FDS FM values exported incorrectly to NSF

[galap-1]

I mentioned this earlier in the discord, and have done some investigation and found out more about the problem.

When the automatic FM effect produces a modulation rate over the maximum amount i.e. greater than $4806 = $FF and &4807 = $0F, in 0cc they just get set to $FF and $0F respectively, but when exporting an NSF, some strange behavior ensues. This does not happen when manually setting them to $FF and $0F with I0F JFF.

Upon importing the nsf file using NSFimport and looking at the register values, they are an incorrect, lower valuse. It appears that it is overflowing and wrapping around.

fds bug.zip

[nyanpasu64]

sorry for not replying

i'm not actively working on j0cc at the moment, and probably will not fix it soon. is there any real musical value for FM at such a high frequency?

if you can figure it out, throw me a pull request. i'll leave the issue open.

[galap-1]

That's alright. I can do almost everything I want to by manually using I0F JFF.

Very high frequency FM is very useful to me for creating a tube amp overdrive effect (when used in combination with some other techniques). I don't know if anyone else has used it in this manner though.