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 Libav. 7 * 8 * Libav 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 * Libav 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 Libav; 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 25 * portable IEEE float/double read/write functions 26 */ 27 28#include <stdint.h> 29#include "mathematics.h" 30#include "intfloat_readwrite.h" 31 32double av_int2dbl(int64_t v){ 33 if((uint64_t)v+v > 0xFFEULL<<52) 34 return NAN; 35 return ldexp(((v&((1LL<<52)-1)) + (1LL<<52)) * (v>>63|1), (v>>52&0x7FF)-1075); 36} 37 38float av_int2flt(int32_t v){ 39 if((uint32_t)v+v > 0xFF000000U) 40 return NAN; 41 return ldexp(((v&0x7FFFFF) + (1<<23)) * (v>>31|1), (v>>23&0xFF)-150); 42} 43 44double av_ext2dbl(const AVExtFloat ext){ 45 uint64_t m = 0; 46 int e, i; 47 48 for (i = 0; i < 8; i++) 49 m = (m<<8) + ext.mantissa[i]; 50 e = (((int)ext.exponent[0]&0x7f)<<8) | ext.exponent[1]; 51 if (e == 0x7fff && m) 52 return NAN; 53 e -= 16383 + 63; /* In IEEE 80 bits, the whole (i.e. 1.xxxx) 54 * mantissa bit is written as opposed to the 55 * single and double precision formats. */ 56 if (ext.exponent[0]&0x80) 57 m= -m; 58 return ldexp(m, e); 59} 60 61int64_t av_dbl2int(double d){ 62 int e; 63 if ( !d) return 0; 64 else if(d-d) return 0x7FF0000000000000LL + ((int64_t)(d<0)<<63) + (d!=d); 65 d= frexp(d, &e); 66 return (int64_t)(d<0)<<63 | (e+1022LL)<<52 | (int64_t)((fabs(d)-0.5)*(1LL<<53)); 67} 68 69int32_t av_flt2int(float d){ 70 int e; 71 if ( !d) return 0; 72 else if(d-d) return 0x7F800000 + ((d<0)<<31) + (d!=d); 73 d= frexp(d, &e); 74 return (d<0)<<31 | (e+126)<<23 | (int64_t)((fabs(d)-0.5)*(1<<24)); 75} 76 77AVExtFloat av_dbl2ext(double d){ 78 struct AVExtFloat ext= {{0}}; 79 int e, i; double f; uint64_t m; 80 81 f = fabs(frexp(d, &e)); 82 if (f >= 0.5 && f < 1) { 83 e += 16382; 84 ext.exponent[0] = e>>8; 85 ext.exponent[1] = e; 86 m = (uint64_t)ldexp(f, 64); 87 for (i=0; i < 8; i++) 88 ext.mantissa[i] = m>>(56-(i<<3)); 89 } else if (f != 0.0) { 90 ext.exponent[0] = 0x7f; ext.exponent[1] = 0xff; 91 if (f != INFINITY) 92 ext.mantissa[0] = ~0; 93 } 94 if (d < 0) 95 ext.exponent[0] |= 0x80; 96 return ext; 97} 98 99