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 	((__u16)( \
23 		(((__u16)(x) & (__u16)0x00ffU) << 8) | \
24 		(((__u16)(x) & (__u16)0xff00U) >> 8) ))
25 #define ___swab32(x) \
26 	((__u32)( \
27 		(((__u32)(x) & (__u32)0x000000ffUL) << 24) | \
28 		(((__u32)(x) & (__u32)0x0000ff00UL) <<  8) | \
29 		(((__u32)(x) & (__u32)0x00ff0000UL) >>  8) | \
30 		(((__u32)(x) & (__u32)0xff000000UL) >> 24) ))
31 #define ___swab64(x) \
32 	((__u64)( \
33 		(__u64)(((__u64)(x) & (__u64)0x00000000000000ffULL) << 56) | \
34 		(__u64)(((__u64)(x) & (__u64)0x000000000000ff00ULL) << 40) | \
35 		(__u64)(((__u64)(x) & (__u64)0x0000000000ff0000ULL) << 24) | \
36 		(__u64)(((__u64)(x) & (__u64)0x00000000ff000000ULL) <<  8) | \
37 		(__u64)(((__u64)(x) & (__u64)0x000000ff00000000ULL) >>  8) | \
38 		(__u64)(((__u64)(x) & (__u64)0x0000ff0000000000ULL) >> 24) | \
39 		(__u64)(((__u64)(x) & (__u64)0x00ff000000000000ULL) >> 40) | \
40 		(__u64)(((__u64)(x) & (__u64)0xff00000000000000ULL) >> 56) ))
41 
42 /*
43  * provide defaults when no architecture-specific optimization is detected
44  */
45 #ifndef __arch__swab16
46 #  define __arch__swab16(x) ___swab16(x)
47 #endif
48 #ifndef __arch__swab32
49 #  define __arch__swab32(x) ___swab32(x)
50 #endif
51 #ifndef __arch__swab64
52 #  define __arch__swab64(x) ___swab64(x)
53 #endif
54 
55 #ifndef __arch__swab16p
56 #  define __arch__swab16p(x) __swab16(*(x))
57 #endif
58 #ifndef __arch__swab32p
59 #  define __arch__swab32p(x) __swab32(*(x))
60 #endif
61 #ifndef __arch__swab64p
62 #  define __arch__swab64p(x) __swab64(*(x))
63 #endif
64 
65 #ifndef __arch__swab16s
66 #  define __arch__swab16s(x) do { *(x) = __swab16p((x)); } while (0)
67 #endif
68 #ifndef __arch__swab32s
69 #  define __arch__swab32s(x) do { *(x) = __swab32p((x)); } while (0)
70 #endif
71 #ifndef __arch__swab64s
72 #  define __arch__swab64s(x) do { *(x) = __swab64p((x)); } while (0)
73 #endif
74 
75 
76 /*
77  * Allow constant folding
78  */
79 #if defined(__GNUC__) && (__GNUC__ >= 2) && defined(__OPTIMIZE__)
80 #  define __swab16(x) \
81 (__builtin_constant_p((__u16)(x)) ? \
82  ___swab16((x)) : \
83  __fswab16((x)))
84 #  define __swab32(x) \
85 (__builtin_constant_p((__u32)(x)) ? \
86  ___swab32((x)) : \
87  __fswab32((x)))
88 #  define __swab64(x) \
89 (__builtin_constant_p((__u64)(x)) ? \
90  ___swab64((x)) : \
91  __fswab64((x)))
92 #else
93 #  define __swab16(x) __fswab16(x)
94 #  define __swab32(x) __fswab32(x)
95 #  define __swab64(x) __fswab64(x)
96 #endif /* OPTIMIZE */
97 
98 
__fswab16(__u16 x)99 static __inline__ __attribute__((const)) __u16 __fswab16(__u16 x)
100 {
101 	return __arch__swab16(x);
102 }
__swab16p(const __u16 * x)103 static __inline__ __u16 __swab16p(const __u16 *x)
104 {
105 	return __arch__swab16p(x);
106 }
__swab16s(__u16 * addr)107 static __inline__ void __swab16s(__u16 *addr)
108 {
109 	__arch__swab16s(addr);
110 }
111 
__fswab32(__u32 x)112 static __inline__ __attribute__((const)) __u32 __fswab32(__u32 x)
113 {
114 	return __arch__swab32(x);
115 }
__swab32p(const __u32 * x)116 static __inline__ __u32 __swab32p(const __u32 *x)
117 {
118 	return __arch__swab32p(x);
119 }
__swab32s(__u32 * addr)120 static __inline__ void __swab32s(__u32 *addr)
121 {
122 	__arch__swab32s(addr);
123 }
124 
__fswab64(__u64 x)125 static __inline__ __attribute__((const)) __u64 __fswab64(__u64 x)
126 {
127 #  ifdef __SWAB_64_THRU_32__
128 	__u32 h = x >> 32;
129 	__u32 l = x & ((1ULL<<32)-1);
130 	return (((__u64)__swab32(l)) << 32) | ((__u64)(__swab32(h)));
131 #  else
132 	return __arch__swab64(x);
133 #  endif
134 }
__swab64p(const __u64 * x)135 static __inline__ __u64 __swab64p(const __u64 *x)
136 {
137 	return __arch__swab64p(x);
138 }
__swab64s(__u64 * addr)139 static __inline__ void __swab64s(__u64 *addr)
140 {
141 	__arch__swab64s(addr);
142 }
143 
144 #if defined(__KERNEL__)
145 #define swab16 __swab16
146 #define swab32 __swab32
147 #define swab64 __swab64
148 #define swab16p __swab16p
149 #define swab32p __swab32p
150 #define swab64p __swab64p
151 #define swab16s __swab16s
152 #define swab32s __swab32s
153 #define swab64s __swab64s
154 #endif
155 
156 #endif /* _LINUX_BYTEORDER_SWAB_H */
157