msdos/dosmem.c

   1 /*
   2  * DOS memory emulation
   3  *
   4  * Copyright 1995 Alexandre Julliard
   5  * Copyright 1996 Marcus Meissner
   6  *
   7  * This library is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * This library is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with this library; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  */
  21
  22 #include "config.h"
  23 #include "wine/port.h"
  24
  25 #include <signal.h>
  26 #include <stdlib.h>
  27 #include <string.h>
  28 #include <sys/types.h>
  29 #ifdef HAVE_SYS_MMAN_H
  30 # include <sys/mman.h>
  31 #endif
  32
  33 #include <time.h>
  34 #ifdef HAVE_SYS_TIME_H
  35 # include <sys/time.h>
  36 #endif
  37
  38 #include "winbase.h"
  39 #include "wine/winbase16.h"
  40
  41 #include "global.h"
  42 #include "selectors.h"
  43 #include "miscemu.h"
  44 #include "wine/debug.h"
  45
  46 WINE_DEFAULT_DEBUG_CHANNEL(dosmem);
  47 WINE_DECLARE_DEBUG_CHANNEL(selector);
  48
  49 WORD DOSMEM_0000H;        /* segment at 0:0 */
  50 WORD DOSMEM_BiosDataSeg;  /* BIOS data segment at 0x40:0 */
  51 WORD DOSMEM_BiosSysSeg;   /* BIOS ROM segment at 0xf000:0 */
  52
  53 /* use 2 low bits of 'size' for the housekeeping */
  54
  55 #define DM_BLOCK_DEBUG          0xABE00000
  56 #define DM_BLOCK_TERMINAL       0x00000001
  57 #define DM_BLOCK_FREE           0x00000002
  58 #define DM_BLOCK_MASK           0x001FFFFC
  59
  60 /*
  61 #define __DOSMEM_DEBUG__
  62  */
  63
  64 typedef struct {
  65    unsigned     size;
  66 } dosmem_entry;
  67
  68 typedef struct {
  69   unsigned      blocks;
  70   unsigned      free;
  71 } dosmem_info;
  72
  73 #define NEXT_BLOCK(block) \
  74         (dosmem_entry*)(((char*)(block)) + \
  75          sizeof(dosmem_entry) + ((block)->size & DM_BLOCK_MASK))
  76
  77 #define VM_STUB(x) (0x90CF00CD|(x<<8)) /* INT x; IRET; NOP */
  78 #define VM_STUB_SEGMENT 0xf000         /* BIOS segment */
  79
  80 /* DOS memory base */
  81 static char *DOSMEM_dosmem;
  82 /* DOS system base (for interrupt vector table and BIOS data area)
  83  * ...should in theory (i.e. Windows) be equal to DOSMEM_dosmem (NULL),
  84  * but is normally set to 0xf0000 in Wine to allow trapping of NULL pointers,
  85  * and only relocated to NULL when absolutely necessary */
  86 static char *DOSMEM_sysmem;
  87
  88 /* Start of DOS conventional memory */
  89 static char *DOSMEM_membase;
  90
  91 static void DOSMEM_InitMemory(void);
  92
  93 /***********************************************************************
  94  *           DOSMEM_MemoryTop
  95  *
  96  * Gets the DOS memory top.
  97  */
  98 static char *DOSMEM_MemoryTop(void)
  99 {
 100     return DOSMEM_dosmem+0x9FFFC; /* 640K */
 101 }
 102
 103 /***********************************************************************
 104  *           DOSMEM_InfoBlock
 105  *
 106  * Gets the DOS memory info block.
 107  */
 108 static dosmem_info *DOSMEM_InfoBlock(void)
 109 {
 110     if (!DOSMEM_membase)
 111     {
 112         DWORD         reserve;
 113
 114         /*
 115          * Reserve either:
 116          * - lowest 64k for NULL pointer catching (Win16)
 117          * - lowest 1k for interrupt handlers and
 118          *   another 0.5k for BIOS, DOS and intra-application
 119          *   areas (DOS)
 120          */
 121         if (DOSMEM_dosmem != DOSMEM_sysmem)
 122             reserve = 0x10000; /* 64k */
 123         else
 124             reserve = 0x600; /* 1.5k */
 125
 126         /*
 127          * Round to paragraph boundary in order to make
 128          * sure the alignment is correct.
