/*
 * Rockbox notes:
 *
 * This file is originally from the MAME project, from after their
 * GPLv2 relicense. I (Franklin Wei) have made some modifications
 * since then to make it work with the Wolf4SDL source. Notably, I
 * corrected the behavior of YM3812Write() to write directly to the
 * registers. Additionally, I fixed an unaligned write in OPL_CALC_CH
 * which caused terrible output on ARM.
 */

// license:GPL-2.0+
// copyright-holders:Jarek Burczynski,Tatsuyuki Satoh
/*
**
** 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 "fmopl.h"

// Don't pack structs in here. This causes dangerous things on ARM
// regarding alignment.
#pragma pack()

/* output final shift */
#if (OPL_SAMPLE_BITS==16)
#define FINAL_SH    (0)
#define MAXOUT      (+32767)
#define MINOUT      (-32768)
#else
#define FINAL_SH    (8)
#define MAXOUT      (+127)
#define MINOUT      (-128)
#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


/* save output as raw 16-bit sample */

/*#define SAVE_SAMPLE*/

#ifdef SAVE_SAMPLE
static signed int acc_calc(signed int value)
{
    if (value>=0)
    {
        if (value < 0x0200)
            return (value & ~0);
        if (value < 0x0400)
            return (value & ~1);
        if (value < 0x0800)
            return (value & ~3);
        if (value < 0x1000)
            return (value & ~7);
        if (value < 0x2000)
            return (value & ~15);
        if (value < 0x4000)
            return (value & ~31);
        return (value & ~63);
    }
    /*else value < 0*/
    if (value > -0x0200)
        return (~abs(value) & ~0);
    if (value > -0x0400)
        return (~abs(value) & ~1);
    if (value > -0x0800)
        return (~abs(value) & ~3);
    if (value > -0x1000)
        return (~abs(value) & ~7);
    if (value > -0x2000)
        return (~abs(value) & ~15);
    if (value > -0x4000)
        return (~abs(value) & ~31);
    return (~abs(value) & ~63);
}


static FILE *sample[1];
#if 1   /*save to MONO file */
#define SAVE_ALL_CHANNELS                               \
    {   signed int pom = acc_calc(lt);                  \
        fputc((unsigned short)pom&0xff,sample[0]);      \
        fputc(((unsigned short)pom>>8)&0xff,sample[0]); \
    }
#else   /*save to STEREO file */
#define SAVE_ALL_CHANNELS                               \
    {   signed int pom = lt;                            \
        fputc((unsigned short)pom&0xff,sample[0]);      \
        fputc(((unsigned short)pom>>8)&0xff,sample[0]); \
        pom = rt;                                       \
        fputc((unsigned short)pom&0xff,sample[0]);      \
        fputc(((unsigned short)pom>>8)&0xff,sample[0]); \
    }
#endif
#endif

#define LOG_CYM_FILE 0
static FILE * cymfile = NULL;



#define OPL_TYPE_WAVESEL   0x01  /* waveform select     */
#define OPL_TYPE_ADPCM     0x02  /* DELTA-T ADPCM unit  */
#define OPL_TYPE_KEYBOARD  0x04  /* keyboard interface  */
#define OPL_TYPE_IO        0x08  /* I/O port            */

/* ---------- Generic interface section ---------- */
#define OPL_TYPE_YM3526 (0)
#define OPL_TYPE_YM3812 (OPL_TYPE_WAVESEL)
#define OPL_TYPE_Y8950  (OPL_TYPE_ADPCM|OPL_TYPE_KEYBOARD|OPL_TYPE_IO)

struct OPL_SLOT
{
    UINT32  ar;         /* attack rate: AR<<2           */
    UINT32  dr;         /* decay rate:  DR<<2           */
    UINT32  rr;         /* release rate:RR<<2           */
    UINT8   KSR;        /* key scale rate               */
    UINT8   ksl;        /* keyscale level               */
    UINT8   ksr;        /* key scale rate: kcode>>KSR   */
    UINT8   mul;        /* multiple: mul_tab[ML]        */

    /* Phase Generator */
    UINT32  Cnt;        /* frequency counter            */
    UINT32  Incr;       /* frequency counter step       */
    UINT8   FB;         /* feedback shift value         */
    INT32   *connect1;  /* slot1 output pointer         */
    INT32   op1_out[2]; /* slot1 output for feedback    */
    UINT8   CON;        /* connection (algorithm) type  */

    /* Envelope Generator */
    UINT8   eg_type;    /* percussive/non-percussive mode */
    UINT8   state;      /* phase type                   */
    UINT32  TL;         /* total level: TL << 2         */
    INT32   TLL;        /* adjusted now TL              */
    INT32   volume;     /* envelope counter             */
    UINT32  sl;         /* sustain level: sl_tab[SL]    */
    UINT8   eg_sh_ar;   /* (attack state)               */
    UINT8   eg_sel_ar;  /* (attack state)               */
    UINT8   eg_sh_dr;   /* (decay state)                */
    UINT8   eg_sel_dr;  /* (decay state)                */
    UINT8   eg_sh_rr;   /* (release state)              */
    UINT8   eg_sel_rr;  /* (release state)              */
    UINT32  key;        /* 0 = KEY OFF, >0 = KEY ON     */

    /* LFO */
    UINT32  AMmask;     /* LFO Amplitude Modulation enable mask */
    UINT8   vib;        /* LFO Phase Modulation enable flag (active high)*/

    /* waveform select */
    UINT16  wavetable;
};

typedef struct OPL_SLOT OPL_SLOT;

struct OPL_CH
{
    OPL_SLOT SLOT[2];
    /* phase generator state */
    UINT32  block_fnum; /* block+fnum                   */
    UINT32  fc;         /* Freq. Increment base         */
    UINT32  ksl_base;   /* KeyScaleLevel Base step      */
    UINT8   kcode;      /* key code (for key scaling)   */
};

typedef struct OPL_CH OPL_CH;

/* OPL state */
struct FM_OPL
{
    /* FM channel slots */
    OPL_CH  P_CH[9];                /* OPL/OPL2 chips have 9 channels*/

    UINT32  eg_cnt;                 /* global envelope generator counter    */
    UINT32  eg_timer;               /* global envelope generator counter works at frequency = chipclock/72 */
    UINT32  eg_timer_add;           /* step of eg_timer                     */
    UINT32  eg_timer_overflow;      /* envelope generator timer overlfows every 1 sample (on real chip) */

    UINT8   rhythm;                 /* Rhythm mode                  */

    UINT32  fn_tab[1024];           /* fnumber->increment counter   */

    /* LFO */
    UINT32  LFO_AM;
    INT32   LFO_PM;

