fmopl.cc

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/* 
 * Copyright (C) 1999/2000 Tatsuyuki Satoh
 * Copyright (C) 2001/2002 The ScummVM project
 * Copyright (C) 2002 The Exult Team
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.

 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.

 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 * $Header: /cvsroot/exult/exult/audio/midi_drivers/fmopl.cc,v 1.3 2004/05/21 16:57:13 colourles Exp $
 *
 * LGPL licensed version of MAMEs fmopl (V0.37a modified) by
 * Tatsuyuki Satoh. Included from LGPL'ed AdPlug.
 */

#ifdef HAVE_CONFIG_H
#  include <config.h>
#endif

#ifdef USE_FMOPL_MIDI

#include "common_types.h"
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cstdarg>
#include <cmath>
#include <iostream>
#include "fmopl.h"

#ifndef UNDER_CE
using std::malloc;
using std::free;
#endif

#ifndef PI
#define PI 3.14159265358979323846
#endif

/* -------------------- preliminary define section --------------------- */
/* attack/decay rate time rate */
#define OPL_ARRATE     141280  /* RATE 4 =  2826.24ms @ 3.6MHz */
#define OPL_DRRATE    1956000  /* RATE 4 = 39280.64ms @ 3.6MHz */

#define FREQ_BITS 24      /* frequency turn          */

/* counter bits = 20 , octerve 7 */
#define FREQ_RATE   (1<<(FREQ_BITS-20))
#define TL_BITS    (FREQ_BITS+2)

/* final output shift , limit minimum and maximum */
#define OPL_OUTSB   (TL_BITS+3-16)    /* OPL output final shift 16bit */
#define OPL_MAXOUT (0x7fff<<OPL_OUTSB)
#define OPL_MINOUT (-0x8000<<OPL_OUTSB)

/* -------------------- quality selection --------------------- */

/* sinwave entries */
/* used static memory = SIN_ENT * 4 (byte) */
#define SIN_ENT 2048

/* output level entries (envelope,sinwave) */
/* envelope counter lower bits */
#define ENV_BITS 16
/* envelope output entries */
#define EG_ENT   4096
/* used dynamic memory = EG_ENT*4*4(byte)or EG_ENT*6*4(byte) */
/* used static  memory = EG_ENT*4 (byte)                     */

#define EG_OFF   ((2*EG_ENT)<<ENV_BITS)  /* OFF          */
#define EG_DED   EG_OFF
#define EG_DST   (EG_ENT<<ENV_BITS)      /* DECAY  START */
#define EG_AED   EG_DST
#define EG_AST   0                       /* ATTACK START */

#define EG_STEP (96.0/EG_ENT) /* OPL is 0.1875 dB step  */

/* LFO table entries */
#define VIB_ENT 512
#define VIB_SHIFT (32-9)
#define AMS_ENT 512
#define AMS_SHIFT (32-9)

#define VIB_RATE 256

/* -------------------- local defines , macros --------------------- */

/* register number to channel number , slot offset */
#define SLOT1 0
#define SLOT2 1

/* envelope phase */
#define ENV_MOD_RR  0x00
#define ENV_MOD_DR  0x01
#define ENV_MOD_AR  0x02

/* -------------------- tables --------------------- */
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
};

#define SC(mydb) ((uint32) (mydb / (EG_STEP/2)))

static const uint32 KSL_TABLE[8 * 16] = {
  /* OCT 0 */
  SC(0.000), SC(0.000), SC(0.000), SC(0.000),
  SC(0.000), SC(0.000), SC(0.000), SC(0.000),
  SC(0.000), SC(0.000), SC(0.000), SC(0.000),
  SC(0.000), SC(0.000), SC(0.000), SC(0.000),
  /* OCT 1 */
  SC(0.000), SC(0.000), SC(0.000), SC(0.000),
  SC(0.000), SC(0.000), SC(0.000), SC(0.000),
  SC(0.000), SC(0.750), SC(1.125), SC(1.500),
  SC(1.875), SC(2.250), SC(2.625), SC(3.000),
  /* OCT 2 */
  SC(0.000), SC(0.000), SC(0.000), SC(0.000),
  SC(0.000), SC(1.125), SC(1.875), SC(2.625),
  SC(3.000), SC(3.750), SC(4.125), SC(4.500),
  SC(4.875), SC(5.250), SC(5.625), SC(6.000),
  /* OCT 3 */
  SC(0.000), SC(0.000), SC(0.000), SC(1.875),
  SC(3.000), SC(4.125), SC(4.875), SC(5.625),
  SC(6.000), SC(6.750), SC(7.125), SC(7.500),
  SC(7.875), SC(8.250), SC(8.625), SC(9.000),
  /* OCT 4 */
  SC(0.000), SC(0.000), SC(3.000), SC(4.875),
  SC(6.000), SC(7.125), SC(7.875), SC(8.625),
  SC(9.000), SC(9.750), SC(10.125), SC(10.500),
  SC(10.875), SC(11.250), SC(11.625), SC(12.000),
  /* OCT 5 */
  SC(0.000), SC(3.000), SC(6.000), SC(7.875),
  SC(9.000), SC(10.125), SC(10.875), SC(11.625),
  SC(12.000), SC(12.750), SC(13.125), SC(13.500),
  SC(13.875), SC(14.250), SC(14.625), SC(15.000),
  /* OCT 6 */
  SC(0.000), SC(6.000), SC(9.000), SC(10.875),
  SC(12.000), SC(13.125), SC(13.875), SC(14.625),
  SC(15.000), SC(15.750), SC(16.125), SC(16.500),
  SC(16.875), SC(17.250), SC(17.625), SC(18.000),
  /* OCT 7 */
  SC(0.000), SC(9.000), SC(12.000), SC(13.875),
  SC(15.000), SC(16.125), SC(16.875), SC(17.625),
  SC(18.000), SC(18.750), SC(19.125), SC(19.500),
  SC(19.875), SC(20.250), SC(20.625), SC(21.000)
};
#undef SC


