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softfloat.c
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1 /*
2  * copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 #include <inttypes.h>
22 #include <stdio.h>
23 #include "softfloat.h"
24 #include "common.h"
25 #include "log.h"
26 
27 #undef printf
28 
29 static const SoftFloat FLOAT_0_017776489257 = {0x1234, 12};
30 static const SoftFloat FLOAT_1374_40625 = {0xabcd, 25};
31 static const SoftFloat FLOAT_0_1249694824218 = {0xFFF, 15};
32 
33 
34 static av_const double av_sf2double(SoftFloat v) {
35  v.exp -= ONE_BITS +1;
36  if(v.exp > 0) return (double)v.mant * (double)(1 << v.exp);
37  else return (double)v.mant / (double)(1 << (-v.exp));
38 }
39 
40 int main(void){
41  SoftFloat one= av_int2sf(1, 0);
42  SoftFloat sf1, sf2, sf3;
43  double d1, d2, d3;
44  int i, j;
46 
47  d1= 1;
48  for(i= 0; i<10; i++){
49  d1= 1/(d1+1);
50  }
51  printf("test1 double=%d\n", (int)(d1 * (1<<24)));
52 
53  sf1= one;
54  for(i= 0; i<10; i++){
55  sf1= av_div_sf(one, av_normalize_sf(av_add_sf(one, sf1)));
56  }
57  printf("test1 sf =%d\n", av_sf2int(sf1, 24));
58 
59 
60  for(i= 0; i<100; i++){
62  d1= i;
63  d2= i/100.0;
64  for(j= 0; j<1000; j++){
65  d1= (d1+1)*d2;
66  }
67  STOP_TIMER("float add mul")
68  }
69  printf("test2 double=%d\n", (int)(d1 * (1<<24)));
70 
71  for(i= 0; i<100; i++){
73  sf1= av_int2sf(i, 0);
74  sf2= av_div_sf(av_int2sf(i, 2), av_int2sf(200, 3));
75  for(j= 0; j<1000; j++){
76  sf1= av_mul_sf(av_add_sf(sf1, one),sf2);
77  }
78  STOP_TIMER("softfloat add mul")
79  }
80  printf("test2 sf =%d (%d %d)\n", av_sf2int(sf1, 24), sf1.exp, sf1.mant);
81 
82  d1 = 0.0177764893;
83  d2 = 1374.40625;
84  d3 = 0.1249694824;
85  d2 += d1;
86  d3 += d2;
87  printf("test3 double: %.10lf\n", d3);
88 
90  sf2 = FLOAT_1374_40625;
92  sf2 = av_add_sf(sf1, sf2);
93  sf3 = av_add_sf(sf3, sf2);
94  printf("test3 softfloat: %.10lf (0x%08x %d)\n", (double)av_sf2double(sf3), sf3.mant, sf3.exp);
95 
96  return 0;
97 
98 }