Added MAME OPL2 emulator

10 files changed, 2042 insertions, 2 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index faaab65..7ce1e91 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -212,6 +212,7 @@ option(USE_NUKED_EMULATOR   "Use Nuked OPL3 emulator (most accurate, powerful)"
 option(USE_OPAL_EMULATOR    "Use Opal emulator (inaccurate)" ${DEFAULT_HEAVY_EMULATORS})
 option(USE_JAVA_EMULATOR    "Use JavaOPL emulator" ${DEFAULT_HEAVY_EMULATORS})
 option(USE_ESFMU_EMULATOR   "Use ESFMu emulator (Based on Nuked OPL3, powerful)" ${DEFAULT_HEAVY_EMULATORS})
+option(USE_MAME_EMULATOR    "Use MAME OPL2 emulator" ${DEFAULT_HEAVY_EMULATORS})
 if(COMPILER_SUPPORTS_CXX14)
     option(USE_YMFM_EMULATOR    "Use YMFM emulator (requires C++14 support)" ON)
 endif()
@@ -332,6 +333,18 @@ function(handle_options targetLib)
             target_compile_definitions(${targetLib} PUBLIC ADLMIDI_DISABLE_ESFMU_EMULATOR)
         endif()
 
+        if(USE_MAME_EMULATOR)
+            set(HAS_EMULATOR TRUE)
+            target_sources(${targetLib} PRIVATE
+                ${libADLMIDI_SOURCE_DIR}/src/chips/mame_opl2.cpp
+                ${libADLMIDI_SOURCE_DIR}/src/chips/mame_opl2.h
+                ${libADLMIDI_SOURCE_DIR}/src/chips/mame/opl.h
+                ${libADLMIDI_SOURCE_DIR}/src/chips/mame/mame_fmopl.cpp
+            )
+        else()
+            target_compile_definitions(${targetLib} PUBLIC ADLMIDI_DISABLE_MAME_OPL2_EMULATOR)
+        endif()
+
         if(USE_YMFM_EMULATOR)
             set(YMFM_SOURCES
                 ${libADLMIDI_SOURCE_DIR}/src/chips/ymfm_opl2.cpp
@@ -632,6 +645,7 @@ message("USE_NUKED_EMULATOR       = ${USE_NUKED_EMULATOR}")
 message("USE_OPAL_EMULATOR        = ${USE_OPAL_EMULATOR}")
 message("USE_JAVA_EMULATOR        = ${USE_JAVA_EMULATOR}")
 message("USE_ESFMU_EMULATOR       = ${USE_ESFMU_EMULATOR}")
+message("USE_MAME_EMULATOR        = ${USE_MAME_EMULATOR}")
 if(COMPILER_SUPPORTS_CXX14)
     message("USE_YMFM_EMULATOR        = ${USE_YMFM_EMULATOR}")
 endif()
diff --git a/include/adlmidi.h b/include/adlmidi.h
index 4b1dc24..13e39d9 100644
--- a/include/adlmidi.h
+++ b/include/adlmidi.h
@@ -707,6 +707,8 @@ enum ADL_Emulator
     ADLMIDI_EMU_JAVA,
     /*! ESFMu */
     ADLMIDI_EMU_ESFMu,
+    /*! MAME OPL2 */
+    ADLMIDI_EMU_MAME_OPL2,
     /*! YMFM OPL2 */
     ADLMIDI_EMU_YMFM_OPL2,
     /*! YMFM OPL3 */
diff --git a/src/adlmidi_opl3.cpp b/src/adlmidi_opl3.cpp
index 72f2bbb..3ad0d32 100644
--- a/src/adlmidi_opl3.cpp
+++ b/src/adlmidi_opl3.cpp
@@ -66,6 +66,11 @@ static const unsigned OPLBase = 0x388;
 #       include "chips/esfmu_opl3.h"
 #   endif
 
+// MAME OPL2 emulator
+#   ifndef ADLMIDI_DISABLE_MAME_OPL2_EMULATOR
+#       include "chips/mame_opl2.h"
+#   endif
+
 // YMFM emulators
 #   ifndef ADLMIDI_DISABLE_YMFM_EMULATOR
 #       include "chips/ymfm_opl2.h"
@@ -100,6 +105,10 @@ static const unsigned adl_emulatorSupport = 0
     | (1u << ADLMIDI_EMU_JAVA)
 #   endif
 
+#   ifndef ADLMIDI_DISABLE_MAME_OPL2_EMULATOR
+    | (1u << ADLMIDI_EMU_MAME_OPL2)
+#   endif
+
 #   ifndef ADLMIDI_DISABLE_YMFM_EMULATOR
     | (1u << ADLMIDI_EMU_YMFM_OPL2)
     | (1u << ADLMIDI_EMU_YMFM_OPL3)
@@ -1837,6 +1846,11 @@ void OPL3::reset(int emulator, unsigned long PCM_RATE, void *audioTickHandler)
             chip = new ESFMuOPL3;
             break;
 #endif
+#ifndef ADLMIDI_DISABLE_MAME_OPL2_EMULATOR
+        case ADLMIDI_EMU_MAME_OPL2:
+            chip = new MameOPL2;
+            break;
+#endif
 #ifndef ADLMIDI_DISABLE_YMFM_EMULATOR
         case ADLMIDI_EMU_YMFM_OPL2:
             chip = new YmFmOPL2;
@@ -1875,12 +1889,14 @@ void OPL3::initChip(size_t chip)
         0x001, 32, 0x105, 1,          // Enable wave, OPL3 extensions
         0x08, 0                       // CSW/Note Sel
     };
+    static const size_t data_opl3_size = sizeof(data_opl3) / sizeof(uint16_t);
 
     static const uint16_t data_opl2[] =
     {
         0x004, 96, 0x004, 128,          // Pulse timer
         0x001, 32                       // Enable wave
     };
+    static const size_t data_opl2_size = sizeof(data_opl2) / sizeof(uint16_t);
 
     // Report does emulator/interface supports full-panning stereo or not
     if(chip == 0)
@@ -1907,12 +1923,12 @@ void OPL3::initChip(size_t chip)
 
     if(m_currentChipType == OPLChipBase::CHIPTYPE_OPL2)
     {
-        for(size_t a = 0; a < sizeof(data_opl2) / sizeof(*data_opl2); a += 2)
+        for(size_t a = 0; a < data_opl2_size; a += 2)
             writeRegI(chip, data_opl2[a], (data_opl2[a + 1]));
     }
     else
     {
-        for(size_t a = 0; a < sizeof(data_opl3) / sizeof(*data_opl3); a += 2)
+        for(size_t a = 0; a < data_opl3_size; a += 2)
             writeRegI(chip, data_opl3[a], (data_opl3[a + 1]));
     }
 }
diff --git a/src/chips/mame/mame_fmopl.cpp b/src/chips/mame/mame_fmopl.cpp
new file mode 100644
index 0000000..c1dbada
--- /dev/null
+++ b/src/chips/mame/mame_fmopl.cpp
@@ -0,0 +1,1852 @@
+// license:GPL-2.0+
+// copyright-holders:Jarek Burczynski,Tatsuyuki Satoh
+/*
+
+This file is based on fmopl.c from MAME. The non-YM3816 parts have been
+ripped out in the interest of making this simpler, since Doom music doesn't
+need them. I also made it render the sound a voice at a time instead of a
+sample at a time, so unused voices don't waste time being calculated. If all
+voices are playing, it's not much difference, but it does offer a big
+improvement when only a few voices are playing.
+
+
+
+**
+** File: fmopl.c - software implementation of FM sound generator
+**                                            types OPL and OPL2
+**
+** Copyright Jarek Burczynski (bujar at mame dot net)
+** Copyright Tatsuyuki Satoh , MultiArcadeMachineEmulator development
+**
+** Version 0.72
+**
+
+Revision History:
+
+04-08-2003 Jarek Burczynski:
+ - removed BFRDY hack. BFRDY is busy flag, and it should be 0 only when the chip
+   handles memory read/write or during the adpcm synthesis when the chip
+   requests another byte of ADPCM data.
+
+24-07-2003 Jarek Burczynski:
+ - added a small hack for Y8950 status BFRDY flag (bit 3 should be set after
+   some (unknown) delay). Right now it's always set.
+
+14-06-2003 Jarek Burczynski:
+ - implemented all of the status register flags in Y8950 emulation
+ - renamed y8950_set_delta_t_memory() parameters from _rom_ to _mem_ since
+   they can be either RAM or ROM
+
+08-10-2002 Jarek Burczynski (thanks to Dox for the YM3526 chip)
+ - corrected ym3526_read() to always set bit 2 and bit 1
+   to HIGH state - identical to ym3812_read (verified on real YM3526)
+
+04-28-2002 Jarek Burczynski:
+ - binary exact Envelope Generator (verified on real YM3812);
+   compared to YM2151: the EG clock is equal to internal_clock,
+   rates are 2 times slower and volume resolution is one bit less
+ - modified interface functions (they no longer return pointer -
+   that's internal to the emulator now):
+    - new wrapper functions for OPLCreate: ym3526_init(), ym3812_init() and y8950_init()
+ - corrected 'off by one' error in feedback calculations (when feedback is off)
+ - enabled waveform usage (credit goes to Vlad Romascanu and zazzal22)
+ - speeded up noise generator calculations (Nicola Salmoria)
+
+03-24-2002 Jarek Burczynski (thanks to Dox for the YM3812 chip)
+ Complete rewrite (all verified on real YM3812):
+ - corrected sin_tab and tl_tab data
+ - corrected operator output calculations
+ - corrected waveform_select_enable register;
+   simply: ignore all writes to waveform_select register when
+   waveform_select_enable == 0 and do not change the waveform previously selected.
+ - corrected KSR handling
+ - corrected Envelope Generator: attack shape, Sustain mode and
+   Percussive/Non-percussive modes handling
+ - Envelope Generator rates are two times slower now
+ - LFO amplitude (tremolo) and phase modulation (vibrato)
+ - rhythm sounds phase generation
+ - white noise generator (big thanks to Olivier Galibert for mentioning Berlekamp-Massey algorithm)
+ - corrected key on/off handling (the 'key' signal is ORed from three sources: FM, rhythm and CSM)
+ - funky details (like ignoring output of operator 1 in BD rhythm sound when connect == 1)
+
+12-28-2001 Acho A. Tang
+ - reflected Delta-T EOS status on Y8950 status port.