/* sustain lebel 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) (int)(db*((3/EG_STEP)*(1<<ENV_BITS)))+EG_DST
static const int SL_TABLE[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 TL_MAX (EG_ENT*2) /* limit(tl + ksr + envelope) + sinwave */
/* TotalLevel : 48 24 12  6  3 1.5 0.75 (dB) */
/* TL_TABLE[ 0      to TL_MAX          ] : plus  section */
/* TL_TABLE[ TL_MAX to TL_MAX+TL_MAX-1 ] : minus section */
static int *TL_TABLE;

/* pointers to TL_TABLE with sinwave output offset */
static int **SIN_TABLE;

/* LFO table */
static int *AMS_TABLE;
static int *VIB_TABLE;

/* envelope output curve table */
/* attack + decay + OFF */
static int ENV_CURVE[2*EG_ENT+1];

/* multiple table */
#define ML(a) (int)(a*2)
static const uint32 MUL_TABLE[16]= {
/* 1/2, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14,15 */
   ML(0.50), ML(1.00), ML(2.00),  ML(3.00), ML(4.00), ML(5.00), ML(6.00), ML(7.00),
   ML(8.00), ML(9.00), ML(10.00), ML(10.00),ML(12.00),ML(12.00),ML(15.00),ML(15.00)
};
#undef ML

/* dummy attack / decay rate ( when rate == 0 ) */
static int RATE_0[16]=
{0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};

/* -------------------- static state --------------------- */

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

/* work table */
static void *cur_chip = NULL; /* current chip point */
/* currenct chip state */
/* static OPLSAMPLE  *bufL,*bufR; */
static OPL_CH *S_CH;
static OPL_CH *E_CH;
OPL_SLOT *SLOT7_1,*SLOT7_2,*SLOT8_1,*SLOT8_2;

static int outd[1];
static int ams;
static int vib;
int  *ams_table;
int  *vib_table;
static int amsIncr;
static int vibIncr;
static int feedback2;   /* connect for SLOT 2 */

/* --------------------- subroutines  --------------------- */

inline 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 */
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;
      /* callback user interrupt handler (IRQ is OFF to ON) */
      if(OPL->IRQHandler) (OPL->IRQHandler)(OPL->IRQParam,1);
    }
  }
}

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

/* IRQ mask set */
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);
}

/* ----- key on  ----- */
inline void OPL_KEYON(OPL_SLOT *SLOT)
{
  /* sin wave restart */
  SLOT->Cnt = 0;
  /* set attack */
  SLOT->evm = ENV_MOD_AR;
  SLOT->evs = SLOT->evsa;
  SLOT->evc = EG_AST;
  SLOT->eve = EG_AED;
}
/* ----- key off ----- */
inline void OPL_KEYOFF(OPL_SLOT *SLOT)
{
  if( SLOT->evm > ENV_MOD_RR)
  {
    /* set envelope counter from envleope output */
    SLOT->evm = ENV_MOD_RR;
    if( !(SLOT->evc&EG_DST) )
      //SLOT->evc = (ENV_CURVE[SLOT->evc>>ENV_BITS]<<ENV_BITS) + EG_DST;
      SLOT->evc = EG_DST;
    SLOT->eve = EG_DED;
    SLOT->evs = SLOT->evsr;
  }
}

/* ---------- calcrate Envelope Generator & Phase Generator ---------- */
/* return : envelope output */
inline uint32 OPL_CALC_SLOT( OPL_SLOT *SLOT )
{
  /* calcrate envelope generator */
  if( (SLOT->evc+=SLOT->evs) >= SLOT->eve )
  {
    switch( SLOT->evm ){
    case ENV_MOD_AR: /* ATTACK -> DECAY1 */
      /* next DR */
      SLOT->evm = ENV_MOD_DR;
      SLOT->evc = EG_DST;
      SLOT->eve = SLOT->SL;
      SLOT->evs = SLOT->evsd;
      break;
    case ENV_MOD_DR: /* DECAY -> SL or RR */
      SLOT->evc = SLOT->SL;
      SLOT->eve = EG_DED;
      if(SLOT->eg_typ)
      {
        SLOT->evs = 0;
      }
      else
      {
        SLOT->evm = ENV_MOD_RR;
        SLOT->evs = SLOT->evsr;
      }
      break;
    case ENV_MOD_RR: /* RR -> OFF */
      SLOT->evc = EG_OFF;
      SLOT->eve = EG_OFF+1;
      SLOT->evs = 0;
      break;
    }
  }
  /* calcrate envelope */
  return SLOT->TLL+ENV_CURVE[SLOT->evc>>ENV_BITS]+(SLOT->ams ? ams : 0);
}

