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      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 
     46 static __inline__ __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 
     55 static __inline__ __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 
     64 static __inline__ __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 
     77 static __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 
     86 static __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 #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  */
    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  */
    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  */
    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  */
    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  */
    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  */
    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  */
    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  */
    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  */
    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  */
    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 
    282 #endif /* _LINUX_SWAB_H */
    283