msdos/dosmem.c

   1 /*
   2  * DOS memory emulation
   3  *
   4  * Copyright 1995 Alexandre Julliard
   5  * Copyright 1996 Marcus Meissner
   6  */
   7
   8 #include <signal.h>
   9 #include <stdlib.h>
  10 #include <string.h>
  11 #include "winbase.h"
  12 #include "wine/winbase16.h"
  13 #include "global.h"
  14 #include "ldt.h"
  15 #include "miscemu.h"
  16 #include "vga.h"
  17 #include "module.h"
  18 #include "task.h"
  19 #include "debugtools.h"
  20
  21 DECLARE_DEBUG_CHANNEL(dosmem)
  22 DECLARE_DEBUG_CHANNEL(selector)
  23
  24 HANDLE16 DOSMEM_BiosDataSeg;  /* BIOS data segment at 0x40:0 */
  25 HANDLE16 DOSMEM_BiosSysSeg;   /* BIOS ROM segment at 0xf000:0 */
  26
  27 static char     *DOSMEM_dosmem;
  28
  29        DWORD     DOSMEM_CollateTable;
  30
  31        DWORD     DOSMEM_ErrorCall;
  32        DWORD     DOSMEM_ErrorBuffer;
  33
  34 /* use 2 low bits of 'size' for the housekeeping */
  35
  36 #define DM_BLOCK_DEBUG          0xABE00000
  37 #define DM_BLOCK_TERMINAL       0x00000001
  38 #define DM_BLOCK_FREE           0x00000002
  39 #define DM_BLOCK_MASK           0x001FFFFC
  40
  41 /*
  42 #define __DOSMEM_DEBUG__
  43  */
  44
  45 typedef struct {
  46    unsigned     size;
  47 } dosmem_entry;
  48
  49 typedef struct {
  50   unsigned      blocks;
  51   unsigned      free;
  52 } dosmem_info;
  53
  54 #define NEXT_BLOCK(block) \
  55         (dosmem_entry*)(((char*)(block)) + \
  56          sizeof(dosmem_entry) + ((block)->size & DM_BLOCK_MASK))
  57
  58 #define VM_STUB(x) (0x90CF00CD|(x<<8)) /* INT x; IRET; NOP */
  59 #define VM_STUB_SEGMENT 0xf000         /* BIOS segment */
  60
  61 /***********************************************************************
  62  *           DOSMEM_MemoryBase
  63  *
  64  * Gets the DOS memory base.
  65  */
  66 char *DOSMEM_MemoryBase(HMODULE16 hModule)
  67 {
  68     TDB *pTask = hModule ? NULL : (TDB *)GlobalLock16( GetCurrentTask() );
  69     NE_MODULE *pModule = (hModule || pTask) ? NE_GetPtr( hModule ? hModule : pTask->hModule ) : NULL;
  70
  71     GlobalUnlock16( GetCurrentTask() );
  72     if (pModule && pModule->dos_image)
  73         return pModule->dos_image;
  74     else
  75         return DOSMEM_dosmem;
  76 }
  77
  78 /***********************************************************************
  79  *           DOSMEM_MemoryTop
  80  *
  81  * Gets the DOS memory top.
  82  */
  83 static char *DOSMEM_MemoryTop(HMODULE16 hModule)
  84 {
  85     return DOSMEM_MemoryBase(hModule)+0x9FFFC; /* 640K */
  86 }
  87
  88 /***********************************************************************
  89  *           DOSMEM_InfoBlock
  90  *
  91  * Gets the DOS memory info block.
  92  */
  93 static dosmem_info *DOSMEM_InfoBlock(HMODULE16 hModule)
  94 {
  95     return (dosmem_info*)(DOSMEM_MemoryBase(hModule)+0x10000); /* 64K */
  96 }
  97
  98 /***********************************************************************
  99  *           DOSMEM_RootBlock
 100  *
 101  * Gets the DOS memory root block.
 102  */
 103 static dosmem_entry *DOSMEM_RootBlock(HMODULE16 hModule)
 104 {
 105     /* first block has to be paragraph-aligned */
 106     return (dosmem_entry*)(((char*)DOSMEM_InfoBlock(hModule)) +
 107                            ((((sizeof(dosmem_info) + 0xf) & ~0xf) - sizeof(dosmem_entry))));
 108 }
 109
 110 /***********************************************************************
 111  *           DOSMEM_FillIsrTable
 112  *
 113  * Fill the interrupt table with fake BIOS calls to BIOSSEG (0xf000).
