137 lines
4 KiB
C++
137 lines
4 KiB
C++
/* This file is part of the dynarmic project.
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* Copyright (c) 2016 MerryMage
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* This software may be used and distributed according to the terms of the GNU
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* General Public License version 2 or any later version.
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*/
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#pragma once
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#include <bitset>
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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/assert.h"
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namespace Dynarmic::Common {
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/// The size of a type in terms of bits
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template<typename T>
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constexpr size_t BitSize() {
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return sizeof(T) * CHAR_BIT;
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}
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/// Extract bits [begin_bit, end_bit] inclusive from value of type T.
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template<size_t begin_bit, size_t end_bit, typename T>
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constexpr T Bits(const T value) {
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static_assert(begin_bit <= end_bit,
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"invalid bit range (position of beginning bit cannot be greater than that of end bit)");
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static_assert(begin_bit < BitSize<T>(), "begin_bit must be smaller than size of T");
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static_assert(end_bit < BitSize<T>(), "begin_bit must be smaller than size of T");
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return (value >> begin_bit) & ((1 << (end_bit - begin_bit + 1)) - 1);
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}
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#ifdef _MSC_VER
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#pragma warning(push)
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#pragma warning(disable:4554)
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#endif
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/// Extracts a single bit at bit_position from value of type T.
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template<size_t bit_position, typename T>
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constexpr bool Bit(const T value) {
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static_assert(bit_position < BitSize<T>(), "bit_position must be smaller than size of T");
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return ((value >> bit_position) & 1) != 0;
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}
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/// Extracts a single bit at bit_position from value of type T.
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template<typename T>
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inline bool Bit(size_t bit_position, const T value) {
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ASSERT_MSG(bit_position < BitSize<T>(), "bit_position must be smaller than size of T");
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return ((value >> bit_position) & 1) != 0;
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}
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#ifdef _MSC_VER
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#pragma warning(pop)
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#endif
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/// Sign-extends a value that has bit_count bits to the full bitwidth of type T.
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template<size_t bit_count, typename T>
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inline T SignExtend(const T value) {
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static_assert(bit_count <= BitSize<T>(), "bit_count larger than bitsize of T");
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constexpr T mask = static_cast<T>(1ULL << bit_count) - 1;
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const bool signbit = Bit<bit_count - 1, T>(value);
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if (signbit) {
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return value | ~mask;
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}
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return value;
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}
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/// Sign-extends a value that has bit_count bits to the full bitwidth of type T.
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template<typename T>
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inline T SignExtend(const size_t bit_count, const T value) {
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ASSERT_MSG(bit_count <= BitSize<T>(), "bit_count larger than bitsize of T");
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const T mask = static_cast<T>(1ULL << bit_count) - 1;
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const bool signbit = Bit<T>(bit_count - 1, value);
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if (signbit) {
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return value | ~mask;
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}
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return value;
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}
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template <typename Integral>
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inline size_t BitCount(Integral value) {
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return std::bitset<BitSize<Integral>()>(value).count();
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}
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template <typename T>
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inline int HighestSetBit(T value) {
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auto x = static_cast<std::make_unsigned_t<T>>(value);
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int result = -1;
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while (x != 0) {
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x >>= 1;
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result++;
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}
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return result;
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}
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template <typename T>
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inline size_t LowestSetBit(T value) {
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auto x = static_cast<std::make_unsigned_t<T>>(value);
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if (x == 0)
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return BitSize<T>();
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size_t result = 0;
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while ((x & 1) == 0) {
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x >>= 1;
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result++;
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}
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return result;
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}
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template <typename T>
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inline T Ones(size_t count) {
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ASSERT_MSG(count <= BitSize<T>(), "count larger than bitsize of T");
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if (count == BitSize<T>())
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return ~static_cast<T>(0);
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return ~(~static_cast<T>(0) << count);
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}
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template <typename T>
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inline T Replicate(T value, size_t element_size) {
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ASSERT_MSG(BitSize<T>() % element_size == 0, "bitsize of T not divisible by element_size");
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if (element_size == BitSize<T>())
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return value;
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return Replicate(value | (value << element_size), element_size * 2);
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}
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template <typename T>
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inline T RotateRight(T value, size_t amount) {
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amount %= BitSize<T>();
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auto x = static_cast<std::make_unsigned_t<T>>(value);
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return static_cast<T>((x >> amount) | (x << (BitSize<T>() - amount)));
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}
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} // namespace Dynarmic::Common
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