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 #define __const_bitcount8(x) ( \
43 !!((x) & (1 << 0)) + \
44 !!((x) & (1 << 1)) + \
45 !!((x) & (1 << 2)) + \
46 !!((x) & (1 << 3)) + \
47 !!((x) & (1 << 4)) + \
48 !!((x) & (1 << 5)) + \
49 !!((x) & (1 << 6)) + \
50 !!((x) & (1 << 7)))
51
52 #define __const_bitcount16(x) ( \
53 __const_bitcount8(x) + \
54 __const_bitcount8((x) >> 8))
55
56 #define __const_bitcount32(x) ( \
57 __const_bitcount16(x) + \
58 __const_bitcount16((x) >> 16))
59
60 #define __const_bitcount64(x) ( \
61 __const_bitcount32(x) + \
62 __const_bitcount32((x) >> 32))
63
64 #ifdef __POPCNT__
65 #define __bitcount64(x) __builtin_popcountll((__uint64_t)(x))
66 #define __bitcount32(x) __builtin_popcount((__uint32_t)(x))
67 #define __bitcount16(x) __builtin_popcount((__uint16_t)(x))
68 #define __bitcountl(x) __builtin_popcountl((unsigned long)(x))
69 #define __bitcount(x) __builtin_popcount((unsigned int)(x))
70 #else
71 /*
72 * Population count algorithm using SWAR approach
73 * - "SIMD Within A Register".
74 */
75 static __inline __uint16_t
__bitcount16(__uint16_t _x)76 __bitcount16(__uint16_t _x)
77 {
78
79 _x = (_x & 0x5555) + ((_x & 0xaaaa) >> 1);
80 _x = (_x & 0x3333) + ((_x & 0xcccc) >> 2);
81 _x = (_x + (_x >> 4)) & 0x0f0f;
82 _x = (_x + (_x >> 8)) & 0x00ff;
83 return (_x);
84 }
85
86 static __inline __uint32_t
__bitcount32(__uint32_t _x)87 __bitcount32(__uint32_t _x)
88 {
89
90 _x = (_x & 0x55555555) + ((_x & 0xaaaaaaaa) >> 1);
91 _x = (_x & 0x33333333) + ((_x & 0xcccccccc) >> 2);
92 _x = (_x + (_x >> 4)) & 0x0f0f0f0f;
93 _x = (_x + (_x >> 8));
94 _x = (_x + (_x >> 16)) & 0x000000ff;
95 return (_x);
96 }
97
98 #ifdef __LP64__
99 static __inline __uint64_t
__bitcount64(__uint64_t _x)100 __bitcount64(__uint64_t _x)
101 {
102
103 _x = (_x & 0x5555555555555555) + ((_x & 0xaaaaaaaaaaaaaaaa) >> 1);
104 _x = (_x & 0x3333333333333333) + ((_x & 0xcccccccccccccccc) >> 2);
105 _x = (_x + (_x >> 4)) & 0x0f0f0f0f0f0f0f0f;
106 _x = (_x + (_x >> 8));
107 _x = (_x + (_x >> 16));
108 _x = (_x + (_x >> 32)) & 0x000000ff;
109 return (_x);
110 }
111
112 #define __bitcountl(x) __bitcount64((unsigned long)(x))
113 #else
114 static __inline __uint64_t
__bitcount64(__uint64_t _x)115 __bitcount64(__uint64_t _x)
116 {
117
118 return (__bitcount32(_x >> 32) + __bitcount32(_x));
119 }
120
121 #define __bitcountl(x) __bitcount32((unsigned long)(x))
122 #endif
123 #define __bitcount(x) __bitcount32((unsigned int)(x))
124 #endif
125
126 #endif /* !_SYS_BITCOUNT_H_ */
127