  Extended addressing machines (EAMs) have been introduced to represent
higher-order sequential computations. Previously, we have shown that they are
capable of simulating -- via an easy encoding -- the operational semantics of
PCF, extended with explicit substitutions. In this paper we prove that the
simulation is actually an equivalence: a PCF program terminates in a numeral
exactly when the corresponding EAM terminates in the same numeral. It follows
that the model of PCF obtained by quotienting typable EAMs by a suitable
logical relation is adequate. From a definability result stating that every EAM
in the model can be transformed into a PCF program with the same observational
behavior, we conclude that the model is fully abstract for PCF.
