Modal processes: towards enhanced retargetability through control composition of distributed embedded systems

To explore different points in the design space of an embedded system, it is important to be able to compose a design from reusable design components, and then map the resulting system description onto several possible target architectures with different partitionings of functionality. Today's specification models support composition styles that work well for data communication but not for control communication between concurrent processes to be mapped onto a distributed architecture. We propose a new retargetable system specification model that combines the best properties of process-based and hierarchical-FSM-based methods for modular composition of data and control. The model lends itself to automated synthesis of the run-time system for coordinating tasks on different processors in the system. The model and synthesis method are illustrated with several examples of embedded systems.