CODE CMP
    HL  POP,
    DE  POP,
    chkPS,
    DE SUBHLd,
    BC 0 LDdn,
    IFNZ, ( < or > )
        BC INCd,
        IFNC, ( < )
            BC DECd,
            BC DECd,
        THEN,
    THEN,
    BC PUSH,
;CODE