PURPOSE: To enable high-speed drawing on a graphic memory by omitting two processes of reading a pattern out of a main memory and generating drawing data by a CPU.

CONSTITUTION: The display control circuit is equipped with a destination register 2 which reads optional destination data out of the graphic memory 1, a source register 4 which reads the drawing data out of the main memory 3, a pattern memory 5 stored with pattern data, a data generating circuit 7 which generates destination data after rewriting from the three data, and a pattern pointer register 6 stored with position data on a reference pattern. Then a repetitive pattern for the background of the destination data is composed.