Automatic synthesis and technology mapping of combinational logic

SKOL, a system for the synthesis of combinational logic using a library of cells that emphasizes technology-mapping algorithms, is described. It combines current multilevel optimization techniques with a novel approach to technology mapping. Each factor (or the factorized Boolean equation) can be implemented by itself or collapsed into the higher level expression containing it, which is then implemented. An expression can be implemented in several ways, which differ in the degree of factorization. A number of selected implementations is evaluated and the one with minimal cost (area or delay) is chosen. The mapping algorithms are independent of the library of cells, which can be easily modified. Results from benchmark examples were better than or comparable to those for existing systems.<>