1/*-
2 * Copyright (c) 2013 The NetBSD Foundation, Inc.
3 * All rights reserved.
4 *
5 * This code is derived from software contributed to The NetBSD Foundation
6 * by Matt Thomas of 3am Software Foundry.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
18 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
19 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
20 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
21 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
22 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
23 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
24 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
25 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
26 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
27 * POSSIBILITY OF SUCH DAMAGE.
28 */
29
30#include <sys/cdefs.h>
31__RCSID("$NetBSD: fenv.c,v 1.9 2017/05/08 09:25:03 martin Exp $");
32
33#include "namespace.h"
34
35#include <sys/types.h>
36#include <assert.h>
37#include <fenv.h>
38#include <string.h>
39#include <unistd.h>
40#include <inttypes.h>
41
42#ifdef __SOFTFP__
43#error This fenv implementation is only for hardfloat.
44#endif
45
46#ifdef __weak_alias
47__weak_alias(feclearexcept,_feclearexcept)
48__weak_alias(fedisableexcept,_fedisableexcept)
49__weak_alias(feenableexcept,_feenableexcept)
50__weak_alias(fegetenv,_fegetenv)
51__weak_alias(fegetexcept,_fegetexcept)
52__weak_alias(fegetexceptflag,_fegetexceptflag)
53__weak_alias(fegetround,_fegetround)
54__weak_alias(feholdexcept,_feholdexcept)
55__weak_alias(feraiseexcept,_feraiseexcept)
56__weak_alias(fesetenv,_fesetenv)
57__weak_alias(fesetexceptflag,_fesetexceptflag)
58__weak_alias(fesetround,_fesetround)
59__weak_alias(fetestexcept,_fetestexcept)
60__weak_alias(feupdateenv,_feupdateenv)
61#endif
62
63#include <arm/armreg.h>
64#include <arm/vfpreg.h>
65
66const fenv_t __fe_dfl_env = VFP_FPSCR_FZ|VFP_FPSCR_DN|VFP_FPSCR_RN;
67
68/*
69 * The feclearexcept() function shall attempt to clear the supported
70 * floating-point exceptions represented by excepts.
71 */
72int
73feclearexcept(int excepts)
74{
75#ifndef lint
76	_DIAGASSERT((except & ~FE_ALL_EXCEPT) == 0);
77#endif
78	int tmp = armreg_fpscr_read() & ~__SHIFTIN(excepts, VFP_FPSCR_CSUM);
79	armreg_fpscr_write(tmp);
80	return 0;
81}
82
83/*
84 * The fegetexceptflag() function shall attempt to store an
85 * implementation-defined representation of the states of the floating-point
86 * status flags indicated by the argument excepts in the object pointed to by
87 * the argument flagp.
88 */
89int
90fegetexceptflag(fexcept_t *flagp, int excepts)
91{
92
93	_DIAGASSERT((except & ~FE_ALL_EXCEPT) == 0);
94	*flagp = __SHIFTOUT(armreg_fpscr_read(), VFP_FPSCR_CSUM) & excepts;
95	return 0;
96}
97
98/*
99 * The feraiseexcept() function shall attempt to raise the supported
100 * floating-point exceptions represented by the argument excepts. The order
101 * in which these floating-point exceptions are raised is unspecified.
102 */
103int
104feraiseexcept(int excepts)
105{
106#ifndef lint
107	_DIAGASSERT((except & ~FE_ALL_EXCEPT) == 0);
108#endif
109	int fpscr = armreg_fpscr_read();
110	fpscr |= __SHIFTIN(excepts, VFP_FPSCR_CSUM);
111	armreg_fpscr_write(fpscr);
112	return 0;
113}
114
115/*
116 * The fesetexceptflag() function shall attempt to set the floating-point
117 * status flags indicated by the argument excepts to the states stored in the
118 * object pointed to by flagp. The value pointed to by flagp shall have been
119 * set by a previous call to fegetexceptflag() whose second argument
120 * represented at least those floating-point exceptions represented by the
121 * argument excepts. This function does not raise floating-point exceptions,
122 * but only sets the state of the flags.
