DRAM ADDRESS MAPPING CIRCUIT WITH DMAC FOR MULTI-CPU CORE PROCESSOR

摘要

PROBLEM TO BE SOLVED: To solve the problem that when a CPU core or an OS is 32 bit in a CPU system (PC, Tablet PC, PDA or the like), a main storage size is limited to about 3.5 GB which is equal to or less than 4 GB, and a memory loaded with a size of more than 4 GB (3.5 GB) becomes useless in a present state, and that since a current RAMDISK which is effective for execution speed improvement uses the main storage, the limitation of the main storage size is a hindrance to performance improvement in a 32 bit system.;SOLUTION: A circuit for mapping a local address of a DRAM to a system physical address includes a DMA function so that it is possible to economically use a DRAM area which has not been allocated to a main storage as a RAMDISK, and data transfer relating to this is locally performed on a local bus of the DRAM so that it is possible to supply the RAMDISK which is more excellent in execution efficiency than the RAMDISK using a conventional main storage.;COPYRIGHT: (C)2013,JPO&INPIT