Ed Warnicke | cb9cada | 2015-12-08 15:45:58 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (c) 2015 Cisco and/or its affiliates. |
| 3 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 4 | * you may not use this file except in compliance with the License. |
| 5 | * You may obtain a copy of the License at: |
| 6 | * |
| 7 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 8 | * |
| 9 | * Unless required by applicable law or agreed to in writing, software |
| 10 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 11 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 12 | * See the License for the specific language governing permissions and |
| 13 | * limitations under the License. |
| 14 | */ |
| 15 | /* |
| 16 | Copyright (c) 2005 Eliot Dresselhaus |
| 17 | |
| 18 | Permission is hereby granted, free of charge, to any person obtaining |
| 19 | a copy of this software and associated documentation files (the |
| 20 | "Software"), to deal in the Software without restriction, including |
| 21 | without limitation the rights to use, copy, modify, merge, publish, |
| 22 | distribute, sublicense, and/or sell copies of the Software, and to |
| 23 | permit persons to whom the Software is furnished to do so, subject to |
| 24 | the following conditions: |
| 25 | |
| 26 | The above copyright notice and this permission notice shall be |
| 27 | included in all copies or substantial portions of the Software. |
| 28 | |
| 29 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, |
| 30 | EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF |
| 31 | MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND |
| 32 | NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE |
| 33 | LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION |
| 34 | OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION |
| 35 | WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. |
| 36 | */ |
| 37 | |
| 38 | #ifndef included_clib_bitops_h |
| 39 | #define included_clib_bitops_h |
| 40 | |
| 41 | #include <vppinfra/clib.h> |
| 42 | |
| 43 | /* Population count from Hacker's Delight. */ |
Dave Barach | c379999 | 2016-08-15 11:12:27 -0400 | [diff] [blame] | 44 | always_inline uword |
| 45 | count_set_bits (uword x) |
Ed Warnicke | cb9cada | 2015-12-08 15:45:58 -0700 | [diff] [blame] | 46 | { |
Damjan Marion | 23e310a | 2018-05-10 03:04:08 +0200 | [diff] [blame^] | 47 | #ifdef __POPCNT__ |
| 48 | #if uword_bits == 64 |
| 49 | return __builtin_popcountll (x); |
| 50 | #else |
| 51 | return __builtin_popcount (x); |
| 52 | #endif |
| 53 | #else |
Ed Warnicke | cb9cada | 2015-12-08 15:45:58 -0700 | [diff] [blame] | 54 | #if uword_bits == 64 |
| 55 | const uword c1 = 0x5555555555555555; |
| 56 | const uword c2 = 0x3333333333333333; |
| 57 | const uword c3 = 0x0f0f0f0f0f0f0f0f; |
| 58 | #else |
| 59 | const uword c1 = 0x55555555; |
| 60 | const uword c2 = 0x33333333; |
| 61 | const uword c3 = 0x0f0f0f0f; |
| 62 | #endif |
| 63 | |
| 64 | /* Sum 1 bit at a time. */ |
| 65 | x = x - ((x >> (uword) 1) & c1); |
| 66 | |
| 67 | /* 2 bits at a time. */ |
| 68 | x = (x & c2) + ((x >> (uword) 2) & c2); |
| 69 | |
| 70 | /* 4 bits at a time. */ |
| 71 | x = (x + (x >> (uword) 4)) & c3; |
| 72 | |
| 73 | /* 8, 16, 32 bits at a time. */ |
| 74 | x = x + (x >> (uword) 8); |
| 75 | x = x + (x >> (uword) 16); |
| 76 | #if uword_bits == 64 |
| 77 | x = x + (x >> (uword) 32); |
| 78 | #endif |
| 79 | |
Dave Barach | c379999 | 2016-08-15 11:12:27 -0400 | [diff] [blame] | 80 | return x & (2 * BITS (uword) - 1); |
Damjan Marion | 23e310a | 2018-05-10 03:04:08 +0200 | [diff] [blame^] | 81 | #endif |
Ed Warnicke | cb9cada | 2015-12-08 15:45:58 -0700 | [diff] [blame] | 82 | } |
