diff options
author | Ingo Molnar <mingo@elte.hu> | 2009-01-11 03:43:52 +0100 |
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committer | Ingo Molnar <mingo@elte.hu> | 2009-01-11 03:43:52 +0100 |
commit | 99cd7074891f87c49660e3b2880564324a4733ac (patch) | |
tree | 903d2665bcb445f1f265d1adf7a99f265bcefc15 /arch/arm/include/asm/swab.h | |
parent | e8a9cbf6ae620d9e5ba9cb42001c033287a284a3 (diff) | |
parent | c59765042f53a79a7a65585042ff463b69cb248c (diff) |
Merge commit 'v2.6.29-rc1' into tracing/urgent
Diffstat (limited to 'arch/arm/include/asm/swab.h')
-rw-r--r-- | arch/arm/include/asm/swab.h | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/arch/arm/include/asm/swab.h b/arch/arm/include/asm/swab.h new file mode 100644 index 00000000000..27a689be085 --- /dev/null +++ b/arch/arm/include/asm/swab.h @@ -0,0 +1,50 @@ +/* + * arch/arm/include/asm/byteorder.h + * + * ARM Endian-ness. In little endian mode, the data bus is connected such + * that byte accesses appear as: + * 0 = d0...d7, 1 = d8...d15, 2 = d16...d23, 3 = d24...d31 + * and word accesses (data or instruction) appear as: + * d0...d31 + * + * When in big endian mode, byte accesses appear as: + * 0 = d24...d31, 1 = d16...d23, 2 = d8...d15, 3 = d0...d7 + * and word accesses (data or instruction) appear as: + * d0...d31 + */ +#ifndef __ASM_ARM_SWAB_H +#define __ASM_ARM_SWAB_H + +#include <linux/compiler.h> +#include <asm/types.h> + +#if !defined(__STRICT_ANSI__) || defined(__KERNEL__) +# define __SWAB_64_THRU_32__ +#endif + +static inline __attribute_const__ __u32 __arch_swab32(__u32 x) +{ + __u32 t; + +#ifndef __thumb__ + if (!__builtin_constant_p(x)) { + /* + * The compiler needs a bit of a hint here to always do the + * right thing and not screw it up to different degrees + * depending on the gcc version. + */ + asm ("eor\t%0, %1, %1, ror #16" : "=r" (t) : "r" (x)); + } else +#endif + t = x ^ ((x << 16) | (x >> 16)); /* eor r1,r0,r0,ror #16 */ + + x = (x << 24) | (x >> 8); /* mov r0,r0,ror #8 */ + t &= ~0x00FF0000; /* bic r1,r1,#0x00FF0000 */ + x ^= (t >> 8); /* eor r0,r0,r1,lsr #8 */ + + return x; +} +#define __arch_swab32 __arch_swab32 + +#endif + |