1//===-- Utility class to test fixed-point sqrt ------------------*- 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 "test/UnitTest/Test.h"
10
11#include "src/__support/CPP/bit.h"
12#include "src/__support/FPUtil/BasicOperations.h"
13#include "src/__support/FPUtil/sqrt.h"
14#include "src/__support/fixed_point/fx_rep.h"
15#include "src/__support/fixed_point/sqrt.h"
16
17template <typename T> class SqrtTest : public LIBC_NAMESPACE::testing::Test {
18
19 using FXRep = LIBC_NAMESPACE::fixed_point::FXRep<T>;
20 static constexpr T zero = FXRep::ZERO();
21 static constexpr T min = FXRep::MIN();
22 static constexpr T max = FXRep::MAX();
23 static constexpr T half = static_cast<T>(0.5);
24 static constexpr T quarter = static_cast<T>(0.25);
25 static constexpr T one =
26 (FXRep::INTEGRAL_LEN > 0) ? static_cast<T>(1) : FXRep::MAX();
27 static constexpr T eps = FXRep::EPS();
28
29public:
30 typedef T (*SqrtFunc)(T);
31
32 void testSpecialNumbers(SqrtFunc func) {
33 EXPECT_EQ(zero, func(zero));
34 EXPECT_EQ(half, func(quarter));
35
36 if constexpr (FXRep::INTEGRAL_LEN) {
37 EXPECT_EQ(one, func(one));
38 EXPECT_EQ(static_cast<T>(2.0), func(static_cast<T>(4.0)));
39 }
40
41 using StorageType = typename FXRep::StorageType;
42
43 constexpr size_t COUNT = 255;
44 constexpr StorageType STEP =
45 StorageType(~StorageType(0)) / static_cast<StorageType>(COUNT);
46 constexpr double ERR = 3.0 * static_cast<double>(eps);
47 StorageType x = 0;
48 for (size_t i = 0; i < COUNT; ++i, x += STEP) {
49 T v = LIBC_NAMESPACE::cpp::bit_cast<T>(x);
50 double v_d = static_cast<double>(v);
51 double errors = LIBC_NAMESPACE::fputil::abs(
52 static_cast<double>(func(v)) -
53 LIBC_NAMESPACE::fputil::sqrt<double>(v_d));
54 if (errors > ERR) {
55 // Print out the failure input and output.
56 EXPECT_EQ(v, zero);
57 EXPECT_EQ(func(v), zero);
58 }
59 ASSERT_TRUE(errors <= ERR);
60 }
61 }
62};
63
64#define LIST_SQRT_TESTS(T, func) \
65 using LlvmLibcSqrtTest = SqrtTest<T>; \
66 TEST_F(LlvmLibcSqrtTest, SpecialNumbers) { testSpecialNumbers(&func); } \
67 static_assert(true, "Require semicolon.")
68

source code of libc/test/src/stdfix/SqrtTest.h