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/*
* Copyright (c) 2015 James Almer
*
* 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_X86_INTMATH_H
#define AVUTIL_X86_INTMATH_H
#include <stdint.h>
#include "config.h"
#if HAVE_FAST_CLZ
#if defined(__INTEL_COMPILER)
# define ff_log2(x) (_bit_scan_reverse((x)|1))
# define ff_log2_16bit av_log2
# define ff_ctz(v) _bit_scan_forward(v)
# define ff_ctzll ff_ctzll_x86
static av_always_inline av_const int ff_ctzll_x86(long long v)
{
# if ARCH_X86_64
uint64_t c;
__asm__("bsfq %1,%0" : "=r" (c) : "r" (v));
return c;
# else
return ((uint32_t)v == 0) ? _bit_scan_forward((uint32_t)(v >> 32)) + 32 : _bit_scan_forward((uint32_t)v);
# endif
}
#elif defined(_MSC_VER)
# define ff_log2 ff_log2_x86
static av_always_inline av_const int ff_log2_x86(unsigned int v) {
unsigned long n;
_BitScanReverse(&n, v | 1);
return n;
}
# define ff_log2_16bit av_log2
# define ff_ctz ff_ctz_x86
static av_always_inline av_const int ff_ctz_x86(int v) {
unsigned long c;
_BitScanForward(&c, v);
return c;
}
# define ff_ctzll ff_ctzll_x86
static av_always_inline av_const int ff_ctzll_x86(long long v)
{
unsigned long c;
# if ARCH_X86_64
_BitScanForward64(&c, v);
# else
if ((uint32_t)v == 0) {
_BitScanForward(&c, (uint32_t)(v >> 32));
c += 32;
} else {
_BitScanForward(&c, (uint32_t)v);
}
# endif
return c;
}
#endif /* __INTEL_COMPILER */
#endif /* HAVE_FAST_CLZ */
#if defined(__GNUC__)
/* Our generic version of av_popcount is faster than GCC's built-in on
* CPUs that don't support the popcnt instruction.
*/
#if defined(__POPCNT__)
#define av_popcount __builtin_popcount
#if ARCH_X86_64
#define av_popcount64 __builtin_popcountll
#endif
#endif /* __POPCNT__ */
#if defined(__BMI2__)
#if AV_GCC_VERSION_AT_LEAST(5,1)
#define av_mod_uintp2 __builtin_ia32_bzhi_si
#elif HAVE_INLINE_ASM
/* GCC releases before 5.1.0 have a broken bzhi builtin, so for those we
* implement it using inline assembly
*/
#define av_mod_uintp2 av_mod_uintp2_bmi2
static av_always_inline av_const unsigned av_mod_uintp2_bmi2(unsigned a, unsigned p)
{
if (av_builtin_constant_p(p))
return a & ((1 << p) - 1);
else {
unsigned x;
__asm__ ("bzhi %2, %1, %0 \n\t" : "=r"(x) : "rm"(a), "r"(p));
return x;
}
}
#endif /* AV_GCC_VERSION_AT_LEAST */
#endif /* __BMI2__ */
#endif /* __GNUC__ */
#endif /* AVUTIL_X86_INTMATH_H */
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