1 /* $OpenBSD: ieee.h,v 1.2 2003/06/02 23:27:47 millert Exp $ */
2 /* $NetBSD: ieee.h,v 1.1 1996/09/30 16:34:25 ws 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.
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13 * must display the following acknowledgement:
14 * This product includes software developed by the University of
15 * California, Lawrence Berkeley Laboratory.
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18 * modification, are permitted provided that the following conditions
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22 * 2. Redistributions in binary form must reproduce the above copyright
23 * notice, this list of conditions and the following disclaimer in the
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26 * may be used to endorse or promote products derived from this software
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41 * @(#)ieee.h 8.1 (Berkeley) 6/11/93
45 * ieee.h defines the machine-dependent layout of the machine's IEEE
46 * floating point. It does *not* define (yet?) any of the rounding
47 * mode bits, exceptions, and so forth.
51 * Define the number of bits in each fraction and exponent.
54 * Note that 1.0 x 2 == 0.1 x 2 and that denorms are represented
57 * as fractions that look like 0.fffff x 2 . This means that
60 * the number 0.10000 x 2 , for instance, is the same as the normalized
63 * float 1.0 x 2 . Thus, to represent 2 , we need one leading zero
66 * in the fraction; to represent 2 , we need two, and so on. This
68 * (-exp_bias-fracbits+1)
69 * implies that the smallest denormalized number is 2
71 * for whichever format we are talking about: for single precision, for
74 * instance, we get .00000000000000000000001 x 2 , or 1.0 x 2 , and
76 * -149 == -127 - 23 + 1.
79 #define SNG_FRACBITS 23
81 #define DBL_EXPBITS 11
82 #define DBL_FRACBITS 52
84 #define EXT_EXPBITS 15
85 #define EXT_FRACBITS 112
110 * Floats whose exponent is in [1..INFNAN) (of whatever type) are
111 * `normal'. Floats whose exponent is INFNAN are either Inf or NaN.
112 * Floats whose exponent is zero are either zero (iff all fraction
113 * bits are zero) or subnormal values.
115 * A NaN is a `signalling NaN' if its QUIETNAN bit is clear in its
116 * high fraction; if the bit is set, it is a `quiet NaN'.
118 #define SNG_EXP_INFNAN 255
119 #define DBL_EXP_INFNAN 2047
120 #define EXT_EXP_INFNAN 32767
123 #define SNG_QUIETNAN (1 << 22)
124 #define DBL_QUIETNAN (1 << 19)
125 #define EXT_QUIETNAN (1 << 15)
131 #define SNG_EXP_BIAS 127
132 #define DBL_EXP_BIAS 1023
133 #define EXT_EXP_BIAS 16383