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41 lines
1007 B
C
41 lines
1007 B
C
/*
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* BIRD Library -- Generic Bit Operations
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*
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* (c) 1998 Martin Mares <mj@ucw.cz>
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*
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* Can be freely distributed and used under the terms of the GNU GPL.
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*/
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#ifndef _BIRD_BITOPTS_H_
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#define _BIRD_BITOPTS_H_
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#include "sysdep/config.h"
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/*
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* Bit mask operations:
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*
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* u32_mkmask Make bit mask consisting of <n> consecutive ones
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* from the left and the rest filled with zeroes.
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* E.g., u32_mkmask(5) = 0xf8000000.
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* u32_masklen Inverse operation to u32_mkmask, -1 if not a bitmask.
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*/
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u32 u32_mkmask(uint n);
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uint u32_masklen(u32 x);
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u32 u32_log2(u32 v);
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u32 u32_bitflip(u32 n);
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static inline u32 u32_hash(u32 v) { return v * 2902958171u; }
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static inline u8 u32_popcount(u32 v) { return __builtin_popcount(v); }
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static inline u8 u64_popcount(u64 v) { return __builtin_popcountll(v); }
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static inline int u32_clz(u32 v) { return __builtin_clz(v); }
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static inline int u32_ctz(u32 v) { return __builtin_ctz(v); }
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static inline int uint_is_pow2(uint n) { return n && !(n & (n-1)); }
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#endif
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