 114  *
 115  * NOTES:
 116  * Linux normally only traps INTs performed from or destined to BIOSSEG
 117  * for us to handle, if the int_revectored table is empty. Filling the
 118  * interrupt table with calls to INT stubs in BIOSSEG allows DOS programs
 119  * to hook interrupts, as well as use their familiar retf tricks to call
 120  * them, AND let Wine handle any unhooked interrupts transparently.
 121  */
 122 static void DOSMEM_FillIsrTable(HMODULE16 hModule)
 123 {
 124     SEGPTR *isr = (SEGPTR*)DOSMEM_MemoryBase(hModule);
 125     DWORD *stub = (DWORD*)((char*)isr + (VM_STUB_SEGMENT << 4));
 126     int x;
 127
 128     for (x=0; x<256; x++) isr[x]=PTR_SEG_OFF_TO_SEGPTR(VM_STUB_SEGMENT,x*4);
 129     for (x=0; x<256; x++) stub[x]=VM_STUB(x);
 130 }
 131
 132 /***********************************************************************
 133  *           DOSMEM_InitDPMI
 134  *
 135  * Allocate the global DPMI RMCB wrapper.
 136  */
 137 static void DOSMEM_InitDPMI(void)
 138 {
 139     extern UINT16 DPMI_wrap_seg;
 140     static char wrap_code[]={
 141      0xCD,0x31, /* int $0x31 */
 142      0xCB       /* lret */
 143     };
 144     LPSTR wrapper = (LPSTR)DOSMEM_GetBlock(0, sizeof(wrap_code), &DPMI_wrap_seg);
 145
 146     memcpy(wrapper, wrap_code, sizeof(wrap_code));
 147 }
 148
 149 BIOSDATA * DOSMEM_BiosData()
 150 {
 151     return (BIOSDATA *)(DOSMEM_MemoryBase(0)+0x400);
 152 }
 153
 154 BYTE * DOSMEM_BiosSys()
 155 {
 156     return DOSMEM_MemoryBase(0)+0xf0000;
 157 }
 158
 159 struct _DOS_LISTOFLISTS * DOSMEM_LOL()
 160 {
 161     return (struct _DOS_LISTOFLISTS *)DOSMEM_MapRealToLinear
 162       (PTR_SEG_OFF_TO_SEGPTR(HIWORD(DOS_LOLSeg),0));
 163 }
 164
 165 /***********************************************************************
 166  *           DOSMEM_FillBiosSegments
 167  *
 168  * Fill the BIOS data segment with dummy values.
 169  */
 170 static void DOSMEM_FillBiosSegments(void)
 171 {
 172     BYTE *pBiosSys = (BYTE *)GlobalLock16( DOSMEM_BiosSysSeg );
 173     BYTE *pBiosROMTable = pBiosSys+0xe6f5;
 174     BIOSDATA *pBiosData = (BIOSDATA *)GlobalLock16( DOSMEM_BiosDataSeg );
 175
 176     /* bogus 0xe0xx addresses !! Adapt int 0x10/0x1b if change needed */
 177     BYTE *pVideoStaticFuncTable = pBiosSys+0xe000;
 178     BYTE *pVideoStateInfo = pBiosSys+0xe010;
 179     BYTE *p;
 180     int i;
 181
 182       /* Clear all unused values */
 183     memset( pBiosData, 0, sizeof(*pBiosData) );
 184
 185     /* FIXME: should check the number of configured drives and ports */
 186
 187     pBiosData->Com1Addr             = 0x3f8;
 188     pBiosData->Com2Addr             = 0x2f8;
 189     pBiosData->Lpt1Addr             = 0x378;
 190     pBiosData->Lpt2Addr             = 0x278;
 191     pBiosData->InstalledHardware    = 0x5463;
 192     pBiosData->MemSize              = 640;
 193     pBiosData->NextKbdCharPtr       = 0x1e;
 194     pBiosData->FirstKbdCharPtr      = 0x1e;
 195     pBiosData->VideoMode            = 3;
 196     pBiosData->VideoColumns         = 80;
 197     pBiosData->VideoPageSize        = 80 * 25 * 2;
 198     pBiosData->VideoPageStartAddr   = 0xb800;
 199     pBiosData->VideoCtrlAddr        = 0x3d4;
 200     pBiosData->Ticks                = INT1A_GetTicksSinceMidnight();
 201     pBiosData->NbHardDisks          = 2;
 202     pBiosData->KbdBufferStart       = 0x1e;
 203     pBiosData->KbdBufferEnd         = 0x3e;
 204     pBiosData->RowsOnScreenMinus1   = 23;
 205     pBiosData->BytesPerChar         = 0x10;
 206     pBiosData->ModeOptions          = 0x64;