    UINT8   lfo_am_depth;
    UINT8   lfo_pm_depth_range;
    UINT32  lfo_am_cnt;
    UINT32  lfo_am_inc;
    UINT32  lfo_pm_cnt;
    UINT32  lfo_pm_inc;

    UINT32  noise_rng;              /* 23 bit noise shift register  */
    UINT32  noise_p;                /* current noise 'phase'        */
    UINT32  noise_f;                /* current noise period         */

    UINT8   wavesel;                /* waveform select enable flag  */

    UINT32  T[2];                   /* timer counters               */
    UINT8   st[2];                  /* timer enable                 */

#if BUILD_Y8950
    /* Delta-T ADPCM unit (Y8950) */

    YM_DELTAT *deltat;

    /* Keyboard and I/O ports interface */
    UINT8   portDirection;
    UINT8   portLatch;
    OPL_PORTHANDLER_R porthandler_r;
    OPL_PORTHANDLER_W porthandler_w;
    void *  port_param;
    OPL_PORTHANDLER_R keyboardhandler_r;
    OPL_PORTHANDLER_W keyboardhandler_w;
    void *  keyboard_param;
#endif

    /* external event callback handlers */
    OPL_TIMERHANDLER  timer_handler;    /* TIMER handler                */
    void *TimerParam;                   /* TIMER parameter              */
    OPL_IRQHANDLER    IRQHandler;   /* IRQ handler                  */
    void *IRQParam;                 /* IRQ parameter                */
    OPL_UPDATEHANDLER UpdateHandler;/* stream update handler        */
    void *UpdateParam;              /* stream update parameter      */
    UINT8 type;                     /* chip type                    */
    UINT8 address;                  /* address register             */
    UINT8 status;                   /* status flag                  */
    UINT8 statusmask;               /* status mask                  */
    UINT8 mode;                     /* Reg.08 : CSM,notesel,etc.    */

    UINT32 clock;                   /* master clock  (Hz)           */
    UINT32 rate;                    /* sampling rate (Hz)           */
    double freqbase;                /* frequency base               */
    double TimerBase;         /* Timer base time (==sampling time)*/
    device_t *device;

    signed int phase_modulation;    /* phase modulation input (SLOT 2) */
    signed int output[1];

#if BUILD_Y8950
    INT32 output_deltat[4];     /* for Y8950 DELTA-T, chip is mono, that 4 here is just for safety */
#endif
};

typedef struct FM_OPL FM_OPL;

/* 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 ksl_tab[8*16]=
{
    /* OCT 0 */
    0.000/DV, 0.000/DV, 0.000/DV, 0.000/DV,
    0.000/DV, 0.000/DV, 0.000/DV, 0.000/DV,
    0.000/DV, 0.000/DV, 0.000/DV, 0.000/DV,
    0.000/DV, 0.000/DV, 0.000/DV, 0.000/DV,
    /* OCT 1 */
    0.000/DV, 0.000/DV, 0.000/DV, 0.000/DV,
    0.000/DV, 0.000/DV, 0.000/DV, 0.000/DV,
    0.000/DV, 0.750/DV, 1.125/DV, 1.500/DV,
    1.875/DV, 2.250/DV, 2.625/DV, 3.000/DV,
    /* OCT 2 */
    0.000/DV, 0.000/DV, 0.000/DV, 0.000/DV,
    0.000/DV, 1.125/DV, 1.875/DV, 2.625/DV,
    3.000/DV, 3.750/DV, 4.125/DV, 4.500/DV,
    4.875/DV, 5.250/DV, 5.625/DV, 6.000/DV,
    /* OCT 3 */
    0.000/DV, 0.000/DV, 0.000/DV, 1.875/DV,
    3.000/DV, 4.125/DV, 4.875/DV, 5.625/DV,
    6.000/DV, 6.750/DV, 7.125/DV, 7.500/DV,
    7.875/DV, 8.250/DV, 8.625/DV, 9.000/DV,
    /* OCT 4 */
    0.000/DV, 0.000/DV, 3.000/DV, 4.875/DV,
    6.000/DV, 7.125/DV, 7.875/DV, 8.625/DV,
    9.000/DV, 9.750/DV,10.125/DV,10.500/DV,
    10.875/DV,11.250/DV,11.625/DV,12.000/DV,
    /* OCT 5 */
    0.000/DV, 3.000/DV, 6.000/DV, 7.875/DV,
    9.000/DV,10.125/DV,10.875/DV,11.625/DV,
    12.000/DV,12.750/DV,13.125/DV,13.500/DV,
    13.875/DV,14.250/DV,14.625/DV,15.000/DV,
    /* OCT 6 */
    0.000/DV, 6.000/DV, 9.000/DV,10.875/DV,
    12.000/DV,13.125/DV,13.875/DV,14.625/DV,
    15.000/DV,15.750/DV,16.125/DV,16.500/DV,
    16.875/DV,17.250/DV,17.625/DV,18.000/DV,
    /* OCT 7 */
    0.000/DV, 9.000/DV,12.000/DV,13.875/DV,
    15.000/DV,16.125/DV,16.875/DV,17.625/DV,
    18.000/DV,18.750/DV,19.125/DV,19.500/DV,
    19.875/DV,20.250/DV,20.625/DV,21.000/DV
};
#undef DV

/* 0 / 3.0 / 1.5 / 6.0 dB/OCT */
static const UINT32 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) ( db * (2.0/ENV_STEP) )
static const UINT32 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 mul_tab[16]= {
/* 1/2, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,10,12,12,15,15 */
    ML/2, 1*ML, 2*ML, 3*ML, 4*ML, 5*ML, 6*ML, 7*ML,
    8*ML, 9*ML,10*ML,10*ML,12*ML,12*ML,15*ML,15*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 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 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*/
};


/* lock level of common table */
static int num_lock = 0;


#define SLOT7_1 (&OPL->P_CH[7].SLOT[SLOT1])
#define SLOT7_2 (&OPL->P_CH[7].SLOT[SLOT2])
#define SLOT8_1 (&OPL->P_CH[8].SLOT[SLOT1])
#define SLOT8_2 (&OPL->P_CH[8].SLOT[SLOT2])




static int limit( int val, int max, int min ) {
    if ( val > max )
        val = max;
    else if ( val < min )
        val = min;

    return val;
}


/* status set and IRQ handling */
static 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;
            /* callback user interrupt handler (IRQ is OFF to ON) */
            if(OPL->IRQHandler) (OPL->IRQHandler)(OPL->IRQParam,1);
        }
    }
}

/* status reset and IRQ handling */
static 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;
            /* callback user interrupt handler (IRQ is ON to OFF) */
            if(OPL->IRQHandler) (OPL->IRQHandler)(OPL->IRQParam,0);
        }
    }
}

/* IRQ mask set */
static 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 void advance_lfo(FM_OPL *OPL)
{
    UINT8 tmp;

