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softfloat.h
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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 #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{
37 }SoftFloat;
38 
39 static const SoftFloat FLOAT_0 = { 0, MIN_EXP};
40 static const SoftFloat FLOAT_05 = { 0x20000000, 0};
41 static const SoftFloat FLOAT_1 = { 0x20000000, 1};
42 static const SoftFloat FLOAT_EPSILON = { 0x29F16B12, -16};
43 static const SoftFloat FLOAT_1584893192 = { 0x32B771ED, 1};
44 static const SoftFloat FLOAT_100000 = { 0x30D40000, 17};
45 static const SoftFloat FLOAT_0999999 = { 0x3FFFFBCE, 0};
46 static const SoftFloat FLOAT_MIN = { 0x20000000, MIN_EXP};
47 
48 static inline av_const double av_sf2double(SoftFloat v) {
49  v.exp -= ONE_BITS +1;
50  if(v.exp > 0) return (double)v.mant * (double)(1 << v.exp);
51  else return (double)v.mant / (double)(1 << (-v.exp));
52 }
53 
55  if(a.mant){
56 #if 1
57  while((a.mant + 0x1FFFFFFFU)<0x3FFFFFFFU){
58  a.mant += a.mant;
59  a.exp -= 1;
60  }
61 #else
62  int s=ONE_BITS - av_log2(FFABS(a.mant));
63  a.exp -= s;
64  a.mant <<= s;
65 #endif
66  if(a.exp < MIN_EXP){
67  a.exp = MIN_EXP;
68  a.mant= 0;
69  }
70  }else{
71  a.exp= MIN_EXP;
72  }
73  return a;
74 }
75 
77 #if 1
78  if((int32_t)(a.mant + 0x40000000U) <= 0){
79  a.exp++;
80  a.mant>>=1;
81  }
82  av_assert2(a.mant < 0x40000000 && a.mant > -0x40000000);
83  return a;
84 #elif 1
85  int t= a.mant + 0x40000000 < 0;
86  return (SoftFloat){ a.mant>>t, a.exp+t};
87 #else
88  int t= (a.mant + 0x3FFFFFFFU)>>31;
89  return (SoftFloat){a.mant>>t, a.exp+t};
90 #endif
91 }
92 
93 /**
94  * @return Will not be more denormalized than a*b. So if either input is
95  * normalized, then the output will not be worse then the other input.
96  * If both are normalized, then the output will be normalized.
97  */
99  a.exp += b.exp;
100  av_assert2((int32_t)((a.mant * (int64_t)b.mant) >> ONE_BITS) == (a.mant * (int64_t)b.mant) >> ONE_BITS);
101  a.mant = (a.mant * (int64_t)b.mant) >> ONE_BITS;
102  a = av_normalize1_sf((SoftFloat){a.mant, a.exp - 1});
103  if (!a.mant || a.exp < MIN_EXP)
104  return FLOAT_0;
105  return a;
106 }
107 
108 /**
109  * b has to be normalized and not zero.
110  * @return Will not be more denormalized than a.
111  */
113  int64_t temp = (int64_t)a.mant * (1<<(ONE_BITS+1));
114  temp /= b.mant;
115  a.exp -= b.exp;
116  a.mant = temp;
117  while (a.mant != temp) {
118  temp /= 2;
119  a.exp--;
120  a.mant = temp;
121  }
122  a = av_normalize1_sf(a);
123  if (!a.mant || a.exp < MIN_EXP)
124  return FLOAT_0;
125  return a;
126 }
127 
128 static inline av_const int av_cmp_sf(SoftFloat a, SoftFloat b){
129  int t= a.exp - b.exp;
130  if (t <-31) return - b.mant ;
131  else if (t < 0) return (a.mant >> (-t)) - b.mant ;
132  else if (t < 32) return a.mant - (b.mant >> t);
133  else return a.mant ;
134 }
135 
136 static inline av_const int av_gt_sf(SoftFloat a, SoftFloat b)
137 {
138  int t= a.exp - b.exp;
139  if (t <-31) return 0 > b.mant ;
140  else if (t < 0) return (a.mant >> (-t)) > b.mant ;
141  else if (t < 32) return a.mant > (b.mant >> t);
142  else return a.mant > 0 ;
143 }
144 
146  int t= a.exp - b.exp;
147  if (t <-31) return b;
148  else if (t < 0) return av_normalize_sf(av_normalize1_sf((SoftFloat){ b.mant + (a.mant >> (-t)), b.exp}));
149  else if (t < 32) return av_normalize_sf(av_normalize1_sf((SoftFloat){ a.mant + (b.mant >> t ), a.exp}));
150  else return a;
151 }
152 
154  return av_add_sf(a, (SoftFloat){ -b.mant, b.exp});
155 }
156 
157 //FIXME log, exp, pow
158 
159 /**
160  * Converts a mantisse and exponent to a SoftFloat.
