AdLib emulator changes part2:

- Add new OPL emulator API (and legacy access API) in sound/fmopl.h
- Add DOSBox OPL emulator.
- Update MAME OPL emulator for the API changes.

svn-id: r40334

9 files changed, 2408 insertions, 6 deletions

diff --git a/sound/fmopl.cpp b/sound/fmopl.cpp
new file mode 100644
index 0000000000..7bc33fc724
--- /dev/null
+++ b/sound/fmopl.cpp
@@ -0,0 +1,90 @@
+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * 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.
+ *
+ * $URL$
+ * $Id$
+ */
+
+#include "sound/fmopl.h"
+
+#include "sound/softsynth/opl/dosbox.h"
+#include "sound/softsynth/opl/mame.h"
+
+namespace OPL {
+
+bool OPL::_hasInstance = false;
+
+OPL *OPL::create(kOplType type) {
+	// Simple hack to assure we only create one instance,
+	// since the DOSBox OPL emulator does not allow more than
+	// one instance.
+	assert(!_hasInstance);
+	_hasInstance = true;
+
+	if (type == kOpl2)
+		return new MAME::OPL_MAME();
+	else
+#ifndef DISABLE_DOSBOX_ADLIB
+		return new DOSBox::OPL_DOSBox(type);
+#else
+		return 0;
+#endif
+}
+
+} // end of namespace OPL
+
+void OPLDestroy(FM_OPL *OPL) {
+	delete OPL;
+}
+
+void OPLResetChip(FM_OPL *OPL) {
+	OPL->reset();
+}
+
+void OPLWrite(FM_OPL *OPL, int a, int v) {
+	OPL->write(a, v);
+}
+
+unsigned char OPLRead(FM_OPL *OPL, int a) {
+	return OPL->read(a);
+}
+
+void OPLWriteReg(FM_OPL *OPL, int r, int v) {
+	OPL->writeReg(r, v);
+}
+
+void YM3812UpdateOne(FM_OPL *OPL, int16 *buffer, int length) {
+	OPL->readBuffer(buffer, length);
+}
+
+// Factory method
+FM_OPL *makeAdlibOPL(int rate) {
+	FM_OPL *opl = OPL::OPL::create();
+
+	if (opl) {
+		if (!opl->init(rate)) {
+			delete opl;
+			opl = 0;
+		}
+	}
+
+	return opl;
+}
+
diff --git a/sound/fmopl.h b/sound/fmopl.h
new file mode 100644
index 0000000000..ad0fb9eb6f
--- /dev/null
+++ b/sound/fmopl.h
@@ -0,0 +1,123 @@
+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * 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.
+ *
+ * $URL$
+ * $Id$
+ */
+
+#ifndef SOUND_FMOPL_H
+#define SOUND_FMOPL_H
+
+#include "common/scummsys.h"
+
+namespace OPL {
+
+class OPL {
+private:
+	// TODO: This is part of a temporary HACK to allow only 1 instance
+	static bool _hasInstance;
+public:
+	virtual ~OPL() { _hasInstance = false; }
+
+	/**
+	 * OPL type to emulate.
+	 */
+	enum kOplType {
+		kOpl2,
+		kDualOpl2,
+		kOpl3
+	};
+
+	/**
+	 * Initializes the OPL emulator.
+	 *
+	 * @param rate	output sample rate
+	 * @return		true on success, false on failure
+	 */
+	virtual bool init(int rate) = 0;
+
+	/**
+	 * Reinitializes the OPL emulator
+	 */
+	virtual void reset() = 0;
+
+	/**
+	 * Writes a byte to the given I/O port.
+	 *
+	 * @param a		port address
+	 * @param v		value, which will be written
+	 */
+	virtual void write(int a, int v) = 0;
+
+	/**
+	 * Reads a byte from the given I/O port.
+	 *
+	 * @param a		port address
+	 * @return		value read
+	 */
+	virtual byte read(int a) = 0;
+
+	/**
+	 * Function to directly write to a specific OPL register.
+	 * This writes to *both* chips for a Dual OPL2.
+	 *
+	 * @param r		hardware register number to write to
+	 * @param v		value, which will be written
+	 */
+	virtual void writeReg(int r, int v) = 0;
+
+	/**
+	 * Read up to 'length' samples.
+	 *
+	 * Data will be in native endianess, 16 bit per sample, signed.
+	 * For stereo OPL, buffer will be filled with interleaved
+	 * left and right channel samples, starting with a left sample.
+	 * Furthermore, the samples in the left and right are summed up.
+	 * So if you request 4 samples from a stereo OPL, you will get
+	 * a total of two left channel and two right channel samples.
+	 */
+	virtual void readBuffer(int16 *buffer, int length) = 0;
+
+	/**
+	 * Returns whether the setup OPL mode is stereo or not
+	 */
+	virtual bool isStereo() const = 0;
+
+	static OPL *create(kOplType type = kOpl2);
+};
+
+} // end of namespace OPL
+
+// Legacy API
+typedef OPL::OPL FM_OPL;
+
+void OPLDestroy(FM_OPL *OPL);
+
+void OPLResetChip(FM_OPL *OPL);
+void OPLWrite(FM_OPL *OPL, int a, int v);
+unsigned char OPLRead(FM_OPL *OPL, int a);
+void OPLWriteReg(FM_OPL *OPL, int r, int v);
+void YM3812UpdateOne(FM_OPL *OPL, int16 *buffer, int length);
+
+// Factory method
+FM_OPL *makeAdlibOPL(int rate);
+
+#endif
+
diff --git a/sound/module.mk b/sound/module.mk
index 1d7c2ffc31..dba9501a38 100644
--- a/sound/module.mk
+++ b/sound/module.mk
@@ -7,6 +7,7 @@ MODULE_OBJS := \
 	audiostream.o \
 	iff.o \
 	flac.o \
+	fmopl.o \
 	mididrv.o \
 	midiparser.o \
 	midiparser_smf.o \
@@ -29,6 +30,7 @@ MODULE_OBJS := \
 	mods/rjp1.o \
 	mods/soundfx.o \
 	softsynth/adlib.o \
+	softsynth/opl/dosbox.o \
 	softsynth/opl/mame.o \
 	softsynth/ym2612.o \
 	softsynth/fluidsynth.o \
diff --git a/sound/softsynth/opl/dosbox.cpp b/sound/softsynth/opl/dosbox.cpp
new file mode 100644
index 0000000000..60bc417cdd
--- /dev/null
+++ b/sound/softsynth/opl/dosbox.cpp
@@ -0,0 +1,355 @@
+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * 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.
+ *
+ * $URL$
+ * $Id$
+ */
+
+/*
+ * Based on AdLib emulation code of DOSBox
+ * Copyright (C) 2002-2009  The DOSBox Team
+ * Licensed under GPLv2+
+ * http://www.dosbox.com
+ */
+
+#ifndef DISABLE_DOSBOX_OPL
+
+#include "dosbox.h"
+
+#include "common/system.h"
+
+#include <math.h>
+#include <string.h>
+
+namespace OPL {
+namespace DOSBox {	
+
+Timer::Timer() {
+	masked = false;
+	overflow = false;
+	enabled = false;
+	counter = 0;
+	delay = 0;
+}
+
+void Timer::update(double time) {
+	if (!enabled || !delay) 
+		return;
+	double deltaStart = time - startTime;
+	// Only set the overflow flag when not masked
+	if (deltaStart >= 0 && !masked)
+		overflow = 1;
+}
+
+void Timer::reset(double time) {
+	overflow = false;
+	if (!delay || !enabled)
+		return;
+	double delta = (time - startTime);
+	double rem = fmod(delta, delay);
+	double next = delay - rem;
+	startTime = time + next;		
+}
+
+void Timer::stop() {
+	enabled = false;
+}
+
+void Timer::start(double time, int scale) {
+	//Don't enable again
+	if (enabled)
+		return;
+	enabled = true;
+	delay = 0.001 * (256 - counter) * scale;
+	startTime = time + delay;
+}
+
+bool Chip::write(uint32 reg, uint8 val) {
+	switch (reg) {
+	case 0x02:
+		timer[0].counter = val;
+		return true;
+	case 0x03:
+		timer[1].counter = val;
+		return true;
+	case 0x04:
+		double time = g_system->getMillis() / 1000.0;
+
+		if (val & 0x80) {
+			timer[0].reset(time);
+			timer[1].reset(time);
+		} else {
+			timer[0].update(time);
+			timer[1].update(time);
+
+			if (val & 0x1)
+				timer[0].start(time, 80);
+			else
+				timer[0].stop();
+
+			timer[0].masked = (val & 0x40) > 0;
+
+			if (timer[0].masked)
+				timer[0].overflow = false;
+
+			if (val & 0x2)
+				timer[1].start(time, 320);
+			else
+				timer[1].stop();
+
+			timer[1].masked = (val & 0x20) > 0;
+	
+			if (timer[1].masked)
+				timer[1].overflow = false;
+		}
+		return true;
+	}
+	return false;
+}
+
+uint8 Chip::read() {
+	double time = g_system->getMillis() / 1000.0;
+
+	timer[0].update(time);
+	timer[1].update(time);
+
+	uint8 ret = 0;
+	// Overflow won't be set if a channel is masked
+	if (timer[0].overflow) {
+		ret |= 0x40;
+		ret |= 0x80;
+	}
+	if (timer[1].overflow) {
+		ret |= 0x20;
+		ret |= 0x80;
+	}
+	return ret;
+}
+
+namespace OPL2 {
+#include "opl.cpp"
+
+struct Handler : public DOSBox::Handler {
+	void writeReg(uint32 reg, uint8 val) {	
+		adlib_write(reg, val);
+	}
+
+	uint32 writeAddr(uint32 port, uint8 val) {
+		return val;
+	}
+
+	void generate(int16 *chan, uint samples) {
+		adlib_getsample(chan, samples);
+	}
+
+	void init(uint rate) {
+		adlib_init(rate);
+	}
+};
+} // end of namespace OPL2
+
+namespace OPL3 {
+#define OPLTYPE_IS_OPL3
+#include "opl.cpp"
+
+struct Handler : public DOSBox::Handler {
+	void writeReg(uint32 reg, uint8 val) {	
+		adlib_write(reg,val);
+	}
+
+	uint32 writeAddr(uint32 port, uint8 val) {
+		adlib_write_index(port, val);
+		return index;
+	}
+
+	void generate(int16 *chan, uint samples) {
+		adlib_getsample(chan, samples);
+	}
+
+	void init(uint rate) {
+		adlib_init(rate);
+	}
+};
+} // end of namespace OPL3
+
+OPL_DOSBox::OPL_DOSBox(kOplType type) : _type(type), _rate(0), _handler(0) {
+}
+
+OPL_DOSBox::~OPL_DOSBox() {
+	free();
+}
+
+void OPL_DOSBox::free() {
+	delete _handler;
+	_handler = 0;
+}
+
+bool OPL_DOSBox::init(int rate) {
+	free();
+
+	memset(&_reg, 0, sizeof(_reg));
+	memset(_chip, 0, sizeof(_chip));
+
+	switch (_type) {
+	case kOpl2:
+		_handler = new OPL2::Handler();
+		break;
+
+	case kDualOpl2:
+	case kOpl3:
+		_handler = new OPL3::Handler();
+		break;
+	
+	default:
+		return false;
+	}
+
+	_handler->init(rate);
+	_rate = rate;
+	return true;
+}
+
+void OPL_DOSBox::reset() {
+	init(_rate);	
+}
+
+void OPL_DOSBox::write(int port, int val) {
+	if (port&1) {
+		switch (_type) {
+		case kOpl2:
+		case kOpl3:
+			if (!_chip[0].write(_reg.normal, val))
+				_handler->writeReg(_reg.normal, val);
+			break;
+		case kDualOpl2:
+			// Not a 0x??8 port, then write to a specific port
+			if (!(port & 0x8)) {
+				byte index = (port & 2) >> 1;
+				dualWrite(index, _reg.dual[index], val);
+			} else {
+				//Write to both ports
+				dualWrite(0, _reg.dual[0], val);
+				dualWrite(1, _reg.dual[1], val);
+			}
+			break;
+		}
+	} else {
+		// Ask the handler to write the address
+		// Make sure to clip them in the right range
+		switch (_type) {
+		case kOpl2:
+			_reg.normal = _handler->writeAddr(port, val) & 0xff;
+			break;
+		case kOpl3:
+			_reg.normal = _handler->writeAddr(port, val) & 0x1ff;
+			break;
+		case kDualOpl2:
+			// Not a 0x?88 port, when write to a specific side
+			if (!(port & 0x8)) {
+				byte index = (port & 2) >> 1;
+				_reg.dual[index] = val & 0xff;
+			} else {
+				_reg.dual[0] = val & 0xff;
+				_reg.dual[1] = val & 0xff;
+			}
+			break;
+		}
+	}
+}
+
+byte OPL_DOSBox::read(int port) {
+	switch (_type) {
+	case kOpl2:
+		if (!(port & 1))
+			//Make sure the low bits are 6 on opl2
+			return _chip[0].read() | 0x6;
+		break;
+	case kOpl3:
+		if (!(port & 1))
+			return _chip[0].read();
+		break;
+	case kDualOpl2:
+		// Only return for the lower ports
+		if (port & 1)
+			return 0xff;
+		// Make sure the low bits are 6 on opl2
+		return _chip[(port >> 1) & 1].read() | 0x6;
+	}
+	return 0;
+}
+
+void OPL_DOSBox::writeReg(int r, int v) {
+	byte tempReg = 0;
+	switch (_type) {
+	case kOpl2:
+	case kDualOpl2:
+	case kOpl3:
+		// We can't use _handler->writeReg here directly, since it would miss timer changes.
