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heap.cpp
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heap.cpp
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/* picoc heap memory allocation. This is a complete (but small) memory
* allocator for embedded systems which have no memory allocator. Alternatively
* you can define USE_MALLOC_HEAP to use your system's own malloc() allocator */
/* stack grows up from the bottom and heap grows down from the top of heap space */
#include "interpreter.h"
#ifdef DEBUG_HEAP
void Picoc::ShowBigList()
{
Picoc *pc=this;
struct AllocNode *LPos;
printf("Heap: bottom=0x%lx 0x%lx-0x%lx, big freelist=", (long)pc->HeapBottom, (long)&(pc->HeapMemory)[0], (long)&(pc->HeapMemory)[HEAP_SIZE]);
for (LPos = pc->FreeListBig; LPos != NULL; LPos = LPos->NextFree)
printf("0x%lx:%d ", (long)LPos, LPos->Size);
printf("\n");
}
#endif
/* initialise the stack and heap storage */
void Picoc::HeapInit( int StackOrHeapSize)
{
Picoc *pc = this;
int AlignOffset = 0;
int AlignOffsetVirtual = 0;
#ifdef USE_MALLOC_STACK
pc->HeapMemory = new unsigned char[StackOrHeapSize];
pc->HeapBottom = nullptr; /* the bottom of the (downward-growing) heap */
pc->HeapStackTop = nullptr; /* the top of the stack */
pc->HeapMemoryVirtual = new unsigned char[StackOrHeapSize];
pc->HeapBottomVirtual = nullptr; /* the bottom of the (downward-growing) heap */
pc->HeapStackTopVirtual = nullptr; /* the top of the stack */
#else
# ifdef SURVEYOR_HOST
pc->HeapMemory = (unsigned char *)C_HEAPSTART; /* all memory - stack and heap */
pc->HeapBottom = (void *)C_HEAPSTART + HEAP_SIZE; /* the bottom of the (downward-growing) heap */
pc->CurrentStackFrame = (void *)C_HEAPSTART; /* the current stack frame */
pc->HeapStackTop = (void *)C_HEAPSTART; /* the top of the stack */
pc->HeapMemStart = (void *)C_HEAPSTART;
# else
pc->HeapBottom = &HeapMemory[HEAP_SIZE]; /* the bottom of the (downward-growing) heap */
pc->CurrentStackFrame = &HeapMemory[0]; /* the current stack frame */
pc->HeapStackTop = &HeapMemory[0]; /* the top of the stack */
# endif
#endif
while (((unsigned long)&pc->HeapMemory[AlignOffset] & (sizeof(ALIGN_TYPE)-1)) != 0)
AlignOffset++;
pc->CurrentStackFrame.push_back( &(pc->HeapMemory)[AlignOffset] );
pc->HeapStackTop = &(pc->HeapMemory)[AlignOffset];
pc->HeapBottom = &(pc->HeapMemory)[StackOrHeapSize-sizeof(ALIGN_TYPE)+AlignOffset];
while (((unsigned long)&pc->HeapMemoryVirtual[AlignOffsetVirtual] & (sizeof(ALIGN_TYPE) - 1)) != 0)
AlignOffsetVirtual++;
pc->CurrentStackFrameVirtual.push_back(&(pc->HeapMemoryVirtual)[AlignOffsetVirtual]);
pc->HeapStackTopVirtual = &(pc->HeapMemoryVirtual)[AlignOffsetVirtual];
pc->HeapBottomVirtual = &(pc->HeapMemoryVirtual)[StackOrHeapSize - sizeof(ALIGN_TYPE) + AlignOffsetVirtual];
}
void Picoc::HeapCleanup()
{
Picoc *pc = this;
#ifdef USE_MALLOC_STACK
delete[] pc->HeapMemoryVirtual;
delete[] pc->HeapMemory;
#endif
}
/* allocate some space on the stack, in the current stack frame
* clears memory. can return NULL if out of stack space */
void *Picoc::HeapAllocStack( int Size)
{
Picoc *pc = this;
char *NewMem = static_cast<char*>(pc->HeapStackTop);
char *NewTop = (char *)pc->HeapStackTop + MEM_ALIGN(Size);
#ifdef DEBUG_HEAP
printf("HeapAllocStack(%ld) at 0x%lx\n", (unsigned long)MEM_ALIGN(Size), (unsigned long)pc->HeapStackTop);
#endif
