emu8950.c

/****************************************************************************

  emu8950.c -- Y8950 emulator : written by Mitsutaka Okazaki 2001

  2001 05-19 : Version 0.10 -- Test release (No rythm, No pcm).

  References: 
    fmopl.c        -- 1999,2000 written by Tatsuyuki Satoh.
    s_opl.c        -- 2001 written by Mamiya.
    fmgen.cpp      -- 1999,2000 written by cisc.
    MSX-Datapack
    YMU757 data sheet
    YM2143 data sheet

*****************************************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include "emu8950.h"

#if defined(_MSC_VER)
#define INLINE __forceinline
#elif defined(__GNUC__)
#define INLINE __inline__
#else
#define INLINE
#endif

/* Size of Sintable ( 1 -- 18 can be used, but 7 -- 14 recommended.)*/
#define PG_BITS 10
#define PG_WIDTH (1<<PG_BITS)

/* Phase increment counter */
#define DP_BITS 19
#define DP_WIDTH (1<<DP_BITS)
#define DP_BASE_BITS (DP_BITS - PG_BITS)

#define ALIGN(d,SS,SD) (d*(e_int32)(SS/SD))
#define ALIGN2(d,SS,SD) (d*(e_int32)(SS/SD))

/* Dynamic range */
#define DB_STEP 0.1875
#define DB_BITS 9
#define DB_MUTE (1<<DB_BITS)

/* Dynamic range of envelope */
#define EG_STEP 0.1875
#define EG_BITS 9
#define EG_MUTE (1<<EB_BITS)

/* Dynamic range of total level */
#define TL_STEP 0.75
#define TL_BITS 6
#define TL_MUTE (1<<TL_BITS)

/* Dynamic range of sustine level */
#define SL_STEP 3.0
#define SL_BITS 4
#define SL_MUTE (1<<SL_BITS)

/* Bits for liner value */
#define DB2LIN_AMP_BITS 11
#define SLOT_AMP_BITS (DB2LIN_AMP_BITS)

/* Bits for envelope phase incremental counter */  
#define EG_DP_BITS 23
#define EG_DP_WIDTH (1<<EG_DP_BITS)

/* Bits for Pitch and Amp modulator */
#define PM_PG_BITS 8
#define PM_PG_WIDTH (1<<PM_PG_BITS)
#define PM_DP_BITS 16
#define PM_DP_WIDTH (1<<PM_DP_BITS)
#define AM_PG_BITS 8
#define AM_PG_WIDTH (1<<AM_PG_BITS)
#define AM_DP_BITS 16
#define AM_DP_WIDTH (1<<AM_DP_BITS)

/* PM table is calcurated by PM_AMP * pow(2,PM_DEPTH*sin(x)/1200) */
#define PM_AMP_BITS 8
#define PM_AMP (1<<PM_AMP_BITS)

/* PM speed(Hz) and depth(cent) */
#define PM_SPEED 6.4
#define PM_DEPTH (13.75/2)
#define PM_DEPTH2 13.75

/* AM speed(Hz) and depth(dB) */
#define AM_SPEED 3.7
#define AM_DEPTH 1.0
#define AM_DEPTH2 4.8

/* Cut the lower b bit(s) off. */
#define HIGHBITS(c,b) ((c)>>(b))

/* Leave the lower b bit(s). */
#define LOWBITS(c,b) ((c)&((1<<(b))-1))

/* Expand x which is s bits to d bits. */
#define EXPAND_BITS(x,s,d) ((x)<<((d)-(s)))

/* Expand x which is s bits to d bits and fill expanded bits '1' */
#define EXPAND_BITS_X(x,s,d) (((x)<<((d)-(s)))|((1<<((d)-(s)))-1))

/* Adjust envelope speed which depends on sampling rate. */
#define rate_adjust(x) (e_uint32)((double)(x)*clk/72/rate + 0.5) /* +0.5 to round */

#define MOD(x) ch[x]->mod
#define CAR(x) ch[x]->car

#define SLOT_BD1 12
#define SLOT_BD2 13
#define SLOT_HH 14
#define SLOT_SD 15
#define SLOT_TOM 16
#define SLOT_CYM 17

/* Sampling rate */
static e_uint32 rate ;
/* Input clock */
static e_uint32 clk ;

/* WaveTable for each envelope amp */
static e_uint32 fullsintable[PG_WIDTH] ;

