Operational Semantics of a Data Flow Language

Abstract

A data flow machine achieves high performance by the concurrent execution of machine code consisting of data flow graphs which explicitly represent the data dependencies among program instructions. This thesis presents the operational semantics of ADFL, an applicative data flow language with an iteration construct resembling tail recursion and an error-handling scheme appropriate to the concurrency of data flow. The operation semantics O*T of ADFL are expressed by a two step process. The translation algorithm T maps an ADFL expression into its graph implementation, and the semantic function O maps the graph into its semantic characterization. Data flow graphs are specified by use of a graph assembly language, and the semantics of these graphs are derived by use of Kahn's fixpoint theory of communciating processes.