text: /*
   * 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 "utils.h"
  
  #include <fenv.h>
  #include <stdint.h>
  
  static void TestRounding(float expectation1, float expectation2) {
    // Volatile to prevent compile-time evaluation.
    volatile float f = 1.968750f;
    volatile float m = 0x1.0p23f;
    float x;
    DoNotOptimize(x = f + m);
    ASSERT_FLOAT_EQ(expectation1, x);
    DoNotOptimize(x = x - m);
    ASSERT_EQ(expectation2, x);
  }
  
  static void DivideByZero() {
    // Volatile to prevent compile-time evaluation.
    volatile float zero = 0.0f;
    DoNotOptimize(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));
  }
  
  TEST(fenv, FE_DFL_ENV_macro) {
    ASSERT_EQ(0, fesetenv(FE_DFL_ENV));
  }
  
  TEST(fenv, feraiseexcept) {
    feclearexcept(FE_ALL_EXCEPT);
    ASSERT_EQ(0, fetestexcept(FE_ALL_EXCEPT));
  
    ASSERT_EQ(0, feraiseexcept(FE_DIVBYZERO | FE_OVERFLOW));
    ASSERT_EQ(FE_DIVBYZERO | FE_OVERFLOW, fetestexcept(FE_ALL_EXCEPT));
  }
  
  TEST(fenv, fegetenv_fesetenv) {
    // Set FE_OVERFLOW only.
    feclearexcept(FE_ALL_EXCEPT);
    ASSERT_EQ(0, fetestexcept(FE_ALL_EXCEPT));
    ASSERT_EQ(0, feraiseexcept(FE_OVERFLOW));
  
    // fegetenv (unlike feholdexcept) leaves the current state untouched...
    fenv_t state;
    ASSERT_EQ(0, fegetenv(&state));
    ASSERT_EQ(FE_OVERFLOW, fetestexcept(FE_ALL_EXCEPT));
  
    // Dividing by zero sets the appropriate flag...
    DivideByZero();
    ASSERT_EQ(FE_DIVBYZERO | FE_OVERFLOW, fetestexcept(FE_ALL_EXCEPT));
  
    // And fesetenv (unlike feupdateenv) clobbers that to return to where
    // we started.
    ASSERT_EQ(0, fesetenv(&state));
    ASSERT_EQ(FE_OVERFLOW, fetestexcept(FE_ALL_EXCEPT));
  }
  
  TEST(fenv, feholdexcept_feupdateenv) {
    // Set FE_OVERFLOW only.
    feclearexcept(FE_ALL_EXCEPT);
    ASSERT_EQ(0, fetestexcept(FE_ALL_EXCEPT));
    ASSERT_EQ(0, feraiseexcept(FE_OVERFLOW));
  
    // feholdexcept (unlike fegetenv) clears everything...
    fenv_t state;
    ASSERT_EQ(0, feholdexcept(&state));
    ASSERT_EQ(0, fetestexcept(FE_ALL_EXCEPT));
  
    // Dividing by zero sets the appropriate flag...
    DivideByZero();
    ASSERT_EQ(FE_DIVBYZERO, fetestexcept(FE_ALL_EXCEPT));
  
    // And feupdateenv (unlike fesetenv) merges what we started with
    // (FE_OVERFLOW) with what we now have (FE_DIVBYZERO).
    ASSERT_EQ(0, feupdateenv(&state));
    ASSERT_EQ(FE_DIVBYZERO | FE_OVERFLOW, fetestexcept(FE_ALL_EXCEPT));
  }
  
  TEST(fenv, fegetexceptflag_fesetexceptflag) {
    // Set three flags.
    feclearexcept(FE_ALL_EXCEPT);
    ASSERT_EQ(0, feraiseexcept(FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW));
    ASSERT_EQ(FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW, fetestexcept(FE_ALL_EXCEPT));
  
    fexcept_t all; // FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW
    fexcept_t two; // FE_OVERFLOW | FE_UNDERFLOW
    ASSERT_EQ(0, fegetexceptflag(&all, FE_ALL_EXCEPT));
    ASSERT_EQ(0, fegetexceptflag(&two, FE_OVERFLOW | FE_UNDERFLOW));
  
