Patent ID: 8179398

Claim:
A screen display control device comprising: a compression unit which compresses input image data into line units of compressed data; a rewritable image memory to which line units of compressed data compressed by the compression unit are written in non-synchronization with a reading process; a decompression unit which decompresses line units of compressed data periodically read from the image memory in synchronization with screen display during the reading process to restore original image data; a display unit which displays an image of original image data decompressed and restored by the decompression unit; a buffer memory which temporarily maintains compressed one-line data compressed by the compression unit; and a writing/reading control unit which controls writing compressed data to the image memory, reading compressed data from the image memory, writing compressed data to the buffer memory, and reading compressed data from the buffer memory, wherein, when writing a first line unit of compressed data corresponding to a particular line to the image memory competes with reading a second line unit or compressed data corresponding to the same particular line from the image memory, the writing/reading control unit writes the first line unit of compressed data to the buffer memory, and wherein the writing/reading control unit reads the first line unit of compressed data from the buffer memory when the reading process subsequently requires a line unit of compressed data corresponding to the particular line to be read.