core quality, part 2

- Bubble System WSG
- C64 (dSID)
- Game Boy
- DS
- PowerNoise

src/engine/platform/gb.cpp

@@ -70,7 +70,7 @@ void DivPlatformGB::acquire(short** buf, size_t len) {
       writes.pop();
     }
 
-    GB_advance_cycles(gb,16);
+    GB_advance_cycles(gb,coreQuality);
     buf[0][i]=gb->apu_output.final_sample.left;
     buf[1][i]=gb->apu_output.final_sample.right;
 
@@ -722,12 +722,38 @@ void DivPlatformGB::setFlags(const DivConfig& flags) {
 
   chipClock=4194304;
   CHECK_CUSTOM_CLOCK;
-  rate=chipClock/16;
+  rate=chipClock/coreQuality;
   for (int i=0; i<4; i++) {
     oscBuf[i]->rate=rate;
   }
 }
 
+void DivPlatformGB::setCoreQuality(unsigned char q) {
+  switch (q) {
+    case 0:
+      coreQuality=120;
+      break;
+    case 1:
+      coreQuality=64;
+      break;
+    case 2:
+      coreQuality=32;
+      break;
+    case 3:
+      coreQuality=16;
+      break;
+    case 4:
+      coreQuality=4;
+      break;
+    case 5:
+      coreQuality=1;
+      break;
+    default:
+      coreQuality=16;
+      break;
+  }
+}
+
 int DivPlatformGB::init(DivEngine* p, int channels, int sugRate, const DivConfig& flags) {
   parent=p;
   dumpWrites=false;