ieee.h revision 1.8 
1/*	$NetBSD: ieee.h,v 1.8 2003/10/27 01:11:47 kleink Exp $ */
2
3/*
4 * Copyright (c) 1992, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
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.
10 *
11 * All advertising materials mentioning features or use of this software
12 * must display the following acknowledgement:
13 *	This product includes software developed by the University of
14 *	California, Lawrence Berkeley Laboratory.
15 *
16 * Redistribution and use in source and binary forms, with or without
17 * modification, are permitted provided that the following conditions
18 * are met:
19 * 1. Redistributions of source code must retain the above copyright
20 *    notice, this list of conditions and the following disclaimer.
21 * 2. Redistributions in binary form must reproduce the above copyright
22 *    notice, this list of conditions and the following disclaimer in the
23 *    documentation and/or other materials provided with the distribution.
24 * 3. Neither the name of the University nor the names of its contributors
25 *    may be used to endorse or promote products derived from this software
26 *    without specific prior written permission.
27 *
28 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
31 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38 * SUCH DAMAGE.
39 *
40 *	@(#)ieee.h	8.1 (Berkeley) 6/11/93
41 */
42
43/*
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.
47 */
48
49#include <sys/ieee754.h>
50
51#define	EXT_EXPBITS	15
52#define	EXT_FRACBITS	64
53
54/*
55 * struct ieee_ext is the raw storage layout of the 80-bit
56 * extended-precision type as implemented by the FPU.  Per the
57 * respective ABI specifications, it is followed by a tail padding of
58 *
59 *   amd64: 48 bits,
60 *   i386:  16 bits.
61 */
62struct ieee_ext {
63	u_int	ext_fracl;
64	u_int	ext_frach:31;
65	u_int	ext_int:1;
66	u_int	ext_exp:15;
67	u_int	ext_sign:1;
68};
69
70/*
71 * Floats whose exponent is in [1..INFNAN) (of whatever type) are
72 * `normal'.  Floats whose exponent is INFNAN are either Inf or NaN.
73 * Floats whose exponent is zero are either zero (iff all fraction
74 * bits are zero) or subnormal values.
75 *
76 * A NaN is a `signalling NaN' if its QUIETNAN bit is clear in its
77 * high fraction; if the bit is set, it is a `quiet NaN'.
78 */
79#define	EXT_EXP_INFNAN	32767
80
81#if 0
82#define	EXT_QUIETNAN	(1 << 30)
83#endif
84
85/*
86 * Exponent biases.
87 */
88#define	EXT_EXP_BIAS	16383
89
90/*
91 * Convenience data structures.
92 */
93union ieee_ext_u {
94	long double		extu_ld;
95	struct ieee_ext		extu_ext;
96};
97