    /* LFO */
    OPL->lfo_am_cnt += OPL->lfo_am_inc;
//	if (OPL->lfo_am_cnt >= ((UINT32)LFO_AM_TAB_ELEMENTS<<LFO_SH) )  /* lfo_am_table is 210 elements long */
//		OPL->lfo_am_cnt -= ((UINT32)LFO_AM_TAB_ELEMENTS<<LFO_SH);
    if (OPL->lfo_am_cnt >= (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)
        OPL->LFO_AM = tmp;
    else
        OPL->LFO_AM = tmp>>2;

    OPL->lfo_pm_cnt += OPL->lfo_pm_inc;
    OPL->LFO_PM = ((OPL->lfo_pm_cnt>>LFO_SH) & 7) | OPL->lfo_pm_depth_range;
}

/* advance to next sample */
static void advance(FM_OPL *OPL)
{
    OPL_CH *CH;
    OPL_SLOT *op;
    int i;

    OPL->eg_timer += OPL->eg_timer_add;

    while (OPL->eg_timer >= OPL->eg_timer_overflow)
    {
        OPL->eg_timer -= OPL->eg_timer_overflow;

        OPL->eg_cnt++;

        for (i=0; i<9*2; 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 ( (UINT32) op->volume >= 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;
            }
        }
    }

    for (i=0; i<9*2; i++)
    {
        CH  = &OPL->P_CH[i/2];
        op  = &CH->SLOT[i&1];

        /* Phase Generator */
        if(op->vib)
        {
            UINT8 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[OPL->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;
        }
    }

    /*  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 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 signed int op_calc(UINT32 phase, unsigned int env, signed int pm, unsigned int wave_tab)
{
    UINT32 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 signed int op_calc1(UINT32 phase, unsigned int env, signed int pm, unsigned int wave_tab)
{
    UINT32 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)(OP)->volume) + (OPL->LFO_AM & (OP)->AMmask))

/* calculate output */
static void OPL_CALC_CH( FM_OPL *OPL, OPL_CH *CH )
{
    OPL_SLOT *SLOT;
    unsigned int env;
    signed int out;

    OPL->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];

    //INT32 a;
    //memcpy(&a, SLOT->connect1, sizeof(a));
    //a += SLOT->op1_out[0];
    //memcpy(SLOT->connect1, &a, sizeof(a));

    *SLOT->connect1 += SLOT->op1_out[0]; // alignment issue on arm
    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 )
    {
        OPL->output[0] += op_calc(SLOT->Cnt, env, OPL->phase_modulation, SLOT->wavetable);
    }
}

/*
  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 void OPL_CALC_RH( FM_OPL *OPL, 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
    */

    OPL->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)
        OPL->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 )
        OPL->output[0] += op_calc(SLOT->Cnt, env, OPL->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(SLOT7_1);
    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 = ((SLOT7_1->Cnt>>FREQ_SH)>>7)&1;
        unsigned char bit3 = ((SLOT7_1->Cnt>>FREQ_SH)>>3)&1;
        unsigned char bit2 = ((SLOT7_1->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 phase = res1 ? (0x200|(0xd0>>2)) : 0xd0;

        /* enable gate based on frequency of operator 2 in channel 8 */
        unsigned char bit5e= ((SLOT8_2->Cnt>>FREQ_SH)>>5)&1;
        unsigned char bit3e= ((SLOT8_2->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;
        }

        OPL->output[0] += op_calc(phase<<FREQ_SH, env, 0, SLOT7_1->wavetable) * 2;
    }

    /* Snare Drum (verified on real YM3812) */
    env = volume_calc(SLOT7_2);
    if( env < ENV_QUIET )
    {
        /* base frequency derived from operator 1 in channel 7 */
        unsigned char bit8 = ((SLOT7_1->Cnt>>FREQ_SH)>>8)&1;

        /* when bit8 = 0 phase = 0x100; */
        /* when bit8 = 1 phase = 0x200; */
        UINT32 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;

        OPL->output[0] += op_calc(phase<<FREQ_SH, env, 0, SLOT7_2->wavetable) * 2;
    }

    /* Tom Tom (verified on real YM3812) */
    env = volume_calc(SLOT8_1);
    if( env < ENV_QUIET )
        OPL->output[0] += op_calc(SLOT8_1->Cnt, env, 0, SLOT8_1->wavetable) * 2;

    /* Top Cymbal (verified on real YM3812) */
    env = volume_calc(SLOT8_2);
    if( env < ENV_QUIET )
    {
        /* base frequency derived from operator 1 in channel 7 */
        unsigned char bit7 = ((SLOT7_1->Cnt>>FREQ_SH)>>7)&1;
        unsigned char bit3 = ((SLOT7_1->Cnt>>FREQ_SH)>>3)&1;
        unsigned char bit2 = ((SLOT7_1->Cnt>>FREQ_SH)>>2)&1;

        unsigned char res1 = (bit2 ^ bit7) | bit3;

        /* when res1 = 0 phase = 0x000 | 0x100; */
        /* when res1 = 1 phase = 0x200 | 0x100; */
        UINT32 phase = res1 ? 0x300 : 0x100;

        /* enable gate based on frequency of operator 2 in channel 8 */
        unsigned char bit5e= ((SLOT8_2->Cnt>>FREQ_SH)>>5)&1;
        unsigned char bit3e= ((SLOT8_2->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;

        OPL->output[0] += op_calc(phase<<FREQ_SH, env, 0, SLOT8_2->wavetable) * 2;
    }
}


/* generic table initialize */
static int init_tables(void)
{
    signed int i,x;
    signed int n;
    double o,m;


    for (x=0; x<TL_RES_LEN; x++)
    {
        m = (1<<16) / pow(2, (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 */
        if (n&1)        /* round to nearest */
            n = (n>>1)+1;
        else
            n = n>>1;
        /* 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*2*TL_RES_LEN ];
        }
#if 0
        logerror("tl %04i", x*2);
        for (i=0; i<12; i++)
            logerror(", [%02i] %5i", i*2, tl_tab[ x*2 /*+1*/ + i*2*TL_RES_LEN ] );
        logerror("\n");
#endif
    }
    /*logerror("FMOPL.C: TL_TAB_LEN = %i elements (%i bytes)\n",TL_TAB_LEN, (int)sizeof(tl_tab));*/


    for (i=0; i<SIN_LEN; i++)
    {
        /* non-standard sinus */
        m = sin( ((i*2)+1) * M_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 );

        /*logerror("FMOPL.C: sin [%4i (hex=%03x)]= %4i (tl_tab value=%5i)\n", i, i, sin_tab[i], tl_tab[sin_tab[i]] );*/
    }

    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)];

