projects / thirdparty / xfsprogs-dev.git / blame
| Commit | Line | Data |
|---|---|---|
| 5e656dbb BN |
1 | #ifndef __BITOPS_H__ |
| 2 | #define __BITOPS_H__ | |
| 3 | ||
| 4 | /* | |
| 5 | * fls: find last bit set. | |
| 6 | */ | |
| 7 | ||
| 5121281b | 8 | #ifndef HAVE_FLS |
| 5e656dbb BN |
9 | static inline int fls(int x) |
| 10 | { | |
| 11 | int r = 32; | |
| 12 | ||
| 13 | if (!x) | |
| 14 | return 0; | |
| 15 | if (!(x & 0xffff0000u)) { | |
| 16 | x <<= 16; | |
| 17 | r -= 16; | |
| 18 | } | |
| 19 | if (!(x & 0xff000000u)) { | |
| 20 | x <<= 8; | |
| 21 | r -= 8; | |
| 22 | } | |
| 23 | if (!(x & 0xf0000000u)) { | |
| 24 | x <<= 4; | |
| 25 | r -= 4; | |
| 26 | } | |
| 27 | if (!(x & 0xc0000000u)) { | |
| 28 | x <<= 2; | |
| 29 | r -= 2; | |
| 30 | } | |
| 31 | if (!(x & 0x80000000u)) { | |
| 5e656dbb BN |
32 | r -= 1; |
| 33 | } | |
| 34 | return r; | |
| 35 | } | |
| 5121281b | 36 | #endif /* HAVE_FLS */ |
| 5e656dbb BN |
37 | |
| 38 | static inline int fls64(__u64 x) | |
| 39 | { | |
| 40 | __u32 h = x >> 32; | |
| 41 | if (h) | |
| 42 | return fls(h) + 32; | |
| 43 | return fls(x); | |
| 44 | } | |
| 45 | ||
| 46 | static inline unsigned fls_long(unsigned long l) | |
| 47 | { | |
| 48 | if (sizeof(l) == 4) | |
| 49 | return fls(l); | |
| 50 | return fls64(l); | |
| 51 | } | |
| 52 | ||
| 4071f725 DC |
53 | /* |
| 54 | * ffz: find first zero bit. | |
| 55 | * Result is undefined if no zero bit exists. | |
| 56 | */ | |
| 57 | #define ffz(x) ffs(~(x)) | |
| 58 | ||
| 5e656dbb | 59 | #endif |