+
+		// Backup old setup register
+		tempReg = _reg.normal;
+
+		// We need to set the register we want to write to via port 0x388
+		write(0x388, r);
+		// Do the real writing to the register
+		write(0x389, v);
+		// Restore the old register
+		write(0x388, tempReg);
+		break;
+	};
+}
+
+void OPL_DOSBox::dualWrite(uint8 index, uint8 reg, uint8 val) {
+	// Make sure you don't use opl3 features
+	// Don't allow write to disable opl3		
+	if (reg == 5)
+		return;
+
+	// Only allow 4 waveforms
+	if (reg >= 0xE0)
+		val &= 3;
+
+	// Write to the timer?
+	if (_chip[index].write(reg, val)) 
+		return;
+
+	// Enabling panning
+	if (reg >= 0xc0 && reg < 0xc8) {
+		val &= 7;
+		val |= index ? 0xA0 : 0x50;
+	}
+
+	uint32 fullReg = reg + (index ? 0x100 : 0);
+	_handler->writeReg(fullReg, val);
+}
+
+void OPL_DOSBox::readBuffer(int16 *buffer, int length) {
+	// For stereo OPL cards, we divide the sample count by 2,
+	// to match stereo AudioStream behavior.
+	if (_type != kOpl2)
+		length >>= 1;
+
+	_handler->generate(buffer, length);
+}
+
+} // end of namespace DOSBox
+} // end of namespace OPL
+
+#endif // !DISABLE_DOSBOX_ADLIB
diff --git a/sound/softsynth/opl/dosbox.h b/sound/softsynth/opl/dosbox.h
new file mode 100644
index 0000000000..f09ddf85e4
--- /dev/null
+++ b/sound/softsynth/opl/dosbox.h
@@ -0,0 +1,122 @@
+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * 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.
+ *
+ * $URL$
+ * $Id$
+ */
+
+/*
+ * Based on OPL emulation code of DOSBox
+ * Copyright (C) 2002-2009  The DOSBox Team
+ * Licensed under GPLv2+
+ * http://www.dosbox.com
+ */
+
+#ifndef SOUND_SOFTSYNTH_OPL_DOSBOX_H
+#define SOUND_SOFTSYNTH_OPL_DOSBOX_H
+
+#ifndef DISABLE_DOSBOX_OPL
+
+#include "sound/fmopl.h"
+
+namespace OPL {
+namespace DOSBox {
+
+class Handler;
+
+struct Timer {
+	double startTime;
+	double delay;
+	bool enabled, overflow, masked;
+	uint8 counter;
+
+	Timer();
+
+	//Call update before making any further changes
+	void update(double time);
+
+	//On a reset make sure the start is in sync with the next cycle
+	void reset(double time);
+
+	void stop();
+
+	void start(double time, int scale);
+};
+
+struct Chip {
+	//Last selected register
+	Timer timer[2];
+	//Check for it being a write to the timer
+	bool write(uint32 addr, uint8 val);
+	//Read the current timer state, will use current double
+	uint8 read();
+};
+
+class Handler {
+public:
+	virtual ~Handler() {}
+
+	// Write an address to a chip, returns the address the chip sets
+	virtual uint32 writeAddr(uint32 port, uint8 val) = 0;
+	// Write to a specific register in the chip
+	virtual void writeReg(uint32 addr, uint8 val) = 0;
+	// Generate a certain amount of samples
+	virtual void generate(int16 *chan, uint samples) = 0;
+	// Initialize at a specific sample rate and mode
+	virtual void init(uint rate) = 0;
+};
+
+class OPL_DOSBox : public OPL {
+private:
+	kOplType _type;
+	uint _rate;
+
+	Handler *_handler;
+	Chip _chip[2];
+	union {
+		uint16 normal;
+		uint8 dual[2];
+	} _reg;
+
+	void free();
+	void dualWrite(uint8 index, uint8 reg, uint8 val);
+public:
+	OPL_DOSBox(kOplType type);
+	~OPL_DOSBox();
+
+	bool init(int rate);
+	void reset();
+
+	void write(int a, int v);
+	byte read(int a);
+
+	void writeReg(int r, int v);
+
+	void readBuffer(int16 *buffer, int length);
+	bool isStereo() const { return _type != kOpl2; }
+};
+
+} // end of namespace DOSBox
+} // end of namespace OPL
+
+#endif // !DISABLE_DOSBOX_OPL
+
+#endif
+
diff --git a/sound/softsynth/opl/mame.cpp b/sound/softsynth/opl/mame.cpp
index 4834e586c3..6427469a59 100644
--- a/sound/softsynth/opl/mame.cpp
+++ b/sound/softsynth/opl/mame.cpp
@@ -31,12 +31,48 @@
 #include <stdarg.h>
 #include <math.h>
 
-#include "sound/fmopl.h"
+#include "mame.h"
 
 #if defined (_WIN32_WCE) || defined (__SYMBIAN32__) || defined(PALMOS_MODE) || defined(__GP32__) || defined(GP2X) || defined (__MAEMO__) || defined(__DS__) || defined (__MINT__)
 #include "common/config-manager.h"
 #endif
 
+namespace OPL {
+namespace MAME {
+
+OPL_MAME::~OPL_MAME() {
+	MAME::OPLDestroy(_opl);
+	_opl = 0;
+}
+
+bool OPL_MAME::init(int rate) {
+	if (_opl)
+		MAME::OPLDestroy(_opl);
+
+	_opl = MAME::makeAdlibOPL(rate);
+	return (_opl != 0);
+}
+
+void OPL_MAME::reset() {
+	MAME::OPLResetChip(_opl);
+}
+
+void OPL_MAME::write(int a, int v) {
+	MAME::OPLWrite(_opl, a, v);
+}
+
+byte OPL_MAME::read(int a) {
+	return MAME::OPLRead(_opl, a);
+}
+
+void OPL_MAME::writeReg(int r, int v) {
+	MAME::OPLWriteReg(_opl, r, v);
+}
+
+void OPL_MAME::readBuffer(int16 *buffer, int length) {
+	MAME::YM3812UpdateOne(_opl, buffer, length);
+}
+
 /* -------------------- preliminary define section --------------------- */
 /* attack/decay rate time rate */
 #define OPL_ARRATE     141280  /* RATE 4 =  2826.24ms @ 3.6MHz */
@@ -978,7 +1014,7 @@ static void OPL_UnLockTable(void) {
 /*******************************************************************************/
 
 /* ---------- update one of chip ----------- */
-void YM3812UpdateOne(FM_OPL *OPL, int16 *buffer, int length, int interleave) {
+void YM3812UpdateOne(FM_OPL *OPL, int16 *buffer, int length) {
 	int i;
 	int data;
 	int16 *buf = buffer;
@@ -1020,7 +1056,7 @@ void YM3812UpdateOne(FM_OPL *OPL, int16 *buffer, int length, int interleave) {
 		/* limit check */
 		data = CLIP(outd[0], OPL_MINOUT, OPL_MAXOUT);
 		/* store to sound buffer */
-		buf[i << interleave] = data >> OPL_OUTSB;
+		buf[i] = data >> OPL_OUTSB;
 	}
 
 	OPL->amsCnt = amsCnt;
@@ -1189,3 +1225,7 @@ FM_OPL *makeAdlibOPL(int rate) {
 	OPLBuildTables(env_bits, eg_ent);
 	return OPLCreate(OPL_TYPE_YM3812, 3579545, rate);
 }
+
+} // end of namespace MAME
+} // end of namespace OPL
+
diff --git a/sound/softsynth/opl/mame.h b/sound/softsynth/opl/mame.h
index 47f21c9956..a9835f3b97 100644
--- a/sound/softsynth/opl/mame.h
+++ b/sound/softsynth/opl/mame.h
@@ -26,12 +26,17 @@
  */
 
 
-#ifndef SOUND_FMOPL_H
-#define SOUND_FMOPL_H
+#ifndef SOUND_SOFTSYNTH_OPL_MAME_H
+#define SOUND_SOFTSYNTH_OPL_MAME_H
 
 #include "common/scummsys.h"
 #include "common/util.h"
 
+#include "sound/fmopl.h"
+
+namespace OPL {
+namespace MAME {
+
 enum {
 	FMOPL_ENV_BITS_HQ = 16,
 	FMOPL_ENV_BITS_MQ = 8,
@@ -165,9 +170,32 @@ int OPLWrite(FM_OPL *OPL, int a, int v);
 unsigned char OPLRead(FM_OPL *OPL, int a);
 int OPLTimerOver(FM_OPL *OPL, int c);
 void OPLWriteReg(FM_OPL *OPL, int r, int v);
-void YM3812UpdateOne(FM_OPL *OPL, int16 *buffer, int length, int interleave = 0);
+void YM3812UpdateOne(FM_OPL *OPL, int16 *buffer, int length);
 
 // Factory method
 FM_OPL *makeAdlibOPL(int rate);
 
+// OPL API implementation
+class OPL_MAME : public OPL {
+private:
+	FM_OPL *_opl;
+public:
+	OPL_MAME() : _opl(0) {}
+	~OPL_MAME();
+
+	bool init(int rate);
+	void reset();
+
+	void write(int a, int v);
+	byte read(int a);
+
+	void writeReg(int r, int v);
+
+	void readBuffer(int16 *buffer, int length);
+	bool isStereo() const { return false; }
+};
+
+} // end of namespace MAME
+} // end of namespace OPL
+
 #endif
diff --git a/sound/softsynth/opl/opl.cpp b/sound/softsynth/opl/opl.cpp
new file mode 100644
index 0000000000..416f38a8ce
--- /dev/null
+++ b/sound/softsynth/opl/opl.cpp
@@ -0,0 +1,1445 @@
+/*
+ *  Copyright (C) 2002-2009  The DOSBox Team
+ *  OPL2/OPL3 emulation library
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2.1 of the License, or (at your option) any later version.
+ * 
+ *  This library 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
+ *  Lesser General Public License for more details.
