fm.c

十七种模拟器源代码 非常有用的作课程设计不可缺少的

		TL_TABLE[       t] =  (int)rate;
		TL_TABLE[TL_MAX+t] = -TL_TABLE[t];
/*		LOG(LOG_INF,("TotalLevel(%3d) = %x\n",t,TL_TABLE[t]));*/
	}

	/* make sinwave table (pointer of total level) */
	for (s = 1;s <= SIN_ENT/4;s++){
		pom = sin(2.0*PI*s/SIN_ENT); /* sin   */
		pom = 20*log10(1/pom);	     /* -> decibel */
		j = (int)(pom / EG_STEP);    /* TL_TABLE steps */
		/* cut off check */
		if(j > PG_CUT_OFF)
			j = PG_CUT_OFF;
		/* 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];
		/* LOG(LOG_INF,("sin(%3d) = %f:%f db\n",s,pom,(double)j * EG_STEP)); */
	}
	/* degree 0 = degree 180                   = off */
	SIN_TABLE[0] = SIN_TABLE[SIN_ENT/2]        = &TL_TABLE[PG_CUT_OFF];

	/* envelope counter -> envelope output table */
	for (i=0; i<EG_ENT; i++)
	{
		/* ATTACK curve */
		/* !!!!! preliminary !!!!! */
		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;
#if FM_SEG_SUPPORT
		/* DECAY UPSIDE (SSG ENV) */
		ENV_CURVE[(EG_UST>>ENV_BITS)+i]= EG_ENT-1-i;
#endif
	}
	/* off */
	ENV_CURVE[EG_OFF>>ENV_BITS]= EG_ENT-1;

	/* decay to reattack envelope converttable */
	j = EG_ENT-1;
	for (i=0; i<EG_ENT; i++)
	{
		while( j && (ENV_CURVE[j] < i) ) j--;
		DRAR_TABLE[i] = j<<ENV_BITS;
		/* LOG(LOG_INF,("DR %06X = %06X,AR=%06X\n",i,DRAR_TABLE[i],ENV_CURVE[DRAR_TABLE[i]>>ENV_BITS] )); */
	}
	return 1;
}


static void FMCloseTable( void )
{
	if( TL_TABLE ) free( TL_TABLE );
	return;
}

/* OPN/OPM Mode  Register Write */
INLINE void FMSetMode( FM_ST *ST ,int n,int v )
{
	/* b7 = CSM MODE */
	/* b6 = 3 slot mode */
	/* b5 = reset b */
	/* b4 = reset a */
	/* b3 = timer enable b */
	/* b2 = timer enable a */
	/* b1 = load b */
	/* b0 = load a */
	ST->mode = v;

	/* reset Timer b flag */
	if( v & 0x20 )
		FM_STATUS_RESET(ST,0x02);
	/* reset Timer a flag */
	if( v & 0x10 )
		FM_STATUS_RESET(ST,0x01);
	/* load b */
	if( v & 0x02 )
	{
		if( ST->TBC == 0 )
		{
			ST->TBC = ( 256-ST->TB)<<4;
			/* External timer handler */
			if (ST->Timer_Handler) (ST->Timer_Handler)(n,1,ST->TBC,ST->TimerBase);
		}
	}else if (ST->timermodel == FM_TIMER_INTERVAL)
	{	/* stop interbval timer */
		if( ST->TBC != 0 )
		{
			ST->TBC = 0;
			if (ST->Timer_Handler) (ST->Timer_Handler)(n,1,0,ST->TimerBase);
		}
	}
	/* load a */
	if( v & 0x01 )
	{
		if( ST->TAC == 0 )
		{
			ST->TAC = (1024-ST->TA);
			/* External timer handler */
			if (ST->Timer_Handler) (ST->Timer_Handler)(n,0,ST->TAC,ST->TimerBase);
		}
	}else if (ST->timermodel == FM_TIMER_INTERVAL)
	{	/* stop interbval timer */
		if( ST->TAC != 0 )
		{
			ST->TAC = 0;
			if (ST->Timer_Handler) (ST->Timer_Handler)(n,0,0,ST->TimerBase);
		}
	}
}

