FFmpeg coverage

Directory: ../../../ffmpeg/
File: src/libavutil/softfloat.h
Date: 2026-01-08 00:53:43
Exec Total Coverage
Lines: 94 103 91.3%
Functions: 10 10 100.0%
Branches: 30 38 78.9%
Line Branch Exec Source
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 #ifndef AVUTIL_SOFTFLOAT_H
22 #define AVUTIL_SOFTFLOAT_H
23
24 #include <stdint.h>
25 #include "common.h"
26
27 #include "avassert.h"
28 #include "softfloat_tables.h"
29
30 #define MIN_EXP -149
31 #define MAX_EXP 126
32 #define ONE_BITS 29
33
34 typedef struct SoftFloat{
35 int32_t mant;
36 int32_t exp;
37 }SoftFloat;
38
39 static const SoftFloat FLOAT_0 = { 0, MIN_EXP}; ///< 0.0
40 static const SoftFloat FLOAT_05 = { 0x20000000, 0}; ///< 0.5
41 static const SoftFloat FLOAT_1 = { 0x20000000, 1}; ///< 1.0
42 static const SoftFloat FLOAT_EPSILON = { 0x29F16B12, -16}; ///< A small value
43 static const SoftFloat FLOAT_1584893192 = { 0x32B771ED, 1}; ///< 1.584893192 (10^.2)
44 static const SoftFloat FLOAT_100000 = { 0x30D40000, 17}; ///< 100000
45 static const SoftFloat FLOAT_0999999 = { 0x3FFFFBCE, 0}; ///< 0.999999
46 static const SoftFloat FLOAT_MIN = { 0x20000000, MIN_EXP};
47
48
49 /**
50 * Convert a SoftFloat to a double precision float.
51 */
52 static inline av_const double av_sf2double(SoftFloat v) {
53 v.exp -= ONE_BITS +1;
54 return ldexp(v.mant, v.exp);
55 }
56
57 8669801 static av_const SoftFloat av_normalize_sf(SoftFloat a){
58
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 8669801 if(a.mant){
59 #if 1
60
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 11117286 while((a.mant + 0x1FFFFFFFU)<0x3FFFFFFFU){
61 2600785 a.mant += a.mant;
62 2600785 a.exp -= 1;
63 }
64 #else
65 int s=ONE_BITS - av_log2(FFABS(a.mant));
66 a.exp -= s;
67 a.mant <<= s;
68 #endif
69
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 8516501 if(a.exp < MIN_EXP){
70 ✗ a.exp = MIN_EXP;
71 ✗ a.mant= 0;
72 }
73 }else{
74 153300 a.exp= MIN_EXP;
75 }
76 8669801 return a;
77 }
78
79 18108978 static inline av_const SoftFloat av_normalize1_sf(SoftFloat a){
80 #if 1
81
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 18108978 if((int32_t)(a.mant + 0x40000000U) <= 0){
82 6405732 a.exp++;
83 6405732 a.mant>>=1;
84 }
85 av_assert2(a.mant < 0x40000000 && a.mant > -0x40000000);
86 av_assert2(a.exp <= MAX_EXP);
87 18108978 return a;
88 #elif 1
89 int t= a.mant + 0x40000000 < 0;
90 return (SoftFloat){ a.mant>>t, a.exp+t};
91 #else
92 int t= (a.mant + 0x3FFFFFFFU)>>31;
93 return (SoftFloat){a.mant>>t, a.exp+t};
94 #endif
95 }
96
97 /**
98 * @return Will not be more denormalized than a*b. So if either input is
99 * normalized, then the output will not be worse then the other input.
100 * If both are normalized, then the output will be normalized.
101 */
102 8723947 static inline av_const SoftFloat av_mul_sf(SoftFloat a, SoftFloat b){
103 8723947 a.exp += b.exp;
104 av_assert2((int32_t)((a.mant * (int64_t)b.mant) >> ONE_BITS) == (a.mant * (int64_t)b.mant) >> ONE_BITS);
105 8723947 a.mant = (a.mant * (int64_t)b.mant) >> ONE_BITS;
106 8723947 a = av_normalize1_sf((SoftFloat){a.mant, a.exp - 1});
107
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 8723947 if (!a.mant || a.exp < MIN_EXP)
108 396776 return FLOAT_0;
109 8327171 return a;
110 }
111
112 /**
113 * b has to be normalized and not zero.
