Rewrite <fenv.h> for ARM.

The old code was one big no-op.

Bug: http://code.google.com/p/android/issues/detail?id=38196
Change-Id: I201a6ffa477385b2629f45e8c948bdfbd47b5bf1

1 files changed, 81 insertions, 0 deletions

diff --git a/tests/fenv_test.cpp b/tests/fenv_test.cpp
new file mode 100644
index 000000000..4adb06658
--- /dev/null
+++ b/tests/fenv_test.cpp
@@ -0,0 +1,81 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <gtest/gtest.h>
+
+#include <fenv.h>
+#include <stdint.h>
+
+static void TestRounding(float expectation1, float expectation2) {
+  // volatile to prevent compiler optimizations.
+  volatile float f = 1.968750f;
+  volatile float m = 0x1.0p23f;
+  volatile float x = f + m;
+  ASSERT_FLOAT_EQ(expectation1, x);
+  x -= m;
+  ASSERT_EQ(expectation2, x);
+}
+
+static void DivideByZero() {
+  // volatile to prevent compiler optimizations.
+  volatile float zero = 0.0f;
+  volatile float result __attribute__((unused)) = 123.0f / zero;
+}
+
+TEST(fenv, fesetround_fegetround_FE_TONEAREST) {
+  fesetround(FE_TONEAREST);
+  ASSERT_EQ(FE_TONEAREST, fegetround());
+  TestRounding(8388610.0f, 2.0f);
+}
+
+TEST(fenv, fesetround_fegetround_FE_TOWARDZERO) {
+  fesetround(FE_TOWARDZERO);
+  ASSERT_EQ(FE_TOWARDZERO, fegetround());
+  TestRounding(8388609.0f, 1.0f);
+}
+
+TEST(fenv, fesetround_fegetround_FE_UPWARD) {
+  fesetround(FE_UPWARD);
+  ASSERT_EQ(FE_UPWARD, fegetround());
+  TestRounding(8388610.0f, 2.0f);
+}
+
+TEST(fenv, fesetround_fegetround_FE_DOWNWARD) {
+  fesetround(FE_DOWNWARD);
+  ASSERT_EQ(FE_DOWNWARD, fegetround());
+  TestRounding(8388609.0f, 1.0f);
+}
+
+TEST(fenv, feclearexcept_fetestexcept) {
+  // Clearing clears.
+  feclearexcept(FE_ALL_EXCEPT);
+  ASSERT_EQ(0, fetestexcept(FE_ALL_EXCEPT));
+
+  // Dividing by zero sets FE_DIVBYZERO.
+  DivideByZero();
+  int raised = fetestexcept(FE_DIVBYZERO | FE_OVERFLOW);
+  ASSERT_TRUE((raised & FE_OVERFLOW) == 0);
+  ASSERT_TRUE((raised & FE_DIVBYZERO) != 0);
+
+  // Clearing an unset bit is a no-op.
+  feclearexcept(FE_OVERFLOW);
+  ASSERT_TRUE((raised & FE_OVERFLOW) == 0);
+  ASSERT_TRUE((raised & FE_DIVBYZERO) != 0);
+
+  // Clearing a set bit works.
+  feclearexcept(FE_DIVBYZERO);
+  ASSERT_EQ(0, fetestexcept(FE_ALL_EXCEPT));
+}