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 #ifdef HAVE_SYS_MMAN_H
  14 # include <sys/mman.h>
  15 #endif
  16
  17 #include "winbase.h"
  18 #include "wine/winbase16.h"
  19
  20 #include "global.h"
  21 #include "ldt.h"
  22 #include "selectors.h"
  23 #include "miscemu.h"
  24 #include "vga.h"
  25 #include "dosexe.h"
  26 #include "debugtools.h"
  27
  28 DEFAULT_DEBUG_CHANNEL(dosmem);
  29 DECLARE_DEBUG_CHANNEL(selector);
  30
  31 HANDLE16 DOSMEM_BiosDataSeg;  /* BIOS data segment at 0x40:0 */
  32 HANDLE16 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 /* bios area; normally at offset 0x400, but can be moved to trap NULL pointers */
  66 static void *DOSMEM_biosdata;
  67
  68 /* various real-mode code stubs */
  69 WORD DOSMEM_wrap_seg;
  70 WORD DOSMEM_xms_seg;
  71 WORD DOSMEM_dpmi_seg;
  72 WORD DOSMEM_dpmi_sel;
  73
  74 /***********************************************************************
  75  *           DOSMEM_MemoryBase
  76  *
  77  * Gets the DOS memory base.
  78  */
  79 char *DOSMEM_MemoryBase(void)
  80 {
  81     return DOSMEM_dosmem;
  82 }
  83
  84 /***********************************************************************
  85  *           DOSMEM_MemoryTop
  86  *
  87  * Gets the DOS memory top.
  88  */
  89 static char *DOSMEM_MemoryTop(void)
  90 {
  91     return DOSMEM_dosmem+0x9FFFC; /* 640K */
  92 }
  93
  94 /***********************************************************************
  95  *           DOSMEM_InfoBlock
  96  *
  97  * Gets the DOS memory info block.
  98  */
  99 static dosmem_info *DOSMEM_InfoBlock(void)
 100 {
 101     return (dosmem_info*)(DOSMEM_dosmem+0x10000); /* 64K */
 102 }
 103
 104 /***********************************************************************
 105  *           DOSMEM_RootBlock
 106  *
 107  * Gets the DOS memory root block.
 108  */
 109 static dosmem_entry *DOSMEM_RootBlock(void)
 110 {
 111     /* first block has to be paragraph-aligned */
 112     return (dosmem_entry*)(((char*)DOSMEM_InfoBlock()) +
 113                            ((((sizeof(dosmem_info) + 0xf) & ~0xf) - sizeof(dosmem_entry))));
 114 }
 115
 116 /***********************************************************************
 117  *           DOSMEM_FillIsrTable
 118  *
 119  * Fill the interrupt table with fake BIOS calls to BIOSSEG (0xf000).
 120  *
 121  * NOTES:
 122  * Linux normally only traps INTs performed from or destined to BIOSSEG
 123  * for us to handle, if the int_revectored table is empty. Filling the
 124  * interrupt table with calls to INT stubs in BIOSSEG allows DOS programs
 125  * to hook interrupts, as well as use their familiar retf tricks to call
 126  * them, AND let Wine handle any unhooked interrupts transparently.
 127  */
 128 static void DOSMEM_FillIsrTable(void)
 129 {
 130     SEGPTR *isr = (SEGPTR*)DOSMEM_dosmem;
 131     DWORD *stub = (DWORD*)((char*)isr + (VM_STUB_SEGMENT << 4));
 132     int x;
 133
 134     for (x=0; x<256; x++) isr[x]=PTR_SEG_OFF_TO_SEGPTR(VM_STUB_SEGMENT,x*4);
 135     for (x=0; x<256; x++) stub[x]=VM_STUB(x);
 136 }
 137
 138 /***********************************************************************
 139  *           DOSMEM_InitDPMI
 140  *
 141  * Allocate the global DPMI RMCB wrapper.
