Method and system for creating electronic circuitry

• US 6,327,557 B1
• Filed: 06/04/1998
• Issued: 12/04/2001
• Est. Priority Date: 06/04/1998
• Status: Expired due to Term

• Current Assignee: Synopsys Incorporated
• Original Assignee: Silicon Metrics Corp. (Synopsys Incorporated)
• Inventors: Croix, John Francis
• Primary Examiner(s): Teska, Kevin J.
• Assistant Examiner(s): Broda, Samuel
• Application Number:
  US09/090,457
• Time in Patent Office: 1,279 Days
• Field of Search: 395/500.02, 395/500.23, 395/500.35, 703/2, 703/13, 703/14, 716/1
• US Class Current: 703/14
• CPC Class Codes: G06F 30/33 Design verification, e.g. functional simulation or model checking

Abstract

According to a first model of an operation of circuitry, a first set of estimates of the operation is generated in response to a set of conditions, including a first estimate of the operation in response to a first condition. According to a second model of the operation, a second set of estimates of the operation is generated in response to the first condition and the first set. In response to a comparison between the first estimate and the second set, a subset of the first set is selected. According to the second model, an estimate of the operation is generated in response to a second condition and the selected subset.

Claims

1. A system for modeling an operation of circuitry, comprising:

a computer for;

according to a first model of the operation of the circuitry, generating a first set of estimates of the operation of the circuitry in response to a set of circuitry conditions, including generating a first estimate of the operation of the circuitry in response to a first circuitry condition;

according to a second model of the operation of the circuitry, generating a second set of estimates of the operation of the circuitry in response to the first circuitry condition and to the first set of estimates of the operation of the circuitry, wherein the second model of the operation of the circuitry includes a characteristic equation;

in response to a comparison between the first estimate of the operation of the circuitry and the second set of estimates of the operation of the circuitry, selecting a subset of the first set of estimates of the operation of the circuitry; and

outputting information representing the selected subset in response to which, according to the second model of the operation of the circuitry, the operation of the circuitry is representable within a circuitry design having a second circuitry condition.

2. The system of claim 1 wherein the first model includes a circuit simulator.

3. The system of claim 1 wherein the second model includes a characterization table that includes the characteristic equation.

4. The system of claim 1 wherein the second model is a static timing analysis model including the characteristic equation.

5. The system of claim 1 wherein the computer is for generating the second set by:

determining respective sets of constant elements of the characteristic equation in response to subsets of the first set; and

according to the characteristic equation, in response to the first circuitry condition, generating the second set including respective estimates of the operation in response to the sets of constant elements.

6. The system of claim 5 wherein the computer is for selecting the selected subset from among the subsets of the first set in response to the comparison, the comparison being a comparison between the first estimate and the estimates of the second set.

7. The system of claim 6 wherein:

the subsets of the first set are respectively associated with the sets of constant elements, so the selected subset of the first set is associated with a particular set of constant elements;

the estimates of the second set are respectively associated with the sets of constant elements, so a particular estimate of the second set is associated with the particular set of constant elements; and

among the estimates of the second set, the particular estimate is closest to the first estimate.

8. The system of claim 1 wherein the operation is a response time of the circuitry.

9. The system of claim 1 wherein the operation is a propagation delay of the circuitry.

10. The system of claim 1 wherein the circuitry conditions include at least two types of circuitry conditions.

11. The system of claim 1 wherein the circuitry conditions include at least three types of circuitry conditions.

12. The system of claim 1 wherein the circuitry conditions include capacitive loadings of the circuitry.

13. The system of claim 1 wherein the circuitry conditions include input transition times of the circuitry.

14. The system of claim 13 wherein the circuitry conditions include at least two types of input transition times of the circuitry.

15. The system of claim 1 wherein the circuitry is integrated circuitry.

16. A method performed by a computer for modeling an operation of circuitry, the method comprising:

according to a first computer-implemented model of the operation of the circuitry, generating a first set of estimates of the operation of the circuitry in response to a set of circuitry conditions, including generating a first estimate of the operation of the circuitry in response to a first circuitry condition;

according to a second computer-implemented model of the operation of the circuitry, generating a second set of estimates of the operation of the circuitry in response to the first circuitry condition and to the first set of estimates of the operation of the circuitry, the second computer-implemented model of the operation of the circuitry including a characteristic equation;

in response to a comparison between the first estimate of the operation of the circuitry and the second set of estimates of the operation of the circuitry, selecting a subset of the first set of estimates of the operation of the circuitry; and

outputting information representing the selected subset in response to which, according to the second computer-implemented model of the operation of the circuitry, the operation of the circuitry is representable within a circuitry design having a second circuitry condition.

