1/* $OpenBSD: fenv.h,v 1.3 2019/03/12 22:14:50 patrick 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 0x01
30#define FE_DIVBYZERO 0x02
31#define FE_OVERFLOW 0x04
32#define FE_UNDERFLOW 0x08
33#define FE_INEXACT 0x10
34#define FE_DENORMAL 0x80
35
36/*
37 * The following symbol is simply the bitwise-inclusive OR of all floating-point
38 * exception constants defined above.
39 */
40#define FE_ALL_EXCEPT (FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | \
41 FE_UNDERFLOW | FE_INEXACT | FE_DENORMAL)
42
43/*
44 * Each symbol representing the rounding direction, expands to an integer
45 * constant expression whose value is distinct non-negative value.
46 *
47 * We use such values that allow direct bitwise operations on FPU registers.
48 */
49#define FE_TONEAREST 0x0
50#define FE_UPWARD 0x1
51#define FE_DOWNWARD 0x2
52#define FE_TOWARDZERO 0x3
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_UPWARD | FE_DOWNWARD | \
59 FE_TOWARDZERO)
60#define _ROUND_SHIFT 22
61
62/*
63 * fenv_t represents the entire floating-point environment.
64 */
65typedef unsigned long long 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 long long fexcept_t;
94
95#endif /* !_MACHINE_FENV_H_ */