99 lines
No EOL
2.4 KiB
C++
99 lines
No EOL
2.4 KiB
C++
/**
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******************************************************************************
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* Xenia : Xbox 360 Emulator Research Project *
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******************************************************************************
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* Copyright 2015 Ben Vanik. All rights reserved. *
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* Released under the BSD license - see LICENSE in the root for more details. *
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******************************************************************************
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*
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* @modified Tom Clay, 2026 - Adapted for ReXGlue runtime
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*/
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#include <rex/assert.h>
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#include <rex/bit.h>
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#include <rex/math.h>
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#include <rex/thread/atomic.h>
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namespace rex::bit {
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BitMap::BitMap() = default;
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BitMap::BitMap(size_t size_bits) {
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Resize(size_bits);
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}
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BitMap::BitMap(uint64_t* data, size_t size_bits) {
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assert_true(size_bits % kDataSizeBits == 0);
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data_.resize(size_bits / kDataSizeBits);
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std::memcpy(data_.data(), data, size_bits / kDataSizeBits);
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}
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size_t BitMap::Acquire() {
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for (size_t i = 0; i < data_.size(); i++) {
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uint64_t entry = 0;
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uint64_t new_entry = 0;
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int64_t acquired_idx = -1;
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do {
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entry = data_[i];
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uint8_t index = lzcnt(entry);
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if (index == kDataSizeBits) {
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// None free.
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acquired_idx = -1;
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break;
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}
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// Entry has a free bit. Acquire it.
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uint64_t bit = 1ull << (kDataSizeBits - index - 1);
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new_entry = entry & ~bit;
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assert_not_zero(entry & bit);
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acquired_idx = index;
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} while (!thread::atomic_cas(entry, new_entry, &data_[i]));
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if (acquired_idx != -1) {
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// Acquired.
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return (i * kDataSizeBits) + acquired_idx;
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}
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}
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return -1;
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}
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void BitMap::Release(size_t index) {
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auto slot = index / kDataSizeBits;
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index -= slot * kDataSizeBits;
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uint64_t bit = 1ull << (kDataSizeBits - index - 1);
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uint64_t entry = 0;
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uint64_t new_entry = 0;
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do {
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entry = data_[slot];
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assert_zero(entry & bit);
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new_entry = entry | bit;
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} while (!thread::atomic_cas(entry, new_entry, &data_[slot]));
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}
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void BitMap::Resize(size_t new_size_bits) {
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auto old_size = data_.size();
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assert_true(new_size_bits % kDataSizeBits == 0);
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data_.resize(new_size_bits / kDataSizeBits);
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// Initialize new entries.
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if (data_.size() > old_size) {
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for (size_t i = old_size; i < data_.size(); i++) {
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data_[i] = -1;
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}
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}
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}
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void BitMap::Reset() {
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for (size_t i = 0; i < data_.size(); i++) {
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data_[i] = -1;
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}
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}
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} // namespace rex::bit
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