ieee.h revision 86551
186551Sjake/* 286551Sjake * Copyright (c) 1992, 1993 386551Sjake * The Regents of the University of California. All rights reserved. 486551Sjake * 586551Sjake * This software was developed by the Computer Systems Engineering group 686551Sjake * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and 786551Sjake * contributed to Berkeley. 886551Sjake * 986551Sjake * All advertising materials mentioning features or use of this software 1086551Sjake * must display the following acknowledgement: 1186551Sjake * This product includes software developed by the University of 1286551Sjake * California, Lawrence Berkeley Laboratory. 1386551Sjake * 1486551Sjake * Redistribution and use in source and binary forms, with or without 1586551Sjake * modification, are permitted provided that the following conditions 1686551Sjake * are met: 1786551Sjake * 1. Redistributions of source code must retain the above copyright 1886551Sjake * notice, this list of conditions and the following disclaimer. 1986551Sjake * 2. Redistributions in binary form must reproduce the above copyright 2086551Sjake * notice, this list of conditions and the following disclaimer in the 2186551Sjake * documentation and/or other materials provided with the distribution. 2286551Sjake * 3. All advertising materials mentioning features or use of this software 2386551Sjake * must display the following acknowledgement: 2486551Sjake * This product includes software developed by the University of 2586551Sjake * California, Berkeley and its contributors. 2686551Sjake * 4. Neither the name of the University nor the names of its contributors 2786551Sjake * may be used to endorse or promote products derived from this software 2886551Sjake * without specific prior written permission. 2986551Sjake * 3086551Sjake * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 3186551Sjake * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 3286551Sjake * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 3386551Sjake * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 3486551Sjake * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 3586551Sjake * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 3686551Sjake * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 3786551Sjake * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 3886551Sjake * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 3986551Sjake * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 4086551Sjake * SUCH DAMAGE. 4186551Sjake * 4286551Sjake * @(#)ieee.h 8.1 (Berkeley) 6/11/93 4386551Sjake * from: NetBSD: ieee.h,v 1.1.1.1 1998/06/20 04:58:51 eeh Exp 4486551Sjake * $FreeBSD: head/sys/sparc64/include/ieee.h 86551 2001-11-18 17:56:46Z jake $ 4586551Sjake */ 4686551Sjake 4786551Sjake#ifndef _MACHINE_IEEE_H_ 4886551Sjake#define _MACHINE_IEEE_H_ 4986551Sjake 5086551Sjake/* 5186551Sjake * ieee.h defines the machine-dependent layout of the machine's IEEE 5286551Sjake * floating point. It does *not* define (yet?) any of the rounding 5386551Sjake * mode bits, exceptions, and so forth. 5486551Sjake */ 5586551Sjake 5686551Sjake/* 5786551Sjake * Define the number of bits in each fraction and exponent. 5886551Sjake * 5986551Sjake * k k+1 6086551Sjake * Note that 1.0 x 2 == 0.1 x 2 and that denorms are represented 6186551Sjake * 6286551Sjake * (-exp_bias+1) 6386551Sjake * as fractions that look like 0.fffff x 2 . This means that 6486551Sjake * 6586551Sjake * -126 6686551Sjake * the number 0.10000 x 2 , for instance, is the same as the normalized 6786551Sjake * 6886551Sjake * -127 -128 6986551Sjake * float 1.0 x 2 . Thus, to represent 2 , we need one leading zero 7086551Sjake * 7186551Sjake * -129 7286551Sjake * in the fraction; to represent 2 , we need two, and so on. This 7386551Sjake * 7486551Sjake * (-exp_bias-fracbits+1) 7586551Sjake * implies that the smallest denormalized number is 2 7686551Sjake * 7786551Sjake * for whichever format we are talking about: for single precision, for 7886551Sjake * 7986551Sjake * -126 -149 8086551Sjake * instance, we get .00000000000000000000001 x 2 , or 1.0 x 2 , and 8186551Sjake * 8286551Sjake * -149 == -127 - 23 + 1. 8386551Sjake */ 8486551Sjake#define SNG_EXPBITS 8 8586551Sjake#define SNG_FRACBITS 23 8686551Sjake 8786551Sjake#define DBL_EXPBITS 11 8886551Sjake#define DBL_FRACBITS 52 8986551Sjake 9086551Sjake#ifdef notyet 9186551Sjake#define E80_EXPBITS 15 9286551Sjake#define E80_FRACBITS 64 9386551Sjake#endif 9486551Sjake 9586551Sjake#define EXT_EXPBITS 15 9686551Sjake#define EXT_FRACBITS 112 9786551Sjake 9886551Sjakestruct ieee_single { 9986551Sjake u_int sng_sign:1; 10086551Sjake u_int sng_exp:8; 10186551Sjake u_int sng_frac:23; 10286551Sjake}; 10386551Sjake 10486551Sjakestruct ieee_double { 10586551Sjake u_int dbl_sign:1; 10686551Sjake u_int dbl_exp:11; 10786551Sjake u_int dbl_frach:20; 10886551Sjake u_int dbl_fracl; 10986551Sjake}; 11086551Sjake 11186551Sjakestruct ieee_ext { 11286551Sjake u_int ext_sign:1; 11386551Sjake u_int ext_exp:15; 11486551Sjake u_int ext_frach:16; 11586551Sjake u_int ext_frachm; 11686551Sjake u_int ext_fraclm; 11786551Sjake u_int ext_fracl; 11886551Sjake}; 11986551Sjake 12086551Sjake/* 12186551Sjake * Floats whose exponent is in [1..INFNAN) (of whatever type) are 12286551Sjake * `normal'. Floats whose exponent is INFNAN are either Inf or NaN. 12386551Sjake * Floats whose exponent is zero are either zero (iff all fraction 12486551Sjake * bits are zero) or subnormal values. 12586551Sjake * 12686551Sjake * A NaN is a `signalling NaN' if its QUIETNAN bit is clear in its 12786551Sjake * high fraction; if the bit is set, it is a `quiet NaN'. 12886551Sjake */ 12986551Sjake#define SNG_EXP_INFNAN 255 13086551Sjake#define DBL_EXP_INFNAN 2047 13186551Sjake#define EXT_EXP_INFNAN 32767 13286551Sjake 13386551Sjake#if 0 13486551Sjake#define SNG_QUIETNAN (1 << 22) 13586551Sjake#define DBL_QUIETNAN (1 << 19) 13686551Sjake#define EXT_QUIETNAN (1 << 15) 13786551Sjake#endif 13886551Sjake 13986551Sjake/* 14086551Sjake * Exponent biases. 14186551Sjake */ 14286551Sjake#define SNG_EXP_BIAS 127 14386551Sjake#define DBL_EXP_BIAS 1023 14486551Sjake#define EXT_EXP_BIAS 16383 14586551Sjake 14686551Sjake#endif 147