PURPOSE: To improve the system performance by providing a counter at the preceding stage of an arithmetic part to set individually the code extension number, the key length, and the zero insertion number together with a means which applies the code extension and zero insertion processes to the data on the files to be processed according to the value of each counter and gives the updating control to the corresponding counter to obtain the data to be computed.
CONSTITUTION: The counters 1-3 set individually the code extension number, the key length, and the zero insertion number based on the file information given from a CPU. Then the initial count values are set to the counters 1-3 via a control bud 11, and the key data on the file to be computed is set to a data input register 5 after initialization. The data set to the register 5 is latched by an output register 7 via a selector 6 and then sent to an arithmetic part as the data to be computed. In this case, the selector 6 applies selectively the processes for extension of code,insertion of zero, etc., based on the values of the counters 1-3. As a result, the computing operations are carried out at a high speed to the files having different key lengths. Then the system performance is improved.
MATSUDA SUSUMU
TOGO KAZUO