/* set algorythm connection */
static void set_algorythm( OPL_CH *CH)
{
  int *carrier = &outd[0];
  CH->connect1 = CH->CON ? carrier : &feedback2;
  CH->connect2 = carrier;
}

/* ---------- frequency counter for operater update ---------- */
inline void CALC_FCSLOT(OPL_CH *CH,OPL_SLOT *SLOT)
{
  int ksr;

  /* frequency step counter */
  SLOT->Incr = CH->fc * SLOT->mul;
  ksr = CH->kcode >> SLOT->KSR;

  if( SLOT->ksr != ksr )
  {
    SLOT->ksr = ksr;
    /* attack , decay rate recalcration */
    SLOT->evsa = SLOT->AR[ksr];
    SLOT->evsd = SLOT->DR[ksr];
    SLOT->evsr = SLOT->RR[ksr];
  }
  SLOT->TLL = SLOT->TL + (CH->ksl_base>>SLOT->ksl);
}

/* set multi,am,vib,EG-TYP,KSR,mul */
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_TABLE[v&0x0f];
  SLOT->KSR    = (v&0x10) ? 0 : 2;
  SLOT->eg_typ = (v&0x20)>>5;
  SLOT->vib    = (v&0x40);
  SLOT->ams    = (v&0x80);
  CALC_FCSLOT(CH,SLOT);
}

/* set ksl & tl */
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];
  int ksl = v>>6; /* 0 / 1.5 / 3 / 6 db/OCT */

  SLOT->ksl = ksl ? 3-ksl : 31;
  SLOT->TL  = (int)((v&0x3f)*(0.75/EG_STEP)); /* 0.75db step */

  if( !(OPL->mode&0x80) )
  { /* not CSM latch total level */
    SLOT->TLL = SLOT->TL + (CH->ksl_base>>SLOT->ksl);
  }
}

/* set attack rate & decay rate  */
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];
  int ar = v>>4;
  int dr = v&0x0f;

  SLOT->AR = ar ? &OPL->AR_TABLE[ar<<2] : RATE_0;
  SLOT->evsa = SLOT->AR[SLOT->ksr];
  if( SLOT->evm == ENV_MOD_AR ) SLOT->evs = SLOT->evsa;

  SLOT->DR = dr ? &OPL->DR_TABLE[dr<<2] : RATE_0;
  SLOT->evsd = SLOT->DR[SLOT->ksr];
  if( SLOT->evm == ENV_MOD_DR ) SLOT->evs = SLOT->evsd;
}

/* set sustain level & release rate */
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];
  int sl = v>>4;
  int rr = v & 0x0f;

  SLOT->SL = SL_TABLE[sl];
  if( SLOT->evm == ENV_MOD_DR ) SLOT->eve = SLOT->SL;
  SLOT->RR = &OPL->DR_TABLE[rr<<2];
  SLOT->evsr = SLOT->RR[SLOT->ksr];
  if( SLOT->evm == ENV_MOD_RR ) SLOT->evs = SLOT->evsr;
}

/* operator output calcrator */
#define OP_OUT(slot,env,con)   slot->wavetable[((slot->Cnt+con)/(0x1000000/SIN_ENT))&(SIN_ENT-1)][env]
/* ---------- calcrate one of channel ---------- */
inline void OPL_CALC_CH( OPL_CH *CH )
{
  uint32 env_out;
  OPL_SLOT *SLOT;

  feedback2 = 0;
  /* SLOT 1 */
  SLOT = &CH->SLOT[SLOT1];
  env_out=OPL_CALC_SLOT(SLOT);
  if( env_out < EG_ENT-1 )
  {
    /* PG */
    if(SLOT->vib) SLOT->Cnt += (SLOT->Incr*vib/VIB_RATE);
    else          SLOT->Cnt += SLOT->Incr;
    /* connectoion */
    if(CH->FB)
    {
      int feedback1 = (CH->op1_out[0]+CH->op1_out[1])>>CH->FB;
      CH->op1_out[1] = CH->op1_out[0];
      *CH->connect1 += CH->op1_out[0] = OP_OUT(SLOT,env_out,feedback1);
    }
    else
    {
      *CH->connect1 += OP_OUT(SLOT,env_out,0);
    }
  }else
  {
    CH->op1_out[1] = CH->op1_out[0];
    CH->op1_out[0] = 0;
  }
  /* SLOT 2 */
  SLOT = &CH->SLOT[SLOT2];
  env_out=OPL_CALC_SLOT(SLOT);
  if( env_out < EG_ENT-1 )
  {
    /* PG */
    if(SLOT->vib) SLOT->Cnt += (SLOT->Incr*vib/VIB_RATE);
    else          SLOT->Cnt += SLOT->Incr;
    /* connectoion */
    outd[0] += OP_OUT(SLOT,env_out, feedback2);
  }
}

