From 650beebe99fdee4b20da4baddf9356dd188844de Mon Sep 17 00:00:00 2001
From: tildearrow <tildearrow@protonmail.com>
Date: Fri, 18 Feb 2022 12:58:36 -0500
Subject: [PATCH] split VGM ops code

---
 CMakeLists.txt         |    1 +
 src/engine/engine.cpp  | 1136 ---------------------------------------
 src/engine/engine.h    |    7 +
 src/engine/fileOps.cpp |    7 -
 src/engine/vgmOps.cpp  | 1151 ++++++++++++++++++++++++++++++++++++++++
 5 files changed, 1159 insertions(+), 1143 deletions(-)
 create mode 100644 src/engine/vgmOps.cpp

diff --git a/CMakeLists.txt b/CMakeLists.txt
index bb17f1268..ef82bf7a6 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -275,6 +275,7 @@ src/engine/playback.cpp
 src/engine/sample.cpp
 src/engine/song.cpp
 src/engine/wavetable.cpp
+src/engine/vgmOps.cpp
 src/engine/platform/abstract.cpp
 src/engine/platform/genesis.cpp
 src/engine/platform/genesisext.cpp
diff --git a/src/engine/engine.cpp b/src/engine/engine.cpp
index 1b2f18b5e..5ddfd4bdb 100644
--- a/src/engine/engine.cpp
+++ b/src/engine/engine.cpp
@@ -24,9 +24,7 @@
 #include "instrument.h"
 #include "safeReader.h"
 #include "../ta-log.h"
-#include "../ta-log.h"
 #include "../fileutils.h"
-#include "../utfutils.h"
 #include "../audio/sdl.h"
 #include <stdexcept>
 #ifndef _WIN32
@@ -1450,373 +1448,6 @@ const char* DivEngine::getEffectDesc(unsigned char effect, int chan) {
   return "Invalid effect";
 }
 
-#define addWarning(x) \
-  if (warnings.empty()) { \
-    warnings+=x; \
-  } else { \
-    warnings+=(String("\n")+x); \
-  }
-
-void DivEngine::performVGMWrite(SafeWriter* w, DivSystem sys, DivRegWrite& write, int streamOff, double* loopTimer, double* loopFreq, int* loopSample, bool isSecond) {
-  if (write.addr==0xffffffff) { // Furnace fake reset
-    switch (sys) {
-      case DIV_SYSTEM_GENESIS:
-      case DIV_SYSTEM_GENESIS_EXT:
-      case DIV_SYSTEM_YM2612:
-        for (int i=0; i<3; i++) { // set SL and RR to highest
-          w->writeC(isSecond?0xa2:0x52);
-          w->writeC(0x80+i);
-          w->writeC(0xff);
-          w->writeC(isSecond?0xa2:0x52);
-          w->writeC(0x84+i);
-          w->writeC(0xff);
-          w->writeC(isSecond?0xa2:0x52);
-          w->writeC(0x88+i);
-          w->writeC(0xff);
-          w->writeC(isSecond?0xa2:0x52);
-          w->writeC(0x8c+i);
-          w->writeC(0xff);
-
-          w->writeC(isSecond?0xa3:0x53);
-          w->writeC(0x80+i);
-          w->writeC(0xff);
-          w->writeC(isSecond?0xa3:0x53);
-          w->writeC(0x84+i);
-          w->writeC(0xff);
-          w->writeC(isSecond?0xa3:0x53);
-          w->writeC(0x88+i);
-          w->writeC(0xff);
-          w->writeC(isSecond?0xa3:0x53);
-          w->writeC(0x8c+i);
-          w->writeC(0xff);
-        }
-        for (int i=0; i<3; i++) { // note off
-          w->writeC(isSecond?0xa2:0x52);
-          w->writeC(0x28);
-          w->writeC(i);
-          w->writeC(isSecond?0xa2:0x52);
-          w->writeC(0x28);
-          w->writeC(4+i);
-        }
-        w->writeC(isSecond?0xa2:0x52); // disable DAC
-        w->writeC(0x2b);
-        w->writeC(0);
-        if (sys!=DIV_SYSTEM_YM2612) {
-          for (int i=0; i<4; i++) {
-            w->writeC(isSecond?0x30:0x50);
-            w->writeC(0x90|(i<<5)|15);
-          }
-        }
-        break;
-      case DIV_SYSTEM_SMS:
-        for (int i=0; i<4; i++) {
-          w->writeC(isSecond?0x30:0x50);
-          w->writeC(0x90|(i<<5)|15);
-        }
-        break;
-      case DIV_SYSTEM_GB:
-        // square 1
-        w->writeC(0xb3);
-        w->writeC(isSecond?0x82:2);
-        w->writeC(0);
-        w->writeC(0xb3);
-        w->writeC(isSecond?0x84:4);
-        w->writeC(0x80);
-
-        // square 2
-        w->writeC(0xb3);
-        w->writeC(isSecond?0x87:7);
-        w->writeC(0);
-        w->writeC(0xb3);
-        w->writeC(isSecond?0x89:9);
-        w->writeC(0x80);
-
-        // wave
-        w->writeC(0xb3);
-        w->writeC(isSecond?0x8c:0x0c);
-        w->writeC(0);
-        w->writeC(0xb3);
-        w->writeC(isSecond?0x8e:0x0e);
-        w->writeC(0x80);
-
-        // noise
-        w->writeC(0xb3);
-        w->writeC(isSecond?0x91:0x11);
-        w->writeC(0);
-        w->writeC(0xb3);
-        w->writeC(isSecond?0x93:0x13);
-        w->writeC(0x80);
-        break;
-      case DIV_SYSTEM_PCE:
-        for (int i=0; i<6; i++) {
-          w->writeC(0xb9);
-          w->writeC(isSecond?0x80:0);
-          w->writeC(i);
-          w->writeC(0xb9);
-          w->writeC(isSecond?0x84:4);
-          w->writeC(0);
-        }
-        break;
-      case DIV_SYSTEM_NES:
-        w->writeC(0xb4);
-        w->writeC(isSecond?0x95:0x15);
-        w->writeC(0);
-        break;
-      case DIV_SYSTEM_ARCADE:
-      case DIV_SYSTEM_YM2151:
-        for (int i=0; i<8; i++) {
-          w->writeC(isSecond?0xa4:0x54);
-          w->writeC(0xe0+i);
-          w->writeC(0xff);
-          w->writeC(isSecond?0xa4:0x54);
-          w->writeC(0xe8+i);
-          w->writeC(0xff);
-          w->writeC(isSecond?0xa4:0x54);
-          w->writeC(0xf0+i);
-          w->writeC(0xff);
-          w->writeC(isSecond?0xa4:0x54);
-          w->writeC(0xf8+i);
-          w->writeC(0xff);
-
-          w->writeC(isSecond?0xa4:0x54);
-          w->writeC(0x08);
-          w->writeC(i);
-        }
-        if (sys==DIV_SYSTEM_ARCADE) {
-          for (int i=0; i<5; i++) {
-            w->writeC(0xc0);
-            w->writeS((isSecond?0x8086:0x86)+(i<<3));
-            w->writeC(3);
-          }
-        }
-        break;
-      case DIV_SYSTEM_YM2610:
-      case DIV_SYSTEM_YM2610_FULL:
-      case DIV_SYSTEM_YM2610_EXT:
-      case DIV_SYSTEM_YM2610_FULL_EXT:
-        for (int i=0; i<2; i++) { // set SL and RR to highest
-          w->writeC(isSecond?0xa8:0x58);
-          w->writeC(0x81+i);
-          w->writeC(0xff);
-          w->writeC(isSecond?0xa8:0x58);
-          w->writeC(0x85+i);
-          w->writeC(0xff);
-          w->writeC(isSecond?0xa8:0x58);
-          w->writeC(0x89+i);
-          w->writeC(0xff);
-          w->writeC(isSecond?0xa8:0x58);
-          w->writeC(0x8d+i);
-          w->writeC(0xff);
-
-          w->writeC(isSecond?0xa9:0x59);
-          w->writeC(0x81+i);
-          w->writeC(0xff);
-          w->writeC(isSecond?0xa9:0x59);
-          w->writeC(0x85+i);
-          w->writeC(0xff);
-          w->writeC(isSecond?0xa9:0x59);
-          w->writeC(0x89+i);
-          w->writeC(0xff);
-          w->writeC(isSecond?0xa9:0x59);
-          w->writeC(0x8d+i);
-          w->writeC(0xff);
-        }
-        for (int i=0; i<2; i++) { // note off
-          w->writeC(isSecond?0xa8:0x58);
-          w->writeC(0x28);
-          w->writeC(1+i);
-          w->writeC(isSecond?0xa8:0x58);
-          w->writeC(0x28);
-          w->writeC(5+i);
-        }
-        
-        // reset AY
-        w->writeC(isSecond?0xa8:0x58);
-        w->writeC(7);
-        w->writeC(0x3f);
-
-        w->writeC(isSecond?0xa8:0x58);
-        w->writeC(8);
-        w->writeC(0);
-
-        w->writeC(isSecond?0xa8:0x58);
-        w->writeC(9);
-        w->writeC(0);
-
-        w->writeC(isSecond?0xa8:0x58);
-        w->writeC(10);
-        w->writeC(0);
-
-        // reset sample
-        w->writeC(isSecond?0xa9:0x59);
-        w->writeC(0);
-        w->writeC(0xbf);
-        break;
-      case DIV_SYSTEM_AY8910:
-        w->writeC(0xa0);
-        w->writeC(isSecond?0x87:7);
-        w->writeC(0x3f);
-
-        w->writeC(0xa0);
-        w->writeC(isSecond?0x88:8);
-        w->writeC(0);
-
-        w->writeC(0xa0);
-        w->writeC(isSecond?0x89:9);
-        w->writeC(0);
-
-        w->writeC(0xa0);
-        w->writeC(isSecond?0x8a:10);
-        w->writeC(0);
-        break;
-      case DIV_SYSTEM_AY8930:
-        w->writeC(0xa0);
-        w->writeC(isSecond?0x8d:0x0d);
-        w->writeC(0);
-        w->writeC(0xa0);
-        w->writeC(isSecond?0x8d:0x0d);
-        w->writeC(0xa0);
-        break;
-      case DIV_SYSTEM_SAA1099:
-        w->writeC(0xbd);
-        w->writeC(isSecond?0x9c:0x1c);
-        w->writeC(0x02);
-        w->writeC(0xbd);
-        w->writeC(isSecond?0x94:0x14);