+ * 
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, write to the Free Software
+ *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+
+/*
+ * Originally based on ADLIBEMU.C, an AdLib/OPL2 emulation library by Ken Silverman
+ * Copyright (C) 1998-2001 Ken Silverman
+ * Ken Silverman's official web site: "http://www.advsys.net/ken"
+ */
+
+#include "opl.h"
+
+
+static fltype recipsamp;	// inverse of sampling rate
+static Bit16s wavtable[WAVEPREC*3];	// wave form table
+
+// vibrato/tremolo tables
+static Bit32s vib_table[VIBTAB_SIZE];
+static Bit32s trem_table[TREMTAB_SIZE*2];
+
+static Bit32s vibval_const[BLOCKBUF_SIZE];
+static Bit32s tremval_const[BLOCKBUF_SIZE];
+
+// vibrato value tables (used per-operator)
+static Bit32s vibval_var1[BLOCKBUF_SIZE];
+static Bit32s vibval_var2[BLOCKBUF_SIZE];
+
+// vibrato/trmolo value table pointers
+static Bit32s *vibval1, *vibval2, *vibval3, *vibval4;
+static Bit32s *tremval1, *tremval2, *tremval3, *tremval4;
+
+
+// key scale level lookup table
+static const fltype kslmul[4] = {
+	0.0, 0.5, 0.25, 1.0		// -> 0, 3, 1.5, 6 dB/oct
+};
+
+// frequency multiplicator lookup table
+static const fltype frqmul_tab[16] = {
+	0.5,1,2,3,4,5,6,7,8,9,10,10,12,12,15,15
+};
+// calculated frequency multiplication values (depend on sampling rate)
+static float frqmul[16];
+
+// key scale levels
+static Bit8u kslev[8][16];
+
+// map a channel number to the register offset of the modulator (=register base)
+static const Bit8u modulatorbase[9]	= {
+	0,1,2,
+	8,9,10,
+	16,17,18
+};
+
+// map a register base to a modulator operator number or operator number
+#if defined(OPLTYPE_IS_OPL3)
+static const Bit8u regbase2modop[44] = {
+	0,1,2,0,1,2,0,0,3,4,5,3,4,5,0,0,6,7,8,6,7,8,					// first set
+	18,19,20,18,19,20,0,0,21,22,23,21,22,23,0,0,24,25,26,24,25,26	// second set
+};
+static const Bit8u regbase2op[44] = {
+	0,1,2,9,10,11,0,0,3,4,5,12,13,14,0,0,6,7,8,15,16,17,			// first set
+	18,19,20,27,28,29,0,0,21,22,23,30,31,32,0,0,24,25,26,33,34,35	// second set
+};
+#else
+static const Bit8u regbase2modop[22] = {
+	0,1,2,0,1,2,0,0,3,4,5,3,4,5,0,0,6,7,8,6,7,8
+};
+static const Bit8u regbase2op[22] = {
+	0,1,2,9,10,11,0,0,3,4,5,12,13,14,0,0,6,7,8,15,16,17
+};
+#endif
+
+
+// start of the waveform
+static Bit32u waveform[8] = {
+	WAVEPREC,
+	WAVEPREC>>1,
+	WAVEPREC,
+	(WAVEPREC*3)>>2,
+	0,
+	0,
+	(WAVEPREC*5)>>2,
+	WAVEPREC<<1
+};
+
+// length of the waveform as mask
+static Bit32u wavemask[8] = {
+	WAVEPREC-1,
+	WAVEPREC-1,
+	(WAVEPREC>>1)-1,
+	(WAVEPREC>>1)-1,
+	WAVEPREC-1,
+	((WAVEPREC*3)>>2)-1,
+	WAVEPREC>>1,
+	WAVEPREC-1
+};
+
+// where the first entry resides
+static Bit32u wavestart[8] = {
+	0,
+	WAVEPREC>>1,
+	0,
+	WAVEPREC>>2,
+	0,
+	0,
+	0,
+	WAVEPREC>>3
+};
+
+// envelope generator function constants
+static fltype attackconst[4] = {1/2.82624,1/2.25280,1/1.88416,1/1.59744};
+static fltype decrelconst[4] = {1/39.28064,1/31.41608,1/26.17344,1/22.44608};
+
+
+void operator_advance(op_type* op_pt, Bit32s vib) {
+	op_pt->wfpos = op_pt->tcount;						// waveform position
+	
+	// advance waveform time
+	op_pt->tcount += op_pt->tinc;
+	op_pt->tcount += (Bit32s)(op_pt->tinc)*vib/FIXEDPT;
+
+	op_pt->generator_pos += generator_add;
+}
+
+void operator_advance_drums(op_type* op_pt1, Bit32s vib1, op_type* op_pt2, Bit32s vib2, op_type* op_pt3, Bit32s vib3) {
+	Bit32u c1 = op_pt1->tcount/FIXEDPT;
+	Bit32u c3 = op_pt3->tcount/FIXEDPT;
+	Bit32u phasebit = (((c1 & 0x88) ^ ((c1<<5) & 0x80)) | ((c3 ^ (c3<<2)) & 0x20)) ? 0x02 : 0x00;
+
+	Bit32u noisebit = rand()&1;
+
+	Bit32u snare_phase_bit = (((Bitu)((op_pt1->tcount/FIXEDPT) / 0x100))&1);
+
+	//Hihat
+	Bit32u inttm = (phasebit<<8) | (0x34<<(phasebit ^ (noisebit<<1)));
+	op_pt1->wfpos = inttm*FIXEDPT;				// waveform position
+	// advance waveform time
+	op_pt1->tcount += op_pt1->tinc;
+	op_pt1->tcount += (Bit32s)(op_pt1->tinc)*vib1/FIXEDPT;
+	op_pt1->generator_pos += generator_add;
+
+	//Snare
+	inttm = ((1+snare_phase_bit) ^ noisebit)<<8;
+	op_pt2->wfpos = inttm*FIXEDPT;				// waveform position
+	// advance waveform time
+	op_pt2->tcount += op_pt2->tinc;
+	op_pt2->tcount += (Bit32s)(op_pt2->tinc)*vib2/FIXEDPT;
+	op_pt2->generator_pos += generator_add;
+
+	//Cymbal
+	inttm = (1+phasebit)<<8;
+	op_pt3->wfpos = inttm*FIXEDPT;				// waveform position
+	// advance waveform time
+	op_pt3->tcount += op_pt3->tinc;
+	op_pt3->tcount += (Bit32s)(op_pt3->tinc)*vib3/FIXEDPT;
+	op_pt3->generator_pos += generator_add;
+}
+
+
+// output level is sustained, mode changes only when operator is turned off (->release)
+// or when the keep-sustained bit is turned off (->sustain_nokeep)
+void operator_output(op_type* op_pt, Bit32s modulator, Bit32s trem) {
+	if (op_pt->op_state != OF_TYPE_OFF) {
+		op_pt->lastcval = op_pt->cval;
+		Bit32u i = (Bit32u)((op_pt->wfpos+modulator)/FIXEDPT);
+
+		// wform: -16384 to 16383 (0x4000)
+		// trem :  32768 to 65535 (0x10000)
+		// step_amp: 0.0 to 1.0
+		// vol  : 1/2^14 to 1/2^29 (/0x4000; /1../0x8000)
+
+		op_pt->cval = (Bit32s)(op_pt->step_amp*op_pt->vol*op_pt->cur_wform[i&op_pt->cur_wmask]*trem/16.0);
+	}
+}
+
+
+// no action, operator is off
+void operator_off(op_type* /*op_pt*/) {
+}
+
+// output level is sustained, mode changes only when operator is turned off (->release)
+// or when the keep-sustained bit is turned off (->sustain_nokeep)
+void operator_sustain(op_type* op_pt) {
+	Bit32u num_steps_add = op_pt->generator_pos/FIXEDPT;	// number of (standardized) samples
+	for (Bit32u ct=0; ct<num_steps_add; ct++) {
+		op_pt->cur_env_step++;
+	}
+	op_pt->generator_pos -= num_steps_add*FIXEDPT;
+}
+
+// operator in release mode, if output level reaches zero the operator is turned off
+void operator_release(op_type* op_pt) {
+	// ??? boundary?
+	if (op_pt->amp > 0.00000001) {
+		// release phase
+		op_pt->amp *= op_pt->releasemul;
+	}
+
+	Bit32u num_steps_add = op_pt->generator_pos/FIXEDPT;	// number of (standardized) samples
+	for (Bit32u ct=0; ct<num_steps_add; ct++) {
+		op_pt->cur_env_step++;						// sample counter
+		if ((op_pt->cur_env_step & op_pt->env_step_r)==0) {
+			if (op_pt->amp <= 0.00000001) {
+				// release phase finished, turn off this operator
+				op_pt->amp = 0.0;
+				if (op_pt->op_state == OF_TYPE_REL) {
+					op_pt->op_state = OF_TYPE_OFF;
+				}
+			}
+			op_pt->step_amp = op_pt->amp;
+		}
+	}
+	op_pt->generator_pos -= num_steps_add*FIXEDPT;
+}
+
+// operator in decay mode, if sustain level is reached the output level is either
+// kept (sustain level keep enabled) or the operator is switched into release mode
+void operator_decay(op_type* op_pt) {
+	if (op_pt->amp > op_pt->sustain_level) {
+		// decay phase
+		op_pt->amp *= op_pt->decaymul;
+	}
+
+	Bit32u num_steps_add = op_pt->generator_pos/FIXEDPT;	// number of (standardized) samples
+	for (Bit32u ct=0; ct<num_steps_add; ct++) {
+		op_pt->cur_env_step++;
+		if ((op_pt->cur_env_step & op_pt->env_step_d)==0) {
+			if (op_pt->amp <= op_pt->sustain_level) {
+				// decay phase finished, sustain level reached
+				if (op_pt->sus_keep) {
+					// keep sustain level (until turned off)
+					op_pt->op_state = OF_TYPE_SUS;
+					op_pt->amp = op_pt->sustain_level;
+				} else {
+					// next: release phase
+					op_pt->op_state = OF_TYPE_SUS_NOKEEP;
+				}
+			}
+			op_pt->step_amp = op_pt->amp;
+		}
+	}
+	op_pt->generator_pos -= num_steps_add*FIXEDPT;
+}
+
+// operator in attack mode, if full output level is reached,
+// the operator is switched into decay mode
+void operator_attack(op_type* op_pt) {
+	op_pt->amp = ((op_pt->a3*op_pt->amp + op_pt->a2)*op_pt->amp + op_pt->a1)*op_pt->amp + op_pt->a0;
+
+	Bit32u num_steps_add = op_pt->generator_pos/FIXEDPT;		// number of (standardized) samples
+	for (Bit32u ct=0; ct<num_steps_add; ct++) {
+		op_pt->cur_env_step++;	// next sample
+		if ((op_pt->cur_env_step & op_pt->env_step_a)==0) {		// check if next step already reached
+			if (op_pt->amp > 1.0) {
+				// attack phase finished, next: decay
+				op_pt->op_state = OF_TYPE_DEC;
+				op_pt->amp = 1.0;
+				op_pt->step_amp = 1.0;
+			}
+			op_pt->step_skip_pos <<= 1;
+			if (op_pt->step_skip_pos==0) op_pt->step_skip_pos = 1;
+			if (op_pt->step_skip_pos & op_pt->env_step_skip_a) {	// check if required to skip next step
+				op_pt->step_amp = op_pt->amp;
+			}
+		}
+	}
+	op_pt->generator_pos -= num_steps_add*FIXEDPT;
+}
+
+
+typedef void (*optype_fptr)(op_type*);
+
+optype_fptr opfuncs[6] = {
+	operator_attack,
+	operator_decay,
+	operator_release,
+	operator_sustain,	// sustain phase (keeping level)
+	operator_release,	// sustain_nokeep phase (release-style)
+	operator_off
+};
+
+void change_attackrate(Bitu regbase, op_type* op_pt) {
+	Bits attackrate = adlibreg[ARC_ATTR_DECR+regbase]>>4;
+	if (attackrate) {
+		fltype f = (fltype)(pow(FL2,(fltype)attackrate+(op_pt->toff>>2)-1)*attackconst[op_pt->toff&3]*recipsamp);
+		// attack rate coefficients
+		op_pt->a0 = (fltype)(0.0377*f);
+		op_pt->a1 = (fltype)(10.73*f+1);
+		op_pt->a2 = (fltype)(-17.57*f);
+		op_pt->a3 = (fltype)(7.42*f);
+
+		Bits step_skip = attackrate*4 + op_pt->toff;
+		Bits steps = step_skip >> 2;
+		op_pt->env_step_a = (1<<(steps<=12?12-steps:0))-1;
+
+		Bits step_num = (step_skip<=48)?(4-(step_skip&3)):0;
+		static Bit8u step_skip_mask[5] = {0xff, 0xfe, 0xee, 0xba, 0xaa}; 
+		op_pt->env_step_skip_a = step_skip_mask[step_num];
+
+#if defined(OPLTYPE_IS_OPL3)
+		if (step_skip>=60) {
+#else
+		if (step_skip>=62) {
+#endif
+			op_pt->a0 = (fltype)(2.0);	// something that triggers an immediate transition to amp:=1.0
+			op_pt->a1 = (fltype)(0.0);
+			op_pt->a2 = (fltype)(0.0);
+			op_pt->a3 = (fltype)(0.0);
+		}
+	} else {
+		// attack disabled
+		op_pt->a0 = 0.0;
+		op_pt->a1 = 1.0;
+		op_pt->a2 = 0.0;
+		op_pt->a3 = 0.0;
+		op_pt->env_step_a = 0;
+		op_pt->env_step_skip_a = 0;
+	}
+}
+
+void change_decayrate(Bitu regbase, op_type* op_pt) {
+	Bits decayrate = adlibreg[ARC_ATTR_DECR+regbase]&15;
+	// decaymul should be 1.0 when decayrate==0
+	if (decayrate) {
+		fltype f = (fltype)(-7.4493*decrelconst[op_pt->toff&3]*recipsamp);
+		op_pt->decaymul = (fltype)(pow(FL2,f*pow(FL2,(fltype)(decayrate+(op_pt->toff>>2)))));
+		Bits steps = (decayrate*4 + op_pt->toff) >> 2;
+		op_pt->env_step_d = (1<<(steps<=12?12-steps:0))-1;
+	} else {
+		op_pt->decaymul = 1.0;
+		op_pt->env_step_d = 0;
+	}
+}
+
+void change_releaserate(Bitu regbase, op_type* op_pt) {
+	Bits releaserate = adlibreg[ARC_SUSL_RELR+regbase]&15;
+	// releasemul should be 1.0 when releaserate==0
+	if (releaserate) {
+		fltype f = (fltype)(-7.4493*decrelconst[op_pt->toff&3]*recipsamp);
+		op_pt->releasemul = (fltype)(pow(FL2,f*pow(FL2,(fltype)(releaserate+(op_pt->toff>>2)))));
+		Bits steps = (releaserate*4 + op_pt->toff) >> 2;
+		op_pt->env_step_r = (1<<(steps<=12?12-steps:0))-1;
+	} else {
+		op_pt->releasemul = 1.0;
+		op_pt->env_step_r = 0;
+	}
+}
+
+void change_sustainlevel(Bitu regbase, op_type* op_pt) {
+	Bits sustainlevel = adlibreg[ARC_SUSL_RELR+regbase]>>4;
+	// sustainlevel should be 0.0 when sustainlevel==15 (max)
+	if (sustainlevel<15) {
+		op_pt->sustain_level = (fltype)(pow(FL2,(fltype)sustainlevel * (-FL05)));
+	} else {
+		op_pt->sustain_level = 0.0;
+	}
+}
+
+void change_waveform(Bitu regbase, op_type* op_pt) {
+#if defined(OPLTYPE_IS_OPL3)
+	if (regbase>=ARC_SECONDSET) regbase -= (ARC_SECONDSET-22);	// second set starts at 22
+#endif
+	// waveform selection
+	op_pt->cur_wmask = wavemask[wave_sel[regbase]];
+	op_pt->cur_wform = &wavtable[waveform[wave_sel[regbase]]];
+	// (might need to be adapted to waveform type here...)
