public static void XchgAWReg(int Reg) {
        /*WORD*/
        int tmp;
        tmp = I.regs.w[Reg];
        I.regs.SetW(Reg, I.regs.w[AW]);
        I.regs.SetW(AW, tmp & 0xFFFF);
        nec_ICount[0] -= 3;
    }