1 #ifndef _ASM_GENERIC_BITOPS___FLS_H_ 2 #define _ASM_GENERIC_BITOPS___FLS_H_ 3 4 #include <asm/types.h> 5 6 /** 7 * __fls - find last (most-significant) set bit in a long word 8 * @word: the word to search 9 * 10 * Undefined if no set bit exists, so code should check against 0 first. 11 */ 12 static __always_inline unsigned long __fls(unsigned long word) 13 { 14 int num = BITS_PER_LONG - 1; 15 16 #if BITS_PER_LONG == 64 17 if (!(word & (~0ul << 32))) { 18 num -= 32; 19 word <<= 32; 20 } 21 #endif 22 if (!(word & (~0ul << (BITS_PER_LONG-16)))) { 23 num -= 16; 24 word <<= 16; 25 } 26 if (!(word & (~0ul << (BITS_PER_LONG-8)))) { 27 num -= 8; 28 word <<= 8; 29 } 30 if (!(word & (~0ul << (BITS_PER_LONG-4)))) { 31 num -= 4; 32 word <<= 4; 33 } 34 if (!(word & (~0ul << (BITS_PER_LONG-2)))) { 35 num -= 2; 36 word <<= 2; 37 } 38 if (!(word & (~0ul << (BITS_PER_LONG-1)))) 39 num -= 1; 40 return num; 41 } 42 43 #endif /* _ASM_GENERIC_BITOPS___FLS_H_ */ 44