C64: finish it all

all modules play correctly, bar:
- motherfunksignal (almost)
- filters are a bit weird

src/engine/platform/c64.h

@@ -7,10 +7,11 @@
 
 class DivPlatformC64: public DivDispatch {
   struct Channel {
-    int freq, baseFreq, pitch, prevFreq, testWhen;
-    unsigned char ins, note, sweep, wave;
+    int freq, baseFreq, pitch, prevFreq, testWhen, note;
+    unsigned char ins, sweep, wave, attack, decay, sustain, release;
     short duty;
-    bool active, insChanged, freqChanged, sweepChanged, keyOn, keyOff, inPorta;
+    bool active, insChanged, freqChanged, sweepChanged, keyOn, keyOff, inPorta, filter;
+    bool resetMask, resetFilter, resetDuty, ring, sync;
     signed char vol, outVol;
     DivMacroInt std;
     Channel():
@@ -19,10 +20,14 @@ class DivPlatformC64: public DivDispatch {
       pitch(0),
       prevFreq(65535),
       testWhen(0),
-      ins(-1),
       note(0),
+      ins(-1),
       sweep(0),
       wave(0),
+      attack(0),
+      decay(0),
+      sustain(0),
+      release(0),
       duty(0),
       active(false),
       insChanged(true),
@@ -31,13 +36,22 @@ class DivPlatformC64: public DivDispatch {
       keyOn(false),
       keyOff(false),
       inPorta(false),
+      filter(false),
+      resetMask(false),
+      resetFilter(false),
+      resetDuty(false),
+      ring(false),
+      sync(false),
       vol(15) {}
   };
   Channel chan[3];
 
+  unsigned char filtControl, filtRes, vol;
+  int filtCut, resetTime;
+
   SID sid;
 
-  void updateWave();
+  void updateFilter();
   public:
     void acquire(short* bufL, short* bufR, size_t start, size_t len);
     int dispatch(DivCommand c);