Steven Seagal wrote:ljbk wrote:I hope i have been clear enough.
You kidding, right?
Seriously, there's no 71/50 check at line cycle 376 ("position 293") in Steem for now, that could be the problem.
By the way, despite working on Steem I don't really understand ST assembly .
Ooops, sorry !
The 71/50 switch to open the right border works differently from the 60/50.
You can set $FFFF8260 to 2 at any time before a certain MMU time spot but you can not set it back to 0 before that same spot but you can set it much later.
With the 60/50 switch, you have to set the $FFFF820A to 0 a one of two time spots and then you can set it back to 2 any time after that.
For one of the 60 Hz spots, the 293, you do not need to have an EXG instuction or any instruction taking 6, 10, 14, 18, 22, ... cycles.
For the other one, either 291 in WS1 and WS3 or 295 in WS2 and WS4, you do.
You can check that some of the scan lines in the Nostalgic Demo main menu set the Right Border 60 Hz at 291 while for others it does it at 293.
For WS1 and WS3 that's fine. For WS2 and WS4, with my machine, it does not work ...
As far as i know Enchanted Land uses the 71/50 switch to open the Right Border for the sync scrolling. I do not know which time Nick selected but it works on my 1040STF Revision C.
So going back to the tests, the switchs are done at the places indicated:
-71/50 at 295/305;
-71/50 at 297/305;
-60/50 at 295/305;
and the MMU counter at $FFFF8209.w is read at the end of that line.
It can be either $CC: 204 or $A0: 160.
The combination of the three results is then tested:
WS2: CCCCCC Right Border is always open
WS1: A0A0A0 no case where Right Border was open
Better now ?