msdos/dosmem.c

   1 /*
   2  * DOS memory emulation
   3  *
   4  * Copyright 1995 Alexandre Julliard
   5  * Copyright 1996 Marcus Meissner
   6  */
   7
   8 #include "config.h"
   9
  10 #include <signal.h>
  11 #include <stdlib.h>
  12 #include <string.h>
  13 #include <sys/types.h>
  14 #ifdef HAVE_SYS_MMAN_H
  15 # include <sys/mman.h>
  16 #endif
  17
  18 #include "winbase.h"
  19 #include "wine/winbase16.h"
  20 #include "wine/port.h"
  21
  22 #include "global.h"
  23 #include "selectors.h"
  24 #include "miscemu.h"
  25 #include "vga.h"
  26 #include "dosexe.h"
  27 #include "debugtools.h"
  28
  29 DEFAULT_DEBUG_CHANNEL(dosmem);
  30 DECLARE_DEBUG_CHANNEL(selector);
  31
  32 WORD DOSMEM_0000H;        /* segment at 0:0 */
  33 WORD DOSMEM_BiosDataSeg;  /* BIOS data segment at 0x40:0 */
  34 WORD DOSMEM_BiosSysSeg;   /* BIOS ROM segment at 0xf000:0 */
  35
  36 DWORD DOSMEM_CollateTable;
  37
  38 /* use 2 low bits of 'size' for the housekeeping */
  39
  40 #define DM_BLOCK_DEBUG          0xABE00000
  41 #define DM_BLOCK_TERMINAL       0x00000001
  42 #define DM_BLOCK_FREE           0x00000002
  43 #define DM_BLOCK_MASK           0x001FFFFC
  44
  45 /*
  46 #define __DOSMEM_DEBUG__
  47  */
  48
  49 typedef struct {
  50    unsigned     size;
  51 } dosmem_entry;
  52
  53 typedef struct {
  54   unsigned      blocks;
  55   unsigned      free;
  56 } dosmem_info;
  57
  58 #define NEXT_BLOCK(block) \
  59         (dosmem_entry*)(((char*)(block)) + \
  60          sizeof(dosmem_entry) + ((block)->size & DM_BLOCK_MASK))
  61
  62 #define VM_STUB(x) (0x90CF00CD|(x<<8)) /* INT x; IRET; NOP */
  63 #define VM_STUB_SEGMENT 0xf000         /* BIOS segment */
  64
  65 /* DOS memory base */
  66 static char *DOSMEM_dosmem;
  67 /* DOS system base (for interrupt vector table and BIOS data area)
  68  * ...should in theory (i.e. Windows) be equal to DOSMEM_dosmem (NULL),
  69  * but is normally set to 0xf0000 in Wine to allow trapping of NULL pointers,
  70  * and only relocated to NULL when absolutely necessary */
  71 static char *DOSMEM_sysmem;
  72
  73 /* various real-mode code stubs */
  74 WORD DOSMEM_wrap_seg;
  75 WORD DOSMEM_xms_seg;
  76 WORD DOSMEM_dpmi_seg;
  77 WORD DOSMEM_dpmi_sel;
  78
  79 /***********************************************************************
  80  *           DOSMEM_SystemBase
  81  *
  82  * Gets the virtual DOS memory base (interrupt table).
  83  */
  84 char *DOSMEM_SystemBase(void)
  85 {
  86     return DOSMEM_sysmem;
  87 }
  88
  89 /***********************************************************************
  90  *           DOSMEM_MemoryBase
  91  *
  92  * Gets the DOS memory base.
  93  */
  94 char *DOSMEM_MemoryBase(void)
  95 {
  96     return DOSMEM_dosmem;
  97 }
  98
  99 /***********************************************************************
 100  *           DOSMEM_MemoryTop
 101  *
 102  * Gets the DOS memory top.
 103  */
 104 static char *DOSMEM_MemoryTop(void)
 105 {
 106     return DOSMEM_dosmem+0x9FFFC; /* 640K */
 107 }
 108
 109 /***********************************************************************
 110  *           DOSMEM_InfoBlock
 111  *
 112  * Gets the DOS memory info block.
 113  */
 114 static dosmem_info *DOSMEM_InfoBlock(void)
 115 {
 116     return (dosmem_info*)(DOSMEM_dosmem+0x10000); /* 64K */
 117 }
 118
 119 /***********************************************************************
 120  *           DOSMEM_RootBlock
 121  *
 122  * Gets the DOS memory root block.
