diff options
| -rw-r--r-- | sword2/memory.cpp | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/sword2/memory.cpp b/sword2/memory.cpp index c8f0087996..6d348cfd29 100644 --- a/sword2/memory.cpp +++ b/sword2/memory.cpp @@ -37,6 +37,8 @@ // could only handle up to 999 blocks of memory. That means we can encode a // pointer as a 10-bit id and a 22-bit offset into the block. Judging by early // testing, both should be plenty. +// +// The number zero is used to represent the NULL pointer. #include "common/stdafx.h" #include "sword2/sword2.h" @@ -92,6 +94,9 @@ MemoryManager::~MemoryManager() { } int32 MemoryManager::encodePtr(byte *ptr) { + if (ptr == NULL) + return 0; + int idx = findPointerInIndex(ptr); assert(idx != -1); @@ -99,15 +104,18 @@ int32 MemoryManager::encodePtr(byte *ptr) { uint32 id = _memBlockIndex[idx]->id; uint32 offset = ptr - _memBlocks[id].ptr; - assert(id <= 0x03ff); + assert(id < 0x03ff); assert(offset <= 0x003fffff); assert(offset < _memBlocks[id].size); - return (id << 22) | (ptr - _memBlocks[id].ptr); + return ((id + 1) << 22) | (ptr - _memBlocks[id].ptr); } byte *MemoryManager::decodePtr(int32 n) { - uint32 id = (n & 0xffc00000) >> 22; + if (n == 0) + return NULL; + + uint32 id = ((n & 0xffc00000) >> 22) - 1; uint32 offset = n & 0x003fffff; assert(_memBlocks[id].ptr); |