Method and apparatus for performing pattern search functions.

摘要

A method and apparatus for searching a pattern such as an address pattern of 48 bits among a list of addresses of 48 bits which can be dynamically updated. A search table (52) comprising control blocks is used for conducting the search of a specified pattern by processing logic circuits (24,26). The control blocks can be of a first type indicative of test operations on at least one selected bit of the to-be- searched pattern and of of a second type indicative of compare operations with a specified value and of a third type indicative that no operations have to be performed. These control blocks are chained in at least one chain in such a way that each control block chain determine operations which lead to the finding of one of the p patterns. To perform the search, a processing logic circuit (24 or 26) reads a first control block at a search table address which is derived from a selected field of k=12 bits of the pattern to be searched. It generates a not-found pattern signal if the read control block is of the third type, or executes the the operations indicated in the first read control block and the control blocks chained thereto, until a control block of the second type is is reached and compares the to be searched pattern with the specified value in the control block of the second type. If a mismatch is detected, it generates a "not found pattern" information and if a match is detected it generates a a "found pattern" information.