Error propagation path extraction system, error propagation path extraction method, and recording medium recording error propagation path extraction control program
First Claim
1. An error propagation path extraction system for extracting an error propagation path through an inverse logical inference system for estimating the logical state of the input terminal of a combinational circuit in accordance with the logical state of the output terminal of the circuit by using a back track system for estimating the logical state of every signal line by repeating the implication for estimating the logical state of the input/output line of a gate not estimated yet in accordance with the logical state of the input/output line of a gate already estimated;
- the system comprising;
error propagation path influenced line retrieval means for retrieving a signal line connected with said error propagation path as said signal line whose logical state is an object to be decided; and
failing output terminal connection related line extraction means for extracting a signal line having a possibility of propagating an error to a failing output terminal from said error propagation path in accordance with the retrieval result by said error propagation path influenced line retrieval means.
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Accused Products
Abstract
To realize high-speed error propagation path extraction in a combinational circuit, a logical contradiction judgment section detects the logical state of each signal line under the implication by a first implication section and judges whether the logical state of every signal line is estimated as “0,” “1,” or “X” unless a contradiction is detected. When it is judged that logical state estimation is not completed, a U(Unknown)-state retrieval section retrieves an Unknown-state signal line whose logical state is incomplete and retrieves a signal line connected to an error propagation path through a gate. A detected signal line is decided as “0,” a decision level showing a decision frequency is increased by 1, and implication is restarted by a first implication section. It is judged that logical state estimation is completed, a failing output terminal connection related line extraction section extracts an error propagation path directly influencing a failing output terminal and outputs the route to an output unit.
47 Citations
12 Claims
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1. An error propagation path extraction system for extracting an error propagation path through an inverse logical inference system for estimating the logical state of the input terminal of a combinational circuit in accordance with the logical state of the output terminal of the circuit by using a back track system for estimating the logical state of every signal line by repeating the implication for estimating the logical state of the input/output line of a gate not estimated yet in accordance with the logical state of the input/output line of a gate already estimated;
- the system comprising;
error propagation path influenced line retrieval means for retrieving a signal line connected with said error propagation path as said signal line whose logical state is an object to be decided; and
failing output terminal connection related line extraction means for extracting a signal line having a possibility of propagating an error to a failing output terminal from said error propagation path in accordance with the retrieval result by said error propagation path influenced line retrieval means. - View Dependent Claims (2, 3, 4)
- the system comprising;
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5. An error propagation path extraction method for extracting an error propagation path through an inverse logical inference system for estimating the logical state of the input terminal of a combinational circuit in accordance with the logical state of the output terminal of the circuit by using the back track system for estimating the logical state of every signal line by repeating the implication for estimating the logical state of the input/output line of a gate not estimated yet in accordance with the logical state of the input/output line of a gate already estimated, the method comprising the steps of:
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retrieving a signal line connected with said error propagation path as said signal line whose logical state is an object to be decided; and
extracting a signal line having a possibility of propagating an error to a failing output terminal from said error propagation path in accordance with the retrieval result by said error propagation path influenced line retrieval means. - View Dependent Claims (6, 7, 8)
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- 9. A recording medium adapted to record an error propagation path extraction control program for extracting an error propagation path with the inverse logical inference system for estimating the logical state of the input terminal of a combinational circuit in accordance with the logical state of the output terminal of the circuit by using a back track system for estimating the logical state of every signal line by repeating the implication for estimating the logical state of the input/output line of a gate not estimated yet in accordance with the logical state of the input/output line of a gate already estimated and the logical state decision, wherein said error propagation path extraction control program makes control means for controlling extraction of said error propagation path retrieve a signal line connected with said error propagation path as said signal line whose logical state is an object to be decided and extract a signal line having a possibility of propagating an error to a failing output terminal from said error propagation path in accordance with the retrieval result by an error propagation path influence line retrieval means.
Specification