diff mbox series

[v2,2/8] qemu/bswap: Replace bswapXX() by compiler __builtin_bswap()

Message ID 20200928131934.739451-3-philmd@redhat.com
State New
Headers show
Series qemu/bswap: Use compiler __builtin_bswap() | expand

Commit Message

Philippe Mathieu-Daudé Sept. 28, 2020, 1:19 p.m. UTC 
Use the compiler built-in function to byte swap values,
as the compiler is clever and will fold constants.

Suggested-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
 include/qemu/bswap.h | 33 +++++++--------------------------
 1 file changed, 7 insertions(+), 26 deletions(-)
diff mbox series

Patch

diff --git a/include/qemu/bswap.h b/include/qemu/bswap.h
index 8b01c38040c..41131d3d76e 100644
--- a/include/qemu/bswap.h
+++ b/include/qemu/bswap.h
@@ -27,32 +27,13 @@  static inline uint64_t bswap64(uint64_t x)
 {
     return bswap_64(x);
 }
-# else
-static inline uint16_t bswap16(uint16_t x)
-{
-    return (((x & 0x00ff) << 8) |
-            ((x & 0xff00) >> 8));
-}
-
-static inline uint32_t bswap32(uint32_t x)
-{
-    return (((x & 0x000000ffU) << 24) |
-            ((x & 0x0000ff00U) <<  8) |
-            ((x & 0x00ff0000U) >>  8) |
-            ((x & 0xff000000U) >> 24));
-}
-
-static inline uint64_t bswap64(uint64_t x)
-{
-    return (((x & 0x00000000000000ffULL) << 56) |
-            ((x & 0x000000000000ff00ULL) << 40) |
-            ((x & 0x0000000000ff0000ULL) << 24) |
-            ((x & 0x00000000ff000000ULL) <<  8) |
-            ((x & 0x000000ff00000000ULL) >>  8) |
-            ((x & 0x0000ff0000000000ULL) >> 24) |
-            ((x & 0x00ff000000000000ULL) >> 40) |
-            ((x & 0xff00000000000000ULL) >> 56));
-}
+#else
+#undef  bswap16
+#define bswap16(_x) __builtin_bswap16(_x)
+#undef  bswap32
+#define bswap32(_x) __builtin_bswap32(_x)
+#undef  bswap64
+#define bswap64(_x) __builtin_bswap64(_x)
 #endif /* ! CONFIG_MACHINE_BSWAP_H */
 
 static inline void bswap16s(uint16_t *s)