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_ */