 142  */
 143 static void DOSMEM_InitDPMI(void)
 144 {
 145     LPSTR ptr;
 146
 147     static const char wrap_code[]={
 148      0xCD,0x31, /* int $0x31 */
 149      0xCB       /* lret */
 150     };
 151
 152     static const char enter_xms[]=
 153     {
 154         /* XMS hookable entry point */
 155         0xEB,0x03,           /* jmp entry */
 156         0x90,0x90,0x90,      /* nop;nop;nop */
 157                              /* entry: */
 158         /* real entry point */
 159         /* for simplicity, we'll just use the same hook as DPMI below */
 160         0xCD,0x31,           /* int $0x31 */
 161         0xCB                 /* lret */
 162     };
 163
 164     static const char enter_pm[]=
 165     {
 166         0x50,                /* pushw %ax */
 167         0x52,                /* pushw %dx */
 168         0x55,                /* pushw %bp */
 169         0x89,0xE5,           /* movw %sp,%bp */
 170         /* get return CS */
 171         0x8B,0x56,0x08,      /* movw 8(%bp),%dx */
 172         /* just call int 31 here to get into protected mode... */
 173         /* it'll check whether it was called from dpmi_seg... */
 174         0xCD,0x31,           /* int $0x31 */
 175         /* we are now in the context of a 16-bit relay call */
 176         /* need to fixup our stack;
 177          * 16-bit relay return address will be lost, but we won't worry quite yet */
 178         0x8E,0xD0,           /* movw %ax,%ss */
 179         0x66,0x0F,0xB7,0xE5, /* movzwl %bp,%esp */
 180         /* set return CS */
 181         0x89,0x56,0x08,      /* movw %dx,8(%bp) */
 182         0x5D,                /* popw %bp */
 183         0x5A,                /* popw %dx */
 184         0x58,                /* popw %ax */
 185         0xCB                 /* lret */
 186     };
 187
 188     ptr = DOSMEM_GetBlock( sizeof(wrap_code), &DOSMEM_wrap_seg );
 189     memcpy( ptr, wrap_code, sizeof(wrap_code) );
 190     ptr = DOSMEM_GetBlock( sizeof(enter_xms), &DOSMEM_xms_seg );
 191     memcpy( ptr, enter_xms, sizeof(enter_xms) );
 192     ptr = DOSMEM_GetBlock( sizeof(enter_pm), &DOSMEM_dpmi_seg );
 193     memcpy( ptr, enter_pm, sizeof(enter_pm) );
 194     DOSMEM_dpmi_sel = SELECTOR_AllocBlock( ptr, sizeof(enter_pm), SEGMENT_CODE, FALSE, FALSE );
 195 }
 196
 197 BIOSDATA * DOSMEM_BiosData()
 198 {
 199     return (BIOSDATA *)DOSMEM_biosdata;
 200 }
 201
 202 BYTE * DOSMEM_BiosSys()
 203 {
 204     return DOSMEM_dosmem+0xf0000;
 205 }
 206
 207 struct _DOS_LISTOFLISTS * DOSMEM_LOL()
 208 {
 209     return (struct _DOS_LISTOFLISTS *)DOSMEM_MapRealToLinear
 210       (PTR_SEG_OFF_TO_SEGPTR(HIWORD(DOS_LOLSeg),0));
 211 }
 212
 213 /***********************************************************************
 214  *           DOSMEM_FillBiosSegments
 215  *
 216  * Fill the BIOS data segment with dummy values.
