furnace/src/engine/platform/tia.cpp

#include "tia.h"
#include "../engine.h"
#include <string.h>
#include <math.h>

#define rWrite(a,v) if (!skipRegisterWrites) {tia.set(a,v);}

void DivPlatformTIA::acquire(short* bufL, short* bufR, size_t start, size_t len) {
  tia.process(bufL+start,len);
}

unsigned char dealWithFreq(unsigned char shape, int base, int pitch) {
  if (base&0x80000000 && ((base&0x7fffffff)<32)) {
    return base&0x1f;
  }
  int bp=base+pitch;
  double mult=0.25*27.5*pow(2.0,double(768+bp)/(256.0*12.0));
  switch (shape) {
    case 1: // buzzy
      return ceil(31400/(30.6*mult))-1;
      break;
    case 2: // low buzzy
      return ceil(31400/(480*mult))-1;
      break;
    case 3: // flangy
      return ceil(31400/(60*mult))-1;
      break;
    case 4: case 5: // square
      return ceil(31400/(4.05*mult))-1;
      break;
    case 6: case 7: case 8: case 9: case 10: // pure buzzy/reedy/noise
      return ceil(31400/(63*mult))-1;
      break;
    case 12: case 13: // low square
      return round(31400/(4.0*3*mult))-1;
      break;
    case 14: case 15: // low pure buzzy/reedy
      return ceil(31400/(3*63*mult))-1;
      break;
  }
  return 0;
}

void DivPlatformTIA::tick() {
  for (int i=0; i<2; i++) {
    chan[i].std.next();
    if (chan[i].std.hadVol) {
      chan[i].outVol=chan[i].std.vol-(15-chan[i].vol);
      if (chan[i].outVol<0) chan[i].outVol=0;
      if (isMuted[i]) {
        rWrite(0x19+i,0);
      } else {
        rWrite(0x19+i,chan[i].outVol&15);
      }
    }
    if (chan[i].std.hadArp) {
      if (!chan[i].inPorta) {
        if (chan[i].std.arpMode) {
          chan[i].baseFreq=0x80000000|chan[i].std.arp;
        } else {
          chan[i].baseFreq=(chan[i].note+chan[i].std.arp-12)<<8;
        }
      }
      chan[i].freqChanged=true;
    } else {
      if (chan[i].std.arpMode && chan[i].std.finishedArp) {
        chan[i].baseFreq=chan[i].note<<8;
        chan[i].freqChanged=true;
      }
    }
    if (chan[i].std.hadWave) {
      chan[i].shape=chan[i].std.wave&15;
      rWrite(0x15+i,chan[i].shape);
      chan[i].freqChanged=true;
    }
    if (chan[i].freqChanged || chan[i].keyOn || chan[i].keyOff) {
      if (chan[i].insChanged) {
        if (!chan[i].std.willWave) {
          chan[i].shape=4;
          rWrite(0x15+i,chan[i].shape);
        }
        chan[i].insChanged=false;
      }
      chan[i].freq=dealWithFreq(chan[i].shape,chan[i].baseFreq,chan[i].pitch);
      if ((chan[i].shape==4 || chan[i].shape==5) && !(chan[i].baseFreq&0x80000000 && ((chan[i].baseFreq&0x7fffffff)<32))) {
        if (chan[i].baseFreq<39*256) {
          rWrite(0x15+i,6);
          chan[i].freq=dealWithFreq(6,chan[i].baseFreq,chan[i].pitch);
        } else if (chan[i].baseFreq<59*256) {
          rWrite(0x15+i,12);
          chan[i].freq=dealWithFreq(12,chan[i].baseFreq,chan[i].pitch);
        } else {
          rWrite(0x15+i,chan[i].shape);
        }
      }
      if (chan[i].freq>31) chan[i].freq=31;
      if (chan[i].keyOff) {
        rWrite(0x19+i,0);
      }
      rWrite(0x17+i,chan[i].freq);
      if (chan[i].keyOn) chan[i].keyOn=false;
      if (chan[i].keyOff) chan[i].keyOff=false;
      chan[i].freqChanged=false;
    }
  }
}

