PURPOSE: To shorten the execution time for an information processing by providing an extension instructing latch for discriminating an extending method for an operand which is designated from an instruction decoding part.

CONSTITUTION: A data matching detecting device 5 consisting of a deciding circuit 13 for deciding whether an operation output becomes zero extension or code extension data or not from the contents of an extension instructing latch 3 and a result of detection by a line 25 of a detecting circuit 12 and inputting selectively a result of decision to a flag selecting means 14 by a line 41 is added to the title processor. In this state, a determined output is informed to the flag selecting means 14 by the control line 41, and one bit can be set to a flag register 15 through a line 39 by a control of a control storage 7. In such a way, the conformability of data can be detected by a common processing without being conscious of word length of an operand and an extending method for the operand by the control storage 7.