| 摘要 |
<p>PURPOSE:To provide a CRT controller capable of highspeed scrolling in an optional direction without necessity of moving a displayed image into a block by a software for preventing the passing of the range of a block area at the time of a scrolling in a Y direction. CONSTITUTION:This controller is provided with a CPU 1 for outputting the display control command of the CRT, a GC 2 for controlling plotting and display on a VRAM 3 via a conversion circuit 6 by the instruction of the CPU 1, the VRAM 3 with addresses alotted to respective area blocks so as to provide the image address space of the same-sized area whose addresses are serial next to the area block for scrolling and the conversion circuit 6 for converting an image address value nonexistent in the VRAM 3 outputted by the CG 2 into an existent address value.</p> |