if (NewTop > (char *)pc->HeapBottom)
return NULL;
pc->HeapStackTop = (void *)NewTop;
memset((void *)NewMem, '\0', Size);
return NewMem;
}
/* allocate some space on the stack, in the current stack frame
* clears memory. can return NULL if out of stack space */
void *Picoc::HeapAllocStackVirtual(int Size)
{
Picoc *pc = this;
char *NewMem = static_cast<char*>(pc->HeapStackTopVirtual);
char *NewTop = (char *)pc->HeapStackTopVirtual + MEM_ALIGN(Size);
#ifdef DEBUG_HEAP
printf("HeapAllocStack(%ld) at 0x%lx\n", (unsigned long)MEM_ALIGN(Size), (unsigned long)pc->HeapStackTop);
#endif
if (NewTop > (char *)pc->HeapBottomVirtual)
return NULL;
pc->HeapStackTopVirtual = (void *)NewTop;
memset((void *)NewMem, '\0', Size);
return NewMem;
}
/* allocate some space on the stack, in the current stack frame */
void Picoc::HeapUnpopStack( int Size)
{
Picoc *pc=this;
#ifdef DEBUG_HEAP
printf("HeapUnpopStack(%ld) at 0x%lx\n", (unsigned long)MEM_ALIGN(Size), (unsigned long)pc->HeapStackTop);
#endif
pc->HeapStackTop = (void *)((char *)pc->HeapStackTop + MEM_ALIGN(Size));
}
/* free some space at the top of the stack */
bool Picoc::HeapPopStack( void *Addr, int Size)
{
Picoc *pc = this;
int ToLose = MEM_ALIGN(Size);
if (ToLose > ((char *)pc->HeapStackTop - (char *)&(pc->HeapMemory)[0]))
return false;
#ifdef DEBUG_HEAP
printf("HeapPopStack(0x%lx, %ld) back to 0x%lx\n", (unsigned long)Addr, (unsigned long)MEM_ALIGN(Size), (unsigned long)pc->HeapStackTop - ToLose);
#endif
pc->HeapStackTop = (void *)((char *)pc->HeapStackTop - ToLose);
assert(Addr == nullptr || pc->HeapStackTop == Addr);
return true;
}
/* push a new stack frame on to the stack */
void Picoc::HeapPushStackFrame()
{
Picoc *pc = this;
#ifdef DEBUG_HEAP
printf("Adding stack frame at 0x%lx\n", (unsigned long)pc->HeapStackTop);
#endif
pc->CurrentStackFrame.push_back( pc->HeapStackTop );
pc->HeapStackTop = (void *)((char *)pc->HeapStackTop + MEM_ALIGN(sizeof(ALIGN_TYPE)));
pc->CurrentStackFrameVirtual.push_back(pc->HeapStackTopVirtual);
pc->HeapStackTopVirtual = (void *)((char *)pc->HeapStackTopVirtual + MEM_ALIGN(sizeof(ALIGN_TYPE)));
}
/* pop the current stack frame, freeing all memory in the frame. can return NULL */
void Picoc::HeapPopStackFrame()
{
Picoc *pc = this;
if( !pc->CurrentStackFrame.empty())
{
pc->HeapStackTop = pc->CurrentStackFrame.back();
pc->CurrentStackFrame.pop_back();
#ifdef DEBUG_HEAP
printf("Popping stack frame back to 0x%lx\n", (unsigned long)pc->HeapStackTop);
#endif
/* return obsolete true */;
}
if (!pc->CurrentStackFrameVirtual.empty())
{
pc->HeapStackTopVirtual = pc->CurrentStackFrameVirtual.back();
pc->CurrentStackFrameVirtual.pop_back();
#ifdef DEBUG_HEAP
printf("Popping stack frame back to 0x%lx\n", (unsigned long)pc->HeapStackTop);
#endif
}
}
void *Picoc::HeapAllocVirtualMem(int Size)
{
Picoc *pc = this;
void *ret;
ret = calloc(Size, 1);
#ifdef DEBUG_ALLOCATIONS
fprintf(stderr, "HeapAllocate value %08x\n", ret);
#endif
return ret;
}
/* allocate some dynamically allocated memory. memory is cleared. can return NULL if out of memory */
void *Picoc::HeapAllocMem( int Size)
{
Picoc *pc = this;
void *ret;
#ifdef USE_MALLOC_HEAP
ret=calloc(Size, 1);
#ifdef DEBUG_ALLOCATIONS
fprintf(stderr,"HeapAllocate value %08x\n",ret);
#endif
return ret;
#else
struct AllocNode *NewMem = NULL;
struct AllocNode **FreeNode;
