Information processing device

Information processing system including a first and a second operation mode with operating current lower than the first, a register holding an address of an instruction executed by a processing unit first when a boot address register returns from second to first operation mode, wherein the address is output to the processing unit when second to first operation mode shifting, wherein the boot address register is rewritable, an information holding circuit holding a value of a peripheral circuit module register, wherein the information holding circuit holds, in the second operation mode, information about the peripheral circuit module register, and, transfers information held in the information holding circuit to the peripheral circuit module register regarding a second-to-first operation mode shift, and wherein when an interrupt request is posted from outside the system in the second operation mode, the information processing system performs interrupt processing corresponding to the interrupt request.