+}
+
+void change_keepsustain(Bitu regbase, op_type* op_pt) {
+	op_pt->sus_keep = (adlibreg[ARC_TVS_KSR_MUL+regbase]&0x20)>0;
+	if (op_pt->op_state==OF_TYPE_SUS) {
+		if (!op_pt->sus_keep) op_pt->op_state = OF_TYPE_SUS_NOKEEP;
+	} else if (op_pt->op_state==OF_TYPE_SUS_NOKEEP) {
+		if (op_pt->sus_keep) op_pt->op_state = OF_TYPE_SUS;
+	}
+}
+
+// enable/disable vibrato/tremolo LFO effects
+void change_vibrato(Bitu regbase, op_type* op_pt) {
+	op_pt->vibrato = (adlibreg[ARC_TVS_KSR_MUL+regbase]&0x40)!=0;
+	op_pt->tremolo = (adlibreg[ARC_TVS_KSR_MUL+regbase]&0x80)!=0;
+}
+
+// change amount of self-feedback
+void change_feedback(Bitu chanbase, op_type* op_pt) {
+	Bits feedback = adlibreg[ARC_FEEDBACK+chanbase]&14;
+	if (feedback) op_pt->mfbi = (Bit32s)(pow(FL2,(fltype)((feedback>>1)+8)));
+	else op_pt->mfbi = 0;
+}
+
+void change_frequency(Bitu chanbase, Bitu regbase, op_type* op_pt) {
+	// frequency
+	Bit32u frn = ((((Bit32u)adlibreg[ARC_KON_BNUM+chanbase])&3)<<8) + (Bit32u)adlibreg[ARC_FREQ_NUM+chanbase];
+	// block number/octave
+	Bit32u oct = ((((Bit32u)adlibreg[ARC_KON_BNUM+chanbase])>>2)&7);
+	op_pt->freq_high = (Bit32s)((frn>>7)&7);
+
+	// keysplit
+	Bit32u note_sel = (adlibreg[8]>>6)&1;
+	op_pt->toff = ((frn>>9)&(note_sel^1)) | ((frn>>8)&note_sel);
+	op_pt->toff += (oct<<1);
+
+	// envelope scaling (KSR)
+	if (!(adlibreg[ARC_TVS_KSR_MUL+regbase]&0x10)) op_pt->toff >>= 2;
+
+	// 20+a0+b0:
+	op_pt->tinc = (Bit32u)((((fltype)(frn<<oct))*frqmul[adlibreg[ARC_TVS_KSR_MUL+regbase]&15]));
+	// 40+a0+b0:
+	fltype vol_in = (fltype)((fltype)(adlibreg[ARC_KSL_OUTLEV+regbase]&63) +
+							kslmul[adlibreg[ARC_KSL_OUTLEV+regbase]>>6]*kslev[oct][frn>>6]);
+	op_pt->vol = (fltype)(pow(FL2,(fltype)(vol_in * -0.125 - 14)));
+
+	// operator frequency changed, care about features that depend on it
+	change_attackrate(regbase,op_pt);
+	change_decayrate(regbase,op_pt);
+	change_releaserate(regbase,op_pt);
+}
+
+void enable_operator(Bitu regbase, op_type* op_pt, Bit32u act_type) {
+	// check if this is really an off-on transition
+	if (op_pt->act_state == OP_ACT_OFF) {
+		Bits wselbase = regbase;
+		if (wselbase>=ARC_SECONDSET) wselbase -= (ARC_SECONDSET-22);	// second set starts at 22
+
+		op_pt->tcount = wavestart[wave_sel[wselbase]]*FIXEDPT;
+
+		// start with attack mode
+		op_pt->op_state = OF_TYPE_ATT;
+		op_pt->act_state |= act_type;
+	}
+}
+
+void disable_operator(op_type* op_pt, Bit32u act_type) {
+	// check if this is really an on-off transition
+	if (op_pt->act_state != OP_ACT_OFF) {
+		op_pt->act_state &= (~act_type);
+		if (op_pt->act_state == OP_ACT_OFF) {
+			if (op_pt->op_state != OF_TYPE_OFF) op_pt->op_state = OF_TYPE_REL;
+		}
+	}
+}
+
+void adlib_init(Bit32u samplerate) {
+	Bits i, j, oct;
+
+	int_samplerate = samplerate;
+
+	generator_add = (Bit32u)(INTFREQU*FIXEDPT/int_samplerate);
+
+
+	memset((void *)adlibreg,0,sizeof(adlibreg));
+	memset((void *)op,0,sizeof(op_type)*MAXOPERATORS);
+	memset((void *)wave_sel,0,sizeof(wave_sel));
+
+	for (i=0;i<MAXOPERATORS;i++) {
+		op[i].op_state = OF_TYPE_OFF;
+		op[i].act_state = OP_ACT_OFF;
+		op[i].amp = 0.0;
+		op[i].step_amp = 0.0;
+		op[i].vol = 0.0;
+		op[i].tcount = 0;
+		op[i].tinc = 0;
+		op[i].toff = 0;
+		op[i].cur_wmask = wavemask[0];
+		op[i].cur_wform = &wavtable[waveform[0]];
+		op[i].freq_high = 0;
+
+		op[i].generator_pos = 0;
+		op[i].cur_env_step = 0;
+		op[i].env_step_a = 0;
+		op[i].env_step_d = 0;
+		op[i].env_step_r = 0;
+		op[i].step_skip_pos = 0;
+		op[i].env_step_skip_a = 0;
+
+#if defined(OPLTYPE_IS_OPL3)
+		op[i].is_4op = false;
+		op[i].is_4op_attached = false;
+		op[i].left_pan = 1;
+		op[i].right_pan = 1;
+#endif
+	}
+
+	recipsamp = 1.0 / (fltype)int_samplerate;
+	for (i=15;i>=0;i--) {
+		frqmul[i] = (fltype)(frqmul_tab[i]*INTFREQU/(fltype)WAVEPREC*(fltype)FIXEDPT*recipsamp);
+	}
+
+	status = 0;
+	index = 0;
+
+
+	// create vibrato table
+	vib_table[0] = 8;
+	vib_table[1] = 4;
+	vib_table[2] = 0;
+	vib_table[3] = -4;
+	for (i=4; i<VIBTAB_SIZE; i++) vib_table[i] = vib_table[i-4]*-1;
+
+	// vibrato at ~6.1 ?? (opl3 docs say 6.1, opl4 docs say 6.0, y8950 docs say 6.4)
+	vibtab_add = static_cast<Bit32u>(VIBTAB_SIZE*FIXEDPT_LFO/8192*INTFREQU/int_samplerate);
+	vibtab_pos = 0;
+
+	for (i=0; i<BLOCKBUF_SIZE; i++) vibval_const[i] = 0;
+
+
+	// create tremolo table
+	Bit32s trem_table_int[TREMTAB_SIZE];
+	for (i=0; i<14; i++)	trem_table_int[i] = i-13;		// upwards (13 to 26 -> -0.5/6 to 0)
+	for (i=14; i<41; i++)	trem_table_int[i] = -i+14;		// downwards (26 to 0 -> 0 to -1/6)
+	for (i=41; i<53; i++)	trem_table_int[i] = i-40-26;	// upwards (1 to 12 -> -1/6 to -0.5/6)
+
+	for (i=0; i<TREMTAB_SIZE; i++) {
+		// 0.0 .. -26/26*4.8/6 == [0.0 .. -0.8], 4/53 steps == [1 .. 0.57]
+		fltype trem_val1=(fltype)(((fltype)trem_table_int[i])*4.8/26.0/6.0);				// 4.8db
+		fltype trem_val2=(fltype)((fltype)((Bit32s)(trem_table_int[i]/4))*1.2/6.0/6.0);		// 1.2db (larger stepping)
+
+		trem_table[i] = (Bit32s)(pow(FL2,trem_val1)*FIXEDPT);
+		trem_table[TREMTAB_SIZE+i] = (Bit32s)(pow(FL2,trem_val2)*FIXEDPT);
+	}
+
+	// tremolo at 3.7hz
+	tremtab_add = (Bit32u)((fltype)TREMTAB_SIZE * TREM_FREQ * FIXEDPT_LFO / (fltype)int_samplerate);
+	tremtab_pos = 0;
+
+	for (i=0; i<BLOCKBUF_SIZE; i++) tremval_const[i] = FIXEDPT;
+
+
+	static Bitu initfirstime = 0;
+	if (!initfirstime) {
+		initfirstime = 1;
+
+		// create waveform tables
+		for (i=0;i<(WAVEPREC>>1);i++) {
+			wavtable[(i<<1)  +WAVEPREC]	= (Bit16s)(16384*sin((fltype)((i<<1)  )*PI*2/WAVEPREC));
+			wavtable[(i<<1)+1+WAVEPREC]	= (Bit16s)(16384*sin((fltype)((i<<1)+1)*PI*2/WAVEPREC));
+			wavtable[i]					= wavtable[(i<<1)  +WAVEPREC];
+			// table to be verified, alternative: (zero-less)
+/*			wavtable[(i<<1)  +WAVEPREC]	= (Bit16s)(16384*sin((fltype)(((i*2+1)<<1)-1)*PI/WAVEPREC));
+			wavtable[(i<<1)+1+WAVEPREC]	= (Bit16s)(16384*sin((fltype)(((i*2+1)<<1)  )*PI/WAVEPREC));
+			wavtable[i]					= wavtable[(i<<1)-1+WAVEPREC]; */
+		}
+		for (i=0;i<(WAVEPREC>>3);i++) {
+			wavtable[i+(WAVEPREC<<1)]		= wavtable[i+(WAVEPREC>>3)]-16384;
+			wavtable[i+((WAVEPREC*17)>>3)]	= wavtable[i+(WAVEPREC>>2)]+16384;
+		}
+
+		// key scale level table verified ([table in book]*8/3)
+		kslev[7][0] = 0;	kslev[7][1] = 24;	kslev[7][2] = 32;	kslev[7][3] = 37;
+		kslev[7][4] = 40;	kslev[7][5] = 43;	kslev[7][6] = 45;	kslev[7][7] = 47;
+		kslev[7][8] = 48;
+		for (i=9;i<16;i++) kslev[7][i] = (Bit8u)(i+41);
+		for (j=6;j>=0;j--) {
+			for (i=0;i<16;i++) {
+				oct = (Bits)kslev[j+1][i]-8;
+				if (oct < 0) oct = 0;
+				kslev[j][i] = (Bit8u)oct;
+			}
+		}
+	}
+
+}
+
+
+
+void adlib_write(Bitu idx, Bit8u val) {
+	Bit32u second_set = idx&0x100;
+	adlibreg[idx] = val;
+
+	switch (idx&0xf0) {
+	case ARC_CONTROL:
+		// here we check for the second set registers, too:
+		switch (idx) {
+		case 0x02:	// timer1 counter
+		case 0x03:	// timer2 counter
+			break;
+		case 0x04:
+			// IRQ reset, timer mask/start
+			if (val&0x80) {
+				// clear IRQ bits in status register
+				status &= ~0x60;
+			} else {
+				status = 0;
+			}
+			break;
+#if defined(OPLTYPE_IS_OPL3)
+		case 0x04|ARC_SECONDSET:
+			// 4op enable/disable switches for each possible channel
+			op[0].is_4op = (val&1)>0;
+			op[3].is_4op_attached = op[0].is_4op;
+			op[1].is_4op = (val&2)>0;
+			op[4].is_4op_attached = op[1].is_4op;
+			op[2].is_4op = (val&4)>0;
+			op[5].is_4op_attached = op[2].is_4op;
+			op[18].is_4op = (val&8)>0;
+			op[21].is_4op_attached = op[18].is_4op;
+			op[19].is_4op = (val&16)>0;
+			op[22].is_4op_attached = op[19].is_4op;
+			op[20].is_4op = (val&32)>0;
+			op[23].is_4op_attached = op[20].is_4op;
+			break;
+		case 0x05|ARC_SECONDSET:
+			break;
+#endif
+		case 0x08:
+			// CSW, note select
+			break;
+		default:
+			break;
+		}
+		break;
+	case ARC_TVS_KSR_MUL:
+	case ARC_TVS_KSR_MUL+0x10: {
+		// tremolo/vibrato/sustain keeping enabled; key scale rate; frequency multiplication
+		int num = idx&7;
+		Bitu base = (idx-ARC_TVS_KSR_MUL)&0xff;
+		if ((num<6) && (base<22)) {
+			Bitu modop = regbase2modop[second_set?(base+22):base];
+			Bitu regbase = base+second_set;
+			Bitu chanbase = second_set?(modop-18+ARC_SECONDSET):modop;
+
+			// change tremolo/vibrato and sustain keeping of this operator
+			op_type* op_ptr = &op[modop+((num<3) ? 0 : 9)];
+			change_keepsustain(regbase,op_ptr);
+			change_vibrato(regbase,op_ptr);
+
+			// change frequency calculations of this operator as
+			// key scale rate and frequency multiplicator can be changed
+#if defined(OPLTYPE_IS_OPL3)
+			if ((adlibreg[0x105]&1) && (op[modop].is_4op_attached)) {
+				// operator uses frequency of channel
