1/*-
2 * Copyright (c) 1992, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
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.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
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.
20 *
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
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
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
35 * $FreeBSD$
36 */
37
38#ifndef _MACHINE_IEEE_H_
39#define	_MACHINE_IEEE_H_
40
41/*
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.
45 */
46
47/*
48 * Define the number of bits in each fraction and exponent.
49 *
50 *		     k	         k+1
51 * Note that  1.0 x 2  == 0.1 x 2      and that denorms are represented
52 *
53 *					  (-exp_bias+1)
54 * as fractions that look like 0.fffff x 2             .  This means that
55 *
56 *			 -126
57 * the number 0.10000 x 2    , for instance, is the same as the normalized
58 *
59 *		-127			   -128
60 * float 1.0 x 2    .  Thus, to represent 2    , we need one leading zero
61 *
62 *				  -129
63 * in the fraction; to represent 2    , we need two, and so on.  This
64 *
65 *						     (-exp_bias-fracbits+1)
66 * implies that the smallest denormalized number is 2
67 *
68 * for whichever format we are talking about: for single precision, for
69 *
70 *						-126		-149
71 * instance, we get .00000000000000000000001 x 2    , or 1.0 x 2    , and
72 *
73 * -149 == -127 - 23 + 1.
74 */
75#define	SNG_EXPBITS	8
76#define	SNG_FRACBITS	23
77
78#define	DBL_EXPBITS	11
79#define	DBL_FRACBITS	52
80
81#ifdef notyet
82#define	E80_EXPBITS	15
83#define	E80_FRACBITS	64
84#endif
85
86#define	EXT_EXPBITS	15
87#define	EXT_FRACBITS	112
88
89struct ieee_single {
90	u_int	sng_sign:1;
91	u_int	sng_exp:8;
92	u_int	sng_frac:23;
93};
94
95struct ieee_double {
96	u_int	dbl_sign:1;
97	u_int	dbl_exp:11;
98	u_int	dbl_frach:20;
99	u_int	dbl_fracl;
100};
101
102struct ieee_ext {
103	u_int	ext_sign:1;
104	u_int	ext_exp:15;
105	u_int	ext_frach:16;
106	u_int	ext_frachm;
107	u_int	ext_fraclm;
108	u_int	ext_fracl;
109};
110
111/*
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.
116 *
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'.
119 */
120#define	SNG_EXP_INFNAN	255
121#define	DBL_EXP_INFNAN	2047
122#define	EXT_EXP_INFNAN	32767
123
124#if 0
125#define	SNG_QUIETNAN	(1 << 22)
126#define	DBL_QUIETNAN	(1 << 19)
127#define	EXT_QUIETNAN	(1 << 15)
128#endif
129
130/*
131 * Exponent biases.
132 */
133#define	SNG_EXP_BIAS	127
134#define	DBL_EXP_BIAS	1023
135#define	EXT_EXP_BIAS	16383
136
137#endif
138