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[NTVDM]

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Fix many VDM DOS memory manager bugs.


svn path=/branches/ntvdm/; revision=59336
This commit is contained in:
Aleksandar Andrejevic 2013-06-24 23:10:31 +00:00
parent 07928d50d4
commit 5db2a4a6dd
2 changed files with 84 additions and 91 deletions
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173
subsystems/ntvdm/dos.c
View file

@ -10,38 +10,31 @@
WORD CurrentPsp = SYSTEM_PSP, LastError = 0;
static VOID DosCombineFreeBlocks()
static VOID DosCombineFreeBlocks(WORD StartBlock)
{
WORD Segment = FIRST_MCB_SEGMENT;
PDOS_MCB CurrentMcb, NextMcb;
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;
/* Loop through all the blocks */
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);
NextMcb = SEGMENT_TO_MCB(StartBlock + CurrentMcb->Size + 1);
/* If both this block and the next one are free, combine them */
if ((CurrentMcb->OwnerPsp == 0) && (NextMcb->OwnerPsp == 0))
/* 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 @@ static WORD DosCopyEnvironmentBlock(WORD SourceSegment)
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 @@ static WORD DosCopyEnvironmentBlock(WORD SourceSegment)
return DestSegment;
}
WORD DosAllocateMemory(WORD Size)
WORD DosAllocateMemory(WORD Size, WORD *MaxAvailable)
{
WORD Result = 0, Segment = FIRST_MCB_SEGMENT;
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 @@ WORD DosAllocateMemory(WORD Size)
/* 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 @@ WORD DosAllocateMemory(WORD Size)
}
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 @@ Next:
/* 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 */
@ -154,78 +153,72 @@ Next:
WORD DosResizeMemory(WORD Segment, WORD NewSize)
{
WORD ReturnSize = 0, CurrentSeg;
PDOS_MCB Mcb = SEGMENT_TO_MCB(Segment), CurrentMcb;
BOOLEAN FinalBlockUsed = FALSE;
WORD ReturnSize = 0, NextSegment;
PDOS_MCB Mcb = SEGMENT_TO_MCB(Segment), NextMcb;
/* We can't expand the last block */
if (Mcb->BlockType != 'M') return 0;
/* 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 pointer and segment of the next MCB */
NextSegment = Segment + Mcb->Size + 1;
NextMcb = SEGMENT_TO_MCB(NextSegment);
/* Get the segment of the next MCB */
CurrentSeg = Segment + Mcb->Size + 1;
/* Make sure the next segment is free */
if (NextMcb->OwnerPsp != 0) return Mcb->Size;
/* Calculate the maximum amount of memory this block could expand to */
while (ReturnSize < NewSize)
{
/* Get the MCB */
CurrentMcb = SEGMENT_TO_MCB(CurrentSeg);
/* Combine this free block with adjoining free blocks */
DosCombineFreeBlocks(NextSegment);
/* We can't expand the block over an allocated block */
if (CurrentMcb->OwnerPsp != 0) break;
/* Set the maximum possible size of the block */
ReturnSize += NextMcb->Size + 1;
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)
{
/* 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';
/* 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 */
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;
}
@ -239,9 +232,6 @@ BOOLEAN DosFreeMemory(WORD Segment)
/* Mark the block as free */
Mcb->OwnerPsp = 0;
/* Combine consecutive free blocks into larger blocks */
DosCombineFreeBlocks();
return TRUE;
}
@ -381,7 +371,7 @@ BOOLEAN DosCreateProcess(LPCSTR CommandLine, WORD EnvBlock)
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 @@ BOOLEAN DosCreateProcess(LPCSTR CommandLine, WORD EnvBlock)
/* 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 @@ VOID DosInt21h(WORD CodeSegment)
/* 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);

2
subsystems/ntvdm/ntvdm.h
View file

@ -206,7 +206,7 @@ BOOLEAN BiosInitialize();
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);