            /*logerror("FMOPL.C: sin1[%4i]= %4i (tl_tab value=%5i)\n", i, sin_tab[1*SIN_LEN+i], tl_tab[sin_tab[1*SIN_LEN+i]] );
              logerror("FMOPL.C: sin2[%4i]= %4i (tl_tab value=%5i)\n", i, sin_tab[2*SIN_LEN+i], tl_tab[sin_tab[2*SIN_LEN+i]] );
              logerror("FMOPL.C: sin3[%4i]= %4i (tl_tab value=%5i)\n", i, sin_tab[3*SIN_LEN+i], tl_tab[sin_tab[3*SIN_LEN+i]] );*/
    }
    /*logerror("FMOPL.C: ENV_QUIET= %08x (dec*8=%i)\n", ENV_QUIET, ENV_QUIET*8 );*/


#ifdef SAVE_SAMPLE
    sample[0]=fopen("sampsum.pcm","wb");
#endif

    return 1;
}

static void OPLCloseTable( void )
{
#ifdef SAVE_SAMPLE
    fclose(sample[0]);
#endif
}



static void OPL_initalize(FM_OPL *OPL)
{
    int i;

    /* frequency base */
    OPL->freqbase  = (OPL->rate) ? ((double)OPL->clock / 72.0) / OPL->rate  : 0;
#if 0
    OPL->rate = (double)OPL->clock / 72.0;
    OPL->freqbase  = 1.0;
#endif

    /*logerror("freqbase=%f\n", OPL->freqbase);*/

    /* Timer base time */
    OPL->TimerBase = 1.0 / ((double)OPL->clock / 72.0 );

    /* make fnumber -> increment counter table */
    for( i=0 ; i < 1024 ; i++ )
    {
        /* opn phase increment counter = 20bit */
        OPL->fn_tab[i] = (UINT32)( (double)i * 64 * OPL->freqbase * (1<<(FREQ_SH-10)) ); /* -10 because chip works with 10.10 fixed point, while we use 16.16 */
#if 0
        logerror("FMOPL.C: fn_tab[%4i] = %08x (dec=%8i)\n",
                 i, OPL->fn_tab[i]>>6, OPL->fn_tab[i]>>6 );
#endif
    }

#if 0
    for( i=0 ; i < 16 ; i++ )
    {
        logerror("FMOPL.C: sl_tab[%i] = %08x\n",
                 i, sl_tab[i] );
    }
    for( i=0 ; i < 8 ; i++ )
    {
        int j;
        logerror("FMOPL.C: ksl_tab[oct=%2i] =",i);
        for (j=0; j<16; j++)
        {
            logerror("%08x ", (UINT32)(ksl_tab[i*16+j]) );
        }
        logerror("\n");
    }
#endif


    /* 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) ((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) ((1.0 / 1024.0) * (1<<LFO_SH) * OPL->freqbase);

    /*logerror ("OPL->lfo_am_inc = %8x ; OPL->lfo_pm_inc = %8x\n", OPL->lfo_am_inc, OPL->lfo_pm_inc);*/

    /* Noise generator: a step takes 1 sample */
    OPL->noise_f = (UINT32) ((1.0 / 1.0) * (1<<FREQ_SH) * OPL->freqbase);

    OPL->eg_timer_add = (UINT32) ((1<<EG_SH) * OPL->freqbase);
    OPL->eg_timer_overflow = ( 1 ) * (1<<EG_SH);
    /*logerror("OPLinit eg_timer_add=%8x eg_timer_overflow=%8x\n", OPL->eg_timer_add, OPL->eg_timer_overflow);*/

}

static void FM_KEYON(OPL_SLOT *SLOT, UINT32 key_set)
{
    if( !SLOT->key )
    {
        /* restart Phase Generator */
        SLOT->Cnt = 0;
        /* phase -> Attack */
        SLOT->state = EG_ATT;
    }
    SLOT->key |= key_set;
}

static void FM_KEYOFF(OPL_SLOT *SLOT, UINT32 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 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 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 void set_ksl_tl(FM_OPL *OPL,int slot,int v)
{
#if 0
    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);
#else
    OPL_CH   *CH   = &OPL->P_CH[slot/2];
    OPL_SLOT *SLOT = &CH->SLOT[slot&1];
    int ksl = v>>6; /* 0 / 1.5 / 3.0 / 6.0 dB/OCT */

    SLOT->ksl = ksl ? 3-ksl : 31;
    SLOT->TL  = (v&0x3f)<<(ENV_BITS-1-7); /* 7 bits TL (bit 6 = always 0) */

    SLOT->TLL = SLOT->TL + (CH->ksl_base>>SLOT->ksl);
#endif
}

/* set attack rate & decay rate  */
static 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 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 OPLWriteReg(FM_OPL *OPL, int r, int v)
{
    OPL_CH *CH;
    int slot;
    int block_fnum;


    /* adjust bus to 8 bits */
    r &= 0xff;
    v &= 0xff;

    if (LOG_CYM_FILE && (cymfile) && (r!=0) )
    {
        fprintf(cymfile, "%02x = %02x\n", r, v);
    }


    switch(r&0xe0)
    {
    case 0x00:  /* 00-1f:control */
        switch(r&0x1f)
        {
        case 0x01:  /* waveform select enable */
            if(OPL->type&OPL_TYPE_WAVESEL)
            {
                OPL->wavesel = v&0x20;
                /* do not change the waveform previously selected */
            }
            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 st1 = v&1;
                UINT8 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)
                {
                    double period = st2 ? (double)OPL->T[1]*OPL->TimerBase : 0.0;
                    //double period = st2 ? (OPL->TimerBase * OPL->T[1]) : 0;
                    OPL->st[1] = st2;
                    if (OPL->timer_handler) (OPL->timer_handler)(1,period);
                }
                /* timer 1 */
                if(OPL->st[0] != st1)
                {
                    double period = st1 ? (double)OPL->T[0]*OPL->TimerBase : 0.0;
                    //double period = st1 ? (OPL->TimerBase * OPL->T[0]) : 0;
                    OPL->st[0] = st1;
                    if (OPL->timer_handler) (OPL->timer_handler)(0,period);
                }
            }
            break;
#if BUILD_Y8950
        case 0x06:      /* Key Board OUT */
            if(OPL->type&OPL_TYPE_KEYBOARD)
            {
                if(OPL->keyboardhandler_w)
                    OPL->keyboardhandler_w(OPL->keyboard_param,v);
                else
                {
                    //OPL->device->logerror("Y8950: write unmapped KEYBOARD port\n");
                }
            }
            break;
        case 0x07:  /* DELTA-T control 1 : START,REC,MEMDATA,REPT,SPOFF,x,x,RST */
            if(OPL->type&OPL_TYPE_ADPCM)
                YM_DELTAT_ADPCM_Write(OPL->deltat,r-0x07,v);
            break;
#endif
        case 0x08:  /* MODE,DELTA-T control 2 : CSM,NOTESEL,x,x,smpl,da/ad,64k,rom */
            OPL->mode = v;
#if BUILD_Y8950
            if(OPL->type&OPL_TYPE_ADPCM)
                YM_DELTAT_ADPCM_Write(OPL->deltat,r-0x07,v&0x0f); /* mask 4 LSBs in register 08 for DELTA-T unit */
#endif
            break;

