mirror of https://github.com/FFmpeg/FFmpeg.git
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
171 lines
4.0 KiB
171 lines
4.0 KiB
/* |
|
* 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 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 |
|
#ifndef ff_ctzll |
|
#define ff_ctzll(v) __builtin_ctzll(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 |
|
*/ |
|
#if !defined( _MSC_VER ) |
|
/* 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]; |
|
} |
|
#else |
|
static av_always_inline av_const int ff_ctz_c( int v ) |
|
{ |
|
unsigned long c; |
|
_BitScanForward(&c, v); |
|
return c; |
|
} |
|
#endif |
|
#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) * 0x022FDD63CC95386D) >> 58]; |
|
} |
|
#endif |
|
|
|
/** |
|
* @} |
|
*/ |
|
#endif /* AVUTIL_INTMATH_H */
|
|
|