TIMING INFLUENCED GENERAL-CELL GENETIC FLOORPLANNER

In this paper we present a timing-influenced floorplanner for general cell IC design. The floorplanner works in two phases. In the first pha se we use the genetic algorithm and restrict the modules to be rigid a nd the floorplan to have slicing structure. This restriction results i n a simple and elegant encoding, as well as large savings in run time. In this phase the search is directed toward floorplans that better sa tisfy timing constraints on the critical paths and delay bounds on all the nets. The objective function also incorporates area and wire-leng th. The second phase allows modification to the aspect ratios of indiv idual modules to reduce further the area of the overall bounding box. This phase is constraint graph based. The approach combines the robust ness of genetic algorithm with run time efficiency and elegance of con straint graph based method. Experimental results are presented. (C) 19 97 Elsevier Science Ltd.