1 /* $NetBSD: ieee.h,v 1.1 2002/06/05 01:04:22 fredette Exp $ */ 2 3 /* $OpenBSD: ieee.h,v 1.1 1999/04/20 19:44:04 mickey Exp $ */ 4 5 /* 6 * Copyright (c) 1992, 1993 7 * The Regents of the University of California. All rights reserved. 8 * 9 * This software was developed by the Computer Systems Engineering group 10 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and 11 * contributed to Berkeley. 12 * 13 * All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Lawrence Berkeley Laboratory. 17 * 18 * Redistribution and use in source and binary forms, with or without 19 * modification, are permitted provided that the following conditions 20 * are met: 21 * 1. Redistributions of source code must retain the above copyright 22 * notice, this list of conditions and the following disclaimer. 23 * 2. Redistributions in binary form must reproduce the above copyright 24 * notice, this list of conditions and the following disclaimer in the 25 * documentation and/or other materials provided with the distribution. 26 * 3. All advertising materials mentioning features or use of this software 27 * must display the following acknowledgement: 28 * This product includes software developed by the University of 29 * California, Berkeley and its contributors. 30 * 4. Neither the name of the University nor the names of its contributors 31 * may be used to endorse or promote products derived from this software 32 * without specific prior written permission. 33 * 34 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 35 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 36 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 37 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 38 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 39 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 40 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 41 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 42 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 43 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 44 * SUCH DAMAGE. 45 * 46 * @(#)ieee.h 8.1 (Berkeley) 6/11/93 47 */ 48 49 /* 50 * ieee.h defines the machine-dependent layout of the machine's IEEE 51 * floating point. It does *not* define (yet?) any of the rounding 52 * mode bits, exceptions, and so forth. 53 */ 54 55 /* 56 * Define the number of bits in each fraction and exponent. 57 * 58 * k k+1 59 * Note that 1.0 x 2 == 0.1 x 2 and that denorms are represented 60 * 61 * (-exp_bias+1) 62 * as fractions that look like 0.fffff x 2 . This means that 63 * 64 * -126 65 * the number 0.10000 x 2 , for instance, is the same as the normalized 66 * 67 * -127 -128 68 * float 1.0 x 2 . Thus, to represent 2 , we need one leading zero 69 * 70 * -129 71 * in the fraction; to represent 2 , we need two, and so on. This 72 * 73 * (-exp_bias-fracbits+1) 74 * implies that the smallest denormalized number is 2 75 * 76 * for whichever format we are talking about: for single precision, for 77 * 78 * -126 -149 79 * instance, we get .00000000000000000000001 x 2 , or 1.0 x 2 , and 80 * 81 * -149 == -127 - 23 + 1. 82 */ 83 #define SNG_EXPBITS 8 84 #define SNG_FRACBITS 23 85 86 #define DBL_EXPBITS 11 87 #define DBL_FRACBITS 52 88 89 #ifdef notyet 90 #define E80_EXPBITS 15 91 #define E80_FRACBITS 64 92 #endif 93 94 #define EXT_EXPBITS 15 95 #define EXT_FRACBITS 112 96 97 struct ieee_single { 98 u_int sng_sign:1; 99 u_int sng_exp:8; 100 u_int sng_frac:23; 101 }; 102 103 struct ieee_double { 104 u_int dbl_sign:1; 105 u_int dbl_exp:11; 106 u_int dbl_frach:20; 107 u_int dbl_fracl; 108 }; 109 110 struct ieee_ext { 111 u_int ext_sign:1; 112 u_int ext_exp:15; 113 u_int ext_frach:16; 114 u_int ext_frachm; 115 u_int ext_fraclm; 116 u_int ext_fracl; 117 }; 118 119 /* 120 * Floats whose exponent is in [1..INFNAN) (of whatever type) are 121 * `normal'. Floats whose exponent is INFNAN are either Inf or NaN. 122 * Floats whose exponent is zero are either zero (iff all fraction 123 * bits are zero) or subnormal values. 124 * 125 * A NaN is a `signalling NaN' if its QUIETNAN bit is clear in its 126 * high fraction; if the bit is set, it is a `quiet NaN'. 127 */ 128 #define SNG_EXP_INFNAN 255 129 #define DBL_EXP_INFNAN 2047 130 #define EXT_EXP_INFNAN 32767 131 132 #if 0 133 #define SNG_QUIETNAN (1 << 22) 134 #define DBL_QUIETNAN (1 << 19) 135 #define EXT_QUIETNAN (1 << 15) 136 #endif 137 138 /* 139 * Exponent biases. 140 */ 141 #define SNG_EXP_BIAS 127 142 #define DBL_EXP_BIAS 1023 143 #define EXT_EXP_BIAS 16383 144