Compiling Modechart Specifications

The Modechart specification language is a formalism for the specification of real-time systems. A toolset for specification, analysis and simulation for Modechart specifications exists for supporting the design and construction of real-time systems [CHLR93]. This paper introduces a new tool in the the toolset: a compiler for a class of Modechart specifications, namely, that of deterministic system specifications, extended by a subclass of the non-deterministic system specifications. The object code that the compiler generates is in ESTEREL, a member of the synchronous family of programming languages for real-time systems. We discuss a broad approach to the implementation of timing specifications, providing a range of implementation options, from the basic time step unrollingof states in ESTEREL, to the use of system timers. The compiler presented herein allows the specifier to obtain a correct implementationof a modechart program, including timing constraints.