Failure propagation path estimate system

A failure propagation path estimate method for estimating a logic state and a failure propagation path in a logic circuit by repeating an assumption and an implication operation based on a failure output terminal in the logic circuit, the method comprising:

• a first step of judging whether a present process is an initial estimate process or re-calculation following a measurement, where the re-calculation is performed, when an initial failure location estimate process has already taken place, to reflect the measurement result on the result from the failure location estimate process;
• a second step of searching the failure propagation paths obtained from the previous estimate process;
• a third step of measuring values of nodes in the logic circuit;
• a fourth step of verifying the measured values of the nodes in the logic circuit for each of the searched failure propagation paths, including a path whose logic state is implicated upon confirming the measured value and a path causative of propagating a failure state to the measured value;
• and
• a fifth step of updating the failure propagation path according to the verified results obtained by the fourth step,
• wherein the failure propagation path estimate is then continued based on the verified values.

A storage medium for storing a computer program product to execute a failure propagation path estimate process for estimating a logic state and a failure propagation path in a logic circuit by repeating an assumption and an implication operation of logic values based on a failure output terminal in the logic circuit, the process comprising:

• a re-calculation judging step for judging whether a present process is an initial estimate process or re-calculation following a measurement, where the re-calculation is performed, when an initial failure location estimate process has already taken place, to reflect the measurement result on the result obtained from the failure location estimate process;
• a failure propagation path searching step for searching the failure propagation paths obtained from the previous estimate process;
• a measurement point neighborhood implication operation step for verifying measured values of nodes in the logic circuit for each of the searched failure propagation paths, including a path whose logic state is implicated upon confirming the measured value of the nodes and a path causative of propagating a failure state to the measured value;
• and
• a failure propagation path updating step for updating the failure propagation path according to the verified results,
• wherein the failure propagation path estimate is then continued based on the verified values.

A storage medium for storing a computer program product to execute a failure propagation path estimate process for estimating a logic state and a failure propagation path in a logic circuit by repeating an assumption and an implication operation of logic values based on a failure output terminal in the logic circuit, where re-calculation is performed, when an initial failure location estimate process has already taken place, to reflect the measurement result on the result obtained from the failure location estimate process, wherein, when an actual measurement value of a measured value of a node in the logic circuit is a normal value identical to the expected value, the failure propagation path estimate process further comprises:

• an input-direction critical path searching step in which the failure propagation paths are traced in the input direction using the measured value as a basic point, and measured values of the node propagating the failure state to the measured value are changed to values that does not contradict with the actual measurement value of the measured value;
• and
• a contradicting path deleting step for deleting the failure propagation path information that contradicts, with the actual measurement value of the measured value,
• wherein the failure propagation path estimate is then continued based on the measured values.

A storage medium for storing a computer program product capable of executing a failure propagation path estimate method, the method comprising:

• a first step of judging whether a present process is an initial estimate process or re-calculation following a measurement, where the re-calculation is performed, when an initial failure location estimate process has already taken place, to reflect the measurement result on the result from the failure location estimate process;
• a second step of searching failure propagation paths obtained from the previous estimate process;
• a third step of measuring values of nodes in a logic circuit;
• a fourth step of verifying measured values of the nodes for each of the searched failure propagation paths, including a path whose logic state is implicated upon confirming the measured value and a path causative of propagating a failure state to the measured value;
• and
• a fifth step of updating the failure propagation path according to the verified results obtained by the fourth step,
• wherein the failure propagation path estimate is then continued based on the verified values.