SNES: fix possible sample corruption

when toggling echo

src/engine/platform/opll.cpp

@@ -392,6 +392,15 @@ void DivPlatformOPLL::commitState(int ch, DivInstrument* ins) {
   }
 }
 
+void DivPlatformOPLL::switchMode(bool mode) {
+  if (mode==properDrums) return;
+  if (mode) {
+
+  } else {
+
+  }
+}
+
 int DivPlatformOPLL::dispatch(DivCommand c) {
   switch (c.cmd) {
     case DIV_CMD_NOTE_ON: {

src/engine/platform/opll.h

@@ -75,6 +75,7 @@ class DivPlatformOPLL: public DivDispatch {
     int octave(int freq);
     int toFreq(int freq);
     void commitState(int ch, DivInstrument* ins);
+    void switchMode(bool mode);
 
     friend void putDispatchChip(void*,int);
     friend void putDispatchChan(void*,int,int);

src/engine/platform/snes.cpp

@@ -733,6 +733,7 @@ int DivPlatformSNES::getRegisterPoolSize() {
 
 void DivPlatformSNES::initEcho() {
   unsigned char esa=0xf8-(echoDelay<<3);
+  unsigned char control=(noiseFreq&0x1f)|(echoOn?0:0x20);
   if (echoOn) {
     rWrite(0x6d,esa);
     rWrite(0x7d,echoDelay);
@@ -742,13 +743,14 @@ void DivPlatformSNES::initEcho() {
     for (int i=0; i<8; i++) {
       rWrite(0x0f+(i<<4),echoFIR[i]);
     }
+    rWrite(0x6c,control);
   } else {
-    rWrite(0x6d,0);
-    rWrite(0x7d,0);
     rWrite(0x2c,0);
     rWrite(0x3c,0);
+    rWrite(0x6c,control);
+    rWrite(0x7d,0);
+    rWrite(0x6d,0xff);
   }
-  writeControl=true;
 }
 
 void DivPlatformSNES::reset() {