 129          */
 130         reserve = ((reserve + 15) >> 4) << 4;
 131
 132         /*
 133          * Set DOS memory base and initialize conventional memory.
 134          */
 135         DOSMEM_membase = DOSMEM_dosmem + reserve;
 136         DOSMEM_InitMemory();
 137     }
 138
 139     return (dosmem_info*)DOSMEM_membase;
 140 }
 141
 142 /***********************************************************************
 143  *           DOSMEM_RootBlock
 144  *
 145  * Gets the DOS memory root block.
 146  */
 147 static dosmem_entry *DOSMEM_RootBlock(void)
 148 {
 149     /* first block has to be paragraph-aligned */
 150     return (dosmem_entry*)(((char*)DOSMEM_InfoBlock()) +
 151                            ((((sizeof(dosmem_info) + 0xf) & ~0xf) - sizeof(dosmem_entry))));
 152 }
 153
 154 /***********************************************************************
 155  *           DOSMEM_FillIsrTable
 156  *
 157  * Fill the interrupt table with fake BIOS calls to BIOSSEG (0xf000).
 158  *
 159  * NOTES:
 160  * Linux normally only traps INTs performed from or destined to BIOSSEG
 161  * for us to handle, if the int_revectored table is empty. Filling the
 162  * interrupt table with calls to INT stubs in BIOSSEG allows DOS programs
 163  * to hook interrupts, as well as use their familiar retf tricks to call
 164  * them, AND let Wine handle any unhooked interrupts transparently.
 165  */
 166 static void DOSMEM_FillIsrTable(void)
 167 {
 168     SEGPTR *isr = (SEGPTR*)DOSMEM_sysmem;
 169     int x;
 170
 171     for (x=0; x<256; x++) isr[x]=MAKESEGPTR(VM_STUB_SEGMENT,x*4);
 172 }
 173
 174 static void DOSMEM_MakeIsrStubs(void)
 175 {
 176     DWORD *stub = (DWORD*)(DOSMEM_dosmem + (VM_STUB_SEGMENT << 4));
 177     int x;
 178
 179     for (x=0; x<256; x++) stub[x]=VM_STUB(x);
 180 }
 181
 182 static BIOSDATA * DOSMEM_BiosData(void)
 183 {
 184     return (BIOSDATA *)(DOSMEM_sysmem + 0x400);
 185 }
 186
 187 /**********************************************************************
 188  *          DOSMEM_GetTicksSinceMidnight
 189  *
 190  * Return number of clock ticks since midnight.
 191  */
 192 static DWORD DOSMEM_GetTicksSinceMidnight(void)
 193 {
 194     struct tm *bdtime;
 195     struct timeval tvs;
 196     time_t seconds;
 197
 198     /* This should give us the (approximately) correct
 199      * 18.206 clock ticks per second since midnight.
 200      */
 201     gettimeofday( &tvs, NULL );
 202     seconds = tvs.tv_sec;
 203     bdtime = localtime( &seconds );
 204     return (((bdtime->tm_hour * 3600 + bdtime->tm_min * 60 +
 205               bdtime->tm_sec) * 18206) / 1000) +
 206                   (tvs.tv_usec / 54927);
 207 }
 208
 209 /***********************************************************************
 210  *           DOSMEM_FillBiosSegments
 211  *
 212  * Fill the BIOS data segment with dummy values.
