1 //===-- Utility class to test different flavors of ilogb --------*- 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 #ifndef LLVM_LIBC_TEST_SRC_MATH_ILOGBTEST_H
10 #define LLVM_LIBC_TEST_SRC_MATH_ILOGBTEST_H
11 
12 #include "utils/FPUtil/FPBits.h"
13 #include "utils/FPUtil/ManipulationFunctions.h"
14 #include "utils/UnitTest/Test.h"
15 #include <math.h>
16 
17 #include <limits.h>
18 
19 class LlvmLibcILogbTest : public __llvm_libc::testing::Test {
20 public:
21   template <typename T> struct ILogbFunc { typedef int (*Func)(T); };
22 
23   template <typename T>
24   void testSpecialNumbers(typename ILogbFunc<T>::Func func) {
25     EXPECT_EQ(FP_ILOGB0, func(T(__llvm_libc::fputil::FPBits<T>::zero())));
26     EXPECT_EQ(FP_ILOGB0, func(T(__llvm_libc::fputil::FPBits<T>::negZero())));
27 
28     EXPECT_EQ(FP_ILOGBNAN,
29               func(T(__llvm_libc::fputil::FPBits<T>::buildNaN(1))));
30 
31     EXPECT_EQ(INT_MAX, func(T(__llvm_libc::fputil::FPBits<T>::inf())));
32     EXPECT_EQ(INT_MAX, func(T(__llvm_libc::fputil::FPBits<T>::negInf())));
33   }
34 
35   template <typename T> void testPowersOfTwo(typename ILogbFunc<T>::Func func) {
36     EXPECT_EQ(0, func(T(1.0)));
37     EXPECT_EQ(0, func(T(-1.0)));
38 
39     EXPECT_EQ(1, func(T(2.0)));
40     EXPECT_EQ(1, func(T(-2.0)));
41 
42     EXPECT_EQ(2, func(T(4.0)));
43     EXPECT_EQ(2, func(T(-4.0)));
44 
45     EXPECT_EQ(3, func(T(8.0)));
46     EXPECT_EQ(3, func(-8.0));
47 
48     EXPECT_EQ(4, func(16.0));
49     EXPECT_EQ(4, func(-16.0));
50 
51     EXPECT_EQ(5, func(32.0));
52     EXPECT_EQ(5, func(-32.0));
53   }
54 
55   template <typename T>
56   void testSomeIntegers(typename ILogbFunc<T>::Func func) {
57     EXPECT_EQ(1, func(T(3.0)));
58     EXPECT_EQ(1, func(T(-3.0)));
59 
60     EXPECT_EQ(2, func(T(7.0)));
61     EXPECT_EQ(2, func(T(-7.0)));
62 
63     EXPECT_EQ(3, func(T(10.0)));
64     EXPECT_EQ(3, func(T(-10.0)));
65 
66     EXPECT_EQ(4, func(T(31.0)));
67     EXPECT_EQ(4, func(-31.0));
68 
69     EXPECT_EQ(5, func(55.0));
70     EXPECT_EQ(5, func(-55.0));
71   }
72 
73   template <typename T>
74   void testSubnormalRange(typename ILogbFunc<T>::Func func) {
75     using FPBits = __llvm_libc::fputil::FPBits<T>;
76     using UIntType = typename FPBits::UIntType;
77     constexpr UIntType count = 1000001;
78     constexpr UIntType step =
79         (FPBits::maxSubnormal - FPBits::minSubnormal) / count;
80     for (UIntType v = FPBits::minSubnormal; v <= FPBits::maxSubnormal;
81          v += step) {
82       T x = T(FPBits(v));
83       if (isnan(x) || isinf(x) || x == 0.0)
84         continue;
85 
86       int exponent;
87       __llvm_libc::fputil::frexp(x, exponent);
88       ASSERT_EQ(exponent, func(x) + 1);
89     }
90   }
91 
92   template <typename T> void testNormalRange(typename ILogbFunc<T>::Func func) {
93     using FPBits = __llvm_libc::fputil::FPBits<T>;
94     using UIntType = typename FPBits::UIntType;
95     constexpr UIntType count = 1000001;
96     constexpr UIntType step = (FPBits::maxNormal - FPBits::minNormal) / count;
97     for (UIntType v = FPBits::minNormal; v <= FPBits::maxNormal; v += step) {
98       T x = T(FPBits(v));
99       if (isnan(x) || isinf(x) || x == 0.0)
100         continue;
101 
102       int exponent;
103       __llvm_libc::fputil::frexp(x, exponent);
104       ASSERT_EQ(exponent, func(x) + 1);
105     }
106   }
107 };
108 
109 #endif // LLVM_LIBC_TEST_SRC_MATH_ILOGBTEST_H
110