1/* 2 * portable IEEE float/double read/write functions 3 * 4 * Copyright (c) 2005 Michael Niedermayer <michaelni@gmx.at> 5 * 6 * This file is part of FFmpeg. 7 * 8 * FFmpeg is free software; you can redistribute it and/or 9 * modify it under the terms of the GNU Lesser General Public 10 * License as published by the Free Software Foundation; either 11 * version 2.1 of the License, or (at your option) any later version. 12 * 13 * FFmpeg is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 16 * Lesser General Public License for more details. 17 * 18 * You should have received a copy of the GNU Lesser General Public 19 * License along with FFmpeg; if not, write to the Free Software 20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 21 */ 22 23/** 24 * @file libavutil/intfloat_readwrite.c 25 * portable IEEE float/double read/write functions 26 */ 27 28#include "common.h" 29#include "intfloat_readwrite.h" 30 31double av_int2dbl(int64_t v){ 32 if(v+v > 0xFFEULL<<52) 33 return 0.0/0.0; 34 return ldexp(((v&((1LL<<52)-1)) + (1LL<<52)) * (v>>63|1), (v>>52&0x7FF)-1075); 35} 36 37float av_int2flt(int32_t v){ 38 if(v+v > 0xFF000000U) 39 return 0.0/0.0; 40 return ldexp(((v&0x7FFFFF) + (1<<23)) * (v>>31|1), (v>>23&0xFF)-150); 41} 42 43double av_ext2dbl(const AVExtFloat ext){ 44 uint64_t m = 0; 45 int e, i; 46 47 for (i = 0; i < 8; i++) 48 m = (m<<8) + ext.mantissa[i]; 49 e = (((int)ext.exponent[0]&0x7f)<<8) | ext.exponent[1]; 50 if (e == 0x7fff && m) 51 return 0.0/0.0; 52 e -= 16383 + 63; /* In IEEE 80 bits, the whole (i.e. 1.xxxx) 53 * mantissa bit is written as opposed to the 54 * single and double precision formats. */ 55 if (ext.exponent[0]&0x80) 56 m= -m; 57 return ldexp(m, e); 58} 59 60int64_t av_dbl2int(double d){ 61 int e; 62 if ( !d) return 0; 63 else if(d-d) return 0x7FF0000000000000LL + ((int64_t)(d<0)<<63) + (d!=d); 64 d= frexp(d, &e); 65 return (int64_t)(d<0)<<63 | (e+1022LL)<<52 | (int64_t)((fabs(d)-0.5)*(1LL<<53)); 66} 67 68int32_t av_flt2int(float d){ 69 int e; 70 if ( !d) return 0; 71 else if(d-d) return 0x7F800000 + ((d<0)<<31) + (d!=d); 72 d= frexp(d, &e); 73 return (d<0)<<31 | (e+126)<<23 | (int64_t)((fabs(d)-0.5)*(1<<24)); 74} 75 76AVExtFloat av_dbl2ext(double d){ 77 struct AVExtFloat ext= {{0}}; 78 int e, i; double f; uint64_t m; 79 80 f = fabs(frexp(d, &e)); 81 if (f >= 0.5 && f < 1) { 82 e += 16382; 83 ext.exponent[0] = e>>8; 84 ext.exponent[1] = e; 85 m = (uint64_t)ldexp(f, 64); 86 for (i=0; i < 8; i++) 87 ext.mantissa[i] = m>>(56-(i<<3)); 88 } else if (f != 0.0) { 89 ext.exponent[0] = 0x7f; ext.exponent[1] = 0xff; 90 if (f != 1/0.0) 91 ext.mantissa[0] = ~0; 92 } 93 if (d < 0) 94 ext.exponent[0] |= 0x80; 95 return ext; 96} 97 98