mirror of
https://github.com/librempeg/librempeg
synced 2024-11-22 00:51:37 +00:00
116 lines
3.6 KiB
C
116 lines
3.6 KiB
C
/*
|
|
* Copyright (c) 2016 Umair Khan <omerjerk@gmail.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_SOFTFLOAT_IEEE754_H
|
|
#define AVUTIL_SOFTFLOAT_IEEE754_H
|
|
|
|
#include <stdint.h>
|
|
|
|
#define EXP_BIAS 127
|
|
#define MANT_BITS 23
|
|
|
|
typedef struct SoftFloat_IEEE754 {
|
|
int32_t sign;
|
|
uint64_t mant;
|
|
int32_t exp;
|
|
} SoftFloat_IEEE754;
|
|
|
|
static const SoftFloat_IEEE754 FLOAT_0 = {0, 0, -126};
|
|
static const SoftFloat_IEEE754 FLOAT_1 = {0, 0, 0};
|
|
|
|
/** Normalize the softfloat as defined by IEEE 754 single-recision floating
|
|
* point specification
|
|
*/
|
|
static inline SoftFloat_IEEE754 av_normalize_sf_ieee754(SoftFloat_IEEE754 sf) {
|
|
while( sf.mant >= 0x1000000UL ) {
|
|
sf.exp++;
|
|
sf.mant >>= 1;
|
|
}
|
|
sf.mant &= 0x007fffffUL;
|
|
return sf;
|
|
}
|
|
|
|
/** Convert integer to softfloat.
|
|
* @return softfloat with value n * 2^e
|
|
*/
|
|
static inline SoftFloat_IEEE754 av_int2sf_ieee754(int64_t n, int e) {
|
|
int sign = 0;
|
|
|
|
if (n < 0) {
|
|
sign = 1;
|
|
n *= -1;
|
|
}
|
|
return av_normalize_sf_ieee754((SoftFloat_IEEE754) {sign, n << MANT_BITS, 0 + e});
|
|
}
|
|
|
|
/** Make a softfloat out of the bitstream. Assumes the bits are in the form as defined
|
|
* by the IEEE 754 spec.
|
|
*/
|
|
static inline SoftFloat_IEEE754 av_bits2sf_ieee754(uint32_t n) {
|
|
return ((SoftFloat_IEEE754) { (n & 0x80000000UL) >> 31, (n & 0x7FFFFFUL), (int8_t)((n & 0x7F800000UL) >> 23)});
|
|
}
|
|
|
|
/** Convert the softfloat to integer
|
|
*/
|
|
static inline int av_sf2int_ieee754(SoftFloat_IEEE754 a) {
|
|
if(a.exp >= 0) return a.mant << a.exp ;
|
|
else return a.mant >>(-a.exp);
|
|
}
|
|
|
|
/** Divide a by b. b should not be zero.
|
|
* @return normalized result
|
|
*/
|
|
static inline SoftFloat_IEEE754 av_div_sf_ieee754(SoftFloat_IEEE754 a, SoftFloat_IEEE754 b) {
|
|
int32_t mant, exp, sign;
|
|
a = av_normalize_sf_ieee754(a);
|
|
b = av_normalize_sf_ieee754(b);
|
|
sign = a.sign ^ b.sign;
|
|
mant = ((((uint64_t) (a.mant | 0x00800000UL)) << MANT_BITS) / (b.mant| 0x00800000UL));
|
|
exp = a.exp - b.exp;
|
|
return av_normalize_sf_ieee754((SoftFloat_IEEE754) {sign, mant, exp});
|
|
}
|
|
|
|
/** Multiply a with b
|
|
* #return normalized result
|
|
*/
|
|
static inline SoftFloat_IEEE754 av_mul_sf_ieee754(SoftFloat_IEEE754 a, SoftFloat_IEEE754 b) {
|
|
int32_t sign, mant, exp;
|
|
a = av_normalize_sf_ieee754(a);
|
|
b = av_normalize_sf_ieee754(b);
|
|
sign = a.sign ^ b.sign;
|
|
mant = (((uint64_t)(a.mant|0x00800000UL) * (uint64_t)(b.mant|0x00800000UL))>>MANT_BITS);
|
|
exp = a.exp + b.exp;
|
|
return av_normalize_sf_ieee754((SoftFloat_IEEE754) {sign, mant, exp});
|
|
}
|
|
|
|
/** Compare a with b strictly
|
|
* @returns 1 if the a and b are equal, 0 otherwise.
|
|
*/
|
|
static inline int av_cmp_sf_ieee754(SoftFloat_IEEE754 a, SoftFloat_IEEE754 b) {
|
|
a = av_normalize_sf_ieee754(a);
|
|
b = av_normalize_sf_ieee754(b);
|
|
if (a.sign != b.sign) return 0;
|
|
if (a.mant != b.mant) return 0;
|
|
if (a.exp != b.exp ) return 0;
|
|
return 1;
|
|
}
|
|
|
|
#endif /*AVUTIL_SOFTFLOAT_IEEE754_H*/
|