Mulga — an interactive symbolic layout system for the design of integrated circuits

To aid the design of MOS circuits, a suite of programs residing on the UNIX^∗ operating system have been designed and written. These programs allow the interactive editing, layout compaction, circuit connectivity extraction, parasitic audit, and timing simulation of MOS ICs within the symbolic domain. The programs make use of an intermediate circuit description language (ICDL), which captures both geometric placement and circuit connectivity. A convenient interface is provided to enable the procedural definition of symbolic layouts in the C programming language. All design may be carried out at a single low-cost work station which incorporates a high-performance color display. In this paper we summarize the operation and use of these programs. In particular, we describe a new compaction algorithm.