Grounding Synchronous Deterministic Concurrency in Sequential Programming

Using a new domain-theoretic characterisation we show that Berry's constructive semantics is a conservative approximation of the recently proposed sequentially constructive SC model of computation. We prove that every Berry-constructive program is deterministic and deadlock-free under sequentially admissible scheduling. This gives, for the first time, a natural interpretation of Berry-constructiveness for shared-memory, multi-threaded programming in terms of synchronous cycle-based scheduling, where previous results were cast in terms of synchronous circuits. This opens the door to a direct mapping of Esterel's signal mechanism into boolean variables that can be set and reset under the programmer's control within a tick. We illustrate the practical usefulness of this mapping by discussing how signal reincarnation is handled efficiently by this transformation, which is of linear complexity in program size, in contrast to earlier techniques that had quadratic overhead.