-        w->writeC(0);
-        w->writeC(0xbd);
-        w->writeC(isSecond?0x95:0x15);
-        w->writeC(0);
-
-        for (int i=0; i<6; i++) {
-          w->writeC(0xbd);
-          w->writeC((isSecond?0x80:0)+i);
-          w->writeC(0);
-        }
-        break;
-      default:
-        break;
-    }
-  }
-  if (write.addr>=0xffff0000) { // Furnace special command
-    unsigned char streamID=streamOff+((write.addr&0xff00)>>8);
-    switch (write.addr&0xff) {
-      case 0: // play sample
-        if (write.val<song.sampleLen) {
-          DivSample* sample=song.sample[write.val];
-          w->writeC(0x95);
-          w->writeC(streamID);
-          w->writeS(write.val); // sample number
-          w->writeC((sample->loopStart==0)); // flags
-          if (sample->loopStart>0) {
-            loopTimer[streamID]=sample->rendLength;
-            loopSample[streamID]=write.val;
-          }
-        }
-        break;
-      case 1: // set sample freq
-        w->writeC(0x92);
-        w->writeC(streamID);
-        w->writeI(write.val);
-        loopFreq[streamID]=write.val;
-        break;
-      case 2: // stop sample
-        w->writeC(0x94);
-        w->writeC(streamID);
-        loopSample[streamID]=-1;
-        break;
-    }
-    return;
-  }
-  switch (sys) {
-    case DIV_SYSTEM_GENESIS:
-    case DIV_SYSTEM_GENESIS_EXT:
-    case DIV_SYSTEM_YM2612:
-      switch (write.addr>>8) {
-        case 0: // port 0
-          w->writeC(isSecond?0xa2:0x52);
-          w->writeC(write.addr&0xff);
-          w->writeC(write.val);
-          break;
-        case 1: // port 1
-          w->writeC(isSecond?0xa3:0x53);
-          w->writeC(write.addr&0xff);
-          w->writeC(write.val);
-          break;
-        case 2: // PSG
-          w->writeC(isSecond?0x30:0x50);
-          w->writeC(write.val);
-          break;
-      }
-      break;
-    case DIV_SYSTEM_SMS:
-      w->writeC(isSecond?0x30:0x50);
-      w->writeC(write.val);
-      break;
-    case DIV_SYSTEM_GB:
-      w->writeC(0xb3);
-      w->writeC((isSecond?0x80:0)|((write.addr-16)&0xff));
-      w->writeC(write.val);
-      break;
-    case DIV_SYSTEM_PCE:
-      w->writeC(0xb9);
-      w->writeC((isSecond?0x80:0)|(write.addr&0xff));
-      w->writeC(write.val);
-      break;
-    case DIV_SYSTEM_NES:
-      w->writeC(0xb4);
-      w->writeC((isSecond?0x80:0)|(write.addr&0xff));
-      w->writeC(write.val);
-      break;
-    case DIV_SYSTEM_ARCADE:
-    case DIV_SYSTEM_YM2151:
-      switch (write.addr>>16) {
-        case 0: // YM2151
-          w->writeC(isSecond?0xa4:0x54);
-          w->writeC(write.addr&0xff);
-          w->writeC(write.val);
-          break;
-        case 1: // SegaPCM
-          w->writeC(0xc0);
-          w->writeS((isSecond?0x8000:0)|(write.addr&0xffff));
-          w->writeC(write.val);
-          break;
-      }
-      break;
-    case DIV_SYSTEM_YM2610:
-    case DIV_SYSTEM_YM2610_FULL:
-    case DIV_SYSTEM_YM2610_EXT:
-    case DIV_SYSTEM_YM2610_FULL_EXT:
-      switch (write.addr>>8) {
-        case 0: // port 0
-          w->writeC(isSecond?0xa8:0x58);
-          w->writeC(write.addr&0xff);
-          w->writeC(write.val);
-          break;
-        case 1: // port 1
-          w->writeC(isSecond?0xa9:0x59);
-          w->writeC(write.addr&0xff);
-          w->writeC(write.val);
-          break;
-      }
-      break;
-    case DIV_SYSTEM_AY8910:
-    case DIV_SYSTEM_AY8930:
-      w->writeC(0xa0);
-      w->writeC((isSecond?0x80:0)|(write.addr&0xff));
-      w->writeC(write.val);
-      break;
-    case DIV_SYSTEM_SAA1099:
-      w->writeC(0xbd);
-      w->writeC((isSecond?0x80:0)|(write.addr&0xff));
-      w->writeC(write.val);
-      break;
-    default:
-      logW("write not handled!\n");
-      break;
-  }
-}
-
 void DivEngine::walkSong(int& loopOrder, int& loopRow, int& loopEnd) {
   loopOrder=0;
   loopRow=0;
@@ -1863,773 +1494,6 @@ void DivEngine::walkSong(int& loopOrder, int& loopRow, int& loopEnd) {
   }
 }
 
-SafeWriter* DivEngine::saveVGM(bool* sysToExport, bool loop) {
-  stop();
-  setOrder(0);
-  isBusy.lock();
-  double origRate=got.rate;
-  got.rate=44100;
-  // determine loop point
-  int loopOrder=0;
-  int loopRow=0;
-  int loopEnd=0;
-  walkSong(loopOrder,loopRow,loopEnd);
-  logI("loop point: %d %d\n",loopOrder,loopRow);
-  warnings="";
-
-  curOrder=0;
-  freelance=false;
-  playing=false;
-  extValuePresent=false;
-  remainingLoops=-1;
-
-  // play the song ourselves
-  bool done=false;
-  int writeCount=0;
-
-  int gd3Off=0;
-
-  int hasSN=0;
-  int snNoiseConfig=9;
-  int snNoiseSize=16;
-  int snFlags=0;
-  int hasOPLL=0;
-  int hasOPN2=0;
-  int hasOPM=0;
-  int hasSegaPCM=0;
-  int segaPCMOffset=0xf8000d;
-  int hasRFC=0;
-  int hasOPN=0;
-  int hasOPNA=0;
-  int hasOPNB=0;
-  int hasOPL2=0;
-  int hasOPL=0;
-  int hasY8950=0;
-  int hasOPL3=0;
-  int hasOPL4=0;
-  int hasOPX=0;
-  int hasZ280=0;
-  int hasRFC1=0;
-  int hasPWM=0;
-  int hasAY=0;
-  int ayConfig=0;
-  int ayFlags=0;
-  int hasGB=0;
-  int hasNES=0;
-  int hasMultiPCM=0;
-  int hasuPD7759=0;
-  int hasOKIM6258=0;
-  int hasK054539=0;
-  int hasOKIM6295=0;
-  int hasK051649=0;
-  int hasPCE=0;
-  int hasNamco=0;
-  int hasK053260=0;
-  int hasPOKEY=0;
-  int hasQSound=0;
-  int hasSCSP=0;
-  int hasSwan=0;
-  int hasVSU=0;
-  int hasSAA=0;
-  int hasES5503=0;
-  int hasES5505=0;
-  int hasX1=0;
-  int hasC352=0;
-  int hasGA20=0;
-
-  int howManyChips=0;
-
-  int loopPos=-1;
-  int loopTick=-1;
-
-  SafeWriter* w=new SafeWriter;
-  w->init();
-
-  // write header
-  w->write("Vgm ",4);
-  w->writeI(0); // will be written later
-  w->writeI(0x171); // VGM 1.71
-
-  bool willExport[32];
-  bool isSecond[32];
-  int streamIDs[32];
-  double loopTimer[DIV_MAX_CHANS];
-  double loopFreq[DIV_MAX_CHANS];
-  int loopSample[DIV_MAX_CHANS];
-
-  for (int i=0; i<DIV_MAX_CHANS; i++) {
-    loopTimer[i]=0;
-    loopFreq[i]=0;
-    loopSample[i]=-1;
-  }
-
-  bool writeDACSamples=false;
-  bool writeNESSamples=false;
-  bool writePCESamples=false;
-  bool writeADPCM=false;
-  bool writeSegaPCM=false;
-
-  for (int i=0; i<song.systemLen; i++) {
-    willExport[i]=false;
-    isSecond[i]=false;
-    streamIDs[i]=0;
-    if (sysToExport!=NULL) {
-      if (!sysToExport[i]) continue;
-    }
-    switch (song.system[i]) {
-      case DIV_SYSTEM_GENESIS:
-      case DIV_SYSTEM_GENESIS_EXT:
-        writeDACSamples=true;
-        if (!hasOPN2) {
-          hasOPN2=disCont[i].dispatch->chipClock;
-          willExport[i]=true;
-        } else if (!(hasOPN2&0x40000000)) {
-          isSecond[i]=true;
-          willExport[i]=true;
-          hasOPN2|=0x40000000;
-          howManyChips++;
-          addWarning("adding a compound system two times is experimental!");
-        }
-        if (!hasSN) {
-          hasSN=3579545;
-          willExport[i]=true;
-        } else if (!(hasSN&0x40000000)) {
-          isSecond[i]=true;
-          willExport[i]=true;
-          hasSN|=0x40000000;
-          howManyChips++;
-          addWarning("adding a compound system two times is experimental!");
-        }
-        break;
-      case DIV_SYSTEM_SMS:
-        if (!hasSN) {
-          hasSN=disCont[i].dispatch->chipClock;
-          willExport[i]=true;
-          switch ((song.systemFlags[i]>>2)&3) {
-            case 1: // real SN
-              snNoiseConfig=3;
-              snNoiseSize=15;
-              break;
-            case 2: // real SN atari bass (seemingly unsupported)
-              snNoiseConfig=3;
-              snNoiseSize=15;
-              break;
-            default: // Sega VDP
-              snNoiseConfig=9;
-              snNoiseSize=16;
-              break;
-          }
-        } else if (!(hasSN&0x40000000)) {
-          isSecond[i]=true;
-          willExport[i]=true;
-          hasSN|=0x40000000;
-          howManyChips++;
-        }
-        break;
-      case DIV_SYSTEM_GB:
-        if (!hasGB) {
-          hasGB=disCont[i].dispatch->chipClock;
-          willExport[i]=true;
-        } else if (!(hasGB&0x40000000)) {
-          isSecond[i]=true;
-          willExport[i]=true;
-          hasGB|=0x40000000;
-          howManyChips++;
