1/*-
2 * Copyright (c) 2004-2005 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: src/lib/msun/alpha/fenv.h,v 1.3 2005/03/16 19:03:44 das Exp $
27 */
28
29#ifndef	_FENV_H_
30#define	_FENV_H_
31
32#include <sys/_types.h>
33
34typedef	__uint64_t	fenv_t;
35typedef	__uint16_t	fexcept_t;
36
37/* Exception flags */
38#define	FE_INVALID	0x02
39#define	FE_DIVBYZERO	0x04
40#define	FE_OVERFLOW	0x08
41#define	FE_UNDERFLOW	0x10
42#define	FE_INEXACT	0x20
43#define	FE_INTOVF	0x40	/* not maskable */
44#define	FE_ALL_EXCEPT	(FE_DIVBYZERO | FE_INEXACT | FE_INTOVF | \
45			 FE_INVALID | FE_OVERFLOW | FE_UNDERFLOW)
46
47/* Rounding modes */
48#define	FE_TOWARDZERO	0x00
49#define	FE_DOWNWARD	0x01
50#define	FE_TONEAREST	0x02
51#define	FE_UPWARD	0x03
52#define	_ROUND_MASK	(FE_TONEAREST | FE_DOWNWARD | \
53			 FE_UPWARD | FE_TOWARDZERO)
54#define	_ROUND_SHIFT	58
55
56#define	_FPUSW_SHIFT	51
57
58#define	__excb()	__asm __volatile("excb")
59#define	__mf_fpcr(__cw)	__asm __volatile("mf_fpcr %0" : "=f" (*(__cw)))
60#define	__mt_fpcr(__cw)	__asm __volatile("mt_fpcr %0" : : "f" (__cw))
61
62union __fpcr {
63	double __d;
64	fenv_t __bits;
65};
66
67__BEGIN_DECLS
68
69/* Default floating-point environment */
70extern const fenv_t	__fe_dfl_env;
71#define	FE_DFL_ENV	(&__fe_dfl_env)
72
73static __inline int
74feclearexcept(int __excepts)
75{
76	union __fpcr __r;
77
78	__excb();
79	__mf_fpcr(&__r.__d);
80	__r.__bits &= ~((fenv_t)__excepts << _FPUSW_SHIFT);
81	__mt_fpcr(__r.__d);
82	__excb();
83	return (0);
84}
85
86static __inline int
87fegetexceptflag(fexcept_t *__flagp, int __excepts)
88{
89	union __fpcr __r;
90
91	__excb();
92	__mf_fpcr(&__r.__d);
93	__excb();
94	*__flagp = (__r.__bits >> _FPUSW_SHIFT) & __excepts;
95	return (0);
96}
97
98static __inline int
99fesetexceptflag(const fexcept_t *__flagp, int __excepts)
100{
101	union __fpcr __r;
102	fenv_t __xflag, __xexcepts;
103
104	__xflag = (fenv_t)*__flagp << _FPUSW_SHIFT;
105	__xexcepts = (fenv_t)__excepts << _FPUSW_SHIFT;
106	__excb();
107	__mf_fpcr(&__r.__d);
108	__r.__bits &= ~__xexcepts;
109	__r.__bits |= __xflag & __xexcepts;
110	__mt_fpcr(__r.__d);
111	__excb();
112	return (0);
113}
114
115static __inline int
116feraiseexcept(int __excepts)
117{
118
119	/*
120	 * XXX Generating exceptions this way does not actually invoke
121	 * a userland trap handler when enabled, but neither do
122	 * arithmetic operations as far as I can tell.  Perhaps there
123	 * are more bugs in the kernel trap handler.
124	 */
125	fexcept_t __ex = __excepts;
126	fesetexceptflag(&__ex, __excepts);
127	return (0);
128}
129
130static __inline int
131fetestexcept(int __excepts)
132{
133	union __fpcr __r;
134
135	__excb();
136	__mf_fpcr(&__r.__d);
137	__excb();
138	return ((__r.__bits >> _FPUSW_SHIFT) & __excepts);
139}
140
141static __inline int
142fegetround(void)
143{
144	union __fpcr __r;
145
146	/*
147	 * No exception barriers should be required here if we assume
148	 * that only fesetround() can change the rounding mode.
149	 */
150	__mf_fpcr(&__r.__d);
151	return ((int)(__r.__bits >> _ROUND_SHIFT) & _ROUND_MASK);
152}
153
154static __inline int
155fesetround(int __round)
156{
157	union __fpcr __r;
158
159	if (__round & ~_ROUND_MASK)
160		return (-1);
161	__excb();
162	__mf_fpcr(&__r.__d);
163	__r.__bits &= ~((fenv_t)_ROUND_MASK << _ROUND_SHIFT);
164	__r.__bits |= (fenv_t)__round << _ROUND_SHIFT;
165	__mt_fpcr(__r.__d);
166	__excb();
167	return (0);
168}
169
170int	fegetenv(fenv_t *__envp);
171int	feholdexcept(fenv_t *__envp);
172int	fesetenv(const fenv_t *__envp);
173int	feupdateenv(const fenv_t *__envp);
174
175#if __BSD_VISIBLE
176
177int	feenableexcept(int __mask);
178int	fedisableexcept(int __mask);
179int	fegetexcept(void);
180
181#endif /* __BSD_VISIBLE */
182
183__END_DECLS
184
185#endif	/* !_FENV_H_ */
186