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US 8,788,791 B2Granted
Low power, hash-content addressable memory architecture
AssigneeMicron Technology, Inc.
InventorKeith R. Slavin
Life of this patent
Estimating the term…
Abstract
A comparand word is input to a plurality of hash circuits with each hash circuit responding to a different portion of the comparand word. The hash circuit outputs a hash signal which enables or pre-charges portions of a content addressable memory (CAM). The comparand word is also input to the CAM. The CAM compares the comparand word in the pre-charged portions of the CAM and outputs information responsive to the comparison. When Internet addresses are processed, the output information may be port information or an index for locating.
Claims21
An apparatus, comprising:
- a content addressable memory;
- a plurality of hash circuits each configured to produce a respective hash signal responsive to a prefix of a comparand word for prefix lengths greater than n-bits;
- a memory configured to produce a hash signal responsive to the prefix of the comparand word for prefix lengths n-bits or less;
- and
- enable logic configured to receive the hash signals from the plurality of hash circuits and the memory and further configured to enable portions of the content addressable memory based on the hash signals, the enabled portions of the content addressable memory to be compared with the comparand word.
2 more elements
A method, comprising:
- providing an input word to a plurality of hash circuits, each hash circuit configured for a different respective prefix length;
- outputting a hash signal from each hash circuit;
- enabling portions of a CAM in response to the hash signals;
- providing the input word to the CAM;
- comparing the input word to the enabled portions of the CAM;
- and
- outputting information responsive to the comparing.
4 more elements
A method, comprising:
- mapping destinations to ports;
- hashing network addresses;
- loading hash values and address prefixes into a hash table;
- linking routing addresses and port information to said hash values;
- loading information from the hash table into a CAM;
- and
- writing hole values in the CAM.
4 more elements
Dependencies are inferred from the claim text.