-        }
-        break;
-      case DIV_SYSTEM_PCE:
-        if (!hasPCE) {
-          hasPCE=disCont[i].dispatch->chipClock;
-          willExport[i]=true;
-          writePCESamples=true;
-        } else if (!(hasPCE&0x40000000)) {
-          isSecond[i]=true;
-          willExport[i]=true;
-          hasPCE|=0x40000000;
-          howManyChips++;
-        }
-        break;
-      case DIV_SYSTEM_NES:
-        if (!hasNES) {
-          hasNES=disCont[i].dispatch->chipClock;
-          willExport[i]=true;
-          writeNESSamples=true;
-        } else if (!(hasNES&0x40000000)) {
-          isSecond[i]=true;
-          willExport[i]=true;
-          hasNES|=0x40000000;
-          howManyChips++;
-        }
-        break;
-      case DIV_SYSTEM_ARCADE:
-        if (!hasOPM) {
-          hasOPM=disCont[i].dispatch->chipClock;
-          willExport[i]=true;
-        } else if (!(hasOPM&0x40000000)) {
-          isSecond[i]=true;
-          willExport[i]=true;
-          hasOPM|=0x40000000;
-          howManyChips++;
-          addWarning("adding a compound system two times is experimental!");
-        }
-        if (!hasSegaPCM) {
-          hasSegaPCM=4000000;
-          willExport[i]=true;
-          writeSegaPCM=true;
-        } else if (!(hasSegaPCM&0x40000000)) {
-          isSecond[i]=true;
-          willExport[i]=true;
-          hasSegaPCM|=0x40000000;
-          howManyChips++;
-          addWarning("adding a compound system two times is experimental!");
-        }
-        break;
-      case DIV_SYSTEM_YM2610:
-      case DIV_SYSTEM_YM2610_FULL:
-      case DIV_SYSTEM_YM2610_EXT:
-      case DIV_SYSTEM_YM2610_FULL_EXT:
-        if (!hasOPNB) {
-          hasOPNB=disCont[i].dispatch->chipClock;
-          willExport[i]=true;
-          writeADPCM=true;
-        } else if (!(hasOPNB&0x40000000)) {
-          isSecond[i]=true;
-          willExport[i]=true;
-          hasOPNB|=0x40000000;
-          howManyChips++;
-        }
-        break;
-      case DIV_SYSTEM_AY8910:
-      case DIV_SYSTEM_AY8930:
-        if (!hasAY) {
-          hasAY=disCont[i].dispatch->chipClock;
-          ayConfig=(song.system[i]==DIV_SYSTEM_AY8930)?3:0;
-          ayFlags=1;
-          willExport[i]=true;
-        } else if (!(hasAY&0x40000000)) {
-          isSecond[i]=true;
-          willExport[i]=true;
-          hasAY|=0x40000000;
-          howManyChips++;
-        }
-        break;
-      case DIV_SYSTEM_SAA1099:
-        if (!hasSAA) {
-          hasSAA=disCont[i].dispatch->chipClock;
-          willExport[i]=true;
-        } else if (!(hasSAA&0x40000000)) {
-          isSecond[i]=true;
-          willExport[i]=true;
-          hasSAA|=0x40000000;
-          howManyChips++;
-        }
-        break;
-      case DIV_SYSTEM_YM2612:
-        if (!hasOPN2) {
-          hasOPN2=disCont[i].dispatch->chipClock;
-          willExport[i]=true;
-          writeDACSamples=true;
-        } else if (!(hasOPN2&0x40000000)) {
-          isSecond[i]=true;
-          willExport[i]=true;
-          hasOPN2|=0x40000000;
-          howManyChips++;
-        }
-        break;
-      case DIV_SYSTEM_YM2151:
-        if (!hasOPM) {
-          hasOPM=disCont[i].dispatch->chipClock;
-          willExport[i]=true;
-        } else if (!(hasOPM&0x40000000)) {
-          isSecond[i]=true;
-          willExport[i]=true;
-          hasOPM|=0x40000000;
-          howManyChips++;
-        }
-        break;
-      default:
-        break;
-    }
-    if (willExport[i]) {
-      disCont[i].dispatch->toggleRegisterDump(true);
-    }
-  }
-
-  //bool wantsExtraHeader=false;
-  /*for (int i=0; i<song.systemLen; i++) {
-    if (isSecond[i]) {
-      wantsExtraHeader=true;
-      break;
-    }
-  }*/
-
-  // write chips and stuff
-  w->writeI(hasSN);
-  w->writeI(hasOPLL);
-  w->writeI(0);
-  w->writeI(0); // length. will be written later
-  w->writeI(0); // loop. will be written later
-  w->writeI(0); // loop length. why is this necessary?
-  w->writeI(0); // tick rate
-  w->writeS(snNoiseConfig);
-  w->writeC(snNoiseSize);
-  w->writeC(snFlags);
-  w->writeI(hasOPN2);
-  w->writeI(hasOPM);
-  w->writeI(0); // data pointer. will be written later
-  w->writeI(hasSegaPCM);
-  w->writeI(segaPCMOffset);
-  w->writeI(hasRFC);
-  w->writeI(hasOPN);
-  w->writeI(hasOPNA);
-  w->writeI(hasOPNB);
-  w->writeI(hasOPL2);
-  w->writeI(hasOPL);
-  w->writeI(hasY8950);
-  w->writeI(hasOPL3);
-  w->writeI(hasOPL4);
-  w->writeI(hasOPX);
-  w->writeI(hasZ280);
-  w->writeI(hasRFC1);
-  w->writeI(hasPWM);
-  w->writeI(hasAY);
-  w->writeC(ayConfig);
-  w->writeC(ayFlags);
-  w->writeC(ayFlags); // OPN
-  w->writeC(ayFlags); // OPNA
-  w->writeC(0); // volume
-  w->writeC(0); // reserved
-  w->writeC(0); // loop count
-  w->writeC(0); // loop modifier
-  w->writeI(hasGB);
-  w->writeI(hasNES);
-  w->writeI(hasMultiPCM);
-  w->writeI(hasuPD7759);
-  w->writeI(hasOKIM6258);
-  w->writeC(0); // flags
-  w->writeC(0); // K flags
-  w->writeC(0); // C140 chip type
-  w->writeC(0); // reserved
-  w->writeI(hasOKIM6295);
-  w->writeI(hasK051649);
-  w->writeI(hasK054539);
-  w->writeI(hasPCE);
-  w->writeI(hasNamco);
-  w->writeI(hasK053260);
-  w->writeI(hasPOKEY);
-  w->writeI(hasQSound);
-  w->writeI(hasSCSP);
-  w->writeI(0); // extra header
-  w->writeI(hasSwan);
-  w->writeI(hasVSU);
-  w->writeI(hasSAA);
-  w->writeI(hasES5503);
-  w->writeI(hasES5505);
-  w->writeC(0); // 5503 chans
-  w->writeC(0); // 5505 chans
-  w->writeC(0); // C352 clock divider
-  w->writeC(0); // reserved
-  w->writeI(hasX1);
-  w->writeI(hasC352);
-  w->writeI(hasGA20);
-  for (int i=0; i<7; i++) { // reserved
-    w->writeI(0);
-  }
-
-  /* TODO
-  unsigned int exHeaderOff=w->tell();
-  if (wantsExtraHeader) {
-    w->writeI(4);
-    w->writeI(4);
-
-    // write clocks
-    w->writeC(howManyChips);
-  }*/
-
-  unsigned int songOff=w->tell();
-
-  // write samples
-  unsigned int sampleSeek=0;
-  for (int i=0; i<song.sampleLen; i++) {
-    DivSample* sample=song.sample[i];
-    logI("setting seek to %d\n",sampleSeek);
-    sample->rendOffContiguous=sampleSeek;
-    sampleSeek+=sample->rendLength;
-  }
-
-  if (writeDACSamples) for (int i=0; i<song.sampleLen; i++) {
-    DivSample* sample=song.sample[i];
-    w->writeC(0x67);
-    w->writeC(0x66);
-    w->writeC(0);
-    w->writeI(sample->rendLength);
-    if (sample->depth==8) {
-      for (unsigned int j=0; j<sample->rendLength; j++) {
-        w->writeC((unsigned char)sample->rendData[j]+0x80);
-      }
-    } else {
-      for (unsigned int j=0; j<sample->rendLength; j++) {
-        w->writeC(((unsigned short)sample->rendData[j]+0x8000)>>8);
-      }
-    }
-  }
-
-  if (writeNESSamples) for (int i=0; i<song.sampleLen; i++) {
-    DivSample* sample=song.sample[i];
-    w->writeC(0x67);
-    w->writeC(0x66);
-    w->writeC(7);
-    w->writeI(sample->rendLength);
-    if (sample->depth==8) {
-      for (unsigned int j=0; j<sample->rendLength; j++) {
-        w->writeC(((unsigned char)sample->rendData[j]+0x80)>>1);
-      }
-    } else {
-      for (unsigned int j=0; j<sample->rendLength; j++) {
-        w->writeC(((unsigned short)sample->rendData[j]+0x8000)>>9);
-      }
-    }
-  }
-
-  if (writePCESamples) for (int i=0; i<song.sampleLen; i++) {
-    DivSample* sample=song.sample[i];
-    w->writeC(0x67);
-    w->writeC(0x66);
-    w->writeC(5);
-    w->writeI(sample->rendLength);
-    if (sample->depth==8) {
-      for (unsigned int j=0; j<sample->rendLength; j++) {
-        w->writeC(((unsigned char)sample->rendData[j]+0x80)>>3);
-      }
-    } else {
-      for (unsigned int j=0; j<sample->rendLength; j++) {
-        w->writeC(((unsigned short)sample->rendData[j]+0x8000)>>11);
-      }
-    }
-  }
-
-  if (writeSegaPCM) {
-    unsigned char* pcmMem=new unsigned char[16777216];
-
-    size_t memPos=0;
-    for (int i=0; i<song.sampleLen; i++) {
-      DivSample* sample=song.sample[i];
-      if ((memPos&0xff0000)!=((memPos+sample->rendLength)&0xff0000)) {
-        memPos=(memPos+0xffff)&0xff0000;
-      }
-      if (memPos>=16777216) break;
-      sample->rendOffP=memPos;
-      unsigned int alignedSize=(sample->rendLength+0xff)&(~0xff);