 217  */
 218 static void DOSMEM_FillBiosSegments(void)
 219 {
 220     BYTE *pBiosSys = DOSMEM_BiosSys();
 221     BYTE *pBiosROMTable = pBiosSys+0xe6f5;
 222     BIOSDATA *pBiosData = DOSMEM_BiosData();
 223
 224     /* bogus 0xe0xx addresses !! Adapt int 0x10/0x1b if change needed */
 225     VIDEOFUNCTIONALITY *pVidFunc = (VIDEOFUNCTIONALITY *)(pBiosSys+0xe000);
 226     VIDEOSTATE *pVidState = (VIDEOSTATE *)(pBiosSys+0xe010);
 227     int i;
 228
 229       /* Clear all unused values */
 230     memset( pBiosData, 0, sizeof(*pBiosData) );
 231     memset( pVidFunc,  0, sizeof(*pVidFunc ) );
 232     memset( pVidState, 0, sizeof(*pVidState) );
 233
 234     /* FIXME: should check the number of configured drives and ports */
 235
 236     pBiosData->Com1Addr             = 0x3f8;
 237     pBiosData->Com2Addr             = 0x2f8;
 238     pBiosData->Lpt1Addr             = 0x378;
 239     pBiosData->Lpt2Addr             = 0x278;
 240     pBiosData->InstalledHardware    = 0x5463;
 241     pBiosData->MemSize              = 640;
 242     pBiosData->NextKbdCharPtr       = 0x1e;
 243     pBiosData->FirstKbdCharPtr      = 0x1e;
 244     pBiosData->VideoMode            = 3;
 245     pBiosData->VideoColumns         = 80;
 246     pBiosData->VideoPageSize        = 80 * 25 * 2;
 247     pBiosData->VideoPageStartAddr   = 0xb800;
 248     pBiosData->VideoCtrlAddr        = 0x3d4;
 249     pBiosData->Ticks                = INT1A_GetTicksSinceMidnight();
 250     pBiosData->NbHardDisks          = 2;
 251     pBiosData->KbdBufferStart       = 0x1e;
 252     pBiosData->KbdBufferEnd         = 0x3e;
 253     pBiosData->RowsOnScreenMinus1   = 23;
 254     pBiosData->BytesPerChar         = 0x10;
 255     pBiosData->ModeOptions          = 0x64;
 256     pBiosData->FeatureBitsSwitches  = 0xf9;
 257     pBiosData->VGASettings          = 0x51;
 258     pBiosData->DisplayCombination   = 0x08;
 259     pBiosData->DiskDataRate         = 0;
 260
 261     /* fill ROM configuration table (values from Award) */
 262     *(pBiosROMTable+0x0)        = 0x08; /* number of bytes following LO */
 263     *(pBiosROMTable+0x1)        = 0x00; /* number of bytes following HI */
 264     *(pBiosROMTable+0x2)        = 0xfc; /* model */
 265     *(pBiosROMTable+0x3)        = 0x01; /* submodel */
 266     *(pBiosROMTable+0x4)        = 0x00; /* BIOS revision */
 267     *(pBiosROMTable+0x5)        = 0x74; /* feature byte 1 */
 268     *(pBiosROMTable+0x6)        = 0x00; /* feature byte 2 */
 269     *(pBiosROMTable+0x7)        = 0x00; /* feature byte 3 */
 270     *(pBiosROMTable+0x8)        = 0x00; /* feature byte 4 */
 271     *(pBiosROMTable+0x9)        = 0x00; /* feature byte 5 */
 272
 273
 274     for (i = 0; i < 7; i++)
 275         pVidFunc->ModeSupport[i] = 0xff;
 276
 277     pVidFunc->ScanlineSupport     = 7;
 278     pVidFunc->NumberCharBlocks    = 0;
 279     pVidFunc->ActiveCharBlocks    = 0;
 280     pVidFunc->MiscFlags           = 0x8ff;
 281     pVidFunc->SavePointerFlags    = 0x3f;
 282
 283     pVidState->StaticFuncTable    = 0xf000e000;  /* FIXME: always real mode ? */
 284     pVidState->VideoMode          = pBiosData->VideoMode; /* needs updates! */
 285     pVidState->NumberColumns      = pBiosData->VideoColumns; /* needs updates! */
 286     pVidState->RegenBufLen        = 0;
 287     pVidState->RegenBufAddr       = 0;
 288
 289     for (i = 0; i < 8; i++)
 290         pVidState->CursorPos[i] = 0;
 291
 292     pVidState->CursorType         = 0x0a0b;  /* start/end line */
 293     pVidState->ActivePage         = 0;
 294     pVidState->CRTCPort           = 0x3da;
 295     pVidState->Port3x8            = 0;
 296     pVidState->Port3x9            = 0;
 297     pVidState->NumberRows         = 23;     /* number of rows - 1 */
 298     pVidState->BytesPerChar       = 0x10;
