INFORMATION PROCESSING DEVICE AND DMA TRANSFER METHOD

摘要

PROBLEM TO BE SOLVED: To dispense with monitoring of the number of transferred sections of data by a CPU in DMA transfer while dividing the data for reducing the load on the CPU. SOLUTION: A system control part prepares descriptor information (step S1). A plurality of pieces of descriptor information are formed in accordance with the respective sections of image data so that the image data on a single sheet of image are divided into a plurality of sections for inputting/outputting the image data to/from an image memory through DMA transfer independently of the CPU in the system control part. Each descriptor information includes an instruction bit instructing an action to be carried out by an input/output DMA controller in advance of a start of DMA transfer based on the following descriptor information after DMA transfer based on the descriptor information is finished. The input/output DMA controller sequentially carries out a plurality of pieces of descriptor information for performing operation according to the instruction bit in every DMA transfer of a single section of the image data.