-      unsigned int readPos=0;
-      if (alignedSize>65536) alignedSize=65536;
-      if (sample->depth==8) {
-        for (unsigned int j=0; j<alignedSize; j++) {
-          if (readPos>=sample->rendLength) {
-            if (sample->loopStart>=0 && sample->loopStart<(int)sample->rendLength) {
-              readPos=sample->loopStart;
-              pcmMem[memPos++]=((unsigned char)sample->rendData[readPos]+0x80);
-            } else {
-              pcmMem[memPos++]=0x80;
-            }
-          } else {
-            pcmMem[memPos++]=((unsigned char)sample->rendData[readPos]+0x80);
-          }
-          readPos++;
-          if (memPos>=16777216) break;
-        }
-        sample->loopOffP=readPos-sample->loopStart;
-      } else {
-        for (unsigned int j=0; j<alignedSize; j++) {
-          if (readPos>=sample->rendLength) {
-            if (sample->loopStart>=0 && sample->loopStart<(int)sample->rendLength) {
-              readPos=sample->loopStart;
-              pcmMem[memPos++]=(((unsigned short)sample->rendData[readPos]+0x8000)>>8);
-            } else {
-              pcmMem[memPos++]=0x80;
-            }
-          } else {
-            pcmMem[memPos++]=(((unsigned short)sample->rendData[readPos]+0x8000)>>8);
-          }
-          readPos++;
-          if (memPos>=16777216) break;
-        }
-        sample->loopOffP=readPos-sample->loopStart;
-      }
-      if (memPos>=16777216) break;
-    }
-
-    w->writeC(0x67);
-    w->writeC(0x66);
-    w->writeC(0x80);
-    w->writeI(memPos+8);
-    w->writeI(memPos);
-    w->writeI(0);
-    w->write(pcmMem,memPos);
-
-    delete[] pcmMem;
-  }
-
-  if (writeADPCM && adpcmMemLen>0) {
-    w->writeC(0x67);
-    w->writeC(0x66);
-    w->writeC(0x82);
-    w->writeI(adpcmMemLen+8);
-    w->writeI(adpcmMemLen);
-    w->writeI(0);
-    w->write(adpcmMem,adpcmMemLen);
-  }
-
-  // initialize streams
-  int streamID=0;
-  for (int i=0; i<song.systemLen; i++) {
-    if (!willExport[i]) continue;
-    streamIDs[i]=streamID;
-    switch (song.system[i]) {
-      case DIV_SYSTEM_GENESIS:
-      case DIV_SYSTEM_GENESIS_EXT:
-        w->writeC(0x90);
-        w->writeC(streamID);
-        w->writeC(0x02);
-        w->writeC(0); // port
-        w->writeC(0x2a); // DAC
-
-        w->writeC(0x91);
-        w->writeC(streamID);
-        w->writeC(0);
-        w->writeC(1);
-        w->writeC(0);
-
-        w->writeC(0x92);
-        w->writeC(streamID);
-        w->writeI(32000); // default
-        streamID++;
-        break;
-      case DIV_SYSTEM_NES:
-        w->writeC(0x90);
-        w->writeC(streamID);
-        w->writeC(20);
-        w->writeC(0); // port
-        w->writeC(0x11); // DAC
-
-        w->writeC(0x91);
-        w->writeC(streamID);
-        w->writeC(7);
-        w->writeC(1);
-        w->writeC(0);
-
-        w->writeC(0x92);
-        w->writeC(streamID);
-        w->writeI(32000); // default
-        streamID++;
-        break;
-      case DIV_SYSTEM_PCE:
-        for (int j=0; j<6; j++) {
-          w->writeC(0x90);
-          w->writeC(streamID);
-          w->writeC(27);
-          w->writeC(j); // port
-          w->writeC(0x06); // select+DAC
-
-          w->writeC(0x91);
-          w->writeC(streamID);
-          w->writeC(5);
-          w->writeC(1);
-          w->writeC(0);
-
-          w->writeC(0x92);
-          w->writeC(streamID);
-          w->writeI(16000); // default
-          streamID++;
-        }
-        break;
-      default:
-        break;
-    }
-  }
-
-  // write song data
-  playSub(false);
-  size_t tickCount=0;
-  bool writeLoop=false;
-  while (!done) {
-    if (loopPos==-1) {
-      if (loopOrder==curOrder && loopRow==curRow && ticks==1) {
-        writeLoop=true;
-      }
-    }
-    if (nextTick()) {
-      done=true;
-      if (!loop) {
-        for (int i=0; i<song.systemLen; i++) {
-          disCont[i].dispatch->getRegisterWrites().clear();
-        }
-        break;
-      }
-      // stop all streams
-      for (int i=0; i<streamID; i++) {
-        w->writeC(0x94);
-        w->writeC(i);
-        loopSample[i]=-1;
-      }
-    }
-    // get register dumps
-    for (int i=0; i<song.systemLen; i++) {
-      std::vector<DivRegWrite>& writes=disCont[i].dispatch->getRegisterWrites();
-      for (DivRegWrite& j: writes) {
-        performVGMWrite(w,song.system[i],j,streamIDs[i],loopTimer,loopFreq,loopSample,isSecond[i]);
-        writeCount++;
-      }
-      writes.clear();
-    }
-    // check whether we need to loop
-    int totalWait=cycles>>MASTER_CLOCK_PREC;
-    for (int i=0; i<streamID; i++) {
-      if (loopSample[i]>=0) {
-        loopTimer[i]-=(loopFreq[i]/44100.0)*(double)totalWait;
-      }
-    }
-    bool haveNegatives=false;
-    for (int i=0; i<streamID; i++) {
-      if (loopSample[i]>=0) {
-        if (loopTimer[i]<0) {
-          haveNegatives=true;
-        }
-      }
-    }
-    while (haveNegatives) {
-      // finish all negatives
-      int nextToTouch=-1;
-      for (int i=0; i<streamID; i++) {
-        if (loopSample[i]>=0) {
-          if (loopTimer[i]<0) {
-            if (nextToTouch>=0) {
-              if (loopTimer[nextToTouch]>loopTimer[i]) nextToTouch=i;
-            } else {
-              nextToTouch=i;
-            }
-          }
-        }
-      }
-      if (nextToTouch>=0) {
-        double waitTime=totalWait+(loopTimer[nextToTouch]*(44100.0/MAX(1,loopFreq[nextToTouch])));
-        if (waitTime>0) {
-          w->writeC(0x61);
-          w->writeS(waitTime);
-          printf("wait is: %f\n",waitTime);
-          totalWait-=waitTime;
-          tickCount+=waitTime;
-        }
-        if (loopSample[nextToTouch]<song.sampleLen) {
-          DivSample* sample=song.sample[loopSample[nextToTouch]];
-          // insert loop
-          if (sample->loopStart<(int)sample->rendLength) {
-            w->writeC(0x93);
-            w->writeC(nextToTouch);
-            w->writeI(sample->rendOffContiguous+sample->loopStart);
-            w->writeC(0x81);
-            w->writeI(sample->rendLength-sample->loopStart);
-          }
-        }
-        loopSample[nextToTouch]=-1;
-      } else {
-        haveNegatives=false;
-      }
-    }
-    // write wait
-    if (totalWait>0) {
-      if (totalWait==735) {
-        w->writeC(0x62);
-      } else if (totalWait==882) {
-        w->writeC(0x63);
-      } else {
-        w->writeC(0x61);
-        w->writeS(totalWait);
-      }
-      tickCount+=totalWait;
-    }
-    if (writeLoop) {
-      writeLoop=false;
-      loopPos=w->tell();
-      loopTick=tickCount;
-    }
-  }
-  // end of song
-  w->writeC(0x66);
-
-  got.rate=origRate;
-
-  for (int i=0; i<song.systemLen; i++) {
-    disCont[i].dispatch->toggleRegisterDump(false);
-  }
-
-  // write GD3 tag
-  gd3Off=w->tell();
-  w->write("Gd3 ",4);
-  w->writeI(0x100);
-  w->writeI(0); // length. will be written later
-
-  WString ws;
-  ws=utf8To16(song.name.c_str());
-  w->writeWString(ws,false); // name
-  w->writeS(0); // japanese name
-  w->writeS(0); // game name
-  w->writeS(0); // japanese game name
-  if (song.systemLen>1) {
-    ws=L"Multiple Systems";
-  } else {
-    ws=utf8To16(getSystemName(song.system[0]));
-  }
-  w->writeWString(ws,false); // system name
-  if (song.systemLen>1) {
-    ws=L"複数システム";
-  } else {
-    ws=utf8To16(getSystemNameJ(song.system[0]));
-  }
-  w->writeWString(ws,false); // japanese system name
-  ws=utf8To16(song.author.c_str());
-  w->writeWString(ws,false); // author name
-  w->writeS(0); // japanese author name
-  w->writeS(0); // date
-  w->writeWString(L"Furnace Tracker",false); // ripper
-  w->writeS(0); // notes
-
-  int gd3Len=w->tell()-gd3Off-12;
-
-  w->seek(gd3Off+8,SEEK_SET);
-  w->writeI(gd3Len);
-
-  // finish file
-  size_t len=w->size()-4;
-  w->seek(4,SEEK_SET);
-  w->writeI(len);
-  w->seek(0x14,SEEK_SET);
-  w->writeI(gd3Off-0x14);
-  w->writeI(tickCount);
-  if (loop) {
-    w->writeI(loopPos-0x1c);
-    w->writeI(tickCount-loopTick-1);
-  } else {
-    w->writeI(0);
-    w->writeI(0);
-  }
-  w->seek(0x34,SEEK_SET);
-  w->writeI(songOff-0x34);
-  /*if (wantsExtraHeader) {
-    w->seek(0xbc,SEEK_SET);
-    w->writeI(exHeaderOff-0xbc);
