diff options
| author | Richard Henderson <richard.henderson@linaro.org> | 2023-05-19 20:53:16 -0700 |
|---|---|---|
| committer | Richard Henderson <richard.henderson@linaro.org> | 2023-05-23 18:54:55 -0700 |
| commit | b35b812567f090e41c4b194bb2a752f29e9aedcc (patch) | |
| tree | 4bd808b56cc05271055c995753c366f0ba1b1fd8 | |
| parent | 427fbf3721da334c1f429d2a5285caa7025139c2 (diff) | |
qemu/atomic128: Improve cmpxchg fallback for atomic16_set
Use __sync_bool_compare_and_swap_16 to control the loop,
rather than a separate comparison.
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
| -rw-r--r-- | host/include/generic/host/atomic128-ldst.h | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/host/include/generic/host/atomic128-ldst.h b/host/include/generic/host/atomic128-ldst.h index 79d208b7a4..80fff0643a 100644 --- a/host/include/generic/host/atomic128-ldst.h +++ b/host/include/generic/host/atomic128-ldst.h @@ -58,11 +58,14 @@ atomic16_read_rw(Int128 *ptr) static inline void ATTRIBUTE_ATOMIC128_OPT atomic16_set(Int128 *ptr, Int128 val) { - Int128 old = *ptr, cmp; + __int128_t *ptr_align = __builtin_assume_aligned(ptr, 16); + __int128_t old; + Int128Alias new; + + new.s = val; do { - cmp = old; - old = atomic16_cmpxchg(ptr, cmp, val); - } while (int128_ne(old, cmp)); + old = *ptr_align; + } while (!__sync_bool_compare_and_swap_16(ptr_align, old, new.i)); } #else |