 299     pVidState->DCCActive          = pBiosData->DisplayCombination;
 300     pVidState->DCCAlternate       = 0;
 301     pVidState->NumberColors       = 16;
 302     pVidState->NumberPages        = 1;
 303     pVidState->NumberScanlines    = 3; /* (0,1,2,3) = (200,350,400,480) */
 304     pVidState->CharBlockPrimary   = 0;
 305     pVidState->CharBlockSecondary = 0;
 306     pVidState->MiscFlags =
 307                            (pBiosData->VGASettings & 0x0f)
 308                          | ((pBiosData->ModeOptions & 1) << 4); /* cursor emulation */
 309     pVidState->NonVGASupport      = 0;
 310     pVidState->VideoMem           = (pBiosData->ModeOptions & 0x60 >> 5);
 311     pVidState->SavePointerState   = 0;
 312     pVidState->DisplayStatus      = 4;
 313
 314     /* BIOS date string */
 315     strcpy((char *)pBiosSys+0xfff5, "13/01/99");
 316
 317     /* BIOS ID */
 318     *(pBiosSys+0xfffe) = 0xfc;
 319 }
 320
 321 /***********************************************************************
 322  *           DOSMEM_InitCollateTable
 323  *
 324  * Initialises the collate table (character sorting, language dependent)
 325  */
 326 static void DOSMEM_InitCollateTable()
 327 {
 328         DWORD           x;
 329         unsigned char   *tbl;
 330         int             i;
 331
 332         x = GlobalDOSAlloc16(258);
 333         DOSMEM_CollateTable = MAKELONG(0,(x>>16));
 334         tbl = DOSMEM_MapRealToLinear(DOSMEM_CollateTable);
 335         *(WORD*)tbl     = 0x100;
 336         tbl += 2;
 337         for ( i = 0; i < 0x100; i++) *tbl++ = i;
 338 }
 339
 340 /***********************************************************************
 341  *           DOSMEM_InitErrorTable
 342  *
 343  * Initialises the error tables (DOS 5+)
 344  */
 345 static void DOSMEM_InitErrorTable()
 346 {
 347 #if 0  /* no longer used */
 348         DWORD           x;
 349         char            *call;
 350
 351         /* We will use a snippet of real mode code that calls */
 352         /* a WINE-only interrupt to handle moving the requested */
 353         /* message into the buffer... */
 354
 355         /* FIXME - There is still something wrong... */
 356
 357         /* FIXME - Find hex values for opcodes...
 358
 359            (On call, AX contains message number
 360                      DI contains 'offset' (??)
 361             Resturn, ES:DI points to counted string )
 362
 363            PUSH BX
 364            MOV BX, AX
 365            MOV AX, (arbitrary subfunction number)
 366            INT (WINE-only interrupt)
 367            POP BX
 368            RET
 369
 370         */
 371
 372         const int       code = 4;
 373         const int       buffer = 80;
 374         const int       SIZE_TO_ALLOCATE = code + buffer;
 375
 376         /* FIXME - Complete rewrite of the table system to save */
 377         /* precious DOS space. Now, we return the 0001:???? as */
 378         /* DOS 4+ (??, it seems to be the case in MS 7.10) treats that */
 379         /* as a special case and programs will use the alternate */
 380         /* interface (a farcall returned with INT 24 (AX = 0x122e, DL = */
 381         /* 0x08) which lets us have a smaller memory footprint anyway. */
 382
 383         x = GlobalDOSAlloc16(SIZE_TO_ALLOCATE);
 384
 385         DOSMEM_ErrorCall = MAKELONG(0,(x>>16));
 386         DOSMEM_ErrorBuffer = DOSMEM_ErrorCall + code;
 387
 388         call = DOSMEM_MapRealToLinear(DOSMEM_ErrorCall);
 389
 390         memset(call, 0, SIZE_TO_ALLOCATE);
 391 #endif
 392         /* Fixme - Copy assembly into buffer here */
 393 }
 394
 395 /***********************************************************************
 396  *           DOSMEM_InitMemory
 397  *
 398  * Initialises the DOS memory structures.
