An Implementation of Constructive Synchronous Programs in POLIS

Design tools for embedded reactive systems commonly use a model of computation that employs both synchronous and asynchronous communication styles. We form a junction between these two with an implementation of synchronous languages and circuits (Esterel) on asynchronous networks (POLIS). We implement fact propagation, the key concept of synchronous constructive semantics, on an asynchronous non-deterministic network: POLIS nodes (CFSMs) save state locally to deduce facts, and the network globally propagates facts between them. The result is a correct implementation of the synchronous input/output behavior of the program. Our model is compositional, and thus permits implementations at various levels of granularity from one CFSM per circuit gate to one CFSM per circuit. This allows one to explore various tradeoffs between synchronous and asynchronous implementations.

[1]  A. Sangiovanni-Vincentelli,et al.  Formal analysis of synchronous circuits , 1996 .

[2]  C. A. R. Hoare,et al.  Communicating sequential processes , 1978, CACM.

[3]  Luciano Lavagno,et al.  Formal verification of embedded systems based on CFSM networks , 1996, DAC '96.

[4]  David Harel,et al.  Statecharts: A Visual Formalism for Complex Systems , 1987, Sci. Comput. Program..

[5]  Thomas R. Shiple,et al.  Constructive analysis of cyclic circuits , 1996, Proceedings ED&TC European Design and Test Conference.

[6]  Luciano Lavagno,et al.  Hardware-software co-design of embedded systems: the POLIS approach , 1997 .

[7]  Pascal Raymond,et al.  The synchronous data flow programming language LUSTRE , 1991, Proc. IEEE.

[8]  Horia Alexandru Toma.  Analyse constructive et optimisation séquentielle des circuits générés à partir du langage synchrone réactif ESTEREL , 1997 .

[9]  Benoît Caillaud,et al.  Distributing Automata for Asynchronous Networks of Processors , 1997 .

[10]  Charles André.  Representation and Analysis of Reactive Behaviors: A Synchronous Approach , 2000 .

[11]  Gilles Kahn,et al.  The Semantics of a Simple Language for Parallel Programming , 1974, IFIP Congress.

[12]  Sharad Malik.  Analysis of cyclic combinational circuits , 1994, IEEE Trans. Comput. Aided Des. Integr. Circuits Syst..

[13]  Nicolas Halbwachs,et al.  Synchronous Programming of Reactive Systems , 1992, CAV.

[14]  Gérard Berry,et al.  The Esterel Synchronous Programming Language: Design, Semantics, Implementation , 1992, Sci. Comput. Program..

[15]  Roberto M. Amadio,et al.  Domains and lambda-calculi , 1998, Cambridge tracts in theoretical computer science.

[16]  Gérard Berry,et al.  The foundations of Esterel , 2000, Proof, Language, and Interaction.

[17]  P. Caspi,et al.  Distributing reactive systems , 1994 .

[18]  Thierry Gautier,et al.  Programming real-time applications with SIGNAL , 1991, Proc. IEEE.