 213  */
 214 static void DOSMEM_FillBiosSegments(void)
 215 {
 216     BYTE *pBiosSys = DOSMEM_dosmem + 0xf0000;
 217     BYTE *pBiosROMTable = pBiosSys+0xe6f5;
 218     BIOS_EXTRA *extra = (BIOS_EXTRA *)(DOSMEM_dosmem + (int)BIOS_EXTRA_PTR);
 219     BIOSDATA *pBiosData = DOSMEM_BiosData();
 220
 221     /* Supported VESA mode, see int10.c */
 222     WORD ConstVesaModeList[]={0x00,0x01,0x02,0x03,0x07,0x0D,0x0E,0x10,0x12,0x13,
 223                               0x100,0x101,0x102,0x103,0x104,0x105,0x106,0x107,0x10D,0x10E,
 224                               0x10F,0x110,0x111,0x112,0x113,0x114,0x115,0x116,0x117,0x118,
 225                               0x119,0x11A,0x11B,0xFFFF};
 226     char * ConstVesaString = "WINE SVGA BOARD";
 227     int i;
 228
 229     VIDEOFUNCTIONALITY *pVidFunc = &extra->vid_func;
 230     VIDEOSTATE *pVidState = &extra->vid_state;
 231     VESAINFO *pVesaInfo = &extra->vesa_info;
 232     char * VesaString = extra->vesa_string;
 233     WORD * VesaModeList = extra->vesa_modes;
 234
 235       /* Clear all unused values */
 236     memset( pBiosData, 0, sizeof(*pBiosData) );
 237     memset( pVidFunc,  0, sizeof(*pVidFunc ) );
 238     memset( pVidState, 0, sizeof(*pVidState) );
 239     memset( pVesaInfo, 0, sizeof(*pVesaInfo) );
 240
 241     /* FIXME: should check the number of configured drives and ports */
 242     pBiosData->Com1Addr             = 0x3f8;
 243     pBiosData->Com2Addr             = 0x2f8;
 244     pBiosData->Lpt1Addr             = 0x378;
 245     pBiosData->Lpt2Addr             = 0x278;
 246     pBiosData->InstalledHardware    = 0x5463;
 247     pBiosData->MemSize              = 640;
 248     pBiosData->NextKbdCharPtr       = 0x1e;
 249     pBiosData->FirstKbdCharPtr      = 0x1e;
 250     pBiosData->VideoMode            = 3;
 251     pBiosData->VideoColumns         = 80;
 252     pBiosData->VideoPageSize        = 80 * 25 * 2;
 253     pBiosData->VideoPageStartAddr   = 0xb800;
 254     pBiosData->VideoCtrlAddr        = 0x3d4;
 255     pBiosData->Ticks                = DOSMEM_GetTicksSinceMidnight();
 256     pBiosData->NbHardDisks          = 2;
 257     pBiosData->KbdBufferStart       = 0x1e;
 258     pBiosData->KbdBufferEnd         = 0x3e;
 259     pBiosData->RowsOnScreenMinus1   = 24;
 260     pBiosData->BytesPerChar         = 0x10;
 261     pBiosData->ModeOptions          = 0x64;
 262     pBiosData->FeatureBitsSwitches  = 0xf9;
 263     pBiosData->VGASettings          = 0x51;
 264     pBiosData->DisplayCombination   = 0x08;
 265     pBiosData->DiskDataRate         = 0;
 266
 267     /* fill ROM configuration table (values from Award) */
 268     *(pBiosROMTable+0x0)        = 0x08; /* number of bytes following LO */
 269     *(pBiosROMTable+0x1)        = 0x00; /* number of bytes following HI */
 270     *(pBiosROMTable+0x2)        = 0xfc; /* model */
 271     *(pBiosROMTable+0x3)        = 0x01; /* submodel */
 272     *(pBiosROMTable+0x4)        = 0x00; /* BIOS revision */
 273     *(pBiosROMTable+0x5)        = 0x74; /* feature byte 1 */
 274     *(pBiosROMTable+0x6)        = 0x00; /* feature byte 2 */
 275     *(pBiosROMTable+0x7)        = 0x00; /* feature byte 3 */