/* LFO Table */
static e_int32 pmtable[2][PM_PG_WIDTH] ;
static e_int32 amtable[2][AM_PG_WIDTH] ;

static e_uint32 pm_dphase ;
static e_int32 lfo_pm ;
static e_uint32 am_dphase ;
static e_int32 lfo_am ;
static e_uint32 whitenoise;

/* dB to Liner table */
static e_int32 DB2LIN_TABLE[(DB_MUTE + DB_MUTE)*2] ;

/* Liner to Log curve conversion table (for Attack rate). */
static e_uint32 AR_ADJUST_TABLE[1<<EG_BITS] ;

/* Definition of envelope mode */
enum { SETTLE,ATTACK,DECAY,SUSHOLD,SUSTINE,RELEASE,FINISH } ;

/* Phase incr table for Attack */
static e_uint32 dphaseARTable[16][16] ;
/* Phase incr table for Decay and Release */
static e_uint32 dphaseDRTable[16][16] ;

/* KSL + TL Table */
static e_uint32 tllTable[16][8][1<<TL_BITS][4] ;
static e_int32 rksTable[2][8][2] ;

/* Phase incr table for PG */
static e_uint32 dphaseTable[1024][8][16] ; 

/***************************************************
 
                  Create tables
 
****************************************************/
INLINE static e_int32 Min(e_int32 i,e_int32 j)
{
  if(i<j) return i ; else return j ;
}

/* Table for AR to LogCurve. */
static void makeAdjustTable(void)
{
  e_int32 i ;

  AR_ADJUST_TABLE[0] = (1<<EG_BITS);
  for ( i=1 ; i < 1<<EG_BITS ; i++)
    AR_ADJUST_TABLE[i] = (e_uint32)((double)(1<<EG_BITS)-1-(1<<EG_BITS)*log(i)/log(1<<EG_BITS)) >> 1 ; 
}

/* Table for dB(0 -- (1<<DB_BITS)) to Liner(0 -- DB2LIN_AMP_WIDTH) */
static void makeDB2LinTable(void)
{
  e_int32 i ;

  for( i=0 ; i < DB_MUTE + DB_MUTE ; i++){
    DB2LIN_TABLE[i] = (e_int32)((double)((1<<DB2LIN_AMP_BITS)-1) * pow(10,-(double)i*DB_STEP/20)) ;
    if(i>=DB_MUTE) DB2LIN_TABLE[i] = 0 ;
    DB2LIN_TABLE[i+ DB_MUTE + DB_MUTE] = -DB2LIN_TABLE[i] ;
  }
}

/* Liner(+0.0 - +1.0) to dB((1<<DB_BITS) - 1 -- 0) */
static e_int32 lin2db(double d)
{
  if(d == 0) return (DB_MUTE-1) ;
  else return Min(-(e_int32)(20.0*log10(d)/DB_STEP), DB_MUTE-1) ; /* 0 -- 128 */
}

/* Sin Table */
static void makeSinTable(void)
{
  e_int32 i ;

  for( i = 0 ; i < PG_WIDTH/4 ; i++ )
    fullsintable[i] = lin2db(sin(2.0*PI*i/PG_WIDTH)) ;

  for( i = 0 ; i < PG_WIDTH/4 ; i++ )
    fullsintable[PG_WIDTH/2 - 1 - i] = fullsintable[i] ;

  for( i = 0 ; i < PG_WIDTH/2 ; i++ )
    fullsintable[PG_WIDTH/2+i] = DB_MUTE + DB_MUTE + fullsintable[i] ;
}

/* Table for Pitch Modulator */
static void makePmTable(void)
{
  e_int32 i ;

  for(i = 0 ; i < PM_PG_WIDTH ; i++ )
    pmtable[0][i] = (e_int32)((double)PM_AMP * pow(2,(double)PM_DEPTH*sin(2.0*PI*i/PM_PG_WIDTH)/1200)) ;

  for(i = 0 ; i < PM_PG_WIDTH ; i++ )
    pmtable[1][i] = (e_int32)((double)PM_AMP * pow(2,(double)PM_DEPTH2*sin(2.0*PI*i/PM_PG_WIDTH)/1200)) ;
}

/* Table for Amp Modulator */
static void makeAmTable(void)
{
  e_int32 i ;

  for(i = 0 ; i < AM_PG_WIDTH ; i++ )
    amtable[0][i] = (e_int32)((double)AM_DEPTH/2/DB_STEP * (1.0 + sin(2.0*PI*i/PM_PG_WIDTH))) ;

  for(i = 0 ; i < AM_PG_WIDTH ; i++ )
    amtable[1][i] = (e_int32)((double)AM_DEPTH2/2/DB_STEP * (1.0 + sin(2.0*PI*i/PM_PG_WIDTH))) ;
}

