1/*	$OpenBSD: fenv.h,v 1.2 2021/05/12 02:28:25 jsg 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_INVALID		0x10
30#define	FE_DIVBYZERO		0x08
31#define	FE_OVERFLOW		0x04
32#define	FE_UNDERFLOW		0x02
33#define	FE_INEXACT		0x01
34
35/*
36 * The following symbol is simply the bitwise-inclusive OR of all floating-point
37 * exception constants defined above.
38 */
39#define	FE_ALL_EXCEPT		(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | \
40				 FE_UNDERFLOW | FE_INEXACT )
41
42/*
43 * Each symbol representing the rounding direction, expands to an integer
44 * constant expression whose value is distinct non-negative value.
45 *
46 * We use such values that allow direct bitwise operations on FPU registers.
47 */
48#define	FE_TONEAREST		0x0
49#define	FE_TOWARDZERO		0x1
50#define	FE_DOWNWARD		0x2
51#define	FE_UPWARD		0x3
52#define	FE_TONEARESTFROMZERO	0x4
53
54/*
55 * The following symbol is simply the bitwise-inclusive OR of all floating-point
56 * rounding direction constants defined above.
57 */
58#define	_ROUND_MASK		(FE_TONEAREST | FE_TOWARDZERO | FE_DOWNWARD | \
59				 FE_UPWARD | FE_TONEARESTFROMZERO)
60#define	_ROUND_SHIFT		5
61
62/*
63 * fenv_t represents the entire floating-point environment.
64 */
65typedef	unsigned int		fenv_t;
66
67/*
68 * The following constant represents the default floating-point environment
69 * (that is, the one installed at program startup) and has type pointer to
70 * const-qualified fenv_t.
71 *
72 * It can be used as an argument to the functions within the <fenv.h> header
73 * that manage the floating-point environment, namely fesetenv() and
74 * feupdateenv().
75 */
76__BEGIN_DECLS
77extern	fenv_t			__fe_dfl_env;
78__END_DECLS
79#define	FE_DFL_ENV		((const fenv_t *)&__fe_dfl_env)
80
81/*
82 * fexcept_t represents the floating-point status flags collectively, including
83 * any status the implementation associates with the flags.
84 *
85 * A floating-point status flag is a system variable whose value is set (but
86 * never cleared) when a floating-point exception is raised, which occurs as a
87 * side effect of exceptional floating-point arithmetic to provide auxiliary
88 * information.
89 *
90 * A floating-point control mode is a system variable whose value may be set by
91 * the user to affect the subsequent behavior of floating-point arithmetic.
92 */
93typedef	unsigned int		fexcept_t;
94
95#endif	/* !_MACHINE_FENV_H_ */
96