Structured Placement with Topological Regularity Evaluation

Abstract

This paper introduces a new concept of regularity-oriented floorplanning and block placement — structured placement, it takes the regularity as a criterion of placement so as to improve the performance. We provide the methods to extract regular structures from a placement representation in linear time, and manage to evaluate these structures by quantifying the regularity as an objective function. We also construct a particular simulated annealing framework, which optimizes placement topology and physical dimension separately and alternately so that it attains a solution balancing the trade-off between regularity and area efficiency. Furthermore, we introduce the symmetry-oriented structured placement to produce symmetrical placement. Experiments show that the resultant placements achieve regularity without increased chip area and wire length, compared to those by existing methods.