 207     pBiosData->FeatureBitsSwitches  = 0xf9;
 208     pBiosData->VGASettings          = 0x51;
 209     pBiosData->DisplayCombination   = 0x08;
 210     pBiosData->DiskDataRate         = 0;
 211
 212     /* fill ROM configuration table (values from Award) */
 213     *(WORD *)(pBiosROMTable)= 0x08; /* number of bytes following */
 214     *(pBiosROMTable+0x2)        = 0xfc; /* model */
 215     *(pBiosROMTable+0x3)        = 0x01; /* submodel */
 216     *(pBiosROMTable+0x4)        = 0x00; /* BIOS revision */
 217     *(pBiosROMTable+0x5)        = 0x74; /* feature byte 1 */
 218     *(pBiosROMTable+0x6)        = 0x00; /* feature byte 2 */
 219     *(pBiosROMTable+0x7)        = 0x00; /* feature byte 3 */
 220     *(pBiosROMTable+0x8)        = 0x00; /* feature byte 4 */
 221     *(pBiosROMTable+0x9)        = 0x00; /* feature byte 5 */
 222
 223     p = pVideoStaticFuncTable;
 224     for (i=0; i < 7; i++)
 225       *(p+i)  = 0xff; /* modes supported 1 to 7 */
 226
 227     *(p+0x7)  = 7;                  /* scan lines supported */
 228     *(p+0x8)  = 0;                  /* tot nr of char blocks in text mode */
 229     *(p+0x9)  = 0;                  /* max nr of active char blocks in text */
 230     *(WORD *)(p+0xa) = 0x8ff;       /* misc support flags */
 231     *(WORD *)(p+0xc) = 0;           /* reserved */
 232     *(p+0xe)  = 0x3f;               /* save pointer function flags */
 233     *(p+0xf)  = 0;                  /* reserved */
 234
 235     p = pVideoStateInfo;
 236     *(DWORD *)p = 0xf000e000;       /* address of pVideoStaticFuncTable, FIXME: always real mode ? */
 237     *(p+0x04) =                     /* current video mode, needs updates ! */
 238       pBiosData->VideoMode;
 239     *(WORD *)(p+0x05) =             /* number of columns, needs updates ! */
 240       pBiosData->VideoColumns;
 241     *(WORD *)(p+0x07) = 0;          /* length of regen (???) buffer in bytes */
 242     *(WORD *)(p+0x09) = 0;          /* starting address of regen (?) buffer */
 243     *(WORD *)(p+0x0b) = 0;          /* cursorpos page 0 */
 244     *(WORD *)(p+0x0d) = 0;          /* cursorpos page 1 */
 245     *(WORD *)(p+0x0f) = 0;          /* page 2 */
 246     *(WORD *)(p+0x11) = 0;          /* page 3 */
 247     *(WORD *)(p+0x13) = 0;          /* page 4 */
 248     *(WORD *)(p+0x15) = 0;          /* page 5 */
 249     *(WORD *)(p+0x17) = 0;          /* page 6 */
 250     *(WORD *)(p+0x19) = 0;          /* page 7 */
 251     *(WORD *)(p+0x1b) = 0x0a0b;     /* cursor size (start/end line) */
 252     *(p+0x1d) = 0;                  /* active display page */
 253     *(WORD *)(p+0x1e) = 0x3da;      /* CRTC port address */
 254     *(p+0x20) = 0x0;                /* current setting of port 0x3x8 */
 255     *(p+0x21) = 0x0;                /* current setting of port 0x3x9 */
 256     *(p+0x22) = 23;                 /* number of rows - 1 */
 257     *(WORD *)(p+0x23) = 0x10;       /* bytes/character */
 258     *(p+0x25) =                     /* comb. of active display */
 259       pBiosData->DisplayCombination;
 260     *(p+0x26) = 0;                  /* DCC (???) of alternate display */
 261     *(WORD *)(p+0x27) = 16;         /* number of colors in current mode */
 262     *(p+0x29) = 1;                  /* number of pages in current mode */
 263     *(p+0x2a) = 3;                  /* number of scan lines active */
 264                                     /* (0,1,2,3) =  (200,350,400,480) */
 265     *(p+0x2b) = 0;                  /* primary character block (?) */
 266     *(p+0x2c) = 0;                  /* secondary character block (?) */