+ - fixed subscription range of attack/decay tables
+
+
+    To do:
+        add delay before key off in CSM mode (see CSMKeyControll)
+        verify volume of the FM part on the Y8950
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+#include <stdint.h>
+#include <string>
+//#include "driver.h"		/* use M.A.M.E. */
+#include "opl.h"
+
+/* compiler dependence */
+#ifndef OSD_CPU_H
+#define OSD_CPU_H
+#endif
+
+#ifndef PI
+#define PI 3.14159265358979323846
+#endif
+
+#ifdef _MSC_VER
+#pragma warning (disable: 4244)
+#endif
+
+
+#define FREQ_SH         16  /* 16.16 fixed point (frequency calculations) */
+#define EG_SH           16  /* 16.16 fixed point (EG timing)              */
+#define LFO_SH          24  /*  8.24 fixed point (LFO calculations)       */
+#define TIMER_SH        16  /* 16.16 fixed point (timers calculations)    */
+
+#define FREQ_MASK       ((1<<FREQ_SH)-1)
+
+/* envelope output entries */
+#define ENV_BITS        10
+#define ENV_LEN         (1<<ENV_BITS)
+#define ENV_STEP        (128.0/ENV_LEN)
+
+#define MAX_ATT_INDEX   ((1<<(ENV_BITS-1))-1) /*511*/
+#define MIN_ATT_INDEX   (0)
+
+/* sinwave entries */
+#define SIN_BITS        10
+#define SIN_LEN         (1<<SIN_BITS)
+#define SIN_MASK        (SIN_LEN-1)
+
+#define TL_RES_LEN      (256)   /* 8 bits addressing (real chip) */
+
+
+
+/* register number to channel number , slot offset */
+#define SLOT1 0
+#define SLOT2 1
+
+/* Envelope Generator phases */
+
+#define EG_ATT          4
+#define EG_DEC          3
+#define EG_SUS          2
+#define EG_REL          1
+#define EG_OFF          0
+
+
+#define OPL_CLOCK		3579545						// master clock (Hz)
+#define OPL_RATE		49716						// sampling rate (Hz)
+#define OPL_TIMERBASE	(OPL_CLOCK / 72.0)			// Timer base time (==sampling time)
+#define OPL_FREQBASE	(OPL_TIMERBASE / OPL_RATE)	// frequency base
+
+
+/* Saving is necessary for member of the 'R' mark for suspend/resume */
+
+struct OPL_SLOT
+{
+	uint32_t  ar;         /* attack rate: AR<<2           */
+	uint32_t  dr;         /* decay rate:  DR<<2           */
+	uint32_t  rr;         /* release rate:RR<<2           */
+	uint8_t   KSR;        /* key scale rate               */
+	uint8_t   ksl;        /* keyscale level               */
+	uint8_t   ksr;        /* key scale rate: kcode>>KSR   */
+	uint8_t   mul;        /* multiple: mul_tab[ML]        */
+
+	/* Phase Generator */
+	uint32_t  Cnt;        /* frequency counter            */
+	uint32_t  Incr;       /* frequency counter step       */
+	uint8_t   FB;         /* feedback shift value         */
+	int32_t   *connect1;  /* slot1 output pointer         */
+	int32_t   op1_out[2]; /* slot1 output for feedback    */
+	uint8_t   CON;        /* connection (algorithm) type  */
+
+	/* Envelope Generator */
+	uint8_t   eg_type;    /* percussive/non-percussive mode */
+	uint8_t   state;      /* phase type                   */
+	uint32_t  TL;         /* total level: TL << 2         */
+	int32_t   TLL;        /* adjusted now TL              */
+	int32_t   volume;     /* envelope counter             */
+	uint32_t  sl;         /* sustain level: sl_tab[SL]    */
+	uint8_t   eg_sh_ar;   /* (attack state)               */
+	uint8_t   eg_sel_ar;  /* (attack state)               */
+	uint8_t   eg_sh_dr;   /* (decay state)                */
+	uint8_t   eg_sel_dr;  /* (decay state)                */
+	uint8_t   eg_sh_rr;   /* (release state)              */
+	uint8_t   eg_sel_rr;  /* (release state)              */
+	uint32_t  key;        /* 0 = KEY OFF, >0 = KEY ON     */
+
+	/* LFO */
+	uint32_t  AMmask;     /* LFO Amplitude Modulation enable mask */
+	uint8_t   vib;        /* LFO Phase Modulation enable flag (active high)*/
+
+	/* waveform select */
+	uint16_t  wavetable;
+};
+
+struct OPL_CH
+{
+	OPL_SLOT SLOT[2];
+	/* phase generator state */
+	uint32_t  block_fnum; /* block+fnum                   */
+	uint32_t  fc;         /* Freq. Increment base         */
+	uint32_t  ksl_base;   /* KeyScaleLevel Base step      */
+	uint8_t   kcode;      /* key code (for key scaling)   */
+	float	LeftVol;	/* volumes for stereo panning	*/
+	float	RightVol;
+};
+
+/* OPL state */
+struct FM_OPL
+{
+	/* FM channel slots */
+	OPL_CH  P_CH[9];                /* OPL/OPL2 chips have 9 channels*/
+
+	uint32_t  eg_cnt;                 /* global envelope generator counter    */
+	uint32_t  eg_timer;               /* global envelope generator counter works at frequency = chipclock/72 */
+	uint32_t  eg_timer_add;           /* step of eg_timer                     */
+	uint32_t  eg_timer_overflow;      /* envelope generator timer overflows every 1 sample (on real chip) */
+
+	uint8_t   rhythm;                 /* Rhythm mode                  */
+
+	uint32_t  fn_tab[1024];           /* fnumber->increment counter   */
+
+	/* LFO */
+
+	uint8_t   lfo_am_depth;
+	uint8_t   lfo_pm_depth_range;
+	uint32_t  lfo_am_cnt;
+	uint32_t  lfo_am_inc;
+	uint32_t  lfo_pm_cnt;
+	uint32_t  lfo_pm_inc;
+
+	uint32_t  noise_rng;              /* 23 bit noise shift register  */
+	uint32_t  noise_p;                /* current noise 'phase'        */
+	uint32_t  noise_f;                /* current noise period         */
+
+	uint8_t   wavesel;                /* waveform select enable flag  */
+
+	int		T[2];					/* timer counters				*/
+	uint8_t   st[2];                  /* timer enable                 */
+
+
+	uint8_t address;                  /* address register             */
+	uint8_t status;                   /* status flag                  */
+	uint8_t statusmask;               /* status mask                  */
+	uint8_t mode;                     /* Reg.08 : CSM,notesel,etc.    */
+
+	bool IsStereo;					/* Write stereo output			*/
+};
+
+
+
+/* mapping of register number (offset) to slot number used by the emulator */
+static const int slot_array[32]=
+{
+	 0, 2, 4, 1, 3, 5,-1,-1,
+	 6, 8,10, 7, 9,11,-1,-1,
+	12,14,16,13,15,17,-1,-1,
+	-1,-1,-1,-1,-1,-1,-1,-1
+};
+
+/* key scale level */
+/* table is 3dB/octave , DV converts this into 6dB/octave */
+/* 0.1875 is bit 0 weight of the envelope counter (volume) expressed in the 'decibel' scale */
+#define DV (0.1875/2.0)
+static const uint32_t ksl_tab[8*16]=
+{
+	/* OCT 0 */
+	 uint32_t(0.000/DV), uint32_t(0.000/DV), uint32_t(0.000/DV), uint32_t(0.000/DV),
+	 uint32_t(0.000/DV), uint32_t(0.000/DV), uint32_t(0.000/DV), uint32_t(0.000/DV),
+	 uint32_t(0.000/DV), uint32_t(0.000/DV), uint32_t(0.000/DV), uint32_t(0.000/DV),
+	 uint32_t(0.000/DV), uint32_t(0.000/DV), uint32_t(0.000/DV), uint32_t(0.000/DV),
+	/* OCT 1 */
+	 uint32_t(0.000/DV), uint32_t(0.000/DV), uint32_t(0.000/DV), uint32_t(0.000/DV),
+	 uint32_t(0.000/DV), uint32_t(0.000/DV), uint32_t(0.000/DV), uint32_t(0.000/DV),
+	 uint32_t(0.000/DV), uint32_t(0.750/DV), uint32_t(1.125/DV), uint32_t(1.500/DV),
+	 uint32_t(1.875/DV), uint32_t(2.250/DV), uint32_t(2.625/DV), uint32_t(3.000/DV),
+	/* OCT 2 */
+	 uint32_t(0.000/DV), uint32_t(0.000/DV), uint32_t(0.000/DV), uint32_t(0.000/DV),
+	 uint32_t(0.000/DV), uint32_t(1.125/DV), uint32_t(1.875/DV), uint32_t(2.625/DV),
+	 uint32_t(3.000/DV), uint32_t(3.750/DV), uint32_t(4.125/DV), uint32_t(4.500/DV),
+	 uint32_t(4.875/DV), uint32_t(5.250/DV), uint32_t(5.625/DV), uint32_t(6.000/DV),
+	/* OCT 3 */
