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| author | midipix <writeonce@midipix.org> | 2018-08-09 04:14:31 -0400 |
|---|---|---|
| committer | midipix <writeonce@midipix.org> | 2018-08-09 04:14:31 -0400 |
| commit | dc7e61e60fb6957717a978131c3dc2dca58cf44c (patch) | |
| tree | 3532cec757961d93fa6b7ed97e5a3efb87b5cb6b | |
| parent | 1f72875a9d19a171a32e759e6251bf8d87e5bcbc (diff) | |
| download | ntapi-dc7e61e60f.tar.bz2 ntapi-dc7e61e60f.tar.xz | |
__ntapi_blt_possess(): use an inlined cmpxchg loop.
| -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); |