Technology mapping via transformations of function graphs

The authors address the problem of how to realize a given combinational circuit described by means of Boolean equations using the minimum number of blocks of the target TLU table lookup architecture. Their Boolean decomposition scheme works directly on a reduced ordered binary decision diagram (ROBDD) of a subject function, using two techniques. The first, referred to as cutting, is an efficient implementation of Roth-Karp decomposition. The second technique is referred to as a substitution. The idea is to replace subgraphs of ROBDD by new variables. The substitution process is accompanied by certain reductions of the resulting ROBDD graph, which further decreases its size.<>