Patent ID: 6897873

Claim:
A display control apparatus comprising: a video memory for storing color data, which are used to designate colors for displayed dots, palette data for use in conversion of the color data and address data representing addresses of the color data and the palette data; a first video memory controller for reading the palette data from the video memory in accordance with the address data, so that read palette data are written to a color palette memory; a second video memory controller for reading the color data from the video memory in accordance with the address data, so that read color data are subjected to conversion on the color palette memory in accordance with the palette data; and an output circuit for outputting either the color data read from the video memory or converted color data output from the color palette memory to a display, wherein at completion of writing the previous palette data to the color palette memory, the first video memory controller retains the previous address data designating the previous palette data in a register, the first video memory controller determines whether to replace content of the color palette memory by comparison between the present address data and the previous address data such that if present address data designating present palette data matches with previous address data designating previous palette data, the first video memory controller does not write the present palette data to the color palette memory.