Patent ID: 6633926
Filing Date: 2003-10-14
Classification: G06F

Abstract:
A DMA transfer device that transfers data from a first region to a second region in a memory allowing high-speed page access,the DMA transfer device comprising: first detecting means for detecting a plurality of read areas that form the first region, each read area being demarcated by a page boundary and one of: (1) a start of the first region; (2) an end of the first region; and (3) another page boundary, including, first address updating means for storing an access address whose initial value is a start address of the first region and for updating the access address, whenever the access means has read all data from one read area, to a start address of a remaining part of the first region; first data size updating means for storing a remaining data size whose, initial value is a data size of the first region and for updating the remaining data size, whenever the access means has read all data from one read area, to a data size of the remaining part of the first region; and read area detecting means for detecting a read area as an area from the access address to a next page boundary when the access address is set at the initial value and for otherwise detecting a read area as an area from the access address to either a next page boundary or the end of the first region to be accessed; second detecting means for detecting a plurality of write areas that form the second region, each write area being demarcated by a page boundary and one of: (1) a start of the second region; (2) an end of the second region; and (3) another page boundary, including, second address updating means for storing an access address whose initial value is a start address of the second region and for updating the access address, whenever the access means has written all data into one write area, to a start address of a remaining part of the second region; second data size updating means for storing a remaining data size whose initial value is a data size of the second region and for updating the remaining data size, whenever the access means has written all data into one write area, to a data size of the remaining part of the second region; and write area detecting means for detecting a write area as an area from the access address in the second address updating means to a next page boundary when the access address is set at the initial value and for otherwise detecting a write area as an area from the access address to either a next page boundary or the end of the second region, including, second size detecting means for detecting a size of an area from the access address in the second address updating means to either the next page boundary or the end of the second region and second size storing means for storing the detected area size as a size of the write area, wherein the access means performs high-speed page access to the area of the write area size in the second size storing means, starting from the access address in the second address updating means; and access means for performing high-speed page access to each of the read areas and each of the write areas.