[thirdparty/bird.git] / lib / bitops.h

/*
 *	BIRD Library -- Generic Bit Operations
 *
 *	(c) 1998 Martin Mares <mj@ucw.cz>
 *
 *	Can be freely distributed and used under the terms of the GNU GPL.
 */

#ifndef _BIRD_BITOPTS_H_
#define _BIRD_BITOPTS_H_

#include "sysdep/config.h"

/*
 *	Bit mask operations:
 *
 *	u32_mkmask	Make bit mask consisting of <n> consecutive ones
 *			from the left and the rest filled with zeroes.
 *			E.g., u32_mkmask(5) = 0xf8000000.
 *	u32_masklen	Inverse operation to u32_mkmask, -1 if not a bitmask.
 */

u32 u32_mkmask(uint n);
uint u32_masklen(u32 x);

u32 u32_log2(u32 v);

static inline u32 u32_hash(u32 v) { return v * 2902958171u; }

static inline u8 u32_popcount(u32 v) { return __builtin_popcount(v); }

static inline int u32_clz(u32 v) { return __builtin_clz(v); }
static inline int u32_ctz(u32 v) { return __builtin_ctz(v); }

static inline int uint_is_pow2(uint n) { return n && !(n & (n-1)); }

#endif
Commit	Line	Data
18c8241a MM	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
e7d2ac44 OZ	9	#ifndef _BIRD_BITOPTS_H_
	10	#define _BIRD_BITOPTS_H_
	11
9b0a0ba9 OZ	12	#include "sysdep/config.h"
9b0a0ba9 OZ	13
18c8241a MM	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
ae80a2de	23	u32 u32_mkmask(uint n);
fe9f1a6d	24	uint u32_masklen(u32 x);
b1a597e0 OZ	25
b1a597e0 OZ	26	u32 u32_log2(u32 v);
e7d2ac44 OZ	27
	28	static inline u32 u32_hash(u32 v) { return v * 2902958171u; }
	29
937e75d8	30	static inline u8 u32_popcount(u32 v) { return __builtin_popcount(v); }
e7d2ac44	31
af02b83b OZ	32	static inline int u32_clz(u32 v) { return __builtin_clz(v); }
	33	static inline int u32_ctz(u32 v) { return __builtin_ctz(v); }
	34
4fa0e472 OZ	35	static inline int uint_is_pow2(uint n) { return n && !(n & (n-1)); }
4fa0e472 OZ	36
937e75d8	37	#endif