 399  */
 400 static void DOSMEM_InitMemory(void)
 401 {
 402    /* Low 64Kb are reserved for DOS/BIOS so the useable area starts at
 403     * 1000:0000 and ends at 9FFF:FFEF. */
 404
 405     dosmem_info*        info_block = DOSMEM_InfoBlock();
 406     dosmem_entry*       root_block = DOSMEM_RootBlock();
 407     dosmem_entry*       dm;
 408
 409     root_block->size = DOSMEM_MemoryTop() - (((char*)root_block) + sizeof(dosmem_entry));
 410
 411     info_block->blocks = 0;
 412     info_block->free = root_block->size;
 413
 414     dm = NEXT_BLOCK(root_block);
 415     dm->size = DM_BLOCK_TERMINAL;
 416     root_block->size |= DM_BLOCK_FREE
 417 #ifdef __DOSMEM_DEBUG__
 418                      | DM_BLOCK_DEBUG;
 419 #endif
 420                      ;
 421 }
 422
 423 /**********************************************************************
 424  *              setup_dos_mem
 425  *
 426  * Setup the first megabyte for DOS memory access
 427  */
 428 static void setup_dos_mem( int dos_init )
 429 {
 430     int bios_offset = 0x400;
 431     int page_size = VIRTUAL_GetPageSize();
 432     void *addr = VIRTUAL_mmap( -1, (void *)page_size, 0x110000-page_size, 0,
 433                                PROT_READ | PROT_WRITE | PROT_EXEC, 0 );
 434     if (addr == (void *)page_size)  /* we got what we wanted */
 435     {
 436         /* now map from address 0 */
 437         addr = VIRTUAL_mmap( -1, NULL, 0x110000, 0,
 438                              PROT_READ | PROT_WRITE | PROT_EXEC, MAP_FIXED );
 439         if (addr)
 440         {
 441             ERR("MAP_FIXED failed at address 0 for DOS address space\n" );
 442             ExitProcess(1);
 443         }
 444
 445         /* inform the memory manager that there is a mapping here */
 446         VirtualAlloc( addr, 0x110000, MEM_RESERVE | MEM_SYSTEM, PAGE_EXECUTE_READWRITE );
 447
 448         /* protect the first 64K to catch NULL pointers */
 449         if (!dos_init)
 450         {
 451             VirtualProtect( addr, 0x10000, PAGE_NOACCESS, NULL );
 452             /* move the BIOS data from 0x400 to 0xf0400 */
 453             bios_offset += 0xf0000;
 454         }
 455     }
 456     else
 457     {
 458         ERR("Cannot use first megabyte for DOS address space, please report\n" );
 459         if (dos_init) ExitProcess(1);
 460         /* allocate the DOS area somewhere else */
 461         addr = VirtualAlloc( NULL, 0x110000, MEM_COMMIT, PAGE_EXECUTE_READWRITE );
 462         if (!addr)
 463         {
 464             ERR( "Cannot allocate DOS memory\n" );
 465             ExitProcess(1);
 466         }
 467     }
 468     DOSMEM_dosmem = addr;
 469     DOSMEM_biosdata = (char *)addr + bios_offset;
 470 }
 471
 472
 473 /***********************************************************************
 474  *           DOSMEM_Init
 475  *
 476  * Create the dos memory segments, and store them into the KERNEL
 477  * exported values.
 478  */
 479 BOOL DOSMEM_Init(BOOL dos_init)
 480 {
 481     static int already_done;
 482
 483     if (!already_done)
 484     {
 485         setup_dos_mem( dos_init );
 486
 487         DOSMEM_BiosDataSeg = GLOBAL_CreateBlock(GMEM_FIXED,DOSMEM_biosdata,
 488                                                 0x100, 0, FALSE, FALSE, FALSE );
 489         DOSMEM_BiosSysSeg = GLOBAL_CreateBlock(GMEM_FIXED,DOSMEM_dosmem+0xf0000,
 490                                                0x10000, 0, FALSE, FALSE, FALSE );
 491         DOSMEM_FillBiosSegments();
 492         DOSMEM_InitMemory();
 493         DOSMEM_InitCollateTable();
 494         DOSMEM_InitErrorTable();
 495         DOSMEM_InitDPMI();
 496         DOSDEV_InstallDOSDevices();
 497         already_done = 1;
 498     }
 499     else if (dos_init)
 500     {
 501         if (DOSMEM_dosmem)
 502         {
 503             ERR( "Needs access to the first megabyte for DOS mode\n" );
 504             ExitProcess(1);
 505         }
 506         MESSAGE( "Warning: unprotecting the first 64KB of memory to allow real-mode calls.\n"
 507                  "         NULL pointer accesses will no longer be caught.\n" );
 508         VirtualProtect( NULL, 0x10000, PAGE_EXECUTE_READWRITE, NULL );
 509         /* copy the BIOS area down to 0x400 */
 510         memcpy( DOSMEM_dosmem + 0x400, DOSMEM_biosdata, 0x100 );
 511         DOSMEM_biosdata = DOSMEM_dosmem + 0x400;
 512         SetSelectorBase( DOSMEM_BiosDataSeg, 0x400 );
 513     }
 514     /* interrupt table is at addr 0, so only do this when setting up DOS mode */
 515     if (dos_init) DOSMEM_FillIsrTable();
 516     return TRUE;
 517 }
 518
 519
 520 /***********************************************************************
 521  *           DOSMEM_Tick
 522  *
 523  * Increment the BIOS tick counter. Called by timer signal handler.