/* Phase increment counter table */ 
static void makeDphaseTable(void)
{
  e_uint32 fnum, block , ML ;
  e_uint32 mltable[16]={ 1,1*2,2*2,3*2,4*2,5*2,6*2,7*2,8*2,9*2,10*2,10*2,12*2,12*2,15*2,15*2 } ;

  for(fnum=0; fnum<1024; fnum++)
    for(block=0; block<8; block++)
      for(ML=0; ML<16; ML++)
        dphaseTable[fnum][block][ML] = 
          rate_adjust((((fnum * mltable[ML]) << block ) >> (21 - DP_BITS))) ;
}

static void makeTllTable(void)
{
#define dB2(x) (e_uint32)((x)*2)

	static e_uint32 kltable[16] = {
    dB2( 0.000),dB2( 9.000),dB2(12.000),dB2(13.875),dB2(15.000),dB2(16.125),dB2(16.875),dB2(17.625),
    dB2(18.000),dB2(18.750),dB2(19.125),dB2(19.500),dB2(19.875),dB2(20.250),dB2(20.625),dB2(21.000)
	} ;
  
  e_int32 tmp ;
  e_int32 fnum, block ,TL , KL ;

  for(fnum=0; fnum<16; fnum++)
    for(block=0; block<8; block++)
      for(TL=0; TL<64; TL++)
        for(KL=0; KL<4; KL++)
        {
          if(KL==0)
          {
            tllTable[fnum][block][TL][KL] = ALIGN(TL,TL_STEP,EG_STEP) ;
          }
          else
          {
  	        tmp = kltable[fnum] - dB2(3.000) * (7 - block) ;
            if(tmp <= 0)
              tllTable[fnum][block][TL][KL] = ALIGN(TL,TL_STEP,EG_STEP) ;
            else 
              tllTable[fnum][block][TL][KL] = (e_uint32)((tmp>>(3-KL))/EG_STEP) 
                + ALIGN(TL,TL_STEP,EG_STEP) ;
          }

       }
}



/* Rate Table for Attack */
static void makeDphaseARTable(void)
{
  e_int32 AR,Rks,RM,RL ;

  for(AR=0; AR<16; AR++)
    for(Rks=0; Rks<16; Rks++){
      RM = AR + (Rks>>2) ;
      if(RM>15) RM = 15 ;
      RL = Rks&3 ;
      switch(AR){ 
       case 0:
        dphaseARTable[AR][Rks] = 0 ;
        break ;
      case 15:
        dphaseARTable[AR][Rks] = EG_DP_WIDTH ;
        break ;
      default:
        dphaseARTable[AR][Rks] = rate_adjust(( 3 * (RL + 4) << (RM + 1))) ;
        break ;
      }

    }
}

/* Rate Table for Decay */
static void makeDphaseDRTable(void)
{
  e_int32 DR,Rks,RM,RL ;

  for(DR=0; DR<16; DR++)
    for(Rks=0; Rks<16; Rks++){
      RM = DR + (Rks>>2) ;
      RL = Rks&3 ;
      if(RM>15) RM = 15 ;
      switch(DR){ 
      case 0:
        dphaseDRTable[DR][Rks] = 0 ;
        break ;
      default:
        dphaseDRTable[DR][Rks] = rate_adjust((RL + 4) << (RM - 1));
        break ;
      }

    }
}

static void makeRksTable(void)
{
  e_int32 fnum9, block, KR ;

  for(fnum9 = 0 ; fnum9 < 2 ; fnum9++)
    for(block = 0 ; block < 8 ; block++)
      for(KR = 0; KR < 2 ; KR++){
        if(KR!=0)
          rksTable[fnum9][block][KR] = ( block << 1 ) + fnum9 ;
        else
          rksTable[fnum9][block][KR] = block >> 1 ;
      }
}

