1/*	$OpenBSD: fenv.h,v 1.3 2011/05/25 21:46:49 martynas Exp $	*/
2/*	$NetBSD: fenv.h,v 1.1.6.2 2010/10/24 22:48:02 jym Exp $	*/
3
4/*-
5 * Copyright (c) 2004-2005 David Schultz <das (at) FreeBSD.ORG>
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30#ifndef	_I386_FENV_H_
31#define	_I386_FENV_H_
32
33/*
34 * Each symbol representing a floating point exception expands to an integer
35 * constant expression with values, such that bitwise-inclusive ORs of _all
36 * combinations_ of the constants result in distinct values.
37 *
38 * We use such values that allow direct bitwise operations on FPU/SSE registers.
39 */
40#define	FE_INVALID		0x01
41#define	FE_DENORMAL		0x02
42#define	FE_DIVBYZERO		0x04
43#define	FE_OVERFLOW		0x08
44#define	FE_UNDERFLOW		0x10
45#define	FE_INEXACT		0x20
46
47/*
48 * The following symbol is simply the bitwise-inclusive OR of all floating-point
49 * exception constants defined above.
50 */
51#define	FE_ALL_EXCEPT		(FE_INVALID | FE_DENORMAL | FE_DIVBYZERO | \
52				 FE_OVERFLOW | FE_UNDERFLOW | FE_INEXACT)
53#define	_SSE_MASK_SHIFT		7
54
55/*
56 * Each symbol representing the rounding direction, expands to an integer
57 * constant expression whose value is distinct non-negative value.
58 *
59 * We use such values that allow direct bitwise operations on FPU/SSE registers.
60 */
61#define	FE_TONEAREST		0x000
62#define	FE_DOWNWARD		0x400
63#define	FE_UPWARD		0x800
64#define	FE_TOWARDZERO		0xc00
65
66/*
67 * The following symbol is simply the bitwise-inclusive OR of all floating-point
68 * rounding direction constants defined above.
69 */
70#define	_X87_ROUND_MASK		(FE_TONEAREST | FE_DOWNWARD | FE_UPWARD | \
71				 FE_TOWARDZERO)
72#define	_SSE_ROUND_SHIFT	3
73
74/*
75 * fenv_t represents the entire floating-point environment.
76 */
77typedef	struct {
78	struct {
79		unsigned int __control;		/* Control word register */
80		unsigned int __status;		/* Status word register */
81		unsigned int __tag;		/* Tag word register */
82		unsigned int __others[4];	/* EIP, Pointer Selector, etc */
83	} __x87;
84	unsigned int __mxcsr;			/* Control, status register */
85} fenv_t;
86
87/*
88 * The following constant represents the default floating-point environment
89 * (that is, the one installed at program startup) and has type pointer to
90 * const-qualified fenv_t.
91 *
92 * It can be used as an argument to the functions within the <fenv.h> header
93 * that manage the floating-point environment, namely fesetenv() and
94 * feupdateenv().
95 */
96__BEGIN_DECLS
97extern	fenv_t			__fe_dfl_env;
98__END_DECLS
99#define	FE_DFL_ENV		((const fenv_t *)&__fe_dfl_env)
100
101/*
102 * fexcept_t represents the floating-point status flags collectively, including
103 * any status the implementation associates with the flags.
104 *
105 * A floating-point status flag is a system variable whose value is set (but
106 * never cleared) when a floating-point exception is raised, which occurs as a
107 * side effect of exceptional floating-point arithmetic to provide auxiliary
108 * information.
109 *
110 * A floating-point control mode is a system variable whose value may be set by
111 * the user to affect the subsequent behavior of floating-point arithmetic.
112 */
113typedef	unsigned int		fexcept_t;
114
115#endif	/* !_I386_FENV_H_ */
116