NORMAL MODE IS INTEGER
            INTERNAL FUNCTION(AA, BB)
            ENTRY TO MULINV.
            A = AA
            B = BB
            WHENEVER B.L.0, B = -B
            WHENEVER A.L.0, A = B - (-(A-A/B*B))
            T = 0
            NT = 1
            R = B
            NR = A-A/B*B
LOOP        WHENEVER NR.NE.0
                Q = R/NR
                TMP = NT
                NT = T - Q*NT
                T = TMP
                TMP = NR
                NR = R - Q*NR
                R = TMP
                TRANSFER TO LOOP
            END OF CONDITIONAL
            WHENEVER R.G.1, FUNCTION RETURN -1
            WHENEVER T.L.0, T = T+B
            FUNCTION RETURN T
            END OF FUNCTION

            INTERNAL FUNCTION(AA, BB)
            VECTOR VALUES FMT = $I5,2H, ,I5,2H: ,I5*$
            ENTRY TO SHOW.
            PRINT FORMAT FMT, AA, BB, MULINV.(AA, BB)
            END OF FUNCTION

            SHOW.(42,2017)
            SHOW.(40,1)
            SHOW.(52,-217)
            SHOW.(-486,217)
            SHOW.(40,2018)
            END OF PROGRAM