FFmpeg
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 "libavutil/timer.h"
22 
23 #include <inttypes.h>
24 
25 #include "libavutil/softfloat.h"
26 #include "libavutil/common.h"
27 #include "libavutil/log.h"
28 
29 #include <stdio.h>
30 
31 static const SoftFloat FLOAT_0_017776489257 = {0x1234, 12};
32 static const SoftFloat FLOAT_1374_40625 = {0xabcd, 25};
33 static const SoftFloat FLOAT_0_1249694824218 = {0xFFF, 15};
34 
35 
36 int main(void){
37  SoftFloat one= av_int2sf(1, 0);
38  SoftFloat sf1, sf2, sf3;
39  double d1, d2, d3;
40  int i, j;
42 
43  d1= 1;
44  for(i= 0; i<10; i++){
45  d1= 1/(d1+1);
46  }
47  printf("test1 double=%d\n", (int)(d1 * (1<<24)));
48 
49  sf1= one;
50  for(i= 0; i<10; i++){
51  sf1= av_div_sf(one, av_normalize_sf(av_add_sf(one, sf1)));
52  }
53  printf("test1 sf =%d\n", av_sf2int(sf1, 24));
54 
55 
56  for(i= 0; i<100; i++){
58  d1= i;
59  d2= i/100.0;
60  for(j= 0; j<1000; j++){
61  d1= (d1+1)*d2;
62  }
63  STOP_TIMER("float add mul")
64  }
65  printf("test2 double=%d\n", (int)(d1 * (1<<24)));
66 
67  for(i= 0; i<100; i++){
69  sf1= av_int2sf(i, 0);
70  sf2= av_div_sf(av_int2sf(i, 2), av_int2sf(200, 3));
71  for(j= 0; j<1000; j++){
72  sf1= av_mul_sf(av_add_sf(sf1, one),sf2);
73  }
74  STOP_TIMER("softfloat add mul")
75  }
76  printf("test2 sf =%d (%d %d)\n", av_sf2int(sf1, 24), sf1.exp, sf1.mant);
77 
78  d1 = 0.0177764893;
79  d2 = 1374.40625;
80  d3 = 0.1249694824;
81  d2 += d1;
82  d3 += d2;
83  printf("test3 double: %.10lf\n", d3);
84 
86  sf2 = FLOAT_1374_40625;
88  sf2 = av_add_sf(sf1, sf2);
89  sf3 = av_add_sf(sf3, sf2);
90  printf("test3 softfloat: %.10lf (0x%08x %d)\n", (double)av_sf2double(sf3), sf3.mant, sf3.exp);
91 
92  sf1 = av_int2sf(0xFFFFFFF0, 0);
93  printf("test4 softfloat: %.10lf (0x%08x %d)\n", (double)av_sf2double(sf1), sf1.mant, sf1.exp);
94  sf1 = av_int2sf(0x00000010, 0);
95  printf("test4 softfloat: %.10lf (0x%08x %d)\n", (double)av_sf2double(sf1), sf1.mant, sf1.exp);
96 
97  sf1 = av_int2sf(0x1FFFFFFF, 0);
98  printf("test4 softfloat: %.10lf (0x%08x %d)\n", (double)av_sf2double(sf1), sf1.mant, sf1.exp);
99  sf1 = av_int2sf(0xE0000001, 0);
100  printf("test4 softfloat: %.10lf (0x%08x %d)\n", (double)av_sf2double(sf1), sf1.mant, sf1.exp);
101 
102 
103  sf1 = (SoftFloat){ 0x20000000, MIN_EXP };
104  sf1 = av_mul_sf(sf1, sf1);
105  printf("test5 softfloat: %.10lf (0x%08x %d)\n", (double)av_sf2double(sf1), sf1.mant, sf1.exp);
106 
107  sf1 = (SoftFloat){ 0x20000000, MIN_EXP };
108  sf2 = (SoftFloat){ 0x20000000, MAX_EXP };
109  i = av_cmp_sf(sf1, sf2);
110  j = av_cmp_sf(sf2, sf1);
111  sf1 = av_div_sf(sf1, sf2);
112  printf("test6 softfloat: %.10lf (0x%08x %d) %d %d\n", (double)av_sf2double(sf1), sf1.mant, sf1.exp, i, j);
113 
114  for(i= -50; i<50; i++) {
115  sf1= av_int2sf(i, 0);
116  for(j= -50; j<50; j++) {
117  int c;
118  sf2= av_int2sf(j, 0);
119  c = av_cmp_sf(sf1, sf2);
120  if (FFDIFFSIGN(i,j) != c && (FFDIFFSIGN(i,j)^c)<0) {
121  printf("av_cmp_sf failed at %d %d as %X\n", i, j, c);
122  }
123  c = av_gt_sf(sf1, sf2);
124  if ((i>j) != c) {
125  printf("av_gt_sf failed at %d %d as %X\n", i, j, c);
126  }
127  }
128  sf1 = av_int2sf(1, i);
129  for(j = -50; j < 50; j++) {
130  int c;
131  sf2 = av_int2sf(1, j);
132  c = av_cmp_sf(sf2, sf1);
133  if (FFDIFFSIGN(i,j) != c && (FFDIFFSIGN(i,j)^c) < 0) {