/* Timer A Overflow */
INLINE void TimerAOver(FM_ST *ST)
{
	/* status set if enabled */
	if(ST->mode & 0x04) FM_STATUS_SET(ST,0x01);
	/* clear or reload the counter */
	if (ST->timermodel == FM_TIMER_INTERVAL)
	{
		ST->TAC = (1024-ST->TA);
		if (ST->Timer_Handler) (ST->Timer_Handler)(ST->index,0,ST->TAC,ST->TimerBase);
	}
	else ST->TAC = 0;
}
/* Timer B Overflow */
INLINE void TimerBOver(FM_ST *ST)
{
	/* status set if enabled */
	if(ST->mode & 0x08) FM_STATUS_SET(ST,0x02);
	/* clear or reload the counter */
	if (ST->timermodel == FM_TIMER_INTERVAL)
	{
		ST->TBC = ( 256-ST->TB)<<4;
		if (ST->Timer_Handler) (ST->Timer_Handler)(ST->index,1,ST->TBC,ST->TimerBase);
	}
	else ST->TBC = 0;
}
/* CSM Key Controll */
INLINE void CSMKeyControll(FM_CH *CH)
{
	/* all key off */
	/* FM_KEYOFF(CH,SLOT1); */
	/* FM_KEYOFF(CH,SLOT2); */
	/* FM_KEYOFF(CH,SLOT3); */
	/* FM_KEYOFF(CH,SLOT4); */
	/* total level latch */
	CH->SLOT[SLOT1].TLL = CH->SLOT[SLOT1].TL;
	CH->SLOT[SLOT2].TLL = CH->SLOT[SLOT2].TL;
	CH->SLOT[SLOT3].TLL = CH->SLOT[SLOT3].TL;
	CH->SLOT[SLOT4].TLL = CH->SLOT[SLOT4].TL;
	/* all key on */
	FM_KEYON(CH,SLOT1);
	FM_KEYON(CH,SLOT2);
	FM_KEYON(CH,SLOT3);
	FM_KEYON(CH,SLOT4);
}

#if BUILD_OPN
/***********************************************************/
/* OPN unit                                                */
/***********************************************************/

/* OPN 3slot struct */
typedef struct opn_3slot {
	UINT32  fc[3];		/* fnum3,blk3  :calcrated */
	UINT8 fn_h[3];		/* freq3 latch            */
	UINT8 kcode[3];		/* key code    :          */
}FM_3SLOT;

/* OPN/A/B common state */
typedef struct opn_f {
	UINT8 type;		/* chip type         */
	FM_ST ST;				/* general state     */
	FM_3SLOT SL3;			/* 3 slot mode state */
	FM_CH *P_CH;			/* pointer of CH     */
	UINT32 FN_TABLE[2048]; /* fnumber -> increment counter */
#if FM_LFO_SUPPORT
	/* LFO */
	UINT32 LFOCnt;
	UINT32 LFOIncr;
	UINT32 LFO_FREQ[8];/* LFO FREQ table */
#endif
} FM_OPN;

/* OPN key frequency number -> key code follow table */
/* fnum higher 4bit -> keycode lower 2bit */
static const UINT8 OPN_FKTABLE[16]={0,0,0,0,0,0,0,1,2,3,3,3,3,3,3,3};

#if FM_LFO_SUPPORT
/* OPN LFO waveform table */
static INT32 OPN_LFO_wave[LFO_ENT];
#endif

static int OPNInitTable(void)
{
	int i;

#if FM_LFO_SUPPORT
	/* LFO wave table */
	for(i=0;i<LFO_ENT;i++)
	{
		OPN_LFO_wave[i]= i<LFO_ENT/2 ? i*LFO_RATE/(LFO_ENT/2) : (LFO_ENT-i)*LFO_RATE/(LFO_ENT/2);
	}
#endif
	return FMInitTable();
}

/* ---------- priscaler set(and make time tables) ---------- */
static void OPNSetPris(FM_OPN *OPN , int pris , int TimerPris, int SSGpris)
{
	int i;

