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.mant>>t, a.exp+t};
72 int t= (a.mant + 0x40000000U)>>31;
73 return (SoftFloat){a.mant>>t, a.exp+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((SoftFloat){a.mant, a.exp - 1});
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_normalize_sf(av_normalize1_sf((SoftFloat){ b.mant + (a.mant >> (-t)), b.exp}));
109 else if (t < 32) return av_normalize_sf(av_normalize1_sf((SoftFloat){ a.mant + (b.mant >> t ), a.exp}));
113 static inline av_const SoftFloat av_sub_sf(SoftFloat a, SoftFloat b){
114 return av_add_sf(a, (SoftFloat){ -b.mant, b.exp});
117 //FIXME sqrt, log, exp, pow, sin, cos
120 * Converts a mantisse and exponent to a SoftFloat
121 * @returns a SoftFloat with value v * 2^frac_bits
123 static inline av_const SoftFloat av_int2sf(int v, int frac_bits){
124 return av_normalize_sf((SoftFloat){v, ONE_BITS + 1 - frac_bits});
128 * Rounding is to -inf.
130 static inline av_const int av_sf2int(SoftFloat v, int frac_bits){
131 v.exp += frac_bits - (ONE_BITS + 1);
132 if(v.exp >= 0) return v.mant << v.exp ;
133 else return v.mant >>(-v.exp);
136 #endif /* AVUTIL_SOFTFLOAT_H */