Annotation of embedaddon/bird2/lib/bitops.h, revision 1.1.1.1
1.1 misho 1: /*
2: * BIRD Library -- Generic Bit Operations
3: *
4: * (c) 1998 Martin Mares <mj@ucw.cz>
5: *
6: * Can be freely distributed and used under the terms of the GNU GPL.
7: */
8:
9: #ifndef _BIRD_BITOPTS_H_
10: #define _BIRD_BITOPTS_H_
11:
12: #include "sysdep/config.h"
13:
14: /*
15: * Bit mask operations:
16: *
17: * u32_mkmask Make bit mask consisting of <n> consecutive ones
18: * from the left and the rest filled with zeroes.
19: * E.g., u32_mkmask(5) = 0xf8000000.
20: * u32_masklen Inverse operation to u32_mkmask, -1 if not a bitmask.
21: */
22:
23: u32 u32_mkmask(uint n);
24: uint u32_masklen(u32 x);
25:
26: u32 u32_log2(u32 v);
27:
28: static inline u32 u32_hash(u32 v) { return v * 2902958171u; }
29:
30: static inline u8 u32_popcount(u32 v) { return __builtin_popcount(v); }
31:
32: static inline int uint_is_pow2(uint n) { return n && !(n & (n-1)); }
33:
34: #endif
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