source: rtems-libbsd/rtemsbsd/include/machine/bitstring.h @ fb2aa6e

/*-
 * Copyright (c) 1982, 1986, 1991, 1993, 1994
 *      The Regents of the University of California.  All rights reserved.
 * (c) UNIX System Laboratories, Inc.
 * All or some portions of this file are derived from material licensed
 * to the University of California by American Telephone and Telegraph
 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
 * the permission of UNIX System Laboratories, Inc.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *      @(#)types.h     8.6 (Berkeley) 2/19/95
 * $FreeBSD$
 */

#ifndef _RTEMS_BSD_MACHINE_BITSTRING_H_
#define _RTEMS_BSD_MACHINE_BITSTRING_H_

#ifndef _SYS_BITSTRING_H_
#error "the header file <sys/bitstring.h> must be included first"
#endif

#ifdef __POPCNT__
#define __bitcount64(x) __builtin_popcountll((__uint64_t)(x))
#define __bitcount32(x) __builtin_popcount((__uint32_t)(x))
#define __bitcount16(x) __builtin_popcount((__uint16_t)(x))
#define __bitcountl(x)  __builtin_popcountl((unsigned long)(x))
#define __bitcount(x)   __builtin_popcount((unsigned int)(x))
#else
/*
 * Population count algorithm using SWAR approach
 * - "SIMD Within A Register".
 */
static __inline __uint16_t
__bitcount16(__uint16_t _x)
{

        _x = (_x & 0x5555) + ((_x & 0xaaaa) >> 1);
        _x = (_x & 0x3333) + ((_x & 0xcccc) >> 2);
        _x = (_x + (_x >> 4)) & 0x0f0f;
        _x = (_x + (_x >> 8)) & 0x00ff;
        return (_x);
}

static __inline __uint32_t
__bitcount32(__uint32_t _x)
{

        _x = (_x & 0x55555555) + ((_x & 0xaaaaaaaa) >> 1);
        _x = (_x & 0x33333333) + ((_x & 0xcccccccc) >> 2);
        _x = (_x + (_x >> 4)) & 0x0f0f0f0f;
        _x = (_x + (_x >> 8));
        _x = (_x + (_x >> 16)) & 0x000000ff;
        return (_x);
}

#ifdef __LP64__
static __inline __uint64_t
__bitcount64(__uint64_t _x)
{

        _x = (_x & 0x5555555555555555) + ((_x & 0xaaaaaaaaaaaaaaaa) >> 1);
        _x = (_x & 0x3333333333333333) + ((_x & 0xcccccccccccccccc) >> 2);
        _x = (_x + (_x >> 4)) & 0x0f0f0f0f0f0f0f0f;
        _x = (_x + (_x >> 8));
        _x = (_x + (_x >> 16));
        _x = (_x + (_x >> 32)) & 0x000000ff;
        return (_x);
}

#define __bitcountl(x)  __bitcount64((unsigned long)(x))
#else
static __inline __uint64_t
__bitcount64(__uint64_t _x)
{

        return (__bitcount32(_x >> 32) + __bitcount32(_x));
}

#define __bitcountl(x)  __bitcount32((unsigned long)(x))
#endif
#define __bitcount(x)   __bitcount32((unsigned int)(x))
#endif

#endif /* !_RTEMS_BSD_MACHINE_BITSTRING_H_ */