Multi-output functional decomposition with exploitation of don´t cares

Functional decomposition is an important technique in logic synthesis, especially for the design of lookup table based FPGA architectures. We present a method for functional decomposition with a novel concept for the exploitation of don´t cares thereby combining two essential goals. The minimization of the number of decomposition functions in the current decomposition step and the extraction of common subfunctions for multi-output Boolean functions. The exploitation of symmetries of Boolean functions plays an important role in our algorithm as a means to minimize the number of decomposition functions not only for the current decomposition step but also for the (recursive) decomposition algorithm as a whole. Experimental results prove the effectiveness of our approach