diff options
| -rw-r--r-- | src/blitter/ntapi_blt_block.c | 15 |
1 files changed, 11 insertions, 4 deletions
diff --git a/src/blitter/ntapi_blt_block.c b/src/blitter/ntapi_blt_block.c index 12dc2f7..803e723 100644 --- a/src/blitter/ntapi_blt_block.c +++ b/src/blitter/ntapi_blt_block.c @@ -135,14 +135,21 @@ int32_t __fastcall __ntapi_blt_possess( size_t byte; uintptr_t test; uintptr_t mask; + uintptr_t cmp; + uintptr_t xchg; bit = *blkid % (8*sizeof(size_t)); byte = *blkid / (8*sizeof(size_t)); + mask = (uintptr_t)1 << bit; + + do { + cmp = blitter->bitmap[byte]; + xchg = cmp & ~mask; - mask = ((uintptr_t)1 << bit); - test = at_locked_and( - (intptr_t *)&blitter->bitmap[byte], - ~mask); + test = at_locked_cas( + (intptr_t *)&blitter->bitmap[byte], + cmp,xchg); + } while (test != cmp); if (test & mask) { at_locked_dec(&blitter->info.blocks_avail); |