| 摘要 |
PURPOSE:To execute smearing by storing address information to a stock area without disabling drawing even when a stack memory storing the address information at boundary end points in an internal area of a graphics drawing overflows. CONSTITUTION:A DDA 1 executes drawing by executing instruction from a processing unit 5. When the processing unit 5 gives an indication of smearing of the graphics drawing, line smearing is applied and then the boundary end points of the internal area of the graphics drawing are detected by checking points under and above the said line. The address information at the boundary end points is sent to the stack memory 4 and stored. When the stack memory 4 overflows, the DDA 1 detects it to start a DMA control circuit 7 and the address information as to the boundary end points detected further is transferred to a stack area 61 in a main storage device 6. When all boundary end points are detected and stored, the DMA control circuit 7 reads the address information from the stack area 61 and when it is completed, the address information is read from the stack memory 4 to execute smearing. |
