1/* $OpenBSD: fenv.c,v 1.4 2022/12/27 17:10:07 jmc Exp $ */
2/*-
3 * Copyright (c) 2004-2005 David Schultz <das@FreeBSD.ORG>
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 *
27 * $FreeBSD: head/lib/msun/aarch64/fenv.h 280857 2015-03-30 16:42:08Z emaste $
28 */
29
30#include <fenv.h>
31#include <machine/ieeefp.h>
32
33#define	__get_fcsr(r)	asm volatile("frcsr %0" : "=r" (r))
34#define	__set_fcsr(r)	asm volatile("fscsr %0" : "+r" (r))
35#define	__get_flags(r)	asm volatile("frflags %0" : "=r" (r))
36#define	__set_flags(r)	asm volatile("fsflags %0" : "+r" (r))
37#define	__get_frm(r)	asm volatile("frrm %0" : "=r" (r))
38#define	__set_frm(r)	asm volatile("fsrm %0" : "+r"(r) )
39
40/*
41 * The following constant represents the default floating-point environment
42 * (that is, the one installed at program startup) and has type pointer to
43 * const-qualified fenv_t.
44 *
45 * It can be used as an argument to the functions within the <fenv.h> header
46 * that manage the floating-point environment, namely fesetenv() and
47 * feupdateenv().
48 */
49fenv_t __fe_dfl_env = 0;
50
51/*
52 * The feclearexcept() function clears the supported floating-point exceptions
53 * represented by `excepts'.
54 */
55int
56feclearexcept(int excepts)
57{
58	fexcept_t r;
59
60	excepts &= FE_ALL_EXCEPT;
61	__get_flags(r);
62	r &= ~excepts;
63	__set_flags(r);
64	return (0);
65}
66DEF_STD(feclearexcept);
67
68/*
69 * The fegetexceptflag() function stores an implementation-defined
70 * representation of the states of the floating-point status flags indicated by
71 * the argument excepts in the object pointed to by the argument flagp.
72 */
73int
74fegetexceptflag(fexcept_t *flagp, int excepts)
75{
76	fexcept_t r;
77
78	excepts &= FE_ALL_EXCEPT;
79	__get_flags(r);
80	*flagp = r & excepts;
81	return (0);
82}
83
84/*
85 * The feraiseexcept() function raises the supported floating-point exceptions
86 * represented by the argument `excepts'.
87 */
88int
89feraiseexcept(int excepts)
90{
91	fexcept_t r;
92
93	excepts &= FE_ALL_EXCEPT;
94	__get_flags(r);
95	r |= excepts;
96	__set_flags(r);
97	return (0);
98}
99DEF_STD(feraiseexcept);
100
101/*
102 * This function sets the floating-point status flags indicated by the argument
103 * `excepts' to the states stored in the object pointed to by `flagp'. It does
104 * NOT raise any floating-point exceptions, but only sets the state of the flags.
105 */
106int
107fesetexceptflag(const fexcept_t *flagp, int excepts)
108{
109	fexcept_t r;
110
111	excepts &= FE_ALL_EXCEPT;
112	__get_flags(r);
113	r &= ~excepts;
114	r |= *flagp & excepts;
115	__set_flags(r);
116	return (0);
117}
118DEF_STD(fesetexceptflag);
119
120/*
121 * The fetestexcept() function determines which of a specified subset of the
122 * floating-point exception flags are currently set. The `excepts' argument
123 * specifies the floating-point status flags to be queried.
124 */
125int
126fetestexcept(int excepts)
127{
128	fexcept_t r;
129
130	excepts &= FE_ALL_EXCEPT;
131	__get_flags(r);
132	return (r & excepts);
133}
134DEF_STD(fetestexcept);
135
136/*
137 * The fegetround() function gets the current rounding direction.
138 */
139int
140fegetround(void)
141{
142	fenv_t r;
143
144	__get_frm(r);
145	return (r & _ROUND_MASK);
146}
147DEF_STD(fegetround);
148
149/*
150 * The fesetround() function establishes the rounding direction represented by
151 * its argument `round'. If the argument is not equal to the value of a rounding
152 * direction macro, the rounding direction is not changed.
153 */
154int
155fesetround(int round)
156{
157	fenv_t r;
158
159	if (round & ~_ROUND_MASK)
160		return (-1);
161	__set_frm(round);
162	return (0);
163}
164DEF_STD(fesetround);
165
166/*
167 * The fegetenv() function attempts to store the current floating-point
168 * environment in the object pointed to by envp.
169 */
170int
171fegetenv(fenv_t *envp)
172{
173	fenv_t r;
174
175	__get_fcsr(r);
176	*envp = r;
177
178	return (0);
179}
180DEF_STD(fegetenv);
181
182/*
183 * The feholdexcept() function saves the current floating-point environment
184 * in the object pointed to by envp, clears the floating-point status flags, and
185 * then installs a non-stop (continue on floating-point exceptions) mode, if
186 * available, for all floating-point exceptions.
187 */
188int
189feholdexcept(fenv_t *envp)
190{
191	fenv_t r;
192
193	__get_fcsr(r);
194	*envp  = r;
195	r &= ~FE_ALL_EXCEPT;
196	__set_fcsr(r);
197
198	return (0);
199}
200DEF_STD(feholdexcept);
201
202/*
203 * The fesetenv() function attempts to establish the floating-point environment
204 * represented by the object pointed to by envp. The argument `envp' points
205 * to an object set by a call to fegetenv() or feholdexcept(), or equal a
206 * floating-point environment macro. The fesetenv() function does not raise
207 * floating-point exceptions, but only installs the state of the floating-point
208 * status flags represented through its argument.
209 */
210int
211fesetenv(const fenv_t *envp)
212{
213
214	fenv_t r;
215	r = *envp;
216	__set_fcsr(r);
217	return (0);
218}
219DEF_STD(fesetenv);
220
221/*
222 * The feupdateenv() function saves the currently raised floating-point
223 * exceptions in its automatic storage, installs the floating-point environment
224 * represented by the object pointed to by `envp', and then raises the saved
225 * floating-point exceptions. The argument `envp' shall point to an object set
226 * by a call to feholdexcept() or fegetenv(), or equal a floating-point
227 * environment macro.
228 */
229int
230feupdateenv(const fenv_t *envp)
231{
232	fexcept_t r;
233
234	__get_fcsr(r);
235	fesetenv(envp);
236	feraiseexcept(r & FE_ALL_EXCEPT);
237	return (0);
238}
239DEF_STD(feupdateenv);
240
241/*
242 * The following functions are extensions to the standard
243 */
244int
245feenableexcept(int mask)
246{
247	return -1;
248}
249
250int
251fedisableexcept(int mask)
252{
253	return 0;
254}
255
256int
257fegetexcept(void)
258{
259	return 0;
260}
261