1 #ifndef _LINUX_BITOPS_H 2 #define _LINUX_BITOPS_H 3 4 #include <asm/types.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 generic_ffs(int x)12static 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 (most-significant) bit set 43 * @x: the word to search 44 * 45 * This is defined the same way as ffs. 46 * Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32. 47 */ generic_fls(int x)48static inline int generic_fls(int x) 49 { 50 int r = 32; 51 52 if (!x) 53 return 0; 54 if (!(x & 0xffff0000u)) { 55 x <<= 16; 56 r -= 16; 57 } 58 if (!(x & 0xff000000u)) { 59 x <<= 8; 60 r -= 8; 61 } 62 if (!(x & 0xf0000000u)) { 63 x <<= 4; 64 r -= 4; 65 } 66 if (!(x & 0xc0000000u)) { 67 x <<= 2; 68 r -= 2; 69 } 70 if (!(x & 0x80000000u)) { 71 x <<= 1; 72 r -= 1; 73 } 74 return r; 75 } 76 77 78 /* 79 * hweightN: returns the hamming weight (i.e. the number 80 * of bits set) of a N-bit word 81 */ 82 generic_hweight32(unsigned int w)83static inline unsigned int generic_hweight32(unsigned int w) 84 { 85 unsigned int res = (w & 0x55555555) + ((w >> 1) & 0x55555555); 86 res = (res & 0x33333333) + ((res >> 2) & 0x33333333); 87 res = (res & 0x0F0F0F0F) + ((res >> 4) & 0x0F0F0F0F); 88 res = (res & 0x00FF00FF) + ((res >> 8) & 0x00FF00FF); 89 return (res & 0x0000FFFF) + ((res >> 16) & 0x0000FFFF); 90 } 91 generic_hweight16(unsigned int w)92static inline unsigned int generic_hweight16(unsigned int w) 93 { 94 unsigned int res = (w & 0x5555) + ((w >> 1) & 0x5555); 95 res = (res & 0x3333) + ((res >> 2) & 0x3333); 96 res = (res & 0x0F0F) + ((res >> 4) & 0x0F0F); 97 return (res & 0x00FF) + ((res >> 8) & 0x00FF); 98 } 99 generic_hweight8(unsigned int w)100static inline unsigned int generic_hweight8(unsigned int w) 101 { 102 unsigned int res = (w & 0x55) + ((w >> 1) & 0x55); 103 res = (res & 0x33) + ((res >> 2) & 0x33); 104 return (res & 0x0F) + ((res >> 4) & 0x0F); 105 } 106 107 #define BIT_MASK(nr) (1UL << ((nr) % BITS_PER_LONG)) 108 #define BIT_WORD(nr) ((nr) / BITS_PER_LONG) 109 110 #include <asm/bitops.h> 111 112 /* linux/include/asm-generic/bitops/non-atomic.h */ 113 114 #ifndef PLATFORM__SET_BIT 115 # define __set_bit generic_set_bit 116 #endif 117 118 #ifndef PLATFORM__CLEAR_BIT 119 # define __clear_bit generic_clear_bit 120 #endif 121 122 #ifndef PLATFORM_FFS 123 # define ffs generic_ffs 124 #endif 125 126 #ifndef PLATFORM_FLS 127 # define fls generic_fls 128 #endif 129 130 /** 131 * __set_bit - Set a bit in memory 132 * @nr: the bit to set 133 * @addr: the address to start counting from 134 * 135 * Unlike set_bit(), this function is non-atomic and may be reordered. 136 * If it's called on the same region of memory simultaneously, the effect 137 * may be that only one operation succeeds. 138 */ generic_set_bit(int nr,volatile unsigned long * addr)139static inline void generic_set_bit(int nr, volatile unsigned long *addr) 140 { 141 unsigned long mask = BIT_MASK(nr); 142 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr); 143 144 *p |= mask; 145 } 146 generic_clear_bit(int nr,volatile unsigned long * addr)147static inline void generic_clear_bit(int nr, volatile unsigned long *addr) 148 { 149 unsigned long mask = BIT_MASK(nr); 150 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr); 151 152 *p &= ~mask; 153 } 154 155 #endif 156