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/* This file is part of the dynarmic project.
* Copyright (c) 2018 MerryMage
* SPDX-License-Identifier: 0BSD
*/
#include <tuple>
#include <vector>
#include <catch2/catch_test_macros.hpp>
#include <mcl/stdint.hpp>
#include "../rand_int.h"
#include "dynarmic/common/fp/mantissa_util.h"
#include "dynarmic/common/safe_ops.h"
using namespace Dynarmic;
using namespace Dynarmic::FP;
TEST_CASE("ResidualErrorOnRightShift", "[fp]") {
const std::vector<std::tuple<u32, int, ResidualError>> test_cases{
{0x00000001, 1, ResidualError::Half},
{0x00000002, 1, ResidualError::Zero},
{0x00000001, 2, ResidualError::LessThanHalf},
{0x00000002, 2, ResidualError::Half},
{0x00000003, 2, ResidualError::GreaterThanHalf},
{0x00000004, 2, ResidualError::Zero},
{0x00000005, 2, ResidualError::LessThanHalf},
{0x00000006, 2, ResidualError::Half},
{0x00000007, 2, ResidualError::GreaterThanHalf},
};
for (auto [mantissa, shift, expected_result] : test_cases) {
const ResidualError result = ResidualErrorOnRightShift(mantissa, shift);
REQUIRE(result == expected_result);
}
}
TEST_CASE("ResidualErrorOnRightShift Randomized", "[fp]") {
for (size_t test = 0; test < 100000; test++) {
const u64 mantissa = mcl::bit::sign_extend<32, u64>(RandInt<u32>(0, 0xFFFFFFFF));
const int shift = RandInt<int>(-60, 60);
const ResidualError result = ResidualErrorOnRightShift(mantissa, shift);
const u64 calculated_error = Safe::ArithmeticShiftRightDouble(mantissa, u64(0), shift);
const ResidualError expected_result = [&] {
constexpr u64 half_error = 0x8000'0000'0000'0000ull;
if (calculated_error == 0) {
return ResidualError::Zero;
}
if (calculated_error < half_error) {
return ResidualError::LessThanHalf;
}
if (calculated_error == half_error) {
return ResidualError::Half;
}
return ResidualError::GreaterThanHalf;
}();
INFO(std::hex << "mantissa " << mantissa << " shift " << shift << " calculated_error " << calculated_error);
REQUIRE(result == expected_result);
}
}
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