diff options
Diffstat (limited to 'include/asm-x86_64/bitops.h')
| -rw-r--r-- | include/asm-x86_64/bitops.h | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/include/asm-x86_64/bitops.h b/include/asm-x86_64/bitops.h index 05a0d374404..a4d5d090945 100644 --- a/include/asm-x86_64/bitops.h +++ b/include/asm-x86_64/bitops.h @@ -340,6 +340,20 @@ static __inline__ unsigned long __ffs(unsigned long word) return word; } +/* + * __fls: find last bit set. + * @word: The word to search + * + * Undefined if no zero exists, so code should check against ~0UL first. + */ +static __inline__ unsigned long __fls(unsigned long word) +{ + __asm__("bsrq %1,%0" + :"=r" (word) + :"rm" (word)); + return word; +} + #ifdef __KERNEL__ static inline int sched_find_first_bit(const unsigned long *b) @@ -370,6 +384,19 @@ static __inline__ int ffs(int x) } /** + * fls64 - find last bit set in 64 bit word + * @x: the word to search + * + * This is defined the same way as fls. + */ +static __inline__ int fls64(__u64 x) +{ + if (x == 0) + return 0; + return __fls(x) + 1; +} + +/** * hweightN - returns the hamming weight of a N-bit word * @x: the word to weigh * |