/************************************************************

                      Calc Parameters

************************************************************/

INLINE static e_uint32 calc_eg_dphase(OPL_SLOT *slot)
{
  switch(slot->eg_mode)
  {
    case ATTACK:
      return dphaseARTable[slot->patch->AR][slot->rks] ;
  
    case DECAY:
      return dphaseDRTable[slot->patch->DR][slot->rks] ;
  
    case SUSHOLD:
      return 0 ;

    case SUSTINE:
      return dphaseDRTable[slot->patch->RR][slot->rks] ;
  
    case RELEASE:
      if(slot->patch->EG)
        return dphaseDRTable[slot->patch->RR][slot->rks] ;
      else 
        return dphaseDRTable[7][slot->rks] ;

    case FINISH:
      return 0 ;

    default:
      return 0 ;
  }
}

/*************************************************************

                    opl internal interfaces

*************************************************************/
#define SLOT_BD1 12
#define SLOT_BD2 13
#define SLOT_HH 14
#define SLOT_SD 15
#define SLOT_TOM 16
#define SLOT_CYM 17

#define UPDATE_PG(S)  (S)->dphase = dphaseTable[(S)->fnum][(S)->block][(S)->patch->ML]
#define UPDATE_TLL(S) \
  ((S)->tll = tllTable[((S)->fnum)>>6][(S)->block][(S)->patch->TL][(S)->patch->KL])

#define UPDATE_RKS(S) (S)->rks = rksTable[((S)->fnum)>>9][(S)->block][(S)->patch->KR] 
#define UPDATE_EG(S)  (S)->eg_dphase = calc_eg_dphase(S) 
#define UPDATE_ALL(S) \
  UPDATE_PG(S) ;\
  UPDATE_TLL(S) ;\
  UPDATE_RKS(S) ;\
  UPDATE_EG(S) /* EG should be last */

/* Slot key on  */
INLINE static void slotOn(OPL_SLOT *slot)
{
  slot->eg_mode = ATTACK ;
  slot->phase = 0 ;
  slot->eg_phase = 0 ;
}

/* Slot key off */
INLINE static void slotOff(OPL_SLOT *slot)
{
  if(slot->eg_mode == ATTACK)
    slot->eg_phase = 
      EXPAND_BITS(AR_ADJUST_TABLE[HIGHBITS(slot->eg_phase,EG_DP_BITS-EG_BITS)],EG_BITS,EG_DP_BITS) ;

  slot->eg_mode = RELEASE ;
}

/* Channel key on */
INLINE static void keyOn(OPL *opl, e_int32 i)
{
  slotOn(opl->MOD(i)) ;
  slotOn(opl->CAR(i)) ;
  opl->ch[i]->key_status = 1 ;
}

/* Channel key off */
INLINE static void keyOff(OPL *opl, e_int32 i)
{
  slotOff(opl->MOD(i)) ;
  slotOff(opl->CAR(i)) ;
  opl->ch[i]->key_status = 0 ;
}

INLINE static void keyOn_BD(OPL *opl){ keyOn(opl,6) ; }
INLINE static void keyOn_SD(OPL *opl){ if(!opl->slot_on_flag[SLOT_SD]) slotOn(opl->CAR(7)) ; }
INLINE static void keyOn_TOM(OPL *opl){ if(!opl->slot_on_flag[SLOT_TOM]) slotOn(opl->MOD(8)) ; }
INLINE static void keyOn_HH(OPL *opl){ if(!opl->slot_on_flag[SLOT_HH]) slotOn(opl->MOD(7)) ; }
INLINE static void keyOn_CYM(OPL *opl){ if(!opl->slot_on_flag[SLOT_CYM]) slotOn(opl->CAR(8)) ; }
INLINE static void keyOff_BD(OPL *opl){ keyOff(opl,6) ; }
INLINE static void keyOff_SD(OPL *opl){ if(opl->slot_on_flag[SLOT_SD]) slotOff(opl->CAR(7)) ; }
INLINE static void keyOff_TOM(OPL *opl){ if(opl->slot_on_flag[SLOT_TOM]) slotOff(opl->MOD(8)) ; }
INLINE static void keyOff_HH(OPL *opl){ if(opl->slot_on_flag[SLOT_HH]) slotOff(opl->MOD(7)) ; }
INLINE static void keyOff_CYM(OPL *opl){ if(opl->slot_on_flag[SLOT_CYM]) slotOff(opl->CAR(8)) ; }

/* Set F-Number ( fnum : 10bit ) */
INLINE static void setFnumber(OPL *opl, e_int32 c, e_int32 fnum)
{
  opl->CAR(c)->fnum = fnum ;
  opl->MOD(c)->fnum = fnum ;
}

/* Set Block data (block : 3bit ) */
INLINE static void setBlock(OPL *opl, e_int32 c, e_int32 block)
{
  opl->CAR(c)->block = block ;
  opl->MOD(c)->block = block ;
}

