2 * Copyright (c) 1992, 1993
3 * The Regents of the University of California. All rights reserved.
5 * This software was developed by the Computer Systems Engineering group
6 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
7 * contributed to Berkeley.
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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33 * @(#)ieee.h 8.1 (Berkeley) 6/11/93
34 * from: NetBSD: ieee.h,v 1.1.1.1 1998/06/20 04:58:51 eeh Exp
38 #ifndef _MACHINE_IEEE_H_
39 #define _MACHINE_IEEE_H_
42 * ieee.h defines the machine-dependent layout of the machine's IEEE
43 * floating point. It does *not* define (yet?) any of the rounding
44 * mode bits, exceptions, and so forth.
48 * Define the number of bits in each fraction and exponent.
51 * Note that 1.0 x 2 == 0.1 x 2 and that denorms are represented
54 * as fractions that look like 0.fffff x 2 . This means that
57 * the number 0.10000 x 2 , for instance, is the same as the normalized
60 * float 1.0 x 2 . Thus, to represent 2 , we need one leading zero
63 * in the fraction; to represent 2 , we need two, and so on. This
65 * (-exp_bias-fracbits+1)
66 * implies that the smallest denormalized number is 2
68 * for whichever format we are talking about: for single precision, for
71 * instance, we get .00000000000000000000001 x 2 , or 1.0 x 2 , and
73 * -149 == -127 - 23 + 1.
76 #define SNG_FRACBITS 23
78 #define DBL_EXPBITS 11
79 #define DBL_FRACBITS 52
82 #define E80_EXPBITS 15
83 #define E80_FRACBITS 64
86 #define EXT_EXPBITS 15
87 #define EXT_FRACBITS 112
112 * Floats whose exponent is in [1..INFNAN) (of whatever type) are
113 * `normal'. Floats whose exponent is INFNAN are either Inf or NaN.
114 * Floats whose exponent is zero are either zero (iff all fraction
115 * bits are zero) or subnormal values.
117 * A NaN is a `signalling NaN' if its QUIETNAN bit is clear in its
118 * high fraction; if the bit is set, it is a `quiet NaN'.
120 #define SNG_EXP_INFNAN 255
121 #define DBL_EXP_INFNAN 2047
122 #define EXT_EXP_INFNAN 32767
125 #define SNG_QUIETNAN (1 << 22)
126 #define DBL_QUIETNAN (1 << 19)
127 #define EXT_QUIETNAN (1 << 15)
133 #define SNG_EXP_BIAS 127
134 #define DBL_EXP_BIAS 1023
135 #define EXT_EXP_BIAS 16383