HIERARCHICAL PLACEMENT METHOD BASED ON A FORCE-DIRECTED ALGORITHM WITH SIMULTANEOUS GLOBAL ROUTING FOR SEA-OF-GATES

A new automatic layout system for sea-of-gates architectures is descri bed. The system is hierarchical and deals simultaneously with both pla cement and global routing. The placement method uses a constructive fo rce-directed algorithm based on an analogy with an electrostatic physi cal model. In contrast to conventional methods, this is able to take i nto account the effects of placement on future routing. The integratio n of placement and global routing gives good results since it consider s all the physical aspects of sea-of-gates (geometrical and topologica l) simultaneously, e.g. connectivity and area optimisation. A prototyp e of the system has been developed. An example is presented which demo nstrates the results achieved in a real design environment and which c ompare well with existing layout tools.