t at ln 24        
:
  txa
  pha           ; save X
  jsr erase_line_by_number      ; erase line
  pla
  tax           ; restore X
  dex           ; previous line
  bpl :-
  jmp @end_escape_seq


; --- r ---  set scroll region                 
@not_J:
  cmp #$72    ; r?
  bne @not_r
  ; -- prepare top --
  jsr get_number_from_esc_seq
  cmp #$3b    ; is ;?
  bne @error_in_escape_seq   ; no -> error
  ldy escape_parameter    ; get top
  dey         ; line 1 -> line 0
  cpy #$19    ; >=25