[DPMHHacker]

Hello guys: I have a problem:

How does Horizontal & Vertical Scrolling on the Genesis work? All I know is that there is a VSRAM and a Horizontal Scroll data or something that controls scrolling and that the VDP Registers can also help you change the horizontal and Vertical Scroll type. So:
First question: What does the bits in the data mean, like what do the first second third...etc... bit do for Horizontal scroll data and vertical scroll data?
Second Question: are you able to change the scroll data during HBlank or something like that?
Thank You!!!