+	 uint32_t(0.000/DV), uint32_t(0.000/DV), uint32_t(0.000/DV), uint32_t(1.875/DV),
+	 uint32_t(3.000/DV), uint32_t(4.125/DV), uint32_t(4.875/DV), uint32_t(5.625/DV),
+	 uint32_t(6.000/DV), uint32_t(6.750/DV), uint32_t(7.125/DV), uint32_t(7.500/DV),
+	 uint32_t(7.875/DV), uint32_t(8.250/DV), uint32_t(8.625/DV), uint32_t(9.000/DV),
+	/* OCT 4 */
+	 uint32_t(0.000/DV), uint32_t(0.000/DV), uint32_t(3.000/DV), uint32_t(4.875/DV),
+	 uint32_t(6.000/DV), uint32_t(7.125/DV), uint32_t(7.875/DV), uint32_t(8.625/DV),
+	 uint32_t(9.000/DV), uint32_t(9.750/DV),uint32_t(10.125/DV),uint32_t(10.500/DV),
+	uint32_t(10.875/DV),uint32_t(11.250/DV),uint32_t(11.625/DV),uint32_t(12.000/DV),
+	/* OCT 5 */
+	 uint32_t(0.000/DV), uint32_t(3.000/DV), uint32_t(6.000/DV), uint32_t(7.875/DV),
+	 uint32_t(9.000/DV),uint32_t(10.125/DV),uint32_t(10.875/DV),uint32_t(11.625/DV),
+	uint32_t(12.000/DV),uint32_t(12.750/DV),uint32_t(13.125/DV),uint32_t(13.500/DV),
+	uint32_t(13.875/DV),uint32_t(14.250/DV),uint32_t(14.625/DV),uint32_t(15.000/DV),
+	/* OCT 6 */
+	 uint32_t(0.000/DV), uint32_t(6.000/DV), uint32_t(9.000/DV),uint32_t(10.875/DV),
+	uint32_t(12.000/DV),uint32_t(13.125/DV),uint32_t(13.875/DV),uint32_t(14.625/DV),
+	uint32_t(15.000/DV),uint32_t(15.750/DV),uint32_t(16.125/DV),uint32_t(16.500/DV),
+	uint32_t(16.875/DV),uint32_t(17.250/DV),uint32_t(17.625/DV),uint32_t(18.000/DV),
+	/* OCT 7 */
+	 uint32_t(0.000/DV), uint32_t(9.000/DV),uint32_t(12.000/DV),uint32_t(13.875/DV),
+	uint32_t(15.000/DV),uint32_t(16.125/DV),uint32_t(16.875/DV),uint32_t(17.625/DV),
+	uint32_t(18.000/DV),uint32_t(18.750/DV),uint32_t(19.125/DV),uint32_t(19.500/DV),
+	uint32_t(19.875/DV),uint32_t(20.250/DV),uint32_t(20.625/DV),uint32_t(21.000/DV)
+};
+#undef DV
+
+/* 0 / 3.0 / 1.5 / 6.0 dB/OCT */
+static const uint32_t ksl_shift[4] = { 31, 1, 2, 0 };
+
+
+/* sustain level table (3dB per step) */
+/* 0 - 15: 0, 3, 6, 9,12,15,18,21,24,27,30,33,36,39,42,93 (dB)*/
+#define SC(db) (uint32_t) ( db * (2.0/ENV_STEP) )
+static const uint32_t sl_tab[16]={
+	SC( 0),SC( 1),SC( 2),SC(3 ),SC(4 ),SC(5 ),SC(6 ),SC( 7),
+	SC( 8),SC( 9),SC(10),SC(11),SC(12),SC(13),SC(14),SC(31)
+};
+#undef SC
+
+
+#define RATE_STEPS (8)
+static const unsigned char eg_inc[15*RATE_STEPS]={
+/*cycle:0 1  2 3  4 5  6 7*/
+
+/* 0 */ 0,1, 0,1, 0,1, 0,1, /* rates 00..12 0 (increment by 0 or 1) */
+/* 1 */ 0,1, 0,1, 1,1, 0,1, /* rates 00..12 1 */
+/* 2 */ 0,1, 1,1, 0,1, 1,1, /* rates 00..12 2 */
+/* 3 */ 0,1, 1,1, 1,1, 1,1, /* rates 00..12 3 */
+
+/* 4 */ 1,1, 1,1, 1,1, 1,1, /* rate 13 0 (increment by 1) */
+/* 5 */ 1,1, 1,2, 1,1, 1,2, /* rate 13 1 */
+/* 6 */ 1,2, 1,2, 1,2, 1,2, /* rate 13 2 */
+/* 7 */ 1,2, 2,2, 1,2, 2,2, /* rate 13 3 */
+
+/* 8 */ 2,2, 2,2, 2,2, 2,2, /* rate 14 0 (increment by 2) */
+/* 9 */ 2,2, 2,4, 2,2, 2,4, /* rate 14 1 */
+/*10 */ 2,4, 2,4, 2,4, 2,4, /* rate 14 2 */
+/*11 */ 2,4, 4,4, 2,4, 4,4, /* rate 14 3 */
+
+/*12 */ 4,4, 4,4, 4,4, 4,4, /* rates 15 0, 15 1, 15 2, 15 3 (increment by 4) */
+/*13 */ 8,8, 8,8, 8,8, 8,8, /* rates 15 2, 15 3 for attack */
+/*14 */ 0,0, 0,0, 0,0, 0,0, /* infinity rates for attack and decay(s) */
+};
+
+
+#define O(a) (a*RATE_STEPS)
+
+/*note that there is no O(13) in this table - it's directly in the code */
+static const unsigned char eg_rate_select[16+64+16]={   /* Envelope Generator rates (16 + 64 rates + 16 RKS) */
+/* 16 infinite time rates */
+O(14),O(14),O(14),O(14),O(14),O(14),O(14),O(14),
+O(14),O(14),O(14),O(14),O(14),O(14),O(14),O(14),
+
+/* rates 00-12 */
+O( 0),O( 1),O( 2),O( 3),
+O( 0),O( 1),O( 2),O( 3),
+O( 0),O( 1),O( 2),O( 3),
+O( 0),O( 1),O( 2),O( 3),
+O( 0),O( 1),O( 2),O( 3),
+O( 0),O( 1),O( 2),O( 3),
+O( 0),O( 1),O( 2),O( 3),
+O( 0),O( 1),O( 2),O( 3),
+O( 0),O( 1),O( 2),O( 3),
+O( 0),O( 1),O( 2),O( 3),
+O( 0),O( 1),O( 2),O( 3),
+O( 0),O( 1),O( 2),O( 3),
+O( 0),O( 1),O( 2),O( 3),
+
+/* rate 13 */
+O( 4),O( 5),O( 6),O( 7),
+
+/* rate 14 */
+O( 8),O( 9),O(10),O(11),
+
+/* rate 15 */
+O(12),O(12),O(12),O(12),
+
+/* 16 dummy rates (same as 15 3) */
+O(12),O(12),O(12),O(12),O(12),O(12),O(12),O(12),
+O(12),O(12),O(12),O(12),O(12),O(12),O(12),O(12),
+
+};
+#undef O
+
+/*rate  0,    1,    2,    3,   4,   5,   6,  7,  8,  9,  10, 11, 12, 13, 14, 15 */
+/*shift 12,   11,   10,   9,   8,   7,   6,  5,  4,  3,  2,  1,  0,  0,  0,  0  */
+/*mask  4095, 2047, 1023, 511, 255, 127, 63, 31, 15, 7,  3,  1,  0,  0,  0,  0  */
+
+#define O(a) (a*1)
+static const unsigned char eg_rate_shift[16+64+16]={    /* Envelope Generator counter shifts (16 + 64 rates + 16 RKS) */
+/* 16 infinite time rates */
+O(0),O(0),O(0),O(0),O(0),O(0),O(0),O(0),
+O(0),O(0),O(0),O(0),O(0),O(0),O(0),O(0),
+
+/* rates 00-12 */
+O(12),O(12),O(12),O(12),
+O(11),O(11),O(11),O(11),
+O(10),O(10),O(10),O(10),
+O( 9),O( 9),O( 9),O( 9),
+O( 8),O( 8),O( 8),O( 8),
+O( 7),O( 7),O( 7),O( 7),
+O( 6),O( 6),O( 6),O( 6),
+O( 5),O( 5),O( 5),O( 5),
+O( 4),O( 4),O( 4),O( 4),
+O( 3),O( 3),O( 3),O( 3),
+O( 2),O( 2),O( 2),O( 2),
+O( 1),O( 1),O( 1),O( 1),
+O( 0),O( 0),O( 0),O( 0),
+
+/* rate 13 */
+O( 0),O( 0),O( 0),O( 0),
+
+/* rate 14 */
+O( 0),O( 0),O( 0),O( 0),
+
+/* rate 15 */
+O( 0),O( 0),O( 0),O( 0),
+
+/* 16 dummy rates (same as 15 3) */
+O( 0),O( 0),O( 0),O( 0),O( 0),O( 0),O( 0),O( 0),
+O( 0),O( 0),O( 0),O( 0),O( 0),O( 0),O( 0),O( 0),
+
+};
+#undef O
+
+
+/* multiple table */
+#define ML 2
+static const uint8_t mul_tab[16]= {
+/* 1/2, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,10,12,12,15,15 */
+   uint8_t(0.50*ML), uint8_t(1.00*ML), uint8_t(2.00*ML), uint8_t(3.00*ML), uint8_t(4.00*ML), uint8_t(5.00*ML), uint8_t(6.00*ML), uint8_t(7.00*ML),
+   uint8_t(8.00*ML), uint8_t(9.00*ML),uint8_t(10.00*ML),uint8_t(10.00*ML),uint8_t(12.00*ML),uint8_t(12.00*ML),uint8_t(15.00*ML),uint8_t(15.00*ML)
+};
+#undef ML
+
+/*  TL_TAB_LEN is calculated as:
+*   12 - sinus amplitude bits     (Y axis)
+*   2  - sinus sign bit           (Y axis)
+*   TL_RES_LEN - sinus resolution (X axis)
+*/
+#define TL_TAB_LEN (12*2*TL_RES_LEN)
+static signed int tl_tab[TL_TAB_LEN];
+
+#define ENV_QUIET       (TL_TAB_LEN>>4)
+
+/* sin waveform table in 'decibel' scale */
+/* four waveforms on OPL2 type chips */
+static unsigned int sin_tab[SIN_LEN * 4];
+
+
+/* LFO Amplitude Modulation table (verified on real YM3812)
+   27 output levels (triangle waveform); 1 level takes one of: 192, 256 or 448 samples
+
+   Length: 210 elements.
+
+    Each of the elements has to be repeated
+    exactly 64 times (on 64 consecutive samples).
+    The whole table takes: 64 * 210 = 13440 samples.
+
+    When AM = 1 data is used directly
+    When AM = 0 data is divided by 4 before being used (losing precision is important)
+*/
+
+#define LFO_AM_TAB_ELEMENTS 210
+
+static const uint8_t lfo_am_table[LFO_AM_TAB_ELEMENTS] = {
+0,0,0,0,0,0,0,
+1,1,1,1,
+2,2,2,2,
+3,3,3,3,
+4,4,4,4,
+5,5,5,5,
+6,6,6,6,
+7,7,7,7,
+8,8,8,8,
+9,9,9,9,
+10,10,10,10,
+11,11,11,11,
+12,12,12,12,
+13,13,13,13,
+14,14,14,14,
+15,15,15,15,
+16,16,16,16,
+17,17,17,17,
+18,18,18,18,
+19,19,19,19,
+20,20,20,20,
+21,21,21,21,
+22,22,22,22,
+23,23,23,23,
+24,24,24,24,
+25,25,25,25,
+26,26,26,
+25,25,25,25,
+24,24,24,24,
+23,23,23,23,
+22,22,22,22,
+21,21,21,21,
+20,20,20,20,
+19,19,19,19,
+18,18,18,18,
+17,17,17,17,
+16,16,16,16,
+15,15,15,15,
+14,14,14,14,
+13,13,13,13,