+				change_frequency(chanbase-3,regbase,op_ptr);
+			} else {
+				change_frequency(chanbase,regbase,op_ptr);
+			}
+#else
+			change_frequency(chanbase,base,op_ptr);
+#endif
+		}
+		}
+		break;
+	case ARC_KSL_OUTLEV:
+	case ARC_KSL_OUTLEV+0x10: {
+		// key scale level; output rate
+		int num = idx&7;
+		Bitu base = (idx-ARC_KSL_OUTLEV)&0xff;
+		if ((num<6) && (base<22)) {
+			Bitu modop = regbase2modop[second_set?(base+22):base];
+			Bitu chanbase = second_set?(modop-18+ARC_SECONDSET):modop;
+
+			// change frequency calculations of this operator as
+			// key scale level and output rate can be changed
+			op_type* op_ptr = &op[modop+((num<3) ? 0 : 9)];
+#if defined(OPLTYPE_IS_OPL3)
+			Bitu regbase = base+second_set;
+			if ((adlibreg[0x105]&1) && (op[modop].is_4op_attached)) {
+				// operator uses frequency of channel
+				change_frequency(chanbase-3,regbase,op_ptr);
+			} else {
+				change_frequency(chanbase,regbase,op_ptr);
+			}
+#else
+			change_frequency(chanbase,base,op_ptr);
+#endif
+		}
+		}
+		break;
+	case ARC_ATTR_DECR:
+	case ARC_ATTR_DECR+0x10: {
+		// attack/decay rates
+		int num = idx&7;
+		Bitu base = (idx-ARC_ATTR_DECR)&0xff;
+		if ((num<6) && (base<22)) {
+			Bitu regbase = base+second_set;
+
+			// change attack rate and decay rate of this operator
+			op_type* op_ptr = &op[regbase2op[second_set?(base+22):base]];
+			change_attackrate(regbase,op_ptr);
+			change_decayrate(regbase,op_ptr);
+		}
+		}
+		break;
+	case ARC_SUSL_RELR:
+	case ARC_SUSL_RELR+0x10: {
+		// sustain level; release rate
+		int num = idx&7;
+		Bitu base = (idx-ARC_SUSL_RELR)&0xff;
+		if ((num<6) && (base<22)) {
+			Bitu regbase = base+second_set;
+
+			// change sustain level and release rate of this operator
+			op_type* op_ptr = &op[regbase2op[second_set?(base+22):base]];
+			change_releaserate(regbase,op_ptr);
+			change_sustainlevel(regbase,op_ptr);
+		}
+		}
+		break;
+	case ARC_FREQ_NUM: {
+		// 0xa0-0xa8 low8 frequency
+		Bitu base = (idx-ARC_FREQ_NUM)&0xff;
+		if (base<9) {
+			Bits opbase = second_set?(base+18):base;
+#if defined(OPLTYPE_IS_OPL3)
+			if ((adlibreg[0x105]&1) && op[opbase].is_4op_attached) break;
+#endif
+			// regbase of modulator:
+			Bits modbase = modulatorbase[base]+second_set;
+
+			Bitu chanbase = base+second_set;
+
+			change_frequency(chanbase,modbase,&op[opbase]);
+			change_frequency(chanbase,modbase+3,&op[opbase+9]);
+#if defined(OPLTYPE_IS_OPL3)
+			// for 4op channels all four operators are modified to the frequency of the channel
+			if ((adlibreg[0x105]&1) && op[second_set?(base+18):base].is_4op) {
+				change_frequency(chanbase,modbase+8,&op[opbase+3]);
+				change_frequency(chanbase,modbase+3+8,&op[opbase+3+9]);
+			}
+#endif
+		}
+		}
+		break;
+	case ARC_KON_BNUM: {
+		if (idx == ARC_PERC_MODE) {
+#if defined(OPLTYPE_IS_OPL3)
+			if (second_set) return;
+#endif
+
+			if ((val&0x30) == 0x30) {		// BassDrum active
+				enable_operator(16,&op[6],OP_ACT_PERC);
+				change_frequency(6,16,&op[6]);
+				enable_operator(16+3,&op[6+9],OP_ACT_PERC);
+				change_frequency(6,16+3,&op[6+9]);
+			} else {
+				disable_operator(&op[6],OP_ACT_PERC);
+				disable_operator(&op[6+9],OP_ACT_PERC);
+			}
+			if ((val&0x28) == 0x28) {		// Snare active
+				enable_operator(17+3,&op[16],OP_ACT_PERC);
+				change_frequency(7,17+3,&op[16]);
+			} else {
+				disable_operator(&op[16],OP_ACT_PERC);
+			}
+			if ((val&0x24) == 0x24) {		// TomTom active
+				enable_operator(18,&op[8],OP_ACT_PERC);
+				change_frequency(8,18,&op[8]);
+			} else {
+				disable_operator(&op[8],OP_ACT_PERC);
+			}
+			if ((val&0x22) == 0x22) {		// Cymbal active
+				enable_operator(18+3,&op[8+9],OP_ACT_PERC);
+				change_frequency(8,18+3,&op[8+9]);
+			} else {
+				disable_operator(&op[8+9],OP_ACT_PERC);
+			}
+			if ((val&0x21) == 0x21) {		// Hihat active
+				enable_operator(17,&op[7],OP_ACT_PERC);
+				change_frequency(7,17,&op[7]);
+			} else {
+				disable_operator(&op[7],OP_ACT_PERC);
+			}
+
+			break;
+		}
+		// regular 0xb0-0xb8
+		Bitu base = (idx-ARC_KON_BNUM)&0xff;
+		if (base<9) {
+			Bits opbase = second_set?(base+18):base;
+#if defined(OPLTYPE_IS_OPL3)
+			if ((adlibreg[0x105]&1) && op[opbase].is_4op_attached) break;
+#endif
+			// regbase of modulator:
+			Bits modbase = modulatorbase[base]+second_set;
+
+			if (val&32) {
+				// operator switched on
+				enable_operator(modbase,&op[opbase],OP_ACT_NORMAL);		// modulator (if 2op)
+				enable_operator(modbase+3,&op[opbase+9],OP_ACT_NORMAL);	// carrier (if 2op)
+#if defined(OPLTYPE_IS_OPL3)
+				// for 4op channels all four operators are switched on
+				if ((adlibreg[0x105]&1) && op[opbase].is_4op) {
+					// turn on chan+3 operators as well
+					enable_operator(modbase+8,&op[opbase+3],OP_ACT_NORMAL);
+					enable_operator(modbase+3+8,&op[opbase+3+9],OP_ACT_NORMAL);
+				}
+#endif
+			} else {
+				// operator switched off
+				disable_operator(&op[opbase],OP_ACT_NORMAL);
+				disable_operator(&op[opbase+9],OP_ACT_NORMAL);
+#if defined(OPLTYPE_IS_OPL3)
+				// for 4op channels all four operators are switched off
+				if ((adlibreg[0x105]&1) && op[opbase].is_4op) {
+					// turn off chan+3 operators as well
+					disable_operator(&op[opbase+3],OP_ACT_NORMAL);
+					disable_operator(&op[opbase+3+9],OP_ACT_NORMAL);
+				}
+#endif
+			}
+
+			Bitu chanbase = base+second_set;
+
+			// change frequency calculations of modulator and carrier (2op) as
+			// the frequency of the channel has changed
+			change_frequency(chanbase,modbase,&op[opbase]);
+			change_frequency(chanbase,modbase+3,&op[opbase+9]);
+#if defined(OPLTYPE_IS_OPL3)
+			// for 4op channels all four operators are modified to the frequency of the channel
+			if ((adlibreg[0x105]&1) && op[second_set?(base+18):base].is_4op) {
+				// change frequency calculations of chan+3 operators as well
+				change_frequency(chanbase,modbase+8,&op[opbase+3]);
+				change_frequency(chanbase,modbase+3+8,&op[opbase+3+9]);
+			}
+#endif
+		}
+		}
+		break;
+	case ARC_FEEDBACK: {
+		// 0xc0-0xc8 feedback/modulation type (AM/FM)
+		Bitu base = (idx-ARC_FEEDBACK)&0xff;
+		if (base<9) {
+			Bits opbase = second_set?(base+18):base;
+			Bitu chanbase = base+second_set;
+			change_feedback(chanbase,&op[opbase]);
+#if defined(OPLTYPE_IS_OPL3)
+			// OPL3 panning
+			op[opbase].left_pan = ((val&0x10)>>4);
+			op[opbase].right_pan = ((val&0x20)>>5);
+#endif
+		}
+		}
+		break;
+	case ARC_WAVE_SEL:
+	case ARC_WAVE_SEL+0x10: {
+		int num = idx&7;
+		Bitu base = (idx-ARC_WAVE_SEL)&0xff;
+		if ((num<6) && (base<22)) {
+#if defined(OPLTYPE_IS_OPL3)
+			Bits wselbase = second_set?(base+22):base;	// for easier mapping onto wave_sel[]
+			// change waveform
+			if (adlibreg[0x105]&1) wave_sel[wselbase] = val&7;	// opl3 mode enabled, all waveforms accessible
+			else wave_sel[wselbase] = val&3;
+			op_type* op_ptr = &op[regbase2modop[wselbase]+((num<3) ? 0 : 9)];
+			change_waveform(wselbase,op_ptr);
+#else
+			if (adlibreg[0x01]&0x20) {
+				// wave selection enabled, change waveform
+				wave_sel[base] = val&3;
+				op_type* op_ptr = &op[regbase2modop[base]+((num<3) ? 0 : 9)];
+				change_waveform(base,op_ptr);
+			}
+#endif
+		}
+		}
+		break;
+	default:
+		break;
+	}
+}
+
+
+Bitu adlib_reg_read(Bitu port) {
+#if defined(OPLTYPE_IS_OPL3)
+	// opl3-detection routines require ret&6 to be zero
+	if ((port&1)==0) {
+		return status;
+	}
+	return 0x00;
+#else
+	// opl2-detection routines require ret&6 to be 6
+	if ((port&1)==0) {
+		return status|6;
+	}
+	return 0xff;
+#endif
+}
+
+void adlib_write_index(Bitu port, Bit8u val) {
+	index = val;
+#if defined(OPLTYPE_IS_OPL3)
+	if ((port&3)!=0) {
+		// possibly second set
+		if (((adlibreg[0x105]&1)!=0) || (index==5)) index |= ARC_SECONDSET;
+	}
+#endif
+}
+
+static inline void clipit16(Bit32s ival, Bit16s* outval) {
+	if (ival<32768) {
+		if (ival>-32769) {
+			*outval=(Bit16s)ival;
+		} else {
+			*outval = -32768;
+		}
+	} else {
+		*outval = 32767;
+	}
+}
+
+
+
+// be careful with this
+// uses cptr and chanval, outputs into outbufl(/outbufr)
+// for opl3 check if opl3-mode is enabled (which uses stereo panning)
+#undef CHANVAL_OUT
+#if defined(OPLTYPE_IS_OPL3)
+#define CHANVAL_OUT									\
+	if (adlibreg[0x105]&1) {						\
+		outbufl[i] += chanval*cptr[0].left_pan;		\
+		outbufr[i] += chanval*cptr[0].right_pan;	\
+	} else {										\
+		outbufl[i] += chanval;						\
+	}
+#else
+#define CHANVAL_OUT									\
+	outbufl[i] += chanval;
+#endif
+
+void adlib_getsample(Bit16s* sndptr, Bits numsamples) {
+	Bits i, endsamples;
+	op_type* cptr;
+
