Compatible class encoding in Roth-Karp decomposition for two-output LUT architecture

Roth-Karp decomposition is one of the most popular techniques for LUT-based FPGA technology mapping because it can decompose a node into a set of nodes with fewer numbers of fanins. In this paper, we show how to formulate the compatible class encoding problem in Roth-Karp decomposition as a symbolic-output encoding problem in order to exploit the feature of the two-output LUT architecture. Based on this formulation, we also develop an encoding algorithm to minimize the number of LUT's required to implement the logic circuit. Experimental results show that our encoding algorithm can produce promising results in the logic synthesis environment for the two-output LUT architecture.