dynarmic/src/frontend/translate/translate_arm/reversal.cpp

/* This file is part of the dynarmic project.
 * Copyright (c) 2016 MerryMage
 * This software may be used and distributed according to the terms of the GNU
 * General Public License version 2 or any later version.
 */

#include "translate_arm.h"

namespace Dynarmic {
namespace Arm {

bool ArmTranslatorVisitor::arm_REV(Cond cond, Reg d, Reg m) {
    // REV<c> <Rd>, <Rm>
    if (d == Reg::PC || m == Reg::PC)
        return UnpredictableInstruction();

    if (ConditionPassed(cond)) {
        auto result = ir.ByteReverseWord(ir.GetRegister(m));
        ir.SetRegister(d, result);
    }
    return true;
}

bool ArmTranslatorVisitor::arm_REV16(Cond cond, Reg d, Reg m) {
    if (d == Reg::PC || m == Reg::PC)
        return UnpredictableInstruction();

    if (ConditionPassed(cond)) {
        auto reg_m = ir.GetRegister(m);
        auto lo = ir.And(ir.LogicalShiftRight(reg_m, ir.Imm8(8), ir.Imm1(0)).result, ir.Imm32(0x00FF00FF));
        auto hi = ir.And(ir.LogicalShiftLeft(reg_m, ir.Imm8(8), ir.Imm1(0)).result, ir.Imm32(0xFF00FF00));
        auto result = ir.Or(lo, hi);
        ir.SetRegister(d, result);
    }
    return true;
}

bool ArmTranslatorVisitor::arm_REVSH(Cond cond, Reg d, Reg m) {
    // REVSH<c> <Rd>, <Rm>
    if (d == Reg::PC || m == Reg::PC)
        return UnpredictableInstruction();

    if (ConditionPassed(cond)) {
        auto rev_half = ir.ByteReverseHalf(ir.LeastSignificantHalf(ir.GetRegister(m)));
        ir.SetRegister(d, ir.SignExtendHalfToWord(rev_half));
    }
    return true;
}

} // namespace Arm
} // namespace Dynarmic