+	Bit32s outbufl[BLOCKBUF_SIZE];
+#if defined(OPLTYPE_IS_OPL3)
+	// second output buffer (right channel for opl3 stereo)
+	Bit32s outbufr[BLOCKBUF_SIZE];
+#endif
+
+	// vibrato/tremolo lookup tables (global, to possibly be used by all operators)
+	Bit32s vib_lut[BLOCKBUF_SIZE];
+	Bit32s trem_lut[BLOCKBUF_SIZE];
+
+	Bits samples_to_process = numsamples;
+
+	for (Bits cursmp=0; cursmp<samples_to_process; cursmp+=endsamples) {
+		endsamples = samples_to_process-cursmp;
+		if (endsamples>BLOCKBUF_SIZE) endsamples = BLOCKBUF_SIZE;
+
+		memset((void*)&outbufl,0,endsamples*sizeof(Bit32s));
+#if defined(OPLTYPE_IS_OPL3)
+		// clear second output buffer (opl3 stereo)
+		if (adlibreg[0x105]&1) memset((void*)&outbufr,0,endsamples*sizeof(Bit32s));
+#endif
+
+		// calculate vibrato/tremolo lookup tables
+		Bit32s vib_tshift = ((adlibreg[ARC_PERC_MODE]&0x40)==0) ? 1 : 0;	// 14cents/7cents switching
+		for (i=0;i<endsamples;i++) {
+			// cycle through vibrato table
+			vibtab_pos += vibtab_add;
+			if (vibtab_pos/FIXEDPT_LFO>=VIBTAB_SIZE) vibtab_pos-=VIBTAB_SIZE*FIXEDPT_LFO;
+			vib_lut[i] = vib_table[vibtab_pos/FIXEDPT_LFO]>>vib_tshift;		// 14cents (14/100 of a semitone) or 7cents
+
+			// cycle through tremolo table
+			tremtab_pos += tremtab_add;
+			if (tremtab_pos/FIXEDPT_LFO>=TREMTAB_SIZE) tremtab_pos-=TREMTAB_SIZE*FIXEDPT_LFO;
+			if (adlibreg[ARC_PERC_MODE]&0x80) trem_lut[i] = trem_table[tremtab_pos/FIXEDPT_LFO];
+			else trem_lut[i] = trem_table[TREMTAB_SIZE+tremtab_pos/FIXEDPT_LFO];
+		}
+
+		if (adlibreg[ARC_PERC_MODE]&0x20) {
+			//BassDrum
+			cptr = &op[6];
+			if (adlibreg[ARC_FEEDBACK+6]&1) {
+				// additive synthesis
+				if (cptr[9].op_state != OF_TYPE_OFF) {
+					if (cptr[9].vibrato) {
+						vibval1 = vibval_var1;
+						for (i=0;i<endsamples;i++)
+							vibval1[i] = (Bit32s)((vib_lut[i]*cptr[9].freq_high/8)*FIXEDPT*VIBFAC);
+					} else vibval1 = vibval_const;
+					if (cptr[9].tremolo) tremval1 = trem_lut;	// tremolo enabled, use table
+					else tremval1 = tremval_const;
+
+					// calculate channel output
+					for (i=0;i<endsamples;i++) {
+						operator_advance(&cptr[9],vibval1[i]);
+						opfuncs[cptr[9].op_state](&cptr[9]);
+						operator_output(&cptr[9],0,tremval1[i]);
+						
+						Bit32s chanval = cptr[9].cval*2;
+						CHANVAL_OUT
+					}
+				}
+			} else {
+				// frequency modulation
+				if ((cptr[9].op_state != OF_TYPE_OFF) || (cptr[0].op_state != OF_TYPE_OFF)) {
+					if ((cptr[0].vibrato) && (cptr[0].op_state != OF_TYPE_OFF)) {
+						vibval1 = vibval_var1;
+						for (i=0;i<endsamples;i++)
+							vibval1[i] = (Bit32s)((vib_lut[i]*cptr[0].freq_high/8)*FIXEDPT*VIBFAC);
+					} else vibval1 = vibval_const;
+					if ((cptr[9].vibrato) && (cptr[9].op_state != OF_TYPE_OFF)) {
+						vibval2 = vibval_var2;
+						for (i=0;i<endsamples;i++)
+							vibval2[i] = (Bit32s)((vib_lut[i]*cptr[9].freq_high/8)*FIXEDPT*VIBFAC);
+					} else vibval2 = vibval_const;
+					if (cptr[0].tremolo) tremval1 = trem_lut;	// tremolo enabled, use table
+					else tremval1 = tremval_const;
+					if (cptr[9].tremolo) tremval2 = trem_lut;	// tremolo enabled, use table
+					else tremval2 = tremval_const;
+
+					// calculate channel output
+					for (i=0;i<endsamples;i++) {
+						operator_advance(&cptr[0],vibval1[i]);
+						opfuncs[cptr[0].op_state](&cptr[0]);
+						operator_output(&cptr[0],(cptr[0].lastcval+cptr[0].cval)*cptr[0].mfbi/2,tremval1[i]);
+
+						operator_advance(&cptr[9],vibval2[i]);
+						opfuncs[cptr[9].op_state](&cptr[9]);
+						operator_output(&cptr[9],cptr[0].cval*FIXEDPT,tremval2[i]);
+						
+						Bit32s chanval = cptr[9].cval*2;
+						CHANVAL_OUT
+					}
+				}
+			}
+
+			//TomTom (j=8)
+			if (op[8].op_state != OF_TYPE_OFF) {
+				cptr = &op[8];
+				if (cptr[0].vibrato) {
+					vibval3 = vibval_var1;
+					for (i=0;i<endsamples;i++)
+						vibval3[i] = (Bit32s)((vib_lut[i]*cptr[0].freq_high/8)*FIXEDPT*VIBFAC);
+				} else vibval3 = vibval_const;
+
+				if (cptr[0].tremolo) tremval3 = trem_lut;	// tremolo enabled, use table
+				else tremval3 = tremval_const;
+
+				// calculate channel output
+				for (i=0;i<endsamples;i++) {
+					operator_advance(&cptr[0],vibval3[i]);
+					opfuncs[cptr[0].op_state](&cptr[0]);		//TomTom
+					operator_output(&cptr[0],0,tremval3[i]);
+					Bit32s chanval = cptr[0].cval*2;
+					CHANVAL_OUT
+				}
+			}
+
+			//Snare/Hihat (j=7), Cymbal (j=8)
+			if ((op[7].op_state != OF_TYPE_OFF) || (op[16].op_state != OF_TYPE_OFF) ||
+				(op[17].op_state != OF_TYPE_OFF)) {
+				cptr = &op[7];
+				if ((cptr[0].vibrato) && (cptr[0].op_state != OF_TYPE_OFF)) {
+					vibval1 = vibval_var1;
+					for (i=0;i<endsamples;i++)
+						vibval1[i] = (Bit32s)((vib_lut[i]*cptr[0].freq_high/8)*FIXEDPT*VIBFAC);
+				} else vibval1 = vibval_const;
+				if ((cptr[9].vibrato) && (cptr[9].op_state == OF_TYPE_OFF)) {
+					vibval2 = vibval_var2;
+					for (i=0;i<endsamples;i++)
+						vibval2[i] = (Bit32s)((vib_lut[i]*cptr[9].freq_high/8)*FIXEDPT*VIBFAC);
+				} else vibval2 = vibval_const;
+
+				if (cptr[0].tremolo) tremval1 = trem_lut;	// tremolo enabled, use table
+				else tremval1 = tremval_const;
+				if (cptr[9].tremolo) tremval2 = trem_lut;	// tremolo enabled, use table
+				else tremval2 = tremval_const;
+
+				cptr = &op[8];
+				if ((cptr[9].vibrato) && (cptr[9].op_state == OF_TYPE_OFF)) {
+					vibval4 = vibval_var2;
+					for (i=0;i<endsamples;i++)
+						vibval4[i] = (Bit32s)((vib_lut[i]*cptr[9].freq_high/8)*FIXEDPT*VIBFAC);
+				} else vibval4 = vibval_const;
+
+				if (cptr[9].tremolo) tremval4 = trem_lut;	// tremolo enabled, use table
+				else tremval4 = tremval_const;
+
+				// calculate channel output
+				for (i=0;i<endsamples;i++) {
+					operator_advance_drums(&op[7],vibval1[i],&op[7+9],vibval2[i],&op[8+9],vibval4[i]);
+
+					opfuncs[op[7].op_state](&op[7]);			//Hihat
+					operator_output(&op[7],0,tremval1[i]);
+
+					opfuncs[op[7+9].op_state](&op[7+9]);		//Snare
+					operator_output(&op[7+9],0,tremval2[i]);
+
+					opfuncs[op[8+9].op_state](&op[8+9]);		//Cymbal
+					operator_output(&op[8+9],0,tremval4[i]);
+
+					Bit32s chanval = (op[7].cval + op[7+9].cval + op[8+9].cval)*2;
+					CHANVAL_OUT
+				}
+			}
+		}
+
+		Bitu max_channel = NUM_CHANNELS;
+#if defined(OPLTYPE_IS_OPL3)
+		if ((adlibreg[0x105]&1)==0) max_channel = NUM_CHANNELS/2;
+#endif
+		for (Bits cur_ch=max_channel-1; cur_ch>=0; cur_ch--) {
+			// skip drum/percussion operators
+			if ((adlibreg[ARC_PERC_MODE]&0x20) && (cur_ch >= 6) && (cur_ch < 9)) continue;
+
+			Bitu k = cur_ch;
+#if defined(OPLTYPE_IS_OPL3)
+			if (cur_ch < 9) {
+				cptr = &op[cur_ch];
+			} else {
+				cptr = &op[cur_ch+9];	// second set is operator18-operator35
+				k += (-9+256);		// second set uses registers 0x100 onwards
+			}
+			// check if this operator is part of a 4-op
+			if ((adlibreg[0x105]&1) && cptr->is_4op_attached) continue;
+#else
+			cptr = &op[cur_ch];
+#endif
+
+			// check for FM/AM
+			if (adlibreg[ARC_FEEDBACK+k]&1) {
+#if defined(OPLTYPE_IS_OPL3)
+				if ((adlibreg[0x105]&1) && cptr->is_4op) {
+					if (adlibreg[ARC_FEEDBACK+k+3]&1) {
+						// AM-AM-style synthesis (op1[fb] + (op2 * op3) + op4)
+						if (cptr[0].op_state != OF_TYPE_OFF) {
+							if (cptr[0].vibrato) {
+								vibval1 = vibval_var1;
+								for (i=0;i<endsamples;i++)
+									vibval1[i] = (Bit32s)((vib_lut[i]*cptr[0].freq_high/8)*FIXEDPT*VIBFAC);
+							} else vibval1 = vibval_const;
+							if (cptr[0].tremolo) tremval1 = trem_lut;	// tremolo enabled, use table
+							else tremval1 = tremval_const;
+
+							// calculate channel output
+							for (i=0;i<endsamples;i++) {
+								operator_advance(&cptr[0],vibval1[i]);
+								opfuncs[cptr[0].op_state](&cptr[0]);
+								operator_output(&cptr[0],(cptr[0].lastcval+cptr[0].cval)*cptr[0].mfbi/2,tremval1[i]);
+
+								Bit32s chanval = cptr[0].cval;
+								CHANVAL_OUT
+							}
+						}
+
+						if ((cptr[3].op_state != OF_TYPE_OFF) || (cptr[9].op_state != OF_TYPE_OFF)) {
+							if ((cptr[9].vibrato) && (cptr[9].op_state != OF_TYPE_OFF)) {
+								vibval1 = vibval_var1;
+								for (i=0;i<endsamples;i++)
+									vibval1[i] = (Bit32s)((vib_lut[i]*cptr[9].freq_high/8)*FIXEDPT*VIBFAC);
+							} else vibval1 = vibval_const;
+							if (cptr[9].tremolo) tremval1 = trem_lut;	// tremolo enabled, use table
+							else tremval1 = tremval_const;
+							if (cptr[3].tremolo) tremval2 = trem_lut;	// tremolo enabled, use table
+							else tremval2 = tremval_const;
+
+							// calculate channel output
+							for (i=0;i<endsamples;i++) {
+								operator_advance(&cptr[9],vibval1[i]);