int AllocSize = MEM_ALIGN(Size) + MEM_ALIGN(sizeof(NewMem->Size));
int Bucket;
void *ReturnMem;
if (Size == 0)
return NULL;
assert(Size > 0);
/* make sure we have enough space for an AllocNode */
if (AllocSize < sizeof(struct AllocNode))
AllocSize = sizeof(struct AllocNode);
Bucket = AllocSize >> 2;
if (Bucket < FREELIST_BUCKETS && pc->FreeListBucket[Bucket] != NULL)
{
/* try to allocate from a freelist bucket first */
#ifdef DEBUG_HEAP
printf("allocating %d(%d) from bucket", Size, AllocSize);
#endif
NewMem = pc->FreeListBucket[Bucket];
assert((unsigned long)NewMem >= (unsigned long)&(pc->HeapMemory)[0] && (unsigned char *)NewMem - &(pc->HeapMemory)[0] < HEAP_SIZE);
pc->FreeListBucket[Bucket] = *(struct AllocNode **)NewMem;
assert(pc->FreeListBucket[Bucket] == NULL || ((unsigned long)pc->FreeListBucket[Bucket] >= (unsigned long)&(pc->HeapMemory)[0] && (unsigned char *)pc->FreeListBucket[Bucket] - &(pc->HeapMemory)[0] < HEAP_SIZE));
NewMem->Size = AllocSize;
}
else if (pc->FreeListBig != NULL)
{
/* grab the first item from the "big" freelist we can fit in */
for (FreeNode = &pc->FreeListBig; *FreeNode != NULL && (*FreeNode)->Size < AllocSize; FreeNode = &(*FreeNode)->NextFree)
{}
if (*FreeNode != NULL)
{
assert((unsigned long)*FreeNode >= (unsigned long)&(pc->HeapMemory)[0] && (unsigned char *)*FreeNode - &(pc->HeapMemory)[0] < HEAP_SIZE);
assert((*FreeNode)->Size < HEAP_SIZE && (*FreeNode)->Size > 0);
if ((*FreeNode)->Size < AllocSize + SPLIT_MEM_THRESHOLD)
{
/* close in size - reduce fragmentation by not splitting */
#ifdef DEBUG_HEAP
printf("allocating %d(%d) from freelist, no split (%d)", Size, AllocSize, (*FreeNode)->Size);
#endif
NewMem = *FreeNode;
assert((unsigned long)NewMem >= (unsigned long)&(pc->HeapMemory)[0] && (unsigned char *)NewMem - &(pc->HeapMemory)[0] < HEAP_SIZE);
*FreeNode = NewMem->NextFree;
}
else
{
/* split this big memory chunk */
#ifdef DEBUG_HEAP
printf("allocating %d(%d) from freelist, split chunk (%d)", Size, AllocSize, (*FreeNode)->Size);
#endif
NewMem = (void *)((char *)*FreeNode + (*FreeNode)->Size - AllocSize);
assert((unsigned long)NewMem >= (unsigned long)&(pc->HeapMemory)[0] && (unsigned char *)NewMem - &(pc->HeapMemory)[0] < HEAP_SIZE);
(*FreeNode)->Size -= AllocSize;
NewMem->Size = AllocSize;
}
}
}
if (NewMem == NULL)
{
/* couldn't allocate from a freelist - try to increase the size of the heap area */
#ifdef DEBUG_HEAP
printf("allocating %d(%d) at bottom of heap (0x%lx-0x%lx)", Size, AllocSize, (long)((char *)pc->HeapBottom - AllocSize), (long)HeapBottom);
#endif
if ((char *)pc->HeapBottom - AllocSize < (char *)pc->HeapStackTop)
return NULL;
pc->HeapBottom = (void *)((char *)pc->HeapBottom - AllocSize);
NewMem = pc->HeapBottom;
NewMem->Size = AllocSize;
}
ReturnMem = (void *)((char *)NewMem + MEM_ALIGN(sizeof(NewMem->Size)));
memset(ReturnMem, '\0', AllocSize - MEM_ALIGN(sizeof(NewMem->Size)));
#ifdef DEBUG_HEAP
printf(" = %lx\n", (unsigned long)ReturnMem);
#endif
return ReturnMem;
#endif
}
/* free some dynamically allocated memory */
void Picoc::HeapFreeMem( void *Mem)
{
Picoc *pc = this;
#ifdef DEBUG_ALLOCATIONS
fprintf(stderr, "HeapFree value %08x\n", Mem);
#endif
#ifdef USE_MALLOC_HEAP
free(Mem);
#else
struct AllocNode *MemNode = (struct AllocNode *)((char *)Mem - MEM_ALIGN(sizeof(MemNode->Size)));
int Bucket = MemNode->Size >> 2;
#ifdef DEBUG_HEAP
