1 #ifndef _LINUX_BYTEORDER_SWAB_H 2 #define _LINUX_BYTEORDER_SWAB_H 3 4 /* 5 * linux/byteorder/swab.h 6 * Byte-swapping, independently from CPU endianness 7 * swabXX[ps]?(foo) 8 * 9 * Francois-Rene Rideau <fare (at) tunes.org> 19971205 10 * separated swab functions from cpu_to_XX, 11 * to clean up support for bizarre-endian architectures. 12 * 13 * Trent Piepho <xyzzy (at) speakeasy.org> 2007114 14 * make constant-folding work, provide C versions that 15 * gcc can optimize better, explain different versions 16 * 17 * See asm-i386/byteorder.h and suches for examples of how to provide 18 * architecture-dependent optimized versions 19 * 20 */ 21 22 23 /* Functions/macros defined, there are a lot: 24 * 25 * ___swabXX 26 * Generic C versions of the swab functions. 27 * 28 * ___constant_swabXX 29 * C versions that gcc can fold into a compile-time constant when 30 * the argument is a compile-time constant. 31 * 32 * __arch__swabXX[sp]? 33 * Architecture optimized versions of all the swab functions 34 * (including the s and p versions). These can be defined in 35 * asm-arch/byteorder.h. Any which are not, are defined here. 36 * __arch__swabXXs() is defined in terms of __arch__swabXXp(), which 37 * is defined in terms of __arch__swabXX(), which is in turn defined 38 * in terms of ___swabXX(x). 39 * These must be macros. They may be unsafe for arguments with 40 * side-effects. 41 * 42 * __fswabXX 43 * Inline function versions of the __arch__ macros. These _are_ safe 44 * if the arguments have side-effects. Note there are no s and p 45 * versions of these. 46 * 47 * __swabXX[sb] 48 * There are the ones you should actually use. The __swabXX versions 49 * will be a constant given a constant argument and use the arch 50 * specific code (if any) for non-constant arguments. The s and p 51 * versions always use the arch specific code (constant folding 52 * doesn't apply). They are safe to use with arguments with 53 * side-effects. 54 * 55 * swabXX[sb] 56 * Nicknames for __swabXX[sb] to use in the kernel. 57 */ 58 59 /* casts are necessary for constants, because we never know how for sure 60 * how U/UL/ULL map to __u16, __u32, __u64. At least not in a portable way. 61 */ 62 63 static __inline__ __u16 ___swab16(__u16 x) 64 { 65 return x<<8 | x>>8; 66 } 67 static __inline__ __u32 ___swab32(__u32 x) 68 { 69 return x<<24 | x>>24 | 70 (x & (__u32)0x0000ff00UL)<<8 | 71 (x & (__u32)0x00ff0000UL)>>8; 72 } 73 static __inline__ __u64 ___swab64(__u64 x) 74 { 75 return x<<56 | x>>56 | 76 (x & (__u64)0x000000000000ff00ULL)<<40 | 77 (x & (__u64)0x0000000000ff0000ULL)<<24 | 78 (x & (__u64)0x00000000ff000000ULL)<< 8 | 79 (x & (__u64)0x000000ff00000000ULL)>> 8 | 80 (x & (__u64)0x0000ff0000000000ULL)>>24 | 81 (x & (__u64)0x00ff000000000000ULL)>>40; 82 } 83 84 #define ___constant_swab16(x) \ 85 ((__u16)( \ 86 (((__u16)(x) & (__u16)0x00ffU) << 8) | \ 87 (((__u16)(x) & (__u16)0xff00U) >> 8) )) 88 #define ___constant_swab32(x) \ 89 ((__u32)( \ 90 (((__u32)(x) & (__u32)0x000000ffUL) << 24) | \ 91 (((__u32)(x) & (__u32)0x0000ff00UL) << 8) | \ 92 (((__u32)(x) & (__u32)0x00ff0000UL) >> 8) | \ 93 (((__u32)(x) & (__u32)0xff000000UL) >> 24) )) 94 #define ___constant_swab64(x) \ 95 ((__u64)( \ 96 (__u64)(((__u64)(x) & (__u64)0x00000000000000ffULL) << 56) | \ 97 (__u64)(((__u64)(x) & (__u64)0x000000000000ff00ULL) << 40) | \ 98 (__u64)(((__u64)(x) & (__u64)0x0000000000ff0000ULL) << 24) | \ 99 (__u64)(((__u64)(x) & (__u64)0x00000000ff000000ULL) << 8) | \ 100 (__u64)(((__u64)(x) & (__u64)0x000000ff00000000ULL) >> 8) | \ 101 (__u64)(((__u64)(x) & (__u64)0x0000ff0000000000ULL) >> 24) | \ 102 (__u64)(((__u64)(x) & (__u64)0x00ff000000000000ULL) >> 40) | \ 103 (__u64)(((__u64)(x) & (__u64)0xff00000000000000ULL) >> 56) )) 104 105 /* 106 * provide defaults when no architecture-specific optimization is detected 107 */ 108 #ifndef __arch__swab16 109 # define __arch__swab16(x) ___swab16(x) 110 #endif 111 #ifndef __arch__swab32 112 # define __arch__swab32(x) ___swab32(x) 113 #endif 114 #ifndef __arch__swab64 115 # define __arch__swab64(x) ___swab64(x) 116 #endif 117 118 #ifndef __arch__swab16p 119 # define __arch__swab16p(x) __arch__swab16(*(x)) 120 #endif 121 #ifndef __arch__swab32p 122 # define __arch__swab32p(x) __arch__swab32(*(x)) 123 #endif 124 #ifndef __arch__swab64p 125 # define __arch__swab64p(x) __arch__swab64(*(x)) 126 #endif 127 128 #ifndef __arch__swab16s 129 # define __arch__swab16s(x) ((void)(*(x) = __arch__swab16p(x))) 130 #endif 131 #ifndef __arch__swab32s 132 # define __arch__swab32s(x) ((void)(*(x) = __arch__swab32p(x))) 133 #endif 134 #ifndef __arch__swab64s 135 # define __arch__swab64s(x) ((void)(*(x) = __arch__swab64p(x))) 136 #endif 137 138 139 /* 140 * Allow constant folding 141 */ 142 #if defined(__GNUC__) && defined(__OPTIMIZE__) 143 # define __swab16(x) \ 144 (__builtin_constant_p((__u16)(x)) ? \ 145 ___constant_swab16((x)) : \ 146 __fswab16((x))) 147 # define __swab32(x) \ 148 (__builtin_constant_p((__u32)(x)) ? \ 149 ___constant_swab32((x)) : \ 150 __fswab32((x))) 151 # define __swab64(x) \ 152 (__builtin_constant_p((__u64)(x)) ? \ 153 ___constant_swab64((x)) : \ 154 __fswab64((x))) 155 #else 156 # define __swab16(x) __fswab16(x) 157 # define __swab32(x) __fswab32(x) 158 # define __swab64(x) __fswab64(x) 159 #endif /* OPTIMIZE */ 160 161 162 static __inline__ __u16 __fswab16(__u16 x) 163 { 164 return __arch__swab16(x); 165 } 166 static __inline__ __u16 __swab16p(const __u16 *x) 167 { 168 return __arch__swab16p(x); 169 } 170 static __inline__ void __swab16s(__u16 *addr) 171 { 172 __arch__swab16s(addr); 173 } 174 175 static __inline__ __u32 __fswab32(__u32 x) 176 { 177 return __arch__swab32(x); 178 } 179 static __inline__ __u32 __swab32p(const __u32 *x) 180 { 181 return __arch__swab32p(x); 182 } 183 static __inline__ void __swab32s(__u32 *addr) 184 { 185 __arch__swab32s(addr); 186 } 187 188 #ifdef __BYTEORDER_HAS_U64__ 189 static __inline__ __u64 __fswab64(__u64 x) 190 { 191 # ifdef __SWAB_64_THRU_32__ 192 __u32 h = x >> 32; 193 __u32 l = x & ((1ULL<<32)-1); 194 return (((__u64)__swab32(l)) << 32) | ((__u64)(__swab32(h))); 195 # else 196 return __arch__swab64(x); 197 # endif 198 } 199 static __inline__ __u64 __swab64p(const __u64 *x) 200 { 201 return __arch__swab64p(x); 202 } 203 static __inline__ void __swab64s(__u64 *addr) 204 { 205 __arch__swab64s(addr); 206 } 207 #endif /* __BYTEORDER_HAS_U64__ */ 208 209 210 #endif /* _LINUX_BYTEORDER_SWAB_H */ 211
