: _clrrows ( n u -- Clears u rows starting at n )
    SWAP _row!
    ( u ) 0 DO
        _yinc 0 _col!
        11 0 DO 0 _data! LOOP
        _xinc 0 _data!
    LOOP ;
: NEWLN ( ln -- )
    DUP 1+ FNTH 1+ * _zoff!
    FNTH 1+ * FNTH 1+ _clrrows ;
: LCDCLR 0 64 _clrrows ;