Fast discrete function evaluation using decision diagrams

Abstract

An approach for fast discrete function evaluation based on multi-valued decision diagrams (MDD) is proposed. The MDD for a logic function is translated into a table on, which function evaluation is performed by a sequence of address lookups. The value of a function for a given input assignment is obtained with at most one lookup per input. The main application is to cycle-based logic simulation of digital circuits, where the principal difference from other logic simulators is that only values of the output and latch ports are computed. Theoretically, decision-diagram based function evaluation offers orders-of-magnitude potential speedup over traditional logic simulation methods. In practice, memory bandwidth becomes the dominant consideration on large designs. We describe techniques to optimize usage of the memory hierarchy.