PROCESSING DEVICE, ARITHMETIC UNIT, AND CONTROL METHOD OF PROCESSING DEVICE

There is provision of a processing device including an instruction decoder and an arithmetic unit configured to process an immediate instruction for instructing a calculation of a product of an immediate value and a constant. In response to receiving the immediate instruction, the instruction decoder generates a first shift control information and a second shift control information based on the constant. The arithmetic unit generates a first shifted value by bit-shifting the immediate value received from the instruction decoder based on the first shift control information, and a second shifted value by bit-shifting the immediate value or a complement of the immediate value based on the second shift control information. By performing an addition of the first shifted value and the second shifted value, the arithmetic unit calculates the product.