1 /* $NetBSD: bitops.h,v 1.15 2021/09/12 15:22:05 rillig 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 #ifndef _SYS_BITOPS_H_
32 #define _SYS_BITOPS_H_
33
34 #include <sys/stdint.h>
35
36 /*
37 * Find First Set functions
38 */
39 #ifndef ffs32
40 static __inline int __unused
ffs32(uint32_t _n)41 ffs32(uint32_t _n)
42 {
43 int _v;
44
45 if (!_n)
46 return 0;
47
48 _v = 1;
49 if ((_n & 0x0000FFFFU) == 0) {
50 _n >>= 16;
51 _v += 16;
52 }
53 if ((_n & 0x000000FFU) == 0) {
54 _n >>= 8;
55 _v += 8;
56 }
57 if ((_n & 0x0000000FU) == 0) {
58 _n >>= 4;
59 _v += 4;
60 }
61 if ((_n & 0x00000003U) == 0) {
62 _n >>= 2;
63 _v += 2;
64 }
65 if ((_n & 0x00000001U) == 0) {
66 _n >>= 1;
67 _v += 1;
68 }
69 return _v;
70 }
71 #endif
72
73 #ifndef ffs64
74 static __inline int __unused
ffs64(uint64_t _n)75 ffs64(uint64_t _n)
76 {
77 int _v;
78
79 if (!_n)
80 return 0;
81
82 _v = 1;
83 if ((_n & 0x00000000FFFFFFFFULL) == 0) {
84 _n >>= 32;
85 _v += 32;
86 }
87 if ((_n & 0x000000000000FFFFULL) == 0) {
88 _n >>= 16;
89 _v += 16;
90 }
91 if ((_n & 0x00000000000000FFULL) == 0) {
92 _n >>= 8;
93 _v += 8;
94 }
95 if ((_n & 0x000000000000000FULL) == 0) {
96 _n >>= 4;
97 _v += 4;
98 }
99 if ((_n & 0x0000000000000003ULL) == 0) {
100 _n >>= 2;
101 _v += 2;
102 }
103 if ((_n & 0x0000000000000001ULL) == 0) {
104 _n >>= 1;
105 _v += 1;
106 }
107 return _v;
108 }
109 #endif
110
111 /*
112 * Find Last Set functions
113 */
114 #ifndef fls32
115 static __inline int __unused
fls32(uint32_t _n)116 fls32(uint32_t _n)
117 {
118 int _v;
119
120 if (!_n)
121 return 0;
122
123 _v = 32;
124 if ((_n & 0xFFFF0000U) == 0) {
125 _n <<= 16;
126 _v -= 16;
127 }
128 if ((_n & 0xFF000000U) == 0) {
129 _n <<= 8;
130 _v -= 8;
131 }
132 if ((_n & 0xF0000000U) == 0) {
133 _n <<= 4;
134 _v -= 4;
135 }
136 if ((_n & 0xC0000000U) == 0) {
137 _n <<= 2;
138 _v -= 2;
139 }
140 if ((_n & 0x80000000U) == 0) {
141 _n <<= 1;
142 _v -= 1;
143 }
144 return _v;
145 }
146 #endif
147
148 #ifndef fls64
149 static __inline int __unused
fls64(uint64_t _n)150 fls64(uint64_t _n)
151 {
152 int _v;
153
154 if (!_n)
155 return 0;
156
157 _v = 64;
158 if ((_n & 0xFFFFFFFF00000000ULL) == 0) {
159 _n <<= 32;
160 _v -= 32;
161 }
162 if ((_n & 0xFFFF000000000000ULL) == 0) {
163 _n <<= 16;
164 _v -= 16;
165 }
166 if ((_n & 0xFF00000000000000ULL) == 0) {
167 _n <<= 8;
168 _v -= 8;
169 }
170 if ((_n & 0xF000000000000000ULL) == 0) {
171 _n <<= 4;
172 _v -= 4;
173 }
174 if ((_n & 0xC000000000000000ULL) == 0) {
175 _n <<= 2;
176 _v -= 2;
177 }
178 if ((_n & 0x8000000000000000ULL) == 0) {
179 _n <<= 1;
180 _v -= 1;
181 }
182 return _v;
183 }
184 #endif
185
186 /*
187 * Integer logarithm, returns -1 on error. Inspired by the linux
188 * version written by David Howells.
