mirror of
https://github.com/FFmpeg/FFmpeg.git
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Kacper Michajłow
794ffdc823
Every GCC able to pass the C11 configure check provides these builtins, attributes and pragmas. Public headers are left untouched since they must keep working with C99 compilers. Signed-off-by: Kacper Michajłow <kasper93@gmail.com>
165 lines
4.0 KiB
C
165 lines
4.0 KiB
C
/*
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* Copyright (c) 2010 Mans Rullgard <mans@mansr.com>
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#ifndef AVUTIL_INTMATH_H
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#define AVUTIL_INTMATH_H
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#include <stdint.h>
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#include "config.h"
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#include "attributes.h"
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#if ARCH_ARM
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# include "arm/intmath.h"
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#elif ARCH_RISCV
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# include "riscv/intmath.h"
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#elif ARCH_X86
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# include "x86/intmath.h"
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#endif
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#if HAVE_FAST_CLZ
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#if defined(__GNUC__) || AV_HAS_BUILTIN(__builtin_clz)
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#ifndef ff_log2
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# define ff_log2(x) (31 - __builtin_clz((x)|1))
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# ifndef ff_log2_16bit
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# define ff_log2_16bit av_log2
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# endif
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#endif /* ff_log2 */
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#endif /* defined(__GNUC__) || AV_HAS_BUILTIN(__builtin_clz) */
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#endif
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extern const uint8_t ff_log2_tab[256];
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#ifndef ff_log2
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#define ff_log2 ff_log2_c
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static av_always_inline av_const int ff_log2_c(unsigned int v)
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{
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int n = 0;
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if (v & 0xffff0000) {
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v >>= 16;
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n += 16;
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}
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if (v & 0xff00) {
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v >>= 8;
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n += 8;
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}
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n += ff_log2_tab[v];
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return n;
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}
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#endif
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#ifndef ff_log2_16bit
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#define ff_log2_16bit ff_log2_16bit_c
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static av_always_inline av_const int ff_log2_16bit_c(unsigned int v)
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{
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int n = 0;
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if (v & 0xff00) {
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v >>= 8;
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n += 8;
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}
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n += ff_log2_tab[v];
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return n;
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}
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#endif
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#define av_log2 ff_log2
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#define av_log2_16bit ff_log2_16bit
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/**
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* @addtogroup lavu_math
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* @{
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*/
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#if HAVE_FAST_CLZ
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#if !defined(ff_ctz) && (defined(__GNUC__) || AV_HAS_BUILTIN(__builtin_ctz))
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#define ff_ctz(v) __builtin_ctz(v)
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#endif
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#if !defined(ff_ctzll) && (defined(__GNUC__) || AV_HAS_BUILTIN(__builtin_ctzll))
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#define ff_ctzll(v) __builtin_ctzll(v)
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#endif
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#if !defined(ff_clz) && (defined(__GNUC__) || AV_HAS_BUILTIN(__builtin_clz))
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#define ff_clz(v) __builtin_clz(v)
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#endif
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#endif
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#ifndef ff_ctz
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#define ff_ctz ff_ctz_c
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/**
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* Trailing zero bit count.
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*
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* @param v input value. If v is 0, the result is undefined.
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* @return the number of trailing 0-bits
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*/
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/* We use the De-Bruijn method outlined in:
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* http://supertech.csail.mit.edu/papers/debruijn.pdf. */
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static av_always_inline av_const int ff_ctz_c(int v)
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{
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static const uint8_t debruijn_ctz32[32] = {
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0, 1, 28, 2, 29, 14, 24, 3, 30, 22, 20, 15, 25, 17, 4, 8,
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31, 27, 13, 23, 21, 19, 16, 7, 26, 12, 18, 6, 11, 5, 10, 9
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};
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return debruijn_ctz32[(uint32_t)((v & -(uint32_t)v) * 0x077CB531U) >> 27];
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}
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#endif
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#ifndef ff_ctzll
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#define ff_ctzll ff_ctzll_c
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/* We use the De-Bruijn method outlined in:
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* http://supertech.csail.mit.edu/papers/debruijn.pdf. */
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static av_always_inline av_const int ff_ctzll_c(long long v)
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{
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static const uint8_t debruijn_ctz64[64] = {
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0, 1, 2, 53, 3, 7, 54, 27, 4, 38, 41, 8, 34, 55, 48, 28,
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62, 5, 39, 46, 44, 42, 22, 9, 24, 35, 59, 56, 49, 18, 29, 11,
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63, 52, 6, 26, 37, 40, 33, 47, 61, 45, 43, 21, 23, 58, 17, 10,
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51, 25, 36, 32, 60, 20, 57, 16, 50, 31, 19, 15, 30, 14, 13, 12
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};
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return debruijn_ctz64[(uint64_t)((v & -(uint64_t)v) * 0x022FDD63CC95386DU) >> 58];
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}
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#endif
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#ifndef ff_clz
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#define ff_clz ff_clz_c
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static av_always_inline av_const unsigned ff_clz_c(unsigned x)
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{
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unsigned i = sizeof(x) * 8;
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while (x) {
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x >>= 1;
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i--;
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}
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return i;
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}
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#endif
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#if defined(__GNUC__) || AV_HAS_BUILTIN(__builtin_parity)
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#ifndef av_parity
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#define av_parity __builtin_parity
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#endif
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#endif
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/**
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* @}
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*/
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#endif /* AVUTIL_INTMATH_H */
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