printf("HeapFreeMem(0x%lx)\n", (unsigned long)Mem);
#endif
assert((unsigned long)Mem >= (unsigned long)&(pc->HeapMemory)[0] && (unsigned char *)Mem - &(pc->HeapMemory)[0] < HEAP_SIZE);
assert(MemNode->Size < HEAP_SIZE && MemNode->Size > 0);
if (Mem == NULL)
return;
if ((void *)MemNode == pc->HeapBottom)
{
/* pop it off the bottom of the heap, reducing the heap size */
#ifdef DEBUG_HEAP
printf("freeing %d from bottom of heap\n", MemNode->Size);
#endif
pc->HeapBottom = (void *)((char *)pc->HeapBottom + MemNode->Size);
#ifdef DEBUG_HEAP
ShowBigList(pc);
#endif
}
else if (Bucket < FREELIST_BUCKETS)
{
/* we can fit it in a bucket */
#ifdef DEBUG_HEAP
printf("freeing %d to bucket\n", MemNode->Size);
#endif
assert(pc->FreeListBucket[Bucket] == NULL || ((unsigned long)pc->FreeListBucket[Bucket] >= (unsigned long)&(pc->HeapMemory)[0] && (unsigned char *)FreeListBucket[Bucket] - &HeapMemory[0] < HEAP_SIZE));
*(struct AllocNode **)MemNode = pc->FreeListBucket[Bucket];
pc->FreeListBucket[Bucket] = (struct AllocNode *)MemNode;
}
else
{
/* put it in the big memory freelist */
#ifdef DEBUG_HEAP
printf("freeing %lx:%d to freelist\n", (unsigned long)Mem, MemNode->Size);
#endif
assert(pc->FreeListBig == NULL || ((unsigned long)pc->FreeListBig >= (unsigned long)&(pc->HeapMemory)[0] && (unsigned char *)pc->FreeListBig - &(pc->HeapMemory)[0] < HEAP_SIZE));
MemNode->NextFree = pc->FreeListBig;
FreeListBig = MemNode;
#ifdef DEBUG_HEAP
ShowBigList(pc);
#endif
}
#endif
}
/* free some dynamically allocated memory */
void Picoc::HeapFreeMem(UnionAnyValuePointer Mem)
{
Picoc *pc = this;
#ifdef DEBUG_ALLOCATIONS
fprintf(stderr, "HeapFree value %08x\n", Mem);
#endif
#ifdef USE_MALLOC_HEAP
free(Mem);
#else
struct AllocNode *MemNode = (struct AllocNode *)((char *)Mem - MEM_ALIGN(sizeof(MemNode->Size)));
int Bucket = MemNode->Size >> 2;
#ifdef DEBUG_HEAP
printf("HeapFreeMem(0x%lx)\n", (unsigned long)Mem);
#endif
assert((unsigned long)Mem >= (unsigned long)&(pc->HeapMemory)[0] && (unsigned char *)Mem - &(pc->HeapMemory)[0] < HEAP_SIZE);
assert(MemNode->Size < HEAP_SIZE && MemNode->Size > 0);
if (Mem == NULL)
return;
if ((void *)MemNode == pc->HeapBottom)
{
/* pop it off the bottom of the heap, reducing the heap size */
#ifdef DEBUG_HEAP
printf("freeing %d from bottom of heap\n", MemNode->Size);
#endif
pc->HeapBottom = (void *)((char *)pc->HeapBottom + MemNode->Size);
#ifdef DEBUG_HEAP
ShowBigList(pc);
#endif
}
else if (Bucket < FREELIST_BUCKETS)
{
/* we can fit it in a bucket */
#ifdef DEBUG_HEAP
printf("freeing %d to bucket\n", MemNode->Size);
#endif
assert(pc->FreeListBucket[Bucket] == NULL || ((unsigned long)pc->FreeListBucket[Bucket] >= (unsigned long)&(pc->HeapMemory)[0] && (unsigned char *)FreeListBucket[Bucket] - &HeapMemory[0] < HEAP_SIZE));
*(struct AllocNode **)MemNode = pc->FreeListBucket[Bucket];
pc->FreeListBucket[Bucket] = (struct AllocNode *)MemNode;
}
else
{
/* put it in the big memory freelist */
#ifdef DEBUG_HEAP
printf("freeing %lx:%d to freelist\n", (unsigned long)Mem, MemNode->Size);
#endif
assert(pc->FreeListBig == NULL || ((unsigned long)pc->FreeListBig >= (unsigned long)&(pc->HeapMemory)[0] && (unsigned char *)pc->FreeListBig - &(pc->HeapMemory)[0] < HEAP_SIZE));
MemNode->NextFree = pc->FreeListBig;
FreeListBig = MemNode;
#ifdef DEBUG_HEAP
ShowBigList(pc);
#endif
}
#endif
}