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iof-bird / bird-2.0.1 / lib / bitops.h @ 6b3f1a54

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/*
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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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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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#endif