Posted By
bubis
on 2019-08-19
19:48:10
|  Re: Alpharay Plus/4 just released at Evoke 2019
Hi,
Mad: Thanks for the technical details, awesome!
As for the HSP routine: Please don't ask me to explain how it works, because I don't fully understand yet. I am sure that there are some inner registers and states in TED what we don't see in the $FFxx area and some $FF1E values trigger some events like pointer incrementing start, pointer incrementing stop and pointer reload (there are things like that mentioned in some TED tech doc without explanation) and I am messing with these events by setting $FF1E to the right values at the right cycles.
Yes, I experimented a LOT! At the begining I only had stable routines for some shift values, but those also ruined the PAL signal. First, I fixed those to work properly. Then, I tried to extend them many ways to work with close values and looked for a pattern what I can generalize. I managed to do 0-37 with one routine using two $FF1E writes, but that didn't work for 38 and 39. It turned out I need a third $FF1E write, a part of the final routine deals with only those cases.
And of couse, the final routine is the result of a lots of polishing.
I will publish this code later this week or next week. I ask for a little patience!
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