1 #ifndef _LINUX_SWAB_H
2 #define _LINUX_SWAB_H
3 
4 #include <linux/types.h>
5 #include <linux/compiler.h>
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 
__fswab16(__u16 val)46 static inline __attribute_const__ __u16 __fswab16(__u16 val)
47 {
48 #ifdef __arch_swab16
49 	return __arch_swab16(val);
50 #else
51 	return ___constant_swab16(val);
52 #endif
53 }
54 
__fswab32(__u32 val)55 static inline __attribute_const__ __u32 __fswab32(__u32 val)
56 {
57 #ifdef __arch_swab32
58 	return __arch_swab32(val);
59 #else
60 	return ___constant_swab32(val);
61 #endif
62 }
63 
__fswab64(__u64 val)64 static inline __attribute_const__ __u64 __fswab64(__u64 val)
65 {
66 #ifdef __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 
__fswahw32(__u32 val)77 static inline __attribute_const__ __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 
__fswahb32(__u32 val)86 static inline __attribute_const__ __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 #define __swab16(x)				\
100 	(__builtin_constant_p((__u16)(x)) ?	\
101 	___constant_swab16(x) :			\
102 	__fswab16(x))
103 
104 /**
105  * __swab32 - return a byteswapped 32-bit value
106  * @x: value to byteswap
107  */
108 #define __swab32(x)				\
109 	(__builtin_constant_p((__u32)(x)) ?	\
110 	___constant_swab32(x) :			\
111 	__fswab32(x))
112 
113 /**
114  * __swab64 - return a byteswapped 64-bit value
115  * @x: value to byteswap
116  */
117 #define __swab64(x)				\
118 	(__builtin_constant_p((__u64)(x)) ?	\
119 	___constant_swab64(x) :			\
120 	__fswab64(x))
121 
122 /**
123  * __swahw32 - return a word-swapped 32-bit value
124  * @x: value to wordswap
125  *
126  * __swahw32(0x12340000) is 0x00001234
127  */
128 #define __swahw32(x)				\
129 	(__builtin_constant_p((__u32)(x)) ?	\
130 	___constant_swahw32(x) :		\
131 	__fswahw32(x))
132 
133 /**
134  * __swahb32 - return a high and low byte-swapped 32-bit value
135  * @x: value to byteswap
136  *
137  * __swahb32(0x12345678) is 0x34127856
138  */
139 #define __swahb32(x)				\
140 	(__builtin_constant_p((__u32)(x)) ?	\
141 	___constant_swahb32(x) :		\
142 	__fswahb32(x))
143 
144 /**
145  * __swab16p - return a byteswapped 16-bit value from a pointer
146  * @p: pointer to a naturally-aligned 16-bit value
147  */
__swab16p(const __u16 * p)148 static inline __u16 __swab16p(const __u16 *p)
149 {
150 #ifdef __arch_swab16p
151 	return __arch_swab16p(p);
152 #else
153 	return __swab16(*p);
154 #endif
155 }
156 
157 /**
158  * __swab32p - return a byteswapped 32-bit value from a pointer
159  * @p: pointer to a naturally-aligned 32-bit value
160  */
__swab32p(const __u32 * p)161 static inline __u32 __swab32p(const __u32 *p)
162 {
163 #ifdef __arch_swab32p
164 	return __arch_swab32p(p);
165 #else
166 	return __swab32(*p);
167 #endif
168 }
169 
170 /**
171  * __swab64p - return a byteswapped 64-bit value from a pointer
172  * @p: pointer to a naturally-aligned 64-bit value
173  */
__swab64p(const __u64 * p)174 static inline __u64 __swab64p(const __u64 *p)
175 {
176 #ifdef __arch_swab64p
177 	return __arch_swab64p(p);
178 #else
179 	return __swab64(*p);
180 #endif
181 }
182 
183 /**
184  * __swahw32p - return a wordswapped 32-bit value from a pointer
185  * @p: pointer to a naturally-aligned 32-bit value
186  *
187  * See __swahw32() for details of wordswapping.
188  */
__swahw32p(const __u32 * p)189 static inline __u32 __swahw32p(const __u32 *p)
190 {
191 #ifdef __arch_swahw32p
192 	return __arch_swahw32p(p);
193 #else
194 	return __swahw32(*p);
195 #endif
196 }
197 
198 /**
199  * __swahb32p - return a high and low byteswapped 32-bit value from a pointer
200  * @p: pointer to a naturally-aligned 32-bit value
201  *
202  * See __swahb32() for details of high/low byteswapping.
203  */
__swahb32p(const __u32 * p)204 static inline __u32 __swahb32p(const __u32 *p)
205 {
206 #ifdef __arch_swahb32p
207 	return __arch_swahb32p(p);
208 #else
209 	return __swahb32(*p);
210 #endif
211 }
212 
213 /**
214  * __swab16s - byteswap a 16-bit value in-place
215  * @p: pointer to a naturally-aligned 16-bit value
216  */
__swab16s(__u16 * p)217 static inline void __swab16s(__u16 *p)
218 {
219 #ifdef __arch_swab16s
220 	__arch_swab16s(p);
221 #else
222 	*p = __swab16p(p);
223 #endif
224 }
225 /**
226  * __swab32s - byteswap a 32-bit value in-place
227  * @p: pointer to a naturally-aligned 32-bit value
228  */
__swab32s(__u32 * p)229 static inline void __swab32s(__u32 *p)
230 {
231 #ifdef __arch_swab32s
232 	__arch_swab32s(p);
233 #else
234 	*p = __swab32p(p);
235 #endif
236 }
237 
238 /**
239  * __swab64s - byteswap a 64-bit value in-place
240  * @p: pointer to a naturally-aligned 64-bit value
241  */
__swab64s(__u64 * p)242 static inline void __swab64s(__u64 *p)
243 {
244 #ifdef __arch_swab64s
245 	__arch_swab64s(p);
246 #else
247 	*p = __swab64p(p);
248 #endif
249 }
250 
251 /**
252  * __swahw32s - wordswap a 32-bit value in-place
253  * @p: pointer to a naturally-aligned 32-bit value
254  *
255  * See __swahw32() for details of wordswapping
256  */
__swahw32s(__u32 * p)257 static inline void __swahw32s(__u32 *p)
258 {
259 #ifdef __arch_swahw32s
260 	__arch_swahw32s(p);
261 #else
262 	*p = __swahw32p(p);
263 #endif
264 }
265 
266 /**
267  * __swahb32s - high and low byteswap a 32-bit value in-place
268  * @p: pointer to a naturally-aligned 32-bit value
269  *
270  * See __swahb32() for details of high and low byte swapping
271  */
__swahb32s(__u32 * p)272 static inline void __swahb32s(__u32 *p)
273 {
274 #ifdef __arch_swahb32s
275 	__arch_swahb32s(p);
276 #else
277 	*p = __swahb32p(p);
278 #endif
279 }
280 
281 #ifdef __KERNEL__
282 # define swab16 __swab16
283 # define swab32 __swab32
284 # define swab64 __swab64
285 # define swahw32 __swahw32
286 # define swahb32 __swahb32
287 # define swab16p __swab16p
288 # define swab32p __swab32p
289 # define swab64p __swab64p
290 # define swahw32p __swahw32p
291 # define swahb32p __swahb32p
292 # define swab16s __swab16s
293 # define swab32s __swab32s
294 # define swab64s __swab64s
295 # define swahw32s __swahw32s
296 # define swahb32s __swahb32s
297 #endif /* __KERNEL__ */
298 
299 #endif /* _LINUX_SWAB_H */
300