EC-Pl: an Integrated Circuit Layout Program in the Enhanced C Language

We have designed and implemented a system called EC-PI that automatically lays out integrated circuits. EC-PI provides a test bed for layout algorithms. It is also designed as an experiment in using very high level programming languages for the implementation of such algorithms. This paper reports the structure and performance of the system its well as our conclusions from developing and using it. FGPI partitions the layout process into several steps: cell placement, pad placement, routing power and ground nets in a single-metal layer, channel definition, global routing, crossing placement, and switch-box routing. This partition follows the MIT PI Placemant and Interconnat system [13], however, the implementation of the steps differs and includes several novel techniques. Among these techniques are a new cost function for cell placement, a simple and efficient algorithm for pad placing, a new algorithm for channel definition, and a new implementation of PI's global routing algorithm. Several layout examples illustrating the performance of the system are given in appendix A. The layout program is implemented using the Enhanced C (EC) programming language. The work presents conclusions related to both the layout process and use of the EC language.