Soft macro cell generation by two dimensional folding

The authors present a macro cell generator for flexible multilevel nMOS NOR arrays. A two-dimensional column and row folding algorithm optimizes area usage and cell shape. The accurate control of the shape is realized in combination with top down floorplanning. Compared to programmable logic arrays, the cell generator allows for multilevel logic decomposition, and generates denser and more flexible layouts. The folding algorithm uses an elegant hierarchical divide and conquer technique, and produces results that are 59% smaller than those of a simulated annealing approach