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ARM: 5772/1: Use REV and REV16 for byte swapping on ARMv6+

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ARMv6 introduced the REV and REV16 instructions that reverse bytes in
words and halfwords.  Use them for the arch-specific implementation of
the byte swapping helpers on ARMv6+.

Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Rabin Vincent 2009-10-25 16:55:33 +01:00 committed by Russell King
parent a8cf81ffe0
commit 40f5b07832
1 changed files with 19 additions and 0 deletions
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19
arch/arm/include/asm/swab.h
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@ -22,6 +22,24 @@
# define __SWAB_64_THRU_32__
#endif
#if defined(__KERNEL__) && __LINUX_ARM_ARCH__ >= 6
static inline __attribute_const__ __u16 __arch_swab16(__u16 x)
{
__asm__ ("rev16 %0, %1" : "=r" (x) : "r" (x));
return x;
}
#define __arch_swab16 __arch_swab16
static inline __attribute_const__ __u32 __arch_swab32(__u32 x)
{
__asm__ ("rev %0, %1" : "=r" (x) : "r" (x));
return x;
}
#define __arch_swab32 __arch_swab32
#else
static inline __attribute_const__ __u32 __arch_swab32(__u32 x)
{
__u32 t;
@ -48,3 +66,4 @@ static inline __attribute_const__ __u32 __arch_swab32(__u32 x)
#endif
#endif