#if BUILD_Y8950
        case 0x09:      /* START ADD */
        case 0x0a:
        case 0x0b:      /* STOP ADD  */
        case 0x0c:
        case 0x0d:      /* PRESCALE   */
        case 0x0e:
        case 0x0f:      /* ADPCM data write */
        case 0x10:      /* DELTA-N    */
        case 0x11:      /* DELTA-N    */
        case 0x12:      /* ADPCM volume */
            if(OPL->type&OPL_TYPE_ADPCM)
                YM_DELTAT_ADPCM_Write(OPL->deltat,r-0x07,v);
            break;

        case 0x15:      /* DAC data high 8 bits (F7,F6...F2) */
        case 0x16:      /* DAC data low 2 bits (F1, F0 in bits 7,6) */
        case 0x17:      /* DAC data shift (S2,S1,S0 in bits 2,1,0) */
            //OPL->device->logerror("FMOPL.C: DAC data register written, but not implemented reg=%02x val=%02x\n",r,v);
            break;

        case 0x18:      /* I/O CTRL (Direction) */
            if(OPL->type&OPL_TYPE_IO)
                OPL->portDirection = v&0x0f;
            break;
        case 0x19:      /* I/O DATA */
            if(OPL->type&OPL_TYPE_IO)
            {
                OPL->portLatch = v;
                if(OPL->porthandler_w)
                    OPL->porthandler_w(OPL->port_param,v&OPL->portDirection);
            }
            break;
#endif
        default:
            //OPL->device->logerror("FMOPL.C: write to unknown register: %02x\n",r);
            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) block_fnum)
        {
            UINT8 block  = block_fnum >> 10;

            CH->block_fnum = block_fnum;

            CH->ksl_base = (UINT32)(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 ? &OPL->output[0] : &OPL->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 TIMER_CALLBACK( cymfile_callback )
{
    if (cymfile)
    {
        //fputc( (unsigned char)0, cymfile );
    }
}

/* lock/unlock for common table */
static int OPL_LockTable(device_t *device)
{
    num_lock++;
    if(num_lock>1) return 0;

    /* first time */

    /* allocate total level table (128kb space) */
    if( !init_tables() )
    {
        num_lock--;
        return -1;
    }

    if (LOG_CYM_FILE)
    {
        cymfile = fopen("/3812_.cym","w");
        if (cymfile)
        {
            //device->machine().scheduler().timer_pulse ( double::from_hz(110), FUNC(cymfile_callback)); /*110 Hz pulse timer*/
        }
        else
        {
            //device->logerror("Could not create file 3812_.cym\n");
        }
    }

    return 0;
}

static void OPL_UnLockTable(void)
{
    if(num_lock) num_lock--;
    if(num_lock) return;

    /* last time */

    OPLCloseTable();

    if (cymfile)
        fclose (cymfile);
    cymfile = NULL;
}

static void OPLResetChip(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 */
    OPLWriteReg(OPL,0x01,0); /* wavesel disable */
    OPLWriteReg(OPL,0x02,0); /* Timer1 */
    OPLWriteReg(OPL,0x03,0); /* Timer2 */
    OPLWriteReg(OPL,0x04,0); /* IRQ mask clear */
    for(i = 0xff ; i >= 0x20 ; i-- ) OPLWriteReg(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;
        }
    }
#if BUILD_Y8950
    if(OPL->type&OPL_TYPE_ADPCM)
    {
        YM_DELTAT *DELTAT = OPL->deltat;

        DELTAT->freqbase = OPL->freqbase;
        DELTAT->output_pointer = &OPL->output_deltat[0];
        DELTAT->portshift = 5;
        DELTAT->output_range = 1<<23;
        YM_DELTAT_ADPCM_Reset(DELTAT,0,YM_DELTAT_EMULATION_MODE_NORMAL,OPL->device);
    }
#endif
}


static void OPL_postload(FM_OPL *OPL)
{
    int slot, ch;

    for( ch=0 ; ch < 9 ; ch++ )
    {
        OPL_CH *CH = &OPL->P_CH[ch];

        /* Look up key scale level */
        UINT32 block_fnum = CH->block_fnum;
        CH->ksl_base = (UINT32)(ksl_tab[block_fnum >> 6]);
        CH->fc       = OPL->fn_tab[block_fnum & 0x03ff] >> (7 - (block_fnum >> 10));

        for( slot=0 ; slot < 2 ; slot++ )
        {
            OPL_SLOT *SLOT = &CH->SLOT[slot];

            /* Calculate key scale rate */
            SLOT->ksr = CH->kcode >> SLOT->KSR;

            /* Calculate attack, decay and release 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 ];

            /* Calculate phase increment */
            SLOT->Incr = CH->fc * SLOT->mul;

            /* Total level */
            SLOT->TLL = SLOT->TL + (CH->ksl_base >> SLOT->ksl);

            /* Connect output */
            SLOT->connect1 = SLOT->CON ? &OPL->output[0] : &OPL->phase_modulation;
        }
    }
#if BUILD_Y8950
    if ( (OPL->type & OPL_TYPE_ADPCM) && (OPL->deltat) )
    {
        // We really should call the postlod function for the YM_DELTAT, but it's hard without registers
        // (see the way the YM2610 does it)
        //YM_DELTAT_postload(OPL->deltat, REGS);
    }
#endif
}


static void OPLsave_state_channel(device_t *device, OPL_CH *CH)
{
}


/* Register savestate for a virtual YM3812/YM3526Y8950 */

static void OPL_save_state(FM_OPL *OPL, device_t *device)
{
}


/* Create one of virtual YM3812/YM3526/Y8950 */
/* 'clock' is chip clock in Hz  */
/* 'rate'  is sampling rate  */
static FM_OPL *OPLCreate(device_t *device, UINT32 clock, UINT32 rate, int type)
{
    char *ptr;
    FM_OPL *OPL;
    int state_size;

    if (OPL_LockTable(device) == -1) return NULL;

    /* calculate OPL state size */
    state_size  = sizeof(FM_OPL);

#if BUILD_Y8950
    if (type&OPL_TYPE_ADPCM) state_size+= sizeof(YM_DELTAT);
#endif

