FUNCTIONAL SYNTHESIS OF DIGITAL-SYSTEMS WITH TASS

Synthesizing a digital system from a functional description is a compl ex process requiring the solution of various different problems. TASS (Tabu Search Synthesis System) is a functional synthesis system made u p of interdependent modules based on new and more efficient algorithms . First, a control and data flow graph model for system representation is developed and presented. This model generates a single graph repre senting both the data and control flows of a VHDL behavioral descripti on. A new representation of conditional branches and a mutual exclusio n testing procedure offering optimized resource sharing and critical p ath reduction possibilities have been developed. This graph model is a n environment used for various synthesis needs starting from high-leve l transformations to FSM synthesis for controller implementation. A ne w mathematical formulation of the scheduling problem is developed usin g a new approach based on penalty weights. This approach avoids the in flexibility of the ILP formulations developed in related works where t he functional unit performing each type of operation is fixed prior to scheduling. The Tabu Search technique, which has been effective in fi nding optimal solutions for many types of large and difficult combinat orial optimization problems, has been adapted for this purpose. This t echnique, which performs an intelligent and fast solution space explor ation, combined with an effective mathematical formulation makes the s cheduling algorithm presented here very powerful.