1 /* $NetBSD: ieee754.h,v 1.3 2003/10/27 01:11:47 kleink Exp $ */
2 /* $DragonFly: src/sys/sys/ieee754.h,v 1.2 2004/12/30 15:53:35 asmodai Exp $ */
5 * Copyright (c) 1992, 1993
6 * The Regents of the University of California. All rights reserved.
8 * This software was developed by the Computer Systems Engineering group
9 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
10 * contributed to Berkeley.
12 * All advertising materials mentioning features or use of this software
13 * must display the following acknowledgement:
14 * This product includes software developed by the University of
15 * California, Lawrence Berkeley Laboratory.
17 * Redistribution and use in source and binary forms, with or without
18 * modification, are permitted provided that the following conditions
20 * 1. Redistributions of source code must retain the above copyright
21 * notice, this list of conditions and the following disclaimer.
22 * 2. Redistributions in binary form must reproduce the above copyright
23 * notice, this list of conditions and the following disclaimer in the
24 * documentation and/or other materials provided with the distribution.
25 * 3. Neither the name of the University nor the names of its contributors
26 * may be used to endorse or promote products derived from this software
27 * without specific prior written permission.
29 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
30 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
31 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
32 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
33 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
34 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
35 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
36 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
37 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
38 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
41 * @(#)ieee.h 8.1 (Berkeley) 6/11/93
45 * NOTICE: This is not a standalone file. To use it, #include it in
46 * your port's ieee.h header.
49 #include <sys/types.h>
50 #include <machine/endian.h>
53 * <sys/ieee754.h> defines the layout of IEEE 754 floating point types.
54 * Only single-precision and double-precision types are defined here;
55 * extended types, if available, are defined in the machine-dependent
60 * Define the number of bits in each fraction and exponent.
63 * Note that 1.0 x 2 == 0.1 x 2 and that denorms are represented
66 * as fractions that look like 0.fffff x 2 . This means that
69 * the number 0.10000 x 2 , for instance, is the same as the normalized
72 * float 1.0 x 2 . Thus, to represent 2 , we need one leading zero
75 * in the fraction; to represent 2 , we need two, and so on. This
77 * (-exp_bias-fracbits+1)
78 * implies that the smallest denormalized number is 2
80 * for whichever format we are talking about: for single precision, for
83 * instance, we get .00000000000000000000001 x 2 , or 1.0 x 2 , and
85 * -149 == -127 - 23 + 1.
88 #define SNG_FRACBITS 23
90 #define DBL_EXPBITS 11
91 #define DBL_FRACBITS 52
94 #if _BYTE_ORDER == _BIG_ENDIAN
106 #if _BYTE_ORDER == _BIG_ENDIAN
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.
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'.
128 #define SNG_EXP_INFNAN 255
129 #define DBL_EXP_INFNAN 2047
132 #define SNG_QUIETNAN (1 << 22)
133 #define DBL_QUIETNAN (1 << 19)
139 #define SNG_EXP_BIAS 127
140 #define DBL_EXP_BIAS 1023
143 * Convenience data structures.
145 union ieee_single_u {
147 struct ieee_single sngu_sng;
150 union ieee_double_u {
152 struct ieee_double dblu_dbl;