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