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Fixed an annoying problem with HeapFree() which was causing occasional instability.

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This fixes Howard's problem with peek()/poke().


git-svn-id: http://picoc.googlecode.com/svn/trunk@224 21eae674-98b7-11dd-bd71-f92a316d2d60
This commit is contained in:
zik.saleeba 2009-04-10 09:35:10 +00:00
parent 888db91168
commit 15aa51e08d
1 changed files with 21 additions and 2 deletions
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23
heap.c
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@ -20,6 +20,19 @@ static void *StackTop = &HeapMemory[0]; /* the top of the stack */
static struct AllocNode *FreeListBucket[FREELIST_BUCKETS]; /* we keep a pool of freelist buckets to reduce fragmentation */ static struct AllocNode *FreeListBucket[FREELIST_BUCKETS]; /* we keep a pool of freelist buckets to reduce fragmentation */
static struct AllocNode *FreeListBig; /* free memory which doesn't fit in a bucket */ static struct AllocNode *FreeListBig; /* free memory which doesn't fit in a bucket */
#ifdef DEBUG_HEAP
void ShowBigList()
{
struct AllocNode *LPos;
printf("Heap: bottom=0x%lx 0x%lx-0x%lx, big freelist=", (long)HeapBottom, (long)&HeapMemory[0], (long)&HeapMemory[HEAP_SIZE]);
for (LPos = FreeListBig; LPos != NULL; LPos = LPos->NextFree)
printf("0x%lx:%d ", (long)LPos, LPos->Size);
printf("\n");
}
#endif
/* initialise the stack and heap storage */ /* initialise the stack and heap storage */
void HeapInit() void HeapInit()
{ {
@ -154,7 +167,7 @@ void *HeapAlloc(int Size)
if (NewMem == NULL) if (NewMem == NULL)
{ /* couldn't allocate from a freelist - try to increase the size of the heap area */ { /* couldn't allocate from a freelist - try to increase the size of the heap area */
#ifdef DEBUG_HEAP #ifdef DEBUG_HEAP
printf("allocating %d(%d) at bottom of heap", Size, AllocSize); printf("allocating %d(%d) at bottom of heap (0x%lx-0x%lx)", Size, AllocSize, (long)(HeapBottom - AllocSize), (long)HeapBottom);
#endif #endif
if (HeapBottom - AllocSize < StackTop) if (HeapBottom - AllocSize < StackTop)
return NULL; return NULL;
@ -191,7 +204,10 @@ void HeapFree(void *Mem)
#ifdef DEBUG_HEAP #ifdef DEBUG_HEAP
printf("freeing %d from bottom of heap\n", MemNode->Size); printf("freeing %d from bottom of heap\n", MemNode->Size);
#endif #endif
HeapBottom += sizeof(int) + MemNode->Size; HeapBottom += MemNode->Size;
#ifdef DEBUG_HEAP
ShowBigList();
#endif
} }
else if (Bucket < FREELIST_BUCKETS) else if (Bucket < FREELIST_BUCKETS)
{ /* we can fit it in a bucket */ { /* we can fit it in a bucket */
@ -210,6 +226,9 @@ void HeapFree(void *Mem)
assert(FreeListBig == NULL || ((unsigned long)FreeListBig >= (unsigned long)&HeapMemory[0] && (unsigned char *)FreeListBig - &HeapMemory[0] < HEAP_SIZE)); assert(FreeListBig == NULL || ((unsigned long)FreeListBig >= (unsigned long)&HeapMemory[0] && (unsigned char *)FreeListBig - &HeapMemory[0] < HEAP_SIZE));
MemNode->NextFree = FreeListBig; MemNode->NextFree = FreeListBig;
FreeListBig = MemNode; FreeListBig = MemNode;
#ifdef DEBUG_HEAP
ShowBigList();
#endif
} }
#endif #endif
} }