Technique for 1-dimensional VLSI layout generation

The layout and synthesis system RESCUE presented by Shaw et al. (1986) is briefly reviewed. It is a system for implementing random logic using an array layout style. RTL equations are realised by a horizontal row of cells which may contain both static and dynamic circuits. Signals are carried by polysilicon lines in horizontal rows. Algorithmic improvements are suggested in three areas. First, the mincut algorithm is proposed for the cell-assignment problem. Secondly, a new algorithm is presented which determines a placement for the polysilicon lines in a way that allows narrower cells to be designed. Another algorithm based on a technique developed by the authors is proposed for designing cells so as to optimise their areas. The complexity of the final set of algorithms is O(E log E) where E is the number of RTL equations. Improvements range from 5.5% to 50%