Method and apparatus for creating simplified false-path description on false path, and computer product

Abstract

An apparatus for creating a simplified false-path description on a false path among paths in a target circuit extracts, from descriptions on the paths, a target path description on a target path. The apparatus judges whether the target path is a false path based on the target path description. The apparatus identifies, when it is judged that the target path is a false path, a sufficient set of elements from elements included in the target path. The settings for causing every element in the sufficient set to transmit a signal conflict. The apparatus creates the simplified false-path description on the false path by deleting, from the target path description, a description on elements that are not included in the sufficient set.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic of a false path according to an embodiment of the present invention;

FIGS. 2A to 2C are schematics of a description on a target path detected as a false path;

FIG. 3 is a schematic of an apparatus for creating a description on a false path;

FIG. 4 is a block diagram of the apparatus for creating a description on a false path;

FIG. 5 is a flowchart of a process of creating a description on a false path performed by the apparatus for creating a description on a false path;

FIG. 6 is a schematic of a false path description set after a minimizing process;

FIG. 7 is a schematic of a target circuit for which the minimizing process of the false path description set is performed;

FIG. 8 is a schematic of the false path description set;

FIG. 9 is a flowchart of a minimizing process of the false path description set shown in FIG. 5; and

FIG. 10 is a schematic of a false path in a target circuit.

Claims

1. A computer-readable recording medium that stores therein a computer program for creating a simplified false-path description on a false path among a plurality of paths in a target circuit, the computer program causing a computer to execute: extracting, from a plurality of descriptions on the paths, a target path description on a target path;judging whether the target path is a false path based on the target path description;identifying, when it is judged that the target path is a false path, a sufficient set of elements from a plurality of elements included in the target path, wherein settings for causing every element in the sufficient set to transmit a signal conflict; andcreating the simplified false-path description on the false path by deleting, from the target path description, descriptions on elements that are not included in the sufficient set.

2. The computer-readable recording medium according to claim 1, wherein: the extracting includes extracting a new target path description on a new target path from the descriptions; andthe judging includes judging whether the new target path is a false path based on whether all the elements in the sufficient set are included in the new target path description.

3. The computer-readable recording medium according to claim 1, wherein the creating includes creating a plurality of simplified false-path descriptions including at least a first simplified false-path description and a second simplified false-path description, andthe computer program further causes the computer to execute: judging whether the first simplified false-path description is identical to the second simplified false-path description; anddeleting, when it is judged that the first simplified false-path description is identical to the second simplified false-path description, either one of the first simplified false-path description and the second simplified false-path description.

4. The computer-readable recording medium according to claim 1, wherein the simplified false-path description includes a description on a proof of a conflict among the elements in the sufficient set.

5. An apparatus that creates a simplified false-path description on a false path among a plurality of paths in a target circuit, the apparatus comprising: an extracting unit that extracts, from a plurality of descriptions on the paths, a target path description on a target path;a first judging unit that judges whether the target path is a false path based on the target path description;an identifying unit that identifies, when it is judged that the target path is a false path, a sufficient set of elements from a plurality of elements included in the target path, wherein settings for causing every element in the sufficient set to transmit a signal conflict; anda creating unit that creates the simplified false-path description on the false path by deleting, from the target path description, descriptions on elements that are not included in the sufficient set.

6. The apparatus according to claim 5, wherein: the extracting unit extracts a new target path description on a new target path from the descriptions; andthe first judging unit judges whether the new target path is a false path based on whether all the elements in the sufficient set are included in the new target path description.

7. The apparatus according to claim 5, wherein the creating unit creates a plurality of simplified false-path descriptions including at least a first simplified false-path description and a second simplified false-path description, andthe apparatus further comprises: a second judging unit that judges whether the first simplified false-path description is identical to the second simplified false-path description; anda deleting unit that deletes, when it is judged that the first simplified false-path description is identical to the second simplified false-path description, either one of the first simplified false-path description and the second simplified false-path description.

8. The apparatus according to claim 5, wherein the simplified false-path description includes a description on a proof of a conflict among the elements in the sufficient set.

9. A method of creating a simplified false-path description on a false path among a plurality of paths in a target circuit, the method comprising: extracting, from a plurality of descriptions on the paths, a target path description on a target path;judging whether the target path is a false path based on the target path description;identifying, when it is judged that the target path is a false path, a sufficient set of elements from a plurality of elements included in the target path, wherein settings for causing every element in the sufficient set to transmit a signal conflict; andcreating the simplified false-path description on the false path by deleting, from the target path description, descriptions on elements that are not included in the sufficient set.

10. The method according to claim 9, wherein the extracting includes extracting a new target path description on a new target path from the descriptions, andthe judging includes judging whether the new target path is a false path based on whether all the elements in the sufficient set are included in the new target path description.

11. The method according to claim 9, wherein the creating includes creating a plurality of simplified false-path descriptions including at least a first simplified false-path description and a second simplified false-path description, andthe method further comprises: judging whether the first simplified false-path description is identical to the second simplified false-path description; anddeleting, when it is judged that the first simplified false-path description is identical to the second simplified false-path description, either one of the first simplified false-path description and the second simplified false-path description.

12. The method according to claim 9, wherein the simplified false-path description includes a description on a proof of a conflict among the elements in the sufficient set.