On Thu, 3 Jun 2004, Richard Smith wrote:
This will only skip the jump (and do the BX decrement) if ax is zero. For ax to be zero the result of the 2's complement subtraction must be zero or the when the 2 reads are the same number. But I just don't see how this would happen repeatably at .6us per ISA IO.
All I know is BIOS code sucks and it looks like VGA BIOS code is worse than BIOS code. IT's amazing that any of it ever worked at all.
ron