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