2 * portable IEEE float/double read/write functions
4 * Copyright (c) 2005 Michael Niedermayer <michaelni@gmx.at>
6 * This file is part of FFmpeg.
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
25 * portable IEEE float/double read/write functions
30 #include "mathematics.h"
31 #include "intfloat_readwrite.h"
35 double av_int2dbl(int64_t v
){
36 if((uint64_t)v
+v
> 0xFFEULL
<<52)
38 return ldexp(((v
&((1LL<<52)-1)) + (1LL<<52)) * (v
>>63|1), (v
>>52&0x7FF)-1075);
41 float av_int2flt(int32_t v
){
42 if((uint32_t)v
+v
> 0xFF000000U
)
44 return ldexp(((v
&0x7FFFFF) + (1<<23)) * (v
>>31|1), (v
>>23&0xFF)-150);
47 double av_ext2dbl(const AVExtFloat ext
){
51 for (i
= 0; i
< 8; i
++)
52 m
= (m
<<8) + ext
.mantissa
[i
];
53 e
= (((int)ext
.exponent
[0]&0x7f)<<8) | ext
.exponent
[1];
56 e
-= 16383 + 63; /* In IEEE 80 bits, the whole (i.e. 1.xxxx)
57 * mantissa bit is written as opposed to the
58 * single and double precision formats. */
59 if (ext
.exponent
[0]&0x80)
64 int64_t av_dbl2int(double d
){
67 else if(d
-d
) return 0x7FF0000000000000LL
+ ((int64_t)(d
<0)<<63) + (d
!=d
);
69 return (int64_t)(d
<0)<<63 | (e
+1022LL)<<52 | (int64_t)((fabs(d
)-0.5)*(1LL<<53));
72 int32_t av_flt2int(float d
){
75 else if(d
-d
) return 0x7F800000 + ((d
<0)<<31) + (d
!=d
);
77 return (d
<0)<<31 | (e
+126)<<23 | (int64_t)((fabs(d
)-0.5)*(1<<24));
80 AVExtFloat
av_dbl2ext(double d
){
81 struct AVExtFloat ext
= {{0}};
82 int e
, i
; double f
; uint64_t m
;
84 f
= fabs(frexp(d
, &e
));
85 if (f
>= 0.5 && f
< 1) {
87 ext
.exponent
[0] = e
>>8;
89 m
= (uint64_t)ldexp(f
, 64);
91 ext
.mantissa
[i
] = m
>>(56-(i
<<3));
92 } else if (f
!= 0.0) {
93 ext
.exponent
[0] = 0x7f; ext
.exponent
[1] = 0xff;
98 ext
.exponent
[0] |= 0x80;
101 #endif /* FF_API_INTFLOAT */