diff options
| author | Ingo Molnar <mingo@elte.hu> | 2010-03-04 11:51:29 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2010-03-04 11:51:29 +0100 |
| commit | e02c4fd3142dfb9412531bbfabd510a2a7c6ea46 (patch) | |
| tree | 61b64506b2c016e050f940a89d1ffd36b7c00fdf /include/linux/bitops.h | |
| parent | ae1f30384baef4056438d81b305a6a5199b0d16c (diff) | |
| parent | ac91d85456372a90af5b85eb6620fd2efb1e431b (diff) | |
Merge branch 'tip/tracing/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into tracing/urgent
Diffstat (limited to 'include/linux/bitops.h')
| -rw-r--r-- | include/linux/bitops.h | 29 |
1 files changed, 27 insertions, 2 deletions
diff --git a/include/linux/bitops.h b/include/linux/bitops.h index c05a29cb9bb2..25b8b2f33ae9 100644 --- a/include/linux/bitops.h +++ b/include/linux/bitops.h @@ -25,7 +25,7 @@ static __inline__ int get_bitmask_order(unsigned int count) { int order; - + order = fls(count); return order; /* We could be slightly more clever with -1 here... */ } @@ -33,7 +33,7 @@ static __inline__ int get_bitmask_order(unsigned int count) static __inline__ int get_count_order(unsigned int count) { int order; - + order = fls(count) - 1; if (count & (count - 1)) order++; @@ -45,6 +45,31 @@ static inline unsigned long hweight_long(unsigned long w) return sizeof(w) == 4 ? hweight32(w) : hweight64(w); } +/* + * Clearly slow versions of the hweightN() functions, their benefit is + * of course compile time evaluation of constant arguments. + */ +#define HWEIGHT8(w) \ + ( BUILD_BUG_ON_ZERO(!__builtin_constant_p(w)) + \ + (!!((w) & (1ULL << 0))) + \ + (!!((w) & (1ULL << 1))) + \ + (!!((w) & (1ULL << 2))) + \ + (!!((w) & (1ULL << 3))) + \ + (!!((w) & (1ULL << 4))) + \ + (!!((w) & (1ULL << 5))) + \ + (!!((w) & (1ULL << 6))) + \ + (!!((w) & (1ULL << 7))) ) + +#define HWEIGHT16(w) (HWEIGHT8(w) + HWEIGHT8((w) >> 8)) +#define HWEIGHT32(w) (HWEIGHT16(w) + HWEIGHT16((w) >> 16)) +#define HWEIGHT64(w) (HWEIGHT32(w) + HWEIGHT32((w) >> 32)) + +/* + * Type invariant version that simply casts things to the + * largest type. + */ +#define HWEIGHT(w) HWEIGHT64((u64)(w)) + /** * rol32 - rotate a 32-bit value left * @word: value to rotate |