An apparatus comprises a circuitry, a temporary memory and a permanent memory storing necessary information for executing each of a plurality types of processing. The apparatus receives a switching instruction and switches processing executed by the circuitry by varying the necessary information in response to reception of the instruction. The information is read out and loaded into a first region of the temporary memory. If the circuitry is executing at least one of the plurality types of processing when the instruction is made, the apparatus switches the circuitry to a state of being capable of executing the processing by reading out the information of the processing, loading the information into a second region of the temporary memory, and moving or copying the information related to the processing from the second region to the first region in response to the executing processing ending.