MAIN    START
        OUT     STRT,L1
LOOP    IN      IOBUF,IOLEN
        LD      GR1,IOLEN
        JZE     FIN
        OUT     TYPD,L2
        OUT     IOBUF,IOLEN
        OUT     WHTNXT,L3
        JUMP    LOOP
FIN     RET
;;; メッセージと長さ
STRT    DC      'LET''S START. TYPE IN'
L1      DC      20
TYPD    DC      'YOU TYPED'
L2      DC      9
WHTNXT  DC      'WHAT''S NEXT?'
L3      DC      12
;;; 入出力領域
IOBUF   DS      64
IOLEN   DS      1
        END