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 * $FreeBSD$
27 */
28
29#ifndef	_FENV_H_
30#define	_FENV_H_
31
32#include <stdint.h>
33#include <sys/cdefs.h>
34#include <sys/types.h>
35
36#ifndef	__fenv_static
37#define	__fenv_static	static
38#endif
39
40typedef	uint64_t	fenv_t;
41typedef	uint64_t	fexcept_t;
42
43/* Exception flags */
44#define	FE_INVALID	0x00000001
45#define	FE_DIVBYZERO	0x00000002
46#define	FE_OVERFLOW	0x00000004
47#define	FE_UNDERFLOW	0x00000008
48#define	FE_INEXACT	0x00000010
49#define	FE_ALL_EXCEPT	(FE_DIVBYZERO | FE_INEXACT | \
50			 FE_INVALID | FE_OVERFLOW | FE_UNDERFLOW)
51
52/*
53 * Rounding modes
54 *
55 * We can't just use the hardware bit values here, because that would
56 * make FE_UPWARD and FE_DOWNWARD negative, which is not allowed.
57 */
58#define	FE_TONEAREST	0x0
59#define	FE_UPWARD	0x1
60#define	FE_DOWNWARD	0x2
61#define	FE_TOWARDZERO	0x3
62#define	_ROUND_MASK	(FE_TONEAREST | FE_DOWNWARD | \
63			 FE_UPWARD | FE_TOWARDZERO)
64#define	_ROUND_SHIFT	22
65
66__BEGIN_DECLS
67
68/* Default floating-point environment */
69extern const fenv_t	__fe_dfl_env;
70#define	FE_DFL_ENV	(&__fe_dfl_env)
71
72/* We need to be able to map status flag positions to mask flag positions */
73#define _FPUSW_SHIFT	8
74#define	_ENABLE_MASK	(FE_ALL_EXCEPT << _FPUSW_SHIFT)
75
76#define	__mrs_fpcr(__r)	__asm __volatile("mrs %0, fpcr" : "=r" (__r))
77#define	__msr_fpcr(__r)	__asm __volatile("msr fpcr, %0" : : "r" (__r))
78
79#define	__mrs_fpsr(__r)	__asm __volatile("mrs %0, fpsr" : "=r" (__r))
80#define	__msr_fpsr(__r)	__asm __volatile("msr fpsr, %0" : : "r" (__r))
81
82__fenv_static __inline int
83feclearexcept(int __excepts)
84{
85	fexcept_t __r;
86
87	__mrs_fpsr(__r);
88	__r &= ~__excepts;
89	__msr_fpsr(__r);
90	return (0);
91}
92
93__fenv_static inline int
94fegetexceptflag(fexcept_t *__flagp, int __excepts)
95{
96	fexcept_t __r;
97
98	__mrs_fpsr(__r);
99	*__flagp = __r & __excepts;
100	return (0);
101}
102
103__fenv_static inline int
104fesetexceptflag(const fexcept_t *__flagp, int __excepts)
105{
106	fexcept_t __r;
107
108	__mrs_fpsr(__r);
109	__r &= ~__excepts;
110	__r |= *__flagp & __excepts;
111	__msr_fpsr(__r);
112	return (0);
113}
114
115__fenv_static inline int
116feraiseexcept(int __excepts)
117{
118	fexcept_t __r;
119
120	__mrs_fpsr(__r);
121	__r |= __excepts;
122	__msr_fpsr(__r);
123	return (0);
124}
125
126__fenv_static inline int
127fetestexcept(int __excepts)
128{
129	fexcept_t __r;
130
131	__mrs_fpsr(__r);
132	return (__r & __excepts);
133}
134
135__fenv_static inline int
136fegetround(void)
137{
138	fenv_t __r;
139
140	__mrs_fpcr(__r);
141	return ((__r >> _ROUND_SHIFT) & _ROUND_MASK);
142}
143
144__fenv_static inline int
145fesetround(int __round)
146{
147	fenv_t __r;
148
149	if (__round & ~_ROUND_MASK)
150		return (-1);
151	__mrs_fpcr(__r);
152	__r &= ~(_ROUND_MASK << _ROUND_SHIFT);
153	__r |= __round << _ROUND_SHIFT;
154	__msr_fpcr(__r);
155	return (0);
156}
157
158__fenv_static inline int
159fegetenv(fenv_t *__envp)
160{
161	fenv_t __r;
162
163	__mrs_fpcr(__r);
164	*__envp = __r & _ENABLE_MASK;
165
166	__mrs_fpsr(__r);
167	*__envp |= __r & (FE_ALL_EXCEPT | (_ROUND_MASK << _ROUND_SHIFT));
168
169	return (0);
170}
171
172__fenv_static inline int
173feholdexcept(fenv_t *__envp)
174{
175	fenv_t __r;
176
177	__mrs_fpcr(__r);
178	*__envp = __r & _ENABLE_MASK;
179	__r &= ~(_ENABLE_MASK);
180	__msr_fpcr(__r);
181
182	__mrs_fpsr(__r);
183	*__envp |= __r & (FE_ALL_EXCEPT | (_ROUND_MASK << _ROUND_SHIFT));
184	__r &= ~(_ENABLE_MASK);
185	__msr_fpsr(__r);
186	return (0);
187}
188
189__fenv_static inline int
190fesetenv(const fenv_t *__envp)
191{
192
193	__msr_fpcr((*__envp) & _ENABLE_MASK);
194	__msr_fpsr((*__envp) & (FE_ALL_EXCEPT | (_ROUND_MASK << _ROUND_SHIFT)));
195	return (0);
196}
197
198__fenv_static inline int
199feupdateenv(const fenv_t *__envp)
200{
201	fexcept_t __r;
202
203	__mrs_fpsr(__r);
204	fesetenv(__envp);
205	feraiseexcept(__r & FE_ALL_EXCEPT);
206	return (0);
207}
208
209#if __BSD_VISIBLE
210
211/* We currently provide no external definitions of the functions below. */
212
213static inline int
214feenableexcept(int __mask)
215{
216	fenv_t __old_r, __new_r;
217
218	__mrs_fpcr(__old_r);
219	__new_r = __old_r | ((__mask & FE_ALL_EXCEPT) << _FPUSW_SHIFT);
220	__msr_fpcr(__new_r);
221	return ((__old_r >> _FPUSW_SHIFT) & FE_ALL_EXCEPT);
222}
223
224static inline int
225fedisableexcept(int __mask)
226{
227	fenv_t __old_r, __new_r;
228
229	__mrs_fpcr(__old_r);
230	__new_r = __old_r & ~((__mask & FE_ALL_EXCEPT) << _FPUSW_SHIFT);
231	__msr_fpcr(__new_r);
232	return ((__old_r >> _FPUSW_SHIFT) & FE_ALL_EXCEPT);
233}
234
235static inline int
236fegetexcept(void)
237{
238	fenv_t __r;
239
240	__mrs_fpcr(__r);
241	return ((__r & _ENABLE_MASK) >> _FPUSW_SHIFT);
242}
243
244#endif /* __BSD_VISIBLE */
245
246__END_DECLS
247
248#endif	/* !_FENV_H_ */
249