Unified functional decomposition via encoding for FPGA technology mapping

Functional decomposition has recently been adopted for look-up tabel (LUT)- based field-programmable gate array (FPGA) technology mapping with good res ults. In this paper we propose a novel method to unify functional single;ou tput and multiple-output decomposition. We first address a compatible class encoding algorithm to minimize the number of compatible classes in the ima ge function. After applying the encoding algorithm, we can therefore improv e the decomposability in the subsequent decomposition of the; image functio n. The above encoding algorithm is then extended to encode multiple-output functions through the construction of a hyperfunction, Common subexpression s among these multiple-output functions can be extracted during the decompo sition of the hyperfunction, Consequently, we can handle multiple-output de composition in the same manner as single-output decomposition. Experimental results show that our algorithms are promising.