PURPOSE: To enhance the processing function without increasing the order function for the information processor which processes the information based on the order word, by carrying out the process independent from the order shown the order word when the information is the prescribed one.

CONSTITUTION: The order word composed of the arithmetic indication code and the immediate IM data code is drawn into instruction decoder 10 and IM field 11 from bus 16. Gate circit part 14 is provided between buses 18 and 19 which connect field 11 to logic arithmetic part 12, and the data in place of the IM data is supplied to part 14 from data input source 15 via bus 20. The control is given via control line 23 from decoder 10 to decide whether the input to ALU12 should be substituted by the IM data given from the IM field or the data given from data source 15. The IM data of accumulator 13 holding the addition data or the data from data source 15 is supplied to ALU12 and then calculated, and this arithmetic result is held at accumulator 13.