-  }*/
-
-  remainingLoops=-1;
-  playing=false;
-  freelance=false;
-  extValuePresent=false;
-
-  logI("%d register writes total.\n",writeCount);
-
-  isBusy.unlock();
-  return w;
-}
-
 void _runExportThread(DivEngine* caller) {
   caller->runExportThread();
 }
diff --git a/src/engine/engine.h b/src/engine/engine.h
index 46ccf9536..25e7c306d 100644
--- a/src/engine/engine.h
+++ b/src/engine/engine.h
@@ -30,6 +30,13 @@
 #include <map>
 #include <queue>
 
+#define addWarning(x) \
+  if (warnings.empty()) { \
+    warnings+=x; \
+  } else { \
+    warnings+=(String("\n")+x); \
+  }
+
 #define DIV_VERSION "0.5.7pre2"
 #define DIV_ENGINE_VERSION 50
 
diff --git a/src/engine/fileOps.cpp b/src/engine/fileOps.cpp
index 2e79e1f07..5d3ea5330 100644
--- a/src/engine/fileOps.cpp
+++ b/src/engine/fileOps.cpp
@@ -41,13 +41,6 @@ struct InflateBlock {
   }
 };
 
-#define addWarning(x) \
-  if (warnings.empty()) { \
-    warnings+=x; \
-  } else { \
-    warnings+=(String("\n")+x); \
-  }
-
 bool DivEngine::loadDMF(unsigned char* file, size_t len) {
   SafeReader reader=SafeReader(file,len);
   warnings="";
diff --git a/src/engine/vgmOps.cpp b/src/engine/vgmOps.cpp
new file mode 100644
index 000000000..84c673e57
--- /dev/null
+++ b/src/engine/vgmOps.cpp
@@ -0,0 +1,1151 @@
+/**
+ * Furnace Tracker - multi-system chiptune tracker
+ * Copyright (C) 2021-2022 tildearrow and contributors
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "engine.h"
+#include "../ta-log.h"
+#include "../utfutils.h"
+
+constexpr int MASTER_CLOCK_PREC=(sizeof(void*)==8)?8:0;
+
+void DivEngine::performVGMWrite(SafeWriter* w, DivSystem sys, DivRegWrite& write, int streamOff, double* loopTimer, double* loopFreq, int* loopSample, bool isSecond) {
+  if (write.addr==0xffffffff) { // Furnace fake reset
+    switch (sys) {
+      case DIV_SYSTEM_GENESIS:
+      case DIV_SYSTEM_GENESIS_EXT:
+      case DIV_SYSTEM_YM2612:
+        for (int i=0; i<3; i++) { // set SL and RR to highest
+          w->writeC(isSecond?0xa2:0x52);
+          w->writeC(0x80+i);
+          w->writeC(0xff);
+          w->writeC(isSecond?0xa2:0x52);
+          w->writeC(0x84+i);
+          w->writeC(0xff);
+          w->writeC(isSecond?0xa2:0x52);
+          w->writeC(0x88+i);
+          w->writeC(0xff);
+          w->writeC(isSecond?0xa2:0x52);
+          w->writeC(0x8c+i);
+          w->writeC(0xff);
+
+          w->writeC(isSecond?0xa3:0x53);
+          w->writeC(0x80+i);
+          w->writeC(0xff);
+          w->writeC(isSecond?0xa3:0x53);
+          w->writeC(0x84+i);
+          w->writeC(0xff);
+          w->writeC(isSecond?0xa3:0x53);
+          w->writeC(0x88+i);
+          w->writeC(0xff);
+          w->writeC(isSecond?0xa3:0x53);
+          w->writeC(0x8c+i);
+          w->writeC(0xff);
+        }
+        for (int i=0; i<3; i++) { // note off
+          w->writeC(isSecond?0xa2:0x52);
+          w->writeC(0x28);
+          w->writeC(i);
+          w->writeC(isSecond?0xa2:0x52);
+          w->writeC(0x28);
+          w->writeC(4+i);
+        }
+        w->writeC(isSecond?0xa2:0x52); // disable DAC
+        w->writeC(0x2b);
+        w->writeC(0);
+        if (sys!=DIV_SYSTEM_YM2612) {
+          for (int i=0; i<4; i++) {
+            w->writeC(isSecond?0x30:0x50);
+            w->writeC(0x90|(i<<5)|15);
+          }
+        }
+        break;
+      case DIV_SYSTEM_SMS:
+        for (int i=0; i<4; i++) {
+          w->writeC(isSecond?0x30:0x50);
+          w->writeC(0x90|(i<<5)|15);
+        }
+        break;
+      case DIV_SYSTEM_GB:
+        // square 1
+        w->writeC(0xb3);
+        w->writeC(isSecond?0x82:2);
+        w->writeC(0);
+        w->writeC(0xb3);
+        w->writeC(isSecond?0x84:4);
+        w->writeC(0x80);
+
+        // square 2
+        w->writeC(0xb3);
+        w->writeC(isSecond?0x87:7);
+        w->writeC(0);
+        w->writeC(0xb3);
+        w->writeC(isSecond?0x89:9);
+        w->writeC(0x80);
+
+        // wave
+        w->writeC(0xb3);
+        w->writeC(isSecond?0x8c:0x0c);
+        w->writeC(0);
+        w->writeC(0xb3);
+        w->writeC(isSecond?0x8e:0x0e);
+        w->writeC(0x80);
+
+        // noise
+        w->writeC(0xb3);
+        w->writeC(isSecond?0x91:0x11);
+        w->writeC(0);
+        w->writeC(0xb3);
+        w->writeC(isSecond?0x93:0x13);
+        w->writeC(0x80);
+        break;
+      case DIV_SYSTEM_PCE:
+        for (int i=0; i<6; i++) {
+          w->writeC(0xb9);
+          w->writeC(isSecond?0x80:0);
+          w->writeC(i);
+          w->writeC(0xb9);
+          w->writeC(isSecond?0x84:4);
+          w->writeC(0);
+        }
+        break;
+      case DIV_SYSTEM_NES:
+        w->writeC(0xb4);
+        w->writeC(isSecond?0x95:0x15);
+        w->writeC(0);
+        break;
+      case DIV_SYSTEM_ARCADE:
+      case DIV_SYSTEM_YM2151:
+        for (int i=0; i<8; i++) {
+          w->writeC(isSecond?0xa4:0x54);
+          w->writeC(0xe0+i);
+          w->writeC(0xff);
+          w->writeC(isSecond?0xa4:0x54);
+          w->writeC(0xe8+i);
+          w->writeC(0xff);
+          w->writeC(isSecond?0xa4:0x54);
+          w->writeC(0xf0+i);
+          w->writeC(0xff);
+          w->writeC(isSecond?0xa4:0x54);
+          w->writeC(0xf8+i);
+          w->writeC(0xff);
+
+          w->writeC(isSecond?0xa4:0x54);
+          w->writeC(0x08);
+          w->writeC(i);
+        }
+        if (sys==DIV_SYSTEM_ARCADE) {
+          for (int i=0; i<5; i++) {
+            w->writeC(0xc0);
+            w->writeS((isSecond?0x8086:0x86)+(i<<3));
+            w->writeC(3);
+          }
+        }
+        break;
+      case DIV_SYSTEM_YM2610:
+      case DIV_SYSTEM_YM2610_FULL:
+      case DIV_SYSTEM_YM2610_EXT:
+      case DIV_SYSTEM_YM2610_FULL_EXT:
+        for (int i=0; i<2; i++) { // set SL and RR to highest
+          w->writeC(isSecond?0xa8:0x58);
+          w->writeC(0x81+i);
+          w->writeC(0xff);
+          w->writeC(isSecond?0xa8:0x58);
+          w->writeC(0x85+i);
+          w->writeC(0xff);
+          w->writeC(isSecond?0xa8:0x58);
+          w->writeC(0x89+i);
+          w->writeC(0xff);
+          w->writeC(isSecond?0xa8:0x58);
+          w->writeC(0x8d+i);
+          w->writeC(0xff);
+
+          w->writeC(isSecond?0xa9:0x59);
+          w->writeC(0x81+i);
+          w->writeC(0xff);
+          w->writeC(isSecond?0xa9:0x59);
+          w->writeC(0x85+i);
+          w->writeC(0xff);
+          w->writeC(isSecond?0xa9:0x59);
+          w->writeC(0x89+i);
+          w->writeC(0xff);
+          w->writeC(isSecond?0xa9:0x59);
+          w->writeC(0x8d+i);
+          w->writeC(0xff);
+        }
+        for (int i=0; i<2; i++) { // note off
+          w->writeC(isSecond?0xa8:0x58);
+          w->writeC(0x28);
+          w->writeC(1+i);
+          w->writeC(isSecond?0xa8:0x58);
+          w->writeC(0x28);
+          w->writeC(5+i);
+        }
+        
+        // reset AY
+        w->writeC(isSecond?0xa8:0x58);
+        w->writeC(7);
+        w->writeC(0x3f);
+
+        w->writeC(isSecond?0xa8:0x58);
+        w->writeC(8);
+        w->writeC(0);
+
+        w->writeC(isSecond?0xa8:0x58);
+        w->writeC(9);
+        w->writeC(0);
+
+        w->writeC(isSecond?0xa8:0x58);
+        w->writeC(10);
+        w->writeC(0);
+
+        // reset sample
+        w->writeC(isSecond?0xa9:0x59);
+        w->writeC(0);
+        w->writeC(0xbf);
+        break;
+      case DIV_SYSTEM_AY8910:
+        w->writeC(0xa0);
+        w->writeC(isSecond?0x87:7);
+        w->writeC(0x3f);
+
+        w->writeC(0xa0);
+        w->writeC(isSecond?0x88:8);
+        w->writeC(0);
+
+        w->writeC(0xa0);
+        w->writeC(isSecond?0x89:9);
+        w->writeC(0);
+
+        w->writeC(0xa0);
+        w->writeC(isSecond?0x8a:10);
+        w->writeC(0);
+        break;
+      case DIV_SYSTEM_AY8930:
+        w->writeC(0xa0);
+        w->writeC(isSecond?0x8d:0x0d);
+        w->writeC(0);
+        w->writeC(0xa0);
+        w->writeC(isSecond?0x8d:0x0d);
+        w->writeC(0xa0);
+        break;
+      case DIV_SYSTEM_SAA1099:
+        w->writeC(0xbd);
+        w->writeC(isSecond?0x9c:0x1c);
+        w->writeC(0x02);
+        w->writeC(0xbd);
+        w->writeC(isSecond?0x94:0x14);