	/* frequency base */
	
	OPN->ST.freqbase = (OPN->ST.rate) ? ((double)OPN->ST.clock / OPN->ST.rate) / pris : 0;
	/* Timer base time */
	OPN->ST.TimerBase = 1.0/((double)OPN->ST.clock / (double)TimerPris);
	/* SSG part  priscaler set */
	if( SSGpris ) SSGClk( OPN->ST.index, OPN->ST.clock * 2 / SSGpris );
	/* make time tables */
	init_timetables( &OPN->ST , OPN_DTTABLE , OPN_ARRATE , OPN_DRRATE );
	/* make fnumber -> increment counter table */
	for( i=0 ; i < 2048 ; i++ )
	{
		/* it is freq table for octave 7 */
		/* opn freq counter = 20bit */
		OPN->FN_TABLE[i] = (UINT32)( (double)i * OPN->ST.freqbase * FREQ_RATE * (1<<7) / 2 );
	}
#if FM_LFO_SUPPORT
	/* LFO freq. table */
	{
		/* 3.98Hz,5.56Hz,6.02Hz,6.37Hz,6.88Hz,9.63Hz,48.1Hz,72.2Hz @ 8MHz */
#define FM_LF(Hz) ((double)LFO_ENT*(1<<LFO_SHIFT)*(Hz)/(8000000.0/144))
		static const double freq_table[8] = { FM_LF(3.98),FM_LF(5.56),FM_LF(6.02),FM_LF(6.37),FM_LF(6.88),FM_LF(9.63),FM_LF(48.1),FM_LF(72.2) };
#undef FM_LF
		for(i=0;i<8;i++)
		{
			OPN->LFO_FREQ[i] = (UINT32)(freq_table[i] * OPN->ST.freqbase);
		}
	}
#endif
/*	LOG(LOG_INF,("OPN %d set priscaler %d\n",OPN->ST.index,pris));*/
}

/* ---------- write a OPN mode register 0x20-0x2f ---------- */
static void OPNWriteMode(FM_OPN *OPN, int r, int v)
{
	UINT8 c;
	FM_CH *CH;

	switch(r){
	case 0x21:	/* Test */
		break;
#if FM_LFO_SUPPORT
	case 0x22:	/* LFO FREQ (YM2608/YM2612) */
		if( OPN->type & TYPE_LFOPAN )
		{
			OPN->LFOIncr = (v&0x08) ? OPN->LFO_FREQ[v&7] : 0;
			cur_chip = NULL;
		}
		break;
#endif
	case 0x24:	/* timer A High 8*/
		OPN->ST.TA = (OPN->ST.TA & 0x03)|(((int)v)<<2);
		break;
	case 0x25:	/* timer A Low 2*/
		OPN->ST.TA = (OPN->ST.TA & 0x3fc)|(v&3);
		break;
	case 0x26:	/* timer B */
		OPN->ST.TB = v;
		break;
	case 0x27:	/* mode , timer controll */
		FMSetMode( &(OPN->ST),OPN->ST.index,v );
		break;
	case 0x28:	/* key on / off */
		c = v&0x03;
		if( c == 3 ) break;
		if( (v&0x04) && (OPN->type & TYPE_6CH) ) c+=3;
		CH = OPN->P_CH;
		CH = &CH[c];
		/* csm mode */
		/* if( c == 2 && (OPN->ST.mode & 0x80) ) break; */
		if(v&0x10) FM_KEYON(CH,SLOT1); else FM_KEYOFF(CH,SLOT1);
		if(v&0x20) FM_KEYON(CH,SLOT2); else FM_KEYOFF(CH,SLOT2);
		if(v&0x40) FM_KEYON(CH,SLOT3); else FM_KEYOFF(CH,SLOT3);
		if(v&0x80) FM_KEYON(CH,SLOT4); else FM_KEYOFF(CH,SLOT4);
/*		LOG(LOG_INF,("OPN %d:%d : KEY %02X\n",n,c,v&0xf0));*/
		break;
	}
}