 524  */
 525 void DOSMEM_Tick( WORD timer )
 526 {
 527     BIOSDATA *pBiosData = DOSMEM_BiosData();
 528     if (pBiosData) pBiosData->Ticks++;
 529 }
 530
 531 /***********************************************************************
 532  *           DOSMEM_GetBlock
 533  *
 534  * Carve a chunk of the DOS memory block (without selector).
 535  */
 536 LPVOID DOSMEM_GetBlock(UINT size, UINT16* pseg)
 537 {
 538    UINT          blocksize;
 539    char         *block = NULL;
 540    dosmem_info  *info_block = DOSMEM_InfoBlock();
 541    dosmem_entry *dm;
 542 #ifdef __DOSMEM_DEBUG_
 543    dosmem_entry *prev = NULL;
 544 #endif
 545
 546    if( size > info_block->free ) return NULL;
 547    dm = DOSMEM_RootBlock();
 548
 549    while (dm && dm->size != DM_BLOCK_TERMINAL)
 550    {
 551 #ifdef __DOSMEM_DEBUG__
 552        if( (dm->size & DM_BLOCK_DEBUG) != DM_BLOCK_DEBUG )
 553        {
 554             WARN("MCB overrun! [prev = 0x%08x]\n", 4 + (UINT)prev);
 555             return NULL;
 556        }
 557        prev = dm;
 558 #endif
 559        if( dm->size & DM_BLOCK_FREE )
 560        {
 561            dosmem_entry  *next = NEXT_BLOCK(dm);
 562
 563            while( next->size & DM_BLOCK_FREE ) /* collapse free blocks */
 564            {
 565                dm->size += sizeof(dosmem_entry) + (next->size & DM_BLOCK_MASK);
 566                next->size = (DM_BLOCK_FREE | DM_BLOCK_TERMINAL);
 567                next = NEXT_BLOCK(dm);
 568            }
 569
 570            blocksize = dm->size & DM_BLOCK_MASK;
 571            if( blocksize >= size )
 572            {
 573                block = ((char*)dm) + sizeof(dosmem_entry);
 574                if( blocksize - size > 0x20 )
 575                {
 576                    /* split dm so that the next one stays
 577                     * paragraph-aligned (and dm loses free bit) */
 578
 579                    dm->size = (((size + 0xf + sizeof(dosmem_entry)) & ~0xf) -
 580                                               sizeof(dosmem_entry));
 581                    next = (dosmem_entry*)(((char*)dm) +
 582                            sizeof(dosmem_entry) + dm->size);
 583                    next->size = (blocksize - (dm->size +
 584                            sizeof(dosmem_entry))) | DM_BLOCK_FREE
 585 #ifdef __DOSMEM_DEBUG__
 586                                                   | DM_BLOCK_DEBUG
 587 #endif
 588                                                   ;
 589                } else dm->size &= DM_BLOCK_MASK;
 590
 591                info_block->blocks++;
 592                info_block->free -= dm->size;
 593                if( pseg ) *pseg = (block - DOSMEM_dosmem) >> 4;
 594 #ifdef __DOSMEM_DEBUG__
 595                dm->size |= DM_BLOCK_DEBUG;
 596 #endif
 597                break;
 598            }
 599            dm = next;
 600        }
 601        else dm = NEXT_BLOCK(dm);
 602    }
 603    return (LPVOID)block;
 604 }
 605
 606 /***********************************************************************
 607  *           DOSMEM_FreeBlock
 608  */
 609 BOOL DOSMEM_FreeBlock(void* ptr)
 610 {
 611    dosmem_info  *info_block = DOSMEM_InfoBlock();
 612
 613    if( ptr >= (void*)(((char*)DOSMEM_RootBlock()) + sizeof(dosmem_entry)) &&
 614        ptr < (void*)DOSMEM_MemoryTop() && !((((char*)ptr)
 615                   - DOSMEM_dosmem) & 0xf) )
 616    {
 617        dosmem_entry  *dm = (dosmem_entry*)(((char*)ptr) - sizeof(dosmem_entry));
 618
 619        if( !(dm->size & (DM_BLOCK_FREE | DM_BLOCK_TERMINAL))
 620 #ifdef __DOSMEM_DEBUG__
 621          && ((dm->size & DM_BLOCK_DEBUG) == DM_BLOCK_DEBUG )
 622 #endif
 623          )
 624        {
 625              info_block->blocks--;
