CODE CMP
    HL  POPqq,
    DE  POPqq,
    chkPS,
    DE SUBHLss,
    BC 0 LDddnn,
    IFNZ, ( < or > )
        BC INCss,
        IFNC, ( < )
            BC DECss,
            BC DECss,
        THEN,
    THEN,
    BC PUSHqq,
;CODE

