1/*	$OpenBSD: fenv.h,v 1.1 2020/06/28 08:19:34 kettenis Exp $	*/
2
3/*
4 * Copyright (c) 2011 Martynas Venckus <martynas@openbsd.org>
5 *
6 * Permission to use, copy, modify, and distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
9 *
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 */
18
19#ifndef	_MACHINE_FENV_H_
20#define	_MACHINE_FENV_H_
21
22/*
23 * Each symbol representing a floating point exception expands to an integer
24 * constant expression with values, such that bitwise-inclusive ORs of _all
25 * combinations_ of the constants result in distinct values.
26 *
27 * We use such values that allow direct bitwise operations on FPU registers.
28 */
29#define	FE_INEXACT		0x02000000
30#define	FE_DIVBYZERO		0x04000000
31#define	FE_UNDERFLOW		0x08000000
32#define	FE_OVERFLOW		0x10000000
33#define	FE_INVALID		0x20000000
34#define	_FE_INVALID_SOFT	0x00000400
35#define	_FE_INVALID_ALL		0x01f80700
36
37/*
38 * The following symbol is simply the bitwise-inclusive OR of all floating-point
39 * exception constants defined above.
40 */
41#define	FE_ALL_EXCEPT		(FE_INEXACT | FE_DIVBYZERO | FE_UNDERFLOW | \
42				 FE_OVERFLOW | FE_INVALID)
43#define	_MASK_SHIFT		22
44
45/*
46 * Each symbol representing the rounding direction, expands to an integer
47 * constant expression whose value is distinct non-negative value.
48 *
49 * We use such values that allow direct bitwise operations on FPU registers.
50 */
51#define	FE_TONEAREST		0x0
52#define	FE_TOWARDZERO		0x1
53#define	FE_UPWARD		0x2
54#define	FE_DOWNWARD		0x3
55
56/*
57 * The following symbol is simply the bitwise-inclusive OR of all floating-point
58 * rounding direction constants defined above.
59 */
60#define	_ROUND_MASK		(FE_TONEAREST | FE_TOWARDZERO | FE_UPWARD | \
61				 FE_DOWNWARD)
62
63/*
64 * fenv_t represents the entire floating-point environment.
65 */
66typedef	unsigned int		fenv_t;
67
68/*
69 * The following constant represents the default floating-point environment
70 * (that is, the one installed at program startup) and has type pointer to
71 * const-qualified fenv_t.
72 *
73 * It can be used as an argument to the functions within the <fenv.h> header
74 * that manage the floating-point environment, namely fesetenv() and
75 * feupdateenv().
76 */
77__BEGIN_DECLS
78extern	fenv_t			__fe_dfl_env;
79__END_DECLS
80#define	FE_DFL_ENV		((const fenv_t *)&__fe_dfl_env)
81
82/*
83 * fexcept_t represents the floating-point status flags collectively, including
84 * any status the implementation associates with the flags.
85 *
86 * A floating-point status flag is a system variable whose value is set (but
87 * never cleared) when a floating-point exception is raised, which occurs as a
88 * side effect of exceptional floating-point arithmetic to provide auxiliary
89 * information.
90 *
91 * A floating-point control mode is a system variable whose value may be set by
92 * the user to affect the subsequent behavior of floating-point arithmetic.
93 */
94typedef	unsigned int		fexcept_t;
95
96#endif	/* !_MACHINE_FENV_H_ */
97