/* ---------- write a OPN register (0x30-0xff) ---------- */
static void OPNWriteReg(FM_OPN *OPN, int r, int v)
{
	UINT8 c;
	FM_CH *CH;
	FM_SLOT *SLOT;

	/* 0x30 - 0xff */
	if( (c = OPN_CHAN(r)) == 3 ) return; /* 0xX3,0xX7,0xXB,0xXF */
	if( (r >= 0x100) /* && (OPN->type & TYPE_6CH) */ ) c+=3;
		CH = OPN->P_CH;
		CH = &CH[c];

	SLOT = &(CH->SLOT[OPN_SLOT(r)]);
	switch( r & 0xf0 ) {
	case 0x30:	/* DET , MUL */
		set_det_mul(&OPN->ST,CH,SLOT,v);
		break;
	case 0x40:	/* TL */
		set_tl(CH,SLOT,v,(c == 2) && (OPN->ST.mode & 0x80) );
		break;
	case 0x50:	/* KS, AR */
		set_ar_ksr(CH,SLOT,v,OPN->ST.AR_TABLE);
		break;
	case 0x60:	/*     DR */
		/* bit7 = AMS_ON ENABLE(YM2612) */
		set_dr(SLOT,v,OPN->ST.DR_TABLE);
#if FM_LFO_SUPPORT
		if( OPN->type & TYPE_LFOPAN)
		{
			SLOT->amon = v>>7;
			SLOT->ams = CH->ams * SLOT->amon;
		}
#endif
		break;
	case 0x70:	/*     SR */
		set_sr(SLOT,v,OPN->ST.DR_TABLE);
		break;
	case 0x80:	/* SL, RR */
		set_sl_rr(SLOT,v,OPN->ST.DR_TABLE);
		break;
	case 0x90:	/* SSG-EG */
/* #if !FM_SEG_SUPPORT */
/* 		if(v&0x08) LOG(LOG_ERR,("OPN %d,%d,%d :SSG-TYPE envelope selected (not supported )\n",OPN->ST.index,c,OPN_SLOT(r))); */
/* #endif */
		SLOT->SEG = v&0x0f;
		break;
	case 0xa0:
		switch( OPN_SLOT(r) ){
		case 0:		/* 0xa0-0xa2 : FNUM1 */
			{
				UINT32 fn  = (((UINT32)( (CH->fn_h)&7))<<8) + v;
				UINT8 blk = CH->fn_h>>3;
				/* make keyscale code */
				CH->kcode = (blk<<2)|OPN_FKTABLE[(fn>>7)];
				/* make basic increment counter 32bit = 1 cycle */
				CH->fc = OPN->FN_TABLE[fn]>>(7-blk);
				CH->SLOT[SLOT1].Incr=-1;
			}
			break;
		case 1:		/* 0xa4-0xa6 : FNUM2,BLK */
			CH->fn_h = v&0x3f;
			break;
		case 2:		/* 0xa8-0xaa : 3CH FNUM1 */
			if( r < 0x100)
			{
				UINT32 fn  = (((UINT32)(OPN->SL3.fn_h[c]&7))<<8) + v;
				UINT8 blk = OPN->SL3.fn_h[c]>>3;
				/* make keyscale code */
				OPN->SL3.kcode[c]= (blk<<2)|OPN_FKTABLE[(fn>>7)];
				/* make basic increment counter 32bit = 1 cycle */
				OPN->SL3.fc[c] = OPN->FN_TABLE[fn]>>(7-blk);
				(OPN->P_CH)[2].SLOT[SLOT1].Incr=-1;
			}
			break;
		case 3:		/* 0xac-0xae : 3CH FNUM2,BLK */
			if( r < 0x100)
				OPN->SL3.fn_h[c] = v&0x3f;
			break;
		}
		break;
	case 0xb0:
		switch( OPN_SLOT(r) ){
		case 0:		/* 0xb0-0xb2 : FB,ALGO */
			{
				int feedback = (v>>3)&7;
				CH->ALGO = v&7;
				CH->FB   = feedback ? 8+1 - feedback : 0;
				setup_connection( CH );
			}
			break;
		case 1:		/* 0xb4-0xb6 : L , R , AMS , PMS (YM2612/YM2608) */
			if( OPN->type & TYPE_LFOPAN)
			{
#if FM_LFO_SUPPORT
				/* b0-2 PMS */
				/* 0,3.4,6.7,10,14,20,40,80(cent) */
				static const double pmd_table[8]={0,3.4,6.7,10,14,20,40,80};
				static const int amd_table[4]={(int)(0/EG_STEP),(int)(1.4/EG_STEP),(int)(5.9/EG_STEP),(int)(11.8/EG_STEP) };
				CH->pms = (INT32)( (1.5/1200.0)*pmd_table[v & 7] * PMS_RATE);
				/* b4-5 AMS */
				/* 0 , 1.4 , 5.9 , 11.8(dB) */
				CH->ams = amd_table[(v>>4) & 0x03];
				CH->SLOT[SLOT1].ams = CH->ams * CH->SLOT[SLOT1].amon;
				CH->SLOT[SLOT2].ams = CH->ams * CH->SLOT[SLOT2].amon;
				CH->SLOT[SLOT3].ams = CH->ams * CH->SLOT[SLOT3].amon;
				CH->SLOT[SLOT4].ams = CH->ams * CH->SLOT[SLOT4].amon;
#endif
				/* PAN */
				CH->PAN = (v>>6)&0x03; /* PAN : b6 = R , b7 = L */
				setup_connection( CH );
				/* LOG(LOG_INF,("OPN %d,%d : PAN %d\n",n,c,CH->PAN));*/
			}
			break;
		}
		break;
	}
}
#endif /* BUILD_OPN */

