  We show that a 3-port interferometer, defined by quantum point contacts in a
two-dimensional electron gas, and working in the quantum Hall regime, can
implement different logic gates at each port depending on the energy of charge
carriers and the operating conditions. In all cases the input logic states are
encoded in the potentials applied on the quantum point contacts, while the
output logic states are encoded in the values of the overall transmission
coefficients at each port. In addition, the output of such compact
configurations can be reprogrammed by combining two 3-port interferometers.
