xref: /freebsd/lib/msun/riscv/fenv.h (revision 12913e4ddf710e517f3ae00b7b420b783cca9b37)
1 /*-
2  * Copyright (c) 2004-2005 David Schultz <das@FreeBSD.ORG>
3  * Copyright (c) 2015-2016 Ruslan Bukin <br@bsdpad.com>
4  * All rights reserved.
5  *
6  * Portions of this software were developed by SRI International and the
7  * University of Cambridge Computer Laboratory under DARPA/AFRL contract
8  * FA8750-10-C-0237 ("CTSRD"), as part of the DARPA CRASH research programme.
9  *
10  * Portions of this software were developed by the University of Cambridge
11  * Computer Laboratory as part of the CTSRD Project, with support from the
12  * UK Higher Education Innovation Fund (HEIF).
13  *
14  * Redistribution and use in source and binary forms, with or without
15  * modification, are permitted provided that the following conditions
16  * are met:
17  * 1. Redistributions of source code must retain the above copyright
18  *    notice, this list of conditions and the following disclaimer.
19  * 2. Redistributions in binary form must reproduce the above copyright
20  *    notice, this list of conditions and the following disclaimer in the
21  *    documentation and/or other materials provided with the distribution.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  */
35 
36 #ifndef	_FENV_H_
37 #define	_FENV_H_
38 
39 #include <sys/cdefs.h>
40 #include <sys/_types.h>
41 
42 #ifndef	__fenv_static
43 #define	__fenv_static	static
44 #endif
45 
46 typedef	__uint64_t	fenv_t;
47 typedef	__uint64_t	fexcept_t;
48 
49 /* Exception flags */
50 #define	FE_INVALID	0x0010
51 #define	FE_DIVBYZERO	0x0008
52 #define	FE_OVERFLOW	0x0004
53 #define	FE_UNDERFLOW	0x0002
54 #define	FE_INEXACT	0x0001
55 #define	FE_ALL_EXCEPT	(FE_DIVBYZERO | FE_INEXACT | \
56 			 FE_INVALID | FE_OVERFLOW | FE_UNDERFLOW)
57 
58 /*
59  * RISC-V Rounding modes
60  */
61 #define	_ROUND_SHIFT	5
62 #define	FE_TONEAREST	(0x00 << _ROUND_SHIFT)
63 #define	FE_TOWARDZERO	(0x01 << _ROUND_SHIFT)
64 #define	FE_DOWNWARD	(0x02 << _ROUND_SHIFT)
65 #define	FE_UPWARD	(0x03 << _ROUND_SHIFT)
66 #define	_ROUND_MASK	(FE_TONEAREST | FE_DOWNWARD | \
67 			 FE_UPWARD | FE_TOWARDZERO)
68 
69 __BEGIN_DECLS
70 
71 /* Default floating-point environment */
72 extern const fenv_t	__fe_dfl_env;
73 #define	FE_DFL_ENV	(&__fe_dfl_env)
74 
75 #ifndef __riscv_float_abi_double
76 #error only double hard float ABI supported
77 #endif
78 
79 #define	__rfs(__fcsr)	__asm __volatile("csrr %0, fcsr" : "=r" (__fcsr))
80 #define	__wfs(__fcsr)	__asm __volatile("csrw fcsr, %0" :: "r" (__fcsr))
81 
82 __fenv_static inline int
feclearexcept(int __excepts)83 feclearexcept(int __excepts)
84 {
85 
86 	__asm __volatile("csrc fflags, %0" :: "r"(__excepts));
87 
88 	return (0);
89 }
90 
91 __fenv_static inline int
fegetexceptflag(fexcept_t * __flagp,int __excepts)92 fegetexceptflag(fexcept_t *__flagp, int __excepts)
93 {
94 	fexcept_t __fcsr;
95 
96 	__rfs(__fcsr);
97 	*__flagp = __fcsr & __excepts;
98 
99 	return (0);
100 }
101 
102 __fenv_static inline int
fesetexceptflag(const fexcept_t * __flagp,int __excepts)103 fesetexceptflag(const fexcept_t *__flagp, int __excepts)
104 {
105 	fexcept_t __fcsr;
106 
107 	__fcsr = *__flagp;
108 	__asm __volatile("csrc fflags, %0" :: "r"(__excepts));
109 	__asm __volatile("csrs fflags, %0" :: "r"(__fcsr & __excepts));
110 
111 	return (0);
112 }
113 
114 __fenv_static inline int
feraiseexcept(int __excepts)115 feraiseexcept(int __excepts)
116 {
117 
118 	__asm __volatile("csrs fflags, %0" :: "r"(__excepts));
119 
120 	return (0);
121 }
122 
123 __fenv_static inline int
fetestexcept(int __excepts)124 fetestexcept(int __excepts)
125 {
126 	fexcept_t __fcsr;
127 
128 	__rfs(__fcsr);
129 
130 	return (__fcsr & __excepts);
131 }
132 
133 __fenv_static inline int
fegetround(void)134 fegetround(void)
135 {
136 	fexcept_t __fcsr;
137 
138 	__rfs(__fcsr);
139 
140 	return (__fcsr & _ROUND_MASK);
141 }
142 
143 __fenv_static inline int
fesetround(int __round)144 fesetround(int __round)
145 {
146 	fexcept_t __fcsr;
147 
148 	if (__round & ~_ROUND_MASK)
149 		return (-1);
150 
151 	__rfs(__fcsr);
152 	__fcsr &= ~_ROUND_MASK;
153 	__fcsr |= __round;
154 	__wfs(__fcsr);
155 
156 	return (0);
157 }
158 
159 __fenv_static inline int
fegetenv(fenv_t * __envp)160 fegetenv(fenv_t *__envp)
161 {
162 
163 	__rfs(*__envp);
164 
165 	return (0);
166 }
167 
168 __fenv_static inline int
feholdexcept(fenv_t * __envp __unused)169 feholdexcept(fenv_t *__envp __unused)
170 {
171 
172 	/* No exception traps. */
173 
174 	return (-1);
175 }
176 
177 __fenv_static inline int
fesetenv(const fenv_t * __envp)178 fesetenv(const fenv_t *__envp)
179 {
180 
181 	__wfs(*__envp);
182 
183 	return (0);
184 }
185 
186 __fenv_static inline int
feupdateenv(const fenv_t * __envp)187 feupdateenv(const fenv_t *__envp)
188 {
189 	fexcept_t __fcsr;
190 
191 	__rfs(__fcsr);
192 	__wfs(*__envp);
193 	feraiseexcept(__fcsr & FE_ALL_EXCEPT);
194 
195 	return (0);
196 }
197 
198 #if __BSD_VISIBLE
199 
200 __fenv_static inline int
feenableexcept(int __mask __unused)201 feenableexcept(int __mask __unused)
202 {
203 
204 	/* No exception traps. */
205 
206 	return (0);
207 }
208 
209 __fenv_static inline int
fedisableexcept(int __mask __unused)210 fedisableexcept(int __mask __unused)
211 {
212 
213 	/* No exception traps. */
214 
215 	return (0);
216 }
217 
218 /* We currently provide no external definition of fegetexcept(). */
219 static inline int
fegetexcept(void)220 fegetexcept(void)
221 {
222 
223 	/* No exception traps. */
224 
225 	return (0);
226 }
227 
228 #endif /* __BSD_VISIBLE */
229 
230 __END_DECLS
231 
232 #endif	/* !_FENV_H_ */
233