| 1 | /* $NetBSD: bitops.h,v 1.11 2015/10/13 00:42:59 riastradh Exp $ */ |
| 2 | |
| 3 | /*- |
| 4 | * Copyright (c) 2013 The NetBSD Foundation, Inc. |
| 5 | * All rights reserved. |
| 6 | * |
| 7 | * This code is derived from software contributed to The NetBSD Foundation |
| 8 | * by Taylor R. Campbell. |
| 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 _LINUX_BITOPS_H_ |
| 33 | #define _LINUX_BITOPS_H_ |
| 34 | |
| 35 | #include <sys/cdefs.h> |
| 36 | #include <sys/types.h> |
| 37 | #include <sys/param.h> |
| 38 | #include <sys/atomic.h> |
| 39 | #include <sys/bitops.h> |
| 40 | |
| 41 | #include <machine/limits.h> |
| 42 | |
| 43 | #include <lib/libkern/libkern.h> |
| 44 | |
| 45 | /* |
| 46 | * Linux __ffs/__ffs64 is zero-based; zero input is undefined. Our |
| 47 | * ffs/ffs64 is one-based; zero input yields zero. |
| 48 | */ |
| 49 | static inline unsigned long |
| 50 | __ffs(unsigned long x) |
| 51 | { |
| 52 | |
| 53 | KASSERT(x != 0); |
| 54 | return ffs64(x) - 1; |
| 55 | } |
| 56 | |
| 57 | static inline unsigned long |
| 58 | __ffs64(uint64_t x) |
| 59 | { |
| 60 | |
| 61 | KASSERT(x != 0); |
| 62 | return ffs64(x) - 1; |
| 63 | } |
| 64 | |
| 65 | static inline unsigned int |
| 66 | hweight16(uint16_t n) |
| 67 | { |
| 68 | return popcount32(n); |
| 69 | } |
| 70 | |
| 71 | static inline unsigned int |
| 72 | hweight32(uint16_t n) |
| 73 | { |
| 74 | return popcount32(n); |
| 75 | } |
| 76 | |
| 77 | /* |
| 78 | * XXX Don't define BITS_PER_LONG as sizeof(unsigned long)*CHAR_BIT |
| 79 | * because that won't work in preprocessor conditionals, where it often |
| 80 | * turns up. |
| 81 | */ |
| 82 | |
| 83 | #define BITS_TO_LONGS(n) \ |
| 84 | roundup2((n), (sizeof(unsigned long) * CHAR_BIT)) |
| 85 | |
| 86 | #define BIT(n) ((uintmax_t)1 << (n)) |
| 87 | |
| 88 | static inline int |
| 89 | test_bit(unsigned int n, const volatile unsigned long *p) |
| 90 | { |
| 91 | const unsigned units = (sizeof(unsigned long) * CHAR_BIT); |
| 92 | |
| 93 | return ((p[n / units] & (1UL << (n % units))) != 0); |
| 94 | } |
| 95 | |
| 96 | static inline void |
| 97 | __set_bit(unsigned int n, volatile unsigned long *p) |
| 98 | { |
| 99 | const unsigned units = (sizeof(unsigned long) * CHAR_BIT); |
| 100 | |
| 101 | p[n / units] |= (1UL << (n % units)); |
| 102 | } |
| 103 | |
| 104 | static inline void |
| 105 | __clear_bit(unsigned int n, volatile unsigned long *p) |
| 106 | { |
| 107 | const unsigned units = (sizeof(unsigned long) * CHAR_BIT); |
| 108 | |
| 109 | p[n / units] &= ~(1UL << (n % units)); |
| 110 | } |
| 111 | |
| 112 | static inline void |
| 113 | __change_bit(unsigned int n, volatile unsigned long *p) |
| 114 | { |
| 115 | const unsigned units = (sizeof(unsigned long) * CHAR_BIT); |
| 116 | |
| 117 | p[n / units] ^= (1UL << (n % units)); |
| 118 | } |
| 119 | |
| 120 | static inline unsigned long |
| 121 | __test_and_set_bit(unsigned int bit, volatile unsigned long *ptr) |
| 122 | { |
| 123 | const unsigned int units = (sizeof(*ptr) * CHAR_BIT); |
| 124 | volatile unsigned long *const p = &ptr[bit / units]; |
| 125 | const unsigned long mask = (1UL << (bit % units)); |
| 126 | unsigned long v; |
| 127 | |
| 128 | v = *p; |
| 129 | *p |= mask; |
| 130 | |
| 131 | return ((v & mask) != 0); |
| 132 | } |
| 133 | |
| 134 | static inline unsigned long |
| 135 | __test_and_clear_bit(unsigned int bit, volatile unsigned long *ptr) |
| 136 | { |
| 137 | const unsigned int units = (sizeof(*ptr) * CHAR_BIT); |
| 138 | volatile unsigned long *const p = &ptr[bit / units]; |
| 139 | const unsigned long mask = (1UL << (bit % units)); |
| 140 | unsigned long v; |
| 141 | |
| 142 | v = *p; |
| 143 | *p &= ~mask; |
| 144 | |
| 145 | return ((v & mask) != 0); |
| 146 | } |
| 147 | |
| 148 | static inline unsigned long |
| 149 | __test_and_change_bit(unsigned int bit, volatile unsigned long *ptr) |
| 150 | { |
| 151 | const unsigned int units = (sizeof(*ptr) * CHAR_BIT); |
| 152 | volatile unsigned long *const p = &ptr[bit / units]; |
| 153 | const unsigned long mask = (1UL << (bit % units)); |
| 154 | unsigned long v; |
| 155 | |
| 156 | v = *p; |
| 157 | *p ^= mask; |
| 158 | |
| 159 | return ((v & mask) != 0); |
| 160 | } |
| 161 | |
| 162 | static inline unsigned long |
| 163 | find_first_zero_bit(const unsigned long *ptr, unsigned long nbits) |
| 164 | { |
| 165 | const size_t bpl = (CHAR_BIT * sizeof(*ptr)); |
| 166 | const unsigned long *p; |
| 167 | unsigned long result = 0; |
| 168 | |
| 169 | for (p = ptr; bpl < nbits; nbits -= bpl, p++, result += bpl) { |
| 170 | if (~*p) |
| 171 | break; |
| 172 | } |
| 173 | |
| 174 | result += ffs(~*p | (~0UL << MIN(nbits, bpl))); |
| 175 | return result; |
| 176 | } |
| 177 | |
| 178 | static inline unsigned |
| 179 | hweight8(unsigned w) |
| 180 | { |
| 181 | |
| 182 | return popcount(w & 0xff); |
| 183 | } |
| 184 | |
| 185 | #endif /* _LINUX_BITOPS_H_ */ |
| 186 | |