/* ---------- calcrate rythm block ---------- */
#define WHITE_NOISE_db 6.0
inline void OPL_CALC_RH( OPL_CH *CH )
{
  uint32 env_tam,env_sd,env_top,env_hh;
  int whitenoise = int((std::rand()&1)*(WHITE_NOISE_db/EG_STEP));
  int tone8;

  OPL_SLOT *SLOT;
  int env_out;

  /* BD : same as FM serial mode and output level is large */
  feedback2 = 0;
  /* SLOT 1 */
  SLOT = &CH[6].SLOT[SLOT1];
  env_out=OPL_CALC_SLOT(SLOT);
  if( env_out < EG_ENT-1 )
  {
    /* PG */
    if(SLOT->vib) SLOT->Cnt += (SLOT->Incr*vib/VIB_RATE);
    else          SLOT->Cnt += SLOT->Incr;
    /* connectoion */
    if(CH[6].FB)
    {
      int feedback1 = (CH[6].op1_out[0]+CH[6].op1_out[1])>>CH[6].FB;
      CH[6].op1_out[1] = CH[6].op1_out[0];
      feedback2 = CH[6].op1_out[0] = OP_OUT(SLOT,env_out,feedback1);
    }
    else
    {
      feedback2 = OP_OUT(SLOT,env_out,0);
    }
  }else
  {
    feedback2 = 0;
    CH[6].op1_out[1] = CH[6].op1_out[0];
    CH[6].op1_out[0] = 0;
  }
  /* SLOT 2 */
  SLOT = &CH[6].SLOT[SLOT2];
  env_out=OPL_CALC_SLOT(SLOT);
  if( env_out < EG_ENT-1 )
  {
    /* PG */
    if(SLOT->vib) SLOT->Cnt += (SLOT->Incr*vib/VIB_RATE);
    else          SLOT->Cnt += SLOT->Incr;
    /* connectoion */
    outd[0] += OP_OUT(SLOT,env_out, feedback2)*2;
  }

  // SD  (17) = mul14[fnum7] + white noise
  // TAM (15) = mul15[fnum8]
  // TOP (18) = fnum6(mul18[fnum8]+whitenoise)
  // HH  (14) = fnum7(mul18[fnum8]+whitenoise) + white noise
  env_sd =OPL_CALC_SLOT(SLOT7_2) + whitenoise;
  env_tam=OPL_CALC_SLOT(SLOT8_1);
  env_top=OPL_CALC_SLOT(SLOT8_2);
  env_hh =OPL_CALC_SLOT(SLOT7_1) + whitenoise;

  /* PG */
  if(SLOT7_1->vib) SLOT7_1->Cnt += (2*SLOT7_1->Incr*vib/VIB_RATE);
  else             SLOT7_1->Cnt += 2*SLOT7_1->Incr;
  if(SLOT7_2->vib) SLOT7_2->Cnt += ((CH[7].fc*8)*vib/VIB_RATE);
  else             SLOT7_2->Cnt += (CH[7].fc*8);
  if(SLOT8_1->vib) SLOT8_1->Cnt += (SLOT8_1->Incr*vib/VIB_RATE);
  else             SLOT8_1->Cnt += SLOT8_1->Incr;
  if(SLOT8_2->vib) SLOT8_2->Cnt += ((CH[8].fc*48)*vib/VIB_RATE);
  else             SLOT8_2->Cnt += (CH[8].fc*48);

  tone8 = OP_OUT(SLOT8_2,whitenoise,0 );

  /* SD */
  if( env_sd < EG_ENT-1 )
    outd[0] += OP_OUT(SLOT7_1,env_sd, 0)*8;
  /* TAM */
  if( env_tam < EG_ENT-1 )
    outd[0] += OP_OUT(SLOT8_1,env_tam, 0)*2;
  /* TOP-CY */
  if( env_top < EG_ENT-1 )
    outd[0] += OP_OUT(SLOT7_2,env_top,tone8)*2;
  /* HH */
  if( env_hh  < EG_ENT-1 )
    outd[0] += OP_OUT(SLOT7_2,env_hh,tone8)*2;
}

/* ----------- initialize time tabls ----------- */
static void init_timetables( FM_OPL *OPL , int ARRATE , int DRRATE )
{
  int i;
  double rate;