 276     *(pBiosROMTable+0x8)        = 0x00; /* feature byte 4 */
 277     *(pBiosROMTable+0x9)        = 0x00; /* feature byte 5 */
 278
 279
 280     for (i = 0; i < 7; i++)
 281         pVidFunc->ModeSupport[i] = 0xff;
 282
 283     pVidFunc->ScanlineSupport     = 7;
 284     pVidFunc->NumberCharBlocks    = 0;
 285     pVidFunc->ActiveCharBlocks    = 0;
 286     pVidFunc->MiscFlags           = 0x8ff;
 287     pVidFunc->SavePointerFlags    = 0x3f;
 288
 289                                     /* FIXME: always real mode ? */
 290     pVidState->StaticFuncTable    = BIOS_EXTRA_SEGPTR + offsetof(BIOS_EXTRA,vid_func);
 291     pVidState->VideoMode          = pBiosData->VideoMode; /* needs updates! */
 292     pVidState->NumberColumns      = pBiosData->VideoColumns; /* needs updates! */
 293     pVidState->RegenBufLen        = 0;
 294     pVidState->RegenBufAddr       = 0;
 295
 296     for (i = 0; i < 8; i++)
 297         pVidState->CursorPos[i] = 0;
 298
 299     pVidState->CursorType         = 0x0a0b;  /* start/end line */
 300     pVidState->ActivePage         = 0;
 301     pVidState->CRTCPort           = 0x3da;
 302     pVidState->Port3x8            = 0;
 303     pVidState->Port3x9            = 0;
 304     pVidState->NumberRows         = 23;     /* number of rows - 1 */
 305     pVidState->BytesPerChar       = 0x10;
 306     pVidState->DCCActive          = pBiosData->DisplayCombination;
 307     pVidState->DCCAlternate       = 0;
 308     pVidState->NumberColors       = 16;
 309     pVidState->NumberPages        = 1;
 310     pVidState->NumberScanlines    = 3; /* (0,1,2,3) = (200,350,400,480) */
 311     pVidState->CharBlockPrimary   = 0;
 312     pVidState->CharBlockSecondary = 0;
 313     pVidState->MiscFlags =
 314                            (pBiosData->VGASettings & 0x0f)
 315                          | ((pBiosData->ModeOptions & 1) << 4); /* cursor emulation */
 316     pVidState->NonVGASupport      = 0;
 317     pVidState->VideoMem           = (pBiosData->ModeOptions & 0x60 >> 5);
 318     pVidState->SavePointerState   = 0;
 319     pVidState->DisplayStatus      = 4;
 320
 321     /* SVGA structures */
 322     pVesaInfo->Signature          = *(DWORD*)"VESA";
 323     pVesaInfo->Major              = 2;
 324     pVesaInfo->Minor              = 0;
 325                                     /* FIXME: always real mode ? */
 326     pVesaInfo->StaticVendorString = BIOS_EXTRA_SEGPTR + offsetof(BIOS_EXTRA,vesa_string);
 327     pVesaInfo->CapabilitiesFlags  = 0xfffffffd; /* FIXME: not really supported */
 328                                     /* FIXME: always real mode ? */
 329     pVesaInfo->StaticModeList     = BIOS_EXTRA_SEGPTR + offsetof(BIOS_EXTRA,vesa_modes);
 330
 331     strcpy(VesaString,ConstVesaString);
 332     memcpy(VesaModeList,ConstVesaModeList,sizeof(ConstVesaModeList));
 333
 334     /* BIOS date string */
 335     strcpy((char *)pBiosSys+0xfff5, "13/01/99");
 336
 337     /* BIOS ID */
 338     *(pBiosSys+0xfffe) = 0xfc;
 339 }
 340
 341 /***********************************************************************
 342  *           DOSMEM_InitMemory
 343  *
 344  * Initialises the DOS memory structures.
