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Diffstat (limited to 'include/linux/byteorder/swab.h')
| -rw-r--r-- | include/linux/byteorder/swab.h | 222 |
1 files changed, 222 insertions, 0 deletions
diff --git a/include/linux/byteorder/swab.h b/include/linux/byteorder/swab.h new file mode 100644 index 0000000..142134f --- /dev/null +++ b/include/linux/byteorder/swab.h @@ -0,0 +1,222 @@ +#ifndef _LINUX_BYTEORDER_SWAB_H +#define _LINUX_BYTEORDER_SWAB_H + +/* + * linux/byteorder/swab.h + * Byte-swapping, independently from CPU endianness + * swabXX[ps]?(foo) + * + * Francois-Rene Rideau <fare@tunes.org> 19971205 + * separated swab functions from cpu_to_XX, + * to clean up support for bizarre-endian architectures. + * + * Trent Piepho <xyzzy@speakeasy.org> 2007114 + * make constant-folding work, provide C versions that + * gcc can optimize better, explain different versions + * + * See asm-i386/byteorder.h and suches for examples of how to provide + * architecture-dependent optimized versions + * + */ + +#include <linux/compiler.h> + +/* Functions/macros defined, there are a lot: + * + * ___swabXX + * Generic C versions of the swab functions. + * + * ___constant_swabXX + * C versions that gcc can fold into a compile-time constant when + * the argument is a compile-time constant. + * + * __arch__swabXX[sp]? + * Architecture optimized versions of all the swab functions + * (including the s and p versions). These can be defined in + * asm-arch/byteorder.h. Any which are not, are defined here. + * __arch__swabXXs() is defined in terms of __arch__swabXXp(), which + * is defined in terms of __arch__swabXX(), which is in turn defined + * in terms of ___swabXX(x). + * These must be macros. They may be unsafe for arguments with + * side-effects. + * + * __fswabXX + * Inline function versions of the __arch__ macros. These _are_ safe + * if the arguments have side-effects. Note there are no s and p + * versions of these. + * + * __swabXX[sb] + * There are the ones you should actually use. The __swabXX versions + * will be a constant given a constant argument and use the arch + * specific code (if any) for non-constant arguments. The s and p + * versions always use the arch specific code (constant folding + * doesn't apply). They are safe to use with arguments with + * side-effects. + * + * swabXX[sb] + * Nicknames for __swabXX[sb] to use in the kernel. + */ + +/* casts are necessary for constants, because we never know how for sure + * how U/UL/ULL map to __u16, __u32, __u64. At least not in a portable way. + */ + +static __inline__ __attribute_const__ __u16 ___swab16(__u16 x) +{ + return x<<8 | x>>8; +} +static __inline__ __attribute_const__ __u32 ___swab32(__u32 x) +{ + return x<<24 | x>>24 | + (x & (__u32)0x0000ff00UL)<<8 | + (x & (__u32)0x00ff0000UL)>>8; +} +static __inline__ __attribute_const__ __u64 ___swab64(__u64 x) +{ + return x<<56 | x>>56 | + (x & (__u64)0x000000000000ff00ULL)<<40 | + (x & (__u64)0x0000000000ff0000ULL)<<24 | + (x & (__u64)0x00000000ff000000ULL)<< 8 | + (x & (__u64)0x000000ff00000000ULL)>> 8 | + (x & (__u64)0x0000ff0000000000ULL)>>24 | + (x & (__u64)0x00ff000000000000ULL)>>40; +} + +#define ___constant_swab16(x) \ + ((__u16)( \ + (((__u16)(x) & (__u16)0x00ffU) << 8) | \ + (((__u16)(x) & (__u16)0xff00U) >> 8) )) +#define ___constant_swab32(x) \ + ((__u32)( \ + (((__u32)(x) & (__u32)0x000000ffUL) << 24) | \ + (((__u32)(x) & (__u32)0x0000ff00UL) << 