1/*	$NetBSD: ieee.h,v 1.13 2024/01/02 19:28:25 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#ifndef _X86_IEEE_H_
43#define _X86_IEEE_H_
44
45/*
46 * ieee.h defines the machine-dependent layout of the machine's IEEE
47 * floating point.  It does *not* define (yet?) any of the rounding
48 * mode bits, exceptions, and so forth.
49 */
50
51#include <sys/ieee754.h>
52
53#define	EXT_EXPBITS	15
54#define EXT_FRACHBITS	32
55#define	EXT_FRACLBITS	32
56#define	EXT_FRACBITS	(EXT_FRACLBITS + EXT_FRACHBITS)
57
58#define	EXT_TO_ARRAY32(u, a) do {			\
59	(a)[0] = (uint32_t)(u).extu_ext.ext_fracl;	\
60	(a)[1] = (uint32_t)(u).extu_ext.ext_frach;	\
61} while(/*CONSTCOND*/0)
62
63/*
64 * struct ieee_ext is the raw storage layout of the 80-bit
65 * extended-precision type as implemented by the FPU.  Per the
66 * respective ABI specifications, it is followed by a tail padding of
67 *
68 *   amd64: 48 bits,
69 *   i386:  16 bits.
70 */
71struct ieee_ext {
72	uint32_t	ext_fracl:EXT_FRACLBITS;
73	uint32_t	ext_frach:EXT_FRACHBITS;
74#if 0
75	uint32_t	ext_int:1;
76#endif
77	uint32_t	ext_exp:EXT_EXPBITS;
78	uint32_t	ext_sign:1;
79};
80
81/*
82 * Floats whose exponent is in [1..INFNAN) (of whatever type) are
83 * `normal'.  Floats whose exponent is INFNAN are either Inf or NaN.
84 * Floats whose exponent is zero are either zero (iff all fraction
85 * bits are zero) or subnormal values.
86 *
87 * A NaN is a `signalling NaN' if its QUIETNAN bit is clear in its
88 * high fraction; if the bit is set, it is a `quiet NaN'.
89 */
90#define	EXT_EXP_INFNAN	0x7fff
91#define	EXT_EXP_INF	0x7fff
92#define	EXT_EXP_NAN	0x7fff
93
94#if 0
95#define	SNG_QUIETNAN	(1 << 22)
96#define	DBL_QUIETNAN	(1 << 19)
97#define	EXT_QUIETNAN	(1 << 30)
98#endif
99
100/*
101 * Exponent biases.
102 */
103#define	EXT_EXP_BIAS	16383
104
105/*
106 * Convenience data structures.
107 */
108union ieee_ext_u {
109	long double		extu_ld;
110	struct ieee_ext		extu_ext;
111};
112
113#define extu_exp	extu_ext.ext_exp
114#define extu_sign	extu_ext.ext_sign
115#define extu_fracl	extu_ext.ext_fracl
116#define extu_frach	extu_ext.ext_frach
117
118#define LDBL_NBIT	0x80000000
119#define mask_nbit_l(u)	((u).extu_frach &= ~LDBL_NBIT)
120
121#endif /* _X86_IEEE_H_ */
122