File: /usr/include/linux/byteorder/swab.h
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@tunes.org> 19971205
10 * separated swab functions from cpu_to_XX,
11 * to clean up support for bizarre-endian architectures.
12 *
13 * See asm-i386/byteorder.h and suches for examples of how to provide
14 * architecture-dependent optimized versions
15 *
16 */
17
18 /* casts are necessary for constants, because we never know how for sure
19 * how U/UL/ULL map to __u16, __u32, __u64. At least not in a portable way.
20 */
21 #define ___swab16(x) \
22 ({ \
23 __u16 __x = (x); \
24 ((__u16)( \
25 (((__u16)(__x) & (__u16)0x00ffU) << 8) | \
26 (((__u16)(__x) & (__u16)0xff00U) >> 8) )); \
27 })
28
29 #define ___swab32(x) \
30 ({ \
31 __u32 __x = (x); \
32 ((__u32)( \
33 (((__u32)(__x) & (__u32)0x000000ffUL) << 24) | \
34 (((__u32)(__x) & (__u32)0x0000ff00UL) << 8) | \
35 (((__u32)(__x) & (__u32)0x00ff0000UL) >> 8) | \
36 (((__u32)(__x) & (__u32)0xff000000UL) >> 24) )); \
37 })
38
39 #define ___swab64(x) \
40 ({ \
41 __u64 __x = (x); \
42 ((__u64)( \
43 (__u64)(((__u64)(__x) & (__u64)0x00000000000000ffULL) << 56) | \
44 (__u64)(((__u64)(__x) & (__u64)0x000000000000ff00ULL) << 40) | \
45 (__u64)(((__u64)(__x) & (__u64)0x0000000000ff0000ULL) << 24) | \
46 (__u64)(((__u64)(__x) & (__u64)0x00000000ff000000ULL) << 8) | \
47 (__u64)(((__u64)(__x) & (__u64)0x000000ff00000000ULL) >> 8) | \
48 (__u64)(((__u64)(__x) & (__u64)0x0000ff0000000000ULL) >> 24) | \
49 (__u64)(((__u64)(__x) & (__u64)0x00ff000000000000ULL) >> 40) | \
50 (__u64)(((__u64)(__x) & (__u64)0xff00000000000000ULL) >> 56) )); \
51 })
52
53 #define ___constant_swab16(x) \
54 ((__u16)( \
55 (((__u16)(x) & (__u16)0x00ffU) << 8) | \
56 (((__u16)(x) & (__u16)0xff00U) >> 8) ))
57 #define ___constant_swab32(x) \
58 ((__u32)( \
59 (((__u32)(x) & (__u32)0x000000ffUL) << 24) | \
60 (((__u32)(x) & (__u32)0x0000ff00UL) << 8) | \
61 (((__u32)(x) & (__u32)0x00ff0000UL) >> 8) | \
62 (((__u32)(x) & (__u32)0xff000000UL) >> 24) ))
63 #define ___constant_swab64(x) \
64 ((__u64)( \
65 (__u64)(((__u64)(x) & (__u64)0x00000000000000ffULL) << 56) | \
66 (__u64)(((__u64)(x) & (__u64)0x000000000000ff00ULL) << 40) | \
67 (__u64)(((__u64)(x) & (__u64)0x0000000000ff0000ULL) << 24) | \
68 (__u64)(((__u64)(x) & (__u64)0x00000000ff000000ULL) << 8) | \
69 (__u64)(((__u64)(x) & (__u64)0x000000ff00000000ULL) >> 8) | \
70 (__u64)(((__u64)(x) & (__u64)0x0000ff0000000000ULL) >> 24) | \
71 (__u64)(((__u64)(x) & (__u64)0x00ff000000000000ULL) >> 40) | \
72 (__u64)(((__u64)(x) & (__u64)0xff00000000000000ULL) >> 56) ))
73
74 /*
75 * provide defaults when no architecture-specific optimization is detected
76 */
77 #ifndef __arch__swab16
78 # define __arch__swab16(x) ({ __u16 __tmp = (x) ; ___swab16(__tmp); })
79 #endif
80 #ifndef __arch__swab32
81 # define __arch__swab32(x) ({ __u32 __tmp = (x) ; ___swab32(__tmp); })