/***********************************************************

                      Initializing

***********************************************************/

static void OPL_SLOT_reset(OPL_SLOT *slot)
{
  slot->sintbl = fullsintable ;
  slot->phase = 0 ;
  slot->dphase = 0 ;
  slot->output[0] = 0 ;
  slot->output[1] = 0 ;
  slot->feedback = 0 ;
  slot->eg_mode = FINISH ;
  slot->eg_phase = EG_DP_WIDTH ;
  slot->eg_dphase = 0 ;
  slot->rks = 0 ;
  slot->tll = 0 ;
  slot->fnum = 0 ;
  slot->block = 0 ;
  slot->pgout = 0 ;
  slot->egout = 0 ;
  memset(slot->patch,0,sizeof(OPL_PATCH)) ;
  UPDATE_ALL(slot) ;

}

static OPL_SLOT *OPL_SLOT_new(void)
{
  OPL_SLOT *slot ;
  OPL_PATCH *patch ;

  patch = malloc(sizeof(OPL_PATCH)) ;
  if(patch == NULL) return NULL ;

  slot = malloc(sizeof(OPL_SLOT)) ;
  if(slot == NULL)
  {
    free(patch) ;
    return NULL ;
  }
  
  slot->patch = patch ;
  return slot;
}

static void OPL_SLOT_delete(OPL_SLOT *slot)
{
  free(slot->patch) ;
  free(slot) ;
}

static void OPL_CH_reset(OPL_CH *ch)
{
  OPL_SLOT_reset(ch->mod) ;
  OPL_SLOT_reset(ch->car) ;
  ch->key_status = 0 ;
  ch->alg = 0 ;
}

static OPL_CH *OPL_CH_new(void)
{
  OPL_CH *ch ;
  OPL_SLOT *mod, *car ;

  mod = OPL_SLOT_new() ;
  if(mod == NULL) return NULL ;

  car = OPL_SLOT_new() ;
  if(car == NULL)
  {
    OPL_SLOT_delete(mod) ;
    return NULL ;
  }

  ch = malloc(sizeof(OPL_CH)) ;
  if(ch == NULL)
  {
    OPL_SLOT_delete(mod) ;
    OPL_SLOT_delete(car) ;
    return NULL ;
  }
  
  mod->type = 1 ;
  car->type = 1 ;
  ch->mod = mod ;
  ch->car = car ;

  OPL_CH_reset(ch) ;

  return ch ;
}

static void OPL_CH_delete(OPL_CH *ch)
{
  OPL_SLOT_delete(ch->mod) ;
  OPL_SLOT_delete(ch->car) ;
  free(ch) ;
}

OPL *OPL_new(void)
{
  OPL *opl ;
  OPL_CH *ch[9] ;
  e_int32 i, j ;

  opl = calloc(sizeof(OPL),1) ;
  if(opl == NULL) return NULL ;

  for( i = 0 ; i < 9 ; i++ )
  {
    ch[i] = OPL_CH_new() ;
    if(ch[i]==NULL)
    {
      for ( j = i ; i > 0 ; i++ ) OPL_CH_delete(ch[j-1]) ;
      free(opl) ;
      return NULL ;
    }
  }
  
  for ( i = 0 ; i < 9 ; i++)
  {
      opl->ch[i] = ch[i] ;
      opl->slot[i*2+0] = opl->ch[i]->mod ;
      opl->slot[i*2+1] = opl->ch[i]->car ;
  }

  for( i = 0 ; i < 10 ; i++ ) opl->mask[i] = 0 ;

  opl->adpcm = ADPCM_new() ;

  OPL_reset(opl) ;

  return opl ;
}

void OPL_delete(OPL *opl)
{
  e_int32 i ;

  ADPCM_delete(opl->adpcm) ;

  for ( i = 0 ; i < 9 ; i++ ) OPL_CH_delete(opl->ch[i]) ;
  free(opl) ;

}

/* Reset whole of opl except patch datas. */
void OPL_reset(OPL *opl)
{
  e_int32 i ;

  if(!opl) return ;

  for(i=0;i<9;i++) OPL_CH_reset(opl->ch[i]) ;

  opl->output[0] = 0 ;
  opl->output[1] = 0 ;

  opl->rythm_mode = 0 ;
  opl->am_mode = 0;
  opl->pm_mode = 0;
  opl->pm_phase = 0 ;
  opl->am_phase = 0 ;
  opl->noise_seed =0xffff ;

  for ( i = 0 ; i < 0xFF ; i++ ) opl->reg[i] = 0x00 ;
  for( i = 0 ; i < 18 ; i++ ) opl->slot_on_flag[i] = 0 ;

