drinkingtea/nostalgia
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Fix heap allocator to move header and returned address back appropriately

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This commit is contained in:
Gary Talent 2017-10-14 20:40:25 -05:00
parent 591c738730
commit fadfeea744
1 changed files with 14 additions and 7 deletions
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21
src/nostalgia/core/gba/mem.cpp
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@ -22,6 +22,7 @@ static HeapSegment *_heapIdx = nullptr;
void initHeap() {
_heapIdx = (HeapSegment*) MEM_WRAM_END;
_heapIdx--;
// set size to half of WRAM
_heapIdx->size = (MEM_WRAM_END - MEM_WRAM_BEGIN) / 2;
_heapIdx->next = nullptr;
@ -33,11 +34,13 @@ void initHeap() {
using namespace nostalgia::core;
void *operator new(size_t sz) {
void *operator new(size_t allocSize) {
// add space for heap segment header data
sz += sizeof(HeapSegment);
const auto fullSize = allocSize + sizeof(HeapSegment);
auto seg = _heapIdx;
while (seg && seg->size < sz) {
HeapSegment *prev = nullptr;
while (seg && seg->size < fullSize) {
prev = seg;
seg = seg->next;
}
@ -46,19 +49,23 @@ void *operator new(size_t sz) {
panic("Heap allocation failed");
}
seg = (HeapSegment*) (((uint8_t*) seg) - allocSize);
if (prev) {
prev->next = seg;
}
// update size for the heap segment now that it is to be considered
// allocated
seg->size = sz;
seg->next = (HeapSegment*) (((uint8_t*) seg) + sz);
seg->size = fullSize;
seg->next = (HeapSegment*) (((uint8_t*) seg) + fullSize);
seg->inUse = true;
auto out = seg + 1;
auto hs = *_heapIdx;
hs.size -= sz;
hs.size -= fullSize;
if (hs.size == 0) {
_heapIdx = hs.next;
} else {
_heapIdx = (HeapSegment*) (((uint8_t*) _heapIdx) - sz);
_heapIdx = (HeapSegment*) (((uint8_t*) _heapIdx) - fullSize);
*_heapIdx = hs;
}