MEMORY WRITING DEVICE AND ITS WRITING METHOD

PROBLEM TO BE SOLVED: To solve problems that much time is required for writing data in a memory when writing data from a DMA device is larger than a data bus width in conventional constitution though more acceleration of system operation is required and the acceleration of system operation is disabled especially when misalign memory writing occurs because writing efficiency is extremely deteriorated. SOLUTION: The memory writing device is provided with a DMA device 103 for collectively outputting written data at more than the device bus width of a CPU 100 and requesting a DMA, a DMA controller 102 for collectively inputting the written data at more than the data bus width of the CPU 100 from the DMA device 103, inputting the number of writing bytes, generating a mask write signal for mask writing, and successively writing data in a DIMM 101 by the data width of the CPU 100 and the DIMM 101 having a mask writing function.