include/linux/bitrev.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _LINUX_BITREV_H
   3 #define _LINUX_BITREV_H
   4
   5 #include <linux/types.h>
   6
   7 #ifdef CONFIG_HAVE_ARCH_BITREVERSE
   8 #include <asm/bitrev.h>
   9
  10 #define __bitrev32 __arch_bitrev32
  11 #define __bitrev16 __arch_bitrev16
  12 #define __bitrev8 __arch_bitrev8
  13
  14 #else
  15 extern u8 const byte_rev_table[256];
  16 static inline u8 __bitrev8(u8 byte)
  17 {
  18         return byte_rev_table[byte];
  19 }
  20
  21 static inline u16 __bitrev16(u16 x)
  22 {
  23         return (__bitrev8(x & 0xff) << 8) | __bitrev8(x >> 8);
  24 }
  25
  26 static inline u32 __bitrev32(u32 x)
  27 {
  28         return (__bitrev16(x & 0xffff) << 16) | __bitrev16(x >> 16);
  29 }
  30
  31 #endif /* CONFIG_HAVE_ARCH_BITREVERSE */
  32
  33 #define __bitrev8x4(x)  (__bitrev32(swab32(x)))
  34
  35 #define __constant_bitrev32(x)  \
  36 ({                                      \
  37         u32 ___x = x;                   \
  38         ___x = (___x >> 16) | (___x << 16);     \
  39         ___x = ((___x & (u32)0xFF00FF00UL) >> 8) | ((___x & (u32)0x00FF00FFUL) << 8);   \
  40         ___x = ((___x & (u32)0xF0F0F0F0UL) >> 4) | ((___x & (u32)0x0F0F0F0FUL) << 4);   \
  41         ___x = ((___x & (u32)0xCCCCCCCCUL) >> 2) | ((___x & (u32)0x33333333UL) << 2);   \
  42         ___x = ((___x & (u32)0xAAAAAAAAUL) >> 1) | ((___x & (u32)0x55555555UL) << 1);   \
  43         ___x;                                                           \
  44 })
  45
  46 #define __constant_bitrev16(x)  \
  47 ({                                      \
  48         u16 ___x = x;                   \
  49         ___x = (___x >> 8) | (___x << 8);       \
  50         ___x = ((___x & (u16)0xF0F0U) >> 4) | ((___x & (u16)0x0F0FU) << 4);     \
  51         ___x = ((___x & (u16)0xCCCCU) >> 2) | ((___x & (u16)0x3333U) << 2);     \
  52         ___x = ((___x & (u16)0xAAAAU) >> 1) | ((___x & (u16)0x5555U) << 1);     \
  53         ___x;                                                           \
  54 })
  55
  56 #define __constant_bitrev8x4(x) \
  57 ({                      \
  58         u32 ___x = x;   \
  59         ___x = ((___x & (u32)0xF0F0F0F0UL) >> 4) | ((___x & (u32)0x0F0F0F0FUL) << 4);   \
  60         ___x = ((___x & (u32)0xCCCCCCCCUL) >> 2) | ((___x & (u32)0x33333333UL) << 2);   \
  61         ___x = ((___x & (u32)0xAAAAAAAAUL) >> 1) | ((___x & (u32)0x55555555UL) << 1);   \
  62         ___x;                                                           \
  63 })
  64
  65 #define __constant_bitrev8(x)   \
  66 ({                                      \
  67         u8 ___x = x;                    \
  68         ___x = (___x >> 4) | (___x << 4);       \
  69         ___x = ((___x & (u8)0xCCU) >> 2) | ((___x & (u8)0x33U) << 2);   \
  70         ___x = ((___x & (u8)0xAAU) >> 1) | ((___x & (u8)0x55U) << 1);   \
  71         ___x;                                                           \
  72 })
  73
  74 #define bitrev32(x) \
  75 ({                      \
  76         u32 __x = x;    \
  77         __builtin_constant_p(__x) ?     \
  78         __constant_bitrev32(__x) :                      \
  79         __bitrev32(__x);                                \
  80 })
  81
  82 #define bitrev16(x) \
  83 ({                      \
  84         u16 __x = x;    \
  85         __builtin_constant_p(__x) ?     \
  86         __constant_bitrev16(__x) :                      \
  87         __bitrev16(__x);                                \
  88  })
  89
  90 #define bitrev8x4(x) \
  91 ({                      \
  92         u32 __x = x;    \
  93         __builtin_constant_p(__x) ?     \
  94         __constant_bitrev8x4(__x) :                     \
  95         __bitrev8x4(__x);                               \
  96  })
  97
  98 #define bitrev8(x) \
  99 ({                      \
 100         u8 __x = x;     \
 101         __builtin_constant_p(__x) ?     \
 102         __constant_bitrev8(__x) :                       \
 103         __bitrev8(__x)  ;                       \
 104  })
 105 #endif /* _LINUX_BITREV_H */