 123  */
 124 static dosmem_entry *DOSMEM_RootBlock(void)
 125 {
 126     /* first block has to be paragraph-aligned */
 127     return (dosmem_entry*)(((char*)DOSMEM_InfoBlock()) +
 128                            ((((sizeof(dosmem_info) + 0xf) & ~0xf) - sizeof(dosmem_entry))));
 129 }
 130
 131 /***********************************************************************
 132  *           DOSMEM_FillIsrTable
 133  *
 134  * Fill the interrupt table with fake BIOS calls to BIOSSEG (0xf000).
 135  *
 136  * NOTES:
 137  * Linux normally only traps INTs performed from or destined to BIOSSEG
 138  * for us to handle, if the int_revectored table is empty. Filling the
 139  * interrupt table with calls to INT stubs in BIOSSEG allows DOS programs
 140  * to hook interrupts, as well as use their familiar retf tricks to call
 141  * them, AND let Wine handle any unhooked interrupts transparently.
 142  */
 143 static void DOSMEM_FillIsrTable(void)
 144 {
 145     SEGPTR *isr = (SEGPTR*)DOSMEM_sysmem;
 146     int x;
 147
 148     for (x=0; x<256; x++) isr[x]=MAKESEGPTR(VM_STUB_SEGMENT,x*4);
 149 }
 150
 151 static void DOSMEM_MakeIsrStubs(void)
 152 {
 153     DWORD *stub = (DWORD*)(DOSMEM_dosmem + (VM_STUB_SEGMENT << 4));
 154     int x;
 155
 156     for (x=0; x<256; x++) stub[x]=VM_STUB(x);
 157 }
 158
 159 /***********************************************************************
 160  *           DOSMEM_InitDPMI
 161  *
 162  * Allocate the global DPMI RMCB wrapper.
 163  */
 164 static void DOSMEM_InitDPMI(void)
 165 {
 166     LPSTR ptr;
 167
 168     static const char wrap_code[]={
 169      0xCD,0x31, /* int $0x31 */
 170      0xCB       /* lret */
 171     };
 172
 173     static const char enter_xms[]=
 174     {
 175         /* XMS hookable entry point */
 176         0xEB,0x03,           /* jmp entry */
 177         0x90,0x90,0x90,      /* nop;nop;nop */
 178                              /* entry: */
 179         /* real entry point */
 180         /* for simplicity, we'll just use the same hook as DPMI below */
 181         0xCD,0x31,           /* int $0x31 */
 182         0xCB                 /* lret */
 183     };
 184
 185     static const char enter_pm[]=
 186     {
 187         0x50,                /* pushw %ax */
 188         0x52,                /* pushw %dx */
 189         0x55,                /* pushw %bp */
 190         0x89,0xE5,           /* movw %sp,%bp */
 191         /* get return CS */
 192         0x8B,0x56,0x08,      /* movw 8(%bp),%dx */
 193         /* just call int 31 here to get into protected mode... */
 194         /* it'll check whether it was called from dpmi_seg... */
 195         0xCD,0x31,           /* int $0x31 */
 196         /* we are now in the context of a 16-bit relay call */
 197         /* need to fixup our stack;
 198          * 16-bit relay return address will be lost, but we won't worry quite yet */
 199         0x8E,0xD0,           /* movw %ax,%ss */
 200         0x66,0x0F,0xB7,0xE5, /* movzwl %bp,%esp */
 201         /* set return CS */
 202         0x89,0x56,0x08,      /* movw %dx,8(%bp) */
 203         0x5D,                /* popw %bp */
 204         0x5A,                /* popw %dx */
 205         0x58,                /* popw %ax */
 206         0xCB                 /* lret */
 207     };
 208
 209     ptr = DOSMEM_GetBlock( sizeof(wrap_code), &DOSMEM_wrap_seg );
 210     memcpy( ptr, wrap_code, sizeof(wrap_code) );
 211     ptr = DOSMEM_GetBlock( sizeof(enter_xms), &DOSMEM_xms_seg );
 212     memcpy( ptr, enter_xms, sizeof(enter_xms) );
 213     ptr = DOSMEM_GetBlock( sizeof(enter_pm), &DOSMEM_dpmi_seg );
 214     memcpy( ptr, enter_pm, sizeof(enter_pm) );
 215     DOSMEM_dpmi_sel = SELECTOR_AllocBlock( ptr, sizeof(enter_pm), WINE_LDT_FLAGS_CODE );
 216 }
 217
 218 BIOSDATA * DOSMEM_BiosData()
 219 {
 220     return (BIOSDATA *)(DOSMEM_sysmem + 0x400);
 221 }
 222
 223 BYTE * DOSMEM_BiosSys()
 224 {
 225     return DOSMEM_dosmem+0xf0000;
 226 }
 227
 228 struct _DOS_LISTOFLISTS * DOSMEM_LOL()
 229 {
 230     return (struct _DOS_LISTOFLISTS *)DOSMEM_MapRealToLinear
 231       (MAKESEGPTR(HIWORD(DOS_LOLSeg),0));
 232 }
 233
 234 /***********************************************************************
 235  *           DOSMEM_FillBiosSegments
 236  *
 237  * Fill the BIOS data segment with dummy values.
