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
26 typedef struct SoftFloat{
31 static SoftFloat av_normalize_sf(SoftFloat a){
34 while((a.mant + 0x20000000U)<0x40000000U){
39 int s=ONE_BITS + 1 - av_log2(a.mant ^ (a.mant<<1));
53 static inline SoftFloat av_normalize1_sf(SoftFloat a){
55 if(a.mant + 0x40000000 < 0){
61 int t= a.mant + 0x40000000 < 0;
62 return (SoftFloat){a.exp+t, a.mant>>t};
64 int t= (a.mant + 0x40000000U)>>31;
65 return (SoftFloat){a.exp+t, a.mant>>t};
71 * @return will not be more denormalized then a+b, so if either input is
72 * normalized then the output wont be worse then the other input
73 * if both are normalized then the output will be normalized
75 static inline SoftFloat av_mul_sf(SoftFloat a, SoftFloat b){
77 a.mant = (a.mant * (int64_t)b.mant) >> ONE_BITS;
78 return av_normalize1_sf(a);
83 * b has to be normalized and not zero
84 * @return will not be more denormalized then a
86 static SoftFloat av_div_sf(SoftFloat a, SoftFloat b){
88 a.mant = ((int64_t)a.mant<<(ONE_BITS+1)) / b.mant;
89 return av_normalize1_sf(a);
92 static inline int av_cmp_sf(SoftFloat a, SoftFloat b){
94 if(t<0) return (a.mant >> (-t)) - b.mant ;
95 else return a.mant - (b.mant >> t);
98 static inline SoftFloat av_add_sf(SoftFloat a, SoftFloat b){
100 if(t<0) return av_normalize1_sf((SoftFloat){b.exp, b.mant + (a.mant >> (-t))});
101 else return av_normalize1_sf((SoftFloat){a.exp, a.mant + (b.mant >> t )});
104 static inline SoftFloat av_sub_sf(SoftFloat a, SoftFloat b){
105 return av_add_sf(a, (SoftFloat){b.exp, -b.mant});
108 //FIXME sqrt, log, exp, pow, sin, cos
110 static inline SoftFloat av_int2sf(int v, int frac_bits){
111 return av_normalize_sf((SoftFloat){ONE_BITS-frac_bits, v});
116 * rounding is to -inf
118 static inline int av_sf2int(SoftFloat v, int frac_bits){
119 v.exp += frac_bits - ONE_BITS;
120 if(v.exp >= 0) return v.mant << v.exp ;
121 else return v.mant >>(-v.exp);