114 * @return Will not be more denormalized than a.
115 */
116 715230 static inline av_const SoftFloat av_div_sf(SoftFloat a, SoftFloat b){
117 715230 int64_t temp = (int64_t)a.mant * (1<<(ONE_BITS+1));
118 715230 temp /= b.mant;
119 715230 a.exp -= b.exp;
120 715230 a.mant = temp;
121
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 715230 while (a.mant != temp) {
122 ✗ temp /= 2;
123 ✗ a.exp--;
124 ✗ a.mant = temp;
125 }
126 715230 a = av_normalize1_sf(a);
127
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 715230 if (!a.mant || a.exp < MIN_EXP)
128 1218 return FLOAT_0;
129 714012 return a;
130 }
131
132 /**
133 * Compares two SoftFloats.
134 * @returns < 0 if the first is less
135 * > 0 if the first is greater
136 * 0 if they are equal
137 */
138 static inline av_const int av_cmp_sf(SoftFloat a, SoftFloat b){
139 int t= a.exp - b.exp;
140 if (t <-31) return - b.mant ;
141 else if (t < 0) return (a.mant >> (-t)) - b.mant ;
142 else if (t < 32) return a.mant - (b.mant >> t);
143 else return a.mant ;
144 }
145
146 /**
147 * Compares two SoftFloats.
148 * @returns 1 if a is greater than b, 0 otherwise
149 */
150 291082 static inline av_const int av_gt_sf(SoftFloat a, SoftFloat b)
151 {
152 291082 int t= a.exp - b.exp;
153
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 291082 if (t <-31) return 0 > b.mant ;
154
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 291082 else if (t < 0) return (a.mant >> (-t)) > b.mant ;
155
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 127213 else if (t < 32) return a.mant > (b.mant >> t);
156 ✗ else return a.mant > 0 ;
157 }
158
159 /**
160 * @returns the sum of 2 SoftFloats.
161 */
162 8247791 static inline av_const SoftFloat av_add_sf(SoftFloat a, SoftFloat b){
163 8247791 int t= a.exp - b.exp;
164
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 8247791 if (t <-31) return b;
165
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 8113265 else if (t < 0) return av_normalize_sf(av_normalize1_sf((SoftFloat){ b.mant + (a.mant >> (-t)), b.exp}));
166
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 7079641 else if (t < 32) return av_normalize_sf(av_normalize1_sf((SoftFloat){ a.mant + (b.mant >> t ), a.exp}));
167 258726 else return a;
168 }
169
170 /**
171 * @returns the difference of 2 SoftFloats.
172 */
173 333629 static inline av_const SoftFloat av_sub_sf(SoftFloat a, SoftFloat b){
174 333629 return av_add_sf(a, (SoftFloat){ -b.mant, b.exp});
175 }
176
177 //FIXME log, exp, pow
178
179 /**
180 * Converts a mantisse and exponent to a SoftFloat.
181 * This converts a fixed point value v with frac_bits fractional bits to a
182 * SoftFloat.
183 * @returns a SoftFloat with value v * 2^-frac_bits
184 */
185 815262 static inline av_const SoftFloat av_int2sf(int v, int frac_bits){
186 815262 int exp_offset = 0;
187
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 815262 if(v <= INT_MIN + 1){
188 ✗ exp_offset = 1;
189 ✗ v>>=1;
190 }
191 815262 return av_normalize_sf(av_normalize1_sf((SoftFloat){v, ONE_BITS + 1 - frac_bits + exp_offset}));
192 }
193
194 /**
195 * Converts a SoftFloat to an integer.
196 * Rounding is to -inf.
197 */
198 static inline av_const int av_sf2int(SoftFloat v, int frac_bits){
199 v.exp += frac_bits - (ONE_BITS + 1);
200 if(v.exp >= 0) return v.mant << v.exp ;
201 else return v.mant >>(-v.exp);
202 }
203
204 /**
205 * Rounding-to-nearest used.
