A hierarchy of multiplexers is provided to generate functions of more inputs than the lookup table can handle. For example, a lookup table having 16 memory cells can generate functions of four input signals. By combining the outputs of two lookup tables in a multiplexer (F5) controlled by a fifth input...http://www.google.es/patents/US6323682?utm_source=gb-gplus-sharePatente US6323682 - FPGA architecture with wide function multiplexers