+        w->writeC(0);
+        w->writeC(0xbd);
+        w->writeC(isSecond?0x95:0x15);
+        w->writeC(0);
+
+        for (int i=0; i<6; i++) {
+          w->writeC(0xbd);
+          w->writeC((isSecond?0x80:0)+i);
+          w->writeC(0);
+        }
+        break;
+      default:
+        break;
+    }
+  }
+  if (write.addr>=0xffff0000) { // Furnace special command
+    unsigned char streamID=streamOff+((write.addr&0xff00)>>8);
+    switch (write.addr&0xff) {
+      case 0: // play sample
+        if (write.val<song.sampleLen) {
+          DivSample* sample=song.sample[write.val];
+          w->writeC(0x95);
+          w->writeC(streamID);
+          w->writeS(write.val); // sample number
+          w->writeC((sample->loopStart==0)); // flags
+          if (sample->loopStart>0) {
+            loopTimer[streamID]=sample->rendLength;
+            loopSample[streamID]=write.val;
+          }
+        }
+        break;
+      case 1: // set sample freq
+        w->writeC(0x92);
+        w->writeC(streamID);
+        w->writeI(write.val);
+        loopFreq[streamID]=write.val;
+        break;
+      case 2: // stop sample
+        w->writeC(0x94);
+        w->writeC(streamID);
+        loopSample[streamID]=-1;
+        break;
+    }
+    return;
+  }
+  switch (sys) {
+    case DIV_SYSTEM_GENESIS:
+    case DIV_SYSTEM_GENESIS_EXT:
+    case DIV_SYSTEM_YM2612:
+      switch (write.addr>>8) {
+        case 0: // port 0
+          w->writeC(isSecond?0xa2:0x52);
+          w->writeC(write.addr&0xff);
+          w->writeC(write.val);
+          break;
+        case 1: // port 1
+          w->writeC(isSecond?0xa3:0x53);
+          w->writeC(write.addr&0xff);
+          w->writeC(write.val);
+          break;
+        case 2: // PSG
+          w->writeC(isSecond?0x30:0x50);
+          w->writeC(write.val);
+          break;
+      }
+      break;
+    case DIV_SYSTEM_SMS:
+      w->writeC(isSecond?0x30:0x50);
+      w->writeC(write.val);
+      break;
+    case DIV_SYSTEM_GB:
+      w->writeC(0xb3);
+      w->writeC((isSecond?0x80:0)|((write.addr-16)&0xff));
+      w->writeC(write.val);
+      break;
+    case DIV_SYSTEM_PCE:
+      w->writeC(0xb9);
+      w->writeC((isSecond?0x80:0)|(write.addr&0xff));
+      w->writeC(write.val);
+      break;
+    case DIV_SYSTEM_NES:
+      w->writeC(0xb4);
+      w->writeC((isSecond?0x80:0)|(write.addr&0xff));
+      w->writeC(write.val);
+      break;
+    case DIV_SYSTEM_ARCADE:
+    case DIV_SYSTEM_YM2151:
+      switch (write.addr>>16) {
+        case 0: // YM2151
+          w->writeC(isSecond?0xa4:0x54);
+          w->writeC(write.addr&0xff);
+          w->writeC(write.val);
+          break;
+        case 1: // SegaPCM
+          w->writeC(0xc0);
+          w->writeS((isSecond?0x8000:0)|(write.addr&0xffff));
+          w->writeC(write.val);
+          break;
+      }
+      break;
+    case DIV_SYSTEM_YM2610:
+    case DIV_SYSTEM_YM2610_FULL:
+    case DIV_SYSTEM_YM2610_EXT:
+    case DIV_SYSTEM_YM2610_FULL_EXT:
+      switch (write.addr>>8) {
+        case 0: // port 0
+          w->writeC(isSecond?0xa8:0x58);
+          w->writeC(write.addr&0xff);
+          w->writeC(write.val);
+          break;
+        case 1: // port 1
+          w->writeC(isSecond?0xa9:0x59);
+          w->writeC(write.addr&0xff);
+          w->writeC(write.val);
+          break;
+      }
+      break;
+    case DIV_SYSTEM_AY8910:
+    case DIV_SYSTEM_AY8930:
+      w->writeC(0xa0);
+      w->writeC((isSecond?0x80:0)|(write.addr&0xff));
+      w->writeC(write.val);
+      break;
+    case DIV_SYSTEM_SAA1099:
+      w->writeC(0xbd);
+      w->writeC((isSecond?0x80:0)|(write.addr&0xff));
+      w->writeC(write.val);
+      break;
+    default:
+      logW("write not handled!\n");
+      break;
+  }
+}
+
+SafeWriter* DivEngine::saveVGM(bool* sysToExport, bool loop) {
+  stop();
+  setOrder(0);
+  isBusy.lock();
+  double origRate=got.rate;
+  got.rate=44100;
+  // determine loop point
+  int loopOrder=0;
+  int loopRow=0;
+  int loopEnd=0;
+  walkSong(loopOrder,loopRow,loopEnd);
+  logI("loop point: %d %d\n",loopOrder,loopRow);
+  warnings="";
+
+  curOrder=0;
+  freelance=false;
+  playing=false;
+  extValuePresent=false;
+  remainingLoops=-1;
+
+  // play the song ourselves
+  bool done=false;
+  int writeCount=0;
+
+  int gd3Off=0;
+
+  int hasSN=0;
+  int snNoiseConfig=9;
+  int snNoiseSize=16;
+  int snFlags=0;
+  int hasOPLL=0;
+  int hasOPN2=0;
+  int hasOPM=0;
+  int hasSegaPCM=0;
+  int segaPCMOffset=0xf8000d;
+  int hasRFC=0;
+  int hasOPN=0;
+  int hasOPNA=0;
+  int hasOPNB=0;
+  int hasOPL2=0;
+  int hasOPL=0;
+  int hasY8950=0;
+  int hasOPL3=0;
+  int hasOPL4=0;
+  int hasOPX=0;
+  int hasZ280=0;
+  int hasRFC1=0;
+  int hasPWM=0;
+  int hasAY=0;
+  int ayConfig=0;
+  int ayFlags=0;
+  int hasGB=0;
+  int hasNES=0;
+  int hasMultiPCM=0;
+  int hasuPD7759=0;
+  int hasOKIM6258=0;
+  int hasK054539=0;
+  int hasOKIM6295=0;
+  int hasK051649=0;
+  int hasPCE=0;
+  int hasNamco=0;
+  int hasK053260=0;
+  int hasPOKEY=0;
+  int hasQSound=0;
+  int hasSCSP=0;
+  int hasSwan=0;
+  int hasVSU=0;
+  int hasSAA=0;
+  int hasES5503=0;
+  int hasES5505=0;
+  int hasX1=0;
+  int hasC352=0;
+  int hasGA20=0;
+
+  int howManyChips=0;
+
+  int loopPos=-1;
+  int loopTick=-1;
+
+  SafeWriter* w=new SafeWriter;
+  w->init();
+
+  // write header
+  w->write("Vgm ",4);
+  w->writeI(0); // will be written later
+  w->writeI(0x171); // VGM 1.71
+
+  bool willExport[32];
+  bool isSecond[32];
+  int streamIDs[32];
+  double loopTimer[DIV_MAX_CHANS];
+  double loopFreq[DIV_MAX_CHANS];
+  int loopSample[DIV_MAX_CHANS];
+
+  for (int i=0; i<DIV_MAX_CHANS; i++) {
+    loopTimer[i]=0;
+    loopFreq[i]=0;
+    loopSample[i]=-1;
+  }
+
+  bool writeDACSamples=false;
+  bool writeNESSamples=false;
+  bool writePCESamples=false;
+  bool writeADPCM=false;
+  bool writeSegaPCM=false;
+
+  for (int i=0; i<song.systemLen; i++) {
+    willExport[i]=false;
+    isSecond[i]=false;
+    streamIDs[i]=0;
+    if (sysToExport!=NULL) {
+      if (!sysToExport[i]) continue;
+    }
+    switch (song.system[i]) {
+      case DIV_SYSTEM_GENESIS:
+      case DIV_SYSTEM_GENESIS_EXT:
+        writeDACSamples=true;
+        if (!hasOPN2) {
+          hasOPN2=disCont[i].dispatch->chipClock;
+          willExport[i]=true;
+        } else if (!(hasOPN2&0x40000000)) {
+          isSecond[i]=true;
+          willExport[i]=true;
+          hasOPN2|=0x40000000;
+          howManyChips++;
+          addWarning("adding a compound system two times is experimental!");
+        }
+        if (!hasSN) {
+          hasSN=3579545;
+          willExport[i]=true;
+        } else if (!(hasSN&0x40000000)) {
+          isSecond[i]=true;
+          willExport[i]=true;
+          hasSN|=0x40000000;
+          howManyChips++;
+          addWarning("adding a compound system two times is experimental!");
+        }
+        break;
+      case DIV_SYSTEM_SMS:
+        if (!hasSN) {
+          hasSN=disCont[i].dispatch->chipClock;
+          willExport[i]=true;
+          switch ((song.systemFlags[i]>>2)&3) {
+            case 1: // real SN
+              snNoiseConfig=3;
+              snNoiseSize=15;
+              break;
+            case 2: // real SN atari bass (seemingly unsupported)
+              snNoiseConfig=3;
+              snNoiseSize=15;
+              break;
+            default: // Sega VDP
+              snNoiseConfig=9;
+              snNoiseSize=16;
+              break;
+          }
+        } else if (!(hasSN&0x40000000)) {
+          isSecond[i]=true;
+          willExport[i]=true;
+          hasSN|=0x40000000;
+          howManyChips++;
+        }
+        break;
+      case DIV_SYSTEM_GB:
+        if (!hasGB) {
+          hasGB=disCont[i].dispatch->chipClock;
+          willExport[i]=true;
+        } else if (!(hasGB&0x40000000)) {
+          isSecond[i]=true;
+          willExport[i]=true;
+          hasGB|=0x40000000;
+          howManyChips++;
+        }
+        break;
+      case DIV_SYSTEM_PCE:
+        if (!hasPCE) {
+          hasPCE=disCont[i].dispatch->chipClock;
+          willExport[i]=true;
+          writePCESamples=true;