    /* allocate memory block */
    ptr = malloc(state_size);

    if(!ptr)
        return NULL;

    memset(ptr, 0, state_size);

    OPL  = (FM_OPL *)ptr;

    /* GCC behaves weirdly... check that it's not acting up */

    if((UINT32)OPL & 3 == 0)
        printf("OPL is word-aligned");
    if((UINT32)(OPL->output) & 3 == 0)
        printf("output is word-aligned");

    ptr += sizeof(FM_OPL);

#if BUILD_Y8950
    if (type&OPL_TYPE_ADPCM)
    {
        OPL->deltat = (YM_DELTAT *)ptr;
    }
    ptr += sizeof(YM_DELTAT);
#endif

    OPL->device = device;
    OPL->type  = type;
    OPL->clock = clock;
    OPL->rate  = rate;

    /* init global tables */
    OPL_initalize(OPL);

    return OPL;
}

/* Destroy one of virtual YM3812 */
static void OPLDestroy(FM_OPL *OPL)
{
    OPL_UnLockTable();
    free(OPL);
}

/* Optional handlers */

static void OPLSetTimerHandler(FM_OPL *OPL,OPL_TIMERHANDLER timer_handler,void *param)
{
    OPL->timer_handler   = timer_handler;
    OPL->TimerParam = param;
}
static void OPLSetIRQHandler(FM_OPL *OPL,OPL_IRQHANDLER IRQHandler,void *param)
{
    OPL->IRQHandler     = IRQHandler;
    OPL->IRQParam = param;
}
static void OPLSetUpdateHandler(FM_OPL *OPL,OPL_UPDATEHANDLER UpdateHandler,void *param)
{
    OPL->UpdateHandler = UpdateHandler;
    OPL->UpdateParam = param;
}

static int OPLWrite(FM_OPL *OPL,int a,int v)
{
    if( !(a&1) )
    {   /* address port */
        OPL->address = v & 0xff;
    }
    else
    {   /* data port */
        if(OPL->UpdateHandler) OPL->UpdateHandler(OPL->UpdateParam,0);
        OPLWriteReg(OPL,OPL->address,v);
    }
    return OPL->status>>7;
}

static unsigned char OPLRead(FM_OPL *OPL,int a)
{
    if( !(a&1) )
    {
        /* status port */

#if BUILD_Y8950

        if(OPL->type&OPL_TYPE_ADPCM)    /* Y8950 */
        {
            return (OPL->status & (OPL->statusmask|0x80)) | (OPL->deltat->PCM_BSY&1);
        }

#endif

        /* OPL and OPL2 */
        return OPL->status & (OPL->statusmask|0x80);
    }

#if BUILD_Y8950
    /* data port */
    switch(OPL->address)
    {
    case 0x05: /* KeyBoard IN */
        if(OPL->type&OPL_TYPE_KEYBOARD)
        {
            if(OPL->keyboardhandler_r)
                return OPL->keyboardhandler_r(OPL->keyboard_param);
            else
                OPL->device->logerror("Y8950: read unmapped KEYBOARD port\n");
        }
        return 0;

    case 0x0f: /* ADPCM-DATA  */
        if(OPL->type&OPL_TYPE_ADPCM)
        {
            UINT8 val;

            val = YM_DELTAT_ADPCM_Read(OPL->deltat);
            /*logerror("Y8950: read ADPCM value read=%02x\n",val);*/
            return val;
        }
        return 0;

    case 0x19: /* I/O DATA    */
        if(OPL->type&OPL_TYPE_IO)
        {
            if(OPL->porthandler_r)
                return OPL->porthandler_r(OPL->port_param);
            else
                OPL->device->logerror("Y8950:read unmapped I/O port\n");
        }
        return 0;
    case 0x1a: /* PCM-DATA    */
        if(OPL->type&OPL_TYPE_ADPCM)
        {
            OPL->device->logerror("Y8950 A/D convertion is accessed but not implemented !\n");
            return 0x80; /* 2's complement PCM data - result from A/D convertion */
        }
        return 0;
    }
#endif

    return 0xff;
}

/* CSM Key Controll */
static void CSMKeyControll(OPL_CH *CH)
{
    FM_KEYON (&CH->SLOT[SLOT1], 4);
    FM_KEYON (&CH->SLOT[SLOT2], 4);

    /* The key off should happen exactly one sample later - not implemented correctly yet */

    FM_KEYOFF(&CH->SLOT[SLOT1], ~4);
    FM_KEYOFF(&CH->SLOT[SLOT2], ~4);
}


static int OPLTimerOver(FM_OPL *OPL,int c)
{
    if( c )
    {   /* Timer B */
        OPL_STATUS_SET(OPL,0x20);
    }
    else
    {   /* Timer A */
        OPL_STATUS_SET(OPL,0x40);
        /* CSM mode key,TL controll */
        if( OPL->mode & 0x80 )
        {   /* CSM mode total level latch and auto key on */
            int ch;
            if(OPL->UpdateHandler) OPL->UpdateHandler(OPL->UpdateParam,0);
            for(ch=0; ch<9; ch++)
                CSMKeyControll( &OPL->P_CH[ch] );
        }
    }
    /* reload timer */
    if (OPL->timer_handler) (OPL->timer_handler)(c,OPL->TimerBase * OPL->T[c]);
    return OPL->status>>7;
}


#define MAX_OPL_CHIPS 2


#if (BUILD_YM3812)

void * YM3812Init(device_t *device, UINT32 clock, UINT32 rate)
{
    /* emulator create */
    FM_OPL *YM3812 = OPLCreate(device,clock,rate,OPL_TYPE_YM3812);
    if (YM3812)
    {
        OPL_save_state(YM3812, device);
        YM3812ResetChip(YM3812);
    }
    return YM3812;
}

void YM3812Shutdown(void *chip)
{
    FM_OPL *YM3812 = (FM_OPL *)chip;

    /* emulator shutdown */
    OPLDestroy(YM3812);
}
void YM3812ResetChip(void *chip)
{
    FM_OPL *YM3812 = (FM_OPL *)chip;
    OPLResetChip(YM3812);
}

int YM3812Write(void *chip, int a, int v)
{
    FM_OPL *YM3812 = (FM_OPL *)chip;

    OPLWriteReg(YM3812, a, v);
    return (YM3812->status>>7);

