Heuristic Synthesis of Multi-Terminal BDDs Based on Local Width/Cost Minimization

Multi-terminal binary decision diagrams (MTBDDs) are useful representation of multiple output Boolean functions. However, construction of such a diagram is a difficult task, especially when in some sense optimum diagram is sought. The paper presents an improved algorithm of MTBDD synthesis aiming at minimum MTBDD width or cost. The presented algorithm is a core of the upgraded version of a synthesis tool that accepts incompletely specified integer-valued functions of Boolean variables specified by possibly compatible cubes. The suggested technique is suitable for hardware (LUT cascades) or firmware implementation (branching microprograms).