Smart move: a placement-aware retiming and replication method for field programmable gate arrays

In this paper, a register smart move method performing placement-aware retiming and replication for sequential circuits implemented in field programmable gate arrays (FPGAs) is presented. This method integrates two major register move operations with circuit functionality unchanged. One operation moves registers across combinational components, called retiming. The other one moves registers across interconnect to reduce critical path delay. Register replication technique is used when the fanout of register to be moved is larger than one. Move budget is defined and used to guide the moves. An incremental placement is used to place retimed or replicated registers. Experiments show that the smart move method proposed in this paper can effectively reduce the path delay, achieving 16% in average of the maximum frequency for sequential circuits implemented in FPGAs.