xref: /netbsd/sys/arch/m68k/include/ieee.h (revision 6550d01e)
1 /*	$NetBSD: ieee.h,v 1.16 2010/09/20 16:13:35 christos 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 #if !defined(__mc68010__) || defined(_KERNEL)
52 #define	EXT_EXPBITS	15
53 #define	EXT_FRACHBITS	32
54 #define	EXT_FRACLBITS	32
55 #define	EXT_FRACBITS	(EXT_FRACLBITS + EXT_FRACHBITS)
56 
57 #define	EXT_TO_ARRAY32(u, a) do {			\
58 	(a)[0] = (uint32_t)(u).extu_ext.ext_fracl;	\
59 	(a)[1] = (uint32_t)(u).extu_ext.ext_frach;	\
60 } while(/*CONSTCOND*/0)
61 
62 struct ieee_ext {
63 	u_int	ext_sign:1;
64 	u_int	ext_exp:EXT_EXPBITS;
65 	u_int	ext_zero:16;
66 #if 0
67 	u_int	ext_int:1;
68 #endif
69 	u_int	ext_frach;
70 	u_int	ext_fracl;
71 };
72 
73 /*
74  * Extended floats whose exponent is in [0..INFNAN) and have their
75  * explicit integer bit (the most significant bit of the fraction)
76  * set are `normal'.  Floats whose exponent is INFNAN are either Inf or NaN.
77  * Floats whose exponent is zero are either zero (iff all fraction
78  * bits are zero) or subnormal values.
79  *
80  * A NaN is a `signalling NaN' if its QUIETNAN bit is clear in its
81  * high fraction; if the bit is set, it is a `quiet NaN'.
82  */
83 #define	EXT_EXP_INFNAN	0x7fff
84 #define	EXT_EXP_INF	0x7fff
85 #define	EXT_EXP_NAN	0x7fff
86 
87 #if 0
88 #define	SNG_QUIETNAN	(1 << 22)
89 #define	DBL_QUIETNAN	(1 << 19)
90 #define	EXT_QUIETNAN	(1 << 30)
91 #endif
92 
93 /*
94  * Exponent biases.
95  */
96 #define	EXT_EXP_BIAS	16383
97 
98 /*
99  * Convenience data structures.
100  */
101 union ieee_ext_u {
102 	long double		extu_ld;
103 	struct ieee_ext		extu_ext;
104 };
105 
106 #define extu_exp	extu_ext.ext_exp
107 #define extu_sign	extu_ext.ext_sign
108 #define extu_fracl	extu_ext.ext_fracl
109 #define extu_frach	extu_ext.ext_frach
110 
111 #define LDBL_NBIT	0x80000000
112 #define mask_nbit_l(u)	((u).extu_frach &= ~LDBL_NBIT)
113 #endif /* !__mc68010__ || _KERNEL */
114