1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
|
/*
* portable IEEE float/double read/write functions
*
* Copyright (c) 2005 Michael Niedermayer <michaelni@gmx.at>
*
* This file is part of Libav.
*
* Libav 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.
*
* Libav 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 Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* portable IEEE float/double read/write functions
*/
#include <stdint.h>
#include "mathematics.h"
#include "intfloat_readwrite.h"
double av_int2dbl(int64_t v){
if(v+v > 0xFFEULL<<52)
return NAN;
return ldexp(((v&((1LL<<52)-1)) + (1LL<<52)) * (v>>63|1), (v>>52&0x7FF)-1075);
}
float av_int2flt(int32_t v){
if(v+v > 0xFF000000U)
return NAN;
return ldexp(((v&0x7FFFFF) + (1<<23)) * (v>>31|1), (v>>23&0xFF)-150);
}
double av_ext2dbl(const AVExtFloat ext){
uint64_t m = 0;
int e, i;
for (i = 0; i < 8; i++)
m = (m<<8) + ext.mantissa[i];
e = (((int)ext.exponent[0]&0x7f)<<8) | ext.exponent[1];
if (e == 0x7fff && m)
return NAN;
e -= 16383 + 63; /* In IEEE 80 bits, the whole (i.e. 1.xxxx)
* mantissa bit is written as opposed to the
* single and double precision formats. */
if (ext.exponent[0]&0x80)
m= -m;
return ldexp(m, e);
}
int64_t av_dbl2int(double d){
int e;
if ( !d) return 0;
else if(d-d) return 0x7FF0000000000000LL + ((int64_t)(d<0)<<63) + (d!=d);
d= frexp(d, &e);
return (int64_t)(d<0)<<63 | (e+1022LL)<<52 | (int64_t)((fabs(d)-0.5)*(1LL<<53));
}
int32_t av_flt2int(float d){
int e;
if ( !d) return 0;
else if(d-d) return 0x7F800000 + ((d<0)<<31) + (d!=d);
d= frexp(d, &e);
return (d<0)<<31 | (e+126)<<23 | (int64_t)((fabs(d)-0.5)*(1<<24));
}
AVExtFloat av_dbl2ext(double d){
struct AVExtFloat ext= {{0}};
int e, i; double f; uint64_t m;
f = fabs(frexp(d, &e));
if (f >= 0.5 && f < 1) {
e += 16382;
ext.exponent[0] = e>>8;
ext.exponent[1] = e;
m = (uint64_t)ldexp(f, 64);
for (i=0; i < 8; i++)
ext.mantissa[i] = m>>(56-(i<<3));
} else if (f != 0.0) {
ext.exponent[0] = 0x7f; ext.exponent[1] = 0xff;
if (f != INFINITY)
ext.mantissa[0] = ~0;
}
if (d < 0)
ext.exponent[0] |= 0x80;
return ext;
}
|
