xref: /aosp_15_r20/external/llvm-libc/test/src/stdfix/FxBitsTest.h (revision 71db0c75aadcf003ffe3238005f61d7618a3fead)
1 //===-- Utility class to test int to fixed point conversions ----*- 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 "include/llvm-libc-types/stdfix-types.h"
12 #include "src/__support/CPP/bit.h"
13 #include "src/__support/fixed_point/fx_bits.h"
14 
15 template <typename T, typename XType>
16 class FxBitsTest : public LIBC_NAMESPACE::testing::Test {
17   using FXRep = LIBC_NAMESPACE::fixed_point::FXRep<T>;
18   static constexpr T zero = FXRep::ZERO();
19   static constexpr T min = FXRep::MIN();
20   static constexpr T max = FXRep::MAX();
21   static constexpr T half = static_cast<T>(0.5);
22   static constexpr T quarter = static_cast<T>(0.25);
23   static constexpr T one =
24       (FXRep::INTEGRAL_LEN > 0) ? static_cast<T>(1) : FXRep::MAX();
25   static constexpr T eps = FXRep::EPS();
get_one_or_saturated_fraction()26   constexpr XType get_one_or_saturated_fraction() {
27     if (FXRep::INTEGRAL_LEN > 0) {
28       return static_cast<XType>(static_cast<XType>(0x1) << FXRep::FRACTION_LEN);
29     } else {
30       return static_cast<XType>(
31           LIBC_NAMESPACE::mask_trailing_ones<typename FXRep::StorageType,
32                                              FXRep::FRACTION_LEN>());
33     }
34   }
35 
36 public:
37   typedef T (*FxBitsFunc)(XType);
38 
test_special_numbers(FxBitsFunc func)39   void test_special_numbers(FxBitsFunc func) {
40     EXPECT_EQ(zero, func(0));
41     EXPECT_EQ(eps, func(0x1));
42     // x.1000...
43     EXPECT_EQ(half, func(static_cast<XType>(0x1) << (FXRep::FRACTION_LEN - 1)));
44     // Occupy the bit to the left of the fixed point for Accum types
45     // Saturate fraction portion for Fract types
46     EXPECT_EQ(one, func(get_one_or_saturated_fraction()));
47   }
48 };
49 
50 #define LIST_FXBITS_TEST(Name, T, XType, func)                                 \
51   using LlvmLibc##Name##BitsTest = FxBitsTest<T, XType>;                       \
52   TEST_F(LlvmLibc##Name##BitsTest, SpecialNumbers) {                           \
53     test_special_numbers(&func);                                               \
54   }                                                                            \
55   static_assert(true, "Require semicolon.")
56