🚀 go-pugleaf

joe@proto.com (Joe Huffman) writes:

>bpz4r@holmes.acc.Virginia.EDU (Bernard Paul Ziegler) writes:

>>I'm looking for help on how to directly write to the VGA's palette
>>registers, in order to do quick color scrolling.  Using the BIOS
>>functions is too slow.  Does anyone know of some references for this?
>>I have a paradise VGA card.

Actually, the hard part here is getting the screen updates to sync with 
the damn register writes so you don't get a flickering black band
across the middle of your screen... I tried to write a simple one
a while ago, and biffed some of the palette rotation machine code
from Fractint source - it ran pretty poorly, since i'm no assembly
coder.  Does anybody have some good stand-alone source or object
code that can be used with MSC 600 which rotates the palette quickly?
I know the basics of the palette registers, so i'm more interested in
the timing. From looking at the Fractint code, it seemed that after every
write to the registers, they checked on the status of the screen update,
and if it was incomplete, they cut the size of the block updated at once
into smaller blocks - change a block, wait for update, change next block,
etc., until all registers are updated. Is this an accurate guess? Or 
are non-bios functions fast enough to not worry about this?

nye