The output file produced by Ifsim consists of a series of lines, each of which indicates the result of injecting a single fault. Each line indicates the following information:
Detected Fault:
node at which the fault was injected.
type of fault (1 for stuck-at-1, 0 for stuck-at-0).
simulation time at which the fault was detected.
the output at which the fault was detected.
Undetected Fault:
the node at which the fault was injected.
type of fault (1 for stuck-at-1, 0 for stuck-at-0).
The list of faults is followed by a summary that includes the following:
The total number of faults seeded.
The number of detected faults.
The number of undetected faults.
The fault coverage as the percentage of detected faults.
The number of probably detected faults.
The last item corresponds to outputs that deviate from the good machine at the time of sampling, but they do so by deviating to or from an X logic state.
For example, the following output file indicates that if NODE1 is stuck-at-0, the fault was detected on output ADR0 at time 250.0ns. Conversely, if NODE1 is stuck-at-1, the fault was not detected. The rest of the entries are similar, except the last one which indicates that if NODE3 is stuck-at-1, the fault was detected as a change from (or to) an X value on output ADR3, at time 600.0ns.
Detect 0 NODE1 [250.0] ADR0
Fail 1 NODE1
Detect 0 NODE2 [450.0] ADR1
Detect 1 NODE2 [350.0] ADR2
Fail 0 NODE3
Maybe 1 NODE3 [600.0] ADR3
— —
6 faults
4 detected (1 probably)
2 undetected
fault coverage: 66.66% (83.33%)