 267     *(p+0x2d) =                     /* miscellaneous flags */
 268         (pBiosData->VGASettings & 0x0f)
 269       | ((pBiosData->ModeOptions & 1) << 4); /* cursor emulation */
 270     *(p+0x2e) = 0;                  /* non-VGA mode support */
 271     *(WORD *)(p+0x2f) = 0;          /* reserved */
 272     *(p+0x31) =                     /* video memory available */
 273       (pBiosData->ModeOptions & 0x60 >> 5);
 274     *(p+0x32) = 0;                  /* save pointer state flags */
 275     *(p+0x33) = 4;                  /* display info and status */
 276
 277     /* BIOS date string */
 278     strcpy((char *)pBiosSys+0xfff5, "13/01/99");
 279
 280     /* BIOS ID */
 281     *(pBiosSys+0xfffe) = 0xfc;
 282 }
 283
 284 /***********************************************************************
 285  *           DOSMEM_InitCollateTable
 286  *
 287  * Initialises the collate table (character sorting, language dependent)
 288  */
 289 static void DOSMEM_InitCollateTable()
 290 {
 291         DWORD           x;
 292         unsigned char   *tbl;
 293         int             i;
 294
 295         x = GlobalDOSAlloc16(258);
 296         DOSMEM_CollateTable = MAKELONG(0,(x>>16));
 297         tbl = DOSMEM_MapRealToLinear(DOSMEM_CollateTable);
 298         *(WORD*)tbl     = 0x100;
 299         tbl += 2;
 300         for ( i = 0; i < 0x100; i++) *tbl++ = i;
 301 }
 302
 303 /***********************************************************************
 304  *           DOSMEM_InitErrorTable
 305  *
 306  * Initialises the error tables (DOS 5+)
 307  */
 308 static void DOSMEM_InitErrorTable()
 309 {
 310         DWORD           x;
 311         char            *call;
 312
 313         /* We will use a snippet of real mode code that calls */
 314         /* a WINE-only interrupt to handle moving the requested */
 315         /* message into the buffer... */
 316
 317         /* FIXME - There is still something wrong... */
 318
 319         /* FIXME - Find hex values for opcodes...
 320
 321            (On call, AX contains message number
 322                      DI contains 'offset' (??)
 323             Resturn, ES:DI points to counted string )
 324
 325            PUSH BX
 326            MOV BX, AX
 327            MOV AX, (arbitrary subfunction number)
 328            INT (WINE-only interrupt)
 329            POP BX
 330            RET
 331
 332         */
 333
 334         const int       code = 4;
 335         const int       buffer = 80;
 336         const int       SIZE_TO_ALLOCATE = code + buffer;
 337
 338         /* FIXME - Complete rewrite of the table system to save */
 339         /* precious DOS space. Now, we return the 0001:???? as */
 340         /* DOS 4+ (??, it seems to be the case in MS 7.10) treats that */
 341         /* as a special case and programs will use the alternate */
 342         /* interface (a farcall returned with INT 24 (AX = 0x122e, DL = */
 343         /* 0x08) which lets us have a smaller memory footprint anyway. */
 344
 345         x = GlobalDOSAlloc16(SIZE_TO_ALLOCATE);
 346
 347         DOSMEM_ErrorCall = MAKELONG(0,(x>>16));
 348         DOSMEM_ErrorBuffer = DOSMEM_ErrorCall + code;
 349
 350         call = DOSMEM_MapRealToLinear(DOSMEM_ErrorCall);
 351
 352         memset(call, 0, SIZE_TO_ALLOCATE);
 353
 354         /* Fixme - Copy assembly into buffer here */
 355 }
 356
 357 /***********************************************************************
 358  *           DOSMEM_InitMemory
 359  *
 360  * Initialises the DOS memory structures.