 238  */
 239 static void DOSMEM_FillBiosSegments(void)
 240 {
 241     BYTE *pBiosSys = DOSMEM_BiosSys();
 242     BYTE *pBiosROMTable = pBiosSys+0xe6f5;
 243     BIOSDATA *pBiosData = DOSMEM_BiosData();
 244
 245     /* bogus 0xe0xx addresses !! Adapt int 0x10/0x1b if change needed */
 246     VIDEOFUNCTIONALITY *pVidFunc = (VIDEOFUNCTIONALITY *)(pBiosSys+0xe000);
 247     VIDEOSTATE *pVidState = (VIDEOSTATE *)(pBiosSys+0xe010);
 248     int i;
 249
 250       /* Clear all unused values */
 251     memset( pBiosData, 0, sizeof(*pBiosData) );
 252     memset( pVidFunc,  0, sizeof(*pVidFunc ) );
 253     memset( pVidState, 0, sizeof(*pVidState) );
 254
 255     /* FIXME: should check the number of configured drives and ports */
 256
 257     pBiosData->Com1Addr             = 0x3f8;
 258     pBiosData->Com2Addr             = 0x2f8;
 259     pBiosData->Lpt1Addr             = 0x378;
 260     pBiosData->Lpt2Addr             = 0x278;
 261     pBiosData->InstalledHardware    = 0x5463;
 262     pBiosData->MemSize              = 640;
 263     pBiosData->NextKbdCharPtr       = 0x1e;
 264     pBiosData->FirstKbdCharPtr      = 0x1e;
 265     pBiosData->VideoMode            = 3;
 266     pBiosData->VideoColumns         = 80;
 267     pBiosData->VideoPageSize        = 80 * 25 * 2;
 268     pBiosData->VideoPageStartAddr   = 0xb800;
 269     pBiosData->VideoCtrlAddr        = 0x3d4;
 270     pBiosData->Ticks                = INT1A_GetTicksSinceMidnight();
 271     pBiosData->NbHardDisks          = 2;
 272     pBiosData->KbdBufferStart       = 0x1e;
 273     pBiosData->KbdBufferEnd         = 0x3e;
 274     pBiosData->RowsOnScreenMinus1   = 23;
 275     pBiosData->BytesPerChar         = 0x10;
 276     pBiosData->ModeOptions          = 0x64;
 277     pBiosData->FeatureBitsSwitches  = 0xf9;
 278     pBiosData->VGASettings          = 0x51;
 279     pBiosData->DisplayCombination   = 0x08;
 280     pBiosData->DiskDataRate         = 0;
 281
 282     /* fill ROM configuration table (values from Award) */
 283     *(pBiosROMTable+0x0)        = 0x08; /* number of bytes following LO */
 284     *(pBiosROMTable+0x1)        = 0x00; /* number of bytes following HI */
 285     *(pBiosROMTable+0x2)        = 0xfc; /* model */
 286     *(pBiosROMTable+0x3)        = 0x01; /* submodel */
 287     *(pBiosROMTable+0x4)        = 0x00; /* BIOS revision */
 288     *(pBiosROMTable+0x5)        = 0x74; /* feature byte 1 */
 289     *(pBiosROMTable+0x6)        = 0x00; /* feature byte 2 */
 290     *(pBiosROMTable+0x7)        = 0x00; /* feature byte 3 */
 291     *(pBiosROMTable+0x8)        = 0x00; /* feature byte 4 */
 292     *(pBiosROMTable+0x9)        = 0x00; /* feature byte 5 */
 293
 294
 295     for (i = 0; i < 7; i++)
 296         pVidFunc->ModeSupport[i] = 0xff;
 297
 298     pVidFunc->ScanlineSupport     = 7;
 299     pVidFunc->NumberCharBlocks    = 0;
 300     pVidFunc->ActiveCharBlocks    = 0;
 301     pVidFunc->MiscFlags           = 0x8ff;
 302     pVidFunc->SavePointerFlags    = 0x3f;
 303
 304     pVidState->StaticFuncTable    = 0xf000e000;  /* FIXME: always real mode ? */
 305     pVidState->VideoMode          = pBiosData->VideoMode; /* needs updates! */
 306     pVidState->NumberColumns      = pBiosData->VideoColumns; /* needs updates! */
 307     pVidState->RegenBufLen        = 0;
 308     pVidState->RegenBufAddr       = 0;
 309
 310     for (i = 0; i < 8; i++)
 311         pVidState->CursorPos[i] = 0;
 312
 313     pVidState->CursorType         = 0x0a0b;  /* start/end line */
 314     pVidState->ActivePage         = 0;
 315     pVidState->CRTCPort           = 0x3da;
 316     pVidState->Port3x8            = 0;
 317     pVidState->Port3x9            = 0;
 318     pVidState->NumberRows         = 23;     /* number of rows - 1 */
 319     pVidState->BytesPerChar       = 0x10;
