AN EFFICIENT, FORWARD FAULT SIMULATION ALGORITHM BASED ON THE PARALLEL PATTERN SINGLE FAULT PROPAGAT

In this paper, we present a fast fault simulator, FSIM, for combinational circuits. FSIM is based on the parallel pattern single fault propagation (PPSFP) technique. The essential idea of FSIM is to simulate the circuit in the forward levelized order and to prune off unnecessary gates in the early stages. In this way, FSIM performs fault simulations only for the gates which are affected by 'the injected faults. Another key feature employed in FSIM is the use of multiple last-in first-out (L,IFO) stacks instead of the commonly used priority queue [9]. The propagation time of the mult,iple LIFO stacks is O(n) and that of the priority queue O(n log n), where n is the number of gates in the propagation zone of the fault under consideration. The two features achieve a substantial reduction of the processing time. Experimental results for ten benchmark circuits show that FSIM outperforms other competing PPSFP fault simulators, Moreover, the efficiency of FSIM is less dependent on the circuit structure than other fault simulators. Experimental results of FSIM for various packet sizes, i.e., the number of test patterns simulated at a time, are also presented.