+12,12,12,12,
+11,11,11,11,
+10,10,10,10,
+9,9,9,9,
+8,8,8,8,
+7,7,7,7,
+6,6,6,6,
+5,5,5,5,
+4,4,4,4,
+3,3,3,3,
+2,2,2,2,
+1,1,1,1
+};
+
+/* LFO Phase Modulation table (verified on real YM3812) */
+static const int8_t lfo_pm_table[8*8*2] = {
+/* FNUM2/FNUM = 00 0xxxxxxx (0x0000) */
+0, 0, 0, 0, 0, 0, 0, 0, /*LFO PM depth = 0*/
+0, 0, 0, 0, 0, 0, 0, 0, /*LFO PM depth = 1*/
+
+/* FNUM2/FNUM = 00 1xxxxxxx (0x0080) */
+0, 0, 0, 0, 0, 0, 0, 0, /*LFO PM depth = 0*/
+1, 0, 0, 0,-1, 0, 0, 0, /*LFO PM depth = 1*/
+
+/* FNUM2/FNUM = 01 0xxxxxxx (0x0100) */
+1, 0, 0, 0,-1, 0, 0, 0, /*LFO PM depth = 0*/
+2, 1, 0,-1,-2,-1, 0, 1, /*LFO PM depth = 1*/
+
+/* FNUM2/FNUM = 01 1xxxxxxx (0x0180) */
+1, 0, 0, 0,-1, 0, 0, 0, /*LFO PM depth = 0*/
+3, 1, 0,-1,-3,-1, 0, 1, /*LFO PM depth = 1*/
+
+/* FNUM2/FNUM = 10 0xxxxxxx (0x0200) */
+2, 1, 0,-1,-2,-1, 0, 1, /*LFO PM depth = 0*/
+4, 2, 0,-2,-4,-2, 0, 2, /*LFO PM depth = 1*/
+
+/* FNUM2/FNUM = 10 1xxxxxxx (0x0280) */
+2, 1, 0,-1,-2,-1, 0, 1, /*LFO PM depth = 0*/
+5, 2, 0,-2,-5,-2, 0, 2, /*LFO PM depth = 1*/
+
+/* FNUM2/FNUM = 11 0xxxxxxx (0x0300) */
+3, 1, 0,-1,-3,-1, 0, 1, /*LFO PM depth = 0*/
+6, 3, 0,-3,-6,-3, 0, 3, /*LFO PM depth = 1*/
+
+/* FNUM2/FNUM = 11 1xxxxxxx (0x0380) */
+3, 1, 0,-1,-3,-1, 0, 1, /*LFO PM depth = 0*/
+7, 3, 0,-3,-7,-3, 0, 3  /*LFO PM depth = 1*/
+};
+
+
+
+/* work table */
+struct FM_WorkTable
+{
+	signed int phase_modulation;		/* phase modulation input (SLOT 2) */
+	signed int output;
+
+	uint32_t	LFO_AM;
+	int32_t	LFO_PM;
+};
+
+static bool CalcVoice (FM_WorkTable *wt, FM_OPL *OPL, int voice, float *buffer, int length);
+static bool CalcVoice (FM_WorkTable *wt, FM_OPL *OPL, int voice, short *buffer, int length);
+static bool CalcRhythm (FM_WorkTable *wt, FM_OPL *OPL, float *buffer, int length);
+static bool CalcRhythm (FM_WorkTable *wt, FM_OPL *OPL, short *buffer, int length);
+
+
+
+/* status set and IRQ handling */
+static inline void OPL_STATUS_SET(FM_OPL *OPL,int flag)
+{
+	/* set status flag */
+	OPL->status |= flag;
+	if(!(OPL->status & 0x80))
+	{
+		if(OPL->status & OPL->statusmask)
+		{   /* IRQ on */
+			OPL->status |= 0x80;
+		}
+	}
+}
+
+/* status reset and IRQ handling */
+static inline void OPL_STATUS_RESET(FM_OPL *OPL,int flag)
+{
+	/* reset status flag */
+	OPL->status &=~flag;
+	if((OPL->status & 0x80))
+	{
+		if (!(OPL->status & OPL->statusmask) )
+		{
+			OPL->status &= 0x7f;
+		}
+	}
+}
+
+/* IRQ mask set */
+static inline void OPL_STATUSMASK_SET(FM_OPL *OPL,int flag)
+{
+	OPL->statusmask = flag;
+	/* IRQ handling check */
+	OPL_STATUS_SET(OPL,0);
+	OPL_STATUS_RESET(OPL,0);
+}
+
+
+/* advance LFO to next sample */
+static inline void advance_lfo(FM_WorkTable *wt, FM_OPL *OPL)
+{
+	uint8_t tmp;
+
+	/* LFO */
+	OPL->lfo_am_cnt += OPL->lfo_am_inc;
+	if (OPL->lfo_am_cnt >= (uint32_t)(LFO_AM_TAB_ELEMENTS<<LFO_SH) )	/* lfo_am_table is 210 elements long */
+		OPL->lfo_am_cnt -= (LFO_AM_TAB_ELEMENTS<<LFO_SH);
+
+	tmp = lfo_am_table[ OPL->lfo_am_cnt >> LFO_SH ];
+
+	if (OPL->lfo_am_depth)
+		wt->LFO_AM = tmp;
+	else
+		wt->LFO_AM = tmp>>2;
+
+	OPL->lfo_pm_cnt += OPL->lfo_pm_inc;
+	wt->LFO_PM = ((OPL->lfo_pm_cnt>>LFO_SH) & 7) | OPL->lfo_pm_depth_range;
+}
+
+/* advance to next sample */
+static inline void advance(FM_WorkTable *wt, FM_OPL *OPL, int loch, int hich)
+{
+	OPL_CH *CH;
+	OPL_SLOT *op;
+	int i;
+
+	OPL->eg_timer += OPL->eg_timer_add;
+	loch *= 2;
+	hich *= 2;
+
+	while (OPL->eg_timer >= OPL->eg_timer_overflow)
+	{
+		OPL->eg_timer -= OPL->eg_timer_overflow;
+
+		OPL->eg_cnt++;
+
+		for (i = loch; i <= hich + 1; i++)
+		{
+			CH  = &OPL->P_CH[i/2];
+			op  = &CH->SLOT[i&1];
+
+			/* Envelope Generator */
+			switch(op->state)
+			{
+			case EG_ATT:		/* attack phase */
+				if ( !(OPL->eg_cnt & ((1<<op->eg_sh_ar)-1) ) )
+				{
+					op->volume += (~op->volume *
+	                        		           (eg_inc[op->eg_sel_ar + ((OPL->eg_cnt>>op->eg_sh_ar)&7)])
+        			                          ) >>3;
+
+					if (op->volume <= MIN_ATT_INDEX)
+					{
+						op->volume = MIN_ATT_INDEX;
+						op->state = EG_DEC;
+					}
+
+				}
+			break;
+
+			case EG_DEC:    /* decay phase */
+				if ( !(OPL->eg_cnt & ((1<<op->eg_sh_dr)-1) ) )
+				{
+					op->volume += eg_inc[op->eg_sel_dr + ((OPL->eg_cnt>>op->eg_sh_dr)&7)];
+
+					if ( op->volume >= (int32_t)op->sl )
+						op->state = EG_SUS;
+
+				}
+			break;
+
+			case EG_SUS:    /* sustain phase */
+
+				/* this is important behaviour:
+				one can change percusive/non-percussive modes on the fly and
+				the chip will remain in sustain phase - verified on real YM3812 */
+
+				if(op->eg_type)     /* non-percussive mode */
+				{
+									/* do nothing */
+				}
+				else                /* percussive mode */
+				{
+					/* during sustain phase chip adds Release Rate (in percussive mode) */
+					if ( !(OPL->eg_cnt & ((1<<op->eg_sh_rr)-1) ) )
+					{
+						op->volume += eg_inc[op->eg_sel_rr + ((OPL->eg_cnt>>op->eg_sh_rr)&7)];
+
+						if ( op->volume >= MAX_ATT_INDEX )
+							op->volume = MAX_ATT_INDEX;
+					}
+					/* else do nothing in sustain phase */
+				}
+			break;
+
+			case EG_REL:    /* release phase */
+				if ( !(OPL->eg_cnt & ((1<<op->eg_sh_rr)-1) ) )
+				{
+					op->volume += eg_inc[op->eg_sel_rr + ((OPL->eg_cnt>>op->eg_sh_rr)&7)];
+
+					if ( op->volume >= MAX_ATT_INDEX )
+					{
+						op->volume = MAX_ATT_INDEX;
+						op->state = EG_OFF;
+					}
+
+				}
+			break;
+
+			default:
+			break;
+			}
+
+			/* Phase Generator */
+			if(op->vib)
+			{
+				uint8_t block;
+				unsigned int block_fnum = CH->block_fnum;
+
+				unsigned int fnum_lfo   = (block_fnum&0x0380) >> 7;
+
+	signed int lfo_fn_table_index_offset = lfo_pm_table[wt->LFO_PM + 16*fnum_lfo ];
+
+				if (lfo_fn_table_index_offset)	/* LFO phase modulation active */
+				{
+					block_fnum += lfo_fn_table_index_offset;
+					block = (block_fnum&0x1c00) >> 10;
+					op->Cnt += (OPL->fn_tab[block_fnum&0x03ff] >> (7-block)) * op->mul;
+				}
+				else	/* LFO phase modulation  = zero */
+				{
+					op->Cnt += op->Incr;
+				}
+			}
+			else	/* LFO phase modulation disabled for this operator */
+			{
+				op->Cnt += op->Incr;
+			}
+		}
+	}
+}
+
+static inline void advance_noise(FM_OPL *OPL)
+{
+	int i;
+
+	/*  The Noise Generator of the YM3812 is 23-bit shift register.
+	*   Period is equal to 2^23-2 samples.
+	*   Register works at sampling frequency of the chip, so output
+	*   can change on every sample.
+	*
+	*   Output of the register and input to the bit 22 is:
+	*   bit0 XOR bit14 XOR bit15 XOR bit22
+	*
+	*   Simply use bit 22 as the noise output.
+	*/
+
+	OPL->noise_p += OPL->noise_f;
+	i = OPL->noise_p >> FREQ_SH;        /* number of events (shifts of the shift register) */
+	OPL->noise_p &= FREQ_MASK;
+	while (i)
+	{
+		/*
+		uint32_t j;
+		j = ( (OPL->noise_rng) ^ (OPL->noise_rng>>14) ^ (OPL->noise_rng>>15) ^ (OPL->noise_rng>>22) ) & 1;
+		OPL->noise_rng = (j<<22) | (OPL->noise_rng>>1);
+		*/
+
+		/*
+		    Instead of doing all the logic operations above, we
+		    use a trick here (and use bit 0 as the noise output).
+		    The difference is only that the noise bit changes one
+		    step ahead. This doesn't matter since we don't know
+			what is real state of the noise_rng after the reset.
