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/*
* 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
/**
* @addtogroup lavu_internal
* @{
*/
#if HAVE_FAST_CLZ
#if defined( __INTEL_COMPILER )
#ifndef ff_log2
# define ff_log2(x) (_bit_scan_reverse((x)|1))
# ifndef ff_log2_16bit
# define ff_log2_16bit av_log2
# endif
#endif /* ff_log2 */
#elif 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
#if !defined( _MSC_VER )
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;
}
#else
static av_always_inline av_const int ff_log2_c(unsigned int v)
{
unsigned long n;
_BitScanReverse(&n, v|1);
return n;
}
#define ff_log2_16bit av_log2
#endif
#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 defined( __INTEL_COMPILER )
#ifndef ff_ctz
#define ff_ctz(v) _bit_scan_forward(v)
#endif
#elif AV_GCC_VERSION_AT_LEAST(3,4)
#ifndef ff_ctz
#define ff_ctz(v) __builtin_ctz(v)
#endif
#endif
#endif
#ifndef ff_ctz
#define ff_ctz ff_ctz_c
#if !defined( _MSC_VER )
static av_always_inline av_const int ff_ctz_c(int v)
{
int c;
if (v & 0x1)
return 0;
c = 1;
if (!(v & 0xffff)) {
v >>= 16;
c += 16;
}
if (!(v & 0xff)) {
v >>= 8;
c += 8;
}
if (!(v & 0xf)) {
v >>= 4;
c += 4;
}
if (!(v & 0x3)) {
v >>= 2;
c += 2;
}
c -= v & 0x1;
return c;
}
#else
static av_always_inline av_const int ff_ctz_c( int v )
{
unsigned long c;
_BitScanForward(&c, v);
return c;
}
#endif
#endif
/**
* Trailing zero bit count.
*
* @param v input value. If v is 0, the result is undefined.
* @return the number of trailing 0-bits
*/
int av_ctz(int v);
/**
* @}
*/
#endif /* AVUTIL_INTMATH_H */
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