Abstract: A digital circuit for executing an arithmetic operation includes an overflow processing capability. The overflow processing is performed by a shifter to correct a decimal point. The shifter is used to shift a result of the arithmetic operation with an overflow and to shift a data to be operated by an arithmetic unit. The result and the data are applied to the shifter via a multiplexer, and either one of them is transferred to the shifter. The shifter is controlled such that the result of the arithmetic operation is shifted by one bit, while the data is shifted according to the number of overflows. As the result, the digital circuit can perform an arithmetic operation at a high speed by means of a simple hardware element.