Unformatted text preview: X ; 2: JustifyFanoutFree ±C²g² v³ ; /* excite the fault by justifying line g to v */ 3: PropagateFanoutFree ±C²g³ ; /* propagate fault-effect from g to a PO */ The JustifyFanoutFree ±g²v³ function recursively justifies the predecessor signals of g until all signals that need to be justified are indeed justified from the primary inputs. The simple outline of the JustifyFanoutFree routine is listed in Algorithm 3. In line #10 of the algorithm, controllability measures can be used to select the best input to justify. Selecting a good gate input may help to reach a primary input sooner. Consider the circuit C shown in Figure 4.9. Suppose the objective is to justify g = 1. According to the above algorithm, the following sequence of recursive calls to JustifyFanoutFree() would have been made: a h z g f b c d ± FIGURE 4.9 Example fanout-free circuit....
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- Spring '08
- Recursion, Basic ATPG Algorithm