1 //===-- Unittests for frexp -----------------------------------------------===//
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/math/frexp.h"
10 #include "utils/FPUtil/BasicOperations.h"
11 #include "utils/FPUtil/BitPatterns.h"
12 #include "utils/FPUtil/ClassificationFunctions.h"
13 #include "utils/FPUtil/FPBits.h"
14 #include "utils/FPUtil/FloatOperations.h"
15 #include "utils/FPUtil/FloatProperties.h"
16 #include "utils/MPFRWrapper/MPFRUtils.h"
17 #include "utils/UnitTest/Test.h"
18 #include <math.h>
19 
20 using FPBits = __llvm_libc::fputil::FPBits<double>;
21 using __llvm_libc::fputil::valueAsBits;
22 using __llvm_libc::fputil::valueFromBits;
23 
24 namespace mpfr = __llvm_libc::testing::mpfr;
25 
26 using BitPatterns = __llvm_libc::fputil::BitPatterns<double>;
27 using Properties = __llvm_libc::fputil::FloatProperties<double>;
28 
29 TEST(LlvmLibcFrexpTest, SpecialNumbers) {
30   int exponent;
31 
32   EXPECT_EQ(BitPatterns::aQuietNaN,
33             valueAsBits(__llvm_libc::frexp(
34                 valueFromBits(BitPatterns::aQuietNaN), &exponent)));
35   EXPECT_EQ(BitPatterns::aNegativeQuietNaN,
36             valueAsBits(__llvm_libc::frexp(
37                 valueFromBits(BitPatterns::aNegativeQuietNaN), &exponent)));
38 
39   EXPECT_EQ(BitPatterns::aSignallingNaN,
40             valueAsBits(__llvm_libc::frexp(
41                 valueFromBits(BitPatterns::aSignallingNaN), &exponent)));
42   EXPECT_EQ(
43       BitPatterns::aNegativeSignallingNaN,
44       valueAsBits(__llvm_libc::frexp(
45           valueFromBits(BitPatterns::aNegativeSignallingNaN), &exponent)));
46 
47   EXPECT_EQ(BitPatterns::inf, valueAsBits(__llvm_libc::frexp(
48                                   valueFromBits(BitPatterns::inf), &exponent)));
49   EXPECT_EQ(BitPatterns::negInf,
50             valueAsBits(__llvm_libc::frexp(valueFromBits(BitPatterns::negInf),
51                                            &exponent)));
52 
53   EXPECT_EQ(BitPatterns::zero,
54             valueAsBits(__llvm_libc::frexp(valueFromBits(BitPatterns::zero),
55                                            &exponent)));
56   EXPECT_EQ(exponent, 0);
57   EXPECT_EQ(BitPatterns::negZero,
58             valueAsBits(__llvm_libc::frexp(valueFromBits(BitPatterns::negZero),
59                                            &exponent)));
60   EXPECT_EQ(exponent, 0);
61 }
62 
63 TEST(LlvmLibcFrexpTest, PowersOfTwo) {
64   int exponent;
65 
66   EXPECT_EQ(valueAsBits(0.5), valueAsBits(__llvm_libc::frexp(1.0, &exponent)));
67   EXPECT_EQ(exponent, 1);
68   EXPECT_EQ(valueAsBits(-0.5),
69             valueAsBits(__llvm_libc::frexp(-1.0, &exponent)));
70   EXPECT_EQ(exponent, 1);
71 
72   EXPECT_EQ(valueAsBits(0.5), valueAsBits(__llvm_libc::frexp(2.0, &exponent)));
73   EXPECT_EQ(exponent, 2);
74   EXPECT_EQ(valueAsBits(-0.5),
75             valueAsBits(__llvm_libc::frexp(-2.0, &exponent)));
