DSP Library is a software library that implements numeric operation function used in Digital Signal processor with general purpose MCU. Software library is suitable when using general purpose MCU and desiring to add DSP features other than conventional system control function. In addition to the functionality of general purpose MCU, Renesas MCU supports DSP function instructions with a focus on multiplication and accumulation functions. We offer a high performance software library that is able to realize the DSP function without having to know the details of these instructions.