Abstract: An integrated circuit design may include registers and combinational logic. Integrated circuit design computing equipment may perform retiming for the circuit design, where registers are moved across one or more portions of the combinational logic. The registers may be retimed while considering hybrid initial states of the registers. At least some of the registers may have don't-care initial states. When performing backward retiming, initial states of the retimed registers may be computed that is consistent with the original initial state and functionality of the combinational logic while maximizing the number of don't-care initial states. When performing forward retiming across non-justifiable combinational elements, any don't-care initial states may be assumed to be equal to a deterministic binary value, and the initial states of the retimed registers may be computed that is consistent with the original initial states and functionality of the combinational logic.

Abstract: Circuit design computing equipment may perform depopulation operations, constraint generation, and repopulation operations in a circuit design in anticipation of register retiming operations. A depopulation operation before placement and/or before routing operations may prevent the respective placement and/or routing operations from placing and/or routing registers from the circuit design. Constraint generation may create constraints for placement and/or routing operations that allow for the reinsertion of registers after routing operations. Repopulation operations may reinsert registers in the circuit design after routing operations according to the constraints. If desired, the circuit design computing equipment may perform register retiming operations to further improve the performance of the circuit design.

Abstract: Circuit design computing equipment may perform depopulation operations, constraint generation, and repopulation operations in a circuit design in anticipation of register retiming operations. A depopulation operation before placement and/or before routing operations may prevent the respective placement and/or routing operations from placing and/or routing registers from the circuit design. Constraint generation may create constraints for placement and/or routing operations that allow for the reinsertion of registers after routing operations. Repopulation operations may reinsert registers in the circuit design after routing operations according to the constraints. If desired, the circuit design computing equipment may perform register retiming operations to further improve the performance of the circuit design.

Abstract: Techniques and mechanisms allow a device such as a programmable logic device (PLD) to support real-time debugging of a system. The PLD may be configured to include a debug design without disturbing the configuration of a base logic design in the PLD.