 345  */
 346 static void DOSMEM_InitMemory(void)
 347 {
 348     dosmem_info*        info_block = DOSMEM_InfoBlock();
 349     dosmem_entry*       root_block = DOSMEM_RootBlock();
 350     dosmem_entry*       dm;
 351
 352     root_block->size = DOSMEM_MemoryTop() - (((char*)root_block) + sizeof(dosmem_entry));
 353
 354     info_block->blocks = 0;
 355     info_block->free = root_block->size;
 356
 357     dm = NEXT_BLOCK(root_block);
 358     dm->size = DM_BLOCK_TERMINAL;
 359     root_block->size |= DM_BLOCK_FREE
 360 #ifdef __DOSMEM_DEBUG__
 361                      | DM_BLOCK_DEBUG
 362 #endif
 363                      ;
 364
 365     TRACE( "DOS conventional memory initialized, %d bytes free.\n",
 366            DOSMEM_Available() );
 367 }
 368
 369
 370 /**********************************************************************
 371  *              setup_dos_mem
 372  *
 373  * Setup the first megabyte for DOS memory access
 374  */
 375 static void setup_dos_mem( int dos_init )
 376 {
 377     int sys_offset = 0;
 378     int page_size = getpagesize();
 379     void *addr = wine_anon_mmap( (void *)page_size, 0x110000-page_size,
 380                                  PROT_READ | PROT_WRITE | PROT_EXEC, 0 );
 381     if (addr == (void *)page_size)  /* we got what we wanted */
 382     {
 383         /* now map from address 0 */
 384         addr = wine_anon_mmap( NULL, 0x110000, PROT_READ | PROT_WRITE | PROT_EXEC, MAP_FIXED );
 385         if (addr)
 386         {
 387             ERR("MAP_FIXED failed at address 0 for DOS address space\n" );
 388             ExitProcess(1);
 389         }
 390
 391         /* inform the memory manager that there is a mapping here */
 392         VirtualAlloc( addr, 0x110000, MEM_RESERVE | MEM_SYSTEM, PAGE_EXECUTE_READWRITE );
 393
 394         /* protect the first 64K to catch NULL pointers */
 395         if (!dos_init)
 396         {
 397             VirtualProtect( addr, 0x10000, PAGE_NOACCESS, NULL );
 398             /* move the BIOS and ISR area from 0x00000 to 0xf0000 */
 399             sys_offset += 0xf0000;
 400         }
 401     }
 402     else
 403     {
 404         ERR("Cannot use first megabyte for DOS address space, please report\n" );
 405         if (dos_init) ExitProcess(1);
 406         /* allocate the DOS area somewhere else */
 407         addr = VirtualAlloc( NULL, 0x110000, MEM_COMMIT, PAGE_EXECUTE_READWRITE );
 408         if (!addr)
 409         {
 410             ERR( "Cannot allocate DOS memory\n" );
 411             ExitProcess(1);
 412         }
 413     }
 414     DOSMEM_dosmem = addr;
 415     DOSMEM_sysmem = (char*)addr + sys_offset;
 416 }
 417
 418
 419 /***********************************************************************
 420  *           DOSMEM_Init
 421  *
 422  * Create the dos memory segments, and store them into the KERNEL
 423  * exported values.
 424  */
 425 BOOL DOSMEM_Init(BOOL dos_init)
 426 {
 427     static int already_done, already_mapped;
 428
 429     if (!already_done)
 430     {
 431         setup_dos_mem( dos_init );
 432
 433         DOSMEM_0000H = GLOBAL_CreateBlock( GMEM_FIXED, DOSMEM_sysmem,
 434                                            0x10000, 0, WINE_LDT_FLAGS_DATA );
 435         DOSMEM_BiosDataSeg = GLOBAL_CreateBlock(GMEM_FIXED,DOSMEM_sysmem + 0x400,
 436                                                 0x100, 0, WINE_LDT_FLAGS_DATA );
 437         DOSMEM_BiosSysSeg = GLOBAL_CreateBlock(GMEM_FIXED,DOSMEM_dosmem+0xf0000,
 438                                                0x10000, 0, WINE_LDT_FLAGS_DATA );
 439         DOSMEM_FillBiosSegments();
 440         DOSMEM_FillIsrTable();
 441         already_done = 1;
 442     }
 443     else if (dos_init && !already_mapped)
 444     {
 445         if (DOSMEM_dosmem)
 446         {
 447             ERR( "Needs access to the first megabyte for DOS mode\n" );
 448             ExitProcess(1);
 449         }
 450         MESSAGE( "Warning: unprotecting the first 64KB of memory to allow real-mode calls.\n"
 451                  "         NULL pointer accesses will no longer be caught.\n" );
 452         VirtualProtect( NULL, 0x10000, PAGE_EXECUTE_READWRITE, NULL );
 453         /* copy the BIOS and ISR area down */
 454         memcpy( DOSMEM_dosmem, DOSMEM_sysmem, 0x400 + 0x100 );
 455         DOSMEM_sysmem = DOSMEM_dosmem;
 456         SetSelectorBase( DOSMEM_0000H, 0 );
 457         SetSelectorBase( DOSMEM_BiosDataSeg, 0x400 );
 458         /* we may now need the actual interrupt stubs, and since we've just moved the
 459          * interrupt vector table away, we can fill the area with stubs instead... */
 460         DOSMEM_MakeIsrStubs();
 461         already_mapped = 1;
 462     }
 463     return TRUE;
 464 }
 465
 466
 467 /***********************************************************************
 468  *           DOSMEM_Tick
 469  *
 470  * Increment the BIOS tick counter. Called by timer signal handler.
