Transformational partitioning for codesign

This paper presents the underlying methodology of Cosmos: an interactive approach for hardware/software codesign capable of handling multiprocessor systems and distributed architectures. The approach covers the codesign process through a set of user guided transformations allowing semiautomatic partitioning. The transformations are based on a powerful set of primitives for functional partitioning, structural reorganisation and communication transformation. It leads to a fast transformation of a system-level specification into an architecture with a short design time and easy exploration of design space. The application of this approach is illustrated using two design examples starting from a system-level specification given in SDL to a distributed hardware/software architecture described in C/VHDL. We show that the use of transformational approach allows: (i) application of the expertise of the designer during partitioning; (ii) the user to understand the results of the codesign process; (iii) the process to take into account partial existing solutions; (iv) easy design space exploration; (v) the designer to start from a very high-level specification language of the system to be designed