Modifying a design to reveal the data flow of the design in order to create a more favorable input for block placement

• US 20050183054A1
• Filed: 06/07/2004
• Published: 08/18/2005
• Est. Priority Date: 02/17/2004
• Status: Active Grant

• Current Assignee: Synopsys Incorporated
• Original Assignee: Synopsys Incorporated
• Inventors: Wein, Enno, Panda, Uma, Poghosyan, Vahagn
• Granted Patent: US 7,269,815 B2
• Time in Patent Office: Days
• US Class Current: 716/105
• CPC Class Codes: G06F 30/392 Floor-planning or layout, e.g. partitioning or placement

Abstract

A system is employed for modifying a hierarchical description of a design to reveal the data flow of the design. The modified design provides a more favorable input for block placement. In one embodiment, the modifications includes any one of or a combination of moving hard macros to a higher level of the hierarchical description of the design, flattening modules that are bigger than a threshold, and/or flattening star blocks. Up to three clustering strategies are employed as part of the flattening process, including name-based clustering, external connection based clustering and gate clustering.

Claims

1. A method of modifying a description of a design, comprising:

accessing said description of said design; and

modifying said description of said design to reveal data flow of said design.

2. A method according to claim 1, wherein:

said description of said design is a netlist.

3. A method according to claim 1, wherein:

said description of said design is a hierarchical description of said design; and

said performing modifications comprises moving hard macros to a higher level of said description of said design, flattening modules that are bigger than a threshold and flattening star blocks.

4. A method according to claim 1, wherein:

said description of said design is a hierarchical description of said design; and

said performing modifications comprises choosing a set of one or more modules to flatten and performing names-based clustering on said set of one or more modules to flatten.

5. A method according to claim 1, wherein:

said description of said design is a hierarchical description of said design; and

said performing modifications comprises choosing a set of one or more modules to flatten and performing external connection based clustering on said set of one or more modules to flatten.

6. A method according to claim 1, further comprising:

automatically placing hard macros in an interior region of said design; and

automatically placing other components of said design.

7. A method according to claim 1, wherein:

said description of said design is a hierarchical description of said design; and

said step of performing comprises moving hard macros to a higher level of said description of said design.

8. A method according to claim 1, wherein:

said description of said design is a hierarchical description of said design; and

said performing modifications comprises flattening modules that are bigger than a threshold.

9. A method according to claim 1, wherein:

said description of said design is a hierarchical description of said design; and

said performing modifications comprises flattening star blocks.

10. A method according to claim 9, wherein:

said star blocks include three different types of star blocks.

11. A method according to claim 1, wherein:

said description of said design is a hierarchical description of said design;

said performing modifications comprises choosing a set of one or more modules to flatten and performing clustering on said set of one or more modules to flatten; and

said clustering includes name-based clustering and external connection based clustering.

12. A method according to claim 11, wherein said choosing a set of one or more modules to flatten and performing clustering on said set of one or more modules to flatten comprises:

performing name-based clustering and external connection based clustering on modules that have hard macros and flattening said modules that have hard macros subsequent to said clustering;

performing name-based clustering and external connection based clustering on modules that are bigger than a threshold and flattening said modules that are bigger than said threshold subsequent to said clustering; and

performing name-based clustering and external connection based clustering on modules that include one or more star blocks and flattening said modules that include one or more star blocks subsequent to said clustering.

13. A method according to claim 12, wherein:

said step of performing name-based clustering and external connection based clustering on modules that have hard macros is performed in a bottom-up fashion with respect to said hierarchical description;

said step of performing name-based clustering and external connection based clustering on modules that are bigger than a threshold is performed in a top-down fashion with respect to said hierarchical description; and

said step of performing name-based clustering and external connection based clustering on modules that include one or more star blocks is performed in a top-down fashion with respect to said hierarchical description.

14. One or more processor readable storage devices having processor readable code embodied on said processor readable storage devices, said processor readable code for programming one or more processors to perform a method comprising:

accessing a description of an electrical design; and

performing modifications to said description of said electrical design to reveal data flow of said design.

15. One or more processor readable storage devices according to claim 14, wherein:

said description of said design is a netlist.

16. One or more processor readable storage devices according to claim 14, wherein:

said description of said design is a hierarchical description of said design; and

said performing modifications comprises moving hard macros to a higher level of said description of said design, flattening modules that are bigger than a threshold and flattening star blocks.

17. One or more processor readable storage devices according to claim 14, wherein:

said description of said design is a hierarchical description of said design; and

said performing modifications comprises choosing a set of one or more modules to flatten and performing names-based clustering on said set of one or more modules to flatten.

18. One or more processor readable storage devices according to claim 14, wherein:

said description of said design is a hierarchical description of said design; and

said performing modifications comprises choosing a set of one or more modules to flatten and performing external connection based clustering on said set of one or more modules to flatten.

19. One or more processor readable storage devices according to claim 14, wherein:

said description of said design is a hierarchical description of said design; and

said performing modifications comprises;

performing name-based clustering and external connection based clustering on modules that have hard macros and flattening said modules that have hard macros subsequent to said clustering,

performing name-based clustering and external connection based clustering on modules that are bigger than a threshold and flattening said modules that are bigger than said threshold subsequent to said clustering, and

performing name-based clustering and external connection based clustering on modules that include one or more star blocks and flattening said modules that include one or more star blocks subsequent to said clustering.