  /* make attack rate & decay rate tables */
  for (i = 0;i < 4;i++) OPL->AR_TABLE[i] = OPL->DR_TABLE[i] = 0;
  for (i = 4;i <= 60;i++){
    rate  = OPL->freqbase;            /* frequency rate */
    if( i < 60 ) rate *= 1.0+(i&3)*0.25;    /* b0-1 : x1 , x1.25 , x1.5 , x1.75 */
    rate *= 1<<((i>>2)-1);            /* b2-5 : shift bit */
    rate *= (double)(EG_ENT<<ENV_BITS);
    OPL->AR_TABLE[i] = (int)(rate / ARRATE);
    OPL->DR_TABLE[i] = (int)(rate / DRRATE);
  }
  for (i = 60;i < 76;i++)
  {
    OPL->AR_TABLE[i] = EG_AED-1;
    OPL->DR_TABLE[i] = OPL->DR_TABLE[60];
  }
}

/* ---------- generic table initialize ---------- */
static int OPLOpenTable( void )
{
  int s,t;
  double rate;
  int i,j;
  double pom;

  /* allocate dynamic tables */
  if( (TL_TABLE = (int *)malloc(TL_MAX*2*sizeof(int))) == NULL)
    return 0;
  if( (SIN_TABLE = (int **)malloc(SIN_ENT*4 *sizeof(int *))) == NULL)
  {
    free(TL_TABLE);
    return 0;
  }
  if( (AMS_TABLE = (int *)malloc(AMS_ENT*2 *sizeof(int))) == NULL)
  {
    free(TL_TABLE);
    free(SIN_TABLE);
    return 0;
  }
  if( (VIB_TABLE = (int *)malloc(VIB_ENT*2 *sizeof(int))) == NULL)
  {
    free(TL_TABLE);
    free(SIN_TABLE);
    free(AMS_TABLE);
    return 0;
  }
  /* make total level table */
  for (t = 0;t < EG_ENT-1 ;t++){
    rate = ((1<<TL_BITS)-1)/std::pow(10,EG_STEP*t/20);  /* dB -> voltage */
    TL_TABLE[       t] =  (int)rate;
    TL_TABLE[TL_MAX+t] = -TL_TABLE[t];
  }
  /* fill volume off area */
  for ( t = EG_ENT-1; t < TL_MAX ;t++){
    TL_TABLE[t] = TL_TABLE[TL_MAX+t] = 0;
  }

  /* make sinwave table (total level offet) */
  /* degree 0 = degree 180                   = off */
  SIN_TABLE[0] = SIN_TABLE[SIN_ENT/2]         = &TL_TABLE[EG_ENT-1];
  for (s = 1;s <= SIN_ENT/4;s++){
    pom = std::sin(2*PI*s/SIN_ENT); /* sin     */
    pom = 20*std::log10(1/pom);    /* decibel */
    j = int(pom / EG_STEP);         /* TL_TABLE steps */

        /* degree 0   -  90    , degree 180 -  90 : plus section */
    SIN_TABLE[          s] = SIN_TABLE[SIN_ENT/2-s] = &TL_TABLE[j];
        /* degree 180 - 270    , degree 360 - 270 : minus section */
    SIN_TABLE[SIN_ENT/2+s] = SIN_TABLE[SIN_ENT  -s] = &TL_TABLE[TL_MAX+j];
  }
  for (s = 0;s < SIN_ENT;s++)
  {
    SIN_TABLE[SIN_ENT*1+s] = s<(SIN_ENT/2) ? SIN_TABLE[s] : &TL_TABLE[EG_ENT];
    SIN_TABLE[SIN_ENT*2+s] = SIN_TABLE[s % (SIN_ENT/2)];
    SIN_TABLE[SIN_ENT*3+s] = (s/(SIN_ENT/4))&1 ? &TL_TABLE[EG_ENT] : SIN_TABLE[SIN_ENT*2+s];
  }

  /* envelope counter -> envelope output table */
  for (i=0; i<EG_ENT; i++)
  {
    /* ATTACK curve */
    pom = std::pow( ((double)(EG_ENT-1-i)/EG_ENT) , 8 ) * EG_ENT;
    /* if( pom >= EG_ENT ) pom = EG_ENT-1; */
    ENV_CURVE[i] = (int)pom;
    /* DECAY ,RELEASE curve */
    ENV_CURVE[(EG_DST>>ENV_BITS)+i]= i;
  }
  /* off */
  ENV_CURVE[EG_OFF>>ENV_BITS]= EG_ENT-1;
  /* make LFO ams table */
  for (i=0; i<AMS_ENT; i++)
  {
    pom = (1.0+std::sin(2*PI*i/AMS_ENT))/2; /* sin */
    AMS_TABLE[i]         = (int)((1.0/EG_STEP)*pom); /* 1dB   */
    AMS_TABLE[AMS_ENT+i] = (int)((4.8/EG_STEP)*pom); /* 4.8dB */
  }
  /* make LFO vibrate table */
  for (i=0; i<VIB_ENT; i++)
  {
    /* 100cent = 1seminote = 6% ?? */
    pom = (double)VIB_RATE*0.06*std::sin(2*PI*i/VIB_ENT); /* +-100sect step */
    VIB_TABLE[i]         = (int)(VIB_RATE + (pom*0.07)); /* +- 7cent */
    VIB_TABLE[VIB_ENT+i] = (int)(VIB_RATE + (pom*0.14)); /* +-14cent */
  }
  return 1;
}


static void OPLCloseTable( void )
{
  free(TL_TABLE);
  free(SIN_TABLE);
  free(AMS_TABLE);
  free(VIB_TABLE);
}

