| /* |
| * Copyright (c) 2010 Mans Rullgard <mans@mansr.com> |
| * |
| * This file is part of FFmpeg. |
| * |
| * FFmpeg is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU Lesser General Public |
| * License as published by the Free Software Foundation; either |
| * version 2.1 of the License, or (at your option) any later version. |
| * |
| * FFmpeg is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * Lesser General Public License for more details. |
| * |
| * You should have received a copy of the GNU Lesser General Public |
| * License along with FFmpeg; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| */ |
| |
| #ifndef AVUTIL_INTMATH_H |
| #define AVUTIL_INTMATH_H |
| |
| #include <stdint.h> |
| |
| #include "config.h" |
| #include "attributes.h" |
| |
| #if ARCH_ARM |
| # include "arm/intmath.h" |
| #endif |
| #if ARCH_X86 |
| # include "x86/intmath.h" |
| #endif |
| |
| #if HAVE_FAST_CLZ |
| #if AV_GCC_VERSION_AT_LEAST(3,4) |
| #ifndef ff_log2 |
| # define ff_log2(x) (31 - __builtin_clz((x)|1)) |
| # ifndef ff_log2_16bit |
| # define ff_log2_16bit av_log2 |
| # endif |
| #endif /* ff_log2 */ |
| #endif /* AV_GCC_VERSION_AT_LEAST(3,4) */ |
| #endif |
| |
| extern const uint8_t ff_log2_tab[256]; |
| |
| #ifndef ff_log2 |
| #define ff_log2 ff_log2_c |
| static av_always_inline av_const int ff_log2_c(unsigned int v) |
| { |
| int n = 0; |
| if (v & 0xffff0000) { |
| v >>= 16; |
| n += 16; |
| } |
| if (v & 0xff00) { |
| v >>= 8; |
| n += 8; |
| } |
| n += ff_log2_tab[v]; |
| |
| return n; |
| } |
| #endif |
| |
| #ifndef ff_log2_16bit |
| #define ff_log2_16bit ff_log2_16bit_c |
| static av_always_inline av_const int ff_log2_16bit_c(unsigned int v) |
| { |
| int n = 0; |
| if (v & 0xff00) { |
| v >>= 8; |
| n += 8; |
| } |
| n += ff_log2_tab[v]; |
| |
| return n; |
| } |
| #endif |
| |
| #define av_log2 ff_log2 |
| #define av_log2_16bit ff_log2_16bit |
| |
| /** |
| * @addtogroup lavu_math |
| * @{ |
| */ |
| |
| #if HAVE_FAST_CLZ |
| #if AV_GCC_VERSION_AT_LEAST(3,4) |
| #ifndef ff_ctz |
| #define ff_ctz(v) __builtin_ctz(v) |
| #endif |
| #ifndef ff_ctzll |
| #define ff_ctzll(v) __builtin_ctzll(v) |
| #endif |
| #ifndef ff_clz |
| #define ff_clz(v) __builtin_clz(v) |
| #endif |
| #endif |
| #endif |
| |
| #ifndef ff_ctz |
| #define ff_ctz ff_ctz_c |
| /** |
| * Trailing zero bit count. |
| * |
| * @param v input value. If v is 0, the result is undefined. |
| * @return the number of trailing 0-bits |
| */ |
| /* We use the De-Bruijn method outlined in: |
| * http://supertech.csail.mit.edu/papers/debruijn.pdf. */ |
| static av_always_inline av_const int ff_ctz_c(int v) |
| { |
| static const uint8_t debruijn_ctz32[32] = { |
| 0, 1, 28, 2, 29, 14, 24, 3, 30, 22, 20, 15, 25, 17, 4, 8, |
| 31, 27, 13, 23, 21, 19, 16, 7, 26, 12, 18, 6, 11, 5, 10, 9 |
| }; |
| return debruijn_ctz32[(uint32_t)((v & -v) * 0x077CB531U) >> 27]; |
| } |
| #endif |
| |
| #ifndef ff_ctzll |
| #define ff_ctzll ff_ctzll_c |
| /* We use the De-Bruijn method outlined in: |
| * http://supertech.csail.mit.edu/papers/debruijn.pdf. */ |
| static av_always_inline av_const int ff_ctzll_c(long long v) |
| { |
| static const uint8_t debruijn_ctz64[64] = { |
| 0, 1, 2, 53, 3, 7, 54, 27, 4, 38, 41, 8, 34, 55, 48, 28, |
| 62, 5, 39, 46, 44, 42, 22, 9, 24, 35, 59, 56, 49, 18, 29, 11, |
| 63, 52, 6, 26, 37, 40, 33, 47, 61, 45, 43, 21, 23, 58, 17, 10, |
| 51, 25, 36, 32, 60, 20, 57, 16, 50, 31, 19, 15, 30, 14, 13, 12 |
| }; |
| return debruijn_ctz64[(uint64_t)((v & -v) * 0x022FDD63CC95386DU) >> 58]; |
| } |
| #endif |
| |
| #ifndef ff_clz |
| #define ff_clz ff_clz_c |
| static av_always_inline av_const unsigned ff_clz_c(unsigned x) |
| { |
| unsigned i = sizeof(x) * 8; |
| |
| while (x) { |
| x >>= 1; |
| i--; |
| } |
| |
| return i; |
| } |
| #endif |
| |
| #if AV_GCC_VERSION_AT_LEAST(3,4) |
| #ifndef av_parity |
| #define av_parity __builtin_parity |
| #endif |
| #endif |
| |
| /** |
| * @} |
| */ |
| #endif /* AVUTIL_INTMATH_H */ |