| 1 | /* |
| 2 | * Copyright (c) 2010 Mans Rullgard <mans@mansr.com> |
| 3 | * |
| 4 | * This file is part of FFmpeg. |
| 5 | * |
| 6 | * FFmpeg is free software; you can redistribute it and/or |
| 7 | * modify it under the terms of the GNU Lesser General Public |
| 8 | * License as published by the Free Software Foundation; either |
| 9 | * version 2.1 of the License, or (at your option) any later version. |
| 10 | * |
| 11 | * FFmpeg is distributed in the hope that it will be useful, |
| 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 14 | * Lesser General Public License for more details. |
| 15 | * |
| 16 | * You should have received a copy of the GNU Lesser General Public |
| 17 | * License along with FFmpeg; if not, write to the Free Software |
| 18 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 19 | */ |
| 20 | |
| 21 | #ifndef AVUTIL_INTMATH_H |
| 22 | #define AVUTIL_INTMATH_H |
| 23 | |
| 24 | #include <stdint.h> |
| 25 | |
| 26 | #include "config.h" |
| 27 | #include "attributes.h" |
| 28 | |
| 29 | #if ARCH_ARM |
| 30 | # include "arm/intmath.h" |
| 31 | #endif |
| 32 | |
| 33 | /** |
| 34 | * @addtogroup lavu_internal |
| 35 | * @{ |
| 36 | */ |
| 37 | |
| 38 | #if HAVE_FAST_CLZ |
| 39 | #if AV_GCC_VERSION_AT_LEAST(3,4) |
| 40 | #ifndef ff_log2 |
| 41 | # define ff_log2(x) (31 - __builtin_clz((x)|1)) |
| 42 | # ifndef ff_log2_16bit |
| 43 | # define ff_log2_16bit av_log2 |
| 44 | # endif |
| 45 | #endif /* ff_log2 */ |
| 46 | #elif defined( __INTEL_COMPILER ) |
| 47 | #ifndef ff_log2 |
| 48 | # define ff_log2(x) (_bit_scan_reverse(x|1)) |
| 49 | # ifndef ff_log2_16bit |
| 50 | # define ff_log2_16bit av_log2 |
| 51 | # endif |
| 52 | #endif /* ff_log2 */ |
| 53 | #endif |
| 54 | #endif /* AV_GCC_VERSION_AT_LEAST(3,4) */ |
| 55 | |
| 56 | extern const uint8_t ff_log2_tab[256]; |
| 57 | |
| 58 | #ifndef ff_log2 |
| 59 | #define ff_log2 ff_log2_c |
| 60 | #if !defined( _MSC_VER ) |
| 61 | static av_always_inline av_const int ff_log2_c(unsigned int v) |
| 62 | { |
| 63 | int n = 0; |
| 64 | if (v & 0xffff0000) { |
| 65 | v >>= 16; |
| 66 | n += 16; |
| 67 | } |
| 68 | if (v & 0xff00) { |
| 69 | v >>= 8; |
| 70 | n += 8; |
| 71 | } |
| 72 | n += ff_log2_tab[v]; |
| 73 | |
| 74 | return n; |
| 75 | } |
| 76 | #else |
| 77 | static av_always_inline av_const int ff_log2_c(unsigned int v) |
| 78 | { |
| 79 | unsigned long n; |
| 80 | _BitScanReverse(&n, v|1); |
| 81 | return n; |
| 82 | } |
| 83 | #define ff_log2_16bit av_log2 |
| 84 | #endif |
| 85 | #endif |
| 86 | |
| 87 | #ifndef ff_log2_16bit |
| 88 | #define ff_log2_16bit ff_log2_16bit_c |
| 89 | static av_always_inline av_const int ff_log2_16bit_c(unsigned int v) |
| 90 | { |
| 91 | int n = 0; |
| 92 | if (v & 0xff00) { |
| 93 | v >>= 8; |
| 94 | n += 8; |
| 95 | } |
| 96 | n += ff_log2_tab[v]; |
| 97 | |
| 98 | return n; |
| 99 | } |
| 100 | #endif |
| 101 | |
| 102 | #define av_log2 ff_log2 |
| 103 | #define av_log2_16bit ff_log2_16bit |
| 104 | |
| 105 | /** |
| 106 | * @} |
| 107 | */ |
| 108 | |
| 109 | /** |
| 110 | * @addtogroup lavu_math |
| 111 | * @{ |
| 112 | */ |
| 113 | |
| 114 | #if HAVE_FAST_CLZ |
| 115 | #if AV_GCC_VERSION_AT_LEAST(3,4) |
| 116 | #ifndef ff_ctz |
| 117 | #define ff_ctz(v) __builtin_ctz(v) |
| 118 | #endif |
| 119 | #elif defined( __INTEL_COMPILER ) |
| 120 | #ifndef ff_ctz |
| 121 | #define ff_ctz(v) _bit_scan_forward(v) |
| 122 | #endif |
| 123 | #endif |
| 124 | #endif |
| 125 | |
| 126 | #ifndef ff_ctz |
| 127 | #define ff_ctz ff_ctz_c |
| 128 | #if !defined( _MSC_VER ) |
| 129 | static av_always_inline av_const int ff_ctz_c(int v) |
| 130 | { |
| 131 | int c; |
| 132 | |
| 133 | if (v & 0x1) |
| 134 | return 0; |
| 135 | |
| 136 | c = 1; |
| 137 | if (!(v & 0xffff)) { |
| 138 | v >>= 16; |
| 139 | c += 16; |
| 140 | } |
| 141 | if (!(v & 0xff)) { |
| 142 | v >>= 8; |
| 143 | c += 8; |
| 144 | } |
| 145 | if (!(v & 0xf)) { |
| 146 | v >>= 4; |
| 147 | c += 4; |
| 148 | } |
| 149 | if (!(v & 0x3)) { |
| 150 | v >>= 2; |
| 151 | c += 2; |
| 152 | } |
| 153 | c -= v & 0x1; |
| 154 | |
| 155 | return c; |
| 156 | } |
| 157 | #else |
| 158 | static av_always_inline av_const int ff_ctz_c( int v ) |
| 159 | { |
| 160 | unsigned long c; |
| 161 | _BitScanForward(&c, v); |
| 162 | return c; |
| 163 | } |
| 164 | #endif |
| 165 | #endif |
| 166 | |
| 167 | /** |
| 168 | * Trailing zero bit count. |
| 169 | * |
| 170 | * @param v input value. If v is 0, the result is undefined. |
| 171 | * @return the number of trailing 0-bits |
| 172 | */ |
| 173 | int av_ctz(int v); |
| 174 | |
| 175 | /** |
| 176 | * @} |
| 177 | */ |
| 178 | #endif /* AVUTIL_INTMATH_H */ |