fenv.h revision 140219 
1/*-
2 * Copyright (c) 2004 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: head/lib/msun/i387/fenv.h 140219 2005-01-14 07:09:23Z das $
27 */
28
29#ifndef	_FENV_H_
30#define	_FENV_H_
31
32#include <sys/cdefs.h>
33#include <sys/_types.h>
34
35typedef struct {
36	__uint32_t	__control;
37	__uint32_t	__status;
38	__uint32_t	__tag;
39	char		__other[16];
40} fenv_t;
41
42typedef	__uint16_t	fexcept_t;
43
44/* Exception flags */
45#define	FE_INVALID	0x01
46#define	FE_DENORMAL	0x02
47#define	FE_DIVBYZERO	0x04
48#define	FE_OVERFLOW	0x08
49#define	FE_UNDERFLOW	0x10
50#define	FE_INEXACT	0x20
51#define	FE_ALL_EXCEPT	(FE_DIVBYZERO | FE_DENORMAL | FE_INEXACT | \
52			 FE_INVALID | FE_OVERFLOW | FE_UNDERFLOW)
53
54/* Rounding modes */
55#define	FE_TONEAREST	0x0000
56#define	FE_DOWNWARD	0x0400
57#define	FE_UPWARD	0x0800
58#define	FE_TOWARDZERO	0x0c00
59#define	_ROUND_MASK	(FE_TONEAREST | FE_DOWNWARD | \
60			 FE_UPWARD | FE_TOWARDZERO)
61
62__BEGIN_DECLS
63
64/* Default floating-point environment */
65extern const fenv_t	__fe_dfl_env;
66#define	FE_DFL_ENV	(&__fe_dfl_env)
67
68#define	__fldcw(__cw)		__asm __volatile("fldcw %0" : : "m" (__cw))
69#define	__fldenv(__env)		__asm __volatile("fldenv %0" : : "m" (__env))
70#define	__fnclex()		__asm __volatile("fnclex")
71#define	__fnstenv(__env)	__asm __volatile("fnstenv %0" : "=m" (*(__env)))
72#define	__fnstcw(__cw)		__asm __volatile("fnstcw %0" : "=m" (*(__cw)))
73#define	__fnstsw(__sw)		__asm __volatile("fnstsw %0" : "=am" (*(__sw)))
74#define	__fwait()		__asm __volatile("fwait")
75
76static __inline int
77feclearexcept(int __excepts)
78{
79	fenv_t __env;
80
81	if (__excepts == FE_ALL_EXCEPT) {
82		__fnclex();
83	} else {
84		__fnstenv(&__env);
85		__env.__status &= ~__excepts;
86		__fldenv(__env);
87	}
88	return (0);
89}
90
91static __inline int
92fegetexceptflag(fexcept_t *__flagp, int __excepts)
93{
94	int __status;
95
96	__fnstsw(&__status);
97	*__flagp = __status & __excepts;
98	return (0);
99}
100
101static __inline int
102fesetexceptflag(const fexcept_t *__flagp, int __excepts)
103{
104	fenv_t __env;
105
106	__fnstenv(&__env);
107	__env.__status &= ~__excepts;
108	__env.__status |= *__flagp & __excepts;
109	__fldenv(__env);
110	return (0);
111}
112
113static __inline int
114feraiseexcept(int __excepts)
115{
116	fexcept_t __ex = __excepts;
117
118	fesetexceptflag(&__ex, __excepts);
119	__fwait();
120	return (0);
121}
122
123static __inline int
124fetestexcept(int __excepts)
125{
126	int __status;
127
128	__fnstsw(&__status);
129	return (__status & __excepts);
130}
131
132static __inline int
133fegetround(void)
134{
135	int __control;
136
137	__fnstcw(&__control);
138	return (__control & _ROUND_MASK);
139}
140
141static __inline int
142fesetround(int __round)
143{
144	int __control;
145
146	if (__round & ~_ROUND_MASK)
147		return (-1);
148	__fnstcw(&__control);
149	__control &= ~_ROUND_MASK;
150	__control |= __round;
151	__fldcw(__control);
152	return (0);
153}
154
155static __inline int
156fegetenv(fenv_t *__envp)
157{
158	int __control;
159
160	/*
161	 * fnstenv masks all exceptions, so we need to save and
162	 * restore the control word to avoid this side effect.
163	 */
164	__fnstcw(&__control);
165	__fnstenv(__envp);
166	__fldcw(__control);
167	return (0);
168}
169
170static __inline int
171feholdexcept(fenv_t *__envp)
172{
173
174	__fnstenv(__envp);
175	__fnclex();
176	return (0);
177}
178
179static __inline int
180fesetenv(const fenv_t *__envp)
181{
182
183	__fldenv(*__envp);
184	return (0);
185}
186
187static __inline int
188feupdateenv(const fenv_t *__envp)
189{
190	int __status;
191
192	__fnstsw(&__status);
193	__fldenv(*__envp);
194	feraiseexcept(__status & FE_ALL_EXCEPT);
195	return (0);
196}
197
198#if __BSD_VISIBLE
199
200static __inline int
201fesetmask(int __mask)
202{
203	int __control;
204
205	__fnstcw(&__control);
206	__mask = (__control | FE_ALL_EXCEPT) & ~__mask;
207	__fldcw(__mask);
208	return (~__control & FE_ALL_EXCEPT);
209}
210
211static __inline int
212fegetmask(void)
213{
214	int __control;
215
216	__fnstcw(&__control);
217	return (~__control & FE_ALL_EXCEPT);
218}
219
220#endif /* __BSD_VISIBLE */
221
222__END_DECLS
223
224#endif	/* !_FENV_H_ */
225