 626              info_block->free += dm->size;
 627
 628              dm->size |= DM_BLOCK_FREE;
 629              return TRUE;
 630        }
 631    }
 632    return FALSE;
 633 }
 634
 635 /***********************************************************************
 636  *           DOSMEM_ResizeBlock
 637  */
 638 LPVOID DOSMEM_ResizeBlock(void* ptr, UINT size, UINT16* pseg)
 639 {
 640    char         *block = NULL;
 641    dosmem_info  *info_block = DOSMEM_InfoBlock();
 642
 643    if( ptr >= (void*)(((char*)DOSMEM_RootBlock()) + sizeof(dosmem_entry)) &&
 644        ptr < (void*)DOSMEM_MemoryTop() && !((((char*)ptr)
 645                   - DOSMEM_dosmem) & 0xf) )
 646    {
 647        dosmem_entry  *dm = (dosmem_entry*)(((char*)ptr) - sizeof(dosmem_entry));
 648
 649        if( pseg ) *pseg = ((char*)ptr - DOSMEM_dosmem) >> 4;
 650
 651        if( !(dm->size & (DM_BLOCK_FREE | DM_BLOCK_TERMINAL))
 652          )
 653        {
 654              dosmem_entry  *next = NEXT_BLOCK(dm);
 655              UINT blocksize, orgsize = dm->size & DM_BLOCK_MASK;
 656
 657              while( next->size & DM_BLOCK_FREE ) /* collapse free blocks */
 658              {
 659                  dm->size += sizeof(dosmem_entry) + (next->size & DM_BLOCK_MASK);
 660                  next->size = (DM_BLOCK_FREE | DM_BLOCK_TERMINAL);
 661                  next = NEXT_BLOCK(dm);
 662              }
 663
 664              blocksize = dm->size & DM_BLOCK_MASK;
 665              if (blocksize >= size)
 666              {
 667                  block = ((char*)dm) + sizeof(dosmem_entry);
 668                  if( blocksize - size > 0x20 )
 669                  {
 670                      /* split dm so that the next one stays
 671                       * paragraph-aligned (and next gains free bit) */
 672
 673                      dm->size = (((size + 0xf + sizeof(dosmem_entry)) & ~0xf) -
 674                                                 sizeof(dosmem_entry));
 675                      next = (dosmem_entry*)(((char*)dm) +
 676                              sizeof(dosmem_entry) + dm->size);
 677                      next->size = (blocksize - (dm->size +
 678                              sizeof(dosmem_entry))) | DM_BLOCK_FREE
 679                                                     ;
 680                  } else dm->size &= DM_BLOCK_MASK;
 681
 682                  info_block->free += orgsize - dm->size;
 683              } else {
 684                  /* the collapse didn't help, try getting a new block */
 685                  block = DOSMEM_GetBlock(size, pseg);
 686                  if (block) {
 687                      /* we got one, copy the old data there (we do need to, right?) */
 688                      memcpy(block, ((char*)dm) + sizeof(dosmem_entry),
 689                                    (size<orgsize) ? size : orgsize);
 690                      /* free old block */
 691                      info_block->blocks--;
 692                      info_block->free += dm->size;
 693
 694                      dm->size |= DM_BLOCK_FREE;
 695                  } else {
 696                      /* and Bill Gates said 640K should be enough for everyone... */
 697
 698                      /* need to split original and collapsed blocks apart again,
 699                       * and free the collapsed blocks again, before exiting */
 700                      if( blocksize - orgsize > 0x20 )
 701                      {
 702                          /* split dm so that the next one stays
 703                           * paragraph-aligned (and next gains free bit) */
 704
 705                          dm->size = (((orgsize + 0xf + sizeof(dosmem_entry)) & ~0xf) -
