1/* $NetBSD: fenv.h,v 1.2 2014/02/12 23:04:43 dsl Exp $ */
2/*-
3 * Copyright (c) 2004-2005 David Schultz <das (at) FreeBSD.ORG>
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28#ifndef _X86_FENV_H_
29#define _X86_FENV_H_
30
31#ifndef _KERNEL
32#include <sys/stdint.h>
33#endif
34
35/* Default x87 control word. */
36#define __INITIAL_NPXCW__ 0x037f
37/* Modern NetBSD uses the default control word.. */
38#define __NetBSD_NPXCW__ __INITIAL_NPXCW__
39/* NetBSD before 6.99.26 forced IEEE double precision. */
40#define __NetBSD_COMPAT_NPXCW__ 0x127f
41
42/* Default values for the mxcsr. All traps masked. */
43#define __INITIAL_MXCSR__ 0x1f80
44
45#ifndef _KERNEL
46/*
47 * Each symbol representing a floating point exception expands to an integer
48 * constant expression with values, such that bitwise-inclusive ORs of _all
49 * combinations_ of the constants result in distinct values.
50 *
51 * We use such values that allow direct bitwise operations on FPU/SSE registers.
52 */
53#define FE_INVALID 0x01 /* 000000000001 */
54#define FE_DENORMAL 0x02 /* 000000000010 */
55#define FE_DIVBYZERO 0x04 /* 000000000100 */
56#define FE_OVERFLOW 0x08 /* 000000001000 */
57#define FE_UNDERFLOW 0x10 /* 000000010000 */
58#define FE_INEXACT 0x20 /* 000000100000 */
59
60/*
61 * The following symbol is simply the bitwise-inclusive OR of all floating-point
62 * exception constants defined above.
63 */
64#define FE_ALL_EXCEPT (FE_DIVBYZERO | FE_DENORMAL | FE_INEXACT | \
65 FE_INVALID | FE_OVERFLOW | FE_UNDERFLOW)
66
67/*
68 * Each symbol representing the rounding direction, expands to an integer
69 * constant expression whose value is distinct non-negative value.
70 *
71 * We use such values that allow direct bitwise operations on FPU/SSE registers.
72 */
73#define FE_TONEAREST 0x000 /* 000000000000 */
74#define FE_DOWNWARD 0x400 /* 010000000000 */
75#define FE_UPWARD 0x800 /* 100000000000 */
76#define FE_TOWARDZERO 0xC00 /* 110000000000 */
77
78/*
79 * As compared to the x87 control word, the SSE unit's control has the rounding
80 * control bits offset by 3 and the exception mask bits offset by 7
81 */
82#define __X87_ROUND_MASK 0xC00 /* 110000000000 */
83#define __SSE_ROUND_SHIFT 3
84#define __SSE_EMASK_SHIFT 7
85
86/*
87 * fenv_t represents the entire floating-point environment
88 */
89typedef struct {
90 struct {
91 uint16_t control; /* Control word register */
92 uint16_t unused1;
93 uint16_t status; /* Status word register */
94 uint16_t unused2;
95 uint16_t tag; /* Tag word register */
96 uint16_t unused3;
97 uint32_t others[4]; /* EIP, Pointer Selector, etc */
98 } x87;
99
100 uint32_t mxcsr; /* Control and status register */
101} fenv_t;
102
103/*
104 * The following constant represents the default floating-point environment
105 * (that is, the one installed at program startup) and has type pointer to
106 * const-qualified fenv_t.
107 *
108 * It can be used as an argument to the functions within the <fenv.h> header
109 * that manage the floating-point environment.
110 */
111extern fenv_t __fe_dfl_env;
112#define FE_DFL_ENV ((const fenv_t *) &__fe_dfl_env)
113
114/*
115 * fexcept_t represents the floating-point status flags collectively, including
116 * any status the implementation associates with the flags.
117 *
118 * A floating-point status flag is a system variable whose value is set (but
119 * never cleared) when a floating-point exception is raised, which occurs as a
120 * side effect of exceptional floating-point arithmetic to provide auxiliary
121 * information.
122 *
123 * A floating-point control mode is a system variable whose value may be set by
124 * the user to affect the subsequent behavior of floating-point arithmetic.
125 */
126typedef uint32_t fexcept_t;
127#endif
128
129#endif /* ! _X86_FENV_H_ */