Author: aandrejevic Date: Mon Jun 24 23:10:31 2013 New Revision: 59336
URL: http://svn.reactos.org/svn/reactos?rev=59336&view=rev Log: [NTVDM] Fix many VDM DOS memory manager bugs.
Modified: branches/ntvdm/subsystems/ntvdm/dos.c branches/ntvdm/subsystems/ntvdm/ntvdm.h
Modified: branches/ntvdm/subsystems/ntvdm/dos.c URL: http://svn.reactos.org/svn/reactos/branches/ntvdm/subsystems/ntvdm/dos.c?rev... ============================================================================== --- branches/ntvdm/subsystems/ntvdm/dos.c [iso-8859-1] (original) +++ branches/ntvdm/subsystems/ntvdm/dos.c [iso-8859-1] Mon Jun 24 23:10:31 2013 @@ -10,38 +10,31 @@
WORD CurrentPsp = SYSTEM_PSP, LastError = 0;
-static VOID DosCombineFreeBlocks() -{ - WORD Segment = FIRST_MCB_SEGMENT; - PDOS_MCB CurrentMcb, NextMcb; - - /* Loop through all the blocks */ +static VOID DosCombineFreeBlocks(WORD StartBlock) +{ + PDOS_MCB CurrentMcb = SEGMENT_TO_MCB(StartBlock), NextMcb; + + /* If this is the last block or it's not free, quit */ + if (CurrentMcb->BlockType == 'Z' || CurrentMcb->OwnerPsp != 0) return; + while (TRUE) { - /* Get a pointer to the MCB */ - CurrentMcb = SEGMENT_TO_MCB(Segment); - - /* Ignore the last block */ - if (CurrentMcb->BlockType == 'Z') break; - /* Get a pointer to the next MCB */ - NextMcb = SEGMENT_TO_MCB(Segment + CurrentMcb->Size + 1); - - /* If both this block and the next one are free, combine them */ - if ((CurrentMcb->OwnerPsp == 0) && (NextMcb->OwnerPsp == 0)) - { + NextMcb = SEGMENT_TO_MCB(StartBlock + CurrentMcb->Size + 1); + + /* Check if the next MCB is free */ + if (NextMcb->OwnerPsp == 0) + { + /* Combine them */ CurrentMcb->Size += NextMcb->Size + 1; CurrentMcb->BlockType = NextMcb->BlockType; - - /* Invalidate the next MCB */ NextMcb->BlockType = 'I'; - - /* Try to combine the current block again with the next one */ - continue; - } - - /* Update the segment and continue */ - Segment += CurrentMcb->Size + 1; + } + else + { + /* No more adjoining free blocks */ + break; + } } }
@@ -62,7 +55,7 @@ TotalSize++;
/* Allocate the memory for the environment block */ - DestSegment = DosAllocateMemory((TotalSize + 0x0F) >> 4); + DestSegment = DosAllocateMemory((TotalSize + 0x0F) >> 4, NULL); if (!DestSegment) return 0;
Ptr = SourceBuffer; @@ -84,12 +77,11 @@ return DestSegment; }
-WORD DosAllocateMemory(WORD Size) -{ - WORD Result = 0, Segment = FIRST_MCB_SEGMENT; +WORD DosAllocateMemory(WORD Size, WORD *MaxAvailable) +{ + WORD Result = 0, Segment = FIRST_MCB_SEGMENT, MaxSize = 0; PDOS_MCB CurrentMcb, NextMcb;
- /* Find an unallocated block */ while (TRUE) { /* Get a pointer to the MCB */ @@ -104,7 +96,13 @@ /* Only check free blocks */ if (CurrentMcb->OwnerPsp != 0) goto Next;
- /* Check if the block is big enough */ + /* Combine this free block with adjoining free blocks */ + DosCombineFreeBlocks(Segment); + + /* Update the maximum block size */ + if (CurrentMcb->Size > MaxSize) MaxSize = CurrentMcb->Size; + + /* Check if this block is big enough */ if (CurrentMcb->Size < Size) goto Next;
/* It is, update the smallest found so far */ @@ -114,15 +112,19 @@ }
