New algorithms for the placement and routing of macro cells

Abstract

Novel algorithms are described for timing driven placement and routing of rectilinearly shaped macro cells. Algorithms are also presented for the implementation of simulated annealing, based on a theoretically derived statistical annealing schedule. A negative feedback scheme is described that optimizes the relative weighting between the primary objective term and the penalty function terms in the cost function. A placement refinement method has been developed for rectilinear cells which spaces the cells at a density which avoids the need for post-routing compaction. In addition, a detailed routing method has been developed which avoids the classically difficult problem of defining channels for detailed routing. The result for the ami33 benchmark circuit is better than the previously published results.<>