The Magic VLSI Layout System

Magic is a new IC layout system that includes several facilities traditionally contained in separate batch-processing programs. Magic incorporates expertise about design rules, connectivity, and routing directly into the layout editor and uses this information to provide several unusual features. They include a continuous design-rule checker that operates in background and maintains an up-to-date picture of violations; a hierarchical circuit extractor that only re-extracts portions of the circuit that have changed; an operation called plowing that permits interactive stretching and compaction; and a suite of routing tools that can work under and around existing connections in the channels. A design style called logs and a data structure called corner stitching are used to achieve an efficient implementation of the system.