17. The method of claim 16 wherein the generating of the first set of estimates comprises:

according to the first computer-implemented model of the operation, generating the first set of estimates of the operation in response to the set of circuitry conditions, the first computer-implemented model including a circuit simulator.

18. The method of claim 16 wherein the generating of the second set of estimates comprises:

according to the second computer-implemented model of the operation, generating the second set of estimates, the second computer-implemented model including a characterization table that includes the characteristic equation.

19. The method of claim 16 wherein the generating of the second set of estimates comprises:

according to the second computer-implemented model of the operation, generating the second set of estimates, the second computer-implemented model being a static timing analysis model including the characteristic equation.

20. The method of claim 16 wherein the generating of the second set of estimates comprises:

determining respective sets of constant elements of the characteristic equation in response to subsets of the first set; and

according to the characteristic equation, in response to the first circuitry condition, generating the second set including respective estimates of the operation in response to the sets of constant elements.

21. The method of claim 20 wherein the selecting of the subset comprises:

selecting the selected subset from among the subsets of the first set in response to the comparison, the comparison being a comparison between the first estimate and the estimates of the second set.

22. The method of claim 21 wherein the selecting of the subset comprises:

selecting the selected subset from among the subsets of the first set in response to the comparison,

the subsets of the first set being respectively associated with the sets of constant elements, so the selected subset of the first set is associated with a particular set of constant elements;

the estimates of the second set being respectively associated with the sets of constant elements, so a particular estimate of the second set is associated with the particular set of constant elements; and

among the estimates of the second set, the particular estimate being closest to the first estimate.

23. The method of claim 16 wherein the generating of the first set of estimates comprises:

according to the first computer-implemented model of the operation, generating the first set of estimates of the operation in response to the set of circuitry conditions, the operation being a response time of the circuitry.

24. The method of claim 16 wherein the generating of the first set of estimates comprises:

according to the first computer-implemented model of the operation, generating the first set of estimates of the operation in response to the set of circuitry conditions, the operation being a propagation delay of the circuitry.

25. The method of claim 16 wherein the generating of the first set of estimates comprises:

according to the first computer-implemented model of the operation, generating the first set of estimates of the operation in response to the set of circuitry conditions, the circuitry conditions including at least two types of circuitry conditions.

26. The method of claim 16 wherein the generating of the first set of estimates comprises:

according to the first computer-implemented model of the operation, generating the first set of estimates of the operation in response to the set of circuitry conditions, the circuitry conditions including at least three types of circuitry conditions.

27. The method of claim 16 wherein the generating of the first set of estimates comprises:

according to the first computer-implemented model of the operation, generating the first set of estimates of the operation in response to the set of circuitry conditions, the circuitry conditions including capacitive loadings of the circuitry.

28. The method of claim 16 wherein the generating of the first set of estimates comprises:

according to the first computer-implemented model of the operation, generating the first set of estimates of the operation in response to the set of circuitry conditions, the circuitry conditions including input transition times of the circuitry.

29. The method of claim 28 wherein the generating of the first set of estimates comprises:

according to the first computer-implemented model of the operation, generating the first set of estimates of the operation in response to the set of circuitry conditions, the circuitry conditions including at least two types of input transition times of the circuitry.

30. The method of claim 16 wherein the generating of the first set of estimates comprises:

according to the first computer-implemented model of the operation, generating the first set of estimates of the operation in response to the set of circuitry conditions, the circuitry being integrated circuitry.

31. A computer program product for modeling an operation of circuitry, the computer program product comprising:

a computer application processable by a computer for causing the computer to;

according to a first model of the operation of the circuitry, generate a first set of estimates of the operation of the circuitry in response to a set of circuitry conditions, including generating a first estimate of the operation of the circuitry in response to a first circuitry condition;

according to a second model of the operation of the circuitry, generate a second set of estimates of the operation of the circuitry in response to the first circuitry condition and to the first set of estimates of the operation of the circuitry, wherein the second model of the operation of the circuitry includes a characteristic equation;

in response to a comparison between the first estimate of the operation of the circuitry and the second set of estimates of the operation of the circuitry, select a subset of the first set of estimates of the operation of the circuitry; and

output information representing the selected subset in response to which, according to the second model of the operation of the circuitry, the operation of the circuitry is representable within a circuitry design having a second circuitry condition; and

apparatus from which the computer application is accessible by the computer.