 320     pVidState->DCCActive          = pBiosData->DisplayCombination;
 321     pVidState->DCCAlternate       = 0;
 322     pVidState->NumberColors       = 16;
 323     pVidState->NumberPages        = 1;
 324     pVidState->NumberScanlines    = 3; /* (0,1,2,3) = (200,350,400,480) */
 325     pVidState->CharBlockPrimary   = 0;
 326     pVidState->CharBlockSecondary = 0;
 327     pVidState->MiscFlags =
 328                            (pBiosData->VGASettings & 0x0f)
 329                          | ((pBiosData->ModeOptions & 1) << 4); /* cursor emulation */
 330     pVidState->NonVGASupport      = 0;
 331     pVidState->VideoMem           = (pBiosData->ModeOptions & 0x60 >> 5);
 332     pVidState->SavePointerState   = 0;
 333     pVidState->DisplayStatus      = 4;
 334
 335     /* BIOS date string */
 336     strcpy((char *)pBiosSys+0xfff5, "13/01/99");
 337
 338     /* BIOS ID */
 339     *(pBiosSys+0xfffe) = 0xfc;
 340 }
 341
 342 /***********************************************************************
 343  *           DOSMEM_InitCollateTable
 344  *
 345  * Initialises the collate table (character sorting, language dependent)
 346  */
 347 static void DOSMEM_InitCollateTable()
 348 {
 349         DWORD           x;
 350         unsigned char   *tbl;
 351         int             i;
 352
 353         x = GlobalDOSAlloc16(258);
 354         DOSMEM_CollateTable = MAKELONG(0,(x>>16));
 355         tbl = DOSMEM_MapRealToLinear(DOSMEM_CollateTable);
 356         *(WORD*)tbl     = 0x100;
 357         tbl += 2;
 358         for ( i = 0; i < 0x100; i++) *tbl++ = i;
 359 }
 360
 361 /***********************************************************************
 362  *           DOSMEM_InitErrorTable
 363  *
 364  * Initialises the error tables (DOS 5+)
 365  */
 366 static void DOSMEM_InitErrorTable()
 367 {
 368 #if 0  /* no longer used */
 369         DWORD           x;
 370         char            *call;
 371
 372         /* We will use a snippet of real mode code that calls */
 373         /* a WINE-only interrupt to handle moving the requested */
 374         /* message into the buffer... */
 375
 376         /* FIXME - There is still something wrong... */
 377
 378         /* FIXME - Find hex values for opcodes...
 379
 380            (On call, AX contains message number
 381                      DI contains 'offset' (??)
 382             Resturn, ES:DI points to counted string )
 383
 384            PUSH BX
 385            MOV BX, AX
 386            MOV AX, (arbitrary subfunction number)
 387            INT (WINE-only interrupt)
 388            POP BX
 389            RET
 390
 391         */
 392
 393         const int       code = 4;
 394         const int       buffer = 80;
 395         const int       SIZE_TO_ALLOCATE = code + buffer;
 396
 397         /* FIXME - Complete rewrite of the table system to save */
 398         /* precious DOS space. Now, we return the 0001:???? as */
 399         /* DOS 4+ (??, it seems to be the case in MS 7.10) treats that */
 400         /* as a special case and programs will use the alternate */
 401         /* interface (a farcall returned with INT 24 (AX = 0x122e, DL = */
 402         /* 0x08) which lets us have a smaller memory footprint anyway. */
 403
 404         x = GlobalDOSAlloc16(SIZE_TO_ALLOCATE);
 405
 406         DOSMEM_ErrorCall = MAKELONG(0,(x>>16));
 407         DOSMEM_ErrorBuffer = DOSMEM_ErrorCall + code;
 408
 409         call = DOSMEM_MapRealToLinear(DOSMEM_ErrorCall);
 410
 411         memset(call, 0, SIZE_TO_ALLOCATE);
 412 #endif
 413         /* Fixme - Copy assembly into buffer here */
 414 }
 415
 416 /***********************************************************************
 417  *           DOSMEM_InitMemory
 418  *
 419  * Initialises the DOS memory structures.