#if BUILD_YM2203
/*******************************************************************************/
/*		YM2203 local section                                                   */
/*******************************************************************************/

/* here's the virtual YM2203(OPN) */
typedef struct ym2203_f {
	FM_OPN OPN;				/* OPN state         */
	FM_CH CH[3];			/* channel state     */
} YM2203;

static YM2203 *FM2203=NULL;	/* array of YM2203's */
static int YM2203NumChips;	/* total chip */

/* ---------- update one of chip ----------- */
void YM2203UpdateOne(int num, INT16 *buffer, int length)
{
	YM2203 *F2203 = &(FM2203[num]);
	FM_OPN *OPN =   &(FM2203[num].OPN);
	int i;
	FM_CH *ch;
	FMSAMPLE *buf = buffer;

	cur_chip = (void *)F2203;
	State = &F2203->OPN.ST;
	cch[0]   = &F2203->CH[0];
	cch[1]   = &F2203->CH[1];
	cch[2]   = &F2203->CH[2];
#if FM_LFO_SUPPORT
	/* LFO */
	lfo_amd = lfo_pmd = 0;
#endif
	/* frequency counter channel A */
	OPN_CALC_FCOUNT( cch[0] );
	/* frequency counter channel B */
	OPN_CALC_FCOUNT( cch[1] );
	/* frequency counter channel C */
	if( (State->mode & 0xc0) ){
		/* 3SLOT MODE */
		if( cch[2]->SLOT[SLOT1].Incr==-1){
			/* 3 slot mode */
			CALC_FCSLOT(&cch[2]->SLOT[SLOT1] , OPN->SL3.fc[1] , OPN->SL3.kcode[1] );
			CALC_FCSLOT(&cch[2]->SLOT[SLOT2] , OPN->SL3.fc[2] , OPN->SL3.kcode[2] );
			CALC_FCSLOT(&cch[2]->SLOT[SLOT3] , OPN->SL3.fc[0] , OPN->SL3.kcode[0] );
			CALC_FCSLOT(&cch[2]->SLOT[SLOT4] , cch[2]->fc , cch[2]->kcode );
		}
	}else OPN_CALC_FCOUNT( cch[2] );

    for( i=0; i < length ; i++ )
	{
		/*            channel A         channel B         channel C      */
		out_ch[OUTD_CENTER] = 0;
		/* calcrate FM */
		for( ch=cch[0] ; ch <= cch[2] ; ch++)
			FM_CALC_CH( ch );