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c9777ef997
While initially done to potentially prevent creating bugs due to C++ having a silly type-promotion mechanism involving types < sizeof(int) and unsignedness, given that the bulk of these functions' usages are on exit paths, these can return the correct type to avoid the need to cast at every usage point.
61 lines
2.0 KiB
C++
61 lines
2.0 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 <tuple>
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#include "common/common_types.h"
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#include "common/bit_util.h"
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#include "common/fp/fpcr.h"
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#include "common/fp/fpsr.h"
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#include "common/fp/info.h"
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#include "common/fp/op/FPRecipExponent.h"
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#include "common/fp/process_nan.h"
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#include "common/fp/unpacked.h"
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namespace Dynarmic::FP {
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namespace {
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template <typename FPT>
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FPT DetermineExponentValue(size_t value) {
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if constexpr (sizeof(FPT) == sizeof(u32)) {
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return static_cast<FPT>(Common::Bits<23, 30>(value));
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} else if constexpr (sizeof(FPT) == sizeof(u64)) {
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return static_cast<FPT>(Common::Bits<52, 62>(value));
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} else {
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return static_cast<FPT>(Common::Bits<10, 14>(value));
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}
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}
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} // Anonymous namespace
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template <typename FPT>
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FPT FPRecipExponent(FPT op, FPCR fpcr, FPSR& fpsr) {
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const auto [type, sign, value] = FPUnpack<FPT>(op, fpcr, fpsr);
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(void)value;
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if (type == FPType::SNaN || type == FPType::QNaN) {
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return FPProcessNaN(type, op, fpcr, fpsr);
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}
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const FPT sign_bits = FPInfo<FPT>::Zero(sign);
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const FPT exponent = DetermineExponentValue<FPT>(op);
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// Zero and denormals
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if (exponent == 0) {
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const FPT max_exponent = Common::Ones<FPT>(FPInfo<FPT>::exponent_width) - 1;
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return FPT(sign_bits | (max_exponent << FPInfo<FPT>::explicit_mantissa_width));
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}
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// Infinities and normals
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const FPT negated_exponent = FPT(~exponent);
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const FPT adjusted_exponent = FPT(negated_exponent << FPInfo<FPT>::explicit_mantissa_width) & FPInfo<FPT>::exponent_mask;
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return FPT(sign_bits | adjusted_exponent);
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}
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template u16 FPRecipExponent<u16>(u16 op, FPCR fpcr, FPSR& fpsr);
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template u32 FPRecipExponent<u32>(u32 op, FPCR fpcr, FPSR& fpsr);
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template u64 FPRecipExponent<u64>(u64 op, FPCR fpcr, FPSR& fpsr);
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} // namespace Dynarmic::FP
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