 471  */
 472 void DOSMEM_Tick( WORD timer )
 473 {
 474     BIOSDATA *pBiosData = DOSMEM_BiosData();
 475     if (pBiosData) pBiosData->Ticks++;
 476 }
 477
 478 /***********************************************************************
 479  *           DOSMEM_GetBlock
 480  *
 481  * Carve a chunk of the DOS memory block (without selector).
 482  */
 483 LPVOID DOSMEM_GetBlock(UINT size, UINT16* pseg)
 484 {
 485    UINT          blocksize;
 486    char         *block = NULL;
 487    dosmem_info  *info_block = DOSMEM_InfoBlock();
 488    dosmem_entry *dm;
 489 #ifdef __DOSMEM_DEBUG_
 490    dosmem_entry *prev = NULL;
 491 #endif
 492
 493    if( size > info_block->free ) return NULL;
 494    dm = DOSMEM_RootBlock();
 495
 496    while (dm && dm->size != DM_BLOCK_TERMINAL)
 497    {
 498 #ifdef __DOSMEM_DEBUG__
 499        if( (dm->size & DM_BLOCK_DEBUG) != DM_BLOCK_DEBUG )
 500        {
 501             WARN("MCB overrun! [prev = 0x%08x]\n", 4 + (UINT)prev);
 502             return NULL;
 503        }
 504        prev = dm;
 505 #endif
 506        if( dm->size & DM_BLOCK_FREE )
 507        {
 508            dosmem_entry  *next = NEXT_BLOCK(dm);
 509
 510            while( next->size & DM_BLOCK_FREE ) /* collapse free blocks */
 511            {
 512                dm->size += sizeof(dosmem_entry) + (next->size & DM_BLOCK_MASK);
 513                next->size = (DM_BLOCK_FREE | DM_BLOCK_TERMINAL);
 514                next = NEXT_BLOCK(dm);
 515            }
 516
 517            blocksize = dm->size & DM_BLOCK_MASK;
 518            if( blocksize >= size )
 519            {
 520                block = ((char*)dm) + sizeof(dosmem_entry);
 521                if( blocksize - size > 0x20 )
 522                {
 523                    /* split dm so that the next one stays
 524                     * paragraph-aligned (and dm loses free bit) */
 525
 526                    dm->size = (((size + 0xf + sizeof(dosmem_entry)) & ~0xf) -
 527                                               sizeof(dosmem_entry));
 528                    next = (dosmem_entry*)(((char*)dm) +
 529                            sizeof(dosmem_entry) + dm->size);
 530                    next->size = (blocksize - (dm->size +
 531                            sizeof(dosmem_entry))) | DM_BLOCK_FREE
 532 #ifdef __DOSMEM_DEBUG__
 533                                                   | DM_BLOCK_DEBUG
 534 #endif
 535                                                   ;
 536                } else dm->size &= DM_BLOCK_MASK;
 537
 538                info_block->blocks++;
 539                info_block->free -= dm->size;
 540                if( pseg ) *pseg = (block - DOSMEM_dosmem) >> 4;
 541 #ifdef __DOSMEM_DEBUG__
 542                dm->size |= DM_BLOCK_DEBUG;
 543 #endif
 544                break;
 545            }
 546            dm = next;
 547        }
 548        else dm = NEXT_BLOCK(dm);
 549    }
 550    return (LPVOID)block;
 551 }
 552
 553 /***********************************************************************
 554  *           DOSMEM_FreeBlock
 555  */
 556 BOOL DOSMEM_FreeBlock(void* ptr)
 557 {
 558    dosmem_info  *info_block = DOSMEM_InfoBlock();
 559
 560    if( ptr >= (void*)(((char*)DOSMEM_RootBlock()) + sizeof(dosmem_entry)) &&
 561        ptr < (void*)DOSMEM_MemoryTop() && !((((char*)ptr)
 562                   - DOSMEM_dosmem) & 0xf) )
 563    {
 564        dosmem_entry  *dm = (dosmem_entry*)(((char*)ptr) - sizeof(dosmem_entry));
 565
 566        if( !(dm->size & (DM_BLOCK_FREE | DM_BLOCK_TERMINAL))
 567 #ifdef __DOSMEM_DEBUG__
 568          && ((dm->size & DM_BLOCK_DEBUG) == DM_BLOCK_DEBUG )
 569 #endif
 570          )
 571        {
 572              info_block->blocks--;
