86 lines
2.9 KiB
C++
Executable File
86 lines
2.9 KiB
C++
Executable File
// SPDX-FileCopyrightText: Copyright 2023 yuzu Emulator Project
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// SPDX-License-Identifier: GPL-3.0-or-later
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#pragma once
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#include "common/alignment.h"
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#include "common/common_types.h"
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namespace VideoCommon {
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class UsageTracker {
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static constexpr size_t BYTES_PER_BIT_SHIFT = 6;
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static constexpr size_t PAGE_SHIFT = 6 + BYTES_PER_BIT_SHIFT;
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static constexpr size_t PAGE_BYTES = 1 << PAGE_SHIFT;
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public:
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explicit UsageTracker(size_t size) {
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const size_t num_pages = (size >> PAGE_SHIFT) + 1;
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pages.resize(num_pages, 0ULL);
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}
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void Reset() noexcept {
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std::ranges::fill(pages, 0ULL);
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}
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void Track(u64 offset, u64 size) noexcept {
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const size_t page = offset >> PAGE_SHIFT;
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const size_t page_end = (offset + size) >> PAGE_SHIFT;
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if (page_end < page || page_end >= pages.size()) {
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return;
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}
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TrackPage(page, offset, size);
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if (page == page_end) {
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return;
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}
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for (size_t i = page + 1; i < page_end; i++) {
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pages[i] = ~u64{0};
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}
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const size_t offset_end = offset + size;
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const size_t offset_end_page_aligned = Common::AlignDown(offset_end, PAGE_BYTES);
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TrackPage(page_end, offset_end_page_aligned, offset_end - offset_end_page_aligned);
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}
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[[nodiscard]] bool IsUsed(u64 offset, u64 size) const noexcept {
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const size_t page = offset >> PAGE_SHIFT;
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const size_t page_end = (offset + size) >> PAGE_SHIFT;
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if (page_end < page || page_end >= pages.size()) {
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return false;
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}
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if (IsPageUsed(page, offset, size)) {
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return true;
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}
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for (size_t i = page + 1; i < page_end; i++) {
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if (pages[i] != 0) {
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return true;
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}
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}
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const size_t offset_end = offset + size;
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const size_t offset_end_page_aligned = Common::AlignDown(offset_end, PAGE_BYTES);
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return IsPageUsed(page_end, offset_end_page_aligned, offset_end - offset_end_page_aligned);
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}
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private:
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void TrackPage(u64 page, u64 offset, u64 size) noexcept {
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const size_t offset_in_page = offset % PAGE_BYTES;
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const size_t first_bit = offset_in_page >> BYTES_PER_BIT_SHIFT;
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const size_t num_bits = std::min<size_t>(size, PAGE_BYTES) >> BYTES_PER_BIT_SHIFT;
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const size_t mask = ~u64{0} >> (64 - num_bits);
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pages[page] |= (~u64{0} & mask) << first_bit;
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}
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bool IsPageUsed(u64 page, u64 offset, u64 size) const noexcept {
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const size_t offset_in_page = offset % PAGE_BYTES;
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const size_t first_bit = offset_in_page >> BYTES_PER_BIT_SHIFT;
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const size_t num_bits = std::min<size_t>(size, PAGE_BYTES) >> BYTES_PER_BIT_SHIFT;
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const size_t mask = ~u64{0} >> (64 - num_bits);
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const size_t mask2 = (~u64{0} & mask) << first_bit;
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return (pages[page] & mask2) != 0;
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}
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private:
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std::vector<u64> pages;
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};
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} // namespace VideoCommon
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