/* CSM Key Controll */
inline void CSMKeyControll(OPL_CH *CH)
{
  OPL_SLOT *slot1 = &CH->SLOT[SLOT1];
  OPL_SLOT *slot2 = &CH->SLOT[SLOT2];
  /* all key off */
  OPL_KEYOFF(slot1);
  OPL_KEYOFF(slot2);
  /* total level latch */
  slot1->TLL = slot1->TL + (CH->ksl_base>>slot1->ksl);
  slot1->TLL = slot1->TL + (CH->ksl_base>>slot1->ksl);
  /* key on */
  CH->op1_out[0] = CH->op1_out[1] = 0;
  OPL_KEYON(slot1);
  OPL_KEYON(slot2);
}

/* ---------- opl initialize ---------- */
static void OPL_initalize(FM_OPL *OPL)
{
  int fn;

  /* frequency base */
  OPL->freqbase = (OPL->rate) ? ((double)OPL->clock / OPL->rate) / 72  : 0;
  /* Timer base time */
  OPL->TimerBase = 1.0/((double)OPL->clock / 72.0 );
  /* make time tables */
  init_timetables( OPL , OPL_ARRATE , OPL_DRRATE );
  /* make fnumber -> increment counter table */
  for( fn=0 ; fn < 1024 ; fn++ )
  {
    OPL->FN_TABLE[fn] = (uint32)(OPL->freqbase * fn * FREQ_RATE * (1<<7) / 2);
  }
  /* LFO freq.table */
  OPL->amsIncr = (int)(OPL->rate ? (double)AMS_ENT*(1<<AMS_SHIFT) / OPL->rate * 3.7 * ((double)OPL->clock/3600000) : 0);
  OPL->vibIncr = (int)(OPL->rate ? (double)VIB_ENT*(1<<VIB_SHIFT) / OPL->rate * 6.4 * ((double)OPL->clock/3600000) : 0);
}

/* ---------- write a OPL registers ---------- */
void OPLWriteReg(FM_OPL *OPL, int r, int v)
{
  OPL_CH *CH;
  int slot;
  uint32 block_fnum;