+        } else if (!(hasPCE&0x40000000)) {
+          isSecond[i]=true;
+          willExport[i]=true;
+          hasPCE|=0x40000000;
+          howManyChips++;
+        }
+        break;
+      case DIV_SYSTEM_NES:
+        if (!hasNES) {
+          hasNES=disCont[i].dispatch->chipClock;
+          willExport[i]=true;
+          writeNESSamples=true;
+        } else if (!(hasNES&0x40000000)) {
+          isSecond[i]=true;
+          willExport[i]=true;
+          hasNES|=0x40000000;
+          howManyChips++;
+        }
+        break;
+      case DIV_SYSTEM_ARCADE:
+        if (!hasOPM) {
+          hasOPM=disCont[i].dispatch->chipClock;
+          willExport[i]=true;
+        } else if (!(hasOPM&0x40000000)) {
+          isSecond[i]=true;
+          willExport[i]=true;
+          hasOPM|=0x40000000;
+          howManyChips++;
+          addWarning("adding a compound system two times is experimental!");
+        }
+        if (!hasSegaPCM) {
+          hasSegaPCM=4000000;
+          willExport[i]=true;
+          writeSegaPCM=true;
+        } else if (!(hasSegaPCM&0x40000000)) {
+          isSecond[i]=true;
+          willExport[i]=true;
+          hasSegaPCM|=0x40000000;
+          howManyChips++;
+          addWarning("adding a compound system two times is experimental!");
+        }
+        break;
+      case DIV_SYSTEM_YM2610:
+      case DIV_SYSTEM_YM2610_FULL:
+      case DIV_SYSTEM_YM2610_EXT:
+      case DIV_SYSTEM_YM2610_FULL_EXT:
+        if (!hasOPNB) {
+          hasOPNB=disCont[i].dispatch->chipClock;
+          willExport[i]=true;
+          writeADPCM=true;
+        } else if (!(hasOPNB&0x40000000)) {
+          isSecond[i]=true;
+          willExport[i]=true;
+          hasOPNB|=0x40000000;
+          howManyChips++;
+        }
+        break;
+      case DIV_SYSTEM_AY8910:
+      case DIV_SYSTEM_AY8930:
+        if (!hasAY) {
+          hasAY=disCont[i].dispatch->chipClock;
+          ayConfig=(song.system[i]==DIV_SYSTEM_AY8930)?3:0;
+          ayFlags=1;
+          willExport[i]=true;
+        } else if (!(hasAY&0x40000000)) {
+          isSecond[i]=true;
+          willExport[i]=true;
+          hasAY|=0x40000000;
+          howManyChips++;
+        }
+        break;
+      case DIV_SYSTEM_SAA1099:
+        if (!hasSAA) {
+          hasSAA=disCont[i].dispatch->chipClock;
+          willExport[i]=true;
+        } else if (!(hasSAA&0x40000000)) {
+          isSecond[i]=true;
+          willExport[i]=true;
+          hasSAA|=0x40000000;
+          howManyChips++;
+        }
+        break;
+      case DIV_SYSTEM_YM2612:
+        if (!hasOPN2) {
+          hasOPN2=disCont[i].dispatch->chipClock;
+          willExport[i]=true;
+          writeDACSamples=true;
+        } else if (!(hasOPN2&0x40000000)) {
+          isSecond[i]=true;
+          willExport[i]=true;
+          hasOPN2|=0x40000000;
+          howManyChips++;
+        }
+        break;
+      case DIV_SYSTEM_YM2151:
+        if (!hasOPM) {
+          hasOPM=disCont[i].dispatch->chipClock;
+          willExport[i]=true;
+        } else if (!(hasOPM&0x40000000)) {
+          isSecond[i]=true;
+          willExport[i]=true;
+          hasOPM|=0x40000000;
+          howManyChips++;
+        }
+        break;
+      default:
+        break;
+    }
+    if (willExport[i]) {
+      disCont[i].dispatch->toggleRegisterDump(true);
+    }
+  }
+
+  //bool wantsExtraHeader=false;
+  /*for (int i=0; i<song.systemLen; i++) {
+    if (isSecond[i]) {
+      wantsExtraHeader=true;
+      break;
+    }
+  }*/
+
+  // write chips and stuff
+  w->writeI(hasSN);
+  w->writeI(hasOPLL);
+  w->writeI(0);
+  w->writeI(0); // length. will be written later
+  w->writeI(0); // loop. will be written later
+  w->writeI(0); // loop length. why is this necessary?
+  w->writeI(0); // tick rate
+  w->writeS(snNoiseConfig);
+  w->writeC(snNoiseSize);
+  w->writeC(snFlags);
+  w->writeI(hasOPN2);
+  w->writeI(hasOPM);
+  w->writeI(0); // data pointer. will be written later
+  w->writeI(hasSegaPCM);
+  w->writeI(segaPCMOffset);
+  w->writeI(hasRFC);
+  w->writeI(hasOPN);
+  w->writeI(hasOPNA);
+  w->writeI(hasOPNB);
+  w->writeI(hasOPL2);
+  w->writeI(hasOPL);
+  w->writeI(hasY8950);
+  w->writeI(hasOPL3);
+  w->writeI(hasOPL4);
+  w->writeI(hasOPX);
+  w->writeI(hasZ280);
+  w->writeI(hasRFC1);
+  w->writeI(hasPWM);
+  w->writeI(hasAY);
+  w->writeC(ayConfig);
+  w->writeC(ayFlags);
+  w->writeC(ayFlags); // OPN
+  w->writeC(ayFlags); // OPNA
+  w->writeC(0); // volume
+  w->writeC(0); // reserved
+  w->writeC(0); // loop count
+  w->writeC(0); // loop modifier
+  w->writeI(hasGB);
+  w->writeI(hasNES);
+  w->writeI(hasMultiPCM);
+  w->writeI(hasuPD7759);
+  w->writeI(hasOKIM6258);
+  w->writeC(0); // flags
+  w->writeC(0); // K flags
+  w->writeC(0); // C140 chip type
+  w->writeC(0); // reserved
+  w->writeI(hasOKIM6295);
+  w->writeI(hasK051649);
+  w->writeI(hasK054539);
+  w->writeI(hasPCE);
+  w->writeI(hasNamco);
+  w->writeI(hasK053260);
+  w->writeI(hasPOKEY);
+  w->writeI(hasQSound);
+  w->writeI(hasSCSP);
+  w->writeI(0); // extra header
+  w->writeI(hasSwan);
+  w->writeI(hasVSU);
+  w->writeI(hasSAA);
+  w->writeI(hasES5503);
+  w->writeI(hasES5505);
+  w->writeC(0); // 5503 chans
+  w->writeC(0); // 5505 chans
+  w->writeC(0); // C352 clock divider
+  w->writeC(0); // reserved
+  w->writeI(hasX1);
+  w->writeI(hasC352);
+  w->writeI(hasGA20);
+  for (int i=0; i<7; i++) { // reserved
+    w->writeI(0);
+  }
+
+  /* TODO
+  unsigned int exHeaderOff=w->tell();
+  if (wantsExtraHeader) {
+    w->writeI(4);
+    w->writeI(4);
+
+    // write clocks
+    w->writeC(howManyChips);
+  }*/
+
+  unsigned int songOff=w->tell();
+
+  // write samples
+  unsigned int sampleSeek=0;
+  for (int i=0; i<song.sampleLen; i++) {
+    DivSample* sample=song.sample[i];
+    logI("setting seek to %d\n",sampleSeek);
+    sample->rendOffContiguous=sampleSeek;
+    sampleSeek+=sample->rendLength;
+  }
+
+  if (writeDACSamples) for (int i=0; i<song.sampleLen; i++) {
+    DivSample* sample=song.sample[i];
+    w->writeC(0x67);
+    w->writeC(0x66);
+    w->writeC(0);
+    w->writeI(sample->rendLength);
+    if (sample->depth==8) {
+      for (unsigned int j=0; j<sample->rendLength; j++) {
+        w->writeC((unsigned char)sample->rendData[j]+0x80);
+      }
+    } else {
+      for (unsigned int j=0; j<sample->rendLength; j++) {
+        w->writeC(((unsigned short)sample->rendData[j]+0x8000)>>8);
+      }
+    }
+  }
+
+  if (writeNESSamples) for (int i=0; i<song.sampleLen; i++) {
+    DivSample* sample=song.sample[i];
+    w->writeC(0x67);
+    w->writeC(0x66);
+    w->writeC(7);
+    w->writeI(sample->rendLength);
+    if (sample->depth==8) {
+      for (unsigned int j=0; j<sample->rendLength; j++) {
+        w->writeC(((unsigned char)sample->rendData[j]+0x80)>>1);
+      }
+    } else {
+      for (unsigned int j=0; j<sample->rendLength; j++) {
+        w->writeC(((unsigned short)sample->rendData[j]+0x8000)>>9);
+      }
+    }
+  }
+
+  if (writePCESamples) for (int i=0; i<song.sampleLen; i++) {
+    DivSample* sample=song.sample[i];
+    w->writeC(0x67);
+    w->writeC(0x66);
+    w->writeC(5);
+    w->writeI(sample->rendLength);
+    if (sample->depth==8) {
+      for (unsigned int j=0; j<sample->rendLength; j++) {
+        w->writeC(((unsigned char)sample->rendData[j]+0x80)>>3);
+      }
+    } else {
+      for (unsigned int j=0; j<sample->rendLength; j++) {
+        w->writeC(((unsigned short)sample->rendData[j]+0x8000)>>11);
+      }
+    }
+  }
+
+  if (writeSegaPCM) {
+    unsigned char* pcmMem=new unsigned char[16777216];
+
+    size_t memPos=0;
+    for (int i=0; i<song.sampleLen; i++) {
+      DivSample* sample=song.sample[i];
+      if ((memPos&0xff0000)!=((memPos+sample->rendLength)&0xff0000)) {
+        memPos=(memPos+0xffff)&0xff0000;
+      }
+      if (memPos>=16777216) break;
+      sample->rendOffP=memPos;
+      unsigned int alignedSize=(sample->rendLength+0xff)&(~0xff);
+      unsigned int readPos=0;
+      if (alignedSize>65536) alignedSize=65536;
+      if (sample->depth==8) {
+        for (unsigned int j=0; j<alignedSize; j++) {
