Content addressable memory address resolver
AssigneeHewlett-Packard Development Company, L.P.
InventorsVincent E. Cavanna, Mark Gooch, John A. Wickeraad
Life of this patent
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Abstract
Systems, devices, and methods, including executable instructions are provided for resolving content addressable memory (CAM) match address priority. One method includes retaining a first match address as the best match address. Subsequent match addresses are compared to the retained best match address, each match address being associated with a compare cycle during which a selected columnar portion of each CAM entry is compared to a corresponding portion of a search term. The best match address is updated as a result of the comparison.
Claims20
A method for resolving content addressable memory (CAM) match address priority, comprising:
- retaining a first match address as a best match address;
- comparing subsequent match addresses to the retained best match address;
- and
- updating the best match address as a result of the comparison;
- wherein each match address is associated with a compare cycle during which a selected columnar portion of each CAM entry is compared to a corresponding portion of a search term.
A method for resolving content addressable memory (CAM) priority, comprising:
- retaining as best match information, first match information from a first compare cycle corresponding to a first of N columns of data words in the CAM;
- receiving one at a time, new match information from a series of N compare cycles, each compare cycle corresponding to a different one of N sequentially-selected columns;
- replacing the best match information with new match information when the best match information meets a criteria selected from the group consisting of:
- includes an invalid match address, and
- includes a valid match address having a lower priority in a first dimension than a valid match address included in the new match information;
- and
- wherein columns are selected in a sequence from lowest to highest priority in a second dimension.
A content addressable memory (CAM) system, comprising:
- a CAM having multiple entries;
- a priority encoder coupled to receive match information from the CAM;
- and
- an address resolver arranged to receive match addresses pipelined from the priority encoder, and having logic configured to:
- retain a first match address as the best match address;
- compare subsequent match addresses to the retained best match address;
- and
- update the best match address as a result of the comparison;
- wherein each match address is associated with a compare cycle during which a selected columnar portion of each CAM entry is compared to a corresponding portion of a search term.
Dependencies are inferred from the claim text.