| 83 | |
| 84 | /* Based on "Hacker's Delight" code from GLS. */ |
Dave Barach | c379999 | 2016-08-15 11:12:27 -0400 | [diff] [blame] | 85 | typedef struct |
| 86 | { |
Ed Warnicke | cb9cada | 2015-12-08 15:45:58 -0700 | [diff] [blame] | 87 | uword masks[1 + log2_uword_bits]; |
| 88 | } compress_main_t; |
| 89 | |
| 90 | always_inline void |
| 91 | compress_init (compress_main_t * cm, uword mask) |
| 92 | { |
| 93 | uword q, m, zm, n, i; |
| 94 | |
| 95 | m = ~mask; |
| 96 | zm = mask; |
| 97 | |
| 98 | cm->masks[0] = mask; |
| 99 | for (i = 0; i < log2_uword_bits; i++) |
| 100 | { |
| 101 | q = m; |
| 102 | m ^= m << 1; |
| 103 | m ^= m << 2; |
| 104 | m ^= m << 4; |
| 105 | m ^= m << 8; |
| 106 | m ^= m << 16; |
| 107 | #if uword_bits > 32 |
| 108 | m ^= m << (uword) 32; |
| 109 | #endif |
| 110 | cm->masks[1 + i] = n = (m << 1) & zm; |
| 111 | m = q & ~m; |
| 112 | q = zm & n; |
| 113 | zm = zm ^ q ^ (q >> (1 << i)); |
| 114 | } |
| 115 | } |
| 116 | |
| 117 | always_inline uword |
| 118 | compress_bits (compress_main_t * cm, uword x) |
| 119 | { |
| 120 | uword q, r; |
| 121 | |
| 122 | r = x & cm->masks[0]; |
Dave Barach | c379999 | 2016-08-15 11:12:27 -0400 | [diff] [blame] | 123 | q = r & cm->masks[1]; |
| 124 | r ^= q ^ (q >> 1); |
| 125 | q = r & cm->masks[2]; |
| 126 | r ^= q ^ (q >> 2); |
| 127 | q = r & cm->masks[3]; |
| 128 | r ^= q ^ (q >> 4); |
| 129 | q = r & cm->masks[4]; |
| 130 | r ^= q ^ (q >> 8); |
| 131 | q = r & cm->masks[5]; |
| 132 | r ^= q ^ (q >> 16); |
Ed Warnicke | cb9cada | 2015-12-08 15:45:58 -0700 | [diff] [blame] | 133 | #if uword_bits > 32 |
Dave Barach | c379999 | 2016-08-15 11:12:27 -0400 | [diff] [blame] | 134 | q = r & cm->masks[6]; |
| 135 | r ^= q ^ (q >> (uword) 32); |
Ed Warnicke | cb9cada | 2015-12-08 15:45:58 -0700 | [diff] [blame] | 136 | #endif |
| 137 | |
| 138 | return r; |
| 139 | } |
| 140 | |
| 141 | always_inline uword |
| 142 | rotate_left (uword x, uword i) |
Dave Barach | c379999 | 2016-08-15 11:12:27 -0400 | [diff] [blame] | 143 | { |
| 144 | return (x << i) | (x >> (BITS (i) - i)); |
| 145 | } |
Ed Warnicke | cb9cada | 2015-12-08 15:45:58 -0700 | [diff] [blame] | 146 | |
| 147 | always_inline uword |
| 148 | rotate_right (uword x, uword i) |
Dave Barach | c379999 | 2016-08-15 11:12:27 -0400 | [diff] [blame] | 149 | { |
| 150 | return (x >> i) | (x << (BITS (i) - i)); |
| 151 | } |
Ed Warnicke | cb9cada | 2015-12-08 15:45:58 -0700 | [diff] [blame] | 152 | |
| 153 | /* Returns snoob from Hacker's Delight. Next highest number |
| 154 | with same number of set bits. */ |
| 155 | always_inline uword |
| 156 | next_with_same_number_of_set_bits (uword x) |
| 157 | { |
| 158 | uword smallest, ripple, ones; |
| 159 | smallest = x & -x; |
| 160 | ripple = x + smallest; |
| 161 | ones = x ^ ripple; |
| 162 | ones = ones >> (2 + log2_first_set (x)); |
| 163 | return ripple | ones; |
| 164 | } |
| 165 | |
| 166 | #define foreach_set_bit(var,mask,body) \ |
| 167 | do { \ |
| 168 | uword _foreach_set_bit_m_##var = (mask); \ |
| 169 | uword _foreach_set_bit_f_##var; \ |
| 170 | while (_foreach_set_bit_m_##var != 0) \ |
| 171 | { \ |
| 172 | _foreach_set_bit_f_##var = first_set (_foreach_set_bit_m_##var); \ |
| 173 | _foreach_set_bit_m_##var ^= _foreach_set_bit_f_##var; \ |
| 174 | (var) = min_log2 (_foreach_set_bit_f_##var); \ |
| 175 | do { body; } while (0); \ |
| 176 | } \ |
| 177 | } while (0) |
| 178 | |
| 179 | #endif /* included_clib_bitops_h */ |
Dave Barach | c379999 | 2016-08-15 11:12:27 -0400 | [diff] [blame] | 180 | |
| 181 | /* |
| 182 | * fd.io coding-style-patch-verification: ON |
| 183 | * |
| 184 | * Local Variables: |
| 185 | * eval: (c-set-style "gnu") |
| 186 | * End: |
| 187 | */ |