Thanks :) That also show how capcom fucked up this part in the megadrive conversion ;)
Here is a new version :
https://dl.dropboxusercontent.com/u/...sf2_mod_v4.bin
The latency is ok now, reduced buffer size to 32 bytes, and write buffer is only separated from read buffer by 2 segments (it was 3 as my circular buffer is 4 segments length). I cannot do any shorter latency else i will start to experience reads over write position in some case... hopefully latency is almost not perceptible now :)
I fixed a minor bug in the priority thing but it did not fixed the missing SFX bug :-/ my Z80 driver does some stuff a bit differently (as the internal counter update), maybe the 68k sound driver was using it for something after all. Also i can really heard that even if samples are far better than in the original game they are still a bit scratchy because of the early DMA. That is something i will try to fix at some point too.