| 摘要 |
PURPOSE:To increase the speed of data write to a VRAM. CONSTITUTION:When raster operation is not performed, the non-operation mode where raster operation is not executed is detected by a decoder 127, and then, the operation of a raster operation circuit 121 is disabled, and the input on the side of a system bus interface 123 is selected by a multiplexer 125. Therefore, write data from the system bus interface 123 is directly supplied to a memory control circuit 14 without passing a bus size conversion circuit 122 neither the raster operation circuit 121. Consequently, the division processing to segment the write data by 8 bits is unnecessary to increase the speed of write of 32-bit write data from the system to a VRAM 30. |
