX_reg(context),BX_reg(context)));
 518         if (!(ptr = (BYTE *)DPMI_xalloc(MAKELONG(CX_reg(context), BX_reg(context)))))
 519         {
 520             AX_reg(context) = 0x8012;  /* linear memory not available */
 521             SET_CFLAG(context);
 522         } else {
 523             BX_reg(context) = SI_reg(context) = HIWORD(W32S_WINE2APP(ptr));
 524             CX_reg(context) = DI_reg(context) = LOWORD(W32S_WINE2APP(ptr));
 525         }
 526         break;
 527
 528     case 0x0502:  /* Free memory block */
 529         TRACE("free memory block (0x%08lx)\n",
 530                      W32S_APP2WINE(MAKELONG(DI_reg(context),SI_reg(context))));
 531         DPMI_xfree( (void *)W32S_APP2WINE(MAKELONG(DI_reg(context), SI_reg(context))) );
 532         break;
 533
 534     case 0x0503:  /* Resize memory block */
 535         TRACE("resize memory block (0x%08lx,%ld)\n",
 536                      W32S_APP2WINE(MAKELONG(DI_reg(context),SI_reg(context))),
 537                      MAKELONG(CX_reg(context),BX_reg(context)));
 538         if (!(ptr = (BYTE *)DPMI_xrealloc(
 539                 (void *)W32S_APP2WINE(MAKELONG(DI_reg(context),SI_reg(context))),
 540                 MAKELONG(CX_reg(context),BX_reg(context)))))
 541         {
 542             AX_reg(context) = 0x8012;  /* linear memory not available */
 543             SET_CFLAG(context);
 544         } else {
 545             BX_reg(context) = SI_reg(context) = HIWORD(W32S_WINE2APP(ptr));
 546             CX_reg(context) = DI_reg(context) = LOWORD(W32S_WINE2APP(ptr));
 547         }
 548         break;
 549
 550     case 0x0507:  /* Modify page attributes */
 551         FIXME("modify page attributes unimplemented\n");
 552         break;  /* Just ignore it */
 553
 554     case 0x0600:  /* Lock linear region */
 555         FIXME("lock linear region unimplemented\n");
 556         break;  /* Just ignore it */
 557
 558     case 0x0601:  /* Unlock linear region */
 559         FIXME("unlock linear region unimplemented\n");
 560         break;  /* Just ignore it */
 561
 562     case 0x0602:  /* Unlock real-mode region */
 563         FIXME("unlock realmode region unimplemented\n");
 564         break;  /* Just ignore it */
 565
 566     case 0x0603:  /* Lock real-mode region */
 567         FIXME("lock realmode region unimplemented\n");
 568         break;  /* Just ignore it */
 569
 570     case 0x0604:  /* Get page size */
 571         TRACE("get pagesize\n");
 572         BX_reg(context) = 0;
 573         CX_reg(context) = getpagesize();
 574         break;
 575
 576     case 0x0702:  /* Mark page as demand-paging candidate */
 577         FIXME("mark page as demand-paging candidate\n");
 578         break;  /* Just ignore it */
 579
 580     case 0x0703:  /* Discard page contents */
 581         FIXME("discard page contents\n");
 582         break;  /* Just ignore it */
 583
 584      case 0x0800:  /* Physical address mapping */
 585         FIXME("map real to linear (0x%08lx)\n",MAKELONG(CX_reg(context),BX_reg(context)));
 586          if(!(ptr=DOSMEM_MapRealToLinear(MAKELONG(CX_reg(context),BX_reg(context)))))
 587          {
 588              AX_reg(context) = 0x8021;
 589              SET_CFLAG(context);
 590          }
 591          else
 592          {
 593              BX_reg(context) = HIWORD(W32S_WINE2APP(ptr));
 594              CX_reg(context) = LOWORD(W32S_WINE2APP(ptr));
 595              RESET_CFLAG(context);
 596          }
 597          break;
 598
 599     default:
 600         INT_BARF( context, 0x31 );
 601         AX_reg(context) = 0x8001;  /* unsupported function */
 602         SET_CFLAG(context);
 603         break;
 604     }
 605
 606 }