Content addressable memory with block-programmable mask write mode, word width and priority

A method of operation within a content addressable memory (CAM) device that includes a plurality of CAM blocks, the method comprising:

• selecting a subset of the CAM blocks according to a class code;
• comparing a comparand value to data words stored in the selected subset of CAM blocks to identify matching data words;
• and
• generating an index according to priority values stored in the selected subset of CAM blocks and associated with the matching data words.

A system comprising:

• a processor;
• and
• a CAM device coupled to the processor, the CAM device including:
• a plurality of CAM blocks, each CAM block having an array of CAM cells to store data words and an array of priority number storage circuits to store priority numbers, each priority number indicating a priority of a respective one of the data words relative to others of the data words;
• and
• a block control circuit having an input to receive a class code and circuitry to output a plurality of select signals to the plurality of CAM blocks, each select signal to selectively disable a respective one of the plurality of CAM blocks from participating in a compare operation according to the class code.