include/linux/bitrev.h

   1 #ifndef _LINUX_BITREV_H
   2 #define _LINUX_BITREV_H
   3
   4 #include <linux/types.h>
   5
   6 #ifdef CONFIG_HAVE_ARCH_BITREVERSE
   7 #include <asm/bitrev.h>
   8
   9 #define __bitrev32 __arch_bitrev32
  10 #define __bitrev16 __arch_bitrev16
  11 #define __bitrev8 __arch_bitrev8
  12
  13 #else
  14 extern u8 const byte_rev_table[256];
  15 static inline u8 __bitrev8(u8 byte)
  16 {
  17         return byte_rev_table[byte];
  18 }
  19
  20 static inline u16 __bitrev16(u16 x)
  21 {
  22         return (__bitrev8(x & 0xff) << 8) | __bitrev8(x >> 8);
  23 }
  24
  25 static inline u32 __bitrev32(u32 x)
  26 {
  27         return (__bitrev16(x & 0xffff) << 16) | __bitrev16(x >> 16);
  28 }
  29
  30 #endif /* CONFIG_HAVE_ARCH_BITREVERSE */
  31
  32 #define __bitrev8x4(x)  (__bitrev32(swab32(x)))
  33
  34 #define __constant_bitrev32(x)  \
  35 ({                                      \
  36         u32 __x = x;                    \
  37         __x = (__x >> 16) | (__x << 16);        \
  38         __x = ((__x & (u32)0xFF00FF00UL) >> 8) | ((__x & (u32)0x00FF00FFUL) << 8);      \
  39         __x = ((__x & (u32)0xF0F0F0F0UL) >> 4) | ((__x & (u32)0x0F0F0F0FUL) << 4);      \
  40         __x = ((__x & (u32)0xCCCCCCCCUL) >> 2) | ((__x & (u32)0x33333333UL) << 2);      \
  41         __x = ((__x & (u32)0xAAAAAAAAUL) >> 1) | ((__x & (u32)0x55555555UL) << 1);      \
  42         __x;                                                            \
  43 })
  44
  45 #define __constant_bitrev16(x)  \
  46 ({                                      \
  47         u16 __x = x;                    \
  48         __x = (__x >> 8) | (__x << 8);  \
  49         __x = ((__x & (u16)0xF0F0U) >> 4) | ((__x & (u16)0x0F0FU) << 4);        \
  50         __x = ((__x & (u16)0xCCCCU) >> 2) | ((__x & (u16)0x3333U) << 2);        \
  51         __x = ((__x & (u16)0xAAAAU) >> 1) | ((__x & (u16)0x5555U) << 1);        \
  52         __x;                                                            \
  53 })
  54
  55 #define __constant_bitrev8x4(x) \
  56 ({                      \
  57         u32 __x = x;    \
  58         __x = ((__x & (u32)0xF0F0F0F0UL) >> 4) | ((__x & (u32)0x0F0F0F0FUL) << 4);      \
  59         __x = ((__x & (u32)0xCCCCCCCCUL) >> 2) | ((__x & (u32)0x33333333UL) << 2);      \
  60         __x = ((__x & (u32)0xAAAAAAAAUL) >> 1) | ((__x & (u32)0x55555555UL) << 1);      \
  61         __x;                                                            \
  62 })
  63
  64 #define __constant_bitrev8(x)   \
  65 ({                                      \
  66         u8 __x = x;                     \
  67         __x = (__x >> 4) | (__x << 4);  \
  68         __x = ((__x & (u8)0xCCU) >> 2) | ((__x & (u8)0x33U) << 2);      \
  69         __x = ((__x & (u8)0xAAU) >> 1) | ((__x & (u8)0x55U) << 1);      \
  70         __x;                                                            \
  71 })
  72
  73 #define bitrev32(x) \
  74 ({                      \
  75         u32 __x = x;    \
  76         __builtin_constant_p(__x) ?     \
  77         __constant_bitrev32(__x) :                      \
  78         __bitrev32(__x);                                \
  79 })
  80
  81 #define bitrev16(x) \
  82 ({                      \
  83         u16 __x = x;    \
  84         __builtin_constant_p(__x) ?     \
  85         __constant_bitrev16(__x) :                      \
  86         __bitrev16(__x);                                \
  87  })
  88
  89 #define bitrev8x4(x) \
  90 ({                      \
  91         u32 __x = x;    \
  92         __builtin_constant_p(__x) ?     \
  93         __constant_bitrev8x4(__x) :                     \
  94         __bitrev8x4(__x);                               \
  95  })
  96
  97 #define bitrev8(x) \
  98 ({                      \
  99         u8 __x = x;     \
 100         __builtin_constant_p(__x) ?     \
 101         __constant_bitrev8(__x) :                       \
 102         __bitrev8(__x)  ;                       \
 103  })
 104 #endif /* _LINUX_BITREV_H */