 361  */
 362 static void DOSMEM_InitMemory(HMODULE16 hModule)
 363 {
 364    /* Low 64Kb are reserved for DOS/BIOS so the useable area starts at
 365     * 1000:0000 and ends at 9FFF:FFEF. */
 366
 367     dosmem_info*        info_block = DOSMEM_InfoBlock(hModule);
 368     dosmem_entry*       root_block = DOSMEM_RootBlock(hModule);
 369     dosmem_entry*       dm;
 370
 371     root_block->size = DOSMEM_MemoryTop(hModule) - (((char*)root_block) + sizeof(dosmem_entry));
 372
 373     info_block->blocks = 0;
 374     info_block->free = root_block->size;
 375
 376     dm = NEXT_BLOCK(root_block);
 377     dm->size = DM_BLOCK_TERMINAL;
 378     root_block->size |= DM_BLOCK_FREE
 379 #ifdef __DOSMEM_DEBUG__
 380                      | DM_BLOCK_DEBUG;
 381 #endif
 382                      ;
 383 }
 384
 385 /***********************************************************************
 386  *           DOSMEM_MovePointers
 387  *
 388  * Relocates any pointers into DOS memory to a new address space.
 389  */
 390 static void DOSMEM_MovePointers(LPVOID dest, LPVOID src, DWORD size)
 391 {
 392   unsigned long delta = dest-src;
 393   unsigned cnt;
 394   ldt_entry ent;
 395
 396   /* relocate base addresses of any selectors pointing into memory */
 397   for (cnt=FIRST_LDT_ENTRY_TO_ALLOC; cnt<LDT_SIZE; cnt++) {
 398     LDT_GetEntry(cnt, &ent);
 399     if ((ent.base >= (unsigned long)src) && \
 400         (ent.base < ((unsigned long)src + size))) {
 401       ent.base += delta;
 402       LDT_SetEntry(cnt, &ent);
 403     }
 404   }
 405 }
 406
 407 /***********************************************************************
 408  *           DOSMEM_Init
 409  *
 410  * Create the dos memory segments, and store them into the KERNEL
 411  * exported values.
 412  */
 413 BOOL DOSMEM_Init(HMODULE16 hModule)
 414 {
 415     if (!hModule)
 416     {
 417         /* Allocate 1 MB dosmemory
 418          * - it is mostly wasted but we can use some of it to
 419          *   store internal translation tables, etc...
 420          */
 421         DOSMEM_dosmem = VirtualAlloc( NULL, 0x100000, MEM_COMMIT,
 422                                       PAGE_EXECUTE_READWRITE );
 423         if (!DOSMEM_dosmem)
 424         {
 425             WARN_(dosmem)("Could not allocate DOS memory.\n" );
 426             return FALSE;
 427         }
 428         DOSMEM_BiosDataSeg = GLOBAL_CreateBlock(GMEM_FIXED,DOSMEM_dosmem+0x400,
 429                                      0x100, 0, FALSE, FALSE, FALSE, NULL );
 430         DOSMEM_BiosSysSeg = GLOBAL_CreateBlock(GMEM_FIXED,DOSMEM_dosmem+0xf0000,
 431                                      0x10000, 0, FALSE, FALSE, FALSE, NULL );
 432         DOSMEM_FillIsrTable(0);
 433         DOSMEM_FillBiosSegments();
 434         DOSMEM_InitMemory(0);
 435         DOSMEM_InitCollateTable();
 436         DOSMEM_InitErrorTable();
 437         DOSMEM_InitDPMI();
 438         DOSDEV_InstallDOSDevices();
 439     }
 440     else
 441     {
 442 #if 0
 443         DOSMEM_FillIsrTable(hModule);
 444         DOSMEM_InitMemory(hModule);
 445 #else
 446         LPVOID base = DOSMEM_MemoryBase(hModule);
 447
 448         /* bootstrap the new V86 task with a copy of the "system" memory */
 449         memcpy(base, DOSMEM_dosmem, 0x100000);
 450         /* then move existing selectors to it */
 451         DOSMEM_MovePointers(base, DOSMEM_dosmem, 0x100000);
 452 #endif
 453     }
 454     return TRUE;
 455 }
 456
 457
 458 /***********************************************************************
 459  *           DOSMEM_Tick
 460  *
 461  * Increment the BIOS tick counter. Called by timer signal handler.
