67 lines
1.8 KiB
C++
67 lines
1.8 KiB
C++
// Copyright 2018 yuzu emulator team
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// Licensed under GPLv2 or any later version
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// Refer to the license.txt file included.
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#pragma once
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#include <bit>
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#include <climits>
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#include <cstddef>
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#include <type_traits>
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#include "common/common_types.h"
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namespace Common {
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/// Gets the size of a specified type T in bits.
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template <typename T>
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[[nodiscard]] constexpr std::size_t BitSize() {
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return sizeof(T) * CHAR_BIT;
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}
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[[nodiscard]] constexpr u32 MostSignificantBit32(const u32 value) {
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return 31U - static_cast<u32>(std::countl_zero(value));
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}
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[[nodiscard]] constexpr u32 MostSignificantBit64(const u64 value) {
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return 63U - static_cast<u32>(std::countl_zero(value));
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}
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[[nodiscard]] constexpr u32 Log2Floor32(const u32 value) {
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return MostSignificantBit32(value);
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}
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[[nodiscard]] constexpr u32 Log2Floor64(const u64 value) {
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return MostSignificantBit64(value);
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}
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[[nodiscard]] constexpr u32 Log2Ceil32(const u32 value) {
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const u32 log2_f = Log2Floor32(value);
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return log2_f + static_cast<u32>((value ^ (1U << log2_f)) != 0U);
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}
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[[nodiscard]] constexpr u32 Log2Ceil64(const u64 value) {
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const u64 log2_f = Log2Floor64(value);
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return static_cast<u32>(log2_f + static_cast<u64>((value ^ (1ULL << log2_f)) != 0ULL));
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}
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template <typename T>
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requires std::is_unsigned_v<T>
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[[nodiscard]] constexpr bool IsPow2(T value) {
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return std::has_single_bit(value);
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}
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template <typename T>
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requires std::is_integral_v<T>
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[[nodiscard]] T NextPow2(T value) {
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return static_cast<T>(1ULL << ((8U * sizeof(T)) - std::countl_zero(value - 1U)));
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}
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template <size_t bit_index, typename T>
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requires std::is_integral_v<T>
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[[nodiscard]] constexpr bool Bit(const T value) {
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static_assert(bit_index < BitSize<T>(), "bit_index must be smaller than size of T");
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return ((value >> bit_index) & T(1)) == T(1);
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}
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} // namespace Common
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