    // Check we can restore all.
    feclearexcept(FE_ALL_EXCEPT);
    ASSERT_EQ(0, fesetexceptflag(&all, FE_ALL_EXCEPT));
    ASSERT_EQ(FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW, fetestexcept(FE_ALL_EXCEPT));
  
    // Check that `two` only stored a subset.
    feclearexcept(FE_ALL_EXCEPT);
    ASSERT_EQ(0, fesetexceptflag(&two, FE_ALL_EXCEPT));
    ASSERT_EQ(FE_OVERFLOW | FE_UNDERFLOW, fetestexcept(FE_ALL_EXCEPT));
  
    // Check that we can restore a single flag.
    feclearexcept(FE_ALL_EXCEPT);
    ASSERT_EQ(0, fesetexceptflag(&all, FE_DIVBYZERO));
    ASSERT_EQ(FE_DIVBYZERO, fetestexcept(FE_ALL_EXCEPT));
  
    // Check that we can restore a subset of flags.
    feclearexcept(FE_ALL_EXCEPT);
    ASSERT_EQ(0, fesetexceptflag(&all, FE_OVERFLOW | FE_UNDERFLOW));
    ASSERT_EQ(FE_OVERFLOW | FE_UNDERFLOW, fetestexcept(FE_ALL_EXCEPT));
  }
  
  TEST(fenv, fedisableexcept_fegetexcept) {
    feclearexcept(FE_ALL_EXCEPT);
    ASSERT_EQ(0, fetestexcept(FE_ALL_EXCEPT));
  
    // No SIGFPE please...
    ASSERT_EQ(0, fedisableexcept(FE_ALL_EXCEPT));
    ASSERT_EQ(0, fegetexcept());
    ASSERT_EQ(0, feraiseexcept(FE_INVALID));
    ASSERT_EQ(FE_INVALID, fetestexcept(FE_ALL_EXCEPT));
  }
  
  TEST(fenv, feenableexcept_fegetexcept) {
  #if defined(__aarch64__) || defined(__arm__)
    // ARM doesn't support this. They used to if you go back far enough, but it was removed in
    // the Cortex-A8 between r3p1 and r3p2.
    ASSERT_EQ(-1, feenableexcept(FE_INVALID));
    ASSERT_EQ(0, fegetexcept());
    ASSERT_EQ(-1, feenableexcept(FE_DIVBYZERO));
    ASSERT_EQ(0, fegetexcept());
    ASSERT_EQ(-1, feenableexcept(FE_OVERFLOW));
    ASSERT_EQ(0, fegetexcept());
    ASSERT_EQ(-1, feenableexcept(FE_UNDERFLOW));
    ASSERT_EQ(0, fegetexcept());
    ASSERT_EQ(-1, feenableexcept(FE_INEXACT));
    ASSERT_EQ(0, fegetexcept());
    ASSERT_EQ(-1, feenableexcept(FE_DENORMAL));
    ASSERT_EQ(0, fegetexcept());
  #else
    // We can't recover from SIGFPE, so sacrifice a child...
    pid_t pid = fork();
    ASSERT_NE(-1, pid) << strerror(errno);
  
    if (pid == 0) {
      signal(SIGFPE, SIG_DFL);  // Disable debuggerd.
      feclearexcept(FE_ALL_EXCEPT);
      ASSERT_EQ(0, fetestexcept(FE_ALL_EXCEPT));
      ASSERT_EQ(0, feenableexcept(FE_INVALID));
      ASSERT_EQ(FE_INVALID, fegetexcept());
      ASSERT_EQ(0, feraiseexcept(FE_INVALID));
      _exit(123);
    }
  
    AssertChildExited(pid, -SIGFPE);
  #endif
  }
  