blob: 9573109e9d1b910496cc280815883a011e96feb2
| 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 | #if ARCH_X86 |
| 33 | # include "x86/intmath.h" |
| 34 | #endif |
| 35 | |
| 36 | #if HAVE_FAST_CLZ |
| 37 | #if AV_GCC_VERSION_AT_LEAST(3,4) |
| 38 | #ifndef ff_log2 |
| 39 | # define ff_log2(x) (31 - __builtin_clz((x)|1)) |
| 40 | # ifndef ff_log2_16bit |
| 41 | # define ff_log2_16bit av_log2 |
| 42 | # endif |
| 43 | #endif /* ff_log2 */ |
| 44 | #endif /* AV_GCC_VERSION_AT_LEAST(3,4) */ |
| 45 | #endif |
| 46 | |
| 47 | extern const uint8_t ff_log2_tab[256]; |
| 48 | |
| 49 | #ifndef ff_log2 |
| 50 | #define ff_log2 ff_log2_c |
| 51 | static av_always_inline av_const int ff_log2_c(unsigned int v) |
| 52 | { |
| 53 | int n = 0; |
| 54 | if (v & 0xffff0000) { |
| 55 | v >>= 16; |
| 56 | n += 16; |
| 57 | } |
| 58 | if (v & 0xff00) { |
| 59 | v >>= 8; |
| 60 | n += 8; |
| 61 | } |
| 62 | n += ff_log2_tab[v]; |
| 63 | |
| 64 | return n; |
| 65 | } |
| 66 | #endif |
| 67 | |
| 68 | #ifndef ff_log2_16bit |
| 69 | #define ff_log2_16bit ff_log2_16bit_c |
| 70 | static av_always_inline av_const int ff_log2_16bit_c(unsigned int v) |
| 71 | { |
| 72 | int n = 0; |
| 73 | if (v & 0xff00) { |
| 74 | v >>= 8; |
| 75 | n += 8; |
| 76 | } |
| 77 | n += ff_log2_tab[v]; |
| 78 | |
| 79 | return n; |
| 80 | } |
| 81 | #endif |
| 82 | |
| 83 | #define av_log2 ff_log2 |
| 84 | #define av_log2_16bit ff_log2_16bit |
| 85 | |
| 86 | /** |
| 87 | * @addtogroup lavu_math |
| 88 | * @{ |
| 89 | */ |
| 90 | |
| 91 | #if HAVE_FAST_CLZ |
| 92 | #if AV_GCC_VERSION_AT_LEAST(3,4) |
| 93 | #ifndef ff_ctz |
| 94 | #define ff_ctz(v) __builtin_ctz(v) |
| 95 | #endif |
| 96 | #ifndef ff_ctzll |
| 97 | #define ff_ctzll(v) __builtin_ctzll(v) |
| 98 | #endif |
| 99 | #ifndef ff_clz |
| 100 | #define ff_clz(v) __builtin_clz(v) |
| 101 | #endif |
| 102 | #endif |
| 103 | #endif |
| 104 | |
| 105 | #ifndef ff_ctz |
| 106 | #define ff_ctz ff_ctz_c |
| 107 | /** |
| 108 | * Trailing zero bit count. |
| 109 | * |
| 110 | * @param v input value. If v is 0, the result is undefined. |
| 111 | * @return the number of trailing 0-bits |
| 112 | */ |
| 113 | /* We use the De-Bruijn method outlined in: |
| 114 | * http://supertech.csail.mit.edu/papers/debruijn.pdf. */ |
| 115 | static av_always_inline av_const int ff_ctz_c(int v) |
| 116 | { |
| 117 | static const uint8_t debruijn_ctz32[32] = { |
| 118 | 0, 1, 28, 2, 29, 14, 24, 3, 30, 22, 20, 15, 25, 17, 4, 8, |
| 119 | 31, 27, 13, 23, 21, 19, 16, 7, 26, 12, 18, 6, 11, 5, 10, 9 |
| 120 | }; |
| 121 | return debruijn_ctz32[(uint32_t)((v & -v) * 0x077CB531U) >> 27]; |
| 122 | } |
| 123 | #endif |
| 124 | |
| 125 | #ifndef ff_ctzll |
| 126 | #define ff_ctzll ff_ctzll_c |
| 127 | /* We use the De-Bruijn method outlined in: |
| 128 | * http://supertech.csail.mit.edu/papers/debruijn.pdf. */ |
| 129 | static av_always_inline av_const int ff_ctzll_c(long long v) |
| 130 | { |
| 131 | static const uint8_t debruijn_ctz64[64] = { |
| 132 | 0, 1, 2, 53, 3, 7, 54, 27, 4, 38, 41, 8, 34, 55, 48, 28, |
| 133 | 62, 5, 39, 46, 44, 42, 22, 9, 24, 35, 59, 56, 49, 18, 29, 11, |
| 134 | 63, 52, 6, 26, 37, 40, 33, 47, 61, 45, 43, 21, 23, 58, 17, 10, |
| 135 | 51, 25, 36, 32, 60, 20, 57, 16, 50, 31, 19, 15, 30, 14, 13, 12 |
| 136 | }; |
| 137 | return debruijn_ctz64[(uint64_t)((v & -v) * 0x022FDD63CC95386DU) >> 58]; |
| 138 | } |
| 139 | #endif |
| 140 | |
| 141 | #ifndef ff_clz |
| 142 | #define ff_clz ff_clz_c |
| 143 | static av_always_inline av_const unsigned ff_clz_c(unsigned x) |
| 144 | { |
| 145 | unsigned i = sizeof(x) * 8; |
| 146 | |
| 147 | while (x) { |
| 148 | x >>= 1; |
| 149 | i--; |
| 150 | } |
| 151 | |
| 152 | return i; |
| 153 | } |
| 154 | #endif |
| 155 | |
| 156 | #if AV_GCC_VERSION_AT_LEAST(3,4) |
| 157 | #ifndef av_parity |
| 158 | #define av_parity __builtin_parity |
| 159 | #endif |
| 160 | #endif |
| 161 | |
| 162 | /** |
| 163 | * @} |
| 164 | */ |
| 165 | #endif /* AVUTIL_INTMATH_H */ |
| 166 |