d21659152c
Implement shifiting operations that perform consistently across architectures without running into undefined or implemented-defined behaviour.
109 lines
3.1 KiB
C++
109 lines
3.1 KiB
C++
/* This file is part of the dynarmic project.
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* Copyright (c) 2018 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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#include <type_traits>
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#include "common/bit_util.h"
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#include "common/common_types.h"
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#include "common/u128.h"
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namespace Dynarmic::Safe {
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template<typename T> T LogicalShiftLeft(T value, int shift_amount);
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template<typename T> T LogicalShiftRight(T value, int shift_amount);
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template<typename T> T ArithmeticShiftLeft(T value, int shift_amount);
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template<typename T> T ArithmeticShiftRight(T value, int shift_amount);
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template<typename T>
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T LogicalShiftLeft(T value, int shift_amount) {
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static_assert(std::is_integral_v<T>);
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if (shift_amount >= static_cast<int>(Common::BitSize<T>())) {
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return 0;
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}
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if (shift_amount < 0) {
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return LogicalShiftRight(value, -shift_amount);
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}
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auto unsigned_value = static_cast<std::make_unsigned_t<T>>(value);
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return static_cast<T>(unsigned_value << shift_amount);
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}
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template<>
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inline u128 LogicalShiftLeft(u128 value, int shift_amount) {
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return value << shift_amount;
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}
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template<typename T>
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T LogicalShiftRight(T value, int shift_amount) {
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static_assert(std::is_integral_v<T>);
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if (shift_amount >= static_cast<int>(Common::BitSize<T>())) {
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return 0;
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}
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if (shift_amount < 0) {
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return LogicalShiftLeft(value, -shift_amount);
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}
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auto unsigned_value = static_cast<std::make_unsigned_t<T>>(value);
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return static_cast<T>(unsigned_value >> shift_amount);
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}
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template<>
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inline u128 LogicalShiftRight(u128 value, int shift_amount) {
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return value >> shift_amount;
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}
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template<typename T>
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T LogicalShiftRightDouble(T top, T bottom, int shift_amount) {
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return LogicalShiftLeft(top, int(Common::BitSize<T>()) - shift_amount) | LogicalShiftRight(bottom, shift_amount);
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}
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template<typename T>
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T ArithmeticShiftLeft(T value, int shift_amount) {
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static_assert(std::is_integral_v<T>);
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if (shift_amount >= static_cast<int>(Common::BitSize<T>())) {
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return 0;
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}
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if (shift_amount < 0) {
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return ArithmeticShiftRight(value, -shift_amount);
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}
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auto signed_value = static_cast<std::make_signed_t<T>>(value);
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return static_cast<T>(signed_value << shift_amount);
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}
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template<typename T>
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T ArithmeticShiftRight(T value, int shift_amount) {
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static_assert(std::is_integral_v<T>);
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if (shift_amount >= static_cast<int>(Common::BitSize<T>())) {
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return Common::MostSignificantBit(value) ? ~static_cast<T>(0) : 0;
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}
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if (shift_amount < 0) {
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return ArithmeticShiftLeft(value, -shift_amount);
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}
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auto signed_value = static_cast<std::make_signed_t<T>>(value);
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return static_cast<T>(signed_value >> shift_amount);
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}
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template<typename T>
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T ArithmeticShiftRightDouble(T top, T bottom, int shift_amount) {
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return ArithmeticShiftLeft(top, int(Common::BitSize<T>()) - shift_amount) | LogicalShiftRight(bottom, shift_amount);
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}
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template<typename T>
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T Negate(T value) {
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return static_cast<T>(-static_cast<std::make_signed_t<T>>(value));
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}
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} // namespace Dynarmic::Safe
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