dsp.c

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

		Copyright (c) 2003 Brad Martin.

This file is part of OpenSPC.

OpenSPC is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

OpenSPC 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 Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License
along with OpenSPC; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA



dsp.c: implements functions that emulate the DSP part of the SPC chip.
Some of these functions cannot be static because the SPC core needs access
to them, however they are not intended for external library use, and their
specific implementations and prototypes are subject to change.

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

#undef DEBUG
#undef DBG_KEY
#undef DBG_ENV
#undef DBG_PMOD
#undef DBG_BRR
#undef DBG_ECHO
#undef DBG_INTRP

#undef NO_PMOD
#undef NO_ECHO

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

#include "SPCimpl.h"
#include "dsp.h"
#include "gauss.h"

/**** Global Variables :P ****/
int keyed_on,keys;	/* 8-bits for 8 voices */
struct voice_state voice_state[8];

/* These are for the FIR echo filter */
#ifndef NO_ECHO
static short FIRlbuf[8],FIRrbuf[8];
static int FIRptr,echo_ptr;
#endif

/* Noise stuff */
int noise_cnt,noise_lev;

static const int *G1=&gauss[256],
                 *G2=&gauss[512],
                 *G3=&gauss[255],
                 *G4=&gauss[-1];	/* Ptrs to Gaussian table */

static const int mask=0xFF;

/* Original SPC DSP took samples 32000 times a second, which is once every
   (2048000/32000 = 64) cycles. */
const int TS_CYC=1024000/32000;

/* This table is for envelope timing.  It represents the number of counts
   that should be subtracted from the counter each sample period (32kHz). 
   The counter starts at 30720 (0x7800). */
static const int CNT_INIT=0x7800, ENVCNT[0x20]={
 0x0000,0x000F,0x0014,0x0018,0x001E,0x0028,0x0030,0x003C,
 0x0050,0x0060,0x0078,0x00A0,0x00C0,0x00F0,0x0140,0x0180,
 0x01E0,0x0280,0x0300,0x03C0,0x0500,0x0600,0x0780,0x0A00,
 0x0C00,0x0F00,0x1400,0x1800,0x1E00,0x2800,0x3C00,0x7800};

/**** Some macros ****/

/* make reading the ADSR code easier */

#define SL(v) (DSPregs[((v)<<4)+6]>>5)		/* Returns SUSTAIN level */
#define SR(v) (DSPregs[((v)<<4)+6]&0x1F)	/* Returns SUSTAIN rate */

/* handle endianness */
#ifdef WORDS_BIGENDIAN
#define LEtoME16(x) ((((x) >> 8) & 0xFF) | (((x) << 8) & 0xFF00))
#define MEtoLE16(x) ((((x) >> 8) & 0xFF) | (((x) << 8) & 0xFF00))
#else
#define LEtoME16(x) (x)
#define MEtoLE16(x) (x)
#endif