189 */
190 #define _ilog2_helper(_n, _x) ((_n) & (1ULL << (_x))) ? _x :
191 #define _ilog2_const(_n) ( \
192 _ilog2_helper(_n, 63) \
193 _ilog2_helper(_n, 62) \
194 _ilog2_helper(_n, 61) \
195 _ilog2_helper(_n, 60) \
196 _ilog2_helper(_n, 59) \
197 _ilog2_helper(_n, 58) \
198 _ilog2_helper(_n, 57) \
199 _ilog2_helper(_n, 56) \
200 _ilog2_helper(_n, 55) \
201 _ilog2_helper(_n, 54) \
202 _ilog2_helper(_n, 53) \
203 _ilog2_helper(_n, 52) \
204 _ilog2_helper(_n, 51) \
205 _ilog2_helper(_n, 50) \
206 _ilog2_helper(_n, 49) \
207 _ilog2_helper(_n, 48) \
208 _ilog2_helper(_n, 47) \
209 _ilog2_helper(_n, 46) \
210 _ilog2_helper(_n, 45) \
211 _ilog2_helper(_n, 44) \
212 _ilog2_helper(_n, 43) \
213 _ilog2_helper(_n, 42) \
214 _ilog2_helper(_n, 41) \
215 _ilog2_helper(_n, 40) \
216 _ilog2_helper(_n, 39) \
217 _ilog2_helper(_n, 38) \
218 _ilog2_helper(_n, 37) \
219 _ilog2_helper(_n, 36) \
220 _ilog2_helper(_n, 35) \
221 _ilog2_helper(_n, 34) \
222 _ilog2_helper(_n, 33) \
223 _ilog2_helper(_n, 32) \
224 _ilog2_helper(_n, 31) \
225 _ilog2_helper(_n, 30) \
226 _ilog2_helper(_n, 29) \
227 _ilog2_helper(_n, 28) \
228 _ilog2_helper(_n, 27) \
229 _ilog2_helper(_n, 26) \
230 _ilog2_helper(_n, 25) \
231 _ilog2_helper(_n, 24) \
232 _ilog2_helper(_n, 23) \
233 _ilog2_helper(_n, 22) \
234 _ilog2_helper(_n, 21) \
235 _ilog2_helper(_n, 20) \
236 _ilog2_helper(_n, 19) \
237 _ilog2_helper(_n, 18) \
238 _ilog2_helper(_n, 17) \
239 _ilog2_helper(_n, 16) \
240 _ilog2_helper(_n, 15) \
241 _ilog2_helper(_n, 14) \
242 _ilog2_helper(_n, 13) \
243 _ilog2_helper(_n, 12) \
244 _ilog2_helper(_n, 11) \
245 _ilog2_helper(_n, 10) \
246 _ilog2_helper(_n, 9) \
247 _ilog2_helper(_n, 8) \
248 _ilog2_helper(_n, 7) \
249 _ilog2_helper(_n, 6) \
250 _ilog2_helper(_n, 5) \
251 _ilog2_helper(_n, 4) \
252 _ilog2_helper(_n, 3) \
253 _ilog2_helper(_n, 2) \
254 _ilog2_helper(_n, 1) \
255 _ilog2_helper(_n, 0) \
256 -1)
257
258 #define ilog2(_n) \
259 ( \
260 __builtin_constant_p(_n) ? _ilog2_const(_n) : \
261 ((sizeof(_n) > 4 ? fls64(_n) : fls32(_n)) - 1) \
262 )
263
264 static __inline void
fast_divide32_prepare(uint32_t _div,uint32_t * __restrict _m,uint8_t * __restrict _s1,uint8_t * __restrict _s2)265 fast_divide32_prepare(uint32_t _div, uint32_t * __restrict _m,