 462  */
 463 void DOSMEM_Tick( WORD timer )
 464 {
 465     BIOSDATA *pBiosData = DOSMEM_BiosData();
 466     if (pBiosData) pBiosData->Ticks++;
 467 }
 468
 469 /***********************************************************************
 470  *           DOSMEM_GetBlock
 471  *
 472  * Carve a chunk of the DOS memory block (without selector).
 473  */
 474 LPVOID DOSMEM_GetBlock(HMODULE16 hModule, UINT size, UINT16* pseg)
 475 {
 476    UINT          blocksize;
 477    char         *block = NULL;
 478    dosmem_info  *info_block = DOSMEM_InfoBlock(hModule);
 479    dosmem_entry *dm;
 480 #ifdef __DOSMEM_DEBUG_
 481    dosmem_entry *prev = NULL;
 482 #endif
 483
 484    if( size > info_block->free ) return NULL;
 485    dm = DOSMEM_RootBlock(hModule);
 486
 487    while (dm && dm->size != DM_BLOCK_TERMINAL)
 488    {
 489 #ifdef __DOSMEM_DEBUG__
 490        if( (dm->size & DM_BLOCK_DEBUG) != DM_BLOCK_DEBUG )
 491        {
 492             WARN_(dosmem)("MCB overrun! [prev = 0x%08x]\n", 4 + (UINT)prev);
 493             return NULL;
 494        }
 495        prev = dm;
 496 #endif
 497        if( dm->size & DM_BLOCK_FREE )
 498        {
 499            dosmem_entry  *next = NEXT_BLOCK(dm);
 500
 501            while( next->size & DM_BLOCK_FREE ) /* collapse free blocks */
 502            {
 503                dm->size += sizeof(dosmem_entry) + (next->size & DM_BLOCK_MASK);
 504                next->size = (DM_BLOCK_FREE | DM_BLOCK_TERMINAL);
 505                next = NEXT_BLOCK(dm);
 506            }
 507
 508            blocksize = dm->size & DM_BLOCK_MASK;
 509            if( blocksize >= size )
 510            {
 511                block = ((char*)dm) + sizeof(dosmem_entry);
 512                if( blocksize - size > 0x20 )
 513                {
 514                    /* split dm so that the next one stays
 515                     * paragraph-aligned (and dm loses free bit) */
 516
 517                    dm->size = (((size + 0xf + sizeof(dosmem_entry)) & ~0xf) -
 518                                               sizeof(dosmem_entry));
 519                    next = (dosmem_entry*)(((char*)dm) +
 520                            sizeof(dosmem_entry) + dm->size);
 521                    next->size = (blocksize - (dm->size +
 522                            sizeof(dosmem_entry))) | DM_BLOCK_FREE
 523 #ifdef __DOSMEM_DEBUG__
 524                                                   | DM_BLOCK_DEBUG
 525 #endif
 526                                                   ;
 527                } else dm->size &= DM_BLOCK_MASK;
 528
 529                info_block->blocks++;
 530                info_block->free -= dm->size;
 531                if( pseg ) *pseg = (block - DOSMEM_MemoryBase(hModule)) >> 4;
 532 #ifdef __DOSMEM_DEBUG__
 533                dm->size |= DM_BLOCK_DEBUG;
 534 #endif
 535                break;
 536            }
 537            dm = next;
 538        }
 539        else dm = NEXT_BLOCK(dm);
 540    }
 541    return (LPVOID)block;
 542 }
 543
 544 /***********************************************************************
 545  *           DOSMEM_FreeBlock
 546  */
 547 BOOL DOSMEM_FreeBlock(HMODULE16 hModule, void* ptr)
 548 {
 549    dosmem_info  *info_block = DOSMEM_InfoBlock(hModule);
 550
 551    if( ptr >= (void*)(((char*)DOSMEM_RootBlock(hModule)) + sizeof(dosmem_entry)) &&
 552        ptr < (void*)DOSMEM_MemoryTop(hModule) && !((((char*)ptr)
 553                   - DOSMEM_MemoryBase(hModule)) & 0xf) )
 554    {
 555        dosmem_entry  *dm = (dosmem_entry*)(((char*)ptr) - sizeof(dosmem_entry));
 556
 557        if( !(dm->size & (DM_BLOCK_FREE | DM_BLOCK_TERMINAL))
 558 #ifdef __DOSMEM_DEBUG__
