To make a data string processible in a normal ascending order with a small number of variables and a small number of instructions.
A full length len of a processing object is calculated by the product of a processing unit length LB of data and the number Nu of pieces of processing data (S2), the front pointer sp of a processing object area and the len are added to be a processing reference pointer sp (S3), the front pointer dp of a storage area and the len are added to be a storage reference pointer dp (S4), -len is used as a variable LV (S5), data is subsequently read by instructing by sp+LV and is supplied to a CPU (S6), the CPU processes the data (S7), the results are stored in a memory by instructing with dp+LV (S8), LV is updated by LV←LV+LB (S9), and steps S6 to S9 are repeated during LV<0.