DUART   EQU $00C001
IPR EQU $1A
OPR_SET EQU $1C
OPR_CLR EQU $1E
SRA EQU 2
RBA EQU 6

    ORG $8000
WIRE681 MOVEA.L #DUART,A0

LOOP    MOVE.B  SRA(A0),D7
    ANDI.B  #1,D7
    BEQ LOOP

    MOVE.B  RBA(A0),D0
    CMP.B   #113,D0
    BEQ EXIT
    BSR OUT681
    BRA LOOP

OUT681  MOVE.B  D0,OPR_CLR(A0)
    NOT.B   D0
    MOVE.B  D0,OPR_SET(A0)
    RTS
EXIT    TRAP    #14
    END WIRE681