| 摘要 |
PROBLEM TO BE SOLVED: To prevent new data capacity from being required when exchanging data stored in a memory. SOLUTION: A BitBLT engine is provided with a swap control part 15. While transferring image data read out of the first and second data areas of a memory 3 to read FIFO 4A and 4B, the data quantities of the read FIFO 4A and 4B are monitored and when the data quantities of the read FIFO 4A and 4B reach a prescribed quantity, the image data in the first and second areas are selectively transferred to a write FIFO 5 and written in the memory 3 by a switch circuit 16 for storing the image data in the read FIFO 4A in the second area and storing the image data in the read FIFO 4B in the first area. Thus, data in two data areas can be exchanged without using a new data area. COPYRIGHT: (C)2003,JPO
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