56 lines
1.7 KiB
C
56 lines
1.7 KiB
C
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/* 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 <climits>
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#include "common/common_types.h"
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namespace Dynarmic {
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namespace 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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/// 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 T 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;
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}
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/// Sign-extends a value that has NBits 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 T signbit = Bit<bit_count - 1>(value);
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if (signbit != 0) {
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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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} // namespace Common
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} // namespace Dynarmic
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