 573              info_block->free += dm->size;
 574
 575              dm->size |= DM_BLOCK_FREE;
 576              return TRUE;
 577        }
 578    }
 579    return FALSE;
 580 }
 581
 582 /***********************************************************************
 583  *           DOSMEM_ResizeBlock
 584  */
 585 LPVOID DOSMEM_ResizeBlock(void* ptr, UINT size, UINT16* pseg)
 586 {
 587    char         *block = NULL;
 588    dosmem_info  *info_block = DOSMEM_InfoBlock();
 589
 590    if( ptr >= (void*)(((char*)DOSMEM_RootBlock()) + sizeof(dosmem_entry)) &&
 591        ptr < (void*)DOSMEM_MemoryTop() && !((((char*)ptr)
 592                   - DOSMEM_dosmem) & 0xf) )
 593    {
 594        dosmem_entry  *dm = (dosmem_entry*)(((char*)ptr) - sizeof(dosmem_entry));
 595
 596        if( pseg ) *pseg = ((char*)ptr - DOSMEM_dosmem) >> 4;
 597
 598        if( !(dm->size & (DM_BLOCK_FREE | DM_BLOCK_TERMINAL))
 599          )
 600        {
 601              dosmem_entry  *next = NEXT_BLOCK(dm);
 602              UINT blocksize, orgsize = dm->size & DM_BLOCK_MASK;
 603
 604              while( next->size & DM_BLOCK_FREE ) /* collapse free blocks */
 605              {
 606                  dm->size += sizeof(dosmem_entry) + (next->size & DM_BLOCK_MASK);
 607                  next->size = (DM_BLOCK_FREE | DM_BLOCK_TERMINAL);
 608                  next = NEXT_BLOCK(dm);
 609              }
 610
 611              blocksize = dm->size & DM_BLOCK_MASK;
 612              if (blocksize >= size)
 613              {
 614                  block = ((char*)dm) + sizeof(dosmem_entry);
 615                  if( blocksize - size > 0x20 )
 616                  {
 617                      /* split dm so that the next one stays
 618                       * paragraph-aligned (and next gains free bit) */
 619
 620                      dm->size = (((size + 0xf + sizeof(dosmem_entry)) & ~0xf) -
 621                                                 sizeof(dosmem_entry));
 622                      next = (dosmem_entry*)(((char*)dm) +
 623                              sizeof(dosmem_entry) + dm->size);
 624                      next->size = (blocksize - (dm->size +
 625                              sizeof(dosmem_entry))) | DM_BLOCK_FREE
 626                                                     ;
 627                  } else dm->size &= DM_BLOCK_MASK;
 628
 629                  info_block->free += orgsize - dm->size;
 630              } else {
 631                  /* the collapse didn't help, try getting a new block */
 632                  block = DOSMEM_GetBlock(size, pseg);
 633                  if (block) {
 634                      /* we got one, copy the old data there (we do need to, right?) */
 635                      memcpy(block, ((char*)dm) + sizeof(dosmem_entry),
 636                                    (size<orgsize) ? size : orgsize);
 637                      /* free old block */
 638                      info_block->blocks--;
 639                      info_block->free += dm->size;
 640
 641                      dm->size |= DM_BLOCK_FREE;
 642                  } else {
 643                      /* and Bill Gates said 640K should be enough for everyone... */
 644
 645                      /* need to split original and collapsed blocks apart again,
 646                       * and free the collapsed blocks again, before exiting */
 647                      if( blocksize - orgsize > 0x20 )
 648                      {
 649                          /* split dm so that the next one stays
 650                           * paragraph-aligned (and next gains free bit) */
 651
 652                          dm->size = (((orgsize + 0xf + sizeof(dosmem_entry)) & ~0xf) -