123 */
124int
125fesetexceptflag(const fexcept_t *flagp, int excepts)
126{
127#ifndef lint
128	_DIAGASSERT((except & ~FE_ALL_EXCEPT) == 0);
129#endif
130	int fpscr = armreg_fpscr_read();
131	fpscr &= ~__SHIFTIN(excepts, VFP_FPSCR_CSUM);
132	fpscr |= __SHIFTIN((*flagp & excepts), VFP_FPSCR_CSUM);
133	armreg_fpscr_write(fpscr);
134	return 0;
135}
136
137int
138feenableexcept(int excepts)
139{
140#ifndef lint
141	_DIAGASSERT((except & ~FE_ALL_EXCEPT) == 0);
142#endif
143	int fpscr = armreg_fpscr_read();
144	armreg_fpscr_write(fpscr | __SHIFTIN((excepts), VFP_FPSCR_ESUM));
145	return __SHIFTOUT(fpscr, VFP_FPSCR_ESUM) & FE_ALL_EXCEPT;
146}
147
148int
149fedisableexcept(int excepts)
150{
151#ifndef lint
152	_DIAGASSERT((except & ~FE_ALL_EXCEPT) == 0);
153#endif
154	int fpscr = armreg_fpscr_read();
155	armreg_fpscr_write(fpscr & ~__SHIFTIN((excepts), VFP_FPSCR_ESUM));
156	return __SHIFTOUT(fpscr, VFP_FPSCR_ESUM) & FE_ALL_EXCEPT;
157}
158
159/*
160 * The fetestexcept() function shall determine which of a specified subset of
161 * the floating-point exception flags are currently set. The excepts argument
162 * specifies the floating-point status flags to be queried.
163 */
164int
165fetestexcept(int excepts)
166{
167	_DIAGASSERT((except & ~FE_ALL_EXCEPT) == 0);
168	return __SHIFTOUT(armreg_fpscr_read(), VFP_FPSCR_CSUM) & excepts;
169}
170
171int
172fegetexcept(void)
173{
174	return __SHIFTOUT(armreg_fpscr_read(), VFP_FPSCR_ESUM);
175}
176
177/*
178 * The fegetround() function shall get the current rounding direction.
179 */
180int
181fegetround(void)
182{
183	return __SHIFTOUT(armreg_fpscr_read(), VFP_FPSCR_RMODE);
184}
185
186/*
187 * The fesetround() function shall establish the rounding direction represented
188 * by its argument round. If the argument is not equal to the value of a
189 * rounding direction macro, the rounding direction is not changed.
190 */
191int
192fesetround(int round)
193{
194#ifndef lint
195	_DIAGASSERT(!(round & ~__SHIFTOUT(VFP_FPSCR_RMODE, VFP_FPSCR_RMODE)));
196#endif
197	int fpscr = armreg_fpscr_read() & ~VFP_FPSCR_RMODE;
198	fpscr |= __SHIFTIN(round, VFP_FPSCR_RMODE);
199	armreg_fpscr_write(fpscr);
200	return 0;
201}
202
203/*
204 * The fegetenv() function shall attempt to store the current floating-point
205 * environment in the object pointed to by envp.
206 */
207int
208fegetenv(fenv_t *envp)
209{
210
211	*envp = armreg_fpscr_read();
212	return 0;
213}
214
215/*
216 * The feholdexcept() function shall save the current floating-point
217 * environment in the object pointed to by envp, clear the floating-point
218 * status flags, and then install a non-stop (continue on floating-point
219 * exceptions) mode, if available, for all floating-point exceptions.
220 */
221int
222feholdexcept(fenv_t *envp)
223{
224
225	*envp = armreg_fpscr_read();
226	armreg_fpscr_write((*envp) & ~(VFP_FPSCR_ESUM|VFP_FPSCR_CSUM));
227	return 0;
228}
229
230/*
231 * The fesetenv() function shall attempt to establish the floating-point
232 * environment represented by the object pointed to by envp. The fesetenv()
233 * function does not raise floating-point exceptions, but only installs the
234 * state of the floating-point status flags represented through its argument.
235 */
236int
237fesetenv(const fenv_t *envp)
238{
239
240	armreg_fpscr_write(*envp);
241	return 0;
242}
243
244/*
245 * The feupdateenv() function shall attempt to save the currently raised
246 * floating-point exceptions in its automatic storage, attempt to install the
247 * floating-point environment represented by the object pointed to by envp,
248 * and then attempt to raise the saved floating-point exceptions.
249 */
250int
251feupdateenv(const fenv_t *envp)
252{
253#ifndef lint
254	_DIAGASSERT(envp != NULL);
255#endif
256	int fpscr = armreg_fpscr_read();
257	fpscr &= ~(VFP_FPSCR_ESUM|VFP_FPSCR_RMODE);
258	fpscr |= *envp;
259	armreg_fpscr_write(fpscr);
260
261	/* Success */
262	return 0;
263}
264