Mercurial > hg > openttd
changeset 12009:5ac019d48a1b draft
(svn r16415) -Fix (r13008): some 64bit architectures require size_t to be aligned at 8-byte boundary, ensure it for MemBlock
| author | smatz <smatz@openttd.org> |
|---|---|
| date | Sun, 24 May 2009 16:28:33 +0000 |
| parents | 066420f32d18 |
| children | d0bf08a7c260 |
| files | src/spritecache.cpp |
| diffstat | 1 files changed, 14 insertions(+), 4 deletions(-) [+] |
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line diff
--- a/src/spritecache.cpp +++ b/src/spritecache.cpp @@ -306,8 +306,18 @@ scnew->warned = false; } +/** + * S_FREE_MASK is used to mask-out lower bits of MemBlock::size + * If they are non-zero, the block is free. + * S_FREE_MASK has to ensure MemBlock is correctly aligned - + * it means 8B (S_FREE_MASK == 7) on 64bit systems! + */ +static const size_t S_FREE_MASK = sizeof(size_t) - 1; -#define S_FREE_MASK 1 +/* to make sure nobody adds things to MemBlock without checking S_FREE_MASK first */ +assert_compile(sizeof(MemBlock) == sizeof(size_t)); +/* make sure it's a power of two */ +assert_compile((sizeof(size_t) & (sizeof(size_t) - 1)) == 0); static inline MemBlock *NextBlock(MemBlock *block) { @@ -439,9 +449,9 @@ { mem_req += sizeof(MemBlock); - /* Align this to an uint32 boundary. This also makes sure that the 2 least - * bits are not used, so we could use those for other things. */ - mem_req = Align(mem_req, sizeof(uint32)); + /* Align this to correct boundary. This also makes sure at least one + * bit is not used, so we can use it for other things. */ + mem_req = Align(mem_req, S_FREE_MASK + 1); for (;;) { MemBlock *s;