 653                                                        sizeof(dosmem_entry));
 654                          next = (dosmem_entry*)(((char*)dm) +
 655                                  sizeof(dosmem_entry) + dm->size);
 656                          next->size = (blocksize - (dm->size +
 657                                  sizeof(dosmem_entry))) | DM_BLOCK_FREE
 658                                                         ;
 659                      } else dm->size &= DM_BLOCK_MASK;
 660                  }
 661              }
 662        }
 663    }
 664    return (LPVOID)block;
 665 }
 666
 667
 668 /***********************************************************************
 669  *           DOSMEM_Available
 670  */
 671 UINT DOSMEM_Available(void)
 672 {
 673    UINT          blocksize, available = 0;
 674    dosmem_entry *dm;
 675
 676    dm = DOSMEM_RootBlock();
 677
 678    while (dm && dm->size != DM_BLOCK_TERMINAL)
 679    {
 680 #ifdef __DOSMEM_DEBUG__
 681        if( (dm->size & DM_BLOCK_DEBUG) != DM_BLOCK_DEBUG )
 682        {
 683             WARN("MCB overrun! [prev = 0x%08x]\n", 4 + (UINT)prev);
 684             return NULL;
 685        }
 686        prev = dm;
 687 #endif
 688        if( dm->size & DM_BLOCK_FREE )
 689        {
 690            dosmem_entry  *next = NEXT_BLOCK(dm);
 691
 692            while( next->size & DM_BLOCK_FREE ) /* collapse free blocks */
 693            {
 694                dm->size += sizeof(dosmem_entry) + (next->size & DM_BLOCK_MASK);
 695                next->size = (DM_BLOCK_FREE | DM_BLOCK_TERMINAL);
 696                next = NEXT_BLOCK(dm);
 697            }
 698
 699            blocksize = dm->size & DM_BLOCK_MASK;
 700            if ( blocksize > available ) available = blocksize;
 701            dm = next;
 702        }
 703        else dm = NEXT_BLOCK(dm);
 704    }
 705    return available;
 706 }
 707
 708
 709 /***********************************************************************
 710  *           DOSMEM_MapLinearToDos
 711  *
 712  * Linear address to the DOS address space.
 713  */
 714 UINT DOSMEM_MapLinearToDos(LPVOID ptr)
 715 {
 716     if (((char*)ptr >= DOSMEM_dosmem) &&
 717         ((char*)ptr < DOSMEM_dosmem + 0x100000))
 718           return (UINT)ptr - (UINT)DOSMEM_dosmem;
 719     return (UINT)ptr;
 720 }
 721
 722
 723 /***********************************************************************
 724  *           DOSMEM_MapDosToLinear
 725  *
 726  * DOS linear address to the linear address space.
 727  */
 728 LPVOID DOSMEM_MapDosToLinear(UINT ptr)
 729 {
 730     if (ptr < 0x100000) return (LPVOID)(ptr + (UINT)DOSMEM_dosmem);
 731     return (LPVOID)ptr;
 732 }
 733
 734
 735 /***********************************************************************
 736  *           DOSMEM_MapRealToLinear
 737  *
 738  * Real mode DOS address into a linear pointer
 739  */
 740 LPVOID DOSMEM_MapRealToLinear(DWORD x)
 741 {
 742    LPVOID       lin;
 743
 744    lin=DOSMEM_dosmem+(x&0xffff)+(((x&0xffff0000)>>16)*16);
 745    TRACE_(selector)("(0x%08lx) returns %p.\n", x, lin );
 746    return lin;
 747 }
 748
 749 /***********************************************************************
 750  *           DOSMEM_AllocSelector
 751  *
 752  * Allocates a protected mode selector for a realmode segment.
 753  */
 754 WORD DOSMEM_AllocSelector(WORD realsel)
 755 {
 756         HMODULE16 hModule = GetModuleHandle16("KERNEL");
 757         WORD    sel;
 758
 759         sel=GLOBAL_CreateBlock( GMEM_FIXED, DOSMEM_dosmem+realsel*16, 0x10000,
 760                                 hModule, WINE_LDT_FLAGS_DATA );
 761         TRACE_(selector)("(0x%04x) returns 0x%04x.\n", realsel,sel);
 762         return sel;
 763 }