+		*/
+
+		if (OPL->noise_rng & 1) OPL->noise_rng ^= 0x800302;
+		OPL->noise_rng >>= 1;
+
+		i--;
+	}
+}
+
+
+static inline signed int op_calc(uint32_t phase, unsigned int env, signed int pm, unsigned int wave_tab)
+{
+	uint32_t p;
+
+	p = (env<<4) + sin_tab[wave_tab + ((((signed int)((phase & ~FREQ_MASK) + (pm<<16))) >> FREQ_SH ) & SIN_MASK) ];
+
+	if (p >= TL_TAB_LEN)
+		return 0;
+	return tl_tab[p];
+}
+
+static inline signed int op_calc1(uint32_t phase, unsigned int env, signed int pm, unsigned int wave_tab)
+{
+	uint32_t p;
+
+	p = (env<<4) + sin_tab[wave_tab + ((((signed int)((phase & ~FREQ_MASK) + pm      )) >> FREQ_SH ) & SIN_MASK) ];
+
+	if (p >= TL_TAB_LEN)
+		return 0;
+	return tl_tab[p];
+}
+
+
+#define volume_calc(OP) ((OP)->TLL + ((uint32_t)(OP)->volume) + (wt->LFO_AM & (OP)->AMmask))
+
+/* calculate output */
+static inline float OPL_CALC_CH( FM_WorkTable *wt, OPL_CH *CH )
+{
+	OPL_SLOT *SLOT;
+	unsigned int env;
+	signed int out;
+
+	wt->phase_modulation = 0;
+
+	/* SLOT 1 */
+	SLOT = &CH->SLOT[SLOT1];
+	env  = volume_calc(SLOT);
+	out  = SLOT->op1_out[0] + SLOT->op1_out[1];
+	SLOT->op1_out[0] = SLOT->op1_out[1];
+	*SLOT->connect1 += SLOT->op1_out[0];
+	SLOT->op1_out[1] = 0;
+	if( env < ENV_QUIET )
+	{
+		if (!SLOT->FB)
+			out = 0;
+		SLOT->op1_out[1] = op_calc1(SLOT->Cnt, env, (out<<SLOT->FB), SLOT->wavetable );
+	}
+
+	/* SLOT 2 */
+	SLOT++;
+	env = volume_calc(SLOT);
+	if( env < ENV_QUIET )
+	{
+		wt->output += op_calc(SLOT->Cnt, env, wt->phase_modulation, SLOT->wavetable);
+		/* [RH] Convert to floating point. */
+		return float(wt->output) / 10240;
+	}
+	return 0;
+}
+
+static inline short OPL_CALC_CH_S( FM_WorkTable *wt, OPL_CH *CH )
+{
+	OPL_SLOT *SLOT;
+	unsigned int env;
+	signed int out;
+
+	wt->phase_modulation = 0;
+
+	/* SLOT 1 */
+	SLOT = &CH->SLOT[SLOT1];
+	env  = volume_calc(SLOT);
+	out  = SLOT->op1_out[0] + SLOT->op1_out[1];
+	SLOT->op1_out[0] = SLOT->op1_out[1];
+	*SLOT->connect1 += SLOT->op1_out[0];
+	SLOT->op1_out[1] = 0;
+	if( env < ENV_QUIET )
+	{
+		if (!SLOT->FB)
+			out = 0;
+		SLOT->op1_out[1] = op_calc1(SLOT->Cnt, env, (out<<SLOT->FB), SLOT->wavetable );
+	}
+
+	/* SLOT 2 */
+	SLOT++;
+	env = volume_calc(SLOT);
+	if( env < ENV_QUIET )
+	{
+		wt->output += op_calc(SLOT->Cnt, env, wt->phase_modulation, SLOT->wavetable);
+		return wt->output;
+	}
+	return 0;
+}
+
+/*
+    operators used in the rhythm sounds generation process:
+
+    Envelope Generator:
+
+channel  operator  register number   Bass  High  Snare Tom  Top
+/ slot   number    TL ARDR SLRR Wave Drum  Hat   Drum  Tom  Cymbal
+ 6 / 0   12        50  70   90   f0  +
+ 6 / 1   15        53  73   93   f3  +
+ 7 / 0   13        51  71   91   f1        +
+ 7 / 1   16        54  74   94   f4              +
+ 8 / 0   14        52  72   92   f2                    +
+ 8 / 1   17        55  75   95   f5                          +
+
+	Phase Generator:
+
+channel  operator  register number   Bass  High  Snare Tom  Top
+/ slot   number    MULTIPLE          Drum  Hat   Drum  Tom  Cymbal
+ 6 / 0   12        30                +
+ 6 / 1   15        33                +
+ 7 / 0   13        31                      +     +           +
+ 7 / 1   16        34                -----  n o t  u s e d -----
+ 8 / 0   14        32                                  +
+ 8 / 1   17        35                      +                 +
+
+channel  operator  register number   Bass  High  Snare Tom  Top
+number   number    BLK/FNUM2 FNUM    Drum  Hat   Drum  Tom  Cymbal
+   6     12,15     B6        A6      +
+
+   7     13,16     B7        A7            +     +           +
+
+   8     14,17     B8        A8            +           +     +
+
+*/
+
+/* calculate rhythm */
+
+static inline void OPL_CALC_RH( FM_WorkTable *wt, OPL_CH *CH, unsigned int noise )
+{
+	OPL_SLOT *SLOT;
+	signed int out;
+	unsigned int env;
+
+
+	/* Bass Drum (verified on real YM3812):
+	  - depends on the channel 6 'connect' register:
+	      when connect = 0 it works the same as in normal (non-rhythm) mode (op1->op2->out)
+	      when connect = 1 _only_ operator 2 is present on output (op2->out), operator 1 is ignored
+	  - output sample always is multiplied by 2
+	*/
+
+	wt->phase_modulation = 0;
+	/* SLOT 1 */
+	SLOT = &CH[6].SLOT[SLOT1];
+	env = volume_calc(SLOT);
+
+	out = SLOT->op1_out[0] + SLOT->op1_out[1];
+	SLOT->op1_out[0] = SLOT->op1_out[1];
+
+	if (!SLOT->CON)
+		wt->phase_modulation = SLOT->op1_out[0];
+	/* else ignore output of operator 1 */
+
+	SLOT->op1_out[1] = 0;
+	if( env < ENV_QUIET )
+	{
+		if (!SLOT->FB)
+			out = 0;
+		SLOT->op1_out[1] = op_calc1(SLOT->Cnt, env, (out<<SLOT->FB), SLOT->wavetable );
+	}
+
+	/* SLOT 2 */
+	SLOT++;
+	env = volume_calc(SLOT);
+	if( env < ENV_QUIET )
+		wt->output += op_calc(SLOT->Cnt, env, wt->phase_modulation, SLOT->wavetable) * 2;
+
+
+	/* Phase generation is based on: */
+	/* HH  (13) channel 7->slot 1 combined with channel 8->slot 2 (same combination as TOP CYMBAL but different output phases) */
+	/* SD  (16) channel 7->slot 1 */
+	/* TOM (14) channel 8->slot 1 */
+	/* TOP (17) channel 7->slot 1 combined with channel 8->slot 2 (same combination as HIGH HAT but different output phases) */
+
+	/* Envelope generation based on: */
+	/* HH  channel 7->slot1 */
+	/* SD  channel 7->slot2 */
+	/* TOM channel 8->slot1 */
+	/* TOP channel 8->slot2 */
+
+
+	/* The following formulas can be well optimized.
+	   I leave them in direct form for now (in case I've missed something).
+	*/
+
+	/* High Hat (verified on real YM3812) */
+	env = volume_calc(&CH[7].SLOT[SLOT1]);
+	if( env < ENV_QUIET )
+	{
+
+		/* high hat phase generation:
+			phase = d0 or 234 (based on frequency only)
+			phase = 34 or 2d0 (based on noise)
+		*/
+
+		/* base frequency derived from operator 1 in channel 7 */
+		unsigned char bit7 = ((CH[7].SLOT[SLOT1].Cnt>>FREQ_SH)>>7)&1;
+		unsigned char bit3 = ((CH[7].SLOT[SLOT1].Cnt>>FREQ_SH)>>3)&1;
+		unsigned char bit2 = ((CH[7].SLOT[SLOT1].Cnt>>FREQ_SH)>>2)&1;
+
+		unsigned char res1 = (bit2 ^ bit7) | bit3;
+
+		/* when res1 = 0 phase = 0x000 | 0xd0; */
+		/* when res1 = 1 phase = 0x200 | (0xd0>>2); */
+		uint32_t phase = res1 ? (0x200|(0xd0>>2)) : 0xd0;
+
+		/* enable gate based on frequency of operator 2 in channel 8 */
+		unsigned char bit5e= ((CH[8].SLOT[SLOT2].Cnt>>FREQ_SH)>>5)&1;
+		unsigned char bit3e= ((CH[8].SLOT[SLOT2].Cnt>>FREQ_SH)>>3)&1;
+
+		unsigned char res2 = (bit3e ^ bit5e);
+
+		/* when res2 = 0 pass the phase from calculation above (res1); */
+		/* when res2 = 1 phase = 0x200 | (0xd0>>2); */
+		if (res2)
+			phase = (0x200|(0xd0>>2));
+
+
+		/* when phase & 0x200 is set and noise=1 then phase = 0x200|0xd0 */
+		/* when phase & 0x200 is set and noise=0 then phase = 0x200|(0xd0>>2), ie no change */
+		if (phase&0x200)
+		{
+			if (noise)
+				phase = 0x200|0xd0;
+		}
+		else
+		/* when phase & 0x200 is clear and noise=1 then phase = 0xd0>>2 */
+		/* when phase & 0x200 is clear and noise=0 then phase = 0xd0, ie no change */
+		{
+			if (noise)
+				phase = 0xd0>>2;
+		}
+
+		wt->output += op_calc(phase<<FREQ_SH, env, 0, CH[7].SLOT[SLOT1].wavetable) * 2;
+	}
+
+	/* Snare Drum (verified on real YM3812) */
+	env = volume_calc(&CH[7].SLOT[SLOT2]);
+	if( env < ENV_QUIET )
+	{
+		/* base frequency derived from operator 1 in channel 7 */
+		unsigned char bit8 = ((CH[7].SLOT[SLOT1].Cnt>>FREQ_SH)>>8)&1;
+
+		/* when bit8 = 0 phase = 0x100; */
+		/* when bit8 = 1 phase = 0x200; */
+		uint32_t phase = bit8 ? 0x200 : 0x100;
+
+		/* Noise bit XOR'es phase by 0x100 */
+		/* when noisebit = 0 pass the phase from calculation above */
+		/* when noisebit = 1 phase ^= 0x100; */
+		/* in other words: phase ^= (noisebit<<8); */
+		if (noise)
+			phase ^= 0x100;
+
+		wt->output += op_calc(phase<<FREQ_SH, env, 0, CH[7].SLOT[SLOT2].wavetable) * 2;
+	}
+
+	/* Tom Tom (verified on real YM3812) */
+	env = volume_calc(&CH[8].SLOT[SLOT1]);
+	if( env < ENV_QUIET )
+		wt->output += op_calc(CH[8].SLOT[SLOT1].Cnt, env, 0, CH[8].SLOT[SLOT2].wavetable) * 2;
+
+	/* Top Cymbal (verified on real YM3812) */
+	env = volume_calc(&CH[8].SLOT[SLOT2]);
+	if( env < ENV_QUIET )
+	{
+		/* base frequency derived from operator 1 in channel 7 */
+		unsigned char bit7 = ((CH[7].SLOT[SLOT1].Cnt>>FREQ_SH)>>7)&1;
+		unsigned char bit3 = ((CH[7].SLOT[SLOT1].Cnt>>FREQ_SH)>>3)&1;
+		unsigned char bit2 = ((CH[7].SLOT[SLOT1].Cnt>>FREQ_SH)>>2)&1;
+
+		unsigned char res1 = (bit2 ^ bit7) | bit3;
+
+		/* when res1 = 0 phase = 0x000 | 0x100; */
+		/* when res1 = 1 phase = 0x200 | 0x100; */
+		uint32_t phase = res1 ? 0x300 : 0x100;
+
+		/* enable gate based on frequency of operator 2 in channel 8 */
+		unsigned char bit5e= ((CH[8].SLOT[SLOT2].Cnt>>FREQ_SH)>>5)&1;
+		unsigned char bit3e= ((CH[8].SLOT[SLOT2].Cnt>>FREQ_SH)>>3)&1;
+
+		unsigned char res2 = (bit3e ^ bit5e);
+		/* when res2 = 0 pass the phase from calculation above (res1); */
+		/* when res2 = 1 phase = 0x200 | 0x100; */
+		if (res2)
+			phase = 0x300;
+
+		wt->output += op_calc(phase<<FREQ_SH, env, 0, CH[8].SLOT[SLOT2].wavetable) * 2;
+	}
+}
+
+
+/* generic table initialize */
+static void init_tables(void)
+{
+	signed int i,x;
+	signed int n;
+	double o,m;
+
+	/* We only need to do this once. */
+	static bool did_init = false;
+
+	if (did_init)
+	{
+		return;
+	}
+
+	for (x=0; x<TL_RES_LEN; x++)
+	{
+		m = (1<<16) / pow(2.0, (x+1) * (ENV_STEP/4.0) / 8.0);
+		m = floor(m);
+
+		/* we never reach (1<<16) here due to the (x+1) */
+		/* result fits within 16 bits at maximum */
+
+		n = (int)m;     /* 16 bits here */
+		n >>= 4;        /* 12 bits here */
+		n = (n+1)>>1;	/* round to nearest */
+						/* 11 bits here (rounded) */
+		n <<= 1;        /* 12 bits here (as in real chip) */
+		tl_tab[ x*2 + 0 ] = n;
+		tl_tab[ x*2 + 1 ] = -tl_tab[ x*2 + 0 ];
+
+		for (i=1; i<12; i++)
+		{
+			tl_tab[ x*2+0 + i*2*TL_RES_LEN ] =  tl_tab[ x*2+0 ]>>i;
+			tl_tab[ x*2+1 + i*2*TL_RES_LEN ] = -tl_tab[ x*2+0 ]>>i;
+		}
+	}
+
+	for (i=0; i<SIN_LEN; i++)
+	{
+		/* non-standard sinus */
+		m = sin( ((i*2)+1) * PI / SIN_LEN ); /* checked against the real chip */
+
+		/* we never reach zero here due to ((i*2)+1) */
+
+		if (m>0.0)
+			o = 8*log(1.0/m)/log(2.0);  /* convert to 'decibels' */
+		else
+			o = 8*log(-1.0/m)/log(2.0); /* convert to 'decibels' */
+
+		o = o / (ENV_STEP/4);
+
+		n = (int)(2.0*o);
+		if (n&1)                        /* round to nearest */
+			n = (n>>1)+1;
+		else
+			n = n>>1;
+
+		sin_tab[ i ] = n*2 + (m>=0.0? 0: 1 );
+	}
+
+	for (i=0; i<SIN_LEN; i++)
+	{
+		/* waveform 1:  __      __     */
+		/*             /  \____/  \____*/
+		/* output only first half of the sinus waveform (positive one) */
+
+		if (i & (1<<(SIN_BITS-1)) )
+			sin_tab[1*SIN_LEN+i] = TL_TAB_LEN;
+		else
+			sin_tab[1*SIN_LEN+i] = sin_tab[i];
+
+		/* waveform 2:  __  __  __  __ */
+		/*             /  \/  \/  \/  \*/
+		/* abs(sin) */
+
+		sin_tab[2*SIN_LEN+i] = sin_tab[i & (SIN_MASK>>1) ];
+
+		/* waveform 3:  _   _   _   _  */
+		/*             / |_/ |_/ |_/ |_*/
+		/* abs(output only first quarter of the sinus waveform) */
+
+		if (i & (1<<(SIN_BITS-2)) )
+			sin_tab[3*SIN_LEN+i] = TL_TAB_LEN;
+		else
+			sin_tab[3*SIN_LEN+i] = sin_tab[i & (SIN_MASK>>2)];
+	}
+
+	did_init = true;
+}
+
+static void OPL_initalize(FM_OPL *OPL)
+{
+	int i;
+
+	/* make fnumber -> increment counter table */
+	for( i=0 ; i < 1024 ; i++ )
+	{
+		/* opn phase increment counter = 20bit */
+		OPL->fn_tab[i] = (uint32_t)( (double)i * 64 * OPL_FREQBASE * (1<<(FREQ_SH-10)) ); /* -10 because chip works with 10.10 fixed point, while we use 16.16 */
+	}
+
+	/* Amplitude modulation: 27 output levels (triangle waveform); 1 level takes one of: 192, 256 or 448 samples */
+	/* One entry from LFO_AM_TABLE lasts for 64 samples */
+	OPL->lfo_am_inc = uint32_t((1.0 / 64.0 ) * (1<<LFO_SH) * OPL_FREQBASE);
+
+	/* Vibrato: 8 output levels (triangle waveform); 1 level takes 1024 samples */
+	OPL->lfo_pm_inc = uint32_t((1.0 / 1024.0) * (1<<LFO_SH) * OPL_FREQBASE);
+
+	OPL->eg_timer_add  = uint32_t((1<<EG_SH)  * OPL_FREQBASE);
+	OPL->eg_timer_overflow = uint32_t(( 1 ) * (1<<EG_SH));
+
+	// [RH] Support full MIDI panning. (But default to mono and center panning.)