 420  */
 421 static void DOSMEM_InitMemory(void)
 422 {
 423    /* Low 64Kb are reserved for DOS/BIOS so the useable area starts at
 424     * 1000:0000 and ends at 9FFF:FFEF. */
 425
 426     dosmem_info*        info_block = DOSMEM_InfoBlock();
 427     dosmem_entry*       root_block = DOSMEM_RootBlock();
 428     dosmem_entry*       dm;
 429
 430     root_block->size = DOSMEM_MemoryTop() - (((char*)root_block) + sizeof(dosmem_entry));
 431
 432     info_block->blocks = 0;
 433     info_block->free = root_block->size;
 434
 435     dm = NEXT_BLOCK(root_block);
 436     dm->size = DM_BLOCK_TERMINAL;
 437     root_block->size |= DM_BLOCK_FREE
 438 #ifdef __DOSMEM_DEBUG__
 439                      | DM_BLOCK_DEBUG
 440 #endif
 441                      ;
 442 }
 443
 444 /**********************************************************************
 445  *              setup_dos_mem
 446  *
 447  * Setup the first megabyte for DOS memory access
 448  */
 449 static void setup_dos_mem( int dos_init )
 450 {
 451     int sys_offset = 0;
 452     int page_size = getpagesize();
 453     void *addr = wine_anon_mmap( (void *)page_size, 0x110000-page_size,
 454                                  PROT_READ | PROT_WRITE | PROT_EXEC, 0 );
 455     if (addr == (void *)page_size)  /* we got what we wanted */
 456     {
 457         /* now map from address 0 */
 458         addr = wine_anon_mmap( NULL, 0x110000, PROT_READ | PROT_WRITE | PROT_EXEC, MAP_FIXED );
 459         if (addr)
 460         {
 461             ERR("MAP_FIXED failed at address 0 for DOS address space\n" );
 462             ExitProcess(1);
 463         }
 464
 465         /* inform the memory manager that there is a mapping here */
 466         VirtualAlloc( addr, 0x110000, MEM_RESERVE | MEM_SYSTEM, PAGE_EXECUTE_READWRITE );
 467
 468         /* protect the first 64K to catch NULL pointers */
 469         if (!dos_init)
 470         {
 471             VirtualProtect( addr, 0x10000, PAGE_NOACCESS, NULL );
 472             /* move the BIOS and ISR area from 0x00000 to 0xf0000 */
 473             sys_offset += 0xf0000;
 474         }
 475     }
 476     else
 477     {
 478         ERR("Cannot use first megabyte for DOS address space, please report\n" );
 479         if (dos_init) ExitProcess(1);
 480         /* allocate the DOS area somewhere else */
 481         addr = VirtualAlloc( NULL, 0x110000, MEM_COMMIT, PAGE_EXECUTE_READWRITE );
 482         if (!addr)
 483         {
 484             ERR( "Cannot allocate DOS memory\n" );
 485             ExitProcess(1);
 486         }
 487     }
 488     DOSMEM_dosmem = addr;
 489     DOSMEM_sysmem = (char*)addr + sys_offset;
 490 }
 491
 492
 493 /***********************************************************************
 494  *           DOSMEM_Init
 495  *
 496  * Create the dos memory segments, and store them into the KERNEL
 497  * exported values.
