Electronic Design Automation

6.3.3. Multilevel logic minimization

Two-level logic is limited because not all Boolean functions can be efficiently represented in the SOP form. Multilevel logic implementation of a function is often faster and smaller than two-level logic. Therefore multilevel realizations are the preferred means of implementing combinational logic in very large scale integrated (VLSI) systems. Because of the increased potential for reusing sub-circuits, there are more degrees of freedom in implementing a Boolean function than in the two-level case. This increased freedom, however, largely expands the search space in identifying an optimal solution.

The area of multilevel logic synthesis has blossomed since the mid-1980s. Many of the methods developed have ...