1 /* $NetBSD: bitops.h,v 1.11 2012/12/07 02:27:58 christos Exp $ */
2
3 /*-
4 * Copyright (c) 2007, 2010 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Christos Zoulas and Joerg Sonnenberger.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32 #ifndef COMPAT_BITOPS_H
33 #define COMPAT_BITOPS_H
34
35 #include <stdint.h>
36 #include "common.h"
37
38 /*
39 * Find First Set functions
40 */
41 #ifndef ffs32
42 static inline int __unused
ffs32(uint32_t _n)43 ffs32(uint32_t _n)
44 {
45 int _v;
46
47 if (!_n)
48 return 0;
49
50 _v = 1;
51 if ((_n & 0x0000FFFFU) == 0) {
52 _n >>= 16;
53 _v += 16;
54 }
55 if ((_n & 0x000000FFU) == 0) {
56 _n >>= 8;
57 _v += 8;
58 }
59 if ((_n & 0x0000000FU) == 0) {
60 _n >>= 4;
61 _v += 4;
62 }
63 if ((_n & 0x00000003U) == 0) {
64 _n >>= 2;
65 _v += 2;
66 }
67 if ((_n & 0x00000001U) == 0) {
68 //_n >>= 1;
69 _v += 1;
70 }
71 return _v;
72 }
73 #endif
74
75 #ifndef ffs64
76 static inline int __unused
ffs64(uint64_t _n)77 ffs64(uint64_t _n)
78 {
79 int _v;
80
81 if (!_n)
82 return 0;
83
84 _v = 1;
85 if ((_n & 0x00000000FFFFFFFFULL) == 0) {
86 _n >>= 32;
87 _v += 32;
88 }
89 if ((_n & 0x000000000000FFFFULL) == 0) {
90 _n >>= 16;
91 _v += 16;
92 }
93 if ((_n & 0x00000000000000FFULL) == 0) {
94 _n >>= 8;
95 _v += 8;
96 }
97 if ((_n & 0x000000000000000FULL) == 0) {
98 _n >>= 4;
99 _v += 4;
100 }
101 if ((_n & 0x0000000000000003ULL) == 0) {
102 _n >>= 2;
103 _v += 2;
104 }
105 if ((_n & 0x0000000000000001ULL) == 0) {
106 //_n >>= 1;
107 _v += 1;
108 }
109 return _v;
110 }
111 #endif
112
113 /*
114 * Find Last Set functions
115 */
116 #ifndef fls32
117 static __inline int __unused
fls32(uint32_t _n)118 fls32(uint32_t _n)
119 {
120 int _v;
121
122 if (!_n)
123 return 0;
124
125 _v = 32;
126 if ((_n & 0xFFFF0000U) == 0) {
127 _n <<= 16;
128 _v -= 16;
129 }
130 if ((_n & 0xFF000000U) == 0) {
131 _n <<= 8;
132 _v -= 8;
133 }
134 if ((_n & 0xF0000000U) == 0) {
135 _n <<= 4;
136 _v -= 4;
137 }
138 if ((_n & 0xC0000000U) == 0) {
139 _n <<= 2;
140 _v -= 2;
141 }
142 if ((_n & 0x80000000U) == 0) {
143 //_n <<= 1;
144 _v -= 1;
145 }
146 return _v;
147 }
148 #endif
149
150 #ifndef fls64
151 static int __unused
fls64(uint64_t _n)152 fls64(uint64_t _n)
153 {
154 int _v;
155
156 if (!_n)
157 return 0;
158
159 _v = 64;
160 if ((_n & 0xFFFFFFFF00000000ULL) == 0) {
161 _n <<= 32;
162 _v -= 32;
163 }
164 if ((_n & 0xFFFF000000000000ULL) == 0) {
165 _n <<= 16;
166 _v -= 16;
167 }
168 if ((_n & 0xFF00000000000000ULL) == 0) {
169 _n <<= 8;
170 _v -= 8;
171 }
172 if ((_n & 0xF000000000000000ULL) == 0) {
173 _n <<= 4;
174 _v -= 4;
175 }
176 if ((_n & 0xC000000000000000ULL) == 0) {
177 _n <<= 2;
178 _v -= 2;
179 }
180 if ((_n & 0x8000000000000000ULL) == 0) {
181 //_n <<= 1;
182 _v -= 1;
183 }
184 return _v;
185 }
186 #endif
187
188 #endif /* COMPAT_BITOPS_H_ */
189