Image Number 15 for United States Patent #5448733.
This is a variable length data search apparatus which uses a latch, added to each word of a cell array. In this apparatus, the search operation is self controlled by using the previous matching signals stored in the latches. A character string (ABCA), from a data string (BABCABB . . . ), is stored, in order, in an associative memory containing, e.g., six rows having addresses 1 to 6, and the first character of the data string is sent to a buffer and a comparison is made. This sequence is repeated for each character but now the comparison is made only at the cell rows addresses which are adjacent the cell rows, which matched the previous character. This means that even if the length of the search character string is a variable length, only the number of times the comparison operation is repeated varies and this permits the search to be completed in an extremely short time as compared to the prior art. A data compression circuit based on the LZ1 algorithm is also disclosed and uses; a data input control circuit, the variable length search apparatus disclosed above; a write address controller, and address register; a garbage address controller; a matching length counter and a compressed data output circuit.