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new FM frequency calculation experiments

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This commit is contained in:
tildearrow 2022-04-22 04:23:52 -05:00
parent 9c8d122389
commit 8db53faf72
4 changed files with 51 additions and 97 deletions
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78
src/engine/platform/genesis.cpp
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@ -245,15 +245,15 @@ void DivPlatformGenesis::tick(bool sysTick) {
if (chan[i].std.arp.had) {
if (!chan[i].inPorta) {
if (chan[i].std.arp.mode) {
chan[i].baseFreq=NOTE_FREQUENCY(chan[i].std.arp.val);
chan[i].baseFreq=NOTE_FNUM_BLOCK(chan[i].std.arp.val,11);
} else {
chan[i].baseFreq=NOTE_FREQUENCY(chan[i].note+(signed char)chan[i].std.arp.val);
chan[i].baseFreq=NOTE_FNUM_BLOCK(chan[i].note+(signed char)chan[i].std.arp.val,11);
}
}
chan[i].freqChanged=true;
} else {
if (chan[i].std.arp.mode && chan[i].std.arp.finished) {
chan[i].baseFreq=NOTE_FREQUENCY(chan[i].note);
chan[i].baseFreq=NOTE_FNUM_BLOCK(chan[i].note,11);
chan[i].freqChanged=true;
}
}
@ -394,9 +394,9 @@ void DivPlatformGenesis::tick(bool sysTick) {
for (int i=0; i<6; i++) {
if (i==2 && extMode) continue;
if (chan[i].freqChanged) {
chan[i].freq=parent->calcFreq(chan[i].baseFreq,chan[i].pitch,false,octave(chan[i].baseFreq));
if (chan[i].freq>262143) chan[i].freq=262143;
int freqt=toFreq(chan[i].freq)+chan[i].std.pitch.val;
chan[i].freq=((chan[i].baseFreq&0xf800)|parent->calcFreq(chan[i].baseFreq&0x7ff,chan[i].pitch,false))+chan[i].std.pitch.val;
if (chan[i].freq>65535) chan[i].freq=65535;
int freqt=chan[i].freq;
immWrite(chanOffs[i]+ADDR_FREQH,freqt>>8);
immWrite(chanOffs[i]+ADDR_FREQ,freqt&0xff);
if (chan[i].furnaceDac && dacMode) {
@ -422,47 +422,6 @@ void DivPlatformGenesis::tick(bool sysTick) {
}
}
int DivPlatformGenesis::octave(int freq) {
if (freq>=82432) {
return 128;
} else if (freq>=41216) {
return 64;
} else if (freq>=20608) {
return 32;
} else if (freq>=10304) {
return 16;
} else if (freq>=5152) {
return 8;
} else if (freq>=2576) {
return 4;
} else if (freq>=1288) {
return 2;
} else {
return 1;
}
return 1;
}
int DivPlatformGenesis::toFreq(int freq) {
if (freq>=82432) {
return 0x3800|((freq>>7)&0x7ff);
} else if (freq>=41216) {
return 0x3000|((freq>>6)&0x7ff);
} else if (freq>=20608) {
return 0x2800|((freq>>5)&0x7ff);
} else if (freq>=10304) {
return 0x2000|((freq>>4)&0x7ff);
} else if (freq>=5152) {
return 0x1800|((freq>>3)&0x7ff);
} else if (freq>=2576) {
return 0x1000|((freq>>2)&0x7ff);
} else if (freq>=1288) {
return 0x800|((freq>>1)&0x7ff);
} else {
return freq&0x7ff;
}
}
void DivPlatformGenesis::muteChannel(int ch, bool mute) {
isMuted[ch]=mute;
for (int j=0; j<4; j++) {
@ -509,7 +468,7 @@ int DivPlatformGenesis::dispatch(DivCommand c) {
dacPos=0;
dacPeriod=0;
if (c.value!=DIV_NOTE_NULL) {
chan[c.chan].baseFreq=NOTE_FREQUENCY(c.value);
chan[c.chan].baseFreq=NOTE_FNUM_BLOCK(c.value,11);
chan[c.chan].freqChanged=true;
}
chan[c.chan].furnaceDac=true;
@ -576,7 +535,7 @@ int DivPlatformGenesis::dispatch(DivCommand c) {
chan[c.chan].insChanged=false;
if (c.value!=DIV_NOTE_NULL) {
chan[c.chan].baseFreq=NOTE_FREQUENCY(c.value);
chan[c.chan].baseFreq=NOTE_FNUM_BLOCK(c.value,11);
chan[c.chan].portaPause=false;
chan[c.chan].note=c.value;
chan[c.chan].freqChanged=true;
@ -656,26 +615,33 @@ int DivPlatformGenesis::dispatch(DivCommand c) {
break;
}
case DIV_CMD_NOTE_PORTA: {
int destFreq=NOTE_FREQUENCY(c.value2);
int destFreq=NOTE_FNUM_BLOCK(c.value2,11);
int newFreq;
bool return2=false;
if (destFreq>chan[c.chan].baseFreq) {
newFreq=chan[c.chan].baseFreq+c.value*octave(chan[c.chan].baseFreq);
newFreq=chan[c.chan].baseFreq+c.value;
if (newFreq>=destFreq) {
newFreq=destFreq;
return2=true;
}
} else {
newFreq=chan[c.chan].baseFreq-c.value*octave(chan[c.chan].baseFreq);
newFreq=chan[c.chan].baseFreq-c.value;
if (newFreq<=destFreq) {
newFreq=destFreq;
return2=true;
}
}
// check for octave boundary
if (!chan[c.chan].portaPause) {
if (octave(chan[c.chan].baseFreq)!=octave(newFreq)) {
chan[c.chan].portaPause=true;
break;
if ((newFreq&0x7ff)>1288) {
newFreq=((newFreq&0x7ff)>>1)|((newFreq+0x800)&0xf800);
/*chan[c.chan].portaPause=true;
break;*/
}
if ((newFreq&0x7ff)<644) {
newFreq=(newFreq&0x7ff)<<1|((newFreq-0x800)&0xf800);
/*chan[c.chan].portaPause=true;
break;*/
}
}
chan[c.chan].baseFreq=newFreq;
@ -699,7 +665,7 @@ int DivPlatformGenesis::dispatch(DivCommand c) {
}
break;
case DIV_CMD_LEGATO: {
chan[c.chan].baseFreq=NOTE_FREQUENCY(c.value);
chan[c.chan].baseFreq=NOTE_FNUM_BLOCK(c.value,11);
chan[c.chan].note=c.value;
chan[c.chan].freqChanged=true;
break;