Method and system for implementing core placement

• US 8,549,457 B1
• Filed: 08/26/2011
• Issued: 10/01/2013
• Est. Priority Date: 08/26/2011
• Status: Expired due to Fees

• Current Assignee: Cadence Design Systems Incorporated (Cadence Group)
• Original Assignee: Cadence Design Systems Incorporated (Cadence Group)
• Inventors: Moore, Timothy P., McCracken, Thaddeus C.
• Primary Examiner(s): Siek, Vuthe
• Assistant Examiner(s): Alam, Mohammed
• Application Number:
  US13/219,553
• Time in Patent Office: 767 Days
• Field of Search: 716/119, 716/123
• US Class Current: 716/123
• CPC Class Codes: G06F 2113/18 Chip packaging
• CPC Class Codes: G06F 30/392 Floor-planning or layout, e.g. partitioning or placement

Abstract

Disclosed is an improved method, system, and computer program product for performing core placement when presented with an I/O ring design. A multi-pass approach is taken to place and shape core objects into the available core area formed by the inner surface of the I/O ring. The multi-pass approach permits very fast placement of the core objects, which still provides for an accurate estimation of the die size and configuration requirements for the electronic design. Moreover, the present approach allows core objects to be placed in a way that retains any preferred affinities for the objects to be located near other objects, e.g., near specific I/Os on the I/O ring.

Claims

1. A computer-implemented method implemented with a processor for performing core placement for an electronic product, comprising:

using at least one processor to perform a process, the process comprising;

performing a first pass placement of at least some of core objects into a core area, where

the core area is surrounded by an I/O ring that includes one or more pin structures, and

the first pass placement corresponds to at least one limiting condition for placing the core objects; and

performing a second pass placement for one or more remaining core objects of the core objects, in which the second pass placement permits complex shape placement for the one or more remaining core objects of the core objects.

2. The method of claim 1 in which the least one limiting condition for placing the core objects in the first pass placement comprises a limiting threshold number of attempts to place an object.

3. The method of claim 1 in which the least one limiting condition for placing the core objects in the first pass placement comprises a prohibition on placing a non-rectilinear shape.

4. The method of claim 1 in which molding is performed to create more contiguous free space in the core area.

5. The method of claim 1 in which a B* tree approach is employed to place the core objects.

6. The method of claim 1 further comprising performing preliminary placement of the core objects.

7. The method of claim 6 in which the preliminary placement is performed for objects having location or proximity preferences.

8. The method of claim 1 in which the core objects are sorted for placement.

9. The method of claim 1 further comprising recursive placement for different hierarchical levels of design elements in the electronic product.

10. The method of claim 1 in which the core objects may be subject to aspect ratio changes for placement.

11. The method of claim 1 further comprising:

performing a third pass placement in which the third pass placement permits shape overlaps for the core objects.

12. A computer program product embodied on a non-transitory computer usable medium, the non-transitory computer readable medium having stored thereon a sequence of instructions which, when executed by a processor causes the processor to execute a method performing core placement for an electronic product, the method comprising:

performing a first pass placement of at least some of core objects into a core area, where

the core area is surrounded by an I/O ring that includes one or more pin structures, and

the first pass placement corresponds to at least one limiting condition for placing the core objects; and

performing a second pass placement for one or more remaining core objects of the core objects, in which the second pass placement permits complex shape placement for the one or more remaining core objects of the core objects.

13. The computer program product of claim 12 in which the least one limiting condition for placing the core objects in the first pass placement comprises a limiting threshold number of attempts to place an object.

14. The computer program product of claim 12 in which the least one limiting condition for placing the core objects in the first pass placement comprises a prohibition on placing a non-rectilinear shape.

15. The computer program product of claim 12 in which molding is performed to create more contiguous free space in the core area.

16. The computer program product of claim 12 in which a B* tree approach is employed to place the core objects.

17. The computer program product of claim 12 further comprising performing preliminary placement of the core objects.

18. The computer program product of claim 17 in which the preliminary placement is performed for objects having location or proximity preferences.

19. The computer program product of claim 12 in which the core objects are sorted for placement.

20. The computer program product of claim 12 further comprising recursive placement for different hierarchical levels of design elements in the electronic product.

21. The computer program product of claim 12 in which the core objects may be subject to aspect ratio changes for placement.

22. The computer program product of claim 12 further comprising:

performing a third pass placement in which the third pass placement permits shape overlaps for the core objects.

23. A system for performing core placement for an electronic product, comprising:

a processor;

a memory for holding programmable code, wherein

the programmable code includes instructions which, when executed by the processor, cause the processor to;

perform a first pass placement of at least some of core objects into a core area, where

the core area is surrounded by an I/O ring that includes one or more pin structures in an I/O area, and

the first pass placement corresponds to at least one limiting condition for placing the core objects; and

perform a second pass placement for one or more remaining core objects of the core objects, in which the second pass placement permits complex shape placement for the one or more remaining core objects of the core objects.

24. The system of claim 23 in which the least one limiting condition for placing the core objects in the first pass placement comprises a limiting threshold number of attempts to place an object.

25. The system of claim 23 in which the least one limiting condition for placing the core objects in the first pass placement comprises a prohibition on placing a non-rectilinear shape.

26. The system of claim 23 in which molding is performed to create more contiguous free space in the core area.

27. The system of claim 23 in which a B* tree approach is employed to place the core objects.

28. The system of claim 23 further comprising performing preliminary placement of the core objects.

29. The system of claim 28 in which the preliminary placement is performed for objects having location or proximity preferences.

30. The system of claim 23 in which the core objects are sorted for placement.

31. The system of claim 23 in which recursive placement is implemented for different hierarchical levels of design elements in the electronic product.

32. The system of claim 23 in which the core objects may be subject to aspect ratio changes for placement.

33. The system of claim 23 in which the programmable code includes instructions for performing a third pass placement in which the third pass placement permits shape overlaps for the core objects.