projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 136abb32 AM |
1 | #ifndef _ASM_GENERIC_BITOPS_FLS_H_ |
| 2 | #define _ASM_GENERIC_BITOPS_FLS_H_ | |
| 3 | ||
| 4 | /** | |
| 5 | * fls - find last (most-significant) bit set | |
| 6 | * @x: the word to search | |
| 7 | * | |
| 8 | * This is defined the same way as ffs. | |
| 9 | * Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32. | |
| 10 | */ | |
| 11 | ||
| c8399943 | 12 | static __always_inline int fls(int x) |
| 136abb32 AM |
13 | { |
| 14 | int r = 32; | |
| 15 | ||
| 16 | if (!x) | |
| 17 | return 0; | |
| 18 | if (!(x & 0xffff0000u)) { | |
| 19 | x <<= 16; | |
| 20 | r -= 16; | |
| 21 | } | |
| 22 | if (!(x & 0xff000000u)) { | |
| 23 | x <<= 8; | |
| 24 | r -= 8; | |
| 25 | } | |
| 26 | if (!(x & 0xf0000000u)) { | |
| 27 | x <<= 4; | |
| 28 | r -= 4; | |
| 29 | } | |
| 30 | if (!(x & 0xc0000000u)) { | |
| 31 | x <<= 2; | |
| 32 | r -= 2; | |
| 33 | } | |
| 34 | if (!(x & 0x80000000u)) { | |
| 35 | x <<= 1; | |
| 36 | r -= 1; | |
| 37 | } | |
| 38 | return r; | |
| 39 | } | |
| 40 | ||
| 41 | #endif /* _ASM_GENERIC_BITOPS_FLS_H_ */ |