diff options
| author | Joshua Clayton <stillcompiling@gmail.com> | 2017-06-14 10:36:31 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-07-17 17:26:14 +0200 |
| commit | 3b88da4aba2549497ac8868877562f1b1913ca62 (patch) | |
| tree | 71ab6007d676f87e817333e560cfaa8a7b1df671 /include/linux/bitrev.h | |
| parent | 60acfa593731f496a9f258d2e118297ef956d98d (diff) | |
lib: add bitrev8x4()
Add a function to reverse bytes within a 32 bit word.
Operate on a u32 rather than individual bytes.
Signed-off-by: Joshua Clayton <stillcompiling@gmail.com>
Signed-off-by: Alan Tull <atull@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include/linux/bitrev.h')
| -rw-r--r-- | include/linux/bitrev.h | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/include/linux/bitrev.h b/include/linux/bitrev.h index fb790b8449c1..b97be27e5a85 100644 --- a/include/linux/bitrev.h +++ b/include/linux/bitrev.h @@ -29,6 +29,8 @@ static inline u32 __bitrev32(u32 x) #endif /* CONFIG_HAVE_ARCH_BITREVERSE */ +#define __bitrev8x4(x) (__bitrev32(swab32(x))) + #define __constant_bitrev32(x) \ ({ \ u32 __x = x; \ @@ -50,6 +52,15 @@ static inline u32 __bitrev32(u32 x) __x; \ }) +#define __constant_bitrev8x4(x) \ +({ \ + u32 __x = x; \ + __x = ((__x & (u32)0xF0F0F0F0UL) >> 4) | ((__x & (u32)0x0F0F0F0FUL) << 4); \ + __x = ((__x & (u32)0xCCCCCCCCUL) >> 2) | ((__x & (u32)0x33333333UL) << 2); \ + __x = ((__x & (u32)0xAAAAAAAAUL) >> 1) | ((__x & (u32)0x55555555UL) << 1); \ + __x; \ +}) + #define __constant_bitrev8(x) \ ({ \ u8 __x = x; \ @@ -75,6 +86,14 @@ static inline u32 __bitrev32(u32 x) __bitrev16(__x); \ }) +#define bitrev8x4(x) \ +({ \ + u32 __x = x; \ + __builtin_constant_p(__x) ? \ + __constant_bitrev8x4(__x) : \ + __bitrev8x4(__x); \ + }) + #define bitrev8(x) \ ({ \ u8 __x = x; \ |