1 /*
2 * Copyright (C) 2012 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include <gtest/gtest.h>
18
19 #include "utils.h"
20
21 #include <fenv.h>
22 #include <stdint.h>
23
TestRounding(float expectation1,float expectation2)24 static void TestRounding(float expectation1, float expectation2) {
25 // Volatile to prevent compile-time evaluation.
26 volatile float f = 1.968750f;
27 volatile float m = 0x1.0p23f;
28 float x;
29 DoNotOptimize(x = f + m);
30 ASSERT_FLOAT_EQ(expectation1, x);
31 DoNotOptimize(x = x - m);
32 ASSERT_EQ(expectation2, x);
33 }
34
DivideByZero()35 static void DivideByZero() {
36 // Volatile to prevent compile-time evaluation.
37 volatile float zero = 0.0f;
38 DoNotOptimize(123.0f / zero);
39 }
40
TEST(fenv,fesetround_fegetround_FE_TONEAREST)41 TEST(fenv, fesetround_fegetround_FE_TONEAREST) {
42 fesetround(FE_TONEAREST);
43 ASSERT_EQ(FE_TONEAREST, fegetround());
44 TestRounding(8388610.0f, 2.0f);
45 }
46
TEST(fenv,fesetround_fegetround_FE_TOWARDZERO)47 TEST(fenv, fesetround_fegetround_FE_TOWARDZERO) {
48 fesetround(FE_TOWARDZERO);
49 ASSERT_EQ(FE_TOWARDZERO, fegetround());
50 TestRounding(8388609.0f, 1.0f);
51 }
52
TEST(fenv,fesetround_fegetround_FE_UPWARD)53 TEST(fenv, fesetround_fegetround_FE_UPWARD) {
54 fesetround(FE_UPWARD);
55 ASSERT_EQ(FE_UPWARD, fegetround());
56 TestRounding(8388610.0f, 2.0f);
57 }
58
TEST(fenv,fesetround_fegetround_FE_DOWNWARD)59 TEST(fenv, fesetround_fegetround_FE_DOWNWARD) {
60 fesetround(FE_DOWNWARD);
61 ASSERT_EQ(FE_DOWNWARD, fegetround());
62 TestRounding(8388609.0f, 1.0f);
63 }
64
TEST(fenv,feclearexcept_fetestexcept)65 TEST(fenv, feclearexcept_fetestexcept) {
66 // Clearing clears.
67 feclearexcept(FE_ALL_EXCEPT);
68 ASSERT_EQ(0, fetestexcept(FE_ALL_EXCEPT));
69
70 // Dividing by zero sets FE_DIVBYZERO.
71 DivideByZero();
72 int raised = fetestexcept(FE_DIVBYZERO | FE_OVERFLOW);
73 ASSERT_TRUE((raised & FE_OVERFLOW) == 0);
74 ASSERT_TRUE((raised & FE_DIVBYZERO) != 0);
75
76 // Clearing an unset bit is a no-op.
77 feclearexcept(FE_OVERFLOW);
78 ASSERT_TRUE((raised & FE_OVERFLOW) == 0);
79 ASSERT_TRUE((raised & FE_DIVBYZERO) != 0);
80
81 // Clearing a set bit works.
82 feclearexcept(FE_DIVBYZERO);
83 ASSERT_EQ(0, fetestexcept(FE_ALL_EXCEPT));
84 }
85
TEST(fenv,FE_DFL_ENV_macro)86 TEST(fenv, FE_DFL_ENV_macro) {
87 ASSERT_EQ(0, fesetenv(FE_DFL_ENV));
88 }
89
TEST(fenv,feraiseexcept)90 TEST(fenv, feraiseexcept) {
91 feclearexcept(FE_ALL_EXCEPT);
92 ASSERT_EQ(0, fetestexcept(FE_ALL_EXCEPT));
93
94 ASSERT_EQ(0, feraiseexcept(FE_DIVBYZERO | FE_OVERFLOW));
95 ASSERT_EQ(FE_DIVBYZERO | FE_OVERFLOW, fetestexcept(FE_ALL_EXCEPT));
96 }
97
TEST(fenv,fegetenv_fesetenv)98 TEST(fenv, fegetenv_fesetenv) {
99 // Set FE_OVERFLOW only.
100 feclearexcept(FE_ALL_EXCEPT);
101 ASSERT_EQ(0, fetestexcept(FE_ALL_EXCEPT));
102 ASSERT_EQ(0, feraiseexcept(FE_OVERFLOW));
103
104 // fegetenv (unlike feholdexcept) leaves the current state untouched...
105 fenv_t state;
106 ASSERT_EQ(0, fegetenv(&state));
107 ASSERT_EQ(FE_OVERFLOW, fetestexcept(FE_ALL_EXCEPT));
108
109 // Dividing by zero sets the appropriate flag...
110 DivideByZero();
111 ASSERT_EQ(FE_DIVBYZERO | FE_OVERFLOW, fetestexcept(FE_ALL_EXCEPT));
112
113 // And fesetenv (unlike feupdateenv) clobbers that to return to where
114 // we started.
115 ASSERT_EQ(0, fesetenv(&state));
116 ASSERT_EQ(FE_OVERFLOW, fetestexcept(FE_ALL_EXCEPT));
117 }
118
TEST(fenv,feholdexcept_feupdateenv)119 TEST(fenv, feholdexcept_feupdateenv) {
120 // Set FE_OVERFLOW only.
121 feclearexcept(FE_ALL_EXCEPT);
122 ASSERT_EQ(0, fetestexcept(FE_ALL_EXCEPT));
123 ASSERT_EQ(0, feraiseexcept(FE_OVERFLOW));
124
125 // feholdexcept (unlike fegetenv) clears everything...
