2 * SPDX-License-Identifier: BSD-3-Clause
4 * Copyright (c) 1992, 1993
5 * The Regents of the University of California. All rights reserved.
7 * This software was developed by the Computer Systems Engineering group
8 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
9 * contributed to Berkeley.
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12 * modification, are permitted provided that the following conditions
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35 * @(#)ieee.h 8.1 (Berkeley) 6/11/93
36 * from: NetBSD: ieee.h,v 1.1.1.1 1998/06/20 04:58:51 eeh Exp
40 #ifndef _MACHINE_IEEE_H_
41 #define _MACHINE_IEEE_H_
44 * ieee.h defines the machine-dependent layout of the machine's IEEE
45 * floating point. It does *not* define (yet?) any of the rounding
46 * mode bits, exceptions, and so forth.
50 * Define the number of bits in each fraction and exponent.
53 * Note that 1.0 x 2 == 0.1 x 2 and that denorms are represented
56 * as fractions that look like 0.fffff x 2 . This means that
59 * the number 0.10000 x 2 , for instance, is the same as the normalized
62 * float 1.0 x 2 . Thus, to represent 2 , we need one leading zero
65 * in the fraction; to represent 2 , we need two, and so on. This
67 * (-exp_bias-fracbits+1)
68 * implies that the smallest denormalized number is 2
70 * for whichever format we are talking about: for single precision, for
73 * instance, we get .00000000000000000000001 x 2 , or 1.0 x 2 , and
75 * -149 == -127 - 23 + 1.
78 #define SNG_FRACBITS 23
80 #define DBL_EXPBITS 11
81 #define DBL_FRACBITS 52
84 #define E80_EXPBITS 15
85 #define E80_FRACBITS 64
88 #define EXT_EXPBITS 15
89 #define EXT_FRACBITS 112
114 * Floats whose exponent is in [1..INFNAN) (of whatever type) are
115 * `normal'. Floats whose exponent is INFNAN are either Inf or NaN.
116 * Floats whose exponent is zero are either zero (iff all fraction
117 * bits are zero) or subnormal values.
119 * A NaN is a `signalling NaN' if its QUIETNAN bit is clear in its
120 * high fraction; if the bit is set, it is a `quiet NaN'.
122 #define SNG_EXP_INFNAN 255
123 #define DBL_EXP_INFNAN 2047
124 #define EXT_EXP_INFNAN 32767
127 #define SNG_QUIETNAN (1 << 22)
128 #define DBL_QUIETNAN (1 << 19)
129 #define EXT_QUIETNAN (1 << 15)
135 #define SNG_EXP_BIAS 127
136 #define DBL_EXP_BIAS 1023
137 #define EXT_EXP_BIAS 16383