32. A computer program product of claim 31 wherein the first model includes a circuit simulator.

33. A computer program product of claim 31 wherein the second model includes a characterization table that includes the characteristic equation.

34. The computer program product of claim 31 wherein the second model is a static timing analysis model including the characteristic equation.

35. The computer program product of claim 31 wherein the computer application is processable by the computer for causing the computer to generate the second set by:

determining respective sets of constant elements of the characteristic equation in response to subsets of the first set; and

according to the characteristic equation, in response to the first circuitry condition, generating the second set including respective estimates of the operation in response to the sets of constant elements.

36. The computer program product of claim 35 wherein the computer application is processable by the computer for causing the computer to select the selected subset from among the subsets of the first set in response to the comparison, the comparison being a comparison between the first estimate and the estimates of the second set.

37. The computer program product of claim 36 wherein:

the subsets of the first set are respectively associated with the sets of constant elements, so the selected subset of the first set is associated with a particular set of constant elements;

the estimates of the second set are respectively associated with the sets of constant elements, so a particular estimate of the second set is associated with the particular set of constant elements; and

among the estimates of the second set, the particular estimate is closest to the first estimate.

38. The computer program product of claim 31 wherein the operation is a response time of the circuitry.

39. The computer program product of claim 31 wherein the operation is a propagation delay of the circuitry.

40. The computer program product of claim 31 wherein the circuitry conditions include at least two types of circuitry conditions.

41. The computer program product of claim 31 wherein the circuitry conditions include at least three types of circuitry conditions.

42. The computer program product of claim 31 wherein the circuitry conditions include capacitive loadings of the circuitry.

43. The computer program product of claim 31 wherein the circuitry conditions include input transition times of the circuitry.

44. The computer program product of claim 43 wherein the circuitry conditions include at least two types of input transition times of the circuitry.

45. The computer program product of claim 31 wherein the circuitry is integrated circuitry.

46. A system for modeling an operation of circuitry, comprising:

a computer for;

according to a first model of the operation of the circuitry, generating a first set of estimates of the operation of the circuitry in response to a set of circuitry conditions, including generating a first estimate of the operation of the circuitry in response to a first circuitry condition;

according to a second model of the operation of the circuitry, generating a second set of estimates of the operation of the circuitry in response to the first circuitry condition and to the first set of estimates of the operation of the circuitry, wherein the second model of the operation of the circuitry includes a characteristic equation;

in response to a comparison between the first estimate of the operation of the circuitry and the second set of estimates of the operation of the circuitry, selecting a subset of the first set of estimates of the operation of the circuitry; and

in response to information representing the selected subset, according to the second model of the operation of the circuitry, representing the operation of the circuitry within a circuitry design having a second circuitry condition.

47. A method performed by a computer for modeling an operation of circuitry, the method comprising:

according to a first computer-implemented model of the operation of the circuitry, generating a first set of estimates of the operation of the circuitry in response to a set of circuitry conditions, including generating a first estimate of the operation of the circuitry in response to a first circuitry condition;

according to a second computer-implemented model of the operation of the circuitry, generating a second set of estimates of the operation of the circuitry in response to the first circuitry condition and to the first set of estimates of the operation of the circuitry, the second computer-implemented model including a characteristic equation;

in response to a comparison between the first estimate of the operation of the circuitry and the second set of estimates of the operation of the circuitry, selecting a subset of the first set of estimates of the operation of the circuitry; and

in response to information representing the selected subset, according to the second computer-implemented model of the operation of the circuitry, representing the operation of the circuitry within a circuitry design having a second circuitry condition.

48. A computer program product for modeling an operation of circuitry, the computer program product comprising:

a computer application processable by a computer for causing the computer to;

according to a first model of the operation of the circuitry, generate a first set of estimates of the operation of the circuitry in response to a set of circuitry conditions, including generating a first estimate of the operation of the circuitry in response to a first circuitry condition;

according to a second model of the operation of the circuitry, generate a second set of estimates of the operation of the circuitry in response to the first circuitry condition and to the first set of estimates of the operation of the circuitry, wherein the second model of the operation of the circuitry includes a characteristic equation;

in response to a comparison between the first estimate of the operation of the circuitry and the second set of estimates of the operation of the circuitry, select a subset of the first set of estimates of the operation of the circuitry; and

in response to information representing the selected subset, according to the second model of the operation of the circuitry, represent the operation of the circuitry within a circuitry design having a second circuitry condition; and

apparatus from which the computer application is accessible by the computer.