Next: - /* If this was the last MCB in the chain, quit. */ + /* If this was the last MCB in the chain, quit */ if (CurrentMcb->BlockType == 'Z') break;
/* Otherwise, update the segment and continue */ Segment += CurrentMcb->Size + 1; }
- /* If we didn't find a free block, return zero */ - if (Result == 0) return 0; + /* If we didn't find a free block, return 0 */ + if (Result == 0) + { + if (MaxAvailable) *MaxAvailable = MaxSize; + return 0; + }
/* Get a pointer to the MCB */ CurrentMcb = SEGMENT_TO_MCB(Result); @@ -135,15 +137,12 @@
/* Initialize the new MCB structure */ NextMcb->BlockType = CurrentMcb->BlockType; - NextMcb->Size = Size - CurrentMcb->Size - 1; + NextMcb->Size = CurrentMcb->Size - Size - 1; NextMcb->OwnerPsp = 0;
/* Update the current block */ CurrentMcb->BlockType = 'M'; CurrentMcb->Size = Size; - - /* Combine consecutive free blocks into larger blocks */ - DosCombineFreeBlocks(); }
/* Take ownership of the block */ @@ -154,77 +153,71 @@
WORD DosResizeMemory(WORD Segment, WORD NewSize) { - WORD ReturnSize = 0, CurrentSeg; - PDOS_MCB Mcb = SEGMENT_TO_MCB(Segment), CurrentMcb; - BOOLEAN FinalBlockUsed = FALSE; - - /* We can't expand the last block */ - if (Mcb->BlockType != 'M') return 0; + WORD ReturnSize = 0, NextSegment; + PDOS_MCB Mcb = SEGMENT_TO_MCB(Segment), NextMcb; + + /* Make sure this is a valid, allocated block */ + if ((Mcb->BlockType != 'M' && Mcb->BlockType != 'Z') || Mcb->OwnerPsp == 0) + { + return 0; + }
/* Check if need to expand or contract the block */ if (NewSize > Mcb->Size) { + /* We can't expand the last block */ + if (Mcb->BlockType != 'M') return Mcb->Size; + ReturnSize = Mcb->Size; - - /* Get the segment of the next MCB */ - CurrentSeg = Segment + Mcb->Size + 1; - - /* Calculate the maximum amount of memory this block could expand to */ - while (ReturnSize < NewSize) - { - /* Get the MCB */ - CurrentMcb = SEGMENT_TO_MCB(CurrentSeg); - - /* We can't expand the block over an allocated block */ - if (CurrentMcb->OwnerPsp != 0) break; - - ReturnSize += CurrentMcb->Size + 1; - - /* Check if this is the last block */ - if (CurrentMcb->BlockType == 'Z') - { - FinalBlockUsed = TRUE; - break; - } - - /* Update the segment and continue */ - CurrentSeg += CurrentMcb->Size + 1; - } - - /* Check if we need to split the last block */ - if (ReturnSize > NewSize) - { + + /* Get the pointer and segment of the next MCB */ + NextSegment = Segment + Mcb->Size + 1; + NextMcb = SEGMENT_TO_MCB(NextSegment); + + /* Make sure the next segment is free */ + if (NextMcb->OwnerPsp != 0) return Mcb->Size; + + /* Combine this free block with adjoining free blocks */ + DosCombineFreeBlocks(NextSegment); + + /* Set the maximum possible size of the block */ + ReturnSize += NextMcb->Size + 1; + + /* Maximize the current block */ + Mcb->Size = ReturnSize; + Mcb->BlockType = NextMcb->BlockType; + + /* Invalidate the next block */ + NextMcb->BlockType = 'I'; + + /* Check if the block is larger than requested */ + if (Mcb->Size > NewSize) + { + /* It is, split it into two blocks */ + NextMcb = SEGMENT_TO_MCB(Segment + NewSize + 1); + /* Initialize the new MCB structure */ - CurrentMcb = SEGMENT_TO_MCB(Segment + NewSize + 1); - CurrentMcb->BlockType = (FinalBlockUsed) ? 