| 1 | #ifndef _LINUX_BITOPS_H |
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| 2 | #define _LINUX_BITOPS_H |
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| 3 | #include <asm/types.h> |
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| 4 | |
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| 5 | /* |
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| 6 | * ffs: find first bit set. This is defined the same way as |
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| 7 | * the libc and compiler builtin ffs routines, therefore |
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| 8 | * differs in spirit from the above ffz (man ffs). |
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| 9 | */ |
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| 10 | |
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| 11 | static inline int generic_ffs(int x) |
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| 12 | { |
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| 13 | int r = 1; |
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| 14 | |
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| 15 | if (!x) |
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| 16 | return 0; |
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| 17 | if (!(x & 0xffff)) { |
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| 18 | x >>= 16; |
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| 19 | r += 16; |
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| 20 | } |
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| 21 | if (!(x & 0xff)) { |
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| 22 | x >>= 8; |
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| 23 | r += 8; |
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| 24 | } |
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| 25 | if (!(x & 0xf)) { |
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| 26 | x >>= 4; |
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| 27 | r += 4; |
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| 28 | } |
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| 29 | if (!(x & 3)) { |
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| 30 | x >>= 2; |
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| 31 | r += 2; |
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| 32 | } |
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| 33 | if (!(x & 1)) { |
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| 34 | x >>= 1; |
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| 35 | r += 1; |
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| 36 | } |
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| 37 | return r; |
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| 38 | } |
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| 39 | |
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| 40 | /* |
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| 41 | * fls: find last bit set. |
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| 42 | */ |
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| 43 | |
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| 44 | static __inline__ int generic_fls(int x) |
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| 45 | { |
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| 46 | int r = 32; |
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| 47 | |
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| 48 | if (!x) |
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| 49 | return 0; |
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| 50 | if (!(x & 0xffff0000u)) { |
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| 51 | x <<= 16; |
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| 52 | r -= 16; |
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| 53 | } |
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| 54 | if (!(x & 0xff000000u)) { |
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| 55 | x <<= 8; |
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| 56 | r -= 8; |
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| 57 | } |
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| 58 | if (!(x & 0xf0000000u)) { |
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| 59 | x <<= 4; |
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| 60 | r -= 4; |
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| 61 | } |
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| 62 | if (!(x & 0xc0000000u)) { |
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| 63 | x <<= 2; |
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| 64 | r -= 2; |
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| 65 | } |
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| 66 | if (!(x & 0x80000000u)) { |
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| 67 | x <<= 1; |
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| 68 | r -= 1; |
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| 69 | } |
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| 70 | return r; |
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| 71 | } |
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| 72 | |
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| 73 | /* |
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| 74 | * Include this here because some architectures need generic_ffs/fls in |
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| 75 | * scope |
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| 76 | */ |
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| 77 | #include <asm/bitops.h> |
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| 78 | |
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| 79 | static __inline__ int get_bitmask_order(unsigned int count) |
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| 80 | { |
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| 81 | int order; |
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| 82 | |
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| 83 | order = fls(count); |
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| 84 | return order; /* We could be slightly more clever with -1 here... */ |
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| 85 | } |
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| 86 | |
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| 87 | /* |
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| 88 | * hweightN: returns the hamming weight (i.e. the number |
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| 89 | * of bits set) of a N-bit word |
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| 90 | */ |
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| 91 | |
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| 92 | static inline unsigned int generic_hweight32(unsigned int w) |
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| 93 | { |
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| 94 | unsigned int res = (w & 0x55555555) + ((w >> 1) & 0x55555555); |
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| 95 | res = (res & 0x33333333) + ((res >> 2) & 0x33333333); |
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| 96 | res = (res & 0x0F0F0F0F) + ((res >> 4) & 0x0F0F0F0F); |
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| 97 | res = (res & 0x00FF00FF) + ((res >> 8) & 0x00FF00FF); |
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| 98 | return (res & 0x0000FFFF) + ((res >> 16) & 0x0000FFFF); |
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| 99 | } |
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| 100 | |
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| 101 | static inline unsigned int generic_hweight16(unsigned int w) |
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| 102 | { |
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| 103 | unsigned int res = (w & 0x5555) + ((w >> 1) & 0x5555); |
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| 104 | res = (res & 0x3333) + ((res >> 2) & 0x3333); |
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| 105 | res = (res & 0x0F0F) + ((res >> 4) & 0x0F0F); |
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| 106 | return (res & 0x00FF) + ((res >> 8) & 0x00FF); |
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| 107 | } |
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| 108 | |
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| 109 | static inline unsigned int generic_hweight8(unsigned int w) |
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| 110 | { |
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| 111 | unsigned int res = (w & 0x55) + ((w >> 1) & 0x55); |
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| 112 | res = (res & 0x33) + ((res >> 2) & 0x33); |
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| 113 | return (res & 0x0F) + ((res >> 4) & 0x0F); |
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| 114 | } |
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| 115 | |
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| 116 | static inline unsigned long generic_hweight64(__u64 w) |
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| 117 | { |
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| 118 | #if BITS_PER_LONG < 64 |
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| 119 | return generic_hweight32((unsigned int)(w >> 32)) + |
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| 120 | generic_hweight32((unsigned int)w); |
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| 121 | #else |
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| 122 | __u64 res; |
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| 123 | res = (w & 0x5555555555555555ul) + ((w >> 1) & 0x5555555555555555ul); |
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| 124 | res = (res & 0x3333333333333333ul) + ((res >> 2) & 0x3333333333333333ul); |
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| 125 | res = (res & 0x0F0F0F0F0F0F0F0Ful) + ((res >> 4) & 0x0F0F0F0F0F0F0F0Ful); |
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| 126 | res = (res & 0x00FF00FF00FF00FFul) + ((res >> 8) & 0x00FF00FF00FF00FFul); |
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| 127 | res = (res & 0x0000FFFF0000FFFFul) + ((res >> 16) & 0x0000FFFF0000FFFFul); |
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| 128 | return (res & 0x00000000FFFFFFFFul) + ((res >> 32) & 0x00000000FFFFFFFFul); |
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| 129 | #endif |
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| 130 | } |
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| 131 | |
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| 132 | static inline unsigned long hweight_long(unsigned long w) |
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| 133 | { |
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| 134 | return sizeof(w) == 4 ? generic_hweight32(w) : generic_hweight64(w); |
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| 135 | } |
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| 136 | |
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| 137 | /* |
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| 138 | * rol32 - rotate a 32-bit value left |
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| 139 | * |
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| 140 | * @word: value to rotate |
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| 141 | * @shift: bits to roll |
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| 142 | */ |
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| 143 | static inline __u32 rol32(__u32 word, unsigned int shift) |
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| 144 | { |
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| 145 | return (word << shift) | (word >> (32 - shift)); |
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| 146 | } |
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| 147 | |
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| 148 | /* |
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| 149 | * ror32 - rotate a 32-bit value right |
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| 150 | * |
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| 151 | * @word: value to rotate |
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| 152 | * @shift: bits to roll |
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| 153 | */ |
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| 154 | static inline __u32 ror32(__u32 word, unsigned int shift) |
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| 155 | { |
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| 156 | return (word >> shift) | (word << (32 - shift)); |
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| 157 | } |
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| 158 | |
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| 159 | #endif |
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