 498  */
 499 BOOL DOSMEM_Init(BOOL dos_init)
 500 {
 501     static int already_done, already_mapped;
 502
 503     if (!already_done)
 504     {
 505         setup_dos_mem( dos_init );
 506
 507         DOSMEM_0000H = GLOBAL_CreateBlock( GMEM_FIXED, DOSMEM_sysmem,
 508                                            0x10000, 0, WINE_LDT_FLAGS_DATA );
 509         DOSMEM_BiosDataSeg = GLOBAL_CreateBlock(GMEM_FIXED,DOSMEM_sysmem + 0x400,
 510                                                 0x100, 0, WINE_LDT_FLAGS_DATA );
 511         DOSMEM_BiosSysSeg = GLOBAL_CreateBlock(GMEM_FIXED,DOSMEM_dosmem+0xf0000,
 512                                                0x10000, 0, WINE_LDT_FLAGS_DATA );
 513         DOSMEM_FillBiosSegments();
 514         DOSMEM_FillIsrTable();
 515         DOSMEM_InitMemory();
 516         DOSMEM_InitCollateTable();
 517         DOSMEM_InitErrorTable();
 518         DOSMEM_InitDPMI();
 519         DOSDEV_InstallDOSDevices();
 520         already_done = 1;
 521     }
 522     else if (dos_init && !already_mapped)
 523     {
 524         if (DOSMEM_dosmem)
 525         {
 526             ERR( "Needs access to the first megabyte for DOS mode\n" );
 527             ExitProcess(1);
 528         }
 529         MESSAGE( "Warning: unprotecting the first 64KB of memory to allow real-mode calls.\n"
 530                  "         NULL pointer accesses will no longer be caught.\n" );
 531         VirtualProtect( NULL, 0x10000, PAGE_EXECUTE_READWRITE, NULL );
 532         /* copy the BIOS and ISR area down */
 533         memcpy( DOSMEM_dosmem, DOSMEM_sysmem, 0x400 + 0x100 );
 534         DOSMEM_sysmem = DOSMEM_dosmem;
 535         SetSelectorBase( DOSMEM_0000H, 0 );
 536         SetSelectorBase( DOSMEM_BiosDataSeg, 0x400 );
 537         /* we may now need the actual interrupt stubs, and since we've just moved the
 538          * interrupt vector table away, we can fill the area with stubs instead... */
 539         DOSMEM_MakeIsrStubs();
 540         already_mapped = 1;
 541     }
 542     return TRUE;
 543 }
 544
 545
 546 /***********************************************************************
 547  *           DOSMEM_Tick
 548  *
 549  * Increment the BIOS tick counter. Called by timer signal handler.
 550  */
 551 void DOSMEM_Tick( WORD timer )
 552 {
 553     BIOSDATA *pBiosData = DOSMEM_BiosData();
 554     if (pBiosData) pBiosData->Ticks++;
 555 }
 556
 557 /***********************************************************************
 558  *           DOSMEM_GetBlock
 559  *
 560  * Carve a chunk of the DOS memory block (without selector).
 561  */
 562 LPVOID DOSMEM_GetBlock(UINT size, UINT16* pseg)
 563 {
 564    UINT          blocksize;
 565    char         *block = NULL;
 566    dosmem_info  *info_block = DOSMEM_InfoBlock();
 567    dosmem_entry *dm;
 568 #ifdef __DOSMEM_DEBUG_
 569    dosmem_entry *prev = NULL;
 570 #endif
 571
 572    if( size > info_block->free ) return NULL;
 573    dm = DOSMEM_RootBlock();
 574
 575    while (dm && dm->size != DM_BLOCK_TERMINAL)
 576    {
 577 #ifdef __DOSMEM_DEBUG__
 578        if( (dm->size & DM_BLOCK_DEBUG) != DM_BLOCK_DEBUG )
 579        {
 580             WARN("MCB overrun! [prev = 0x%08x]\n", 4 + (UINT)prev);
 581             return NULL;
 582        }
 583        prev = dm;
 584 #endif
 585        if( dm->size & DM_BLOCK_FREE )
 586        {
 587            dosmem_entry  *next = NEXT_BLOCK(dm);
 588
 589            while( next->size & DM_BLOCK_FREE ) /* collapse free blocks */
 590            {
 591                dm->size += sizeof(dosmem_entry) + (next->size & DM_BLOCK_MASK);
 592                next->size = (DM_BLOCK_FREE | DM_BLOCK_TERMINAL);
 593                next = NEXT_BLOCK(dm);
 594            }
 595
 596            blocksize = dm->size & DM_BLOCK_MASK;
 597            if( blocksize >= size )
 598            {
 599                block = ((char*)dm) + sizeof(dosmem_entry);
 600                if( blocksize - size > 0x20 )
 601                {
 602                    /* split dm so that the next one stays
 603                     * paragraph-aligned (and dm loses free bit) */
 604
 605                    dm->size = (((size + 0xf + sizeof(dosmem_entry)) & ~0xf) -
 606                                               sizeof(dosmem_entry));
 607                    next = (dosmem_entry*)(((char*)dm) +
 608                            sizeof(dosmem_entry) + dm->size);
 609                    next->size = (blocksize - (dm->size +
