1 /*	$NetBSD: ieee.h,v 1.9.32.1 2007/05/07 19:49:10 pavel 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_FRACHBITS	32
53 #define	EXT_FRACLBITS	32
54 #define	EXT_FRACBITS	(EXT_FRACLBITS + EXT_FRACHBITS)
55 
56 #define	EXT_TO_ARRAY32(u, a) do {			\
57 	(a)[0] = (uint32_t)(u).extu_ext.ext_fracl;	\
58 	(a)[1] = (uint32_t)(u).extu_ext.ext_frach;	\
59 } while(/*CONSTCOND*/0)
60 
61 /*
62  * struct ieee_ext is the raw storage layout of the 80-bit
63  * extended-precision type as implemented by the FPU.  Per the
64  * respective ABI specifications, it is followed by a tail padding of
65  *
66  *   amd64: 48 bits,
67  *   i386:  16 bits.
68  */
69 struct ieee_ext {
70 	u_int	ext_fracl:EXT_FRACLBITS;
71 	u_int	ext_frach:EXT_FRACHBITS;
72 #if 0
73 	u_int	ext_int:1;
74 #endif
75 	u_int	ext_exp:EXT_EXPBITS;
76 	u_int	ext_sign:1;
77 };
78 
79 /*
80  * Floats whose exponent is in [1..INFNAN) (of whatever type) are
81  * `normal'.  Floats whose exponent is INFNAN are either Inf or NaN.
82  * Floats whose exponent is zero are either zero (iff all fraction
83  * bits are zero) or subnormal values.
84  *
85  * A NaN is a `signalling NaN' if its QUIETNAN bit is clear in its
86  * high fraction; if the bit is set, it is a `quiet NaN'.
87  */
88 #define	EXT_EXP_INFNAN	32767
89 
90 #if 0
91 #define	SNG_QUIETNAN	(1 << 22)
92 #define	DBL_QUIETNAN	(1 << 19)
93 #define	EXT_QUIETNAN	(1 << 30)
94 #endif
95 
96 /*
97  * Exponent biases.
98  */
99 #define	EXT_EXP_BIAS	16383
100 
101 /*
102  * Convenience data structures.
103  */
104 union ieee_ext_u {
105 	long double		extu_ld;
106 	struct ieee_ext		extu_ext;
107 };
108