161  * This converts a fixed point value v with frac_bits fractional bits to a
162  * SoftFloat.
163  * @returns a SoftFloat with value v * 2^-frac_bits
164  */
165 static inline av_const SoftFloat av_int2sf(int v, int frac_bits){
166  int exp_offset = 0;
167  if(v <= INT_MIN + 1){
168  exp_offset = 1;
169  v>>=1;
170  }
171  return av_normalize_sf(av_normalize1_sf((SoftFloat){v, ONE_BITS + 1 - frac_bits + exp_offset}));
172 }
173 
174 /**
175  * Rounding is to -inf.
176  */
177 static inline av_const int av_sf2int(SoftFloat v, int frac_bits){
178  v.exp += frac_bits - (ONE_BITS + 1);
179  if(v.exp >= 0) return v.mant << v.exp ;
180  else return v.mant >>(-v.exp);
181 }
182 
183 /**
184  * Rounding-to-nearest used.
185  */
187 {
188  int tabIndex, rem;
189 
190  if (val.mant == 0)
191  val.exp = MIN_EXP;
192  else if (val.mant < 0)
193  abort();
194  else
195  {
196  tabIndex = (val.mant - 0x20000000) >> 20;
197 
198  rem = val.mant & 0xFFFFF;
199  val.mant = (int)(((int64_t)av_sqrttbl_sf[tabIndex] * (0x100000 - rem) +
200  (int64_t)av_sqrttbl_sf[tabIndex + 1] * rem +
201  0x80000) >> 20);
202  val.mant = (int)(((int64_t)av_sqr_exp_multbl_sf[val.exp & 1] * val.mant +
203  0x10000000) >> 29);
204 
205  if (val.mant < 0x40000000)
206  val.exp -= 2;
207  else
208  val.mant >>= 1;
209 
210  val.exp = (val.exp >> 1) + 1;
211  }
212 
213  return val;
214 }
215 
216 /**
217  * Rounding-to-nearest used.
218  */
219 static av_unused void av_sincos_sf(int a, int *s, int *c)
220 {
221  int idx, sign;
222  int sv, cv;
223  int st, ct;
224 
225  idx = a >> 26;
226  sign = (int32_t)((unsigned)idx << 27) >> 31;
227  cv = av_costbl_1_sf[idx & 0xf];
228  cv = (cv ^ sign) - sign;
229 
230  idx -= 8;
231  sign = (int32_t)((unsigned)idx << 27) >> 31;
232  sv = av_costbl_1_sf[idx & 0xf];
233  sv = (sv ^ sign) - sign;
234 
235  idx = a >> 21;
236  ct = av_costbl_2_sf[idx & 0x1f];
237  st = av_sintbl_2_sf[idx & 0x1f];
238 
239  idx = (int)(((int64_t)cv * ct - (int64_t)sv * st + 0x20000000) >> 30);
240 
241  sv = (int)(((int64_t)cv * st + (int64_t)sv * ct + 0x20000000) >> 30);
242 
243  cv = idx;
244 
245  idx = a >> 16;
246  ct = av_costbl_3_sf[idx & 0x1f];
247  st = av_sintbl_3_sf[idx & 0x1f];
248 
249  idx = (int)(((int64_t)cv * ct - (int64_t)sv * st + 0x20000000) >> 30);
250 
251  sv = (int)(((int64_t)cv * st + (int64_t)sv * ct + 0x20000000) >> 30);
252  cv = idx;
253 
254  idx = a >> 11;
255 
256  ct = (int)(((int64_t)av_costbl_4_sf[idx & 0x1f] * (0x800 - (a & 0x7ff)) +
257  (int64_t)av_costbl_4_sf[(idx & 0x1f)+1]*(a & 0x7ff) +
258  0x400) >> 11);
259  st = (int)(((int64_t)av_sintbl_4_sf[idx & 0x1f] * (0x800 - (a & 0x7ff)) +
260  (int64_t)av_sintbl_4_sf[(idx & 0x1f) + 1] * (a & 0x7ff) +
261  0x400) >> 11);
262 
263  *c = (int)(((int64_t)cv * ct + (int64_t)sv * st + 0x20000000) >> 30);
264 
265  *s = (int)(((int64_t)cv * st + (int64_t)sv * ct + 0x20000000) >> 30);
266 }
267 
268 #endif /* AVUTIL_SOFTFLOAT_H */
#define av_const
Definition: attributes.h:68
static av_always_inline SoftFloat av_sqrt_sf(SoftFloat val)
Rounding-to-nearest used.
