1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1982, 1986, 1991, 1993, 1994
5 * The Regents of the University of California. All rights reserved.
6 * (c) UNIX System Laboratories, Inc.
7 * All or some portions of this file are derived from material licensed
8 * to the University of California by American Telephone and Telegraph
9 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
10 * the permission of UNIX System Laboratories, Inc.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 */
36
37#ifndef _SYS_BITCOUNT_H_
38#define _SYS_BITCOUNT_H_
39
40#include <sys/_types.h>
41
42#ifdef __POPCNT__
43#define __bitcount64(x) __builtin_popcountll((__uint64_t)(x))
44#define __bitcount32(x) __builtin_popcount((__uint32_t)(x))
45#define __bitcount16(x) __builtin_popcount((__uint16_t)(x))
46#define __bitcountl(x) __builtin_popcountl((unsigned long)(x))
47#define __bitcount(x) __builtin_popcount((unsigned int)(x))
48#else
49/*
50 * Population count algorithm using SWAR approach
51 * - "SIMD Within A Register".
52 */
53static __inline __uint16_t
54__bitcount16(__uint16_t _x)
55{
56
57 _x = (_x & 0x5555) + ((_x & 0xaaaa) >> 1);
58 _x = (_x & 0x3333) + ((_x & 0xcccc) >> 2);
59 _x = (_x + (_x >> 4)) & 0x0f0f;
60 _x = (_x + (_x >> 8)) & 0x00ff;
61 return (_x);
62}
63
64static __inline __uint32_t
65__bitcount32(__uint32_t _x)
66{
67
68 _x = (_x & 0x55555555) + ((_x & 0xaaaaaaaa) >> 1);
69 _x = (_x & 0x33333333) + ((_x & 0xcccccccc) >> 2);
70 _x = (_x + (_x >> 4)) & 0x0f0f0f0f;
71 _x = (_x + (_x >> 8));
72 _x = (_x + (_x >> 16)) & 0x000000ff;
73 return (_x);
74}
75
76#ifdef __LP64__
77static __inline __uint64_t
78__bitcount64(__uint64_t _x)
79{
80
81 _x = (_x & 0x5555555555555555) + ((_x & 0xaaaaaaaaaaaaaaaa) >> 1);
82 _x = (_x & 0x3333333333333333) + ((_x & 0xcccccccccccccccc) >> 2);
83 _x = (_x + (_x >> 4)) & 0x0f0f0f0f0f0f0f0f;
84 _x = (_x + (_x >> 8));
85 _x = (_x + (_x >> 16));
86 _x = (_x + (_x >> 32)) & 0x000000ff;
87 return (_x);
88}
89
90#define __bitcountl(x) __bitcount64((unsigned long)(x))
91#else
92static __inline __uint64_t
93__bitcount64(__uint64_t _x)
94{
95
96 return (__bitcount32(_x >> 32) + __bitcount32(_x));
97}
98
99#define __bitcountl(x) __bitcount32((unsigned long)(x))
100#endif
101#define __bitcount(x) __bitcount32((unsigned int)(x))
102#endif
103
104#endif /* !_SYS_BITCOUNT_H_ */