/* * portable IEEE float/double read/write functions * * Copyright (c) 2005 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 */ /** * @file libavutil/intfloat_readwrite.c * portable IEEE float/double read/write functions */ #include "common.h" #include "intfloat_readwrite.h" double av_int2dbl(int64_t v){ if(v+v > 0xFFEULL<<52) return 0.0/0.0; return ldexp(((v&((1LL<<52)-1)) + (1LL<<52)) * (v>>63|1), (v>>52&0x7FF)-1075); } float av_int2flt(int32_t v){ if(v+v > 0xFF000000U) return 0.0/0.0; return ldexp(((v&0x7FFFFF) + (1<<23)) * (v>>31|1), (v>>23&0xFF)-150); } double av_ext2dbl(const AVExtFloat ext){ uint64_t m = 0; int e, i; for (i = 0; i < 8; i++) m = (m<<8) + ext.mantissa[i]; e = (((int)ext.exponent[0]&0x7f)<<8) | ext.exponent[1]; if (e == 0x7fff && m) return 0.0/0.0; e -= 16383 + 63; /* In IEEE 80 bits, the whole (i.e. 1.xxxx) * mantissa bit is written as opposed to the * single and double precision formats. */ if (ext.exponent[0]&0x80) m= -m; return ldexp(m, e); } int64_t av_dbl2int(double d){ int e; if ( !d) return 0; else if(d-d) return 0x7FF0000000000000LL + ((int64_t)(d<0)<<63) + (d!=d); d= frexp(d, &e); return (int64_t)(d<0)<<63 | (e+1022LL)<<52 | (int64_t)((fabs(d)-0.5)*(1LL<<53)); } int32_t av_flt2int(float d){ int e; if ( !d) return 0; else if(d-d) return 0x7F800000 + ((d<0)<<31) + (d!=d); d= frexp(d, &e); return (d<0)<<31 | (e+126)<<23 | (int64_t)((fabs(d)-0.5)*(1<<24)); } AVExtFloat av_dbl2ext(double d){ struct AVExtFloat ext= {{0}}; int e, i; double f; uint64_t m; f = fabs(frexp(d, &e)); if (f >= 0.5 && f < 1) { e += 16382; ext.exponent[0] = e>>8; ext.exponent[1] = e; m = (uint64_t)ldexp(f, 64); for (i=0; i < 8; i++) ext.mantissa[i] = m>>(56-(i<<3)); } else if (f != 0.0) { ext.exponent[0] = 0x7f; ext.exponent[1] = 0xff; if (f != 1/0.0) ext.mantissa[0] = ~0; } if (d < 0) ext.exponent[0] |= 0x80; return ext; }