134  printf("av_cmp_sf failed2 at %d %d as %X\n", i, j, c);
135  }
136  c = av_gt_sf(sf1, sf2);
137  if ((i<j) != c) {
138  printf("av_gt_sf failed2 at %d %d as %X\n", i, j, c);
139  }
140  }
141  }
142 
143 
144  for(i= 0; i<4*36; i++){
145  int s, c;
146  double errs, errc;
147 
148  av_sincos_sf(i*(1ULL<<32)/36/4, &s, &c);
149  errs = (double)s/ (1<<30) - sin(i*M_PI/36);
150  errc = (double)c/ (1<<30) - cos(i*M_PI/36);
151  if (fabs(errs) > 0.00000002 || fabs(errc) >0.001) {
152  printf("sincos FAIL %d %f %f %f %f\n", i, (float)s/ (1<<30), (float)c/ (1<<30), sin(i*M_PI/36), cos(i*M_PI/36));
153  }
154 
155  }
156  return 0;
157 
158 }
static const SoftFloat FLOAT_1374_40625
Definition: softfloat.c:32
void av_log_set_level(int level)
Set the log level.
Definition: log.c:440
static av_const SoftFloat av_div_sf(SoftFloat a, SoftFloat b)
b has to be normalized and not zero.
Definition: softfloat.h:116
static av_const double av_sf2double(SoftFloat v)
Convert a SoftFloat to a double precision float.
Definition: softfloat.h:52
Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated Undefined Behavior must not occur in a C it is not safe even if the output of undefined operations is unused The unsafety may seem nit picking but Optimizing compilers have in fact optimized code on the assumption that no undefined Behavior occurs Optimizing code based on wrong assumptions can and has in some cases lead to effects beyond the output of computations The signed integer overflow problem in speed critical code Code which is highly optimized and works with signed integers sometimes has the problem that often the output of the computation does not c
Definition: undefined.txt:32
int32_t mant
Definition: softfloat.h:35
high precision timer, useful to profile code
static av_const SoftFloat av_normalize_sf(SoftFloat a)
Definition: softfloat.h:57
static const SoftFloat FLOAT_0_017776489257
Definition: softfloat.c:31
#define AV_LOG_DEBUG
Stuff which is only useful for libav* developers.
Definition: log.h:215
static av_unused void av_sincos_sf(int a, int *s, int *c)
Rounding-to-nearest used.
Definition: softfloat.h:240
#define FFDIFFSIGN(x, y)
Comparator.
Definition: common.h:92
static av_const int av_cmp_sf(SoftFloat a, SoftFloat b)
Compares two SoftFloats.
Definition: softfloat.h:138
#define s(width, name)
Definition: cbs_vp9.c:257
static av_const int av_gt_sf(SoftFloat a, SoftFloat b)
Compares two SoftFloats.
Definition: softfloat.h:150
static av_const int av_sf2int(SoftFloat v, int frac_bits)
Converts a SoftFloat to an integer.
Definition: softfloat.h:198
#define START_TIMER
Definition: timer.h:137
int main(void)
Definition: softfloat.c:36
#define MIN_EXP
Definition: softfloat.h:30
static av_const SoftFloat av_add_sf(SoftFloat a, SoftFloat b)
Definition: softfloat.h:162
common internal and external API header
static av_const SoftFloat av_mul_sf(SoftFloat a, SoftFloat b)
Definition: softfloat.h:102
int32_t exp
Definition: softfloat.h:36
#define STOP_TIMER(id)
Definition: timer.h:138
printf("static const uint8_t my_array[100] = {\n")
#define MAX_EXP
Definition: softfloat.h:31
static av_const SoftFloat av_int2sf(int v, int frac_bits)
Converts a mantisse and exponent to a SoftFloat.
Definition: softfloat.h:185
#define M_PI
Definition: mathematics.h:52
static const SoftFloat FLOAT_0_1249694824218
Definition: softfloat.c:33
int i
Definition: input.c:407