+	OPL->IsStereo = false;
+	for (int i = 0; i < 9; ++i)
+	{
+		OPL->P_CH[i].LeftVol = (float)CENTER_PANNING_POWER;
+		OPL->P_CH[i].RightVol = (float)CENTER_PANNING_POWER;
+	}
+}
+
+static inline void FM_KEYON(OPL_SLOT *SLOT, uint32_t key_set)
+{
+	if( !SLOT->key )
+	{
+		/* restart Phase Generator */
+		SLOT->Cnt = 0;
+		/* phase -> Attack */
+		SLOT->state = EG_ATT;
+	}
+	SLOT->key |= key_set;
+}
+
+static inline void FM_KEYOFF(OPL_SLOT *SLOT, uint32_t key_clr)
+{
+	if( SLOT->key )
+	{
+		SLOT->key &= key_clr;
+
+		if( !SLOT->key )
+		{
+			/* phase -> Release */
+			if (SLOT->state>EG_REL)
+				SLOT->state = EG_REL;
+		}
+	}
+}
+
+/* update phase increment counter of operator (also update the EG rates if necessary) */
+static inline void CALC_FCSLOT(OPL_CH *CH,OPL_SLOT *SLOT)
+{
+	int ksr;
+
+	/* (frequency) phase increment counter */
+	SLOT->Incr = CH->fc * SLOT->mul;
+	ksr = CH->kcode >> SLOT->KSR;
+
+	if( SLOT->ksr != ksr )
+	{
+		SLOT->ksr = ksr;
+
+		/* calculate envelope generator rates */
+		if ((SLOT->ar + SLOT->ksr) < 16+62)
+		{
+			SLOT->eg_sh_ar  = eg_rate_shift [SLOT->ar + SLOT->ksr ];
+			SLOT->eg_sel_ar = eg_rate_select[SLOT->ar + SLOT->ksr ];
+		}
+		else
+		{
+			SLOT->eg_sh_ar  = 0;
+			SLOT->eg_sel_ar = 13*RATE_STEPS;
+		}
+		SLOT->eg_sh_dr  = eg_rate_shift [SLOT->dr + SLOT->ksr ];
+		SLOT->eg_sel_dr = eg_rate_select[SLOT->dr + SLOT->ksr ];
+		SLOT->eg_sh_rr  = eg_rate_shift [SLOT->rr + SLOT->ksr ];
+		SLOT->eg_sel_rr = eg_rate_select[SLOT->rr + SLOT->ksr ];
+	}
+}
+
+/* set multi,am,vib,EG-TYP,KSR,mul */
+static inline void set_mul(FM_OPL *OPL,int slot,int v)
+{
+	OPL_CH   *CH   = &OPL->P_CH[slot/2];
+	OPL_SLOT *SLOT = &CH->SLOT[slot&1];
+
+	SLOT->mul     = mul_tab[v&0x0f];
+	SLOT->KSR     = (v&0x10) ? 0 : 2;
+	SLOT->eg_type = (v&0x20);
+	SLOT->vib     = (v&0x40);
+	SLOT->AMmask  = (v&0x80) ? ~0 : 0;
+	CALC_FCSLOT(CH,SLOT);
+}
+
+/* set ksl & tl */
+static inline void set_ksl_tl(FM_OPL *OPL,int slot,int v)
+{
+	OPL_CH   *CH   = &OPL->P_CH[slot/2];
+	OPL_SLOT *SLOT = &CH->SLOT[slot&1];
+
+	SLOT->ksl = ksl_shift[v >> 6];
+	SLOT->TL  = (v&0x3f)<<(ENV_BITS-1-7); /* 7 bits TL (bit 6 = always 0) */
+
+	SLOT->TLL = SLOT->TL + (CH->ksl_base>>SLOT->ksl);
+}
+
+/* set attack rate & decay rate  */
+static inline void set_ar_dr(FM_OPL *OPL,int slot,int v)
+{
+	OPL_CH   *CH   = &OPL->P_CH[slot/2];
+	OPL_SLOT *SLOT = &CH->SLOT[slot&1];
+
+	SLOT->ar = (v>>4)  ? 16 + ((v>>4)  <<2) : 0;
+
+	if ((SLOT->ar + SLOT->ksr) < 16+62)
+	{
+		SLOT->eg_sh_ar  = eg_rate_shift [SLOT->ar + SLOT->ksr ];
+		SLOT->eg_sel_ar = eg_rate_select[SLOT->ar + SLOT->ksr ];
+	}
+	else
+	{
+		SLOT->eg_sh_ar  = 0;
+		SLOT->eg_sel_ar = 13*RATE_STEPS;
+	}
+
+	SLOT->dr    = (v&0x0f)? 16 + ((v&0x0f)<<2) : 0;
+	SLOT->eg_sh_dr  = eg_rate_shift [SLOT->dr + SLOT->ksr ];
+	SLOT->eg_sel_dr = eg_rate_select[SLOT->dr + SLOT->ksr ];
+}
+
+/* set sustain level & release rate */
+static inline void set_sl_rr(FM_OPL *OPL,int slot,int v)
+{
+	OPL_CH   *CH   = &OPL->P_CH[slot/2];
+	OPL_SLOT *SLOT = &CH->SLOT[slot&1];
+
+	SLOT->sl  = sl_tab[ v>>4 ];
+
+	SLOT->rr  = (v&0x0f)? 16 + ((v&0x0f)<<2) : 0;
+	SLOT->eg_sh_rr  = eg_rate_shift [SLOT->rr + SLOT->ksr ];
+	SLOT->eg_sel_rr = eg_rate_select[SLOT->rr + SLOT->ksr ];
+}
+
+
+/* write a value v to register r on OPL chip */
+static void WriteRegister(FM_WorkTable *wt, FM_OPL *OPL, int r, int v)
+{
+	OPL_CH *CH;
+	int slot;
+	int block_fnum;
+
+	/* adjust bus to 8 bits */
+	r &= 0xff;
+	v &= 0xff;
+
+	switch(r&0xe0)
+	{
+	case 0x00:  /* 00-1f:control */
+		switch(r&0x1f)
+		{
+		case 0x01:	/* waveform select enable */
+			OPL->wavesel = v&0x20;
+			break;
+		case 0x02:  /* Timer 1 */
+			OPL->T[0] = (256-v)*4;
+			break;
+		case 0x03:  /* Timer 2 */
+			OPL->T[1] = (256-v)*16;
+			break;
+		case 0x04:  /* IRQ clear / mask and Timer enable */
+			if(v&0x80)
+			{   /* IRQ flag clear */
+				OPL_STATUS_RESET(OPL,0x7f-0x08); /* don't reset BFRDY flag or we will have to call deltat module to set the flag */
+			}
+			else
+			{   /* set IRQ mask ,timer enable*/
+				uint8_t st1 = v&1;
+				uint8_t st2 = (v>>1)&1;
+
+				/* IRQRST,T1MSK,t2MSK,EOSMSK,BRMSK,x,ST2,ST1 */
+				OPL_STATUS_RESET(OPL, v & (0x78-0x08) );
+				OPL_STATUSMASK_SET(OPL, (~v) & 0x78 );
+
+				/* timer 2 */
+				if(OPL->st[1] != st2)
+				{
+					OPL->st[1] = st2;
+				}
+				/* timer 1 */
+				if(OPL->st[0] != st1)
+				{
+					OPL->st[0] = st1;
+				}
+			}
+			break;
+		case 0x08:	/* MODE,DELTA-T control 2 : CSM,NOTESEL,x,x,smpl,da/ad,64k,rom */
+			OPL->mode = v;
+			break;
+		}
+		break;
+	case 0x20:  /* am ON, vib ON, ksr, eg_type, mul */
+		slot = slot_array[r&0x1f];
+		if(slot < 0) return;
+		set_mul(OPL,slot,v);
+		break;
+	case 0x40:
+		slot = slot_array[r&0x1f];
+		if(slot < 0) return;
+		set_ksl_tl(OPL,slot,v);
+		break;
+	case 0x60:
+		slot = slot_array[r&0x1f];
+		if(slot < 0) return;
+		set_ar_dr(OPL,slot,v);
+		break;
+	case 0x80:
+		slot = slot_array[r&0x1f];
+		if(slot < 0) return;
+		set_sl_rr(OPL,slot,v);
+		break;
+	case 0xa0:
+		if (r == 0xbd)          /* am depth, vibrato depth, r,bd,sd,tom,tc,hh */
+		{
+			OPL->lfo_am_depth = v & 0x80;
+			OPL->lfo_pm_depth_range = (v&0x40) ? 8 : 0;
+
+			OPL->rhythm  = v&0x3f;
+
+			if(OPL->rhythm&0x20)
+			{
+				/* BD key on/off */
+				if(v&0x10)
+				{
+					FM_KEYON (&OPL->P_CH[6].SLOT[SLOT1], 2);
+					FM_KEYON (&OPL->P_CH[6].SLOT[SLOT2], 2);
+				}
+				else
+				{
+					FM_KEYOFF(&OPL->P_CH[6].SLOT[SLOT1],~2);
+					FM_KEYOFF(&OPL->P_CH[6].SLOT[SLOT2],~2);
+				}
+				/* HH key on/off */
+				if(v&0x01) FM_KEYON (&OPL->P_CH[7].SLOT[SLOT1], 2);
+				else       FM_KEYOFF(&OPL->P_CH[7].SLOT[SLOT1],~2);
+				/* SD key on/off */
+				if(v&0x08) FM_KEYON (&OPL->P_CH[7].SLOT[SLOT2], 2);
+				else       FM_KEYOFF(&OPL->P_CH[7].SLOT[SLOT2],~2);
+				/* TOM key on/off */
+				if(v&0x04) FM_KEYON (&OPL->P_CH[8].SLOT[SLOT1], 2);
+				else       FM_KEYOFF(&OPL->P_CH[8].SLOT[SLOT1],~2);
+				/* TOP-CY key on/off */
+				if(v&0x02) FM_KEYON (&OPL->P_CH[8].SLOT[SLOT2], 2);
+				else       FM_KEYOFF(&OPL->P_CH[8].SLOT[SLOT2],~2);
+			}
+			else
+			{
+				/* BD key off */
+				FM_KEYOFF(&OPL->P_CH[6].SLOT[SLOT1],~2);
+				FM_KEYOFF(&OPL->P_CH[6].SLOT[SLOT2],~2);
+				/* HH key off */
+				FM_KEYOFF(&OPL->P_CH[7].SLOT[SLOT1],~2);
+				/* SD key off */
+				FM_KEYOFF(&OPL->P_CH[7].SLOT[SLOT2],~2);
+				/* TOM key off */
+				FM_KEYOFF(&OPL->P_CH[8].SLOT[SLOT1],~2);
+				/* TOP-CY off */
+				FM_KEYOFF(&OPL->P_CH[8].SLOT[SLOT2],~2);
+			}
+			return;
+		}
+		/* keyon,block,fnum */
+		if( (r&0x0f) > 8) return;
