| 摘要 |
PURPOSE:To process image data quickly by simultaneously reading and writing drawing data corresponding to plural picture elements. CONSTITUTION:A describing command from a CPU is inputted to a functional controller 20 through a CPU interface. The controller 20 analyzes the command to generate VRAM data (description data) for write on a VRAM display area and records this data in a color register having the storage capacity corresponding to four picture elements. A converting part 20 is provided with a description data register 54, a rewrite logic 53, and a VRAM data register 55. VRAM data from the color register is supplied to the register 53 and is converted by the logic 53 for the purpose of making specific color data transparent and is written on the VRAM from the register 55 through a VRAM interface 16. At this time, color data corresponding to four picture elements in the horizontal direction is read or written simultaneously between the VRAM and the color register.
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