1. A region descriptor management method, adapted to a device controller of an electronic apparatus, the management method comprising: fetching a plurality of region descriptor entries from a region descriptor table, wherein each of the plurality of region descriptor entries comprises a block initial address and a block length to correspondingly describe a memory block of a memory module; according to the block initial addresses and the block lengths of the plurality of region descriptor entries, adjusting a portion of the plurality of region descriptor entries to be at least one current region descriptor entry; and based on the at least one current region descriptor entry, generating a current region descriptor table.