Details | Last modification | View Log | RSS feed
| Rev | Author | Line No. | Line |
|---|---|---|---|
| 422 | giacomo | 1 | #ifndef _LINUX_BITOPS_H |
| 2 | #define _LINUX_BITOPS_H |
||
| 3 | #include <asm/types.h> |
||
| 4 | #include <asm/bitops.h> |
||
| 5 | |||
| 6 | /* |
||
| 7 | * ffs: find first bit set. This is defined the same way as |
||
| 8 | * the libc and compiler builtin ffs routines, therefore |
||
| 9 | * differs in spirit from the above ffz (man ffs). |
||
| 10 | */ |
||
| 11 | |||
| 12 | static inline int generic_ffs(int x) |
||
| 13 | { |
||
| 14 | int r = 1; |
||
| 15 | |||
| 16 | if (!x) |
||
| 17 | return 0; |
||
| 18 | if (!(x & 0xffff)) { |
||
| 19 | x >>= 16; |
||
| 20 | r += 16; |
||
| 21 | } |
||
| 22 | if (!(x & 0xff)) { |
||
| 23 | x >>= 8; |
||
| 24 | r += 8; |
||
| 25 | } |
||
| 26 | if (!(x & 0xf)) { |
||
| 27 | x >>= 4; |
||
| 28 | r += 4; |
||
| 29 | } |
||
| 30 | if (!(x & 3)) { |
||
| 31 | x >>= 2; |
||
| 32 | r += 2; |
||
| 33 | } |
||
| 34 | if (!(x & 1)) { |
||
| 35 | x >>= 1; |
||
| 36 | r += 1; |
||
| 37 | } |
||
| 38 | return r; |
||
| 39 | } |
||
| 40 | |||
| 41 | /* |
||
| 42 | * fls: find last bit set. |
||
| 43 | */ |
||
| 44 | |||
| 45 | extern __inline__ int generic_fls(int x) |
||
| 46 | { |
||
| 47 | int r = 32; |
||
| 48 | |||
| 49 | if (!x) |
||
| 50 | return 0; |
||
| 51 | if (!(x & 0xffff0000u)) { |
||
| 52 | x <<= 16; |
||
| 53 | r -= 16; |
||
| 54 | } |
||
| 55 | if (!(x & 0xff000000u)) { |
||
| 56 | x <<= 8; |
||
| 57 | r -= 8; |
||
| 58 | } |
||
| 59 | if (!(x & 0xf0000000u)) { |
||
| 60 | x <<= 4; |
||
| 61 | r -= 4; |
||
| 62 | } |
||
| 63 | if (!(x & 0xc0000000u)) { |
||
| 64 | x <<= 2; |
||
| 65 | r -= 2; |
||
| 66 | } |
||
| 67 | if (!(x & 0x80000000u)) { |
||
| 68 | x <<= 1; |
||
| 69 | r -= 1; |
||
| 70 | } |
||
| 71 | return r; |
||
| 72 | } |
||
| 73 | |||
| 74 | extern __inline__ int get_bitmask_order(unsigned int count) |
||
| 75 | { |
||
| 76 | int order; |
||
| 77 | |||
| 78 | order = fls(count); |
||
| 79 | return order; /* We could be slightly more clever with -1 here... */ |
||
| 80 | } |
||
| 81 | |||
| 82 | /* |
||
| 83 | * hweightN: returns the hamming weight (i.e. the number |
||
| 84 | * of bits set) of a N-bit word |
||
| 85 | */ |
||
| 86 | |||
| 87 | static inline unsigned int generic_hweight32(unsigned int w) |
||
| 88 | { |
||
| 89 | unsigned int res = (w & 0x55555555) + ((w >> 1) & 0x55555555); |
||
| 90 | res = (res & 0x33333333) + ((res >> 2) & 0x33333333); |
||
| 91 | res = (res & 0x0F0F0F0F) + ((res >> 4) & 0x0F0F0F0F); |
||
| 92 | res = (res & 0x00FF00FF) + ((res >> 8) & 0x00FF00FF); |
||
| 93 | return (res & 0x0000FFFF) + ((res >> 16) & 0x0000FFFF); |
||
| 94 | } |
||
| 95 | |||
| 96 | static inline unsigned int generic_hweight16(unsigned int w) |
||
| 97 | { |
||
| 98 | unsigned int res = (w & 0x5555) + ((w >> 1) & 0x5555); |
||
| 99 | res = (res & 0x3333) + ((res >> 2) & 0x3333); |
||
| 100 | res = (res & 0x0F0F) + ((res >> 4) & 0x0F0F); |
||
| 101 | return (res & 0x00FF) + ((res >> 8) & 0x00FF); |
||
| 102 | } |
||
| 103 | |||
| 104 | static inline unsigned int generic_hweight8(unsigned int w) |
||
| 105 | { |
||
| 106 | unsigned int res = (w & 0x55) + ((w >> 1) & 0x55); |
||
| 107 | res = (res & 0x33) + ((res >> 2) & 0x33); |
||
| 108 | return (res & 0x0F) + ((res >> 4) & 0x0F); |
||
| 109 | } |
||
| 110 | |||
| 111 | static inline unsigned long generic_hweight64(__u64 w) |
||
| 112 | { |
||
| 113 | #if BITS_PER_LONG < 64 |
||
| 114 | return generic_hweight32((unsigned int)(w >> 32)) + |
||
| 115 | generic_hweight32((unsigned int)w); |
||
| 116 | #else |
||
| 117 | u64 res; |
||
| 118 | res = (w & 0x5555555555555555) + ((w >> 1) & 0x5555555555555555); |
||
| 119 | res = (res & 0x3333333333333333) + ((res >> 2) & 0x3333333333333333); |
||
| 120 | res = (res & 0x0F0F0F0F0F0F0F0F) + ((res >> 4) & 0x0F0F0F0F0F0F0F0F); |
||
| 121 | res = (res & 0x00FF00FF00FF00FF) + ((res >> 8) & 0x00FF00FF00FF00FF); |
||
| 122 | res = (res & 0x0000FFFF0000FFFF) + ((res >> 16) & 0x0000FFFF0000FFFF); |
||
| 123 | return (res & 0x00000000FFFFFFFF) + ((res >> 32) & 0x00000000FFFFFFFF); |
||
| 124 | #endif |
||
| 125 | } |
||
| 126 | |||
| 127 | static inline unsigned long hweight_long(unsigned long w) |
||
| 128 | { |
||
| 129 | return sizeof(w) == 4 ? generic_hweight32(w) : generic_hweight64(w); |
||
| 130 | } |
||
| 131 | |||
| 132 | #endif |