66 lines
2.5 KiB
C++
66 lines
2.5 KiB
C++
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// Copyright 2017 The Abseil Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include "absl/random/internal/wide_multiply.h"
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#include "gtest/gtest.h"
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#include "absl/numeric/int128.h"
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using absl::random_internal::MultiplyU64ToU128;
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namespace {
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TEST(WideMultiplyTest, MultiplyU64ToU128Test) {
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constexpr uint64_t k1 = 1;
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constexpr uint64_t kMax = ~static_cast<uint64_t>(0);
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EXPECT_EQ(absl::uint128(0), MultiplyU64ToU128(0, 0));
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// Max uint64_t
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EXPECT_EQ(MultiplyU64ToU128(kMax, kMax),
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absl::MakeUint128(0xfffffffffffffffe, 0x0000000000000001));
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EXPECT_EQ(absl::MakeUint128(0, kMax), MultiplyU64ToU128(kMax, 1));
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EXPECT_EQ(absl::MakeUint128(0, kMax), MultiplyU64ToU128(1, kMax));
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for (int i = 0; i < 64; ++i) {
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EXPECT_EQ(absl::MakeUint128(0, kMax) << i,
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MultiplyU64ToU128(kMax, k1 << i));
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EXPECT_EQ(absl::MakeUint128(0, kMax) << i,
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MultiplyU64ToU128(k1 << i, kMax));
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}
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// 1-bit x 1-bit.
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for (int i = 0; i < 64; ++i) {
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for (int j = 0; j < 64; ++j) {
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EXPECT_EQ(absl::MakeUint128(0, 1) << (i + j),
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MultiplyU64ToU128(k1 << i, k1 << j));
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EXPECT_EQ(absl::MakeUint128(0, 1) << (i + j),
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MultiplyU64ToU128(k1 << i, k1 << j));
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}
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}
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// Verified multiplies
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EXPECT_EQ(MultiplyU64ToU128(0xffffeeeeddddcccc, 0xbbbbaaaa99998888),
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absl::MakeUint128(0xbbbb9e2692c5dddc, 0xc28f7531048d2c60));
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EXPECT_EQ(MultiplyU64ToU128(0x0123456789abcdef, 0xfedcba9876543210),
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absl::MakeUint128(0x0121fa00ad77d742, 0x2236d88fe5618cf0));
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EXPECT_EQ(MultiplyU64ToU128(0x0123456789abcdef, 0xfdb97531eca86420),
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absl::MakeUint128(0x0120ae99d26725fc, 0xce197f0ecac319e0));
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EXPECT_EQ(MultiplyU64ToU128(0x97a87f4f261ba3f2, 0xfedcba9876543210),
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absl::MakeUint128(0x96fbf1a8ae78d0ba, 0x5a6dd4b71f278320));
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EXPECT_EQ(MultiplyU64ToU128(0xfedcba9876543210, 0xfdb97531eca86420),
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absl::MakeUint128(0xfc98c6981a413e22, 0x342d0bbf48948200));
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}
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} // namespace
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