Patent ID: 6742087
Filing Date: 2004-05-25
Classification: G06F

Abstract:
A method of controlling access to a memory device commonly shared by a plurality of data processing units, said memory device including 2M memory units (M being a natural number) which are independently controllable and have the same data bus width as said data processing units, comprising:assigning addresses to each of said memory units such that addresses in each of said memory units changes in the same manner as other memory units and corresponding addresses in said data processing unit vary in accordance with arrangement of said memory units in said memory device; when one of said data processing units requests to read data in said memory device at a data size which is 2k times said data bus width (1&lE;k&lE;M and k being a natural number), reading said data from the corresponding 2k memory units at the same time; and independently supplying data from each of said corresponding 2k memory units to said one of said data processing units; when said one of said data processing units requests to read desired data at a desired address from one of said memory units at a data size which is 2P times said data width (0&lE;p&lE;Mâˆ’1 and p being a natural number), and if no other data processing unit requests access to said memory device, reading said desired data and, at the same time, reading other data from another memory unit other than said one of said memory units at an address following said desired address; storing said other data in a temporary register as pre-loading data; and supplying said other data from said temporary register to said one of said data processing units after supplying said desired data to said one of said data processing units when said one of said data processing units requests to read said other data at said address following said desired address, wherein when said desired data is other than an instruction for executing a predetermined process in said one of said data processing units, inhibiting reading of said another data.