+          if (readPos>=sample->rendLength) {
+            if (sample->loopStart>=0 && sample->loopStart<(int)sample->rendLength) {
+              readPos=sample->loopStart;
+              pcmMem[memPos++]=((unsigned char)sample->rendData[readPos]+0x80);
+            } else {
+              pcmMem[memPos++]=0x80;
+            }
+          } else {
+            pcmMem[memPos++]=((unsigned char)sample->rendData[readPos]+0x80);
+          }
+          readPos++;
+          if (memPos>=16777216) break;
+        }
+        sample->loopOffP=readPos-sample->loopStart;
+      } else {
+        for (unsigned int j=0; j<alignedSize; j++) {
+          if (readPos>=sample->rendLength) {
+            if (sample->loopStart>=0 && sample->loopStart<(int)sample->rendLength) {
+              readPos=sample->loopStart;
+              pcmMem[memPos++]=(((unsigned short)sample->rendData[readPos]+0x8000)>>8);
+            } else {
+              pcmMem[memPos++]=0x80;
+            }
+          } else {
+            pcmMem[memPos++]=(((unsigned short)sample->rendData[readPos]+0x8000)>>8);
+          }
+          readPos++;
+          if (memPos>=16777216) break;
+        }
+        sample->loopOffP=readPos-sample->loopStart;
+      }
+      if (memPos>=16777216) break;
+    }
+
+    w->writeC(0x67);
+    w->writeC(0x66);
+    w->writeC(0x80);
+    w->writeI(memPos+8);
+    w->writeI(memPos);
+    w->writeI(0);
+    w->write(pcmMem,memPos);
+
+    delete[] pcmMem;
+  }
+
+  if (writeADPCM && adpcmMemLen>0) {
+    w->writeC(0x67);
+    w->writeC(0x66);
+    w->writeC(0x82);
+    w->writeI(adpcmMemLen+8);
+    w->writeI(adpcmMemLen);
+    w->writeI(0);
+    w->write(adpcmMem,adpcmMemLen);
+  }
+
+  // initialize streams
+  int streamID=0;
+  for (int i=0; i<song.systemLen; i++) {
+    if (!willExport[i]) continue;
+    streamIDs[i]=streamID;
+    switch (song.system[i]) {
+      case DIV_SYSTEM_GENESIS:
+      case DIV_SYSTEM_GENESIS_EXT:
+        w->writeC(0x90);
+        w->writeC(streamID);
+        w->writeC(0x02);
+        w->writeC(0); // port
+        w->writeC(0x2a); // DAC
+
+        w->writeC(0x91);
+        w->writeC(streamID);
+        w->writeC(0);
+        w->writeC(1);
+        w->writeC(0);
+
+        w->writeC(0x92);
+        w->writeC(streamID);
+        w->writeI(32000); // default
+        streamID++;
+        break;
+      case DIV_SYSTEM_NES:
+        w->writeC(0x90);
+        w->writeC(streamID);
+        w->writeC(20);
+        w->writeC(0); // port
+        w->writeC(0x11); // DAC
+
+        w->writeC(0x91);
+        w->writeC(streamID);
+        w->writeC(7);
+        w->writeC(1);
+        w->writeC(0);
+
+        w->writeC(0x92);
+        w->writeC(streamID);
+        w->writeI(32000); // default
+        streamID++;
+        break;
+      case DIV_SYSTEM_PCE:
+        for (int j=0; j<6; j++) {
+          w->writeC(0x90);
+          w->writeC(streamID);
+          w->writeC(27);
+          w->writeC(j); // port
+          w->writeC(0x06); // select+DAC
+
+          w->writeC(0x91);
+          w->writeC(streamID);
+          w->writeC(5);
+          w->writeC(1);
+          w->writeC(0);
+
+          w->writeC(0x92);
+          w->writeC(streamID);
+          w->writeI(16000); // default
+          streamID++;
+        }
+        break;
+      default:
+        break;
+    }
+  }
+
+  // write song data
+  playSub(false);
+  size_t tickCount=0;
+  bool writeLoop=false;
+  while (!done) {
+    if (loopPos==-1) {
+      if (loopOrder==curOrder && loopRow==curRow && ticks==1) {
+        writeLoop=true;
+      }
+    }
+    if (nextTick()) {
+      done=true;
+      if (!loop) {
+        for (int i=0; i<song.systemLen; i++) {
+          disCont[i].dispatch->getRegisterWrites().clear();
+        }
+        break;
+      }
+      // stop all streams
+      for (int i=0; i<streamID; i++) {
+        w->writeC(0x94);
+        w->writeC(i);
+        loopSample[i]=-1;
+      }
+    }
+    // get register dumps
+    for (int i=0; i<song.systemLen; i++) {
+      std::vector<DivRegWrite>& writes=disCont[i].dispatch->getRegisterWrites();
+      for (DivRegWrite& j: writes) {
+        performVGMWrite(w,song.system[i],j,streamIDs[i],loopTimer,loopFreq,loopSample,isSecond[i]);
+        writeCount++;
+      }
+      writes.clear();
+    }
+    // check whether we need to loop
+    int totalWait=cycles>>MASTER_CLOCK_PREC;
+    for (int i=0; i<streamID; i++) {
+      if (loopSample[i]>=0) {
+        loopTimer[i]-=(loopFreq[i]/44100.0)*(double)totalWait;
+      }
+    }
+    bool haveNegatives=false;
+    for (int i=0; i<streamID; i++) {
+      if (loopSample[i]>=0) {
+        if (loopTimer[i]<0) {
+          haveNegatives=true;
+        }
+      }
+    }
+    while (haveNegatives) {
+      // finish all negatives
+      int nextToTouch=-1;
+      for (int i=0; i<streamID; i++) {
+        if (loopSample[i]>=0) {
+          if (loopTimer[i]<0) {
+            if (nextToTouch>=0) {
+              if (loopTimer[nextToTouch]>loopTimer[i]) nextToTouch=i;
+            } else {
+              nextToTouch=i;
+            }
+          }
+        }
+      }
+      if (nextToTouch>=0) {
+        double waitTime=totalWait+(loopTimer[nextToTouch]*(44100.0/MAX(1,loopFreq[nextToTouch])));
+        if (waitTime>0) {
+          w->writeC(0x61);
+          w->writeS(waitTime);
+          printf("wait is: %f\n",waitTime);
+          totalWait-=waitTime;
+          tickCount+=waitTime;
+        }
+        if (loopSample[nextToTouch]<song.sampleLen) {
+          DivSample* sample=song.sample[loopSample[nextToTouch]];
+          // insert loop
+          if (sample->loopStart<(int)sample->rendLength) {
+            w->writeC(0x93);
+            w->writeC(nextToTouch);
+            w->writeI(sample->rendOffContiguous+sample->loopStart);
+            w->writeC(0x81);
+            w->writeI(sample->rendLength-sample->loopStart);
+          }
+        }
+        loopSample[nextToTouch]=-1;
+      } else {
+        haveNegatives=false;
+      }
+    }
+    // write wait
+    if (totalWait>0) {
+      if (totalWait==735) {
+        w->writeC(0x62);
+      } else if (totalWait==882) {
+        w->writeC(0x63);
+      } else {
+        w->writeC(0x61);
+        w->writeS(totalWait);
+      }
+      tickCount+=totalWait;
+    }
+    if (writeLoop) {
+      writeLoop=false;
+      loopPos=w->tell();
+      loopTick=tickCount;
+    }
+  }
+  // end of song
+  w->writeC(0x66);
+
+  got.rate=origRate;
+
+  for (int i=0; i<song.systemLen; i++) {
+    disCont[i].dispatch->toggleRegisterDump(false);
+  }
+
+  // write GD3 tag
+  gd3Off=w->tell();
+  w->write("Gd3 ",4);
+  w->writeI(0x100);
+  w->writeI(0); // length. will be written later
+
+  WString ws;
+  ws=utf8To16(song.name.c_str());
+  w->writeWString(ws,false); // name
+  w->writeS(0); // japanese name
+  w->writeS(0); // game name
+  w->writeS(0); // japanese game name
+  if (song.systemLen>1) {
+    ws=L"Multiple Systems";
+  } else {
+    ws=utf8To16(getSystemName(song.system[0]));
+  }
+  w->writeWString(ws,false); // system name
+  if (song.systemLen>1) {
+    ws=L"複数システム";
+  } else {
+    ws=utf8To16(getSystemNameJ(song.system[0]));
+  }
+  w->writeWString(ws,false); // japanese system name
+  ws=utf8To16(song.author.c_str());
+  w->writeWString(ws,false); // author name
+  w->writeS(0); // japanese author name
+  w->writeS(0); // date
+  w->writeWString(L"Furnace Tracker",false); // ripper
+  w->writeS(0); // notes
+
+  int gd3Len=w->tell()-gd3Off-12;
+
+  w->seek(gd3Off+8,SEEK_SET);
+  w->writeI(gd3Len);
+
+  // finish file
+  size_t len=w->size()-4;
+  w->seek(4,SEEK_SET);
+  w->writeI(len);
+  w->seek(0x14,SEEK_SET);
+  w->writeI(gd3Off-0x14);
+  w->writeI(tickCount);
+  if (loop) {
+    w->writeI(loopPos-0x1c);
+    w->writeI(tickCount-loopTick-1);
+  } else {
+    w->writeI(0);
+    w->writeI(0);
+  }
+  w->seek(0x34,SEEK_SET);
+  w->writeI(songOff-0x34);
+  /*if (wantsExtraHeader) {
+    w->seek(0xbc,SEEK_SET);
+    w->writeI(exHeaderOff-0xbc);
+  }*/
+
+  remainingLoops=-1;
+  playing=false;
+  freelance=false;
+  extValuePresent=false;
+
+  logI("%d register writes total.\n",writeCount);
+
+  isBusy.unlock();
+  return w;
+}