APU square issue about fceux

[dragon2snow]

try cpu ram fill ff

[bbbradsmith]

That doesn't appear to affect it, @dragon2snow.

[dragon2snow]

oh，

[eugene-s-nesdev]

FCEUX 2.2.2 (with no RAM init option) and even FCEUltra 0.98.12 (Aug-28-2004) has this bug:
R.C. Pro-Am II (U) [FCEUX].zip

http://wiki.nesdev.com/w/index.php/APU_Sweep
If i understand correctly, when sweep unit is muting the channel, the current period should remain unchanged. Removing curfreq[P]=0; fixes this without causing square-channel related issues to a few common titles i have tested.

diff --git a/src/sound.cpp b/src/sound.cpp
index 7390cce8..7acd4273 100644
--- a/src/sound.cpp
+++ b/src/sound.cpp
@@ -443,7 +443,7 @@ static void FrameSoundStuff(int V)
       if((mod+curfreq[P])&0x800)
       {
        sweepon[P]=0;
-       curfreq[P]=0;
+       //curfreq[P]=0;
       }
       else
       {

[g0me3]

looks legit, let's try it and reopen the issue if someone prove this is wrong...