206 */
207 428135 static av_always_inline SoftFloat av_sqrt_sf(SoftFloat val)
208 {
209 int tabIndex, rem;
210
211
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 428135 if (val.mant == 0)
212 126160 val.exp = MIN_EXP;
213
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 301975 else if (val.mant < 0)
214 ✗ abort();
215 else
216 {
217 301975 tabIndex = (val.mant - 0x20000000) >> 20;
218
219 301975 rem = val.mant & 0xFFFFF;
220 301975 val.mant = (int)(((int64_t)av_sqrttbl_sf[tabIndex] * (0x100000 - rem) +
221 301975 (int64_t)av_sqrttbl_sf[tabIndex + 1] * rem +
222 301975 0x80000) >> 20);
223 301975 val.mant = (int)(((int64_t)av_sqr_exp_multbl_sf[val.exp & 1] * val.mant +
224 301975 0x10000000) >> 29);
225
226
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 301975 if (val.mant < 0x40000000)
227 143712 val.exp -= 2;
228 else
229 158263 val.mant >>= 1;
230
231 301975 val.exp = (val.exp >> 1) + 1;
232 }
233
234 428135 return val;
235 }
236
237 /**
238 * Rounding-to-nearest used.
239 *
240 * @param a angle in units of (1ULL<<30)/M_PI radians
241 * @param s pointer to where sine in units of (1<<30) is returned
242 * @param c pointer to where cosine in units of (1<<30) is returned
243 */
244 32256 av_unused static void av_sincos_sf(int a, int *s, int *c)
245 {
246 int idx, sign;
247 int sv, cv;
248 int st, ct;
249
250 32256 idx = a >> 26;
251 32256 sign = (int32_t)((unsigned)idx << 27) >> 31;
252 32256 cv = av_costbl_1_sf[idx & 0xf];
253 32256 cv = (cv ^ sign) - sign;
254
255 32256 idx -= 8;
256 32256 sign = (int32_t)((unsigned)idx << 27) >> 31;
257 32256 sv = av_costbl_1_sf[idx & 0xf];
258 32256 sv = (sv ^ sign) - sign;
259
260 32256 idx = a >> 21;
261 32256 ct = av_costbl_2_sf[idx & 0x1f];
262 32256 st = av_sintbl_2_sf[idx & 0x1f];
263
264 32256 idx = (int)(((int64_t)cv * ct - (int64_t)sv * st + 0x20000000) >> 30);
265
266 32256 sv = (int)(((int64_t)cv * st + (int64_t)sv * ct + 0x20000000) >> 30);
267
268 32256 cv = idx;
269
270 32256 idx = a >> 16;
271 32256 ct = av_costbl_3_sf[idx & 0x1f];
272 32256 st = av_sintbl_3_sf[idx & 0x1f];
273
274 32256 idx = (int)(((int64_t)cv * ct - (int64_t)sv * st + 0x20000000) >> 30);
275
276 32256 sv = (int)(((int64_t)cv * st + (int64_t)sv * ct + 0x20000000) >> 30);
277 32256 cv = idx;
278
279 32256 idx = a >> 11;
280
281 32256 ct = (int)(((int64_t)av_costbl_4_sf[idx & 0x1f] * (0x800 - (a & 0x7ff)) +
282 32256 (int64_t)av_costbl_4_sf[(idx & 0x1f)+1]*(a & 0x7ff) +
283 32256 0x400) >> 11);
284 32256 st = (int)(((int64_t)av_sintbl_4_sf[idx & 0x1f] * (0x800 - (a & 0x7ff)) +
285 32256 (int64_t)av_sintbl_4_sf[(idx & 0x1f) + 1] * (a & 0x7ff) +
286 32256 0x400) >> 11);
287
288 32256 *c = (int)(((int64_t)cv * ct - (int64_t)sv * st + 0x20000000) >> 30);
289
290 32256 *s = (int)(((int64_t)cv * st + (int64_t)sv * ct + 0x20000000) >> 30);
291 32256 }
292
293 #endif /* AVUTIL_SOFTFLOAT_H */
294