  ADPCM_reset(opl->adpcm);

}

void OPL_setClock(e_uint32 c, e_uint32 r)
{
  clk = c ;
  rate = r ;
  makeDphaseTable() ;
  makeDphaseARTable() ;
  makeDphaseDRTable() ;
  pm_dphase = (e_uint32)rate_adjust(PM_SPEED * PM_DP_WIDTH / (clk/72) ) ;
  am_dphase = (e_uint32)rate_adjust(AM_SPEED * AM_DP_WIDTH / (clk/72) ) ;
}

void OPL_init(e_uint32 c, e_uint32 r)
{
  makePmTable() ;
  makeAmTable() ;
  makeDB2LinTable() ;
  makeAdjustTable() ;
  makeTllTable() ;
  makeRksTable() ;
  makeSinTable() ;
  OPL_setClock(c,r) ;
  ADPCM_init(c,r);
}

void OPL_close(void)
{
  ADPCM_close();
}

/*********************************************************

                 Generate wave data

*********************************************************/
/* Convert Amp(0 to EG_HEIGHT) to Phase(0 to 4PI). */
#if ( SLOT_AMP_BITS - PG_BITS - 1 ) == 0
#define wave2_4pi(e)  (e)
#elif ( SLOT_AMP_BITS - PG_BITS - 1 ) > 0
#define wave2_4pi(e)  ( (e) >> ( SLOT_AMP_BITS - PG_BITS - 1 ))
#else
#define wave2_4pi(e)  ( (e) << ( 1 + PG_BITS - SLOT_AMP_BITS ))
#endif

/* Convert Amp(0 to EG_HEIGHT) to Phase(0 to 8PI). */
#if ( SLOT_AMP_BITS - PG_BITS - 2 ) == 0
#define wave2_8pi(e)  (e)
#elif ( SLOT_AMP_BITS - PG_BITS - 2 ) > 0
#define wave2_8pi(e)  ( (e) >> ( SLOT_AMP_BITS - PG_BITS - 2 ))
#else
#define wave2_8pi(e)  ( (e) << ( 2 + PG_BITS - SLOT_AMP_BITS ))
#endif

INLINE static e_uint32 mrand(e_uint32 seed)
{
  return ((seed>>15)^((seed>>12)&1)) | ((seed<<1)&0xffff) ;
}

INLINE static void update_noise(OPL *opl)
{
  opl->noise_seed = mrand(opl->noise_seed) ;
  whitenoise = opl->noise_seed & 1 ; 
}

INLINE static void update_ampm(OPL *opl)
{
  opl->pm_phase = (opl->pm_phase + pm_dphase)&(PM_DP_WIDTH - 1) ;
  opl->am_phase = (opl->am_phase + am_dphase)&(AM_DP_WIDTH - 1) ;
  lfo_am = amtable[opl->am_mode][HIGHBITS(opl->am_phase, AM_DP_BITS - AM_PG_BITS)] ;
  lfo_pm = pmtable[opl->pm_mode][HIGHBITS(opl->pm_phase, PM_DP_BITS - PM_PG_BITS)] ;
}

INLINE static e_uint32 calc_phase(OPL_SLOT *slot)
{
  if(slot->patch->PM)
    slot->phase += (slot->dphase * lfo_pm) >> PM_AMP_BITS ;
  else
    slot->phase += slot->dphase ;

  slot->phase &= (DP_WIDTH - 1) ;

  return HIGHBITS(slot->phase, DP_BASE_BITS) ;
}

INLINE static e_uint32 calc_envelope(OPL_SLOT *slot)
{
  #define S2E(x) (ALIGN((e_int32)(x/SL_STEP),SL_STEP,EG_STEP)<<(EG_DP_BITS-EG_BITS)) 
  static e_uint32 SL[16] = {
    S2E( 0), S2E( 3), S2E( 6), S2E( 9), S2E(12), S2E(15), S2E(18), S2E(21),
    S2E(24), S2E(27), S2E(30), S2E(33), S2E(36), S2E(39), S2E(42), S2E(93)
  } ;
  e_uint32 egout ;


