US5281558A
Expired / Lapsed
US
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Cloning method and system for hierarchical compaction
Assignee: Cadence Design Systems Inc
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Filing: 1992-11-02
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Granted: 1994-01-25
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Expires: 2012-11-02
Abstract
Abstract A computer system and computer-implemented method for compacting the geometrical area of a hierarchical integrated circuit layout. The present invention is particularly adapted for use with layouts including over-the-cell routing (OTCR). The inventive method includes the general steps of normalizing the cells, compacting the cells, then reconstructing the layout that includes the normalized cells. More particularly, the step of normalizing the cells includes initial step of identifying an overlapping object produced from the OTCR that overlaps one of the instances. That overlapping object is then divided into an overlapping segment and a non-overlapping segment. The overlapping segment is then removed from the cell and copied into the leaf cell of the overlapped instance. The overlapping segment is defined as a special object of the cell into which it is copied.
Inventors
- 👤 Cyrus S. Bamji
- 👤 Ravi Varadarajan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 05:03
CPC Classifications
G; G06; G06F; G06F30/00; G06F30/30; G06F30/39; G06F30/398
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
124 words
A computer-implemented method for compacting the geometrical area of a hierarchical integrated circuit layout, the layout including instances, cells, objects, and utilizing over-the-cell routing, the method comprising the sequential steps of: A. normalizing the cells, including the normalizing substeps of: (a) identifying an overlapping object, produced from the over-the-cell routing, that overlaps one of the instances; (b) dividing the overlapping object into an overlapping segment that overlaps the instance and a non-overlapping segment that is outside of the instance; (c) removing the overlapping segment from the cell; and (d) copying the overlapping segment into the cell of the overlapped instance, the overlapping segment being defined as a special object of the cell; B. compacting cells with special objects; and then C. reconstructing the layout.
Claim 2
Dependent Claim
124 words
A computer-implemented method for compacting the geometrical area of a hierarchical integrated circuit layout, the layout including instances, cells, objects, and utilizing over-the-cell routing, the method comprising the sequential steps of: A. normalizing the cells, including the normalizing substeps of: (a) identifying an overlapping object, produced from the over-the-cell routing, that overlaps one of the instances; (b) dividing the overlapping object into an overlapping segment that overlaps the instance and a non-overlapping segment that is outside of the instance; (c) removing the overlapping segment from the cell; and (d) copying the overlapping segment into the cell of the overlapped instance, the overlapping segment being defined as a special object of the cell; B. compacting cells with special objects; and then C. reconstructing the layout.
Claim 3
Dependent Claim
33 words
The method of claim 1 further comprising the step of generating a clone tag associated with the special object, the clone tag including a list of instance identifications associated with the special object.
Claim 4
Dependent Claim
22 words
The method of claim 2 further comprising the step of, after normalizing substep (d), defining a relationship between pairs of the objects.
Claim 5
Dependent Claim
74 words
The method of claim 3 wherein a first clone tag Tag1 is associated with a first object and a second clone tag Tag2 is associated with a second object, the first object and the second object defining tagged objects, and wherein the relationship defining step further comprises identifying one relationship from the group of relationships including same clone tag, Tag1 is a subset of Tag2, Tag2 is a subset of Tag1, and no relationship.
Claim 6
Dependent Claim
31 words
The method of claim 4 wherein the compacting step further comprises the steps of: performing net extraction using the tagged objects; and then creating a graph representative of the net extraction.
Claim 7
Dependent Claim
22 words
The method of claim 5 wherein the compacting step further comprises generating correct design rule constraints by querying the net extraction graph.
Claim 8
Dependent Claim
31 words
The method of claim 1 wherein the normalizing substeps (a) through (d) are performed top down through the hierarchical layout until each of the cells includes only objects and special objects.
Claim 9
Dependent Claim
33 words
The method of claim 7 further comprising the step of generating a clone tag associated with the special object, the clone tag including a list of instance identifications associated with the special object.
Claim 10
Dependent Claim
22 words
The method of claim 8 further comprising the step of, after normalizing substep (d), defining a relationship between pairs of the objects.
Claim 11
Dependent Claim
74 words
The method of claim 9 wherein a first clone tag Tag1 is associated with a first object and a second clone tag Tag2 is associated with a second object, the first object and the second object defining tagged objects, and wherein the relationship defining step further comprises identifying one relationship from the group of relationships including same clone tag, Tag1 is a subset of Tag2, Tag2 is a subset of Tag1, and no relationship.
Claim 12
Dependent Claim
31 words
The method of claim 10 wherein the compacting step further comprises the steps of: performing net extraction using the tagged objects; and then creating a graph representative of the net extraction.
Claim 13
Dependent Claim
22 words
The method of claim 11 wherein the compacting step further comprises generating correct design rule constraints by querying the net extraction graph.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-01-24 | 1997-07-26 | 1998-01-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-01-24 | 2001-07-26 | 2002-01-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-01-24 | 2005-07-26 | 2006-01-25 | $7700.00 | Window Closed / Lapsed |