 706                                                        sizeof(dosmem_entry));
 707                          next = (dosmem_entry*)(((char*)dm) +
 708                                  sizeof(dosmem_entry) + dm->size);
 709                          next->size = (blocksize - (dm->size +
 710                                  sizeof(dosmem_entry))) | DM_BLOCK_FREE
 711                                                         ;
 712                      } else dm->size &= DM_BLOCK_MASK;
 713                  }
 714              }
 715        }
 716    }
 717    return (LPVOID)block;
 718 }
 719
 720
 721 /***********************************************************************
 722  *           DOSMEM_Available
 723  */
 724 UINT DOSMEM_Available(void)
 725 {
 726    UINT          blocksize, available = 0;
 727    dosmem_entry *dm;
 728
 729    dm = DOSMEM_RootBlock();
 730
 731    while (dm && dm->size != DM_BLOCK_TERMINAL)
 732    {
 733 #ifdef __DOSMEM_DEBUG__
 734        if( (dm->size & DM_BLOCK_DEBUG) != DM_BLOCK_DEBUG )
 735        {
 736             WARN("MCB overrun! [prev = 0x%08x]\n", 4 + (UINT)prev);
 737             return NULL;
 738        }
 739        prev = dm;
 740 #endif
 741        if( dm->size & DM_BLOCK_FREE )
 742        {
 743            dosmem_entry  *next = NEXT_BLOCK(dm);
 744
 745            while( next->size & DM_BLOCK_FREE ) /* collapse free blocks */
 746            {
 747                dm->size += sizeof(dosmem_entry) + (next->size & DM_BLOCK_MASK);
 748                next->size = (DM_BLOCK_FREE | DM_BLOCK_TERMINAL);
 749                next = NEXT_BLOCK(dm);
 750            }
 751
 752            blocksize = dm->size & DM_BLOCK_MASK;
 753            if ( blocksize > available ) available = blocksize;
 754            dm = next;
 755        }
 756        else dm = NEXT_BLOCK(dm);
 757    }
 758    return available;
 759 }
 760
 761
 762 /***********************************************************************
 763  *           DOSMEM_MapLinearToDos
 764  *
 765  * Linear address to the DOS address space.
 766  */
 767 UINT DOSMEM_MapLinearToDos(LPVOID ptr)
 768 {
 769     if (((char*)ptr >= DOSMEM_dosmem) &&
 770         ((char*)ptr < DOSMEM_dosmem + 0x100000))
 771           return (UINT)ptr - (UINT)DOSMEM_dosmem;
 772     return (UINT)ptr;
 773 }
 774
 775
 776 /***********************************************************************
 777  *           DOSMEM_MapDosToLinear
 778  *
 779  * DOS linear address to the linear address space.
 780  */
 781 LPVOID DOSMEM_MapDosToLinear(UINT ptr)
 782 {
 783     if (ptr < 0x100000) return (LPVOID)(ptr + (UINT)DOSMEM_dosmem);
 784     return (LPVOID)ptr;
 785 }
 786
 787
 788 /***********************************************************************
 789  *           DOSMEM_MapRealToLinear
 790  *
 791  * Real mode DOS address into a linear pointer
 792  */
 793 LPVOID DOSMEM_MapRealToLinear(DWORD x)
 794 {
 795    LPVOID       lin;
 796
 797    lin=DOSMEM_dosmem+(x&0xffff)+(((x&0xffff0000)>>16)*16);
 798    TRACE_(selector)("(0x%08lx) returns 0x%p.\n", x, lin );
 799    return lin;
 800 }
 801
 802 /***********************************************************************
 803  *           DOSMEM_AllocSelector
 804  *
 805  * Allocates a protected mode selector for a realmode segment.
 806  */
 807 WORD DOSMEM_AllocSelector(WORD realsel)
 808 {
 809         HMODULE16 hModule = GetModuleHandle16("KERNEL");
 810         WORD    sel;
 811
 812         sel=GLOBAL_CreateBlock(
 813                 GMEM_FIXED,DOSMEM_dosmem+realsel*16,0x10000,
 814                 hModule,FALSE,FALSE,FALSE );
 815         TRACE_(selector)("(0x%04x) returns 0x%04x.\n", realsel,sel);
 816         return sel;
 817 }
 818