8) | \ + (((__u32)(x) & (__u32)0x00ff0000UL) >> 8) | \ + (((__u32)(x) & (__u32)0xff000000UL) >> 24) )) +#define ___constant_swab64(x) \ + ((__u64)( \ + (__u64)(((__u64)(x) & (__u64)0x00000000000000ffULL) << 56) | \ + (__u64)(((__u64)(x) & (__u64)0x000000000000ff00ULL) << 40) | \ + (__u64)(((__u64)(x) & (__u64)0x0000000000ff0000ULL) << 24) | \ + (__u64)(((__u64)(x) & (__u64)0x00000000ff000000ULL) << 8) | \ + (__u64)(((__u64)(x) & (__u64)0x000000ff00000000ULL) >> 8) | \ + (__u64)(((__u64)(x) & (__u64)0x0000ff0000000000ULL) >> 24) | \ + (__u64)(((__u64)(x) & (__u64)0x00ff000000000000ULL) >> 40) | \ + (__u64)(((__u64)(x) & (__u64)0xff00000000000000ULL) >> 56) )) + +/* + * provide defaults when no architecture-specific optimization is detected + */ +#ifndef __arch__swab16 +# define __arch__swab16(x) ___swab16(x) +#endif +#ifndef __arch__swab32 +# define __arch__swab32(x) ___swab32(x) +#endif +#ifndef __arch__swab64 +# define __arch__swab64(x) ___swab64(x) +#endif + +#ifndef __arch__swab16p +# define __arch__swab16p(x) __arch__swab16(*(x)) +#endif +#ifndef __arch__swab32p +# define __arch__swab32p(x) __arch__swab32(*(x)) +#endif +#ifndef __arch__swab64p +# define __arch__swab64p(x) __arch__swab64(*(x)) +#endif + +#ifndef __arch__swab16s +# define __arch__swab16s(x) ((void)(*(x) = __arch__swab16p(x))) +#endif +#ifndef __arch__swab32s +# define __arch__swab32s(x) ((void)(*(x) = __arch__swab32p(x))) +#endif +#ifndef __arch__swab64s +# define __arch__swab64s(x) ((void)(*(x) = __arch__swab64p(x))) +#endif + + +/* + * Allow constant folding + */ +#if defined(__GNUC__) && defined(__OPTIMIZE__) +# define __swab16(x) \ +(__builtin_constant_p((__u16)(x)) ? \ + ___constant_swab16((x)) : \ + __fswab16((x))) +# define __swab32(x) \ +(__builtin_constant_p((__u32)(x)) ? \ + ___constant_swab32((x)) : \ + __fswab32((x))) +# define __swab64(x) \ +(__builtin_constant_p((__u64)(x)) ? \ + ___constant_swab64((x)) : \ + __fswab64((x))) +#else +# define __swab16(x) __fswab16(x) +# define __swab32(x) __fswab32(x) +# define __swab64(x) __fswab64(x) +#endif /* OPTIMIZE */ + + +static __inline__ __attribute_const__ __u16 __fswab16(__u16 x) +{ + return __arch__swab16(x); +} +static __inline__ __u16 __swab16p(const __u16 *x) +{ + return __arch__swab16p(x); +} +static __inline__ void __swab16s(__u16 *addr) +{ + __arch__swab16s(addr); +} + +static __inline__ __attribute_const__ __u32 __fswab32(__u32 x) +{ + return __arch__swab32(x); +} +static __inline__ __u32 __swab32p(const __u32 *x) +{ + return __arch__swab32p(x); +} +static __inline__ void __swab32s(__u32 *addr) +{ + __arch__swab32s(addr); +} + +#ifdef __BYTEORDER_HAS_U64__ +static __inline__ __attribute_const__ __u64 __fswab64(__u64 x) +{ +# ifdef __SWAB_64_THRU_32__ + __u32 h = x >> 32; + __u32 l = x & ((1ULL<<32)-1); + return (((__u64)__swab32(l)) << 32) | ((__u64)(__swab32(h))); +# else + return __arch__swab64(x); +# endif +} +static __inline__ __u64 __swab64p(const __u64 *x) +{ + return __arch__swab64p(x); +} +static __inline__ void __swab64s(__u64 *addr) +{ + __arch__swab64s(addr); +} +#endif /* __BYTEORDER_HAS_U64__ */ + +#if defined(__KERNEL__) +#define swab16 __swab16 +#define swab32 __swab32 +#define swab64 __swab64 +#define swab16p __swab16p +#define swab32p __swab32p +#define swab64p __swab64p +#define swab16s __swab16s +#define swab32s __swab32s +#define swab64s __swab64s +#endif + +#endif /* _LINUX_BYTEORDER_SWAB_H */ |
