Allow enabling and disabling operators, closes #111

Thanks @rsta2

src/dexedadapter.h

@@ -25,6 +25,8 @@
 #include <circle/spinlock.h>
 #include <stdint.h>
 
+#define DEXED_OP_ENABLE (DEXED_OP_OSC_DETUNE + 1)
+
 // Some Dexed methods require to be guarded from being interrupted
 // by other Dexed calls. This is done herein.
 

src/minidexed.cpp

@@ -68,6 +68,7 @@ CMiniDexed::CMiniDexed (CConfig *pConfig, CInterruptSystem *pInterrupt,
 		m_nNoteShift[i] = 0;
 
 		m_nReverbSend[i] = 0;
+		m_uchOPMask[i] = 0b111111;	// All operators on
 
 		m_pTG[i] = new CDexedAdapter (CConfig::MaxNotes, pConfig->GetSampleRate ());
 		assert (m_pTG[i]);
@@ -682,7 +683,14 @@ void CMiniDexed::SetVoiceParameter (uint8_t uchOffset, uint8_t uchValue, unsigne
 	uchOffset += nOP * 21;
 	assert (uchOffset < 156);
 
-	m_pTG[nTG]->setVoiceDataElement (uchOffset, uchValue);
+	if (nOP < 6 && uchOffset == DEXED_OP_ENABLE)
+	{
+		// https://github.com/probonopd/MiniDexed/issues/111#issuecomment-1103319499
+		m_pTG[nTG]->setVoiceDataElement (uchOffset, uchValue);
+		m_pTG[nTG]->setOPAll(m_uchOPMask[nTG]);
+	} else {
+		m_pTG[nTG]->setVoiceDataElement (uchOffset, uchValue);
+	}
 }
 
 uint8_t CMiniDexed::GetVoiceParameter (uint8_t uchOffset, unsigned nOP, unsigned nTG)
@@ -699,7 +707,15 @@ uint8_t CMiniDexed::GetVoiceParameter (uint8_t uchOffset, unsigned nOP, unsigned
 	uchOffset += nOP * 21;
 	assert (uchOffset < 156);
 
-	return m_pTG[nTG]->getVoiceDataElement (uchOffset);
+	if (nOP < 6 && uchOffset == DEXED_OP_ENABLE)
+	{
+		// https://github.com/probonopd/MiniDexed/issues/111#issuecomment-1103319499
+		// In this case the bit for the respective operator
+		// in m_uchOPMask[] must be returned (0 or 1)
+		return 1 == ( (m_pTG[nTG]->getVoiceDataElement (uchOffset) >> nTG) & 1);
+	} else {
+		return m_pTG[nTG]->getVoiceDataElement (uchOffset);
+	}
 }
 
 std::string CMiniDexed::GetVoiceName (unsigned nTG)

src/minidexed.h

@@ -81,7 +81,8 @@ public:
 	void ControllersRefresh (unsigned nTG);
 
 	void SetReverbSend (unsigned nReverbSend, unsigned nTG);			// 0 .. 127
-
+	uint8_t m_uchOPMask[CConfig::ToneGenerators];
+	
 	enum TParameter
 	{
 		ParameterCompressorEnable,

src/uimenu.cpp

@@ -151,6 +151,7 @@ const CUIMenu::TMenuItem CUIMenu::s_OperatorMenu[] =
 	{"Rate Scaling",EditOPParameter,	0,	DEXED_OP_OSC_RATE_SCALE},
 	{"A Mod Sens.",	EditOPParameter,	0,	DEXED_OP_AMP_MOD_SENS},
 	{"K Vel. Sens.",EditOPParameter,	0,	DEXED_OP_KEY_VEL_SENS},
+	{"Enable", EditOPParameter, 0, DEXED_OP_ENABLE},
 	{0}
 };
 
@@ -234,7 +235,8 @@ const CUIMenu::TParameter CUIMenu::s_OPParameter[] =
 	{0,	1,	1,	ToOscillatorMode},	// DEXED_OP_OSC_MODE
 	{0,	31,	1},				// DEXED_OP_FREQ_COARSE
 	{0,	99,	1},				// DEXED_OP_FREQ_FINE
-	{0,	14,	1,	ToOscillatorDetune}	// DEXED_OP_OSC_DETUNE
+	{0,	14,	1,	ToOscillatorDetune},	// DEXED_OP_OSC_DETUNE
+	{0, 1, 1, ToOnOff}		// DEXED_OP_ENABLE
 };
 
 const char CUIMenu::s_NoteName[100][4] =