." serial " 

voc: serial
serial
 : init vector ;

 $3F8 constant COM1
 $2F8 constant COM2
 $3E8 constant COM3
 $2E8 constant COM4
 COM2 variable: SERIAL-PORT
 : com# SERIAL-PORT @ ;
 : received? com# 5 + p1@ 1 and ;
 : empty? com# 5 + p1@ $20 and ;
 : read received? if com# p1@ ;then read ;
 : write empty?   if com# p1! ;then write ;
 : send for dup c@ write 1+ next drop ;

 loc:
   : a  $0 com# 1 + p1! $80 com# 3 + p1! ;
   : b $03 com# 0 + p1!  $0 com# 1 + p1! ;
   : c $03 com# 3 + p1! $C7 com# 2 + p1! ;
   : d $0B com# 4 + p1! ;
   here is init ] a b c d ;
 ;loc
^