266 uint8_t *__restrict _s1, uint8_t *__restrict _s2)
267 {
268 uint64_t _mt;
269 int _l;
270
271 _l = fls32(_div - 1);
272 _mt = (uint64_t)(0x100000000ULL * ((1ULL << _l) - _div));
273 *_m = (uint32_t)(_mt / _div + 1);
274 *_s1 = (_l > 1) ? 1U : (uint8_t)_l;
275 *_s2 = (_l == 0) ? 0 : (uint8_t)(_l - 1);
276 }
277
278 /* ARGSUSED */
279 static __inline uint32_t
fast_divide32(uint32_t _v,uint32_t _div __unused,uint32_t _m,uint8_t _s1,uint8_t _s2)280 fast_divide32(uint32_t _v, uint32_t _div __unused, uint32_t _m, uint8_t _s1,
281 uint8_t _s2)
282 {
283 uint32_t _t;
284
285 _t = (uint32_t)(((uint64_t)_v * _m) >> 32);
286 return (_t + ((_v - _t) >> _s1)) >> _s2;
287 }
288
289 static __inline uint32_t
fast_remainder32(uint32_t _v,uint32_t _div,uint32_t _m,uint8_t _s1,uint8_t _s2)290 fast_remainder32(uint32_t _v, uint32_t _div, uint32_t _m, uint8_t _s1,
291 uint8_t _s2)
292 {
293
294 return _v - _div * fast_divide32(_v, _div, _m, _s1, _s2);
295 }
296
297 #define __BITMAP_TYPE(__s, __t, __n) struct __s { \
298 __t _b[__BITMAP_SIZE(__t, __n)]; \
299 }
300
301 #define __BITMAP_BITS(__t) (sizeof(__t) * NBBY)
302 #define __BITMAP_SHIFT(__t) (ilog2(__BITMAP_BITS(__t)))
303 #define __BITMAP_MASK(__t) (__BITMAP_BITS(__t) - 1)
304 #define __BITMAP_SIZE(__t, __n) \
305 (((__n) + (__BITMAP_BITS(__t) - 1)) / __BITMAP_BITS(__t))
306 #define __BITMAP_BIT(__n, __v) \
307 ((__typeof__((__v)->_b[0]))1 << ((__n) & __BITMAP_MASK(*(__v)->_b)))
308 #define __BITMAP_WORD(__n, __v) \
309 ((__n) >> __BITMAP_SHIFT(*(__v)->_b))
310
311 #define __BITMAP_SET(__n, __v) \
312 ((__v)->_b[__BITMAP_WORD(__n, __v)] |= __BITMAP_BIT(__n, __v))
313 #define __BITMAP_CLR(__n, __v) \
314 ((__v)->_b[__BITMAP_WORD(__n, __v)] &= ~__BITMAP_BIT(__n, __v))
315 #define __BITMAP_ISSET(__n, __v) \
316 ((__v)->_b[__BITMAP_WORD(__n, __v)] & __BITMAP_BIT(__n, __v))
317
318 #if __GNUC_PREREQ__(2, 95)
319 #define __BITMAP_ZERO(__v) \
320 (void)__builtin_memset((__v), 0, sizeof(*__v))
321 #else
322 #define __BITMAP_ZERO(__v) do { \
323 size_t __i; \
324 for (__i = 0; __i < __arraycount((__v)->_b); __i++) \
325 (__v)->_b[__i] = 0; \
326 } while (/* CONSTCOND */ 0)
327 #endif /* GCC 2.95 */
328
329 #endif /* _SYS_BITOPS_H_ */
330