| 摘要 |
PURPOSE: To simplify the circuit constitution and to increase the data processing speed by returning forcedly the boundary color to a CPU as data for the access that is given from the CPU beyond the plotting area of a video memory. CONSTITUTION: The data stored in the plotting area 35 of a video memory 18 are successively read out toward the higher order addresses from the lower order ones. If a graphic plotted in a 1st code (a) partly swells out the area 35, the code (a) showing the termination of a paint-out range is not stored in the memory 18. However, the code (a) received from a 1st code output means 2 not the data (c) given from the memory 18 is sent to a CPU 11 via an output data selection means 3 when a plotting area decision means 1 decides that the scanning is done out of the area 35. When the input of the code (a) is decided, the CPU 11 decides the termination of the paint-out range and the paint-out operation done by a 2nd code (b) is finished on a relevant scanning line. |
