The start address can be manipulated to achieve horizontal and/or vertical hardware scrolling:
*To move right: <code>start address = start address + 1</code>*To move left: <code>start address = start address - 1</code>*To move down: <code>start address = start address + R1</code>*To move up: <code>start address = start address - R1</code>
However, it is a position in word (16 bits), not in byte. So, the screen will move two bytes at a time horizontally. Also, the precision will be one CRTC character vertically.