2 * Copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
4 * This file is part of FFmpeg.
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.
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.
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
21 #ifndef AVUTIL_SOFTFLOAT_H
22 #define AVUTIL_SOFTFLOAT_H
33 typedef struct SoftFloat
{
38 static av_const SoftFloat
av_normalize_sf(SoftFloat a
){
41 while((a
.mant
+ 0x20000000U
)<0x40000000U
){
46 int s
=ONE_BITS
+ 1 - av_log2(a
.mant
^ (a
.mant
<<1));
60 static inline av_const SoftFloat
av_normalize1_sf(SoftFloat a
){
62 if((int32_t)(a
.mant
+ 0x40000000U
) < 0){
66 av_assert2(a
.mant
< 0x40000000 && a
.mant
> -0x40000000);
69 int t
= a
.mant
+ 0x40000000 < 0;
70 return (SoftFloat
){a
.exp
+t
, a
.mant
>>t
};
72 int t
= (a
.mant
+ 0x40000000U
)>>31;
73 return (SoftFloat
){a
.exp
+t
, a
.mant
>>t
};
78 * @return Will not be more denormalized than a+b. So if either input is
79 * normalized, then the output will not be worse then the other input.
80 * If both are normalized, then the output will be normalized.
82 static inline av_const SoftFloat
av_mul_sf(SoftFloat a
, SoftFloat b
){
84 av_assert2((int32_t)((a
.mant
* (int64_t)b
.mant
) >> ONE_BITS
) == (a
.mant
* (int64_t)b
.mant
) >> ONE_BITS
);
85 a
.mant
= (a
.mant
* (int64_t)b
.mant
) >> ONE_BITS
;
86 return av_normalize1_sf(a
);
90 * b has to be normalized and not zero.
91 * @return Will not be more denormalized than a.
93 static av_const SoftFloat
av_div_sf(SoftFloat a
, SoftFloat b
){
95 a
.mant
= ((int64_t)a
.mant
<<(ONE_BITS
+1)) / b
.mant
;
96 return av_normalize1_sf(a
);
99 static inline av_const
int av_cmp_sf(SoftFloat a
, SoftFloat b
){
100 int t
= a
.exp
- b
.exp
;
101 if(t
<0) return (a
.mant
>> (-t
)) - b
.mant
;
102 else return a
.mant
- (b
.mant
>> t
);
105 static inline av_const SoftFloat
av_add_sf(SoftFloat a
, SoftFloat b
){
106 int t
= a
.exp
- b
.exp
;
107 if (t
<-31) return b
;
108 else if (t
< 0) return av_normalize1_sf((SoftFloat
){b
.exp
, b
.mant
+ (a
.mant
>> (-t
))});
109 else if (t
< 32) return av_normalize1_sf((SoftFloat
){a
.exp
, a
.mant
+ (b
.mant
>> t
)});
113 static inline av_const SoftFloat
av_sub_sf(SoftFloat a
, SoftFloat b
){
114 return av_add_sf(a
, (SoftFloat
){b
.exp
, -b
.mant
});
117 //FIXME sqrt, log, exp, pow, sin, cos
119 static inline av_const SoftFloat
av_int2sf(int v
, int frac_bits
){
120 return av_normalize_sf((SoftFloat
){ONE_BITS
-frac_bits
, v
});
124 * Rounding is to -inf.
126 static inline av_const
int av_sf2int(SoftFloat v
, int frac_bits
){
127 v
.exp
+= frac_bits
- ONE_BITS
;
128 if(v
.exp
>= 0) return v
.mant
<< v
.exp
;
129 else return v
.mant
>>(-v
.exp
);
132 #endif /* AVUTIL_SOFTFLOAT_H */