Sequential logic synthesis using symbolic bi-decomposition

This paper uses under-approximation of unreachable states of a design to derive incomplete specification of combinational logic. The resulting incompletely-specified functions are decomposed to enhance the quality of technology-dependent synthesis. The decomposition choices are computed implicitly using novel formulation of symbolic bi-decomposition that is applied recursively to decompose logic in terms of simple primitives. The ability of BDDs to represent compactly certain exponentially large combinatorial sets helps us to implicitly enumerate and explore variety of decomposition choices improving quality of synthesized circuits. Benefits of the symbolic technique are demonstrated in sequential synthesis of publicly available benchmarks as well as on the realistic industrial designs.