  switch(slot->eg_mode)
  {

    case ATTACK:
      slot->eg_phase += slot->eg_dphase ;
      if(EG_DP_WIDTH & slot->eg_phase)
      {
        egout = 0 ;
        slot->eg_phase= 0 ;
        slot->eg_mode = DECAY ;
        UPDATE_EG(slot) ;
      }
      else
      {
        egout = AR_ADJUST_TABLE[HIGHBITS(slot->eg_phase, EG_DP_BITS - EG_BITS)] ;
      }
      break;

    case DECAY:
      slot->eg_phase += slot->eg_dphase ;
      egout = HIGHBITS(slot->eg_phase, EG_DP_BITS - EG_BITS) ;
      if(slot->eg_phase >= SL[slot->patch->SL])
      {
        if(slot->patch->EG)
        {
          slot->eg_phase = SL[slot->patch->SL] ;
	        slot->eg_mode = SUSHOLD ;
          UPDATE_EG(slot) ;
        }
        else
        {
          slot->eg_phase = SL[slot->patch->SL] ;
          slot->eg_mode = SUSTINE ;
          UPDATE_EG(slot) ;
        }
        egout = HIGHBITS(slot->eg_phase, EG_DP_BITS - EG_BITS) ;
      }
      break;

    case SUSHOLD:
      egout = HIGHBITS(slot->eg_phase, EG_DP_BITS - EG_BITS) ;
      if(slot->patch->EG == 0)
      {
        slot->eg_mode = SUSTINE ;
        UPDATE_EG(slot) ;
      }
      break;

    case SUSTINE:
    case RELEASE:
      slot->eg_phase += slot->eg_dphase ;
      egout = HIGHBITS(slot->eg_phase, EG_DP_BITS - EG_BITS) ; 
      if(egout >= (1<<EG_BITS))
      {
        slot->eg_mode = FINISH ;
        egout = (1<<EG_BITS) - 1 ;
      }
      break;

    case FINISH:
      egout = (1<<EG_BITS) - 1 ;
      break ;

    default:
      egout = (1<<EG_BITS) - 1 ;
      break;
    }

    if(slot->patch->AM) egout = ALIGN(egout+slot->tll,EG_STEP,DB_STEP) + lfo_am ;
    else egout = ALIGN(egout+slot->tll,EG_STEP,DB_STEP) ;

    if(egout>=DB_MUTE) egout = DB_MUTE-1;

    return egout ;
}

INLINE static e_int32 calc_slot_car(OPL_SLOT *slot, e_int32 fm)
{

  slot->egout = calc_envelope(slot) ; 
  slot->pgout = calc_phase(slot) ;
  if(slot->egout>=(DB_MUTE-1)) return 0 ;

  return DB2LIN_TABLE[slot->sintbl[(slot->pgout+wave2_8pi(fm))&(PG_WIDTH-1)] + slot->egout] ;

}

INLINE static e_int32 calc_slot_mod(OPL_SLOT *slot)
{

  e_int32 fm ;

  slot->output[1] = slot->output[0] ;
  slot->egout = calc_envelope(slot) ; 
  slot->pgout = calc_phase(slot) ;

  if(slot->egout>=(DB_MUTE-1)){
    slot->output[0] = 0 ;
  }else if(slot->patch->FB!=0){
    fm = wave2_4pi(slot->feedback) >> (7 - slot->patch->FB) ;
    slot->output[0] = DB2LIN_TABLE[slot->sintbl[(slot->pgout+fm)&(PG_WIDTH-1)] + slot->egout] ;
  }else
    slot->output[0] = DB2LIN_TABLE[slot->sintbl[slot->pgout] + slot->egout] ;

  slot->feedback = (slot->output[1] + slot->output[0])>>1 ;

  return slot->feedback ;

}

e_int16 OPL_calc(OPL *opl)
{

  e_int32 inst = 0 , perc = 0 , out = 0 ;
  e_int32 i ;

  update_ampm(opl) ;
  update_noise(opl) ;      

  for(i=0 ; i < 6 ; i++)
  {
    if((!opl->mask[i])&&(opl->CAR(i)->eg_mode!=FINISH))
    {
      if(opl->ch[i]->alg)
        inst += calc_slot_car(opl->CAR(i),0) + calc_slot_mod(opl->MOD(i)) ;
      else
        inst += calc_slot_car(opl->CAR(i),calc_slot_mod(opl->MOD(i))) ;
    }
  }

  if(!opl->rythm_mode)
  {
    for(i=6 ; i < 9 ; i++)
    {
      if((!opl->mask[i])&&(opl->CAR(i)->eg_mode!=FINISH))
      {
        if(opl->ch[i]->alg)
          inst += calc_slot_car(opl->CAR(i),0) + calc_slot_mod(opl->MOD(i)) ;
        else
          inst += calc_slot_car(opl->CAR(i),calc_slot_mod(opl->MOD(i))) ;
      }
    }
  }

  out = inst + perc + ADPCM_calc(opl->adpcm);

  if(out>32767) return 32767 ;
  if(out<-32768) return -32768 ;

  return (e_int16)out ;

