1#ifndef _LINUX_BYTEORDER_SWABB_H
2#define _LINUX_BYTEORDER_SWABB_H
3
4/*
5 * linux/byteorder/swabb.h
6 * SWAp Bytes Bizarrely
7 *	swaHHXX[ps]?(foo)
8 *
9 * Support for obNUXIous pdp-endian and other bizarre architectures.
10 * Will Linux ever run on such ancient beasts? if not, this file
11 * will be but a programming pearl. Still, it's a reminder that we
12 * shouldn't be making too many assumptions when trying to be portable.
13 *
14 */
15
16/*
17 * Meaning of the names I chose (vaxlinux people feel free to correct them):
18 * swahw32	swap 16-bit half-words in a 32-bit word
19 * swahb32	swap 8-bit halves of each 16-bit half-word in a 32-bit word
20 *
21 * No 64-bit support yet. I don't know NUXI conventions for long longs.
22 * I guarantee it will be a mess when it's there, though :->
23 * It will be even worse if there are conflicting 64-bit conventions.
24 * Hopefully, no one ever used 64-bit objects on NUXI machines.
25 *
26 */
27
28#define ___swahw32(x) \
29({ \
30	__u32 __x = (x); \
31	((__u32)( \
32		(((__u32)(__x) & (__u32)0x0000ffffUL) << 16) | \
33		(((__u32)(__x) & (__u32)0xffff0000UL) >> 16) )); \
34})
35#define ___swahb32(x) \
36({ \
37	__u32 __x = (x); \
38	((__u32)( \
39		(((__u32)(__x) & (__u32)0x00ff00ffUL) << 8) | \
40		(((__u32)(__x) & (__u32)0xff00ff00UL) >> 8) )); \
41})
42
43#define ___constant_swahw32(x) \
44	((__u32)( \
45		(((__u32)(x) & (__u32)0x0000ffffUL) << 16) | \
46		(((__u32)(x) & (__u32)0xffff0000UL) >> 16) ))
47#define ___constant_swahb32(x) \
48	((__u32)( \
49		(((__u32)(x) & (__u32)0x00ff00ffUL) << 8) | \
50		(((__u32)(x) & (__u32)0xff00ff00UL) >> 8) ))
51
52/*
53 * provide defaults when no architecture-specific optimization is detected
54 */
55#ifndef __arch__swahw32
56#  define __arch__swahw32(x) ___swahw32(x)
57#endif
58#ifndef __arch__swahb32
59#  define __arch__swahb32(x) ___swahb32(x)
60#endif
61
62#ifndef __arch__swahw32p
63#  define __arch__swahw32p(x) __swahw32(*(x))
64#endif
65#ifndef __arch__swahb32p
66#  define __arch__swahb32p(x) __swahb32(*(x))
67#endif
68
69#ifndef __arch__swahw32s
70#  define __arch__swahw32s(x) do { *(x) = __swahw32p((x)); } while (0)
71#endif
72#ifndef __arch__swahb32s
73#  define __arch__swahb32s(x) do { *(x) = __swahb32p((x)); } while (0)
74#endif
75
76
77/*
78 * Allow constant folding
79 */
80#if defined(__GNUC__) && (__GNUC__ >= 2) && defined(__OPTIMIZE__)
81#  define __swahw32(x) \
82(__builtin_constant_p((__u32)(x)) ? \
83 ___swahw32((x)) : \
84 __fswahw32((x)))
85#  define __swahb32(x) \
86(__builtin_constant_p((__u32)(x)) ? \
87 ___swahb32((x)) : \
88 __fswahb32((x)))
89#else
90#  define __swahw32(x) __fswahw32(x)
91#  define __swahb32(x) __fswahb32(x)
92#endif /* OPTIMIZE */
93
94
95static __inline__ __const__ __u32 __fswahw32(__u32 x)
96{
97	return __arch__swahw32(x);
98}
99static __inline__ __u32 __swahw32p(__u32 *x)
100{
101	return __arch__swahw32p(x);
102}
103static __inline__ void __swahw32s(__u32 *addr)
104{
105	__arch__swahw32s(addr);
106}
107
108
109static __inline__ __const__ __u32 __fswahb32(__u32 x)
110{
111	return __arch__swahb32(x);
112}
113static __inline__ __u32 __swahb32p(__u32 *x)
114{
115	return __arch__swahb32p(x);
116}
117static __inline__ void __swahb32s(__u32 *addr)
118{
119	__arch__swahb32s(addr);
120}
121
122#ifdef __BYTEORDER_HAS_U64__
123/*
124 * Not supported yet
125 */
126#endif /* __BYTEORDER_HAS_U64__ */
127
128#if defined(__KERNEL__)
129#define swahw32 __swahw32
130#define swahb32 __swahb32
131#define swahw32p __swahw32p
132#define swahb32p __swahb32p
133#define swahw32s __swahw32s
134#define swahb32s __swahb32s
135#endif
136
137#endif /* _LINUX_BYTEORDER_SWABB_H */
138