Reading or writing while searching in a CAM

Abstract

The present invention provides a content addressable memory (CAM) match search circuit that permits searching of the search circuit while accessing for reading from, writing to, or refreshing a match detection circuit within the search circuit. In accordance with an exemplary embodiment of the invention, rather than allowing the allowing the search circuit to search a match detection circuit being accessed, the match detection circuit is isolated and forced to indicate a mismatch. Furthermore, the contents of the match detection circuit are stored separately and subsequently searched.

1 . A method of operating a content addressable memory (CAM), the method comprising: 
 accessing a selected storage location of said CAM for a memory operation;    disabling a match detection circuit associated with said selected storage location during said access operation;    searching other storage locations of said CAM during said access operation by comparing the data stored in each of respective other storage locations to a stored word using respective enabled match detection circuits associated with said other storage locations;    accessing data from said selected storage location;    comparing said accessed data to said stored word in a comparing circuit separate from said disabled match detection circuit; and 
 comparing the data stored in each said respective other sotrage locations to a stored word.  
   
   
   
       2 - 99 . (canceled)