Function Y8950UpdateOne

src/Engine/Adlib/fmopl.cpp:1102–1159

#if BUILD_Y8950

void Y8950UpdateOne(FM_OPL *OPL, INT16 *buffer, int length)
{
    int i;
	int data;
	OPLSAMPLE *buf = buffer;
	UINT32 amsCnt  = OPL->amsCnt;
	UINT32 vibCnt  = OPL->vibCnt;
	UINT8 rythm = OPL->rythm&0x20;
	OPL_CH *CH,*R_CH;
	YM_DELTAT *DELTAT = OPL->deltat;

	/* setup DELTA-T unit */
	YM_DELTAT_DECODE_PRESET(DELTAT);

	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;
		/* deltaT ADPCM */
		if( DELTAT->portstate )
			YM_DELTAT_ADPCM_CALC(DELTAT);
		/* FM part */
		for(CH=S_CH ; CH < R_CH ; CH++)
			OPL_CALC_CH(CH);
		/* Rythm 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;
	/* deltaT START flag */
	if( !DELTAT->portstate )
		OPL->status &= 0xfe;
}