/***************************************************************************
 fmopl.c Copyright (C) 1999-2000 Tatsuyuki Satoh
 		       2001-2004 The ScummVM project
 		       2002 Solomon Peachy
 		       2004 Walter van Niftrik

 This program may be modified and copied freely according to the terms of
 the GNU general public license (GPL), as long as the above copyright
 notice and the licensing information contained herein are preserved.

 Please refer to www.gnu.org for licensing details.

 This work is provided AS IS, without warranty of any kind, expressed or
 implied, including but not limited to the warranties of merchantibility,
 noninfringement, and fitness for a specific purpose. The author will not
 be held liable for any damage caused by this work or derivatives of it.

 By using this source code, you agree to the licensing terms as stated
 above.

 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 /* HAVE_CONFIG_H */

#ifndef INLINE
#	ifdef _MSC_VER
#		define INLINE __inline
#	else
#		define INLINE inline
#	endif
#endif

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <math.h>

#include "fmopl.h"

#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 */
int ENV_BITS;
/* envelope output entries */
int EG_ENT;

/* used dynamic memory = EG_ENT*4*4(byte)or EG_ENT*6*4(byte) */
/* used static  memory = EG_ENT*4 (byte)                     */
int EG_OFF;								 /* OFF */
int EG_DED;
int EG_DST;								 /* DECAY START */
int EG_AED;
#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,
#ifdef TWELVE_VOICE
	18,20,22,19,21,23,-1,-1
#else
	-1,-1,-1,-1,-1,-1,-1,-1
#endif
};

static guint32 KSL_TABLE[8 * 16];

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

/* 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)*/

static int SL_TABLE[16];

static const guint32 SL_TABLE_SEED[16] = {
	0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 31
};

#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];
static int ENV_CURVE[2 * 4096 + 1];   // to keep it static ...

/* multiple table */
#define ML(a) (int)(a * 2)
static const guint32 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 */

/* --------------------- rebuild tables ------------------- */

#define SC_KSL(mydb) ((guint32) (mydb / (EG_STEP / 2)))
#define SC_SL(db) (int)(db * ((3 / EG_STEP) * (1 << ENV_BITS))) + EG_DST

void OPLBuildTables(int ENV_BITS_PARAM, int EG_ENT_PARAM) {
	int i;

	ENV_BITS = ENV_BITS_PARAM;
	EG_ENT = EG_ENT_PARAM;
	EG_OFF = ((2 * EG_ENT)<<ENV_BITS);  /* OFF          */
	EG_DED = EG_OFF;
	EG_DST = (EG_ENT << ENV_BITS);     /* DECAY  START */
	EG_AED = EG_DST;
	//EG_STEP = (96.0/EG_ENT);

	for (i = 0; i < (int)(sizeof(KSL_TABLE_SEED) / sizeof(double)); i++)
		KSL_TABLE[i] = SC_KSL(KSL_TABLE_SEED[i]);

	for (i = 0; i < (int)(sizeof(SL_TABLE_SEED) / sizeof(guint32)); i++)
		SL_TABLE[i] = SC_SL(SL_TABLE_SEED[i]);
}

#undef SC_KSL
#undef SC_SL

/* --------------------- 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 guint32 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) {
	guint32 env_out;
	OPL_SLOT *SLOT;

	feedback2 = 0;
	/* SLOT 1 */
	SLOT = &CH->SLOT[SLOT1];
	env_out=OPL_CALC_SLOT(SLOT);
	if(env_out < (guint32)(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 < (guint32)(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) {
	guint32 env_tam, env_sd, env_top, env_hh;
	int whitenoise = (int)((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 < (guint32)(EG_ENT - 1))
		outd[0] += OP_OUT(SLOT7_1, env_sd, 0) * 8;
	/* TAM */
	if(env_tam < (guint32)(EG_ENT - 1))
		outd[0] += OP_OUT(SLOT8_1, env_tam, 0) * 2;
	/* TOP-CY */
	if(env_top < (guint32)(EG_ENT - 1))
		outd[0] += OP_OUT(SLOT7_2, env_top, tone8) * 2;
	/* HH */
	if(env_hh  < (guint32)(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 < 75; 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) / pow(10.0, 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 = sin(2 * PI * s / SIN_ENT); /* sin     */
		pom = 20 * 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 = 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 + 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 * 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] = (guint32)(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;
	guint32 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*/
				guint8 st1 = v & 1;
				guint8 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 */
			{
			guint8 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) >= ADLIB_VOICES)
			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) >= ADLIB_VOICES)
			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, gint16 *buffer, int length, int interleave) {
	int i;
	int data;
	gint16 *buf = buffer;
	guint32 amsCnt = OPL->amsCnt;
	guint32 vibCnt = OPL->vibCnt;
	guint8 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);
#ifdef TWELVE_VOICE
		for(CH=&S_CH[9]; CH < &S_CH[ADLIB_VOICES]; CH++)
			OPL_CALC_CH(CH);
#endif
		/* limit check */
		data = Limit(outd[0], OPL_MAXOUT, OPL_MINOUT);
		/* store to sound buffer */
		buf[i << interleave] = 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 parameter */
	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;
#ifdef TWELVE_VOICE
	int max_ch = 12;
#else
	int max_ch = 9; /* normaly 9 channels */
#endif

	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 *)calloc(state_size, 1);
	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 */
		fprintf(stderr, "OPL:read unmapped KEYBOARD port\n");
		return 0;
	case 0x19: /* I/O DATA    */
		fprintf(stderr, "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;
}