Interface Synthesis in Heterogeneous System-Level DSP Design Tools

Using incremental compilation, a compute-intensive subsystem in, for example, the SDF simulation domain can be retargeted to CGC (code generation in C) and compiled to become a single monolithic actor in SDF (figure 1). A similar capability is used to encapsulate a CG56 subsystem (which runs on the Motorola DSP56000) into an SDF actor. This new actor can then be added to the designer's actor library.

The interface mechanism also allows for easy incorporation of foreign simulators. For example, a VHDL subsystem can be analyzed to synthesize a fast customized C interface to a commercial VHDL simulator. The VHDL subsystem in turn can be interfaced with another system that executes on a DSP card.

Finally, the framework allows the combination of more than one code generation domain. For example, CGC can be mixed with CG56 to produce programs that execute concurrently on a host workstation and a DSP card.

A fundamental problem is that dataflow systems cannot always be incrementally compiled. The problem lies in the fact that dataflow systems lack the composition property. Thus subsystems of dataflow actors in an application specification do not necessarily have the same semantics as an individual actor.

1. J. L. Pino, M. C. Williamson, and E. A. Lee, ``Interface Synthesis in Heterogeneous System-Level DSP Design Tools,'' submitted to Proc. IEEE Int. Conf. on Acoustics, Speech, and Signal Processing, Atlanta, GA, May 1996.