+								opfuncs[cptr[9].op_state](&cptr[9]);
+								operator_output(&cptr[9],0,tremval1[i]);
+
+								operator_advance(&cptr[3],0);
+								opfuncs[cptr[3].op_state](&cptr[3]);
+								operator_output(&cptr[3],cptr[9].cval*FIXEDPT,tremval2[i]);
+
+								Bit32s chanval = cptr[3].cval;
+								CHANVAL_OUT
+							}
+						}
+
+						if (cptr[3+9].op_state != OF_TYPE_OFF) {
+							if (cptr[3+9].tremolo) tremval1 = trem_lut;	// tremolo enabled, use table
+							else tremval1 = tremval_const;
+
+							// calculate channel output
+							for (i=0;i<endsamples;i++) {
+								operator_advance(&cptr[3+9],0);
+								opfuncs[cptr[3+9].op_state](&cptr[3+9]);
+								operator_output(&cptr[3+9],0,tremval1[i]);
+
+								Bit32s chanval = cptr[3+9].cval;
+								CHANVAL_OUT
+							}
+						}
+					} else {
+						// AM-FM-style synthesis (op1[fb] + (op2 * op3 * op4))
+						if (cptr[0].op_state != OF_TYPE_OFF) {
+							if (cptr[0].vibrato) {
+								vibval1 = vibval_var1;
+								for (i=0;i<endsamples;i++)
+									vibval1[i] = (Bit32s)((vib_lut[i]*cptr[0].freq_high/8)*FIXEDPT*VIBFAC);
+							} else vibval1 = vibval_const;
+							if (cptr[0].tremolo) tremval1 = trem_lut;	// tremolo enabled, use table
+							else tremval1 = tremval_const;
+
+							// calculate channel output
+							for (i=0;i<endsamples;i++) {
+								operator_advance(&cptr[0],vibval1[i]);
+								opfuncs[cptr[0].op_state](&cptr[0]);
+								operator_output(&cptr[0],(cptr[0].lastcval+cptr[0].cval)*cptr[0].mfbi/2,tremval1[i]);
+
+								Bit32s chanval = cptr[0].cval;
+								CHANVAL_OUT
+							}
+						}
+
+						if ((cptr[9].op_state != OF_TYPE_OFF) || (cptr[3].op_state != OF_TYPE_OFF) || (cptr[3+9].op_state != OF_TYPE_OFF)) {
+							if ((cptr[9].vibrato) && (cptr[9].op_state != OF_TYPE_OFF)) {
+								vibval1 = vibval_var1;
+								for (i=0;i<endsamples;i++)
+									vibval1[i] = (Bit32s)((vib_lut[i]*cptr[9].freq_high/8)*FIXEDPT*VIBFAC);
+							} else vibval1 = vibval_const;
+							if (cptr[9].tremolo) tremval1 = trem_lut;	// tremolo enabled, use table
+							else tremval1 = tremval_const;
+							if (cptr[3].tremolo) tremval2 = trem_lut;	// tremolo enabled, use table
+							else tremval2 = tremval_const;
+							if (cptr[3+9].tremolo) tremval3 = trem_lut;	// tremolo enabled, use table
+							else tremval3 = tremval_const;
+
+							// calculate channel output
+							for (i=0;i<endsamples;i++) {
+								operator_advance(&cptr[9],vibval1[i]);
+								opfuncs[cptr[9].op_state](&cptr[9]);
+								operator_output(&cptr[9],0,tremval1[i]);
+
+								operator_advance(&cptr[3],0);
+								opfuncs[cptr[3].op_state](&cptr[3]);
+								operator_output(&cptr[3],cptr[9].cval*FIXEDPT,tremval2[i]);
+
+								operator_advance(&cptr[3+9],0);
+								opfuncs[cptr[3+9].op_state](&cptr[3+9]);
+								operator_output(&cptr[3+9],cptr[3].cval*FIXEDPT,tremval3[i]);
+
+								Bit32s chanval = cptr[3+9].cval;
+								CHANVAL_OUT
+							}
+						}
+					}
+					continue;
+				}
+#endif
+				// 2op additive synthesis
+				if ((cptr[9].op_state == OF_TYPE_OFF) && (cptr[0].op_state == OF_TYPE_OFF)) continue;
+				if ((cptr[0].vibrato) && (cptr[0].op_state != OF_TYPE_OFF)) {
+					vibval1 = vibval_var1;
+					for (i=0;i<endsamples;i++)
+						vibval1[i] = (Bit32s)((vib_lut[i]*cptr[0].freq_high/8)*FIXEDPT*VIBFAC);
+				} else vibval1 = vibval_const;
+				if ((cptr[9].vibrato) && (cptr[9].op_state != OF_TYPE_OFF)) {
+					vibval2 = vibval_var2;
+					for (i=0;i<endsamples;i++)
+						vibval2[i] = (Bit32s)((vib_lut[i]*cptr[9].freq_high/8)*FIXEDPT*VIBFAC);
+				} else vibval2 = vibval_const;
+				if (cptr[0].tremolo) tremval1 = trem_lut;	// tremolo enabled, use table
+				else tremval1 = tremval_const;
+				if (cptr[9].tremolo) tremval2 = trem_lut;	// tremolo enabled, use table
+				else tremval2 = tremval_const;
+
+				// calculate channel output
+				for (i=0;i<endsamples;i++) {
+					// carrier1
+					operator_advance(&cptr[0],vibval1[i]);
+					opfuncs[cptr[0].op_state](&cptr[0]);
+					operator_output(&cptr[0],(cptr[0].lastcval+cptr[0].cval)*cptr[0].mfbi/2,tremval1[i]);
+
+					// carrier2
+					operator_advance(&cptr[9],vibval2[i]);
+					opfuncs[cptr[9].op_state](&cptr[9]);
+					operator_output(&cptr[9],0,tremval2[i]);
+
+					Bit32s chanval = cptr[9].cval + cptr[0].cval;
+					CHANVAL_OUT
+				}
+			} else {
+#if defined(OPLTYPE_IS_OPL3)
+				if ((adlibreg[0x105]&1) && cptr->is_4op) {
+					if (adlibreg[ARC_FEEDBACK+k+3]&1) {
+						// FM-AM-style synthesis ((op1[fb] * op2) + (op3 * op4))
+						if ((cptr[0].op_state != OF_TYPE_OFF) || (cptr[9].op_state != OF_TYPE_OFF)) {
+							if ((cptr[0].vibrato) && (cptr[0].op_state != OF_TYPE_OFF)) {
+								vibval1 = vibval_var1;
+								for (i=0;i<endsamples;i++)
+									vibval1[i] = (Bit32s)((vib_lut[i]*cptr[0].freq_high/8)*FIXEDPT*VIBFAC);
+							} else vibval1 = vibval_const;
+							if ((cptr[9].vibrato) && (cptr[9].op_state != OF_TYPE_OFF)) {
+								vibval2 = vibval_var2;
+								for (i=0;i<endsamples;i++)
+									vibval2[i] = (Bit32s)((vib_lut[i]*cptr[9].freq_high/8)*FIXEDPT*VIBFAC);
+							} else vibval2 = vibval_const;
+							if (cptr[0].tremolo) tremval1 = trem_lut;	// tremolo enabled, use table
+							else tremval1 = tremval_const;
+							if (cptr[9].tremolo) tremval2 = trem_lut;	// tremolo enabled, use table
+							else tremval2 = tremval_const;
+
+							// calculate channel output
+							for (i=0;i<endsamples;i++) {
+								operator_advance(&cptr[0],vibval1[i]);
+								opfuncs[cptr[0].op_state](&cptr[0]);
+								operator_output(&cptr[0],(cptr[0].lastcval+cptr[0].cval)*cptr[0].mfbi/2,tremval1[i]);
+
+								operator_advance(&cptr[9],vibval2[i]);
+								opfuncs[cptr[9].op_state](&cptr[9]);
+								operator_output(&cptr[9],cptr[0].cval*FIXEDPT,tremval2[i]);
+
+								Bit32s chanval = cptr[9].cval;
+								CHANVAL_OUT
+							}
+						}
+
+						if ((cptr[3].op_state != OF_TYPE_OFF) || (cptr[3+9].op_state != OF_TYPE_OFF)) {
+							if (cptr[3].tremolo) tremval1 = trem_lut;	// tremolo enabled, use table
+							else tremval1 = tremval_const;
+							if (cptr[3+9].tremolo) tremval2 = trem_lut;	// tremolo enabled, use table
+							else tremval2 = tremval_const;
+
+							// calculate channel output
+							for (i=0;i<endsamples;i++) {
+								operator_advance(&cptr[3],0);
+								opfuncs[cptr[3].op_state](&cptr[3]);
+								operator_output(&cptr[3],0,tremval1[i]);
+
+								operator_advance(&cptr[3+9],0);
+								opfuncs[cptr[3+9].op_state](&cptr[3+9]);
+								operator_output(&cptr[3+9],cptr[3].cval*FIXEDPT,tremval2[i]);
+
+								Bit32s chanval = cptr[3+9].cval;
+								CHANVAL_OUT
+							}
+						}
+
+					} else {
+						// FM-FM-style synthesis (op1[fb] * op2 * op3 * op4)
+						if ((cptr[0].op_state != OF_TYPE_OFF) || (cptr[9].op_state != OF_TYPE_OFF) || 
+							(cptr[3].op_state != OF_TYPE_OFF) || (cptr[3+9].op_state != OF_TYPE_OFF)) {
+							if ((cptr[0].vibrato) && (cptr[0].op_state != OF_TYPE_OFF)) {
+								vibval1 = vibval_var1;
+								for (i=0;i<endsamples;i++)
+									vibval1[i] = (Bit32s)((vib_lut[i]*cptr[0].freq_high/8)*FIXEDPT*VIBFAC);
+							} else vibval1 = vibval_const;
+							if ((cptr[9].vibrato) && (cptr[9].op_state != OF_TYPE_OFF)) {
+								vibval2 = vibval_var2;
+								for (i=0;i<endsamples;i++)
+									vibval2[i] = (Bit32s)((vib_lut[i]*cptr[9].freq_high/8)*FIXEDPT*VIBFAC);
+							} else vibval2 = vibval_const;
+							if (cptr[0].tremolo) tremval1 = trem_lut;	// tremolo enabled, use table
+							else tremval1 = tremval_const;
+							if (cptr[9].tremolo) tremval2 = trem_lut;	// tremolo enabled, use table
+							else tremval2 = tremval_const;
+							if (cptr[3].tremolo) tremval3 = trem_lut;	// tremolo enabled, use table
+							else tremval3 = tremval_const;
+							if (cptr[3+9].tremolo) tremval4 = trem_lut;	// tremolo enabled, use table
+							else tremval4 = tremval_const;
+
+							// calculate channel output
+							for (i=0;i<endsamples;i++) {
+								operator_advance(&cptr[0],vibval1[i]);
+								opfuncs[cptr[0].op_state](&cptr[0]);
+								operator_output(&cptr[0],(cptr[0].lastcval+cptr[0].cval)*cptr[0].mfbi/2,tremval1[i]);
+
+								operator_advance(&cptr[9],vibval2[i]);
+								opfuncs[cptr[9].op_state](&cptr[9]);
+								operator_output(&cptr[9],cptr[0].cval*FIXEDPT,tremval2[i]);
+
+								operator_advance(&cptr[3],0);
+								opfuncs[cptr[3].op_state](&cptr[3]);
+								operator_output(&cptr[3],cptr[9].cval*FIXEDPT,tremval3[i]);
+
+								operator_advance(&cptr[3+9],0);
