Incremental autojogging using range spaces

Abstract

A method for automatically jogging wires to reduce layout area during compaction is described. The method operates incrementally and iteratively by jogging only those wires on the critical path that allow layout area to be reduced. Our modular implementation allows the same algorithm to be effectively used for overconstraint resolution by jogging wires. A novel range space based selection approach provides a theoretical basis for jogpoint selection. This method provides a global view during jogpoint selection that eliminates unnecessary jogs and provides consistency between jog locations on adjacent wires. Our system has been successfully applied to extremely large industrial test cases. Due to its incremental nature and its ability to avoid unnecessary jogs, our method can handle large layouts beyond the capability of existing exhaustive jogging methods.