Efficient presentation of functional coverage results

• US 20060229860A1
• Filed: 04/07/2005
• Published: 10/12/2006
• Est. Priority Date: 04/07/2005
• Status: Active Grant

• Current Assignee: GlobalFoundries, Inc.
• Original Assignee: International Business Machines Corporation
• Inventors: Ziv, Avi, Ur, Shmuel, Marcus, Eitan, Zohar, Keren, Azatchi, Yehezkel
• Granted Patent: US 7,389,215 B2
• Time in Patent Office: Days
• US Class Current: 703/14
• CPC Class Codes: G06F 11/3676 for coverage analysis
• CPC Class Codes: G06F 30/20 Design optimisation, verification or simulation optimisation, verification or simulation of circuit designs G06F30/30

Abstract

A method for presentation of functional coverage includes representing a set of attributes of a design under test as a multi-dimensional cross-product space, which includes events corresponding to combinations of values of the attributes to be tested, the events including legal and illegal events. At least one test is run on the design, and responsively to the at least one test, a first group of the legal events that were covered by the at least one test and a second group of the legal events that remain non-covered after the at least one test are identified. One or more of the illegal events are grouped with at least one of the first and second groups so as to present a simplified model of the coverage of the events in the cross-product space.

Claims

1. A method for presentation of functional coverage, comprising:

representing a set of attributes of a design under test as a multi-dimensional cross-product space, comprising events corresponding to combinations of values of the attributes to be tested, the events comprising legal and illegal events;

running at least one test on the design;

identifying, responsively to the at least one test, a first group of the legal events that were covered by the at least one test and a second group of the legal events that remain non-covered after the at least one test; and

grouping one or more of the illegal events with at least one of the first and second groups so as to present a simplified model of the coverage of the events in the cross-product space.

2. The method according to claim 1, wherein identifying the first group comprises analyzing a trace of the at least one test in order to identify the events that were covered by the at least one test.

3. The method according to claim 1, wherein grouping the one or more of the illegal events comprises presenting at least one of a coverage hole and a coverage block in the cross-product space.

4. The method according to claim 3, wherein grouping the one or more of the illegal events comprises grouping at least one of the illegal events into the first group, and aggregating the events in the second group after grouping the at least one of the illegal events into the first group in order to present at least one of the coverage hole and the coverage block.

5. The method according to claim 3, wherein grouping the one or more of the illegal events comprises grouping at least one of the illegal events into the second group, and aggregating the events in the second group after grouping the at least one of the illegal events into the second group in order to present at least one of the coverage hole and the coverage block, whereby the coverage hole contains one or more of the illegal events.

6. The method according to claim 5, wherein aggregating the events in the second group comprises determining how to present the coverage hole responsively to a distribution of the illegal events in the coverage holes.

7. The method according to claim 6, wherein determining how to present the coverage hole comprises determining a density of the illegal events in one or more coverage holes, and selecting for presentation at least one of the coverage holes for which the density of the illegal events is less than a predetermined percentage.

8. The method according to claim 1, and comprising grouping one or more of the covered events with the second group in presenting the simplified model of the coverage in the cross-product space.

9. A method for presentation of functional coverage, comprising:

representing a set of attributes of a design under test as a multi-dimensional cross-product space, comprising events corresponding to combinations of values of the attributes to be tested;

running at least one test on the design;

identifying, responsively to the at least one test, a first group of the events that were covered by the at least one test and a second group of the events that remain non-covered after the at least one test; and

grouping one or more of the covered events with the second group so as to present a simplified model of the coverage of the events in the cross-product space.

10. The method according to claim 9, wherein grouping the one or more of the covered events comprises aggregating the events in the second group in order to present one or more coverage holes.

11. Apparatus for presentation of functional coverage, comprising:

a coverage processor, which is arranged to represent a set of attributes of a design under test as a multi-dimensional cross-product space, comprising events corresponding to combinations of values of the attributes to be tested, the events comprising legal and illegal events, and which is further arranged to identify, responsively to running at least one test on the design, a first group of the legal events that were covered by the at least one test and a second group of the legal events that remain non-covered after the at least one test, and to group one or more of the illegal events with at least one of the first and second groups so as to generate a simplified model of the coverage of the events in the cross-product space; and

an output device, which is coupled to the coverage processor so as to present the simplified model to a user.

12. The apparatus according to claim 11, wherein the coverage processor is arranged to generate the simplified model so as to present at least one of a coverage hole and a coverage block in the cross-product space.

13. The apparatus according to claim 12, wherein the coverage processor is arranged to group at least one of the illegal events into the first group, and to aggregate the events in the second group after grouping the at least one of the illegal events into the first group in order to present at least one of the coverage hole and the coverage block in the cross-product space.

14. The apparatus according to claim 12, wherein the coverage processor is arranged to group at least one of the illegal events into the second group, and to aggregate the events in the second group after grouping the at least one of the illegal events into the second group in order to present at least one of the coverage hole and the coverage block in the cross-product space, whereby the coverage hole contains one or more of the illegal events.

15. The apparatus according to claim 14, wherein the coverage processor is arranged to determine how to present the coverage hole responsively to a distribution of the illegal events in the coverage holes.

16. The apparatus according to claim 15, wherein the coverage processor is arranged to determine a density of the illegal events in one or more coverage holes, and to select for presentation at least one of the coverage holes for which the density of the illegal events is less than a predetermined percentage.

17. The apparatus according to claim 11, wherein the coverage processor is arranged to group one or more of the covered events with the second group in presenting the simplified model of the coverage in the cross-product space.

18. A computer software product for presentation of functional coverage, the product comprising a computer-readable medium in which program instructions are stored, which instructions, when read by a computer, cause the computer to represent a set of attributes of a design under test as a multi-dimensional cross-product space, comprising events corresponding to combinations of values of the attributes to be tested, the events comprising legal and illegal events, and further cause the computer to identify, responsively to running at least one test on the design, a first group of the legal events that were covered by the at least one test and a second group of the legal events that remain non-covered after the at least one test, and to group one or more of the illegal events with at least one of the first and second groups so as to present a simplified model of the coverage of the events in the cross-product space.

19. The product according to claim 18, wherein the instructions cause the computer to generate the simplified model so as to present at least one of a coverage hole and a coverage block in the cross-product space.

20. The product according to claim 19, wherein the instructions cause the computer to group at least one of the illegal events into the first group, and to aggregate the events in the second group after grouping the at least one of the illegal events into the first group in order to present at least one of the coverage hole and the coverage block in the cross-product space.

21. The product according to claim 19, wherein the instructions cause the computer to group at least one of the illegal events into the second group, and to aggregate the events in the second group after grouping the at least one of the illegal events into the second group in order to present at least one of the coverage hole and the coverage block in the cross-product space, whereby the coverage hole contains one or more of the illegal events.

22. The product according to claim 21, wherein the instructions cause the computer to determine how to present the coverage hole responsively to a distribution of the illegal events in the coverage holes.

23. The product according to claim 22, wherein the instructions cause the computer to determine a density of the illegal events in one or more coverage holes, and to select for presentation at least one of the coverage holes for which the density of the illegal events is less than a predetermined percentage.

24. The product according to claim 18, wherein the instructions cause the computer to group one or more of the covered events with the second group in presenting the simplified model of the coverage in the cross-product space.