  switch(r&0xe0)
  {
  case 0x00: /* 00-1f:controll */
    switch(r&0x1f)
    {
    case 0x01:
      /* wave selector enable */
      if(OPL->type&OPL_TYPE_WAVESEL)
      {
        OPL->wavesel = v&0x20;
        if(!OPL->wavesel)
        {
          /* preset compatible mode */
          int c;
          for(c=0;c<OPL->max_ch;c++)
          {
            OPL->P_CH[c].SLOT[SLOT1].wavetable = &SIN_TABLE[0];
            OPL->P_CH[c].SLOT[SLOT2].wavetable = &SIN_TABLE[0];
          }
        }
      }
      return;
    case 0x02:  /* Timer 1 */
      OPL->T[0] = (256-v)*4;
      break;
    case 0x03:  /* Timer 2 */
      OPL->T[1] = (256-v)*16;
      return;
    case 0x04:  /* IRQ clear / mask and Timer enable */
      if(v&0x80)
      { /* IRQ flag clear */
        OPL_STATUS_RESET(OPL,0x7f);
      }
      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);
        OPL_STATUSMASK_SET(OPL,((~v)&0x78)|0x01);
        /* timer 2 */
        if(OPL->st[1] != st2)
        {
          double interval = st2 ? (double)OPL->T[1]*OPL->TimerBase : 0.0;
          OPL->st[1] = st2;
          if (OPL->TimerHandler) (OPL->TimerHandler)(OPL->TimerParam+1,interval);
        }
        /* timer 1 */
        if(OPL->st[0] != st1)
        {
          double interval = st1 ? (double)OPL->T[0]*OPL->TimerBase : 0.0;
          OPL->st[0] = st1;
          if (OPL->TimerHandler) (OPL->TimerHandler)(OPL->TimerParam+0,interval);
        }
      }
      return;
    }
    break;
  case 0x20:  /* am,vib,ksr,eg type,mul */
    slot = slot_array[r&0x1f];
    if(slot == -1) return;
    set_mul(OPL,slot,v);
    return;
  case 0x40:
    slot = slot_array[r&0x1f];
    if(slot == -1) return;
    set_ksl_tl(OPL,slot,v);
    return;
  case 0x60:
    slot = slot_array[r&0x1f];
    if(slot == -1) return;
    set_ar_dr(OPL,slot,v);
    return;
  case 0x80:
    slot = slot_array[r&0x1f];
    if(slot == -1) return;
    set_sl_rr(OPL,slot,v);
    return;
  case 0xa0:
    switch(r)
    {
    case 0xbd:
      /* amsep,vibdep,r,bd,sd,tom,tc,hh */
      {
      uint8 rkey = OPL->rythm^v;
      OPL->ams_table = &AMS_TABLE[v&0x80 ? AMS_ENT : 0];
      OPL->vib_table = &VIB_TABLE[v&0x40 ? VIB_ENT : 0];
      OPL->rythm  = v&0x3f;
      if(OPL->rythm&0x20)
      {
        /* BD key on/off */
        if(rkey&0x10)
        {
          if(v&0x10)
          {
            OPL->P_CH[6].op1_out[0] = OPL->P_CH[6].op1_out[1] = 0;
            OPL_KEYON(&OPL->P_CH[6].SLOT[SLOT1]);
            OPL_KEYON(&OPL->P_CH[6].SLOT[SLOT2]);
          }
          else
          {
            OPL_KEYOFF(&OPL->P_CH[6].SLOT[SLOT1]);
            OPL_KEYOFF(&OPL->P_CH[6].SLOT[SLOT2]);
          }
        }
        /* SD key on/off */
        if(rkey&0x08)
        {
          if(v&0x08) OPL_KEYON(&OPL->P_CH[7].SLOT[SLOT2]);
          else       OPL_KEYOFF(&OPL->P_CH[7].SLOT[SLOT2]);
        }/* TAM key on/off */
        if(rkey&0x04)
        {
          if(v&0x04) OPL_KEYON(&OPL->P_CH[8].SLOT[SLOT1]);
          else       OPL_KEYOFF(&OPL->P_CH[8].SLOT[SLOT1]);
        }
        /* TOP-CY key on/off */
        if(rkey&0x02)
        {
          if(v&0x02) OPL_KEYON(&OPL->P_CH[8].SLOT[SLOT2]);
          else       OPL_KEYOFF(&OPL->P_CH[8].SLOT[SLOT2]);
        }
        /* HH key on/off */
        if(rkey&0x01)
        {
          if(v&0x01) OPL_KEYON(&OPL->P_CH[7].SLOT[SLOT1]);
          else       OPL_KEYOFF(&OPL->P_CH[7].SLOT[SLOT1]);
        }
      }
      }
      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 */
      int keyon = (v>>5)&1;
      block_fnum = ((v&0x1f)<<8) | (CH->block_fnum&0xff);
      if(CH->keyon != keyon)
      {
        if( (CH->keyon=keyon) )
        {
          CH->op1_out[0] = CH->op1_out[1] = 0;
          OPL_KEYON(&CH->SLOT[SLOT1]);
          OPL_KEYON(&CH->SLOT[SLOT2]);
        }
        else
        {
          OPL_KEYOFF(&CH->SLOT[SLOT1]);
          OPL_KEYOFF(&CH->SLOT[SLOT2]);
        }
      }
    }
    /* update */
    if(CH->block_fnum != block_fnum)
    {
      int blockRv = 7-(block_fnum>>10);
      int fnum   = block_fnum&0x3ff;
      CH->block_fnum = block_fnum;

      CH->ksl_base = KSL_TABLE[block_fnum>>6];
      CH->fc = OPL->FN_TABLE[fnum]>>blockRv;
      CH->kcode = CH->block_fnum>>9;
      if( (OPL->mode&0x40) && CH->block_fnum&0x100) CH->kcode |=1;
      CALC_FCSLOT(CH,&CH->SLOT[SLOT1]);
      CALC_FCSLOT(CH,&CH->SLOT[SLOT2]);
    }
    return;
  case 0xc0:
    /* FB,C */
    if( (r&0x0f) > 8) return;
    CH = &OPL->P_CH[r&0x0f];
    {
    int feedback = (v>>1)&7;
    CH->FB   = feedback ? (8+1) - feedback : 0;
    CH->CON = v&1;
    set_algorythm(CH);
    }
    return;
  case 0xe0: /* wave type */
    slot = slot_array[r&0x1f];
    if(slot == -1) return;
    CH = &OPL->P_CH[slot/2];
    if(OPL->wavesel)
    {
      CH->SLOT[slot&1].wavetable = &SIN_TABLE[(v&0x03)*SIN_ENT];
    }
    return;
  }
}

/* lock/unlock for common table */
static int OPL_LockTable(void)
{
  num_lock++;
  if(num_lock>1) return 0;
  /* first time */
  cur_chip = NULL;
  /* allocate total level table (128kb space) */
  if( !OPLOpenTable() )
  {
    num_lock--;
    return -1;
  }
  return 0;
}

static void OPL_UnLockTable(void)
{
  if(num_lock) num_lock--;
  if(num_lock) return;
  /* last time */
  cur_chip = NULL;
  OPLCloseTable();
}

/*******************************************************************************/
/*    YM3812 local section                                                   */
/*******************************************************************************/