'Z' : 'M'; - CurrentMcb->Size = ReturnSize - NewSize - 1; - CurrentMcb->OwnerPsp = 0; - } - - /* Calculate the new size of the block */ - ReturnSize = min(ReturnSize, NewSize); - - /* Update the MCB */ - if (FinalBlockUsed) Mcb->BlockType = 'Z'; - Mcb->Size = ReturnSize; + NextMcb->BlockType = Mcb->BlockType; + NextMcb->Size = Mcb->Size - NewSize - 1; + NextMcb->OwnerPsp = 0; + + /* Update the current block */ + Mcb->BlockType = 'M'; + Mcb->Size = NewSize; + } } else if (NewSize < Mcb->Size) { /* Just split the block */ - CurrentMcb = SEGMENT_TO_MCB(Segment + NewSize + 1); - CurrentMcb->BlockType = Mcb->BlockType; - CurrentMcb->Size = Mcb->Size - NewSize - 1; - CurrentMcb->OwnerPsp = 0; + NextMcb = SEGMENT_TO_MCB(Segment + NewSize + 1); + NextMcb->BlockType = Mcb->BlockType; + NextMcb->Size = Mcb->Size - NewSize - 1; + NextMcb->OwnerPsp = 0;
/* Update the MCB */ Mcb->BlockType = 'M'; Mcb->Size = NewSize; - - ReturnSize = NewSize; - } - - /* Combine consecutive free blocks into larger blocks */ - DosCombineFreeBlocks(); + }
return ReturnSize; } @@ -238,9 +231,6 @@
/* Mark the block as free */ Mcb->OwnerPsp = 0; - - /* Combine consecutive free blocks into larger blocks */ - DosCombineFreeBlocks();
return TRUE; } @@ -381,7 +371,7 @@ for (i = Header->e_maxalloc; i >= Header->e_minalloc; i--) { /* Try to allocate that much memory */ - Segment = DosAllocateMemory(ExeSize + (sizeof(DOS_PSP) >> 4) + i); + Segment = DosAllocateMemory(ExeSize + (sizeof(DOS_PSP) >> 4) + i, NULL); if (Segment != 0) break; }
@@ -433,7 +423,7 @@ /* COM file */
/* Allocate memory for the whole program and the PSP */ - Segment = DosAllocateMemory((FileSize + sizeof(DOS_PSP)) >> 4); + Segment = DosAllocateMemory((FileSize + sizeof(DOS_PSP)) >> 4, NULL); if (Segment == 0) goto Cleanup;
/* Copy the program to Segment:0100 */ @@ -765,10 +755,13 @@ /* Allocate Memory */ case 0x48: { - WORD Segment = DosAllocateMemory(LOWORD(Ebx)); + WORD MaxAvailable = 0; + WORD Segment = DosAllocateMemory(LOWORD(Ebx), &MaxAvailable); + if (Segment != 0) { EmulatorSetRegister(EMULATOR_REG_AX, Segment); + EmulatorSetRegister(EMULATOR_REG_BX, MaxAvailable); EmulatorClearFlag(EMULATOR_FLAG_CF); } else EmulatorSetFlag(EMULATOR_FLAG_CF);
Modified: branches/ntvdm/subsystems/ntvdm/ntvdm.h URL: http://svn.reactos.org/svn/reactos/branches/ntvdm/subsystems/ntvdm/ntvdm.h?r... ============================================================================== --- branches/ntvdm/subsystems/ntvdm/ntvdm.h [iso-8859-1] (original) +++ branches/ntvdm/subsystems/ntvdm/ntvdm.h [iso-8859-1] Mon Jun 24 23:10:31 2013 @@ -206,7 +206,7 @@ VOID BiosUpdateConsole(ULONG StartAddress, ULONG EndAddress); VOID BiosPrintCharacter(CHAR Character, BYTE Attribute); BOOLEAN DosInitialize(); -WORD DosAllocateMemory(WORD Size); +WORD DosAllocateMemory(WORD Size, WORD *MaxAvailable); BOOLEAN DosFreeMemory(WORD Segment); WORD DosResizeMemory(WORD Segment, WORD NewSize); BOOLEAN DosCreateProcess(LPCSTR CommandLine, WORD EnvBlock);
-
aandrejevic＠svn.reactos.org