}

void OPL_writeReg(OPL *opl, e_uint32 reg, e_uint32 data)
{

  e_int32 s,c ;

  e_int32 stbl[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 } ;

  data = data&0xff ;
  reg = reg&0xff ;


  if((0x07<=reg)&&(reg<=0x12))
    ADPCM_writeReg(opl->adpcm, reg, data);
  else if((0x20<=reg)&&(reg<0x40))
  {
    s = stbl[(reg-0x20)] ;
    if(s >= 0)
    {
      opl->slot[s]->patch->AM = (data>>7)&1 ;
      opl->slot[s]->patch->PM = (data>>6)&1 ;
      opl->slot[s]->patch->EG = (data>>5)&1 ;
      opl->slot[s]->patch->KR = (data>>4)&1 ;
      opl->slot[s]->patch->ML = (data)&15 ;
      UPDATE_ALL(opl->slot[s]) ;
    }
  }
  else if((0x40<=reg)&&(reg<0x60))
  {

    s = stbl[(reg-0x40)] ;
    if(s>=0)
    {
      opl->slot[s]->patch->KL = (data>>6)&3 ;
      opl->slot[s]->patch->TL = (data)&63 ;
      UPDATE_ALL(opl->slot[s]) ;
    }

  }
  else if((0x60<=reg)&&(reg<0x80))
  {

    s = stbl[(reg-0x60)] ;
    if(s>=0)
    {
      opl->slot[s]->patch->AR = (data>>4)&15 ;
      opl->slot[s]->patch->DR = (data)&15 ;
      UPDATE_EG(opl->slot[s]) ;
    }
     
  }
  else if((0x80<=reg)&&(reg<0xA0))
  {
    s = stbl[(reg-0x80)] ;
    if(s>=0)
    {
      opl->slot[s]->patch->SL = (data>>4)&15 ;
      opl->slot[s]->patch->RR = (data)&15 ;
      UPDATE_EG(opl->slot[s]) ;
    }
  }
  else if((0xA0<=reg)&&(reg<0xA9))
  {
    c=reg-0xA0 ;
    if(c>=0)
    {
      setFnumber(opl, c, data + ((opl->reg[reg+0x10]&3)<<8)) ;
      UPDATE_ALL(opl->CAR(c)) ;
      UPDATE_ALL(opl->MOD(c)) ;
    }

  }
  else if((0xB0<=reg)&&(reg<0xB9))
  {

    c=reg-0xB0 ;
    if(c>=0)
    {
      setFnumber(opl, c, ((data&3)<<8) + opl->reg[reg-0x10]) ;
      setBlock(opl, c, (data>>2)&7 ) ;
      
      if(((opl->reg[reg]&0x20)==0)&&(data&0x20)) keyOn(opl, c) ; 
      else if((data&0x20)==0) keyOff(opl, c) ;

      UPDATE_ALL(opl->MOD(c)) ;
      UPDATE_ALL(opl->CAR(c)) ;
    }

  }
  else if((0xC0<=reg)&&(reg<0xC9))
  {

    c=reg-0xC0 ;
    if(c>=0)
    {
      opl->slot[c*2]->patch->FB = (data>>1)&7 ;
      opl->ch[c]->alg = data&1 ;
    }
    
  }
  else if(reg==0xbd)
  {
    opl->rythm_mode = data & 32 ;
    opl->am_mode = (data>>7)&1 ;
    opl->pm_mode = (data>>6)&1 ;
  }

  opl->reg[reg] = (unsigned char)data ;

}

e_uint32 OPL_readIO(OPL *opl)
{
  return opl->reg[opl->adr] ;
}

void OPL_writeIO(OPL *opl, e_uint32 adr, e_uint32 val)
{
  adr &= 0xff ;
  if(adr & 1) OPL_writeReg(opl, opl->adr, val) ;
  else opl->adr = val ;
}

e_uint32 OPL_status(OPL *opl)
{
  return ADPCM_status(opl->adpcm);
}