Retiming and resynthesis: optimizing sequential networks with combinational techniques

Sequential networks contain combinational logic blocks separated by registers. Application of combinational logic minimization techniques to the separate logic blocks results in improvement that is restricted by the placement of the registers; information about logical dependencies between blocks separated by registers is not utilized. Temporarily moving all the registers to the periphery of a network provides the combinational logic minimization tools with a global view of the logic. We propose a technique for optimizing a sequential network by moving the registers to the boundary of the network using an extension of retiming [SI, 191, resynthesizing the combinational logic between the registers using existing logic minimization techniques, and replacing the registers throughout the network using retiming algorithms.