C64: better muting strategy

now directly inside reSID rather than in the DivDispatch
fixes #285

src/engine/platform/c64.cpp

@@ -168,16 +168,16 @@ void DivPlatformC64::tick() {
     }
     if (chan[i].testWhen>0) {
       if (--chan[i].testWhen<1) {
-        if (!chan[i].resetMask && !isMuted[i]) {
+        if (!chan[i].resetMask) {
           rWrite(i*7+5,0);
           rWrite(i*7+6,0);
-          rWrite(i*7+4,(isMuted[i]?8:(chan[i].wave<<4))|8|(chan[i].ring<<2)|(chan[i].sync<<1));
+          rWrite(i*7+4,(chan[i].wave<<4)|8|(chan[i].ring<<2)|(chan[i].sync<<1));
         }
       }
     }
     if (chan[i].std.wave.had) {
       chan[i].wave=chan[i].std.wave.val;
-      rWrite(i*7+4,(isMuted[i]?8:(chan[i].wave<<4))|(chan[i].ring<<2)|(chan[i].sync<<1)|(int)(chan[i].active));
+      rWrite(i*7+4,(chan[i].wave<<4)|(chan[i].ring<<2)|(chan[i].sync<<1)|(int)(chan[i].active));
     }
     if (chan[i].std.ex1.had) {
       filtControl=chan[i].std.ex1.val&15;
@@ -199,12 +199,12 @@ void DivPlatformC64::tick() {
       if (chan[i].keyOn) {
         rWrite(i*7+5,(chan[i].attack<<4)|(chan[i].decay));
         rWrite(i*7+6,(chan[i].sustain<<4)|(chan[i].release));
-        rWrite(i*7+4,(isMuted[i]?8:(chan[i].wave<<4))|(chan[i].ring<<2)|(chan[i].sync<<1)|1);
+        rWrite(i*7+4,(chan[i].wave<<4)|(chan[i].ring<<2)|(chan[i].sync<<1)|1);
       }
-      if (chan[i].keyOff && !isMuted[i]) {
+      if (chan[i].keyOff) {
         rWrite(i*7+5,(chan[i].attack<<4)|(chan[i].decay));
         rWrite(i*7+6,(chan[i].sustain<<4)|(chan[i].release));
-        rWrite(i*7+4,(isMuted[i]?8:(chan[i].wave<<4))|(chan[i].ring<<2)|(chan[i].sync<<1)|0);
+        rWrite(i*7+4,(chan[i].wave<<4)|(chan[i].ring<<2)|(chan[i].sync<<1)|0);
       }
       rWrite(i*7,chan[i].freq&0xff);
       rWrite(i*7+1,chan[i].freq>>8);
@@ -330,7 +330,7 @@ int DivPlatformC64::dispatch(DivCommand c) {
       break;
     case DIV_CMD_WAVE:
       chan[c.chan].wave=c.value;
-      rWrite(c.chan*7+4,(isMuted[c.chan]?8:(chan[c.chan].wave<<4))|(chan[c.chan].ring<<2)|(chan[c.chan].sync<<1)|(int)(chan[c.chan].active));
+      rWrite(c.chan*7+4,(chan[c.chan].wave<<4)|(chan[c.chan].ring<<2)|(chan[c.chan].sync<<1)|(int)(chan[c.chan].active));
       break;
     case DIV_CMD_LEGATO:
       chan[c.chan].baseFreq=NOTE_FREQUENCY(c.value+((chan[c.chan].std.arp.will && !chan[c.chan].std.arp.mode)?(chan[c.chan].std.arp.val):(0)));
@@ -411,11 +411,11 @@ int DivPlatformC64::dispatch(DivCommand c) {
           break;
         case 4:
           chan[c.chan].ring=c.value;
-          rWrite(c.chan*7+4,(isMuted[c.chan]?8:(chan[c.chan].wave<<4))|(chan[c.chan].ring<<2)|(chan[c.chan].sync<<1)|(int)(chan[c.chan].active));
+          rWrite(c.chan*7+4,(chan[c.chan].wave<<4)|(chan[c.chan].ring<<2)|(chan[c.chan].sync<<1)|(int)(chan[c.chan].active));
           break;
         case 5:
           chan[c.chan].sync=c.value;
-          rWrite(c.chan*7+4,(isMuted[c.chan]?8:(chan[c.chan].wave<<4))|(chan[c.chan].ring<<2)|(chan[c.chan].sync<<1)|(int)(chan[c.chan].active));
+          rWrite(c.chan*7+4,(chan[c.chan].wave<<4)|(chan[c.chan].ring<<2)|(chan[c.chan].sync<<1)|(int)(chan[c.chan].active));
           break;
         case 6:
           filtControl&=7;
@@ -434,7 +434,7 @@ int DivPlatformC64::dispatch(DivCommand c) {
 
