.TITLE  REVERS
        .MCALL  .GTLIN,.PRINT,.EXIT
REVERS::.GTLIN  #1$             ; READ STRING
        MOV     #1$,R0
        JSR     PC,REV          ; REVERSE IT
        .PRINT  #1$             ; PRINT RESULT
        .EXIT
1$:     .BLKB   200

        ; REVERSE STRING AT R0
REV:    MOV     R0,R1
1$:     TSTB    (R1)+           ; FIND END OF STRING
        BNE     1$
        DEC     R1              ; MOVE BACK TO LAST CHAR
2$:     MOVB    -(R1),R2        ; SWAP CHARS
        MOVB    (R0),(R1)
        MOVB    R2,(R0)+
        CMP     R0,R1           ; STOP WHEN POINTERS MEET
        BLT     2$
        RTS     PC

        .END    REVERS