126 fenv_t state;
127 ASSERT_EQ(0, feholdexcept(&state));
128 ASSERT_EQ(0, fetestexcept(FE_ALL_EXCEPT));
129
130 // Dividing by zero sets the appropriate flag...
131 DivideByZero();
132 ASSERT_EQ(FE_DIVBYZERO, fetestexcept(FE_ALL_EXCEPT));
133
134 // And feupdateenv (unlike fesetenv) merges what we started with
135 // (FE_OVERFLOW) with what we now have (FE_DIVBYZERO).
136 ASSERT_EQ(0, feupdateenv(&state));
137 ASSERT_EQ(FE_DIVBYZERO | FE_OVERFLOW, fetestexcept(FE_ALL_EXCEPT));
138 }
139
TEST(fenv,fegetexceptflag_fesetexceptflag)140 TEST(fenv, fegetexceptflag_fesetexceptflag) {
141 // Set three flags.
142 feclearexcept(FE_ALL_EXCEPT);
143 ASSERT_EQ(0, feraiseexcept(FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW));
144 ASSERT_EQ(FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW, fetestexcept(FE_ALL_EXCEPT));
145
146 fexcept_t all; // FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW
147 fexcept_t two; // FE_OVERFLOW | FE_UNDERFLOW
148 ASSERT_EQ(0, fegetexceptflag(&all, FE_ALL_EXCEPT));
149 ASSERT_EQ(0, fegetexceptflag(&two, FE_OVERFLOW | FE_UNDERFLOW));
150
151 // Check we can restore all.
152 feclearexcept(FE_ALL_EXCEPT);
153 ASSERT_EQ(0, fesetexceptflag(&all, FE_ALL_EXCEPT));
154 ASSERT_EQ(FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW, fetestexcept(FE_ALL_EXCEPT));
155
156 // Check that `two` only stored a subset.
157 feclearexcept(FE_ALL_EXCEPT);
158 ASSERT_EQ(0, fesetexceptflag(&two, FE_ALL_EXCEPT));
159 ASSERT_EQ(FE_OVERFLOW | FE_UNDERFLOW, fetestexcept(FE_ALL_EXCEPT));
160
161 // Check that we can restore a single flag.
162 feclearexcept(FE_ALL_EXCEPT);
163 ASSERT_EQ(0, fesetexceptflag(&all, FE_DIVBYZERO));
164 ASSERT_EQ(FE_DIVBYZERO, fetestexcept(FE_ALL_EXCEPT));
165
166 // Check that we can restore a subset of flags.
167 feclearexcept(FE_ALL_EXCEPT);
168 ASSERT_EQ(0, fesetexceptflag(&all, FE_OVERFLOW | FE_UNDERFLOW));
169 ASSERT_EQ(FE_OVERFLOW | FE_UNDERFLOW, fetestexcept(FE_ALL_EXCEPT));
170 }
171
TEST(fenv,fedisableexcept_fegetexcept)172 TEST(fenv, fedisableexcept_fegetexcept) {
173 feclearexcept(FE_ALL_EXCEPT);
174 ASSERT_EQ(0, fetestexcept(FE_ALL_EXCEPT));
175
176 // No SIGFPE please...
177 ASSERT_EQ(0, fedisableexcept(FE_ALL_EXCEPT));
178 ASSERT_EQ(0, fegetexcept());
179 ASSERT_EQ(0, feraiseexcept(FE_INVALID));
180 ASSERT_EQ(FE_INVALID, fetestexcept(FE_ALL_EXCEPT));
181 }
182
TEST(fenv,feenableexcept_fegetexcept)183 TEST(fenv, feenableexcept_fegetexcept) {
184 #if defined(__aarch64__) || defined(__arm__)
185 // ARM doesn't support this. They used to if you go back far enough, but it was removed in
186 // the Cortex-A8 between r3p1 and r3p2.
187 ASSERT_EQ(-1, feenableexcept(FE_INVALID));
188 ASSERT_EQ(0, fegetexcept());
189 ASSERT_EQ(-1, feenableexcept(FE_DIVBYZERO));
190 ASSERT_EQ(0, fegetexcept());
191 ASSERT_EQ(-1, feenableexcept(FE_OVERFLOW));
192 ASSERT_EQ(0, fegetexcept());
193 ASSERT_EQ(-1, feenableexcept(FE_UNDERFLOW));
194 ASSERT_EQ(0, fegetexcept());
195 ASSERT_EQ(-1, feenableexcept(FE_INEXACT));
196 ASSERT_EQ(0, fegetexcept());
197 ASSERT_EQ(-1, feenableexcept(FE_DENORMAL));
198 ASSERT_EQ(0, fegetexcept());
199 #else
200 // We can't recover from SIGFPE, so sacrifice a child...
201 pid_t pid = fork();
202 ASSERT_NE(-1, pid) << strerror(errno);
203
204 if (pid == 0) {
205 signal(SIGFPE, SIG_DFL); // Disable debuggerd.
206 feclearexcept(FE_ALL_EXCEPT);
207 ASSERT_EQ(0, fetestexcept(FE_ALL_EXCEPT));
208 ASSERT_EQ(0, feenableexcept(FE_INVALID));
209 ASSERT_EQ(FE_INVALID, fegetexcept());
210 ASSERT_EQ(0, feraiseexcept(FE_INVALID));
211 _exit(123);
212 }
213
214 AssertChildExited(pid, -SIGFPE);
215 #endif
216 }
217