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Relocations: Disable 6-byte size optimization in InsertGuestRIPMove #5202

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Merged
Sonicadvance1 merged 1 commit into from
Jan 7, 2026
Merged

Relocations: Disable 6-byte size optimization in InsertGuestRIPMove #5202

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5 changes: 4 additions & 1 deletion FEXCore/Source/Interface/Core/JIT/Arm64Relocations.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -94,7 +94,10 @@ void Arm64JITCore::InsertGuestRIPMove(ARMEmitter::Register Reg, uint64_t Constan
MoveABI.GuestRIP.RegisterIndex = Reg.Idx();

// Pointers are required to fit within 48-bit VA space.
LoadConstant(ARMEmitter::Size::i64Bit, Reg, Constant, FEXCore::CPU::Arm64Emitter::PadType::AUTOPAD, 6);
// TODO: Force 6-byte `MaxSize`, with sign extension to 64-bit. Current code not smart enough to handle negatives.
// 48-bit sign extension works because x86-64 guests only receive 47-bit VA space, with 48-bit being reserved for kernel.
// Additional quirk, "canonical" 48-bit pointers on x86-64, sign extend the 48-bit as well (Which is why kernel pointers are negative).
LoadConstant(ARMEmitter::Size::i64Bit, Reg, Constant, FEXCore::CPU::Arm64Emitter::PadType::AUTOPAD);
Relocations.emplace_back(MoveABI);
}

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