75 lines
2.0 KiB
C++
75 lines
2.0 KiB
C++
// This file is part of Eigen, a lightweight C++ template library
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// for linear algebra.
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//
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// Copyright (C) 2023 The Eigen Authors
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//
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// This Source Code Form is subject to the terms of the Mozilla
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// Public License v. 2.0. If a copy of the MPL was not distributed
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// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
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#include "main.h"
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template <typename T>
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int ref_clz(T val) {
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constexpr int kNumBits = sizeof(T) * CHAR_BIT;
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T kMsbMask = T(1) << (kNumBits - 1);
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int z = 0;
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for (; z < kNumBits && ((val & kMsbMask) == 0); ++z) {
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val <<= 1;
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}
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return z;
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}
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template <typename T>
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int ref_ctz(T val) {
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constexpr int kNumBits = sizeof(T) * CHAR_BIT;
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T kLsbMask = T(1);
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int z = 0;
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for (; z < kNumBits && ((val & kLsbMask) == 0); ++z) {
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val >>= 1;
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}
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return z;
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}
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template <typename T>
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void test_clz_ctz() {
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T step = sizeof(T) <= 2 ? 1 : (Eigen::NumTraits<T>::highest() / (T(1) << 16));
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T iters = Eigen::NumTraits<T>::highest() / step;
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for (T i = 0; i < iters; ++i) {
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T val = i * step;
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int expected_clz = ref_clz(val);
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int actual_clz = Eigen::internal::clz(val);
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VERIFY(expected_clz == actual_clz);
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int expected_ctz = ref_ctz(val);
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int actual_ctz = Eigen::internal::ctz(val);
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VERIFY(expected_ctz == actual_ctz);
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}
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}
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template <typename T>
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void test_clz_ctz_random() {
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for (int i = 0; i < 1024 * 1024; ++i) {
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T val = Eigen::internal::random<T>();
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int expected_clz = ref_clz(val);
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int actual_clz = Eigen::internal::clz(val);
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VERIFY(expected_clz == actual_clz);
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int expected_ctz = ref_ctz(val);
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int actual_ctz = Eigen::internal::ctz(val);
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VERIFY(expected_ctz == actual_ctz);
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}
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}
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EIGEN_DECLARE_TEST(clz) {
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CALL_SUBTEST_1(test_clz_ctz<uint8_t>());
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CALL_SUBTEST_2(test_clz_ctz<uint16_t>());
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CALL_SUBTEST_3(test_clz_ctz<uint32_t>());
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CALL_SUBTEST_4(test_clz_ctz<uint64_t>());
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for (int i = 0; i < g_repeat; i++) {
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test_clz_ctz_random<uint32_t>();
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test_clz_ctz_random<uint64_t>();
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}
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}
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