76   EXPECT_EQ(exponent, 2);
77 
78   EXPECT_EQ(valueAsBits(0.5), valueAsBits(__llvm_libc::frexp(4.0, &exponent)));
79   EXPECT_EQ(exponent, 3);
80   EXPECT_EQ(valueAsBits(-0.5),
81             valueAsBits(__llvm_libc::frexp(-4.0, &exponent)));
82   EXPECT_EQ(exponent, 3);
83 
84   EXPECT_EQ(valueAsBits(0.5), valueAsBits(__llvm_libc::frexp(8.0, &exponent)));
85   EXPECT_EQ(exponent, 4);
86   EXPECT_EQ(valueAsBits(-0.5),
87             valueAsBits(__llvm_libc::frexp(-8.0, &exponent)));
88   EXPECT_EQ(exponent, 4);
89 
90   EXPECT_EQ(valueAsBits(0.5), valueAsBits(__llvm_libc::frexp(16.0, &exponent)));
91   EXPECT_EQ(exponent, 5);
92   EXPECT_EQ(valueAsBits(-0.5),
93             valueAsBits(__llvm_libc::frexp(-16.0, &exponent)));
94   EXPECT_EQ(exponent, 5);
95 
96   EXPECT_EQ(valueAsBits(0.5), valueAsBits(__llvm_libc::frexp(32.0, &exponent)));
97   EXPECT_EQ(exponent, 6);
98   EXPECT_EQ(valueAsBits(-0.5),
99             valueAsBits(__llvm_libc::frexp(-32.0, &exponent)));
100   EXPECT_EQ(exponent, 6);
101 
102   EXPECT_EQ(valueAsBits(0.5), valueAsBits(__llvm_libc::frexp(64.0, &exponent)));
103   EXPECT_EQ(exponent, 7);
104   EXPECT_EQ(valueAsBits(-0.5),
105             valueAsBits(__llvm_libc::frexp(-64.0, &exponent)));
106   EXPECT_EQ(exponent, 7);
107 }
108 
109 TEST(LlvmLibcFrexpTest, SomeIntegers) {
110   int exponent;
111 
112   EXPECT_EQ(valueAsBits(0.75),
113             valueAsBits(__llvm_libc::frexp(24.0, &exponent)));
114   EXPECT_EQ(exponent, 5);
115   EXPECT_EQ(valueAsBits(-0.75),
116             valueAsBits(__llvm_libc::frexp(-24.0, &exponent)));
117   EXPECT_EQ(exponent, 5);
118 
119   EXPECT_EQ(valueAsBits(0.625),
120             valueAsBits(__llvm_libc::frexp(40.0, &exponent)));
121   EXPECT_EQ(exponent, 6);
122   EXPECT_EQ(valueAsBits(-0.625),
123             valueAsBits(__llvm_libc::frexp(-40.0, &exponent)));
124   EXPECT_EQ(exponent, 6);
125 
126   EXPECT_EQ(valueAsBits(0.78125),
127             valueAsBits(__llvm_libc::frexp(800.0, &exponent)));
128   EXPECT_EQ(exponent, 10);
129   EXPECT_EQ(valueAsBits(-0.78125),
130             valueAsBits(__llvm_libc::frexp(-800.0, &exponent)));
131   EXPECT_EQ(exponent, 10);
132 }
133 
134 TEST(LlvmLibcFrexpTest, InDoubleRange) {
135   using UIntType = FPBits::UIntType;
136   constexpr UIntType count = 1000001;
137   constexpr UIntType step = UIntType(-1) / count;
138   for (UIntType i = 0, v = 0; i <= count; ++i, v += step) {
139     double x = FPBits(v);
140     if (isnan(x) || isinf(x) || x == 0.0)
141       continue;
142 
143     mpfr::BinaryOutput<double> result;
144     result.f = __llvm_libc::frexp(x, &result.i);
145 
146     ASSERT_TRUE(__llvm_libc::fputil::abs(result.f) < 1.0);
147     ASSERT_TRUE(__llvm_libc::fputil::abs(result.f) >= 0.5);
148     ASSERT_MPFR_MATCH(mpfr::Operation::Frexp, x, result, 0.0);
149   }
150 }
151