+		CH = &OPL->P_CH[r&0x0f];
+		if(!(r&0x10))
+		{   /* a0-a8 */
+			block_fnum  = (CH->block_fnum&0x1f00) | v;
+		}
+		else
+		{   /* b0-b8 */
+			block_fnum = ((v&0x1f)<<8) | (CH->block_fnum&0xff);
+
+			if(v&0x20)
+			{
+				FM_KEYON (&CH->SLOT[SLOT1], 1);
+				FM_KEYON (&CH->SLOT[SLOT2], 1);
+			}
+			else
+			{
+				FM_KEYOFF(&CH->SLOT[SLOT1],~1);
+				FM_KEYOFF(&CH->SLOT[SLOT2],~1);
+			}
+		}
+		/* update */
+		if(CH->block_fnum != (uint32_t)block_fnum)
+		{
+			uint8_t block  = block_fnum >> 10;
+
+			CH->block_fnum = block_fnum;
+
+			CH->ksl_base = ksl_tab[block_fnum>>6];
+			CH->fc       = OPL->fn_tab[block_fnum&0x03ff] >> (7-block);
+
+			/* BLK 2,1,0 bits -> bits 3,2,1 of kcode */
+			CH->kcode    = (CH->block_fnum&0x1c00)>>9;
+
+				/* the info below is actually opposite to what is stated in the Manuals (verifed on real YM3812) */
+			/* if notesel == 0 -> lsb of kcode is bit 10 (MSB) of fnum  */
+			/* if notesel == 1 -> lsb of kcode is bit 9 (MSB-1) of fnum */
+			if (OPL->mode&0x40)
+				CH->kcode |= (CH->block_fnum&0x100)>>8; /* notesel == 1 */
+			else
+				CH->kcode |= (CH->block_fnum&0x200)>>9; /* notesel == 0 */
+
+			/* refresh Total Level in both SLOTs of this channel */
+			CH->SLOT[SLOT1].TLL = CH->SLOT[SLOT1].TL + (CH->ksl_base>>CH->SLOT[SLOT1].ksl);
+			CH->SLOT[SLOT2].TLL = CH->SLOT[SLOT2].TL + (CH->ksl_base>>CH->SLOT[SLOT2].ksl);
+
+			/* refresh frequency counter in both SLOTs of this channel */
+			CALC_FCSLOT(CH,&CH->SLOT[SLOT1]);
+			CALC_FCSLOT(CH,&CH->SLOT[SLOT2]);
+		}
+		break;
+	case 0xc0:
+		/* FB,C */
+		if( (r&0x0f) > 8) return;
+		CH = &OPL->P_CH[r&0x0f];
+		CH->SLOT[SLOT1].FB  = (v>>1)&7 ? ((v>>1)&7) + 7 : 0;
+		CH->SLOT[SLOT1].CON = v&1;
+		CH->SLOT[SLOT1].connect1 = CH->SLOT[SLOT1].CON ? &wt->output : &wt->phase_modulation;
+		break;
+	case 0xe0: /* waveform select */
+		/* simply ignore write to the waveform select register if selecting not enabled in test register */
+		if(OPL->wavesel)
+		{
+			slot = slot_array[r&0x1f];
+			if(slot < 0) return;
+			CH = &OPL->P_CH[slot/2];
+
+			CH->SLOT[slot&1].wavetable = (v&0x03)*SIN_LEN;
+		}
+		break;
+	}
+}
+
+static void OPLResetChip(FM_WorkTable *wt, FM_OPL *OPL)
+{
+	int c,s;
+	int i;
+
+	OPL->eg_timer = 0;
+	OPL->eg_cnt   = 0;
+
+	OPL->noise_rng = 1; /* noise shift register */
+	OPL->mode   = 0;    /* normal mode */
+	OPL_STATUS_RESET(OPL,0x7f);
+
+	/* reset with register write */
+	WriteRegister(wt,OPL,0x01,0); /* wavesel disable */
+	WriteRegister(wt,OPL,0x02,0); /* Timer1 */
+	WriteRegister(wt,OPL,0x03,0); /* Timer2 */
+	WriteRegister(wt,OPL,0x04,0); /* IRQ mask clear */
+	for(i = 0xff ; i >= 0x20 ; i-- ) WriteRegister(wt,OPL,i,0);
+
+	/* reset operator parameters */
+	for( c = 0 ; c < 9 ; c++ )
+	{
+		OPL_CH *CH = &OPL->P_CH[c];
+		for(s = 0 ; s < 2 ; s++ )
+		{
+			/* wave table */
+			CH->SLOT[s].wavetable = 0;
+			CH->SLOT[s].state     = EG_OFF;
+			CH->SLOT[s].volume    = MAX_ATT_INDEX;
+		}
+	}
+}
+
+
+class YM3812 : public OPLEmul
+{
+private:
+	FM_OPL Chip;
+	FM_WorkTable WorkTable;
+
+public:
+	/* Create one of virtual YM3812 */
+	YM3812(bool stereo)
+	{
+		memset(&WorkTable, 0, sizeof(WorkTable));
+		init_tables();
+
+		/* clear */
+		memset(&Chip, 0, sizeof(Chip));
+
+		/* init global tables */
+		OPL_initalize(&Chip);
+
+		Chip.IsStereo = stereo;
+
+		Reset();
+	}
+
+	/* YM3812 I/O interface */
+	void WriteReg(int reg, int v)
+	{
+		WriteRegister(&WorkTable, &Chip, reg & 0xff, v);
+	}
+
+	void Reset()
+	{
+		OPLResetChip(&WorkTable, &Chip);
+	}
+
+	/* [RH] Full support for MIDI panning */
+	void SetPanning(int c, float left, float right)
+	{
+		Chip.P_CH[c].LeftVol = left;
+		Chip.P_CH[c].RightVol = right;
+	}
+
+
+	/*
+	** Generate samples for one of the YM3812's
+	**
+	** '*buffer' is the output buffer pointer
+	** 'length' is the number of samples that should be generated
+	*/
+	void Update(float *buffer, int length)
+	{
+		int i;
+
+		uint8_t		rhythm = Chip.rhythm&0x20;
+
+		uint32_t lfo_am_cnt_bak = Chip.lfo_am_cnt;
+		uint32_t eg_timer_bak = Chip.eg_timer;
+		uint32_t eg_cnt_bak = Chip.eg_cnt;
+
+		uint32_t lfo_am_cnt_out = lfo_am_cnt_bak;
+		uint32_t eg_timer_out = eg_timer_bak;
+		uint32_t eg_cnt_out = eg_cnt_bak;
+
+		for (i = 0; i <= (rhythm ? 5 : 8); ++i)
+		{
+			Chip.lfo_am_cnt = lfo_am_cnt_bak;
+			Chip.eg_timer = eg_timer_bak;
+			Chip.eg_cnt = eg_cnt_bak;
+			if (CalcVoice (&WorkTable, &Chip, i, buffer, length))
+			{
+				lfo_am_cnt_out = Chip.lfo_am_cnt;
+				eg_timer_out = Chip.eg_timer;
+				eg_cnt_out = Chip.eg_cnt;
+			}
+		}
+
+		Chip.lfo_am_cnt = lfo_am_cnt_out;
+		Chip.eg_timer = eg_timer_out;
+		Chip.eg_cnt = eg_cnt_out;
+
+		if (rhythm)		/* Rhythm part */
+		{
+			Chip.lfo_am_cnt = lfo_am_cnt_bak;
+			Chip.eg_timer = eg_timer_bak;
+			Chip.eg_cnt = eg_cnt_bak;
+			CalcRhythm (&WorkTable, &Chip, buffer, length);
+		}
+	}
+
+	void UpdateS(short *buffer, int length)
+	{
+		int i;
+
+		uint8_t		rhythm = Chip.rhythm&0x20;
+
+		uint32_t lfo_am_cnt_bak = Chip.lfo_am_cnt;
+		uint32_t eg_timer_bak = Chip.eg_timer;
+		uint32_t eg_cnt_bak = Chip.eg_cnt;
+
+		uint32_t lfo_am_cnt_out = lfo_am_cnt_bak;
+		uint32_t eg_timer_out = eg_timer_bak;
+		uint32_t eg_cnt_out = eg_cnt_bak;
+
+		for (i = 0; i <= (rhythm ? 5 : 8); ++i)
+		{
+			Chip.lfo_am_cnt = lfo_am_cnt_bak;
+			Chip.eg_timer = eg_timer_bak;
+			Chip.eg_cnt = eg_cnt_bak;
+			if (CalcVoice (&WorkTable, &Chip, i, buffer, length))
+			{
+				lfo_am_cnt_out = Chip.lfo_am_cnt;
+				eg_timer_out = Chip.eg_timer;
+				eg_cnt_out = Chip.eg_cnt;
+			}
+		}
+
+		Chip.lfo_am_cnt = lfo_am_cnt_out;
+		Chip.eg_timer = eg_timer_out;
+		Chip.eg_cnt = eg_cnt_out;
+
+		if (rhythm)		/* Rhythm part */
+		{
+			Chip.lfo_am_cnt = lfo_am_cnt_bak;
+			Chip.eg_timer = eg_timer_bak;
+			Chip.eg_cnt = eg_cnt_bak;
+			CalcRhythm (&WorkTable, &Chip, buffer, length);
+		}
+	}
+
+	std::string GetVoiceString(void *chip)
+	{
+		FM_OPL *OPL = (FM_OPL *)chip;
+		char out[9*3];
+
+		for (int i = 0; i <= 8; ++i)
+		{
+			int color;
+
+			if (OPL != NULL && (OPL->P_CH[i].SLOT[0].state != EG_OFF || OPL->P_CH[i].SLOT[1].state != EG_OFF))
+			{
+				color = 'D';	// Green means in use
+			}
+			else
+			{
+				color = 'A';	// Brick means free
+			}
+			out[i*3+0] = '\x1c';
+			out[i*3+1] = color;
+			out[i*3+2] = '*';
+		}
+		return std::string (out, 9*3);
+	}
+};
+
+OPLEmul *YM3812Create(bool stereo)
+{
+	/* emulator create */
+	return new YM3812(stereo);
+}
+
+// [RH] Render a whole voice at once. If nothing else, it lets us avoid
+// wasting a lot of time on voices that aren't playing anything.
