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#define ___constant_swab16(x) ___swab16(x)
43#define ___constant_swab32(x) ___swab32(x)
44#define ___constant_swab64(x) ___swab64(x)
45
46/*
47 * provide defaults when no architecture-specific optimization is detected
48 */
49#ifndef __arch__swab16
50#  define __arch__swab16(x) ___swab16(x)
51#endif
52#ifndef __arch__swab32
53#  define __arch__swab32(x) ___swab32(x)
54#endif
55#ifndef __arch__swab64
56#  define __arch__swab64(x) ___swab64(x)
57#endif
58
59#ifndef __arch__swab16p
60#  define __arch__swab16p(x) __swab16(*(x))
61#endif
62#ifndef __arch__swab32p
63#  define __arch__swab32p(x) __swab32(*(x))
64#endif
65#ifndef __arch__swab64p
66#  define __arch__swab64p(x) __swab64(*(x))
67#endif
68
69#ifndef __arch__swab16s
70#  define __arch__swab16s(x) do { *(x) = __swab16p((x)); } while (0)
71#endif
72#ifndef __arch__swab32s
73#  define __arch__swab32s(x) do { *(x) = __swab32p((x)); } while (0)
74#endif
75#ifndef __arch__swab64s
76#  define __arch__swab64s(x) do { *(x) = __swab64p((x)); } while (0)
77#endif
78
79
80/*
81 * Allow constant folding
82 */
83#if defined(__GNUC__) && (__GNUC__ >= 2) && defined(__OPTIMIZE__)
84#  define __swab16(x) \
85(__builtin_constant_p((__u16)(x)) ? \
86 ___swab16((x)) : \
87 __fswab16((x)))
88#  define __swab32(x) \
89(__builtin_constant_p((__u32)(x)) ? \
90 ___swab32((x)) : \
91 __fswab32((x)))
92#  define __swab64(x) \
93(__builtin_constant_p((__u64)(x)) ? \
94 ___swab64((x)) : \
95 __fswab64((x)))
96#else
97#  define __swab16(x) __fswab16(x)
98#  define __swab32(x) __fswab32(x)
99#  define __swab64(x) __fswab64(x)
100#endif /* OPTIMIZE */
101
102
103static __inline__ __attribute__((const)) __u16 __fswab16(__u16 x)
104{
105	return __arch__swab16(x);
106}
107static __inline__ __u16 __swab16p(const __u16 *x)
108{
109	return __arch__swab16p(x);
110}
111static __inline__ void __swab16s(__u16 *addr)
112{
113	__arch__swab16s(addr);
114}
115
116static __inline__ __attribute__((const)) __u32 __fswab32(__u32 x)
117{
118	return __arch__swab32(x);
119}
120static __inline__ __u32 __swab32p(const __u32 *x)
121{
122	return __arch__swab32p(x);
123}
124static __inline__ void __swab32s(__u32 *addr)
125{
126	__arch__swab32s(addr);
127}
128
129static __inline__ __attribute__((const)) __u64 __fswab64(__u64 x)
130{
131#  ifdef __SWAB_64_THRU_32__
132	__u32 h = x >> 32;
133	__u32 l = x & ((1ULL<<32)-1);
134	return (((__u64)__swab32(l)) << 32) | ((__u64)(__swab32(h)));
135#  else
136	return __arch__swab64(x);
137#  endif
138}
139static __inline__ __u64 __swab64p(const __u64 *x)
140{
141	return __arch__swab64p(x);
142}
143static __inline__ void __swab64s(__u64 *addr)
144{
145	__arch__swab64s(addr);
146}
147
148#if defined(__KERNEL__)
149#define swab16 __swab16
150#define swab32 __swab32
151#define swab64 __swab64
152#define swab16p __swab16p
153#define swab32p __swab32p
154#define swab64p __swab64p
155#define swab16s __swab16s
156#define swab32s __swab32s
157#define swab64s __swab64s
158#endif
159
160#endif /* _LINUX_BYTEORDER_SWAB_H */
161