    // technically correct, but breaks Wolf4SDL - FW19
    //return OPLWrite(YM3812, a, v);
}

unsigned char YM3812Read(void *chip, int a)
{
    FM_OPL *YM3812 = (FM_OPL *)chip;
    /* YM3812 always returns bit2 and bit1 in HIGH state */
    return OPLRead(YM3812, a) | 0x06 ;
}
int YM3812TimerOver(void *chip, int c)
{
    FM_OPL *YM3812 = (FM_OPL *)chip;
    return OPLTimerOver(YM3812, c);
}

void YM3812SetTimerHandler(void *chip, OPL_TIMERHANDLER timer_handler, void *param)
{
    FM_OPL *YM3812 = (FM_OPL *)chip;
    OPLSetTimerHandler(YM3812, timer_handler, param);
}
void YM3812SetIRQHandler(void *chip,OPL_IRQHANDLER IRQHandler,void *param)
{
    FM_OPL *YM3812 = (FM_OPL *)chip;
    OPLSetIRQHandler(YM3812, IRQHandler, param);
}
void YM3812SetUpdateHandler(void *chip,OPL_UPDATEHANDLER UpdateHandler,void *param)
{
    FM_OPL *YM3812 = (FM_OPL *)chip;
    OPLSetUpdateHandler(YM3812, UpdateHandler, param);
}


/*
** Generate samples for one of the YM3812's
**
** 'which' is the virtual YM3812 number
** '*buffer' is the output buffer pointer
** 'length' is the number of samples that should be generated
*/
void YM3812UpdateOne(void *chip, OPLSAMPLE *buffer, int length)
{
    FM_OPL      *OPL = (FM_OPL *)chip;
    UINT8       rhythm = OPL->rhythm&0x20;
    OPLSAMPLE   *buf = buffer;
    int i;

    for( i=0; i < length ; i++ )
    {
        int lt;

        OPL->output[0] = 0;

        advance_lfo(OPL);

        /* FM part */
        OPL_CALC_CH(OPL, &OPL->P_CH[0]);
        OPL_CALC_CH(OPL, &OPL->P_CH[1]);
        OPL_CALC_CH(OPL, &OPL->P_CH[2]);
        OPL_CALC_CH(OPL, &OPL->P_CH[3]);
        OPL_CALC_CH(OPL, &OPL->P_CH[4]);
        OPL_CALC_CH(OPL, &OPL->P_CH[5]);

        if(!rhythm)
        {
            OPL_CALC_CH(OPL, &OPL->P_CH[6]);
            OPL_CALC_CH(OPL, &OPL->P_CH[7]);
            OPL_CALC_CH(OPL, &OPL->P_CH[8]);
        }
        else        /* Rhythm part */
        {
            OPL_CALC_RH(OPL, &OPL->P_CH[0], (OPL->noise_rng>>0)&1 );
        }

        lt = OPL->output[0];

        //lt >>= FINAL_SH;
        lt <<= 2;

        /* limit check */
        lt = limit( lt , MAXOUT, MINOUT );

#ifdef SAVE_SAMPLE
        if (which==0)
        {
            SAVE_ALL_CHANNELS
		}
#endif

        /* store to sound buffer */
        //buf[i] = lt;

        buf[i*2] = lt;          // stereo version
        buf[i*2+1] = lt;

        advance(OPL);
    }
}
#endif /* BUILD_YM3812 */

// Rockbox: we don't care about the rest.

#if (BUILD_YM3526)

void *ym3526_init(device_t *device, UINT32 clock, UINT32 rate)
{
    /* emulator create */
    FM_OPL *YM3526 = OPLCreate(device,clock,rate,OPL_TYPE_YM3526);
    if (YM3526)
    {
        OPL_save_state(YM3526, device);
        ym3526_reset_chip(YM3526);
    }
    return YM3526;
}

void ym3526_shutdown(void *chip)
{
    FM_OPL *YM3526 = (FM_OPL *)chip;
    /* emulator shutdown */
    OPLDestroy(YM3526);
}
void ym3526_reset_chip(void *chip)
{
    FM_OPL *YM3526 = (FM_OPL *)chip;
    OPLResetChip(YM3526);
}

int ym3526_write(void *chip, int a, int v)
{
    FM_OPL *YM3526 = (FM_OPL *)chip;
    return OPLWrite(YM3526, a, v);
}

unsigned char ym3526_read(void *chip, int a)
{
    FM_OPL *YM3526 = (FM_OPL *)chip;
    /* YM3526 always returns bit2 and bit1 in HIGH state */
    return OPLRead(YM3526, a) | 0x06 ;
}
int ym3526_timer_over(void *chip, int c)
{
    FM_OPL *YM3526 = (FM_OPL *)chip;
    return OPLTimerOver(YM3526, c);
}

void ym3526_set_timer_handler(void *chip, OPL_TIMERHANDLER timer_handler, void *param)
{
    FM_OPL *YM3526 = (FM_OPL *)chip;
    OPLSetTimerHandler(YM3526, timer_handler, param);
}
void ym3526_set_irq_handler(void *chip,OPL_IRQHANDLER IRQHandler,void *param)
{
    FM_OPL *YM3526 = (FM_OPL *)chip;
    OPLSetIRQHandler(YM3526, IRQHandler, param);
}
void ym3526_set_update_handler(void *chip,OPL_UPDATEHANDLER UpdateHandler,void *param)
{
    FM_OPL *YM3526 = (FM_OPL *)chip;
    OPLSetUpdateHandler(YM3526, UpdateHandler, param);
}


/*
** Generate samples for one of the YM3526's
**
** 'which' is the virtual YM3526 number
** '*buffer' is the output buffer pointer
** 'length' is the number of samples that should be generated
*/
void ym3526_update_one(void *chip, OPLSAMPLE *buffer, int length)
{
    FM_OPL      *OPL = (FM_OPL *)chip;
    UINT8       rhythm = OPL->rhythm&0x20;
    OPLSAMPLE   *buf = buffer;
    int i;

    for( i=0; i < length ; i++ )
    {
        int lt;

        OPL->output[0] = 0;

        advance_lfo(OPL);

        /* FM part */
        OPL_CALC_CH(OPL, &OPL->P_CH[0]);
        OPL_CALC_CH(OPL, &OPL->P_CH[1]);
        OPL_CALC_CH(OPL, &OPL->P_CH[2]);
        OPL_CALC_CH(OPL, &OPL->P_CH[3]);
        OPL_CALC_CH(OPL, &OPL->P_CH[4]);
        OPL_CALC_CH(OPL, &OPL->P_CH[5]);

        if(!rhythm)
        {
            OPL_CALC_CH(OPL, &OPL->P_CH[6]);
            OPL_CALC_CH(OPL, &OPL->P_CH[7]);
            OPL_CALC_CH(OPL, &OPL->P_CH[8]);
        }
        else        /* Rhythm part */
        {
            OPL_CALC_RH(OPL, &OPL->P_CH[0], (OPL->noise_rng>>0)&1 );
        }

        lt = OPL->output[0];

        lt >>= FINAL_SH;

        /* limit check */
        lt = limit( lt , MAXOUT, MINOUT );

