Fault simulation for multiple faults by Boolean function manipulation

We propose a fault simulation technique for multiple faults based on a deductive fault simulation method. The main difficulty in the development of a technique for multiple fault simulation is handling a very large number of multiple faults. Conventional deductive simulation using Linear lists to store fault sets is not appropriate for such large sets of multiple faults. Our approach to this problem is to represent sets of multiple faults by Boolean functions. We assign a distinct code word to each multiple fault and represent the fault by a minterm corresponding to its code word. Then, set operations in deductive simulation are replaced by logic operations. As an internal representation of fault sets, we use shared binary decision diagrams. The method of coding multiple faults is a key to efficient simulation. We propose a coding method called FNT coding. We also propose a fault dropping method, called prime fault dropping, which is used efficiently with our multiple fault simulation technique. Experimental results show that our technique effectively handles multiple faults at significantly lower computation cost.<
>