Electrical computers and digital processing systems: memory – Storage accessing and control – Specific memory composition
Reexamination Certificate
2000-06-14
2004-06-15
Bataille, Pierre-Michel (Department: 2186)
Electrical computers and digital processing systems: memory
Storage accessing and control
Specific memory composition
C365S049130, C365S230030
Reexamination Certificate
active
06751701
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to content addressable memories (CAMs), and more particularly to intra-row configurability of a CAM array.
BACKGROUND
A content addressable memory (CAM) system is a storage system that can be instructed to compare a specific pattern of comparand data with data stored in its associative CAM array. The entire CAM array, or segments thereof, is searched in parallel for a match with the comparand data. The CAM device typically includes a priority encoder to translate the highest priority matching location into a match address or CAM index.
The CAM array has rows of CAM cells that each store a number of bits of a data word. U.S. Pat. No. 5,440,715 describes a technique for expanding the width of the data words beyond that of a single row of CAM cells. This inter-row configurability provides flexibility in the use of the single CAM array to store data words larger than that available in a single addressable row of CAM cells.
It would be desirable to have a CAM system that includes intra-row configurability to provide additional flexibility in the use of a single CAM array to be used in multiple array configurations. Intra-row configurability is the ability to access and operate upon one or more segments of rows of CAM cells.
SUMMARY OF THE INVENTION
A method and apparatus for detecting a multiple match in an intra-row configurable CAM system is disclosed. For one embodiment, the CAM system includes a CAM array and multiple match flag logic. The CAM system has a plurality of rows of CAM cells each row segmented into a plurality of row segments having a plurality of CAM cells coupled to a corresponding match line segment. The multiple match flag logic is coupled to the match line segments and determines when first comparand data matches data stored in each of two or more row segments in response to first configuration information, and determines when second comparand data matches data stored in each of two or more groups of row segments in response to second configuration information. The first configuration information is indicative of a first width and depth configuration of the CAM array, and the second configuration information is indicative of a second width and depth configuration of the CAM array.
REFERENCES:
patent: 3257646 (1966-06-01), Roth
patent: 3353159 (1967-11-01), Lee, III
patent: 3602899 (1971-08-01), Lindquist et al.
patent: 3675211 (1972-07-01), Raviv
patent: 4159538 (1979-06-01), Motsch
patent: 4244033 (1981-01-01), Hattori
patent: 4575818 (1986-03-01), Almy et al.
patent: 4622653 (1986-11-01), McElroy
patent: 4656626 (1987-04-01), Yudichak et al.
patent: 4670858 (1987-06-01), Almy
patent: 4813002 (1989-03-01), Joyce et al.
patent: 4845668 (1989-07-01), Sano et al.
patent: 4928260 (1990-05-01), Chuang et al.
patent: 4958377 (1990-09-01), Takahashi
patent: 4996666 (1991-02-01), Duluk, Jr.
patent: 5053991 (1991-10-01), Burrows
patent: 5072422 (1991-12-01), Rachels
patent: 5123105 (1992-06-01), Wyland et al.
patent: 5319589 (1994-06-01), Yamagata et al.
patent: 5325501 (1994-06-01), Carlstedt
patent: 5383146 (1995-01-01), Threewitt
patent: 5394353 (1995-02-01), Nusinov et al.
patent: 5440715 (1995-08-01), Wyland
patent: 5444649 (1995-08-01), Nemirovsky
patent: 5448733 (1995-09-01), Satoh et al.
patent: 5483480 (1996-01-01), Yoneda
patent: 5485418 (1996-01-01), Hiraki et al.
patent: 5555397 (1996-09-01), Sasama et al.
patent: 5576985 (1996-11-01), Holtz
patent: 5642322 (1997-06-01), Yoneda
patent: 5649149 (1997-07-01), Stormon et al.
patent: 5706224 (1998-01-01), Srinivasan et al.
patent: 5717901 (1998-02-01), Sung et al.
patent: 5787458 (1998-07-01), Miwa
patent: 5818786 (1998-10-01), Yoneda
patent: 5860085 (1999-01-01), Stormon et al.
patent: 5870324 (1999-02-01), Helwig et al.
patent: 5920886 (1999-07-01), Feldmeier
patent: 5930790 (1999-07-01), Law et al.
patent: 5943252 (1999-08-01), Schultz et al.
patent: 5946704 (1999-08-01), Yoneda et al.
patent: 5999435 (1999-12-01), Henderson et al.
patent: 6000008 (1999-12-01), Simcoe
patent: 6006306 (1999-12-01), Haywood et al.
patent: 6011795 (2000-01-01), Varghese et al.
patent: 6044005 (2000-03-01), Gibson et al.
patent: 6081440 (2000-06-01), Washburn et al.
patent: 6081441 (2000-06-01), Ikeda
patent: 6081442 (2000-06-01), Igarashi et al.
patent: 6098147 (2000-08-01), Mizuhara
patent: 6122702 (2000-09-01), Pelagalli et al.
patent: 6144574 (2000-11-01), Kobayashi et al.
patent: 6147890 (2000-11-01), Kawana et al.
patent: 6161144 (2000-12-01), Michels et al.
patent: 6166938 (2000-12-01), Wong
patent: 6175514 (2001-01-01), Henderson et al.
patent: 6181698 (2001-01-01), Hariguchi
patent: 6237061 (2001-05-01), Srinivasan et al.
patent: 6240000 (2001-05-01), Sywyk et al.
patent: 6243281 (2001-06-01), Pereira
patent: 6253280 (2001-06-01), Voelkel
patent: 6266262 (2001-07-01), Washburn et al.
patent: 6289414 (2001-09-01), Feldmeier et al.
patent: 6310880 (2001-10-01), Waller
patent: 6370613 (2002-04-01), Diede et al.
patent: 0774758 (1997-05-01), None
patent: 0858077 (1998-08-01), None
patent: 0622805 (1999-07-01), None
patent: 0918335 (1999-08-01), None
patent: 08273376 (1996-01-01), None
patent: 11-102589 (1999-04-01), None
patent: WO99/23663 (1999-05-01), None
Ken Schultz and Andrew Sorowka, “High Performance CAMs for 10GB/s and Beyond”, Gigabit Ethernet Conference (GEC2000), Mar. 27, 2000, pp. 147-154.
PCT International Search Report for PCT Int'l Appln No. US01/40954, mailed Feb. 6, 2002 (7 pages).
Bataille Pierre-Michel
Netlogic Microsystems Inc.
LandOfFree
Method and apparatus for detecting a multiple match in an... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for detecting a multiple match in an..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for detecting a multiple match in an... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3351874