A fixed point theorem is
proved for inverse transducers, which leads to an automata-theoretic proof of the
fixed point subgroup of an endomorphism of a finitely generated virtually free group
being finitely generated. If the endomorphism is uniformly continuous for
the hyperbolic metric, it is proved that the set of regular fixed points in
the hyperbolic boundary has finitely many orbits under the action of the
finite fixed points. In the automorphism case, it is shown that these regular
fixed points are either exponentially stable attractors or exponentially stable
repellers.