Compositionality in Dataflow Synchronous Languages: Specification and Distributed Code Generation

Abstract

This paper is a signi cantly revised version of a preliminary report which appeared under the same title in the Proceedings of 1997 Malente Workshop on Compositionality, organized by W.P. de Roever and H. Langmaack; these proceedings will be published in the LNCS, Springer Verlag. y This work is or has been supported in part by the following projects : Eureka-SYNCHRON, Esprit R&D-SACRES (Esprit project EP 20897), Esprit LTR-SYRF (Esprit project EP 22703). z In addition to the listed authors, the following people have indirectly, but strongly, contributed to this work : the sts formalism has been shamelessly borrowed from Amir Pnueli, the background on labelled partial orders is mostly ackowledged to Paul Caspi.

Distributing synchronous systems with modular structure

“…we need a trace map χ :T RA →T ST S * where T RA and T ST S are the set of traces of STS and RA respectively. In [10] the following definition of an invertible map χ is given:…”

“…It has been proved in [10] that for the set of endochronous programs such a φ exists. In section V we define a φ for the class of STS*.…”

“…[2]. We can now formulate our problem (like [10]) as follows: we seek a composition operator × RA such that, for any two STS* s 1 and s 2 and RA r 1 and r 2 , the following holds:…”

“…This is now an active field of research. [8]- [9] propose algorithms to distribute particular subsets of ESTEREL programs, starting with a single synchronous program and splitting it into synchronous subsystems intercommunicating through an asynchronous medium creating what is called a Globally Asynchronous Locally Synchronous (GALS) system [10]. This approach preserves the synchronous semantics but does not maintain or exploit the modular structure in the original synchronous program.…”

“…The asynchronous composition operator is CSP-style rendezvous [12]. We present an algorithm to implement a synchronous program into an asynchronous one and prove the implementation map preserves the synchronous semantics in the sense of [10]. The main result is that the implementation is a monomorphism with respect to the synchronous and asynchronous compositions.…”