Register Depopulation and Repopulation for Accurate IC Delay Optimization
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Solution Overview
Problem
Performing register retiming before placement or routing operations in integrated circuit design leads to suboptimal solutions due to estimation-based delays, requiring updates to previously determined placement or routing solutions.
Innovation Solution
Implementing depopulation and repopulation operations, where depopulation anticipates potential register retiming by eliminating registers from the circuit design before placement or routing, and repopulation inserts these registers back after routing, using pipelined routing resources configured to operate in non-pipeline and pipeline register modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If register retiming is performed before placement operations, then the register distribution can be balanced based on estimated delays, but the actual delays between registers may be suboptimal due to estimation inaccuracies
Solution Approach 1:
The patent removes registers from the circuit design before placement and routing operations (preliminary action), then adds them back after routing is complete. This allows placement and routing to proceed without registers, avoiding the need to update placement solutions later, while still enabling register retiming optimization after accurate delay measurements are available from the routed design.
2Ease of operation
If register retiming is performed before routing operations, then the register placement can be optimized based on Manhattan distance estimates, but the actual routing delays may be longer due to routing blockages
Solution Approach 1:
The patent removes registers before routing operations, allowing routing to complete without needing to accommodate register placements. After routing is complete, registers are added back to the design, enabling register retiming based on actual routing delays rather than Manhattan distance estimates, thus avoiding suboptimal solutions due to routing blockages.
3Measurement precision
If register retiming is performed after placement operations, then the placement solution may need to be updated, but this increases the complexity and time of the overall design process
Solution Approach 1:
The patent removes registers from the design before placement operations, so that placement can complete without needing to be updated later for register retiming. After placement and routing are complete, registers are added back to the design, enabling register retiming optimization without requiring updates to the already-determined placement solution, thus reducing design process complexity.
Data Source
AI summary
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.