Abstract: An arithmetic apparatus for a multi-function unit and a method integrates all operations which are necessary to the GPU (graphics processing unit) with one operational device to decrease the area and power of the hardware and to control all operations except a matrix-vector multiplication to achieve a single-cycle throughput and to control a matrix-vector multiplication to achieve a 2-cycle throughput. Thus, the whole power consumption and the size and the efficiency of 3 dimensional graphics systems for the embedded systems such as the cell phone or Personal Digital Assistant can be improved as the GPU can be small-sized and advanced.