anchor.diff:  : fb8-background inverse? ;
   : fb8-foreground inverse? invert ;
   
  -: fb8-lines2bytes ( #lines -- #bytes ) char-height * screen-width * screen-depth * ;
  +: fb8-lines2bytes ( #lines -- #bytes ) char-height * screen-line-bytes * ;
   : fb8-columns2bytes ( #columns -- #bytes ) char-width * screen-depth * ;
   : fb8-line2addr ( line# -- addr )
  -	char-height * window-top + screen-width * screen-depth *
  +	char-height * window-top + screen-line-bytes *
   	frame-buffer-adr + window-left screen-depth * +
   ;
   
  
positive.code: 
  : fb8-toggle-cursor ( -- )
  	line# fb8-line2addr column# fb8-columns2bytes +
  	char-height 2 - screen-width screen-depth * * +
  	2 0 ?DO
  		dup char-width screen-depth * invert-region
  		screen-width screen-depth * +
  	LOOP drop
  ;
  
  
negative.code: 	>r
  	fb8-install
  	r> to screen-depth
  	screen-width screen-depth * to screen-line-bytes
  ;
  
  
  