 610                            sizeof(dosmem_entry))) | DM_BLOCK_FREE
 611 #ifdef __DOSMEM_DEBUG__
 612                                                   | DM_BLOCK_DEBUG
 613 #endif
 614                                                   ;
 615                } else dm->size &= DM_BLOCK_MASK;
 616
 617                info_block->blocks++;
 618                info_block->free -= dm->size;
 619                if( pseg ) *pseg = (block - DOSMEM_dosmem) >> 4;
 620 #ifdef __DOSMEM_DEBUG__
 621                dm->size |= DM_BLOCK_DEBUG;
 622 #endif
 623                break;
 624            }
 625            dm = next;
 626        }
 627        else dm = NEXT_BLOCK(dm);
 628    }
 629    return (LPVOID)block;
 630 }
 631
 632 /***********************************************************************
 633  *           DOSMEM_FreeBlock
 634  */
 635 BOOL DOSMEM_FreeBlock(void* ptr)
 636 {
 637    dosmem_info  *info_block = DOSMEM_InfoBlock();
 638
 639    if( ptr >= (void*)(((char*)DOSMEM_RootBlock()) + sizeof(dosmem_entry)) &&
 640        ptr < (void*)DOSMEM_MemoryTop() && !((((char*)ptr)
 641                   - DOSMEM_dosmem) & 0xf) )
 642    {
 643        dosmem_entry  *dm = (dosmem_entry*)(((char*)ptr) - sizeof(dosmem_entry));
 644
 645        if( !(dm->size & (DM_BLOCK_FREE | DM_BLOCK_TERMINAL))
 646 #ifdef __DOSMEM_DEBUG__
 647          && ((dm->size & DM_BLOCK_DEBUG) == DM_BLOCK_DEBUG )
 648 #endif
 649          )
 650        {
 651              info_block->blocks--;
 652              info_block->free += dm->size;
 653
 654              dm->size |= DM_BLOCK_FREE;
 655              return TRUE;
 656        }
 657    }
 658    return FALSE;
 659 }
 660
 661 /***********************************************************************
 662  *           DOSMEM_ResizeBlock
 663  */
 664 LPVOID DOSMEM_ResizeBlock(void* ptr, UINT size, UINT16* pseg)
 665 {
 666    char         *block = NULL;
 667    dosmem_info  *info_block = DOSMEM_InfoBlock();
 668
 669    if( ptr >= (void*)(((char*)DOSMEM_RootBlock()) + sizeof(dosmem_entry)) &&
 670        ptr < (void*)DOSMEM_MemoryTop() && !((((char*)ptr)
 671                   - DOSMEM_dosmem) & 0xf) )
 672    {
 673        dosmem_entry  *dm = (dosmem_entry*)(((char*)ptr) - sizeof(dosmem_entry));
 674
 675        if( pseg ) *pseg = ((char*)ptr - DOSMEM_dosmem) >> 4;
 676
 677        if( !(dm->size & (DM_BLOCK_FREE | DM_BLOCK_TERMINAL))
 678          )
 679        {
 680              dosmem_entry  *next = NEXT_BLOCK(dm);
 681              UINT blocksize, orgsize = dm->size & DM_BLOCK_MASK;
 682
 683              while( next->size & DM_BLOCK_FREE ) /* collapse free blocks */
 684              {
 685                  dm->size += sizeof(dosmem_entry) + (next->size & DM_BLOCK_MASK);
 686                  next->size = (DM_BLOCK_FREE | DM_BLOCK_TERMINAL);
 687                  next = NEXT_BLOCK(dm);
 688              }
 689
 690              blocksize = dm->size & DM_BLOCK_MASK;
 691              if (blocksize >= size)
 692              {
 693                  block = ((char*)dm) + sizeof(dosmem_entry);
 694                  if( blocksize - size > 0x20 )
 695                  {
 696                      /* split dm so that the next one stays
 697                       * paragraph-aligned (and next gains free bit) */
 698
 699                      dm->size = (((size + 0xf + sizeof(dosmem_entry)) & ~0xf) -
 700                                                 sizeof(dosmem_entry));
 701                      next = (dosmem_entry*)(((char*)dm) +
 702                              sizeof(dosmem_entry) + dm->size);
 703                      next->size = (blocksize - (dm->size +
 704                              sizeof(dosmem_entry))) | DM_BLOCK_FREE
 705                                                     ;
 706                  } else dm->size &= DM_BLOCK_MASK;
 707
 708                  info_block->free += orgsize - dm->size;
 709              } else {
 710                  /* the collapse didn't help, try getting a new block */
 711                  block = DOSMEM_GetBlock(size, pseg);
 712                  if (block) {
 713                      /* we got one, copy the old data there (we do need to, right?) */
 714                      memcpy(block, ((char*)dm) + sizeof(dosmem_entry),
 715                                    (size<orgsize) ? size : orgsize);
 716                      /* free old block */
 717                      info_block->blocks--;
