diff options
| author |   Alexander van Heukelum <heukelum@mailshack.com> | 2008-03-15 18:32:36 +0100 |
|---|---|---|
| committer |   Ingo Molnar <mingo@elte.hu> | 2008-04-26 19:21:16 +0200 |
| commit | d57594c203b1e7b54373080a797f0cbfa4aade68 (patch) | |
| tree | 61610af68fc93280fb0be00a4f1b523715bef3db /include/asm-generic/bitops | |
| parent | generic: implement __fls on all 64-bit archs (diff) | |
| download | linux-dev-d57594c203b1e7b54373080a797f0cbfa4aade68.tar.xz linux-dev-d57594c203b1e7b54373080a797f0cbfa4aade68.zip | |
bitops: use __fls for fls64 on 64-bit archs
Use __fls for fls64 on 64-bit archs. The implementation for
64-bit archs is moved from x86_64 to asm-generic.
Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'include/asm-generic/bitops')
| -rw-r--r-- | include/asm-generic/bitops/fls64.h | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/include/asm-generic/bitops/fls64.h b/include/asm-generic/bitops/fls64.h index 1b6b17ce2428..86d403f8b256 100644 --- a/include/asm-generic/bitops/fls64.h +++ b/include/asm-generic/bitops/fls64.h @@ -3,6 +3,18 @@ #include <asm/types.h> +/** + * fls64 - find last set bit in a 64-bit word + * @x: the word to search + * + * This is defined in a similar way as the libc and compiler builtin + * ffsll, but returns the position of the most significant set bit. + * + * fls64(value) returns 0 if value is 0 or the position of the last + * set bit if value is nonzero. The last (most significant) bit is + * at position 64. + */ +#if BITS_PER_LONG == 32 static inline int fls64(__u64 x) { __u32 h = x >> 32; @@ -10,5 +22,15 @@ static inline int fls64(__u64 x) return fls(h) + 32; return fls(x); } +#elif BITS_PER_LONG == 64 +static inline int fls64(__u64 x) +{ + if (x == 0) + return 0; + return __fls(x) + 1; +} +#else +#error BITS_PER_LONG not 32 or 64 +#endif #endif /* _ASM_GENERIC_BITOPS_FLS64_H_ */ |