 559          && ((dm->size & DM_BLOCK_DEBUG) == DM_BLOCK_DEBUG )
 560 #endif
 561          )
 562        {
 563              info_block->blocks--;
 564              info_block->free += dm->size;
 565
 566              dm->size |= DM_BLOCK_FREE;
 567              return TRUE;
 568        }
 569    }
 570    return FALSE;
 571 }
 572
 573 /***********************************************************************
 574  *           DOSMEM_ResizeBlock
 575  */
 576 LPVOID DOSMEM_ResizeBlock(HMODULE16 hModule, void* ptr, UINT size, UINT16* pseg)
 577 {
 578    char         *block = NULL;
 579    dosmem_info  *info_block = DOSMEM_InfoBlock(hModule);
 580
 581    if( ptr >= (void*)(((char*)DOSMEM_RootBlock(hModule)) + sizeof(dosmem_entry)) &&
 582        ptr < (void*)DOSMEM_MemoryTop(hModule) && !((((char*)ptr)
 583                   - DOSMEM_MemoryBase(hModule)) & 0xf) )
 584    {
 585        dosmem_entry  *dm = (dosmem_entry*)(((char*)ptr) - sizeof(dosmem_entry));
 586
 587        if( pseg ) *pseg = ((char*)ptr - DOSMEM_MemoryBase(hModule)) >> 4;
 588
 589        if( !(dm->size & (DM_BLOCK_FREE | DM_BLOCK_TERMINAL))
 590          )
 591        {
 592              dosmem_entry  *next = NEXT_BLOCK(dm);
 593              UINT blocksize, orgsize = dm->size & DM_BLOCK_MASK;
 594
 595              while( next->size & DM_BLOCK_FREE ) /* collapse free blocks */
 596              {
 597                  dm->size += sizeof(dosmem_entry) + (next->size & DM_BLOCK_MASK);
 598                  next->size = (DM_BLOCK_FREE | DM_BLOCK_TERMINAL);
 599                  next = NEXT_BLOCK(dm);
 600              }
 601
 602              blocksize = dm->size & DM_BLOCK_MASK;
 603              if (blocksize >= size)
 604              {
 605                  block = ((char*)dm) + sizeof(dosmem_entry);
 606                  if( blocksize - size > 0x20 )
 607                  {
 608                      /* split dm so that the next one stays
 609                       * paragraph-aligned (and next gains free bit) */
 610
 611                      dm->size = (((size + 0xf + sizeof(dosmem_entry)) & ~0xf) -
 612                                                 sizeof(dosmem_entry));
 613                      next = (dosmem_entry*)(((char*)dm) +
 614                              sizeof(dosmem_entry) + dm->size);
 615                      next->size = (blocksize - (dm->size +
 616                              sizeof(dosmem_entry))) | DM_BLOCK_FREE
 617                                                     ;
 618                  } else dm->size &= DM_BLOCK_MASK;
 619
 620                  info_block->free += orgsize - dm->size;
 621              } else {
 622                  /* the collapse didn't help, try getting a new block */
 623                  block = DOSMEM_GetBlock(hModule, size, pseg);
 624                  if (block) {
 625                      /* we got one, copy the old data there (we do need to, right?) */
 626                      memcpy(block, ((char*)dm) + sizeof(dosmem_entry),
 627                                    (size<orgsize) ? size : orgsize);
 628                      /* free old block */
 629                      info_block->blocks--;
 630                      info_block->free += dm->size;
 631
 632                      dm->size |= DM_BLOCK_FREE;
 633                  } else {
 634                      /* and Bill Gates said 640K should be enough for everyone... */
 635
 636                      /* need to split original and collapsed blocks apart again,
 637                       * and free the collapsed blocks again, before exiting */
 638                      if( blocksize - orgsize > 0x20 )
 639                      {
 640                          /* split dm so that the next one stays
