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