1129198Scognet/* $NetBSD: ieee754.h,v 1.4 2003/10/27 02:30:26 simonb Exp $ */ 2129198Scognet 3139735Simp/*- 4129198Scognet * Copyright (c) 1992, 1993 5129198Scognet * The Regents of the University of California. All rights reserved. 6129198Scognet * 7129198Scognet * This software was developed by the Computer Systems Engineering group 8129198Scognet * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and 9129198Scognet * contributed to Berkeley. 10129198Scognet * 11129198Scognet * All advertising materials mentioning features or use of this software 12129198Scognet * must display the following acknowledgement: 13129198Scognet * This product includes software developed by the University of 14129198Scognet * California, Lawrence Berkeley Laboratory. 15129198Scognet * 16129198Scognet * Redistribution and use in source and binary forms, with or without 17129198Scognet * modification, are permitted provided that the following conditions 18129198Scognet * are met: 19129198Scognet * 1. Redistributions of source code must retain the above copyright 20129198Scognet * notice, this list of conditions and the following disclaimer. 21129198Scognet * 2. Redistributions in binary form must reproduce the above copyright 22129198Scognet * notice, this list of conditions and the following disclaimer in the 23129198Scognet * documentation and/or other materials provided with the distribution. 24129198Scognet * 3. Neither the name of the University nor the names of its contributors 25129198Scognet * may be used to endorse or promote products derived from this software 26129198Scognet * without specific prior written permission. 27129198Scognet * 28129198Scognet * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 29129198Scognet * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 30129198Scognet * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 31129198Scognet * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 32129198Scognet * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 33129198Scognet * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 34129198Scognet * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 35129198Scognet * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 36129198Scognet * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 37129198Scognet * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 38129198Scognet * SUCH DAMAGE. 39129198Scognet * 40129198Scognet * @(#)ieee.h 8.1 (Berkeley) 6/11/93 41129198Scognet * 42129198Scognet * $FreeBSD$ 43129198Scognet * 44129198Scognet */ 45129198Scognet 46129198Scognet/* 47129198Scognet * NOTICE: This is not a standalone file. To use it, #include it in 48129198Scognet * your port's ieee.h header. 49129198Scognet */ 50129198Scognet 51129198Scognet#include <machine/endian.h> 52129198Scognet 53129198Scognet/* 54129198Scognet * <sys/ieee754.h> defines the layout of IEEE 754 floating point types. 55129198Scognet * Only single-precision and double-precision types are defined here; 56129198Scognet * extended types, if available, are defined in the machine-dependent 57129198Scognet * header. 58129198Scognet */ 59129198Scognet 60129198Scognet/* 61129198Scognet * Define the number of bits in each fraction and exponent. 62129198Scognet * 63129198Scognet * k k+1 64129198Scognet * Note that 1.0 x 2 == 0.1 x 2 and that denorms are represented 65129198Scognet * 66129198Scognet * (-exp_bias+1) 67129198Scognet * as fractions that look like 0.fffff x 2 . This means that 68129198Scognet * 69129198Scognet * -126 70129198Scognet * the number 0.10000 x 2 , for instance, is the same as the normalized 71129198Scognet * 72129198Scognet * -127 -128 73129198Scognet * float 1.0 x 2 . Thus, to represent 2 , we need one leading zero 74129198Scognet * 75129198Scognet * -129 76129198Scognet * in the fraction; to represent 2 , we need two, and so on. This 77129198Scognet * 78129198Scognet * (-exp_bias-fracbits+1) 79129198Scognet * implies that the smallest denormalized number is 2 80129198Scognet * 81129198Scognet * for whichever format we are talking about: for single precision, for 82129198Scognet * 83129198Scognet * -126 -149 84129198Scognet * instance, we get .00000000000000000000001 x 2 , or 1.0 x 2 , and 85129198Scognet * 86129198Scognet * -149 == -127 - 23 + 1. 87129198Scognet */ 88129198Scognet#define SNG_EXPBITS 8 89129198Scognet#define SNG_FRACBITS 23 90129198Scognet 91129198Scognet#define DBL_EXPBITS 11 92129198Scognet#define DBL_FRACBITS 52 93129198Scognet 94255361Sandrew#if defined(__VFP_FP__) || defined(__ARM_EABI__) 95186461Smarcel#define _IEEE_WORD_ORDER _BYTE_ORDER 96186461Smarcel#else 97186461Smarcel#define _IEEE_WORD_ORDER _BIG_ENDIAN 98186461Smarcel#endif 99186461Smarcel 100129198Scognetstruct ieee_single { 101129198Scognet#if _BYTE_ORDER == _BIG_ENDIAN 102129198Scognet u_int sng_sign:1; 103129198Scognet u_int sng_exp:8; 104129198Scognet u_int sng_frac:23; 105129198Scognet#else 106129198Scognet u_int sng_frac:23; 107129198Scognet u_int sng_exp:8; 108129198Scognet u_int sng_sign:1; 109129198Scognet#endif 110129198Scognet}; 111129198Scognet 112129198Scognetstruct ieee_double { 113129198Scognet#if _BYTE_ORDER == _BIG_ENDIAN 114129198Scognet u_int dbl_sign:1; 115129198Scognet u_int dbl_exp:11; 116129198Scognet u_int dbl_frach:20; 117129198Scognet u_int dbl_fracl; 118129198Scognet#else 119186461Smarcel#if _IEEE_WORD_ORDER == _LITTLE_ENDIAN 120129198Scognet u_int dbl_fracl; 121186461Smarcel#endif 122129198Scognet u_int dbl_frach:20; 123129198Scognet u_int dbl_exp:11; 124129198Scognet u_int dbl_sign:1; 125186461Smarcel#if _IEEE_WORD_ORDER == _BIG_ENDIAN 126186461Smarcel u_int dbl_fracl; 127129198Scognet#endif 128236992Simp#endif 129129198Scognet}; 130129198Scognet 131129198Scognet/* 132129198Scognet * Floats whose exponent is in [1..INFNAN) (of whatever type) are 133129198Scognet * `normal'. Floats whose exponent is INFNAN are either Inf or NaN. 134129198Scognet * Floats whose exponent is zero are either zero (iff all fraction 135129198Scognet * bits are zero) or subnormal values. 136129198Scognet * 137129198Scognet * A NaN is a `signalling NaN' if its QUIETNAN bit is clear in its 138129198Scognet * high fraction; if the bit is set, it is a `quiet NaN'. 139129198Scognet */ 140129198Scognet#define SNG_EXP_INFNAN 255 141129198Scognet#define DBL_EXP_INFNAN 2047 142129198Scognet 143129198Scognet#if 0 144129198Scognet#define SNG_QUIETNAN (1 << 22) 145129198Scognet#define DBL_QUIETNAN (1 << 19) 146129198Scognet#endif 147129198Scognet 148129198Scognet/* 149129198Scognet * Exponent biases. 150129198Scognet */ 151129198Scognet#define SNG_EXP_BIAS 127 152129198Scognet#define DBL_EXP_BIAS 1023 153129198Scognet 154129198Scognet/* 155129198Scognet * Convenience data structures. 156129198Scognet */ 157129198Scognetunion ieee_single_u { 158129198Scognet float sngu_f; 159129198Scognet struct ieee_single sngu_sng; 160129198Scognet}; 161129198Scognet 162129198Scognetunion ieee_double_u { 163129198Scognet double dblu_d; 164129198Scognet struct ieee_double dblu_dbl; 165129198Scognet}; 166