1#ifndef _LINUX_SWAB_H
2#define _LINUX_SWAB_H
3
4#include <linux/types.h>
5
6#include <asm/swab.h>
7
8/*
9 * casts are necessary for constants, because we never know how for sure
10 * how U/UL/ULL map to __u16, __u32, __u64. At least not in a portable way.
11 */
12#define ___constant_swab16(x) ((__u16)( \
13 (((__u16)(x) & (__u16)0x00ffU) << 8) | \
14 (((__u16)(x) & (__u16)0xff00U) >> 8)))
15
16#define ___constant_swab32(x) ((__u32)( \
17 (((__u32)(x) & (__u32)0x000000ffUL) << 24) | \
18 (((__u32)(x) & (__u32)0x0000ff00UL) << 8) | \
19 (((__u32)(x) & (__u32)0x00ff0000UL) >> 8) | \
20 (((__u32)(x) & (__u32)0xff000000UL) >> 24)))
21
22#define ___constant_swab64(x) ((__u64)( \
23 (((__u64)(x) & (__u64)0x00000000000000ffULL) << 56) | \
24 (((__u64)(x) & (__u64)0x000000000000ff00ULL) << 40) | \
25 (((__u64)(x) & (__u64)0x0000000000ff0000ULL) << 24) | \
26 (((__u64)(x) & (__u64)0x00000000ff000000ULL) << 8) | \
27 (((__u64)(x) & (__u64)0x000000ff00000000ULL) >> 8) | \
28 (((__u64)(x) & (__u64)0x0000ff0000000000ULL) >> 24) | \
29 (((__u64)(x) & (__u64)0x00ff000000000000ULL) >> 40) | \
30 (((__u64)(x) & (__u64)0xff00000000000000ULL) >> 56)))
31
32#define ___constant_swahw32(x) ((__u32)( \
33 (((__u32)(x) & (__u32)0x0000ffffUL) << 16) | \
34 (((__u32)(x) & (__u32)0xffff0000UL) >> 16)))
35
36#define ___constant_swahb32(x) ((__u32)( \
37 (((__u32)(x) & (__u32)0x00ff00ffUL) << 8) | \
38 (((__u32)(x) & (__u32)0xff00ff00UL) >> 8)))
39
40/*
41 * Implement the following as inlines, but define the interface using
42 * macros to allow constant folding when possible:
43 * ___swab16, ___swab32, ___swab64, ___swahw32, ___swahb32
44 */
45
46static __inline__ __u16 __fswab16(__u16 val)
47{
48#if defined (__arch_swab16)
49 return __arch_swab16(val);
50#else
51 return ___constant_swab16(val);
52#endif
53}
54
55static __inline__ __u32 __fswab32(__u32 val)
56{
57#if defined(__arch_swab32)
58 return __arch_swab32(val);
59#else
60 return ___constant_swab32(val);
61#endif
62}
63
64static __inline__ __u64 __fswab64(__u64 val)
65{
66#if defined (__arch_swab64)
67 return __arch_swab64(val);
68#elif defined(__SWAB_64_THRU_32__)
69 __u32 h = val >> 32;
70 __u32 l = val & ((1ULL << 32) - 1);
71 return (((__u64)__fswab32(l)) << 32) | ((__u64)(__fswab32(h)));
72#else
73 return ___constant_swab64(val);
74#endif
75}
76
77static __inline__ __u32 __fswahw32(__u32 val)
78{
79#ifdef __arch_swahw32
80 return __arch_swahw32(val);
81#else
82 return ___constant_swahw32(val);
83#endif
84}
85
86static __inline__ __u32 __fswahb32(__u32 val)
87{
88#ifdef __arch_swahb32
89 return __arch_swahb32(val);
90#else
91 return ___constant_swahb32(val);
92#endif
93}
94
95/**
96 * __swab16 - return a byteswapped 16-bit value
97 * @x: value to byteswap
98 */
99#ifdef __HAVE_BUILTIN_BSWAP16__
100#define __swab16(x) (__u16)__builtin_bswap16((__u16)(x))
101#else
102#define __swab16(x) \
103 (__builtin_constant_p((__u16)(x)) ? \
104 ___constant_swab16(x) : \
105 __fswab16(x))
106#endif
107
108/**
109 * __swab32 - return a byteswapped 32-bit value
110 * @x: value to byteswap
111 */
112#ifdef __HAVE_BUILTIN_BSWAP32__
113#define __swab32(x) (__u32)__builtin_bswap32((__u32)(x))
114#else
115#define __swab32(x) \
116 (__builtin_constant_p((__u32)(x)) ? \
117 ___constant_swab32(x) : \
118 __fswab32(x))
119#endif
120
121/**
122 * __swab64 - return a byteswapped 64-bit value
123 * @x: value to byteswap
124 */
125#ifdef __HAVE_BUILTIN_BSWAP64__
126#define __swab64(x) (__u64)__builtin_bswap64((__u64)(x))
127#else
128#define __swab64(x) \
129 (__builtin_constant_p((__u64)(x)) ? \
130 ___constant_swab64(x) : \
131 __fswab64(x))
132#endif
133
134/**
135 * __swahw32 - return a word-swapped 32-bit value
