libc/test/src/math/FrexpTest.h

   1 //===-- Utility class to test frexp[f|l] ------------------------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "src/__support/FPUtil/BasicOperations.h"
  10 #include "test/UnitTest/FEnvSafeTest.h"
  11 #include "test/UnitTest/FPMatcher.h"
  12 #include "test/UnitTest/Test.h"
  13 #include "utils/MPFRWrapper/MPFRUtils.h"
  14
  15 #include "hdr/math_macros.h"
  16
  17 namespace mpfr = LIBC_NAMESPACE::testing::mpfr;
  18
  19 template <typename T>
  20 class FrexpTest : public LIBC_NAMESPACE::testing::FEnvSafeTest {
  21
  22   DECLARE_SPECIAL_CONSTANTS(T)
  23
  24   static constexpr StorageType HIDDEN_BIT =
  25       StorageType(1) << LIBC_NAMESPACE::fputil::FPBits<T>::FRACTION_LEN;
  26
  27 public:
  28   typedef T (*FrexpFunc)(T, int *);
  29
  30   void testSpecialNumbers(FrexpFunc func) {
  31     int exponent;
  32     ASSERT_FP_EQ(aNaN, func(aNaN, &exponent));
  33     ASSERT_FP_EQ(inf, func(inf, &exponent));
  34     ASSERT_FP_EQ(neg_inf, func(neg_inf, &exponent));
  35
  36     ASSERT_FP_EQ(0.0, func(0.0, &exponent));
  37     ASSERT_EQ(exponent, 0);
  38
  39     ASSERT_FP_EQ(-0.0, func(-0.0, &exponent));
  40     ASSERT_EQ(exponent, 0);
  41   }
  42
  43   void testPowersOfTwo(FrexpFunc func) {
  44     int exponent;
  45
  46     EXPECT_FP_EQ(T(0.5), func(T(1.0), &exponent));
  47     EXPECT_EQ(exponent, 1);
  48     EXPECT_FP_EQ(T(-0.5), func(T(-1.0), &exponent));
  49     EXPECT_EQ(exponent, 1);
  50
  51     EXPECT_FP_EQ(T(0.5), func(T(2.0), &exponent));
  52     EXPECT_EQ(exponent, 2);
  53     EXPECT_FP_EQ(T(-0.5), func(T(-2.0), &exponent));
  54     EXPECT_EQ(exponent, 2);
  55
  56     EXPECT_FP_EQ(T(0.5), func(T(4.0), &exponent));
  57     EXPECT_EQ(exponent, 3);
  58     EXPECT_FP_EQ(T(-0.5), func(T(-4.0), &exponent));
  59     EXPECT_EQ(exponent, 3);
  60
  61     EXPECT_FP_EQ(T(0.5), func(T(8.0), &exponent));
  62     EXPECT_EQ(exponent, 4);
  63     EXPECT_FP_EQ(T(-0.5), func(T(-8.0), &exponent));
  64     EXPECT_EQ(exponent, 4);
  65
  66     EXPECT_FP_EQ(T(0.5), func(T(16.0), &exponent));
  67     EXPECT_EQ(exponent, 5);
  68     EXPECT_FP_EQ(T(-0.5), func(T(-16.0), &exponent));
  69     EXPECT_EQ(exponent, 5);
  70
  71     EXPECT_FP_EQ(T(0.5), func(T(32.0), &exponent));
  72     EXPECT_EQ(exponent, 6);
  73     EXPECT_FP_EQ(T(-0.5), func(T(-32.0), &exponent));
  74     EXPECT_EQ(exponent, 6);
  75   }
  76
  77   void testSomeIntegers(FrexpFunc func) {
  78     int exponent;
  79
  80     EXPECT_FP_EQ(T(0.75), func(T(24.0), &exponent));
  81     EXPECT_EQ(exponent, 5);
  82     EXPECT_FP_EQ(T(-0.75), func(T(-24.0), &exponent));
  83     EXPECT_EQ(exponent, 5);
  84
  85     EXPECT_FP_EQ(T(0.625), func(T(40.0), &exponent));
  86     EXPECT_EQ(exponent, 6);
  87     EXPECT_FP_EQ(T(-0.625), func(T(-40.0), &exponent));
  88     EXPECT_EQ(exponent, 6);
  89
  90     EXPECT_FP_EQ(T(0.78125), func(T(800.0), &exponent));
  91     EXPECT_EQ(exponent, 10);
  92     EXPECT_FP_EQ(T(-0.78125), func(T(-800.0), &exponent));
  93     EXPECT_EQ(exponent, 10);
  94   }
  95
  96   void testRange(FrexpFunc func) {
  97     using StorageType = typename FPBits::StorageType;
  98     constexpr StorageType COUNT = 100'000;
  99     constexpr StorageType STEP = STORAGE_MAX / COUNT;
 100     for (StorageType i = 0, v = 0; i <= COUNT; ++i, v += STEP) {
 101       T x = FPBits(v).get_val();
 102       if (FPBits(v).is_nan() || FPBits(v).is_inf() || x == 0.0l)
 103         continue;
 104
 105       mpfr::BinaryOutput<T> result;
 106       result.f = func(x, &result.i);
 107
 108       ASSERT_TRUE(LIBC_NAMESPACE::fputil::abs(result.f) < 1.0);
 109       ASSERT_TRUE(LIBC_NAMESPACE::fputil::abs(result.f) >= 0.5);
 110       ASSERT_MPFR_MATCH(mpfr::Operation::Frexp, x, result, 0.0);
 111     }
 112   }
 113 };
 114
 115 #define LIST_FREXP_TESTS(T, func)                                              \
 116   using LlvmLibcFrexpTest = FrexpTest<T>;                                      \
 117   TEST_F(LlvmLibcFrexpTest, SpecialNumbers) { testSpecialNumbers(&func); }     \
 118   TEST_F(LlvmLibcFrexpTest, PowersOfTwo) { testPowersOfTwo(&func); }           \
 119   TEST_F(LlvmLibcFrexpTest, SomeIntegers) { testSomeIntegers(&func); }         \
 120   TEST_F(LlvmLibcFrexpTest, InRange) { testRange(&func); }