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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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66
src/engine/platform/genesisext.cpp
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@ -72,7 +72,7 @@ int DivPlatformGenesisExt::dispatch(DivCommand c) {
opChan[ch].insChanged=false;
if (c.value!=DIV_NOTE_NULL) {
opChan[ch].baseFreq=NOTE_FREQUENCY(c.value);
opChan[ch].baseFreq=NOTE_FNUM_BLOCK(c.value,11);
opChan[ch].portaPause=false;
opChan[ch].freqChanged=true;
}
@ -127,31 +127,46 @@ int DivPlatformGenesisExt::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>opChan[ch].baseFreq) {
newFreq=opChan[ch].baseFreq+c.value*octave(opChan[ch].baseFreq);
newFreq=opChan[ch].baseFreq+c.value;
if (newFreq>=destFreq) {
newFreq=destFreq;
return2=true;
}
} else {
newFreq=opChan[ch].baseFreq-c.value*octave(opChan[ch].baseFreq);
newFreq=opChan[ch].baseFreq-c.value;
if (newFreq<=destFreq) {
newFreq=destFreq;
return2=true;
}
}
if (!opChan[ch].portaPause) {
if (octave(opChan[ch].baseFreq)!=octave(newFreq)) {
opChan[ch].freqChanged=true;
if ((newFreq&0x7ff)>1288) {
newFreq=((newFreq&0x7ff)>>1)|((newFreq+0x800)&0xf800);
opChan[ch].portaPause=true;
break;
opChan[ch].freqChanged=false;
return2=false;
if (ch==3) printf("%d: upper bound\n",ch);
//break;
}
if ((newFreq&0x7ff)<644) {
newFreq=(newFreq&0x7ff)<<1|((newFreq-0x800)&0xf800);
opChan[ch].portaPause=true;
opChan[ch].freqChanged=false;
return2=false;
if (ch==3) printf("%d: lower bound\n",ch);
//break;
}
} else {
opChan[ch].portaPause=false;
opChan[ch].freqChanged=true;
}
if (ch==3) printf("%d: writing %.4x to freq\n",ch,newFreq);
opChan[ch].baseFreq=newFreq;
opChan[ch].portaPause=false;
opChan[ch].freqChanged=true;
if (return2) return 2;
break;
}
@ -172,7 +187,7 @@ int DivPlatformGenesisExt::dispatch(DivCommand c) {
}
break;
case DIV_CMD_LEGATO: {
opChan[ch].baseFreq=NOTE_FREQUENCY(c.value);
opChan[ch].baseFreq=NOTE_FNUM_BLOCK(c.value,11);
opChan[ch].freqChanged=true;
break;
}
@ -289,35 +304,10 @@ void DivPlatformGenesisExt::tick(bool sysTick) {
unsigned char writeMask=2;
if (extMode) for (int i=0; i<4; i++) {
if (opChan[i].freqChanged) {
opChan[i].freq=parent->calcFreq(opChan[i].baseFreq,opChan[i].pitch);
if (opChan[i].freq>262143) opChan[i].freq=262143;
if (opChan[i].freq>=82432) {
opChan[i].freqH=((opChan[i].freq>>15)&7)|0x38;
opChan[i].freqL=(opChan[i].freq>>7)&0xff;
} else if (opChan[i].freq>=41216) {
opChan[i].freqH=((opChan[i].freq>>14)&7)|0x30;
opChan[i].freqL=(opChan[i].freq>>6)&0xff;
} else if (opChan[i].freq>=20608) {
opChan[i].freqH=((opChan[i].freq>>13)&7)|0x28;
opChan[i].freqL=(opChan[i].freq>>5)&0xff;
} else if (opChan[i].freq>=10304) {
opChan[i].freqH=((opChan[i].freq>>12)&7)|0x20;
opChan[i].freqL=(opChan[i].freq>>4)&0xff;
} else if (opChan[i].freq>=5152) {
opChan[i].freqH=((opChan[i].freq>>11)&7)|0x18;
opChan[i].freqL=(opChan[i].freq>>3)&0xff;
} else if (opChan[i].freq>=2576) {
opChan[i].freqH=((opChan[i].freq>>10)&7)|0x10;
opChan[i].freqL=(opChan[i].freq>>2)&0xff;
} else if (opChan[i].freq>=1288) {
opChan[i].freqH=((opChan[i].freq>>9)&7)|0x08;
opChan[i].freqL=(opChan[i].freq>>1)&0xff;
} else {
opChan[i].freqH=(opChan[i].freq>>8)&7;
opChan[i].freqL=opChan[i].freq&0xff;
}
immWrite(opChanOffsH[i],opChan[i].freqH);
immWrite(opChanOffsL[i],opChan[i].freqL);
opChan[i].freq=(opChan[i].baseFreq&0xf800)|parent->calcFreq(opChan[i].baseFreq&0x7ff,opChan[i].pitch);
if (chan[i].freq>65535) chan[i].freq=65535;
immWrite(opChanOffsH[i],opChan[i].freq>>8);
immWrite(opChanOffsL[i],opChan[i].freq&0xff);
}
writeMask|=opChan[i].active<<(4+i);
if (opChan[i].keyOn) {