Associative memory capable of matching a variable indicator in one string of characters with a portion of another string

摘要

An associative memory that finds the location of at least one string of characters in the associative memory that matches a string of characters presented sequentially as an input to the associative memory. The string of characters in the associative memory, the input string of characters, or both may include a specially marked characters, or set of characters, that acts as a "variable indicator." The specially marked character, or set of characters, will "match" a portion of the other string. A flag is set in the associative memory at either the starting locations or the ending locations of the matching strings. Flags are provided only at locations of stored matching strings of characters found within a selected addressable area or areas. Each flag can be moved from a first byte to a second byte in the associative memory that has a predetermined location relative to the first byte. A selection circuit selects one of the matching stored strings of characters by enabling a test signal which selects one of the flags to propagate through the associative memory circuit in a daisy-chain manner. The daisy-chain path is segmented in order to decrease the propagation time of the test signal. A summation circuit, useful in neural network applications, adds a number presented as at least one input byte to the associative memory to a number stored as at least one byte in the associative memory at the location of a stored string of characters that matches the input string.