 718                      info_block->free += dm->size;
 719
 720                      dm->size |= DM_BLOCK_FREE;
 721                  } else {
 722                      /* and Bill Gates said 640K should be enough for everyone... */
 723
 724                      /* need to split original and collapsed blocks apart again,
 725                       * and free the collapsed blocks again, before exiting */
 726                      if( blocksize - orgsize > 0x20 )
 727                      {
 728                          /* split dm so that the next one stays
 729                           * paragraph-aligned (and next gains free bit) */
 730
 731                          dm->size = (((orgsize + 0xf + sizeof(dosmem_entry)) & ~0xf) -
 732                                                        sizeof(dosmem_entry));
 733                          next = (dosmem_entry*)(((char*)dm) +
 734                                  sizeof(dosmem_entry) + dm->size);
 735                          next->size = (blocksize - (dm->size +
 736                                  sizeof(dosmem_entry))) | DM_BLOCK_FREE
 737                                                         ;
 738                      } else dm->size &= DM_BLOCK_MASK;
 739                  }
 740              }
 741        }
 742    }
 743    return (LPVOID)block;
 744 }
 745
 746
 747 /***********************************************************************
 748  *           DOSMEM_Available
 749  */
 750 UINT DOSMEM_Available(void)
 751 {
 752    UINT          blocksize, available = 0;
 753    dosmem_entry *dm;
 754
 755    dm = DOSMEM_RootBlock();
 756
 757    while (dm && dm->size != DM_BLOCK_TERMINAL)
 758    {
 759 #ifdef __DOSMEM_DEBUG__
 760        if( (dm->size & DM_BLOCK_DEBUG) != DM_BLOCK_DEBUG )
 761        {
 762             WARN("MCB overrun! [prev = 0x%08x]\n", 4 + (UINT)prev);
 763             return NULL;
 764        }
 765        prev = dm;
 766 #endif
 767        if( dm->size & DM_BLOCK_FREE )
 768        {
 769            dosmem_entry  *next = NEXT_BLOCK(dm);
 770
 771            while( next->size & DM_BLOCK_FREE ) /* collapse free blocks */
 772            {
 773                dm->size += sizeof(dosmem_entry) + (next->size & DM_BLOCK_MASK);
 774                next->size = (DM_BLOCK_FREE | DM_BLOCK_TERMINAL);
 775                next = NEXT_BLOCK(dm);
 776            }
 777
 778            blocksize = dm->size & DM_BLOCK_MASK;
 779            if ( blocksize > available ) available = blocksize;
 780            dm = next;
 781        }
 782        else dm = NEXT_BLOCK(dm);
 783    }
 784    return available;
 785 }
 786
 787
 788 /***********************************************************************
 789  *           DOSMEM_MapLinearToDos
 790  *
 791  * Linear address to the DOS address space.
 792  */
 793 UINT DOSMEM_MapLinearToDos(LPVOID ptr)
 794 {
 795     if (((char*)ptr >= DOSMEM_dosmem) &&
 796         ((char*)ptr < DOSMEM_dosmem + 0x100000))
 797           return (UINT)ptr - (UINT)DOSMEM_dosmem;
 798     return (UINT)ptr;
 799 }
 800
 801
 802 /***********************************************************************
 803  *           DOSMEM_MapDosToLinear
 804  *
 805  * DOS linear address to the linear address space.
 806  */
 807 LPVOID DOSMEM_MapDosToLinear(UINT ptr)
 808 {
 809     if (ptr < 0x100000) return (LPVOID)(ptr + (UINT)DOSMEM_dosmem);
 810     return (LPVOID)ptr;
 811 }
 812
 813
 814 /***********************************************************************
 815  *           DOSMEM_MapRealToLinear
 816  *
 817  * Real mode DOS address into a linear pointer
 818  */
 819 LPVOID DOSMEM_MapRealToLinear(DWORD x)
 820 {
 821    LPVOID       lin;
 822
 823    lin=DOSMEM_dosmem+(x&0xffff)+(((x&0xffff0000)>>16)*16);
 824    TRACE_(selector)("(0x%08lx) returns 0x%p.\n", x, lin );
 825    return lin;
 826 }
 827
 828 /***********************************************************************
 829  *           DOSMEM_AllocSelector
 830  *
 831  * Allocates a protected mode selector for a realmode segment.
 832  */
 833 WORD DOSMEM_AllocSelector(WORD realsel)
 834 {
 835         HMODULE16 hModule = GetModuleHandle16("KERNEL");
 836         WORD    sel;
 837
 838         sel=GLOBAL_CreateBlock( GMEM_FIXED, DOSMEM_dosmem+realsel*16, 0x10000,
 839                                 hModule, WINE_LDT_FLAGS_DATA );
 840         TRACE_(selector)("(0x%04x) returns 0x%04x.\n", realsel,sel);
 841         return sel;
 842 }
 843