According to some embodiments, arithmetic structures in logic elements result from combining inverters and pass gates (or other multiplexing hardware) with LUT hardware. According to other embodiments, arithmetic structures in logic elements result from combining dedicated adder hardware (e.g., including...http://www.google.com.hk/patents/US7185035?utm_source=gb-gplus-share專利 US7185035 - Arithmetic structures for programmable logic devices
