diff options
| author | Richard Henderson | 2020-11-06 19:59:36 +0100 |
|---|---|---|
| committer | Richard Henderson | 2021-05-16 14:10:48 +0200 |
| commit | 5140d6be5e71cd5d75697d47ba510d117773e970 (patch) | |
| tree | e72b5968a55079e19658490b9d82e1381a8f00c9 /include | |
| parent | Merge remote-tracking branch 'remotes/marcandre/tags/rtd-pull-request' into s... (diff) | |
| download | qemu-5140d6be5e71cd5d75697d47ba510d117773e970.tar.gz qemu-5140d6be5e71cd5d75697d47ba510d117773e970.tar.xz qemu-5140d6be5e71cd5d75697d47ba510d117773e970.zip | |
qemu/host-utils: Use __builtin_bitreverseN
Clang has added some builtins for these operations;
use them if available.
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/qemu/host-utils.h | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/include/qemu/host-utils.h b/include/qemu/host-utils.h index cdca2991d8..f1e52851e0 100644 --- a/include/qemu/host-utils.h +++ b/include/qemu/host-utils.h @@ -272,6 +272,9 @@ static inline int ctpop64(uint64_t val) */ static inline uint8_t revbit8(uint8_t x) { +#if __has_builtin(__builtin_bitreverse8) + return __builtin_bitreverse8(x); +#else /* Assign the correct nibble position. */ x = ((x & 0xf0) >> 4) | ((x & 0x0f) << 4); @@ -281,6 +284,7 @@ static inline uint8_t revbit8(uint8_t x) | ((x & 0x22) << 1) | ((x & 0x11) << 3); return x; +#endif } /** @@ -289,6 +293,9 @@ static inline uint8_t revbit8(uint8_t x) */ static inline uint16_t revbit16(uint16_t x) { +#if __has_builtin(__builtin_bitreverse16) + return __builtin_bitreverse16(x); +#else /* Assign the correct byte position. */ x = bswap16(x); /* Assign the correct nibble position. */ @@ -300,6 +307,7 @@ static inline uint16_t revbit16(uint16_t x) | ((x & 0x2222) << 1) | ((x & 0x1111) << 3); return x; +#endif } /** @@ -308,6 +316,9 @@ static inline uint16_t revbit16(uint16_t x) */ static inline uint32_t revbit32(uint32_t x) { +#if __has_builtin(__builtin_bitreverse32) + return __builtin_bitreverse32(x); +#else /* Assign the correct byte position. */ x = bswap32(x); /* Assign the correct nibble position. */ @@ -319,6 +330,7 @@ static inline uint32_t revbit32(uint32_t x) | ((x & 0x22222222u) << 1) | ((x & 0x11111111u) << 3); return x; +#endif } /** @@ -327,6 +339,9 @@ static inline uint32_t revbit32(uint32_t x) */ static inline uint64_t revbit64(uint64_t x) { +#if __has_builtin(__builtin_bitreverse64) + return __builtin_bitreverse64(x); +#else /* Assign the correct byte position. */ x = bswap64(x); /* Assign the correct nibble position. */ @@ -338,6 +353,7 @@ static inline uint64_t revbit64(uint64_t x) | ((x & 0x2222222222222222ull) << 1) | ((x & 0x1111111111111111ull) << 3); return x; +#endif } /* Host type specific sizes of these routines. */ |