Definition: softfloat.h:186
const char const char void * val
Definition: avisynth_c.h:634
float v
const char * s
Definition: avisynth_c.h:631
#define ONE_BITS
Definition: softfloat.h:32
static const int32_t av_costbl_4_sf[33]
static const SoftFloat FLOAT_05
Definition: softfloat.h:40
else temp
Definition: vf_mcdeint.c:257
static av_const SoftFloat av_div_sf(SoftFloat a, SoftFloat b)
b has to be normalized and not zero.
Definition: softfloat.h:112
const char * b
Definition: vf_curves.c:109
static const int32_t av_sintbl_3_sf[32]
static const SoftFloat FLOAT_0
Definition: softfloat.h:39
static av_const double av_sf2double(SoftFloat v)
Definition: softfloat.h:48
#define av_assert2(cond)
assert() equivalent, that does lie in speed critical code.
Definition: avassert.h:63
int32_t mant
Definition: softfloat.h:35
static const SoftFloat FLOAT_100000
Definition: softfloat.h:44
#define U(x)
Definition: vp56_arith.h:37
static av_const SoftFloat av_normalize_sf(SoftFloat a)
Definition: softfloat.h:54
static const SoftFloat FLOAT_1
Definition: softfloat.h:41
static const SoftFloat FLOAT_0999999
Definition: softfloat.h:45
simple assert() macros that are a bit more flexible than ISO C assert().
static av_unused void av_sincos_sf(int a, int *s, int *c)
Rounding-to-nearest used.
Definition: softfloat.h:219
int32_t
static av_const int av_cmp_sf(SoftFloat a, SoftFloat b)
Definition: softfloat.h:128
#define FFABS(a)
Absolute value, Note, INT_MIN / INT64_MIN result in undefined behavior as they are not representable ...
Definition: common.h:68
static av_const int av_gt_sf(SoftFloat a, SoftFloat b)
Definition: softfloat.h:136
#define av_log2
Definition: intmath.h:100
static av_const SoftFloat av_normalize1_sf(SoftFloat a)
Definition: softfloat.h:76
static const int32_t av_sqrttbl_sf[512+1]
static av_const int av_sf2int(SoftFloat v, int frac_bits)
Rounding is to -inf.
Definition: softfloat.h:177
static const int32_t av_costbl_2_sf[32]
static const int32_t av_costbl_1_sf[16]
#define MIN_EXP
Definition: softfloat.h:30
static const int32_t av_sintbl_2_sf[32]
static av_const SoftFloat av_sub_sf(SoftFloat a, SoftFloat b)
Definition: softfloat.h:153
static av_const SoftFloat av_add_sf(SoftFloat a, SoftFloat b)
Definition: softfloat.h:145
static const int32_t av_sqr_exp_multbl_sf[2]
common internal and external API header
static const SoftFloat FLOAT_1584893192
Definition: softfloat.h:43
static av_const SoftFloat av_mul_sf(SoftFloat a, SoftFloat b)
Definition: softfloat.h:98
static double c[64]
int32_t exp
Definition: softfloat.h:36
static const SoftFloat FLOAT_EPSILON
Definition: softfloat.h:42
static const int32_t av_sintbl_4_sf[33]
static const SoftFloat FLOAT_MIN
Definition: softfloat.h:46
static const int32_t av_costbl_3_sf[32]
static av_const SoftFloat av_int2sf(int v, int frac_bits)
Converts a mantisse and exponent to a SoftFloat.
Definition: softfloat.h:165
#define av_always_inline
Definition: attributes.h:37
#define av_unused
Definition: attributes.h:118