 void DivPlatformC64::muteChannel(int ch, bool mute) {
   isMuted[ch]=mute;
-  rWrite(ch*7+4,(isMuted[ch]?8:(chan[ch].wave<<4))|(chan[ch].ring<<2)|(chan[ch].sync<<1)|(int)(chan[ch].active));
+  sid.set_is_muted(ch,mute);
 }
 
 void DivPlatformC64::forceIns() {
@@ -475,6 +475,10 @@ int DivPlatformC64::getRegisterPoolSize() {
   return 32;
 }
 
+bool DivPlatformC64::getDCOffRequired() {
+  return true;
+}
+
 void DivPlatformC64::reset() {
   for (int i=0; i<3; i++) {
     chan[i]=DivPlatformC64::Channel();

src/engine/platform/c64.h

@@ -87,6 +87,7 @@ class DivPlatformC64: public DivDispatch {
     void muteChannel(int ch, bool mute);
     void setFlags(unsigned int flags);
     void notifyInsChange(int ins);
+    bool getDCOffRequired();
     void notifyInsDeletion(void* ins);
     void poke(unsigned int addr, unsigned short val);
     void poke(std::vector<DivRegWrite>& wlist);

src/engine/platform/sound/c64/sid.cc

@@ -18,6 +18,7 @@
 //  ---------------------------------------------------------------------------
 
 #include "sid.h"
+#include <stdio.h>
 #include <math.h>
 
 // ----------------------------------------------------------------------------
@@ -39,6 +40,10 @@ SID::SID()
   bus_value_ttl = 0;
 
   ext_in = 0;
+
+  isMuted[0]=false;
+  isMuted[1]=false;
+  isMuted[2]=false;
 }
 
 
@@ -51,6 +56,14 @@ SID::~SID()
   delete[] fir;
 }
 
+// ----------------------------------------------------------------------------
+// Mute/unmute channel.
+// ----------------------------------------------------------------------------
+void SID::set_is_muted(int ch, bool val) {
+  if (ch<0 || ch>2) return;
+  isMuted[ch]=val;
+}
+
 
 // ----------------------------------------------------------------------------
 // Set chip model.
@@ -626,7 +639,7 @@ void SID::clock()
   }
 
   // Clock filter.
-  filter.clock(voice[0].output(), voice[1].output(), voice[2].output(), ext_in);
+  filter.clock(isMuted[0]?0:voice[0].output(), isMuted[1]?0:voice[1].output(), isMuted[2]?0:voice[2].output(), ext_in);
 
   // Clock external filter.
   extfilt.clock(filter.output());
@@ -706,7 +719,7 @@ void SID::clock(cycle_count delta_t)
 
   // Clock filter.
   filter.clock(delta_t,
-	       voice[0].output(), voice[1].output(), voice[2].output(), ext_in);
+	       isMuted[0]?0:voice[0].output(), isMuted[1]?0:voice[1].output(), isMuted[2]?0:voice[2].output(), ext_in);
 
   // Clock external filter.
   extfilt.clock(delta_t, filter.output());

src/engine/platform/sound/c64/sid.h

@@ -32,6 +32,7 @@ public:
   SID();
   ~SID();
 
+  void set_is_muted(int ch, bool val);
   void set_chip_model(chip_model model);
   void enable_filter(bool enable);
   void enable_external_filter(bool enable);
@@ -102,6 +103,8 @@ protected:
   Potentiometer potx;
   Potentiometer poty;
 
+  bool isMuted[3];
+
   reg8 bus_value;
   cycle_count bus_value_ttl;