+								opfuncs[cptr[3+9].op_state](&cptr[3+9]);
+								operator_output(&cptr[3+9],cptr[3].cval*FIXEDPT,tremval4[i]);
+
+								Bit32s chanval = cptr[3+9].cval;
+								CHANVAL_OUT
+							}
+						}
+					}
+					continue;
+				}
+#endif
+				// 2op frequency modulation
+				if ((cptr[9].op_state == OF_TYPE_OFF) && (cptr[0].op_state == OF_TYPE_OFF)) continue;
+				if ((cptr[0].vibrato) && (cptr[0].op_state != OF_TYPE_OFF)) {
+					vibval1 = vibval_var1;
+					for (i=0;i<endsamples;i++)
+						vibval1[i] = (Bit32s)((vib_lut[i]*cptr[0].freq_high/8)*FIXEDPT*VIBFAC);
+				} else vibval1 = vibval_const;
+				if ((cptr[9].vibrato) && (cptr[9].op_state != OF_TYPE_OFF)) {
+					vibval2 = vibval_var2;
+					for (i=0;i<endsamples;i++)
+						vibval2[i] = (Bit32s)((vib_lut[i]*cptr[9].freq_high/8)*FIXEDPT*VIBFAC);
+				} else vibval2 = vibval_const;
+				if (cptr[0].tremolo) tremval1 = trem_lut;	// tremolo enabled, use table
+				else tremval1 = tremval_const;
+				if (cptr[9].tremolo) tremval2 = trem_lut;	// tremolo enabled, use table
+				else tremval2 = tremval_const;
+
+				// calculate channel output
+				for (i=0;i<endsamples;i++) {
+					// modulator
+					operator_advance(&cptr[0],vibval1[i]);
+					opfuncs[cptr[0].op_state](&cptr[0]);
+					operator_output(&cptr[0],(cptr[0].lastcval+cptr[0].cval)*cptr[0].mfbi/2,tremval1[i]);
+
+					// carrier
+					operator_advance(&cptr[9],vibval2[i]);
+					opfuncs[cptr[9].op_state](&cptr[9]);
+					operator_output(&cptr[9],cptr[0].cval*FIXEDPT,tremval2[i]);
+
+					Bit32s chanval = cptr[9].cval;
+					CHANVAL_OUT
+				}
+			}
+		}
+
+#if defined(OPLTYPE_IS_OPL3)
+		if (adlibreg[0x105]&1) {
+			// convert to 16bit samples (stereo)
+			for (i=0;i<endsamples;i++) {
+				clipit16(outbufl[i],sndptr++);
+				clipit16(outbufr[i],sndptr++);
+			}
+		} else {
+			// convert to 16bit samples (mono)
+			for (i=0;i<endsamples;i++) {
+				clipit16(outbufl[i],sndptr++);
+				clipit16(outbufl[i],sndptr++);
+			}
+		}
+#else
+		// convert to 16bit samples
+		for (i=0;i<endsamples;i++)
+			clipit16(outbufl[i],sndptr++);
+#endif
+
+	}
+}
diff --git a/sound/softsynth/opl/opl.h b/sound/softsynth/opl/opl.h
new file mode 100644
index 0000000000..4a04f9a0b7
--- /dev/null
+++ b/sound/softsynth/opl/opl.h
@@ -0,0 +1,197 @@
+/*
+ *  Copyright (C) 2002-2009  The DOSBox Team
+ *  OPL2/OPL3 emulation library
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2.1 of the License, or (at your option) any later version.
+ * 
+ *  This library 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
+ *  Lesser General Public License for more details.
+ * 
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, write to the Free Software
+ *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+
+/*
+ * Originally based on ADLIBEMU.C, an AdLib/OPL2 emulation library by Ken Silverman
+ * Copyright (C) 1998-2001 Ken Silverman
+ * Ken Silverman's official web site: "http://www.advsys.net/ken"
+ */
+
+
+#define fltype double
+
+/*
+	define Bits, Bitu, Bit32s, Bit32u, Bit16s, Bit16u, Bit8s, Bit8u here
+*/
+
+typedef uint	Bitu;
+typedef int		Bits;
+typedef uint32	Bit32u;
+typedef int32	Bit32s;
+typedef uint16	Bit16u;
+typedef int16	Bit16s;
+typedef uint8	Bit8u;
+typedef int8	Bit8s;
+
+#undef NUM_CHANNELS
+#if defined(OPLTYPE_IS_OPL3)
+#define NUM_CHANNELS	18
+#else
+#define NUM_CHANNELS	9
+#endif
+
+#define MAXOPERATORS	(NUM_CHANNELS*2)
+
+
+#define FL05	((fltype)0.5)
+#define FL2		((fltype)2.0)
+
+#ifdef PI
+#undef PI
+#endif
+
+#define PI		((fltype)3.1415926535897932384626433832795)
+
+
+#define FIXEDPT			0x10000		// fixed-point calculations using 16+16
+#define FIXEDPT_LFO		0x1000000	// fixed-point calculations using 8+24
+
+#define WAVEPREC		1024		// waveform precision (10 bits)
+
+#define INTFREQU		((fltype)(14318180.0 / 288.0))		// clocking of the chip
+
+
+#define OF_TYPE_ATT			0
+#define OF_TYPE_DEC			1
+#define OF_TYPE_REL			2
+#define OF_TYPE_SUS			3
+#define OF_TYPE_SUS_NOKEEP	4
+#define OF_TYPE_OFF			5
+
+#define ARC_CONTROL			0x00
+#define ARC_TVS_KSR_MUL		0x20
+#define ARC_KSL_OUTLEV		0x40
+#define ARC_ATTR_DECR		0x60
+#define ARC_SUSL_RELR		0x80
+#define ARC_FREQ_NUM		0xa0
+#define ARC_KON_BNUM		0xb0
+#define ARC_PERC_MODE		0xbd
+#define ARC_FEEDBACK		0xc0
+#define ARC_WAVE_SEL		0xe0
+
+#define ARC_SECONDSET		0x100	// second operator set for OPL3
+
+
+#define OP_ACT_OFF			0x00
+#define OP_ACT_NORMAL		0x01	// regular channel activated (bitmasked)
+#define OP_ACT_PERC			0x02	// percussion channel activated (bitmasked)
+
+#define BLOCKBUF_SIZE		512
+
+
+// vibrato constants
+#define VIBTAB_SIZE			8
+#define VIBFAC				70/50000		// no braces, integer mul/div
+
+// tremolo constants and table
+#define TREMTAB_SIZE		53
+#define TREM_FREQ			((fltype)(3.7))			// tremolo at 3.7hz
+
+
+/* operator struct definition
+     For OPL2 all 9 channels consist of two operators each, carrier and modulator.
+     Channel x has operators x as modulator and operators (9+x) as carrier.
+     For OPL3 all 18 channels consist either of two operators (2op mode) or four
+     operators (4op mode) which is determined through register4 of the second
+     adlib register set.
+     Only the channels 0,1,2 (first set) and 9,10,11 (second set) can act as
+     4op channels. The two additional operators for a channel y come from the
+     2op channel y+3 so the operatorss y, (9+y), y+3, (9+y)+3 make up a 4op
+     channel.
+*/
+typedef struct operator_struct {
+	Bit32s cval, lastcval;			// current output/last output (used for feedback)
+	Bit32u tcount, wfpos, tinc;		// time (position in waveform) and time increment
+	fltype amp, step_amp;			// and amplification (envelope)
+	fltype vol;						// volume
+	fltype sustain_level;			// sustain level
+	Bit32s mfbi;					// feedback amount
+	fltype a0, a1, a2, a3;			// attack rate function coefficients
+	fltype decaymul, releasemul;	// decay/release rate functions
+	Bit32u op_state;				// current state of operator (attack/decay/sustain/release/off)
+	Bit32u toff;
+	Bit32s freq_high;				// highest three bits of the frequency, used for vibrato calculations
+	Bit16s* cur_wform;				// start of selected waveform
+	Bit32u cur_wmask;				// mask for selected waveform
+	Bit32u act_state;				// activity state (regular, percussion)
+	bool sus_keep;					// keep sustain level when decay finished
+	bool vibrato,tremolo;			// vibrato/tremolo enable bits
+	
+	// variables used to provide non-continuous envelopes
+	Bit32u generator_pos;			// for non-standard sample rates we need to determine how many samples have passed
+	Bits cur_env_step;				// current (standardized) sample position
+	Bits env_step_a,env_step_d,env_step_r;	// number of std samples of one step (for attack/decay/release mode)
+	Bit8u step_skip_pos;			// position of 8-cyclic step skipping (always 2^x to check against mask)
+	Bits env_step_skip_a;			// bitmask that determines if a step is skipped (respective bit is zero then)
+
+#if defined(OPLTYPE_IS_OPL3)
+	bool is_4op,is_4op_attached;	// base of a 4op channel/part of a 4op channel
+	Bit32s left_pan,right_pan;		// opl3 stereo panning amount
+#endif
+} op_type;
+
+// per-chip variables
+Bitu chip_num;
+op_type op[MAXOPERATORS];
+
+Bits int_samplerate;
+	
+Bit8u status;
+Bit32u index;
+#if defined(OPLTYPE_IS_OPL3)
+Bit8u adlibreg[512];	// adlib register set (including second set)
+Bit8u wave_sel[44];		// waveform selection
+#else
+Bit8u adlibreg[256];	// adlib register set
+Bit8u wave_sel[22];		// waveform selection
+#endif
+
+
+// vibrato/tremolo increment/counter
+Bit32u vibtab_pos;
+Bit32u vibtab_add;
+Bit32u tremtab_pos;
+Bit32u tremtab_add;
+
+
+// enable an operator
+void enable_operator(Bitu regbase, op_type* op_pt);
+
+// functions to change parameters of an operator
+void change_frequency(Bitu chanbase, Bitu regbase, op_type* op_pt);
+
+void change_attackrate(Bitu regbase, op_type* op_pt);
+void change_decayrate(Bitu regbase, op_type* op_pt);
+void change_releaserate(Bitu regbase, op_type* op_pt);
+void change_sustainlevel(Bitu regbase, op_type* op_pt);
+void change_waveform(Bitu regbase, op_type* op_pt);
+void change_keepsustain(Bitu regbase, op_type* op_pt);
+void change_vibrato(Bitu regbase, op_type* op_pt);
+void change_feedback(Bitu chanbase, op_type* op_pt);
+
+// general functions
+void adlib_init(Bit32u samplerate);
+void adlib_write(Bitu idx, Bit8u val);
+void adlib_getsample(Bit16s* sndptr, Bits numsamples);
+
+Bitu adlib_reg_read(Bitu port);
+void adlib_write_index(Bitu port, Bit8u val);
+
+static Bit32u generator_add;	// should be a chip parameter