/* ---------- update one of chip ----------- */
void YM3812UpdateOne(FM_OPL *OPL, sint16 *buffer, int length)
{
    int i;
  int data;
  sint16 *buf = buffer;
  uint32 amsCnt  = OPL->amsCnt;
  uint32 vibCnt  = OPL->vibCnt;
  uint8 rythm = OPL->rythm&0x20;
  OPL_CH *CH,*R_CH;

  if( (void *)OPL != cur_chip ){
    cur_chip = (void *)OPL;
    /* channel pointers */
    S_CH = OPL->P_CH;
    E_CH = &S_CH[9];
    /* rythm slot */
    SLOT7_1 = &S_CH[7].SLOT[SLOT1];
    SLOT7_2 = &S_CH[7].SLOT[SLOT2];
    SLOT8_1 = &S_CH[8].SLOT[SLOT1];
    SLOT8_2 = &S_CH[8].SLOT[SLOT2];
    /* LFO state */
    amsIncr = OPL->amsIncr;
    vibIncr = OPL->vibIncr;
    ams_table = OPL->ams_table;
    vib_table = OPL->vib_table;
  }
  R_CH = rythm ? &S_CH[6] : E_CH;
    for( i=0; i < length ; i++ )
  {
    /*            channel A         channel B         channel C      */
    /* LFO */
    ams = ams_table[(amsCnt+=amsIncr)>>AMS_SHIFT];
    vib = vib_table[(vibCnt+=vibIncr)>>VIB_SHIFT];
    outd[0] = 0;
    /* FM part */
    for(CH=S_CH ; CH < R_CH ; CH++)
      OPL_CALC_CH(CH);
    /* Rythn part */
    if(rythm)
      OPL_CALC_RH(S_CH);
    /* limit check */
    data = Limit( outd[0] , OPL_MAXOUT, OPL_MINOUT );
    /* store to sound buffer */
    buf[i] = data >> OPL_OUTSB;
  }

  OPL->amsCnt = amsCnt;
  OPL->vibCnt = vibCnt;
}

/* ---------- reset a chip ---------- */
void OPLResetChip(FM_OPL *OPL)
{
  int c,s;
  int i;

  /* reset chip */
  OPL->mode   = 0;  /* normal mode */
  OPL_STATUS_RESET(OPL,0x7f);
  /* reset with register write */
  OPLWriteReg(OPL,0x01,0); /* wabesel 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 paramater */
  for( c = 0 ; c < OPL->max_ch ; c++ )
  {
    OPL_CH *CH = &OPL->P_CH[c];
    /* OPL->P_CH[c].PAN = OPN_CENTER; */
    for(s = 0 ; s < 2 ; s++ )
    {
      /* wave table */
      CH->SLOT[s].wavetable = &SIN_TABLE[0];
      /* CH->SLOT[s].evm = ENV_MOD_RR; */
      CH->SLOT[s].evc = EG_OFF;
      CH->SLOT[s].eve = EG_OFF+1;
      CH->SLOT[s].evs = 0;
    }
  }
}

/* ----------  Create a virtual YM3812 ----------       */
/* 'rate'  is sampling rate and 'bufsiz' is the size of the  */
FM_OPL *OPLCreate(int type, int clock, int rate)
{
  char *ptr;
  FM_OPL *OPL;
  int state_size;
  int max_ch = 9; /* normaly 9 channels */

  if( OPL_LockTable() ==-1) return NULL;
  /* allocate OPL state space */
  state_size  = sizeof(FM_OPL);
  state_size += sizeof(OPL_CH)*max_ch;

  /* allocate memory block */
  ptr = (char *)malloc(state_size);
  if(ptr==NULL) return NULL;

  /* clear */
  memset(ptr,0,state_size);
  OPL        = (FM_OPL *)ptr; ptr+=sizeof(FM_OPL);
  OPL->P_CH  = (OPL_CH *)ptr; ptr+=sizeof(OPL_CH)*max_ch;

  /* set channel state pointer */
  OPL->type  = type;
  OPL->clock = clock;
  OPL->rate  = rate;
  OPL->max_ch = max_ch;

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

  /* reset chip */
  OPLResetChip(OPL);
  return OPL;
}

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

/* ----------  Option handlers ----------       */

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

/* ---------- YM3812 I/O interface ---------- */
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;
}

unsigned char OPLRead(FM_OPL *OPL,int a)
{
  if( !(a&1) )
  { /* status port */
    return OPL->status & (OPL->statusmask|0x80);
  }
  /* data port */
  switch(OPL->address)
  {
  case 0x05: /* KeyBoard IN */
    CERR(("OPL:read unmapped KEYBOARD port\n"));
    return 0;
  case 0x19: /* I/O DATA    */
    CERR(("OPL:read unmapped I/O port\n"));
    return 0;
  case 0x1a: /* PCM-DATA    */
    return 0;
  }
  return 0;
}

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->TimerHandler) (OPL->TimerHandler)(OPL->TimerParam+c,(double)OPL->T[c]*OPL->TimerBase);
  return OPL->status>>7;
}

#endif //USE_FMOPL_MIDI

---