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