From ab20598c99fb5a4f160408c0b869602e1816faea Mon Sep 17 00:00:00 2001 From: Lander Gallastegi Date: Tue, 3 Jun 2025 22:28:48 +0200 Subject: [PATCH] Bit array test --- CMakeLists.txt | 1 + src/common/bit_array.h | 184 +++++++++++++++++++++++++++++++++++++++++ 2 files changed, 185 insertions(+) create mode 100644 src/common/bit_array.h diff --git a/CMakeLists.txt b/CMakeLists.txt index 09fddb3d7..44e3c9852 100644 --- a/CMakeLists.txt +++ b/CMakeLists.txt @@ -653,6 +653,7 @@ set(COMMON src/common/logging/backend.cpp src/common/arch.h src/common/assert.cpp src/common/assert.h + src/common/bit_array.h src/common/bit_field.h src/common/bounded_threadsafe_queue.h src/common/concepts.h diff --git a/src/common/bit_array.h b/src/common/bit_array.h new file mode 100644 index 000000000..870a5d1f5 --- /dev/null +++ b/src/common/bit_array.h @@ -0,0 +1,184 @@ +// SPDX-FileCopyrightText: Copyright 2024 shadPS4 Emulator Project +// SPDX-License-Identifier: GPL-2.0-or-later + +#pragma once + +#include +#include +#include "common/types.h" + +#ifdef __AVX2__ +#define BIT_ARRAY_USE_AVX +#include +#endif + +namespace Common { + +template +class BitArray { + static_assert(N % 64 == 0, "BitArray size must be a multiple of 64 bits."); + + static constexpr size_t BITS_PER_WORD = 64; + static constexpr size_t WORD_COUNT = N / BITS_PER_WORD; + static constexpr size_t WORDS_PER_AVX = 4; + static constexpr size_t AVX_WORD_COUNT = WORD_COUNT / WORDS_PER_AVX; + +public: + using Range = std::pair; + + inline constexpr void Set(size_t idx) { + data[idx / BITS_PER_WORD] |= (1ULL << (idx % BITS_PER_WORD)); + } + + inline constexpr void Unset(size_t idx) { + data[idx / BITS_PER_WORD] &= ~(1ULL << (idx % BITS_PER_WORD)); + } + + inline constexpr bool Get(size_t idx) const { + return (data[idx / BITS_PER_WORD] & (1ULL << (idx % BITS_PER_WORD))) != 0; + } + + inline constexpr void SetRange(size_t start, size_t end) { + if (start >= end || end > N) { + return; + } + const size_t first_word = start / BITS_PER_WORD; + const size_t last_word = (end - 1) / BITS_PER_WORD; + const size_t start_bit = start % BITS_PER_WORD; + const size_t end_bit = (end - 1) % BITS_PER_WORD; + const u64 start_mask = ~((1ULL << start_bit) - 1); + const u64 end_mask = end_bit == BITS_PER_WORD - 1 ? ~0ULL : (1ULL << (end_bit + 1)) - 1; + if (first_word == last_word) { + data[first_word] |= start_mask & end_mask; + } else { + data[first_word] |= start_mask; + size_t i = first_word + 1; +#ifdef BIT_ARRAY_USE_AVX + const __m256i value = _mm256_set1_epi64x(~1); + for (; i + WORDS_PER_AVX <= last_word; i += WORDS_PER_AVX) { + _mm256_storeu_si256(reinterpret_cast<__m256i*>(&data[i]), value); + } +#endif + for (; i < last_word; ++i) { + data[i] = ~0ULL; + } + data[last_word] |= end_mask; + } + } + + inline constexpr void UnsetRange(size_t start, size_t end) { + if (start >= end || end > N) { + return; + } + size_t first_word = start / BITS_PER_WORD; + const size_t last_word = (end - 1) / BITS_PER_WORD; + const size_t start_bit = start % BITS_PER_WORD; + const size_t end_bit = (end - 1) % BITS_PER_WORD; + const u64 start_mask = (1ULL << start_bit) - 1; + const u64 end_mask = end_bit == BITS_PER_WORD - 1 ? 0ULL : ~((1ULL << (end_bit + 1)) - 1); + if (first_word == last_word) { + data[first_word] &= start_mask | end_mask; + } else { + data[first_word] &= start_mask; + size_t i = first_word + 1; +#ifdef BIT_ARRAY_USE_AVX + const __m256i value = _mm256_setzero_si256(); + for (; i + WORDS_PER_AVX <= last_word; i += WORDS_PER_AVX) { + _mm256_storeu_si256(reinterpret_cast<__m256i*>(&data[i]), value); + } +#endif + for (; i < last_word; ++i) { + data[i] = 0ULL; + } + data[last_word] &= end_mask; + } + } + + inline constexpr void SetRange(const Range& range) { + SetRange(range.first, range.second); + } + + inline constexpr void UnsetRange(const Range& range) { + UnsetRange(range.first, range.second); + } + + inline constexpr void Clear() { + data.fill(0); + } + + inline constexpr bool None() const { + u64 result = 0; + for (const auto& word : data) { + result |= word; + } + return result == 0; + } + + inline constexpr bool Any() const { + return !None(); + } + + inline constexpr Range FirstSetFrom(size_t start) const { + if (start >= N) { + return {N, N}; + } + const auto find_end_bit = [&](size_t word) { +#ifdef BIT_ARRAY_USE_AVX + const __m256i all_one = _mm256_set1_epi64x(-1); + for (; word + WORDS_PER_AVX <= WORD_COUNT; word += WORDS_PER_AVX) { + const __m256i current = + _mm256_loadu_si256(reinterpret_cast(&data[word])); + const __m256i cmp = _mm256_cmpeq_epi64(current, all_one); + if (_mm256_movemask_epi8(cmp) != 0xFFFFFFFF) { + break; + } + } +#endif + for (; word < WORD_COUNT; ++word) { + if (data[word] != ~0ULL) { + return (word * BITS_PER_WORD) + std::countr_one(data[word]); + } + } + return N; + }; + + const auto word_bits = [&](size_t index, u64 word) { + const int empty_bits = std::countr_zero(word); + const int ones_count = std::countr_one(word >> empty_bits); + const size_t start_bit = index * BITS_PER_WORD + empty_bits; + if (ones_count + empty_bits < BITS_PER_WORD) { + return Range{start_bit, start_bit + ones_count}; + } + return Range{start_bit, find_end_bit(index + 1)}; + }; + + const size_t start_word = start / BITS_PER_WORD; + const size_t start_bit = start % BITS_PER_WORD; + const u64 masked_first = data[start_word] & (~((1ULL << start_bit) - 1)); + if (masked_first) { + return word_bits(start_word, masked_first); + } + + size_t word = start_word + 1; +#ifdef BIT_ARRAY_USE_AVX + for (; word + WORDS_PER_AVX <= WORD_COUNT; word += WORDS_PER_AVX) { + const __m256i current = + _mm256_loadu_si256(reinterpret_cast(&data[word])); + if (!_mm256_testz_si256(current, current)) { + break; + } + } +#endif + for (; word < WORD_COUNT; ++word) { + if (data[word] != 0) { + return word_bits(word, data[word]); + } + } + return {N, N}; + } + +private: + std::array data{}; +}; + +} // namespace Common \ No newline at end of file