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 described. The system is hierarchical and deals simultaneously with both placement and global routing. The placement method uses a constructive force-directed algorithm based on an analogy with an electrostatic physical model. In contrast to conventional methods, this is able to take into account the effects of placement on future routing. The integration of placement and global routing gives good results since it considers all the physical aspects of sea-of-gates (geometrical and topological) simultaneously, e.g. connectivity and area optimisation. A prototype of the system has been developed. An example is presented which demonstrates the results achieved in a real design environment and which compare well with existing layout tools