136 * @x: value to wordswap
137 *
138 * __swahw32(0x12340000) is 0x00001234
139 */
140#define __swahw32(x) \
141 (__builtin_constant_p((__u32)(x)) ? \
142 ___constant_swahw32(x) : \
143 __fswahw32(x))
144
145/**
146 * __swahb32 - return a high and low byte-swapped 32-bit value
147 * @x: value to byteswap
148 *
149 * __swahb32(0x12345678) is 0x34127856
150 */
151#define __swahb32(x) \
152 (__builtin_constant_p((__u32)(x)) ? \
153 ___constant_swahb32(x) : \
154 __fswahb32(x))
155
156/**
157 * __swab16p - return a byteswapped 16-bit value from a pointer
158 * @p: pointer to a naturally-aligned 16-bit value
159 */
160static __always_inline __u16 __swab16p(const __u16 *p)
161{
162#ifdef __arch_swab16p
163 return __arch_swab16p(p);
164#else
165 return __swab16(*p);
166#endif
167}
168
169/**
170 * __swab32p - return a byteswapped 32-bit value from a pointer
171 * @p: pointer to a naturally-aligned 32-bit value
172 */
173static __always_inline __u32 __swab32p(const __u32 *p)
174{
175#ifdef __arch_swab32p
176 return __arch_swab32p(p);
177#else
178 return __swab32(*p);
179#endif
180}
181
182/**
183 * __swab64p - return a byteswapped 64-bit value from a pointer
184 * @p: pointer to a naturally-aligned 64-bit value
185 */
186static __always_inline __u64 __swab64p(const __u64 *p)
187{
188#ifdef __arch_swab64p
189 return __arch_swab64p(p);
190#else
191 return __swab64(*p);
192#endif
193}
194
195/**
196 * __swahw32p - return a wordswapped 32-bit value from a pointer
197 * @p: pointer to a naturally-aligned 32-bit value
198 *
199 * See __swahw32() for details of wordswapping.
200 */
201static __inline__ __u32 __swahw32p(const __u32 *p)
202{
203#ifdef __arch_swahw32p
204 return __arch_swahw32p(p);
205#else
206 return __swahw32(*p);
207#endif
208}
209
210/**
211 * __swahb32p - return a high and low byteswapped 32-bit value from a pointer
212 * @p: pointer to a naturally-aligned 32-bit value
213 *
214 * See __swahb32() for details of high/low byteswapping.
215 */
216static __inline__ __u32 __swahb32p(const __u32 *p)
217{
218#ifdef __arch_swahb32p
219 return __arch_swahb32p(p);
220#else
221 return __swahb32(*p);
222#endif
223}
224
225/**
226 * __swab16s - byteswap a 16-bit value in-place
227 * @p: pointer to a naturally-aligned 16-bit value
228 */
229static __inline__ void __swab16s(__u16 *p)
230{
231#ifdef __arch_swab16s
232 __arch_swab16s(p);
233#else
234 *p = __swab16p(p);
235#endif
236}
237/**
238 * __swab32s - byteswap a 32-bit value in-place
239 * @p: pointer to a naturally-aligned 32-bit value
240 */
241static __always_inline void __swab32s(__u32 *p)
242{
243#ifdef __arch_swab32s
244 __arch_swab32s(p);
245#else
246 *p = __swab32p(p);
247#endif
248}
249
250/**
251 * __swab64s - byteswap a 64-bit value in-place
252 * @p: pointer to a naturally-aligned 64-bit value
253 */
254static __always_inline void __swab64s(__u64 *p)
255{
256#ifdef __arch_swab64s
257 __arch_swab64s(p);
258#else
259 *p = __swab64p(p);
260#endif
261}
262
263/**
264 * __swahw32s - wordswap a 32-bit value in-place
265 * @p: pointer to a naturally-aligned 32-bit value
266 *
267 * See __swahw32() for details of wordswapping
268 */
269static __inline__ void __swahw32s(__u32 *p)
270{
271#ifdef __arch_swahw32s
272 __arch_swahw32s(p);
273#else
274 *p = __swahw32p(p);
275#endif
276}
277
278/**
279 * __swahb32s - high and low byteswap a 32-bit value in-place
280 * @p: pointer to a naturally-aligned 32-bit value
281 *
282 * See __swahb32() for details of high and low byte swapping
283 */
284static __inline__ void __swahb32s(__u32 *p)
285{
286#ifdef __arch_swahb32s
287 __arch_swahb32s(p);
288#else
289 *p = __swahb32p(p);
290#endif
291}
292
293
294#endif /* _LINUX_SWAB_H */
295