mirror of
https://git.ffmpeg.org/ffmpeg.git
synced 2024-12-23 15:53:08 +00:00
127 lines
3.5 KiB
C
127 lines
3.5 KiB
C
/*
|
|
* Copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
|
|
*
|
|
* 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_SOFTFLOAT_H
|
|
#define AVUTIL_SOFTFLOAT_H
|
|
|
|
#include <stdint.h>
|
|
#include "common.h"
|
|
|
|
#define MIN_EXP -126
|
|
#define MAX_EXP 126
|
|
#define ONE_BITS 29
|
|
|
|
typedef struct SoftFloat{
|
|
int32_t exp;
|
|
int32_t mant;
|
|
}SoftFloat;
|
|
|
|
static av_const SoftFloat av_normalize_sf(SoftFloat a){
|
|
if(a.mant){
|
|
#if 1
|
|
while((a.mant + 0x20000000U)<0x40000000U){
|
|
a.mant += a.mant;
|
|
a.exp -= 1;
|
|
}
|
|
#else
|
|
int s=ONE_BITS + 1 - av_log2(a.mant ^ (a.mant<<1));
|
|
a.exp -= s;
|
|
a.mant <<= s;
|
|
#endif
|
|
if(a.exp < MIN_EXP){
|
|
a.exp = MIN_EXP;
|
|
a.mant= 0;
|
|
}
|
|
}else{
|
|
a.exp= MIN_EXP;
|
|
}
|
|
return a;
|
|
}
|
|
|
|
static inline av_const SoftFloat av_normalize1_sf(SoftFloat a){
|
|
#if 1
|
|
if(a.mant + 0x40000000 < 0){
|
|
a.exp++;
|
|
a.mant>>=1;
|
|
}
|
|
return a;
|
|
#elif 1
|
|
int t= a.mant + 0x40000000 < 0;
|
|
return (SoftFloat){a.exp+t, a.mant>>t};
|
|
#else
|
|
int t= (a.mant + 0x40000000U)>>31;
|
|
return (SoftFloat){a.exp+t, a.mant>>t};
|
|
#endif
|
|
}
|
|
|
|
/**
|
|
* @return Will not be more denormalized than a+b. So if either input is
|
|
* normalized, then the output will not be worse then the other input.
|
|
* If both are normalized, then the output will be normalized.
|
|
*/
|
|
static inline av_const SoftFloat av_mul_sf(SoftFloat a, SoftFloat b){
|
|
a.exp += b.exp;
|
|
a.mant = (a.mant * (int64_t)b.mant) >> ONE_BITS;
|
|
return av_normalize1_sf(a);
|
|
}
|
|
|
|
/**
|
|
* b has to be normalized and not zero.
|
|
* @return Will not be more denormalized than a.
|
|
*/
|
|
static av_const SoftFloat av_div_sf(SoftFloat a, SoftFloat b){
|
|
a.exp -= b.exp+1;
|
|
a.mant = ((int64_t)a.mant<<(ONE_BITS+1)) / b.mant;
|
|
return av_normalize1_sf(a);
|
|
}
|
|
|
|
static inline av_const int av_cmp_sf(SoftFloat a, SoftFloat b){
|
|
int t= a.exp - b.exp;
|
|
if(t<0) return (a.mant >> (-t)) - b.mant ;
|
|
else return a.mant - (b.mant >> t);
|
|
}
|
|
|
|
static inline av_const SoftFloat av_add_sf(SoftFloat a, SoftFloat b){
|
|
int t= a.exp - b.exp;
|
|
if(t<0) return av_normalize1_sf((SoftFloat){b.exp, b.mant + (a.mant >> (-t))});
|
|
else return av_normalize1_sf((SoftFloat){a.exp, a.mant + (b.mant >> t )});
|
|
}
|
|
|
|
static inline av_const SoftFloat av_sub_sf(SoftFloat a, SoftFloat b){
|
|
return av_add_sf(a, (SoftFloat){b.exp, -b.mant});
|
|
}
|
|
|
|
//FIXME sqrt, log, exp, pow, sin, cos
|
|
|
|
static inline av_const SoftFloat av_int2sf(int v, int frac_bits){
|
|
return av_normalize_sf((SoftFloat){ONE_BITS-frac_bits, v});
|
|
}
|
|
|
|
/**
|
|
* Rounding is to -inf.
|
|
*/
|
|
static inline av_const int av_sf2int(SoftFloat v, int frac_bits){
|
|
v.exp += frac_bits - ONE_BITS;
|
|
if(v.exp >= 0) return v.mant << v.exp ;
|
|
else return v.mant >>(-v.exp);
|
|
}
|
|
|
|
#endif /* AVUTIL_SOFTFLOAT_H */
|