1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2004-2011 David Schultz <das@FreeBSD.ORG>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 *
28 * $FreeBSD$
29 */
30
31#ifndef	_FENV_H_
32#error "This file is meant to be included only by <fenv.h>."
33#endif
34
35/*
36 * This file implements the functionality of <fenv.h> on platforms that
37 * lack an FPU and use softfloat in libc for floating point.  To use it,
38 * you must write an <fenv.h> that provides the following:
39 *
40 *   - a typedef for fenv_t, which may be an integer or struct type
41 *   - a typedef for fexcept_t (XXX This file assumes fexcept_t is a
42 *     simple integer type containing the exception mask.)
43 *   - definitions of FE_* constants for the five exceptions and four
44 *     rounding modes in IEEE 754, as described in fenv(3)
45 *   - a definition, and the corresponding external symbol, for FE_DFL_ENV
46 *   - a macro __set_env(env, flags, mask, rnd), which sets the given fenv_t
47 *     from the exception flags, mask, and rounding mode
48 *   - macros __env_flags(env), __env_mask(env), and __env_round(env), which
49 *     extract fields from an fenv_t
50 *   - a definition of __fenv_static
51 *
52 * If the architecture supports an optional FPU, it's recommended that you
53 * define fenv_t and fexcept_t to match the hardware ABI.  Otherwise, it
54 * doesn't matter how you define them.
55 */
56
57extern int __softfloat_float_exception_flags;
58extern int __softfloat_float_exception_mask;
59extern int __softfloat_float_rounding_mode;
60void __softfloat_float_raise(int);
61
62__fenv_static inline int
63feclearexcept(int __excepts)
64{
65
66	__softfloat_float_exception_flags &= ~__excepts;
67	return (0);
68}
69
70__fenv_static inline int
71fegetexceptflag(fexcept_t *__flagp, int __excepts)
72{
73
74	*__flagp = __softfloat_float_exception_flags & __excepts;
75	return (0);
76}
77
78__fenv_static inline int
79fesetexceptflag(const fexcept_t *__flagp, int __excepts)
80{
81
82	__softfloat_float_exception_flags &= ~__excepts;
83	__softfloat_float_exception_flags |= *__flagp & __excepts;
84	return (0);
85}
86
87__fenv_static inline int
88feraiseexcept(int __excepts)
89{
90
91	__softfloat_float_raise(__excepts);
92	return (0);
93}
94
95__fenv_static inline int
96fetestexcept(int __excepts)
97{
98
99	return (__softfloat_float_exception_flags & __excepts);
100}
101
102__fenv_static inline int
103fegetround(void)
104{
105
106	return (__softfloat_float_rounding_mode);
107}
108
109__fenv_static inline int
110fesetround(int __round)
111{
112
113	__softfloat_float_rounding_mode = __round;
114	return (0);
115}
116
117__fenv_static inline int
118fegetenv(fenv_t *__envp)
119{
120
121	__set_env(*__envp, __softfloat_float_exception_flags,
122	    __softfloat_float_exception_mask, __softfloat_float_rounding_mode);
123	return (0);
124}
125
126__fenv_static inline int
127feholdexcept(fenv_t *__envp)
128{
129	fenv_t __env;
130
131	fegetenv(__envp);
132	__softfloat_float_exception_flags = 0;
133	__softfloat_float_exception_mask = 0;
134	return (0);
135}
136
137__fenv_static inline int
138fesetenv(const fenv_t *__envp)
139{
140
141	__softfloat_float_exception_flags = __env_flags(*__envp);
142	__softfloat_float_exception_mask = __env_mask(*__envp);
143	__softfloat_float_rounding_mode = __env_round(*__envp);
144	return (0);
145}
146
147__fenv_static inline int
148feupdateenv(const fenv_t *__envp)
149{
150	int __oflags = __softfloat_float_exception_flags;
151
152	fesetenv(__envp);
153	feraiseexcept(__oflags);
154	return (0);
155}
156
157#if __BSD_VISIBLE
158
159/* We currently provide no external definitions of the functions below. */
160
161__fenv_static inline int
162feenableexcept(int __mask)
163{
164	int __omask = __softfloat_float_exception_mask;
165
166	__softfloat_float_exception_mask |= __mask;
167	return (__omask);
168}
169
170__fenv_static inline int
171fedisableexcept(int __mask)
172{
173	int __omask = __softfloat_float_exception_mask;
174
175	__softfloat_float_exception_mask &= ~__mask;
176	return (__omask);
177}
178
179__fenv_static inline int
180fegetexcept(void)
181{
182
183	return (__softfloat_float_exception_mask);
184}
185
186#endif /* __BSD_VISIBLE */
187