Electrical computers and digital processing systems: memory – Storage accessing and control – Specific memory composition
Reissue Patent
2002-10-31
2009-10-06
Elmore, Reba I (Department: 2189)
Electrical computers and digital processing systems: memory
Storage accessing and control
Specific memory composition
C711S100000, C711S103000
Reissue Patent
active
RE040932
ABSTRACT:
A CAM system is provided for determining which data word in a CAM array exhibits the longest continuous, unmasked match with an input data value. The input data value is divided into non-overlapping subfields, thereby creating a series of keys, the first key of the series including either the least significant bit (LSB) or most significant bit (MSB) of the input data value. The CAM array is divided along columns into a similar series of non-overlapping sub-arrays corresponding to the subfields defined by the series of keys. A first CAM sub-array compares the first key with its stored rows of data bit values to generate a first match signal. The first match signal disables each row of the second CAM sub-array for which the corresponding row of the first CAM sub-array did not show a match. A second CAM sub-array then compares the second key with its enabled rows to generate a second match signal. The second match signal disables each row of the third CAM sub-array for which the corresponding row of either the first or second CAM sub-array did not show a match. This comparison process continues in sequence with the remaining keys and CAM sub-arrays. The row of the CAM array that shows a match over the most consecutive comparison operations contains the longest match for the input data value. If multiple rows match over the same number of comparison operations, a priority encoder determines which location has the highest priority.
REFERENCES:
patent: 6191969 (2001-02-01), Pereira
patent: 6191970 (2001-02-01), Pereira
patent: 6219748 (2001-04-01), Srinivasan et al.
patent: 6237061 (2001-05-01), Srinivasan et al.
patent: 6240485 (2001-05-01), Srinivasan et al.
patent: 6243280 (2001-06-01), Wong et al.
patent: 6243281 (2001-06-01), Pereira
patent: 6246601 (2001-06-01), Pereira
patent: 6252789 (2001-06-01), Pereira et al.
patent: 6324087 (2001-11-01), Pereira
patent: 6430074 (2002-08-01), Srinivasan
patent: 6499081 (2002-12-01), Nataraj et al.
patent: 6552920 (2003-04-01), Chadwick et al.
patent: 6760242 (2004-07-01), Park et al.
Diede Thomas
Mick John R.
Elmore Reba I
Mahamedi Paradice Kreisman LLC
NetLogic Microsystems, Inc.
LandOfFree
Content addressable memory (CAM) devices that perform... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Content addressable memory (CAM) devices that perform..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Content addressable memory (CAM) devices that perform... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-4106383