#ifdef SAVE_SAMPLE
        if (which==0)
        {
            SAVE_ALL_CHANNELS
		}
#endif

        /* store to sound buffer */
        buf[i] = lt;

        advance(OPL);
    }

}
#endif /* BUILD_YM3526 */




#if BUILD_Y8950

static void Y8950_deltat_status_set(void *chip, UINT8 changebits)
{
    FM_OPL *Y8950 = (FM_OPL *)chip;
    OPL_STATUS_SET(Y8950, changebits);
}
static void Y8950_deltat_status_reset(void *chip, UINT8 changebits)
{
    FM_OPL *Y8950 = (FM_OPL *)chip;
    OPL_STATUS_RESET(Y8950, changebits);
}

void *y8950_init(device_t *device, UINT32 clock, UINT32 rate)
{
    /* emulator create */
    FM_OPL *Y8950 = OPLCreate(device,clock,rate,OPL_TYPE_Y8950);
    if (Y8950)
    {
        Y8950->deltat->status_set_handler = Y8950_deltat_status_set;
        Y8950->deltat->status_reset_handler = Y8950_deltat_status_reset;
        Y8950->deltat->status_change_which_chip = Y8950;
        Y8950->deltat->status_change_EOS_bit = 0x10;        /* status flag: set bit4 on End Of Sample */
        Y8950->deltat->status_change_BRDY_bit = 0x08;   /* status flag: set bit3 on BRDY (End Of: ADPCM analysis/synthesis, memory reading/writing) */

        /*Y8950->deltat->write_time = 10.0 / clock;*/       /* a single byte write takes 10 cycles of main clock */
        /*Y8950->deltat->read_time  = 8.0 / clock;*/        /* a single byte read takes 8 cycles of main clock */
        /* reset */
        OPL_save_state(Y8950, device);
        y8950_reset_chip(Y8950);
    }

    return Y8950;
}

void y8950_shutdown(void *chip)
{
    FM_OPL *Y8950 = (FM_OPL *)chip;
    /* emulator shutdown */
    OPLDestroy(Y8950);
}
void y8950_reset_chip(void *chip)
{
    FM_OPL *Y8950 = (FM_OPL *)chip;
    OPLResetChip(Y8950);
}

int y8950_write(void *chip, int a, int v)
{
    FM_OPL *Y8950 = (FM_OPL *)chip;
    return OPLWrite(Y8950, a, v);
}

unsigned char y8950_read(void *chip, int a)
{
    FM_OPL *Y8950 = (FM_OPL *)chip;
    return OPLRead(Y8950, a);
}
int y8950_timer_over(void *chip, int c)
{
    FM_OPL *Y8950 = (FM_OPL *)chip;
    return OPLTimerOver(Y8950, c);
}

void y8950_set_timer_handler(void *chip, OPL_TIMERHANDLER timer_handler, void *param)
{
    FM_OPL *Y8950 = (FM_OPL *)chip;
    OPLSetTimerHandler(Y8950, timer_handler, param);
}
void y8950_set_irq_handler(void *chip,OPL_IRQHANDLER IRQHandler,void *param)
{
    FM_OPL *Y8950 = (FM_OPL *)chip;
    OPLSetIRQHandler(Y8950, IRQHandler, param);
}
void y8950_set_update_handler(void *chip,OPL_UPDATEHANDLER UpdateHandler,void *param)
{
    FM_OPL *Y8950 = (FM_OPL *)chip;
    OPLSetUpdateHandler(Y8950, UpdateHandler, param);
}

void y8950_set_delta_t_memory(void *chip, void * deltat_mem_ptr, int deltat_mem_size )
{
    FM_OPL      *OPL = (FM_OPL *)chip;
    OPL->deltat->memory = (UINT8 *)(deltat_mem_ptr);
    OPL->deltat->memory_size = deltat_mem_size;
}

/*
** Generate samples for one of the Y8950's
**
** 'which' is the virtual Y8950 number
** '*buffer' is the output buffer pointer
** 'length' is the number of samples that should be generated
*/
void y8950_update_one(void *chip, OPLSAMPLE *buffer, int length)
{
    int i;
    FM_OPL      *OPL = (FM_OPL *)chip;
    UINT8       rhythm  = OPL->rhythm&0x20;
    YM_DELTAT   *DELTAT = OPL->deltat;
    OPLSAMPLE   *buf    = buffer;

    for( i=0; i < length ; i++ )
    {
        int lt;

        OPL->output[0] = 0;
        OPL->output_deltat[0] = 0;

        advance_lfo(OPL);

        /* deltaT ADPCM */
        if( DELTAT->portstate&0x80 )
            YM_DELTAT_ADPCM_CALC(DELTAT);

        /* FM part */
        OPL_CALC_CH(OPL, &OPL->P_CH[0]);
        OPL_CALC_CH(OPL, &OPL->P_CH[1]);
        OPL_CALC_CH(OPL, &OPL->P_CH[2]);
        OPL_CALC_CH(OPL, &OPL->P_CH[3]);
        OPL_CALC_CH(OPL, &OPL->P_CH[4]);
        OPL_CALC_CH(OPL, &OPL->P_CH[5]);

        if(!rhythm)
        {
            OPL_CALC_CH(OPL, &OPL->P_CH[6]);
            OPL_CALC_CH(OPL, &OPL->P_CH[7]);
            OPL_CALC_CH(OPL, &OPL->P_CH[8]);
        }
        else        /* Rhythm part */
        {
            OPL_CALC_RH(OPL, &OPL->P_CH[0], (OPL->noise_rng>>0)&1 );
        }

        lt = OPL->output[0] + (OPL->output_deltat[0]>>11);

        lt >>= FINAL_SH;

        /* limit check */
        lt = limit( lt , MAXOUT, MINOUT );

#ifdef SAVE_SAMPLE
        if (which==0)
        {
            SAVE_ALL_CHANNELS
		}
#endif

        /* store to sound buffer */
        buf[i] = lt;

        advance(OPL);
    }

}

void y8950_set_port_handler(void *chip,OPL_PORTHANDLER_W PortHandler_w,OPL_PORTHANDLER_R PortHandler_r,void * param)
{
    FM_OPL      *OPL = (FM_OPL *)chip;
    OPL->porthandler_w = PortHandler_w;
    OPL->porthandler_r = PortHandler_r;
    OPL->port_param = param;
}

void y8950_set_keyboard_handler(void *chip,OPL_PORTHANDLER_W KeyboardHandler_w,OPL_PORTHANDLER_R KeyboardHandler_r,void * param)
{
    FM_OPL      *OPL = (FM_OPL *)chip;
    OPL->keyboardhandler_w = KeyboardHandler_w;
    OPL->keyboardhandler_r = KeyboardHandler_r;
    OPL->keyboard_param = param;
}

#endif