 641                           * paragraph-aligned (and next gains free bit) */
 642
 643                          dm->size = (((orgsize + 0xf + sizeof(dosmem_entry)) & ~0xf) -
 644                                                        sizeof(dosmem_entry));
 645                          next = (dosmem_entry*)(((char*)dm) +
 646                                  sizeof(dosmem_entry) + dm->size);
 647                          next->size = (blocksize - (dm->size +
 648                                  sizeof(dosmem_entry))) | DM_BLOCK_FREE
 649                                                         ;
 650                      } else dm->size &= DM_BLOCK_MASK;
 651                  }
 652              }
 653        }
 654    }
 655    return (LPVOID)block;
 656 }
 657
 658
 659 /***********************************************************************
 660  *           DOSMEM_Available
 661  */
 662 UINT DOSMEM_Available(HMODULE16 hModule)
 663 {
 664    UINT          blocksize, available = 0;
 665    dosmem_entry *dm;
 666
 667    dm = DOSMEM_RootBlock(hModule);
 668
 669    while (dm && dm->size != DM_BLOCK_TERMINAL)
 670    {
 671 #ifdef __DOSMEM_DEBUG__
 672        if( (dm->size & DM_BLOCK_DEBUG) != DM_BLOCK_DEBUG )
 673        {
 674             WARN_(dosmem)("MCB overrun! [prev = 0x%08x]\n", 4 + (UINT)prev);
 675             return NULL;
 676        }
 677        prev = dm;
 678 #endif
 679        if( dm->size & DM_BLOCK_FREE )
 680        {
 681            dosmem_entry  *next = NEXT_BLOCK(dm);
 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 > available ) available = blocksize;
 692            dm = next;
 693        }
 694        else dm = NEXT_BLOCK(dm);
 695    }
 696    return available;
 697 }
 698
 699
 700 /***********************************************************************
 701  *           DOSMEM_MapLinearToDos
 702  *
 703  * Linear address to the DOS address space.
 704  */
 705 UINT DOSMEM_MapLinearToDos(LPVOID ptr)
 706 {
 707     if (((char*)ptr >= DOSMEM_MemoryBase(0)) &&
 708         ((char*)ptr < DOSMEM_MemoryBase(0) + 0x100000))
 709           return (UINT)ptr - (UINT)DOSMEM_MemoryBase(0);
 710     return (UINT)ptr;
 711 }
 712
 713
 714 /***********************************************************************
 715  *           DOSMEM_MapDosToLinear
 716  *
 717  * DOS linear address to the linear address space.
 718  */
 719 LPVOID DOSMEM_MapDosToLinear(UINT ptr)
 720 {
 721     if (ptr < 0x100000) return (LPVOID)(ptr + (UINT)DOSMEM_MemoryBase(0));
 722     return (LPVOID)ptr;
 723 }
 724
 725
 726 /***********************************************************************
 727  *           DOSMEM_MapRealToLinear
 728  *
 729  * Real mode DOS address into a linear pointer
 730  */
 731 LPVOID DOSMEM_MapRealToLinear(DWORD x)
 732 {
 733    LPVOID       lin;
 734
 735    lin=DOSMEM_MemoryBase(0)+(x&0xffff)+(((x&0xffff0000)>>16)*16);
 736    TRACE_(selector)("(0x%08lx) returns 0x%p.\n",
 737                     x,lin );
 738    return lin;
 739 }
 740
 741 /***********************************************************************
 742  *           DOSMEM_AllocSelector
 743  *
 744  * Allocates a protected mode selector for a realmode segment.
 745  */
 746 WORD DOSMEM_AllocSelector(WORD realsel)
 747 {
 748         HMODULE16 hModule = GetModuleHandle16("KERNEL");
 749         WORD    sel;
 750
 751         sel=GLOBAL_CreateBlock(
 752                 GMEM_FIXED,DOSMEM_dosmem+realsel*16,0x10000,
 753                 hModule,FALSE,FALSE,FALSE,NULL
 754         );
 755         TRACE_(selector)("(0x%04x) returns 0x%04x.\n",
 756                 realsel,sel
 757         );
 758         return sel;
 759 }
 760