+
+static bool CalcVoice (FM_WorkTable *wt, FM_OPL *OPL, int voice, float *buffer, int length)
+{
+	OPL_CH *const CH = &OPL->P_CH[voice];
+	int i;
+
+	if (CH->SLOT[0].state == EG_OFF && CH->SLOT[1].state == EG_OFF)
+	{ // Voice is not playing, so don't do anything for it
+		return false;
+	}
+
+	for (i = 0; i < length; ++i)
+	{
+		advance_lfo(wt, OPL);
+
+		wt->output = 0;
+		float sample = OPL_CALC_CH(wt, CH);
+		if (!OPL->IsStereo)
+		{
+			buffer[i] += sample;
+		}
+		else
+		{
+			buffer[i*2] += sample * CH->LeftVol;
+			buffer[i*2+1] += sample * CH->RightVol;
+		}
+
+		advance(wt, OPL, voice, voice);
+	}
+	return true;
+}
+
+static bool CalcVoice (FM_WorkTable *wt, FM_OPL *OPL, int voice, short *buffer, int length)
+{
+	OPL_CH *const CH = &OPL->P_CH[voice];
+	int i;
+
+	if (CH->SLOT[0].state == EG_OFF && CH->SLOT[1].state == EG_OFF)
+	{ // Voice is not playing, so don't do anything for it
+		return false;
+	}
+
+	for (i = 0; i < length; ++i)
+	{
+		advance_lfo(wt, OPL);
+
+		wt->output = 0;
+		short sample = OPL_CALC_CH_S(wt, CH) / 2;
+
+		if (!OPL->IsStereo)
+		{
+			buffer[i] += sample;
+		}
+		else
+		{
+			buffer[i*2] += sample * CH->LeftVol;
+			buffer[i*2+1] += sample * CH->RightVol;
+		}
+
+		advance(wt, OPL, voice, voice);
+	}
+	return true;
+}
+
+static bool CalcRhythm (FM_WorkTable *wt, FM_OPL *OPL, float *buffer, int length)
+{
+	int i;
+
+	for (i = 0; i < length; ++i)
+	{
+		advance_lfo(wt, OPL);
+
+		wt->output = 0;
+		OPL_CALC_RH(wt, &OPL->P_CH[0], OPL->noise_rng & 1);
+		/* [RH] Convert to floating point. */
+		float sample = float(wt->output) / 10240;
+		if (!OPL->IsStereo)
+		{
+			buffer[i] += sample;
+		}
+		else
+		{
+			// [RH] Always use center panning for rhythm.
+			// The MIDI player doesn't use the rhythm section anyway.
+			buffer[i*2] += sample * CENTER_PANNING_POWER;
+			buffer[i*2+1] += sample * CENTER_PANNING_POWER;
+		}
+
+		advance(wt, OPL, 6, 8);
+		advance_noise(OPL);
+	}
+	return true;
+}
+
+static bool CalcRhythm (FM_WorkTable *wt, FM_OPL *OPL, short *buffer, int length)
+{
+	int i;
+
+	for (i = 0; i < length; ++i)
+	{
+		advance_lfo(wt, OPL);
+
+		wt->output = 0;
+		OPL_CALC_RH(wt, &OPL->P_CH[0], OPL->noise_rng & 1);
+
+		if (!OPL->IsStereo)
+		{
+			buffer[i] += wt->output / 2;
+		}
+		else
+		{
+			// [RH] Always use center panning for rhythm.
+			// The MIDI player doesn't use the rhythm section anyway.
+			buffer[i*2] += (wt->output / 2) * CENTER_PANNING_POWER;
+			buffer[i*2+1] += (wt->output / 2) * CENTER_PANNING_POWER;
+		}
+
+		advance(wt, OPL, 6, 8);
+		advance_noise(OPL);
+	}
+	return true;
+}
diff --git a/src/chips/mame/opl.h b/src/chips/mame/opl.h
new file mode 100644
index 0000000..a1d7184
--- /dev/null
+++ b/src/chips/mame/opl.h
@@ -0,0 +1,27 @@
+#ifndef OPL_H
+#define OPL_H
+
+// Abstract base class for OPL emulators
+
+class OPLEmul
+{
+public:
+	OPLEmul() {}
+	virtual ~OPLEmul() {}
+
+	virtual void Reset() = 0;
+	virtual void WriteReg(int reg, int v) = 0;
+	virtual void Update(float *buffer, int length) = 0;
+	virtual void UpdateS(short *buffer, int length) = 0;
+	virtual void SetPanning(int c, float left, float right) = 0;
+};
+
+OPLEmul *YM3812Create(bool stereo);
+
+#define OPL_SAMPLE_RATE			49716.0
+#define CENTER_PANNING_POWER	0.70710678118	/* [RH] volume at center for EQP */
+#define ADLIB_CLOCK_MUL			24.0
+
+
+
+#endif
diff --git a/src/chips/mame_opl2.cpp b/src/chips/mame_opl2.cpp
new file mode 100644
index 0000000..0b765de
--- /dev/null
+++ b/src/chips/mame_opl2.cpp
@@ -0,0 +1,79 @@
+/*
+ * Interfaces over Yamaha OPL3 (ym3812) chip emulators
+ *
+ * Copyright (c) 2017-2025 Vitaly Novichkov (Wohlstand)
+ *
+ * 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
+ */
+
+#include "mame_opl2.h"
+#include "mame/opl.h"
+#include <cstring>
+
+MameOPL2::MameOPL2() :
+    OPLChipBaseT()
+{
+    m_chip = YM3812Create(false);
+    setRate(m_rate);
+}
+
+MameOPL2::~MameOPL2()
+{
+    OPLEmul *chip_r = reinterpret_cast<OPLEmul*>(m_chip);
+    delete chip_r;
+}
+
+void MameOPL2::setRate(uint32_t rate)
+{
+    OPLChipBaseT::setRate(rate);
+    OPLEmul *chip_r = reinterpret_cast<OPLEmul*>(m_chip);
+    chip_r->Reset();
+}
+
+void MameOPL2::reset()
+{
+    OPLChipBaseT::reset();
+    OPLEmul *chip_r = reinterpret_cast<OPLEmul*>(m_chip);
+    chip_r->Reset();
+}
+
+void MameOPL2::writeReg(uint16_t addr, uint8_t data)
+{
+    OPLEmul *chip_r = reinterpret_cast<OPLEmul*>(m_chip);
+    chip_r->WriteReg(addr, data);
+}
+
+void MameOPL2::nativeGenerate(int16_t *frame)
+{
+    OPLEmul *chip_r = reinterpret_cast<OPLEmul*>(m_chip);
+    frame[0] = 0;
+    chip_r->UpdateS(frame, 1);
+    frame[1] = frame[0];
+}
+
+const char *MameOPL2::emulatorName()
+{
+    return "MAME OPL2";
+}
+
+bool MameOPL2::hasFullPanning()
+{
+    return false;
+}
+
+OPLChipBase::ChipType MameOPL2::chipType()
+{
+    return CHIPTYPE_OPL2;
+}
diff --git a/src/chips/mame_opl2.h b/src/chips/mame_opl2.h
new file mode 100644
index 0000000..8a5ea9c
--- /dev/null
+++ b/src/chips/mame_opl2.h
@@ -0,0 +1,46 @@
+/*
+ * Interfaces over Yamaha OPL3 (YMF262) chip emulators
+ *
+ * Copyright (c) 2017-2025 Vitaly Novichkov (Wohlstand)
+ *
+ * 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
+ */
+
+#ifndef MAME_OPL2_H
+#define MAME_OPL2_H
+
+#include "opl_chip_base.h"
+
+class MameOPL2 final : public OPLChipBaseT<MameOPL2>
+{
+    void *m_chip;
+
+public:
+    MameOPL2();
+    ~MameOPL2() override;
+
+    bool canRunAtPcmRate() const override { return false; }
+    void setRate(uint32_t rate) override;
+    void reset() override;
+    void writeReg(uint16_t addr, uint8_t data) override;
+    void nativePreGenerate() override {}
+    void nativePostGenerate() override {}
+    void nativeGenerate(int16_t *frame) override;
+    const char *emulatorName() override;
+    ChipType chipType() override;
+    bool hasFullPanning() override;
+};
+
+#endif // MAME_OPL2_H
diff --git a/utils/midiplay/adlmidiplay.cpp b/utils/midiplay/adlmidiplay.cpp
index e0bbdde..0e60e8e 100644
--- a/utils/midiplay/adlmidiplay.cpp
+++ b/utils/midiplay/adlmidiplay.cpp
@@ -1430,6 +1430,8 @@ int main(int argc, char **argv)
             emulator = ADLMIDI_EMU_JAVA;
         else if(!std::strcmp("--emu-esfmu", argv[2]))
             emulator = ADLMIDI_EMU_ESFMu;
+        else if(!std::strcmp("--emu-mame-opl2", argv[2]))
+            emulator = ADLMIDI_EMU_MAME_OPL2;
         else if(!std::strcmp("--emu-ymfm-opl2", argv[2]))
             emulator = ADLMIDI_EMU_YMFM_OPL2;
         else if(!std::strcmp("--emu-ymfm-opl3", argv[2]))
diff --git a/utils/vlc_codec/libadlmidi.c b/utils/vlc_codec/libadlmidi.c
index 1ef1387..ca56245 100644
--- a/utils/vlc_codec/libadlmidi.c
+++ b/utils/vlc_codec/libadlmidi.c
@@ -165,6 +165,7 @@ static const char * const emulator_type_descriptions[] =
     N_("Opal"),
     N_("Java OPL3"),
     N_("ESFMu"),
+    N_("MAME OPL2"),
 #ifndef ADLMIDI_DISABLE_YMFM_EMULATOR
     N_("YMFM OPL2"),
     N_("YMFM OPL3"),
diff --git a/utils/winmm_drv/cpl/config_dialog.c b/utils/winmm_drv/cpl/config_dialog.c
index abaa857..62a308d 100644
--- a/utils/winmm_drv/cpl/config_dialog.c
+++ b/utils/winmm_drv/cpl/config_dialog.c
@@ -56,6 +56,7 @@ static const char * const emulator_type_descriptions[] =
     "Opal",
     "Java OPL3",
     "ESFMu",
+    "MAME OPL2",
 #ifndef ADLMIDI_DISABLE_YMFM_EMULATOR
     "YMFM OPL2",
     "YMFM OPL3",