int DivPlatformTIA::dispatch(DivCommand c) {
  switch (c.cmd) {
    case DIV_CMD_NOTE_ON: {
      DivInstrument* ins=parent->getIns(chan[c.chan].ins);
      chan[c.chan].baseFreq=c.value<<8;
      chan[c.chan].freqChanged=true;
      chan[c.chan].note=c.value;
      chan[c.chan].active=true;
      chan[c.chan].keyOn=true;
      rWrite(0x15+c.chan,chan[c.chan].shape);
      chan[c.chan].std.init(ins);
      if (isMuted[c.chan]) {
        rWrite(0x19+c.chan,0);
      } else {
        rWrite(0x19+c.chan,chan[c.chan].vol&15);
      }
      break;
    }
    case DIV_CMD_NOTE_OFF:
      chan[c.chan].keyOff=true;
      chan[c.chan].active=false;
      chan[c.chan].std.init(NULL);
      break;
    case DIV_CMD_VOLUME: {
      chan[c.chan].vol=c.value;
      if (!chan[c.chan].std.hasVol) {
        chan[c.chan].outVol=c.value;
      }
      if (isMuted[c.chan]) {
        rWrite(0x19+c.chan,0);
      } else {
        rWrite(0x19+c.chan,chan[c.chan].vol&15);
      }
      break;
    }
    case DIV_CMD_GET_VOLUME: {
      return chan[c.chan].vol;
      break;
    }
    case DIV_CMD_INSTRUMENT:
      if (chan[c.chan].ins!=c.value) {
        chan[c.chan].insChanged=true;
      }
      chan[c.chan].ins=c.value;
      break;
    case DIV_CMD_PITCH: {
      chan[c.chan].pitch=c.value;
      chan[c.chan].freqChanged=true;
      break;
    }
    case DIV_CMD_NOTE_PORTA: {
      int destFreq=c.value2<<8;
      bool return2=false;
      if (destFreq>chan[c.chan].baseFreq) {
        chan[c.chan].baseFreq+=c.value;
        if (chan[c.chan].baseFreq>=destFreq) {
          chan[c.chan].baseFreq=destFreq;
          return2=true;
        }
      } else {
        chan[c.chan].baseFreq-=c.value;
        if (chan[c.chan].baseFreq<=destFreq) {
          chan[c.chan].baseFreq=destFreq;
          return2=true;
        }
      }
      chan[c.chan].freqChanged=true;
      if (return2) {
        chan[c.chan].inPorta=false;
        return 2;
      }
      break;
    }
    case DIV_CMD_LEGATO: {
      chan[c.chan].baseFreq=c.value<<8;
      chan[c.chan].freqChanged=true;
      break;
    }
    case DIV_ALWAYS_SET_VOLUME:
      return 0;
      break;
    case DIV_CMD_GET_VOLMAX:
      return 15;
      break;
    case DIV_CMD_PRE_PORTA:
      chan[c.chan].std.init(parent->getIns(chan[c.chan].ins));
      chan[c.chan].inPorta=c.value;
      break;
    case DIV_CMD_PRE_NOTE:
      break;
    default:
      //printf("WARNING: unimplemented command %d\n",c.cmd);
      break;
  }
  return 1;
}

void DivPlatformTIA::muteChannel(int ch, bool mute) {
  isMuted[ch]=mute;
  if (isMuted[ch]) {
    rWrite(0x19+ch,0);
  } else {
    rWrite(0x19+ch,chan[ch].outVol&15);
  }
}

void DivPlatformTIA::forceIns() {
  for (int i=0; i<2; i++) {
    chan[i].insChanged=true;
  }
}

void DivPlatformTIA::reset() {
  tia.reset();
  for (int i=0; i<2; i++) {
    chan[i]=DivPlatformTIA::Channel();
    chan[i].vol=0x0f;
  }
}

bool DivPlatformTIA::isStereo() {
  return false;
}

bool DivPlatformTIA::keyOffAffectsArp(int ch) {
  return true;
}

void DivPlatformTIA::notifyInsDeletion(void* ins) {
  for (int i=0; i<2; i++) {
    chan[i].std.notifyInsDeletion((DivInstrument*)ins);
  }
}

void DivPlatformTIA::setPAL(bool pal) {
  if (pal) {
    rate=31250;
  } else {
    rate=31400;
  }
}

int DivPlatformTIA::init(DivEngine* p, int channels, int sugRate, bool pal) {
  parent=p;
  skipRegisterWrites=false;
  for (int i=0; i<2; i++) {
    isMuted[i]=false;
  }
  tia.channels(1,false);
  setPAL(pal);
  reset();
  return 2;
}

void DivPlatformTIA::quit() {
}