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| author |   Yalin Wang <Yalin.Wang@sonymobile.com> | 2014-11-03 03:01:03 +0100 |
|---|---|---|
| committer |   Russell King <rmk+kernel@arm.linux.org.uk> | 2014-12-22 16:43:06 +0000 |
| commit | 556d2f055bf6d79ce81587dfe774d4dd10da473f (patch) | |
| tree | 3b1eaeda540d1592936691f953607a377668f90f /include/linux/bitrev.h | |
| parent | Linux 3.19-rc1 (diff) | |
| download | linux-dev-556d2f055bf6d79ce81587dfe774d4dd10da473f.tar.xz linux-dev-556d2f055bf6d79ce81587dfe774d4dd10da473f.zip | |
ARM: 8187/1: add CONFIG_HAVE_ARCH_BITREVERSE to support rbit instruction
this change add CONFIG_HAVE_ARCH_BITREVERSE config option,
so that we can use some architecture's bitrev hardware instruction
to do bitrev operation.
Introduce __constant_bitrev* macro for constant bitrev operation.
Change __bitrev16() __bitrev32() to be inline function,
don't need export symbol for these tiny functions.
Signed-off-by: Yalin Wang <yalin.wang@sonymobile.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'include/linux/bitrev.h')
| -rw-r--r-- | include/linux/bitrev.h | 77 |
1 files changed, 73 insertions, 4 deletions
diff --git a/include/linux/bitrev.h b/include/linux/bitrev.h index 7ffe03f4693d..fb790b8449c1 100644 --- a/include/linux/bitrev.h +++ b/include/linux/bitrev.h @@ -3,14 +3,83 @@ #include <linux/types.h> -extern u8 const byte_rev_table[256]; +#ifdef CONFIG_HAVE_ARCH_BITREVERSE +#include <asm/bitrev.h> + +#define __bitrev32 __arch_bitrev32 +#define __bitrev16 __arch_bitrev16 +#define __bitrev8 __arch_bitrev8 -static inline u8 bitrev8(u8 byte) +#else +extern u8 const byte_rev_table[256]; +static inline u8 __bitrev8(u8 byte) { return byte_rev_table[byte]; } -extern u16 bitrev16(u16 in); -extern u32 bitrev32(u32 in); +static inline u16 __bitrev16(u16 x) +{ + return (__bitrev8(x & 0xff) << 8) | __bitrev8(x >> 8); +} + +static inline u32 __bitrev32(u32 x) +{ + return (__bitrev16(x & 0xffff) << 16) | __bitrev16(x >> 16); +} + +#endif /* CONFIG_HAVE_ARCH_BITREVERSE */ + +#define __constant_bitrev32(x) \ +({ \ + u32 __x = x; \ + __x = (__x >> 16) | (__x << 16); \ + __x = ((__x & (u32)0xFF00FF00UL) >> 8) | ((__x & (u32)0x00FF00FFUL) << 8); \ + __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_bitrev16(x) \ +({ \ + u16 __x = x; \ + __x = (__x >> 8) | (__x << 8); \ + __x = ((__x & (u16)0xF0F0U) >> 4) | ((__x & (u16)0x0F0FU) << 4); \ + __x = ((__x & (u16)0xCCCCU) >> 2) | ((__x & (u16)0x3333U) << 2); \ + __x = ((__x & (u16)0xAAAAU) >> 1) | ((__x & (u16)0x5555U) << 1); \ + __x; \ +}) + +#define __constant_bitrev8(x) \ +({ \ + u8 __x = x; \ + __x = (__x >> 4) | (__x << 4); \ + __x = ((__x & (u8)0xCCU) >> 2) | ((__x & (u8)0x33U) << 2); \ + __x = ((__x & (u8)0xAAU) >> 1) | ((__x & (u8)0x55U) << 1); \ + __x; \ +}) + +#define bitrev32(x) \ +({ \ + u32 __x = x; \ + __builtin_constant_p(__x) ? \ + __constant_bitrev32(__x) : \ + __bitrev32(__x); \ +}) + +#define bitrev16(x) \ +({ \ + u16 __x = x; \ + __builtin_constant_p(__x) ? \ + __constant_bitrev16(__x) : \ + __bitrev16(__x); \ + }) +#define bitrev8(x) \ +({ \ + u8 __x = x; \ + __builtin_constant_p(__x) ? \ + __constant_bitrev8(__x) : \ + __bitrev8(__x) ; \ + }) #endif /* _LINUX_BITREV_H */ |