mirror of
https://github.com/azahar-emu/dynarmic
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58 lines
1.8 KiB
C++
58 lines
1.8 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 "common/fp/fpcr.h"
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#include "common/fp/fpsr.h"
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#include "common/fp/fused.h"
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#include "common/fp/info.h"
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#include "common/fp/op/FPNeg.h"
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#include "common/fp/op/FPRSqrtStepFused.h"
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#include "common/fp/process_exception.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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template<typename FPT>
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FPT FPRSqrtStepFused(FPT op1, FPT op2, FPCR fpcr, FPSR& fpsr) {
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op1 = FPNeg(op1);
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const auto [type1, sign1, value1] = FPUnpack<FPT>(op1, fpcr, fpsr);
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const auto [type2, sign2, value2] = FPUnpack<FPT>(op2, fpcr, fpsr);
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if (const auto maybe_nan = FPProcessNaNs(type1, type2, op1, op2, fpcr, fpsr)) {
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return *maybe_nan;
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}
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const bool inf1 = type1 == FPType::Infinity;
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const bool inf2 = type2 == FPType::Infinity;
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const bool zero1 = type1 == FPType::Zero;
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const bool zero2 = type2 == FPType::Zero;
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if ((inf1 && zero2) || (zero1 && inf2)) {
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// return +1.5
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return FPValue<FPT, false, -1, 3>();
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}
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if (inf1 || inf2) {
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return FPInfo<FPT>::Infinity(sign1 != sign2);
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}
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// result_value = (3.0 + (value1 * value2)) / 2.0
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FPUnpacked result_value = FusedMulAdd(ToNormalized(false, 0, 3), value1, value2);
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result_value.exponent--;
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if (result_value.mantissa == 0) {
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return FPInfo<FPT>::Zero(fpcr.RMode() == RoundingMode::TowardsMinusInfinity);
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}
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return FPRound<FPT>(result_value, fpcr, fpsr);
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}
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template u32 FPRSqrtStepFused<u32>(u32 op1, u32 op2, FPCR fpcr, FPSR& fpsr);
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template u64 FPRSqrtStepFused<u64>(u64 op1, u64 op2, FPCR fpcr, FPSR& fpsr);
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} // namespace Dynarmic::FP
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