SAT-based resource binding for reducing critical path delays

In this paper, a new function unit binding approach based on SAT is proposed. Differently from previous approaches, which heuristically minimize the total numbers of inputs of multiplexers, the proposed approach generates SAT formulas that constrain the numbers of inputs of specific multiplexers to certain numbers and produces a solution that satisfies the constraints with a SAT solver. The proposed approach is applied to constrain the numbers of inputs of the multiplexers that lie between the input and output registers of multipliers, since these multiplexers are likely to be on critical paths. Experimental comparisons with a traditional approach show that the proposed approach is promising for reducing critical path delays.