20. An apparatus capable of modifying a hierarchical description of a design, comprising:

one or more storage devices; and

one or more processors in communication with said one or more storage devices, said one or more processors perform a method comprising;

accessing a hierarchical description of a design stored in said one or more storage devices, and

performing modifications to said description of said design to reveal data flow of said design.

21. An apparatus according to claim 20, wherein:

said performing modifications comprises moving hard macros to a higher level of said description of said design, flattening modules that are bigger than a threshold and flattening star blocks.

22. An apparatus according to claim 20, wherein:

said performing modifications comprises choosing a set of one or more modules to flatten and performing names-based clustering on said set of one or more modules to flatten.

23. One or more processor readable storage devices according to claim 20, wherein:

said performing modifications comprises choosing a set of one or more modules to flatten and performing external connection based clustering on said set of one or more modules to flatten.

24. An apparatus according to claim 20, wherein said performing modifications comprises:

performing name-based clustering and external connection based clustering on modules that have hard macros and flattening said modules that have hard macros subsequent to said clustering;

performing name-based clustering and external connection based clustering on modules that are bigger than a threshold and flattening said modules that are bigger than said threshold subsequent to said clustering; and

performing name-based clustering and external connection based clustering on modules that include one or more star blocks and flattening said modules that include one or more star blocks subsequent to said clustering.

25. A method of modifying a hierarchical description of a design, comprising:

moving hard macros to a higher level of said hierarchical description of said design;

flattening modules that are bigger than a threshold; and

flattening star blocks.

26. A method according to claim 25, further comprising:

performing names-based clustering on modules that are to be flattened.

27. A method according to claim 25, further comprising:

performing external connection based clustering on modules that are to be flattened.

28. A method according to claim 25, further comprising:

performing names-based clustering; and

performing external connection based clustering.

29. A method according to claim 25, wherein said moving hard macros, flattening modules that are bigger than a threshold and flattening star blocks include:

performing names-based clustering; and

performing external connection based clustering.

30. A method according to claim 25, wherein:

said moving hard macros includes performing name-based clustering and external connection based clustering on modules that have hard macros and flattening said modules that have hard macros subsequent to said clustering;

said flattening modules that are bigger than a threshold includes performing name-based clustering and external connection based clustering on modules that are bigger than said threshold and flattening said modules that are bigger than said threshold subsequent to said clustering; and

said flattening star blocks includes performing name-based clustering and external connection based clustering on modules that include one or more star blocks and flattening said modules that include one or more star blocks subsequent to said clustering.

31. A method of modifying a hierarchical description of a design, comprising:

choosing a set of one or more modules to flatten; and

performing names-based clustering on said set of one or more modules to flatten.

32. A method according to claim 31, further comprising:

performing external connection based clustering on said set of one or more modules to flatten.

33. A method according to claim 31, wherein:

said choosing includes identifying star blocks.

34. A method according to claim 31, further comprising:

flattening said set of one or more modules subsequent to said performing names-based clustering.

35. A method according to claim 31, further comprising:

performing external connection based clustering on said set of one or more modules to flatten; and

flattening said set of one or more modules subsequent to said performing names-based clustering.

36. A method of modifying a hierarchical description of a design, comprising:

choosing a set of one or more modules to flatten; and

performing external connection based clustering on said set of one or more modules to flatten.

37. A method according to claim 36, wherein:

said choosing includes identifying star blocks.

38. A method according to claim 36, further comprising:

flattening said set of one or more modules subsequent to said performing external connection based clustering.

39. A method of using a hierarchical description of a design, comprising:

accessing said description of said design;

performing modifications to said description of said design;

automatically placing hard macros in an interior region of said design; and

automatically placing other components of said design.

40. A method according to claim 39, wherein said performing modifications to said description comprises:

choosing a set of one or more modules to flatten and performing names-based clustering on said set of one or more modules to flatten.

41. A method according to claim 39, wherein said performing modifications to said description comprises:

choosing a set of one or more modules to flatten and performing external connection based clustering on said set of one or more modules to flatten.

42. A method according to claim 39, wherein said performing modifications to said description comprises:

moving hard macros to a higher level of said description of said design, flattening modules that are bigger than a threshold and flattening star blocks.

43. A method according to claim 39, wherein said performing modifications to said description comprises:

identifying modules with hard macros;

performing external connection based clustering and name-based clustering on said modules with hard macros;

flattening said modules with hard macros after performing said external connection based clustering and name-based clustering on said modules with hard macros;

identifying modules that are bigger than a threshold;

performing external connection based clustering and name-based clustering on said modules that are bigger than said threshold;

flattening said modules that are bigger than said threshold after performing said external connection based clustering and name-based clustering on said modules that are bigger than said threshold;

identifying star blocks;

performing external connection based clustering and name-based clustering on said star blocks; and

flattening star blocks after performing said external connection based clustering and name-based clustering on said star blocks.