/* * Copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at> * * This file is part of FFmpeg. * * FFmpeg is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * FFmpeg is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA * */ #define MIN_EXP -126 #define MAX_EXP 126 #define ONE_BITS 29 typedef struct SoftFloat{ int32_t exp; int32_t mant; }SoftFloat; static SoftFloat av_normalize_sf(SoftFloat a){ if(a.mant){ #if 1 while((a.mant + 0x20000000U)<0x40000000U){ a.mant += a.mant; a.exp -= 1; } #else int s=ONE_BITS + 1 - av_log2(a.mant ^ (a.mant<<1)); a.exp -= s; a.mant <<= s; #endif if(a.exp < MIN_EXP){ a.exp = MIN_EXP; a.mant= 0; } }else{ a.exp= MIN_EXP; } return a; } static inline SoftFloat av_normalize1_sf(SoftFloat a){ #if 1 if(a.mant + 0x40000000 < 0){ a.exp++; a.mant>>=1; } return a; #elif 1 int t= a.mant + 0x40000000 < 0; return (SoftFloat){a.exp+t, a.mant>>t}; #else int t= (a.mant + 0x40000000U)>>31; return (SoftFloat){a.exp+t, a.mant>>t}; #endif } /** * * @return will not be more denormalized then a+b, so if either input is * normalized then the output wont be worse then the other input * if both are normalized then the output will be normalized */ static inline SoftFloat av_mul_sf(SoftFloat a, SoftFloat b){ a.exp += b.exp; a.mant = (a.mant * (int64_t)b.mant) >> ONE_BITS; return av_normalize1_sf(a); } /** * * b has to be normalized and not zero * @return will not be more denormalized then a */ static SoftFloat av_div_sf(SoftFloat a, SoftFloat b){ a.exp -= b.exp+1; a.mant = ((int64_t)a.mant<<(ONE_BITS+1)) / b.mant; return av_normalize1_sf(a); } static inline int av_cmp_sf(SoftFloat a, SoftFloat b){ int t= a.exp - b.exp; if(t<0) return (a.mant >> (-t)) - b.mant ; else return a.mant - (b.mant >> t); } static inline SoftFloat av_add_sf(SoftFloat a, SoftFloat b){ int t= a.exp - b.exp; if(t<0) return av_normalize1_sf((SoftFloat){b.exp, b.mant + (a.mant >> (-t))}); else return av_normalize1_sf((SoftFloat){a.exp, a.mant + (b.mant >> t )}); } static inline SoftFloat av_sub_sf(SoftFloat a, SoftFloat b){ return av_add_sf(a, (SoftFloat){b.exp, -b.mant}); } //FIXME sqrt, log, exp, pow, sin, cos static inline SoftFloat av_int2sf(int v, int frac_bits){ return av_normalize_sf((SoftFloat){ONE_BITS-frac_bits, v}); } /** * * rounding is to -inf */ static inline int av_sf2int(SoftFloat v, int frac_bits){ v.exp += frac_bits - ONE_BITS; if(v.exp >= 0) return v.mant << v.exp ; else return v.mant >>(-v.exp); }