82 #endif
83 #ifndef __arch__swab64
84 # define __arch__swab64(x) ({ __u64 __tmp = (x) ; ___swab64(__tmp); })
85 #endif
86
87 #ifndef __arch__swab16p
88 # define __arch__swab16p(x) __arch__swab16(*(x))
89 #endif
90 #ifndef __arch__swab32p
91 # define __arch__swab32p(x) __arch__swab32(*(x))
92 #endif
93 #ifndef __arch__swab64p
94 # define __arch__swab64p(x) __arch__swab64(*(x))
95 #endif
96
97 #ifndef __arch__swab16s
98 # define __arch__swab16s(x) do { *(x) = __arch__swab16p((x)); } while (0)
99 #endif
100 #ifndef __arch__swab32s
101 # define __arch__swab32s(x) do { *(x) = __arch__swab32p((x)); } while (0)
102 #endif
103 #ifndef __arch__swab64s
104 # define __arch__swab64s(x) do { *(x) = __arch__swab64p((x)); } while (0)
105 #endif
106
107
108 /*
109 * Allow constant folding
110 */
111 #if defined(__GNUC__) && (__GNUC__ >= 2) && defined(__OPTIMIZE__)
112 # define __swab16(x) \
113 (__builtin_constant_p((__u16)(x)) ? \
114 ___swab16((x)) : \
115 __fswab16((x)))
116 # define __swab32(x) \
117 (__builtin_constant_p((__u32)(x)) ? \
118 ___swab32((x)) : \
119 __fswab32((x)))
120 # define __swab64(x) \
121 (__builtin_constant_p((__u64)(x)) ? \
122 ___swab64((x)) : \
123 __fswab64((x)))
124 #else
125 # define __swab16(x) __fswab16(x)
126 # define __swab32(x) __fswab32(x)
127 # define __swab64(x) __fswab64(x)
128 #endif /* OPTIMIZE */
129
130
131 extern __inline__ __const__ __u16 __fswab16(__u16 x)
132 {
133 return __arch__swab16(x);
134 }
135 extern __inline__ __u16 __swab16p(__u16 *x)
136 {
137 return __arch__swab16p(x);
138 }
139 extern __inline__ void __swab16s(__u16 *addr)
140 {
141 __arch__swab16s(addr);
142 }
143
144 extern __inline__ __const__ __u32 __fswab32(__u32 x)
145 {
146 return __arch__swab32(x);
147 }
148 extern __inline__ __u32 __swab32p(__u32 *x)
149 {
150 return __arch__swab32p(x);
151 }
152 extern __inline__ void __swab32s(__u32 *addr)
153 {
154 __arch__swab32s(addr);
155 }
156
157 #ifdef __BYTEORDER_HAS_U64__
158 extern __inline__ __const__ __u64 __fswab64(__u64 x)
159 {
160 # ifdef __SWAB_64_THRU_32__
161 __u32 h = x >> 32;
162 __u32 l = x & ((1ULL<<32)-1);
163 return (((__u64)__swab32(l)) << 32) | ((__u64)(__swab32(h)));
164 # else
165 return __arch__swab64(x);
166 # endif
167 }
168 extern __inline__ __u64 __swab64p(__u64 *x)
169 {
170 return __arch__swab64p(x);
171 }
172 extern __inline__ void __swab64s(__u64 *addr)
173 {
174 __arch__swab64s(addr);
175 }
176 #endif /* __BYTEORDER_HAS_U64__ */
177
178 #if defined(__KERNEL__)
179 #define swab16 __swab16
180 #define swab32 __swab32
181 #define swab64 __swab64
182 #define swab16p __swab16p
183 #define swab32p __swab32p
184 #define swab64p __swab64p
185 #define swab16s __swab16s
186 #define swab32s __swab32s
187 #define swab64s __swab64s
188 #endif
189
190 #endif /* _LINUX_BYTEORDER_SWAB_H */
191