CODE PC! EXX, ( protect BC )
    BC POP,
    HL POP,
    L OUT(C)r,
EXX, ( unprotect BC ) ;CODE

CODE PC@ EXX, ( protect BC )
    BC POP,
    chkPS,
    H 0 LDri,
    L INr(C),
    HL PUSH,
EXX, ( unprotect BC ) ;CODE