/**** Static functions ****/

static int AdvanceEnvelope(int v)	/* Return value is current ENVX */
{
	int envx=voice_state[v].envx,
	    cnt,adsr1,t;
	if(voice_state[v].envstate==RELEASE)
	{
		/* Docs: "When in the state of "key off". the "click" sound
		   is prevented by the addition of the fixed value 1/256"
		   WTF???  Alright, I'm going to choose to interpret that
		   this way:  When a note is keyed off, start the RELEASE
		   state, which subtracts 1/256th each sample period
		   (32kHz).  Note there's no need for a count because it
		   always happens every update. */
		envx-=0x8;  /* 0x8 / 0x800 = 1/256th */
		if(envx<=0)
		{
			envx=0;
			keys&=~(1<<v); 
			return -1; 
		}
		voice_state[v].envx=envx;
		DSPregs[(v<<4)+8]=envx>>8;
#ifdef DBG_ENV
fprintf(stderr,"ENV voice %d: envx=%03X, state=RELEASE\n",v,envx);
#endif
		return envx;
	}
	cnt=voice_state[v].envcnt;
	adsr1=DSPregs[(v<<4)+5];
	if(adsr1&0x80) switch(voice_state[v].envstate)
	{
	case ATTACK:
		/* Docs are very confusing.  "AR is multiplied by the fixed
		   value 1/64..."  I believe it means to add 1/64th to ENVX
		   once every time ATTACK is updated, and that's what I'm
		   going to implement. */
		t=adsr1&0xF;
		if(t==0xF)
		{
#ifdef DBG_ENV
fprintf(stderr,"ENV voice %d: instant attack\n",v);
#endif
			envx+=0x400;
		}
		else
		{
			cnt-=ENVCNT[(t<<1)+1];
			if(cnt>0)
				break;
			envx+=0x20; /* 0x020 / 0x800 = 1/64 */
			cnt=CNT_INIT;
		}
		if(envx>0x7FF)
		{
			envx=0x7FF;
			voice_state[v].envstate=DECAY;
		}
#ifdef DBG_ENV
fprintf(stderr,"ENV voice %d: envx=%03X, state=ATTACK\n",v,envx);
#endif
		voice_state[v].envx=envx;
		break;
	case DECAY:
		/* Docs: "DR... [is multiplied] by the fixed value 1-1/256."
		   Well, at least that makes some sense.  Multiplying ENVX
		   by 255/256 every time DECAY is updated. */
		cnt-=ENVCNT[((adsr1>>3)&0xE)+0x10];
		if(cnt<=0)
		{
			cnt=CNT_INIT;
			envx-=((envx-1)>>8)+1;
			voice_state[v].envx=envx;
		}
		if(envx<=0x100*(SL(v)+1))
			voice_state[v].envstate=SUSTAIN;
#ifdef DBG_ENV
fprintf(stderr,"ENV voice %d: envx=%03X, state=DECAY\n",v,envx);
#endif
		break;
	case SUSTAIN:
		/* Docs: "SR [is multiplied] by the fixed value 1-1/256."
		   Multiplying ENVX by 255/256 every time SUSTAIN is
		   updated. */
#ifdef DBG_ENV
if(ENVCNT[SR(v)]==0)
 fprintf(stderr,"ENV voice %d: envx=%03X, state=SUSTAIN, zero rate\n",v,envx);
#endif
		cnt-=ENVCNT[SR(v)];
		if(cnt>0)
			break;
		cnt=CNT_INIT;
		envx-=((envx-1)>>8)+1;
#ifdef DBG_ENV
fprintf(stderr,"ENV voice %d: envx=%03X, state=SUSTAIN\n",v,envx);
#endif
		voice_state[v].envx=envx;
		/* Note: no way out of this state except by explicit KEY OFF
		   (or switch to GAIN). */
		break;
	case RELEASE:	/* Handled earlier to prevent GAIN mode from stopping
			   KEY OFF events */
		break;
	}
	else
	{	/* GAIN mode is set */
		/* Note: if the game switches between ADSR and GAIN modes
		   partway through, should the count be reset, or should it
		   continue from where it was?  Does the DSP actually watch
		   for that bit to change, or does it just go along with
		   whatever it sees when it performs the update?  I'm going
		   to assume the latter and not update the count, unless I
		   see a game that obviously wants the other behavior.  The
		   effect would be pretty subtle, in any case. */
		t=DSPregs[(v<<4)+7];
		if(t<0x80)
		{
			envx=voice_state[v].envx=t<<4;
#ifdef DBG_ENV
fprintf(stderr,"ENV voice %d: envx=%03X, state=DIRECT\n",v,envx);
#endif
		}
		else switch(t>>5)
		{
		case 4:	/* Docs: "Decrease (linear): Subtraction of the
			   fixed value 1/64." */
			cnt-=ENVCNT[t&0x1F];
			if(cnt>0)
				break;
			cnt=CNT_INIT;
			envx-=0x020;	/* 0x020 / 0x800 = 1/64th */
			if(envx<0)
				envx=0;
#ifdef DBG_ENV
fprintf(stderr,"ENV voice %d: envx=%03X, state=DECREASE\n",v,envx);
#endif
			voice_state[v].envx=envx;
			break;
		case 5: /* Docs: "Drecrease <sic> (exponential):
			   Multiplication by the fixed value 1-1/256." */
			cnt-=ENVCNT[t&0x1F];
			if(cnt>0)
				break;
			cnt=CNT_INIT;
			envx-=((envx-1)>>8)+1;
#ifdef DBG_ENV
fprintf(stderr,"ENV voice %d: envx=%03X, state=EXP\n",v,envx);
#endif
			voice_state[v].envx=envx;
			break;
		case 6: /* Docs: "Increase (linear): Addition of the fixed
			   value 1/64." */
			cnt-=ENVCNT[t&0x1F];
			if(cnt>0)
				break;
			cnt=CNT_INIT;
			envx+=0x020;	/* 0x020 / 0x800 = 1/64th */
			if(envx>0x7FF)
				envx=0x7FF;
#ifdef DBG_ENV
fprintf(stderr,"ENV voice %d: envx=%03X, state=INCREASE\n",v,envx);
#endif
			voice_state[v].envx=envx;
			break;
		case 7: /* Docs: "Increase (bent line): Addition of the
			   constant 1/64 up to .75 of the constaint <sic>
			   1/256 from .75 to 1." */
			cnt-=ENVCNT[t&0x1F];
			if(cnt>0)
				break;
			cnt=CNT_INIT;
			if(envx<0x600)		/* 0x600 / 0x800 = .75 */
				envx+=0x020;	/* 0x020 / 0x800 = 1/64 */
			else
				envx+=0x008;	/* 0x008 / 0x800 = 1/256 */
			if(envx>0x7FF)
				envx=0x7FF;
#ifdef DBG_ENV
fprintf(stderr,"ENV voice %d: envx=%03X, state=INCREASE\n",v,envx);
#endif
			voice_state[v].envx=envx;
			break;
		}

	}
	voice_state[v].envcnt=cnt;
	DSPregs[(v<<4)+8]=envx>>4;
	return envx;
}

/**** Shared functions (for internal library use only) ****/

void DSP_Update(short *sound_ptr)
{
	int v,V,m,envx,outl,outr,echol,echor,vl,vr;
#ifndef NO_ECHO
	int echo_base;
#endif
	signed long outx;	/* explicit type because it matters */
	struct voice_state *vp;
	struct src_dir *sd=(struct src_dir *)&SPC_RAM[(int)DSPregs[0x5D]<<8];
	
	/* Check for reset */
	if(DSPregs[0x6C]&0x80)
		DSP_Reset();
	/* Here we check for keys on/off.  Docs say that successive writes
	   to KON/KOF must be separated by at least 2 Ts periods or risk
	   being neglected.  Therefore DSP only looks at these during an
	   update, and not at the time of the write.  Only need to do this
	   once however, since the regs haven't changed over the whole
	   period we need to catch up with. */
#ifdef DBG_KEY
	DSPregs[0x4C]&=mask;
#endif
	DSPregs[0x7C]&=~DSPregs[0x4C];	/* Keying on a voice resets that bit
					   in ENDX. */
	/* Question: what is the expected behavior when pitch
	   modulation is enabled on voice 0?  Jurassic Park 2 does
	   this.  For now, using outx of zero for first voice. */
	outx=0;
	if(DSPregs[0x3D])
	{	/* Same table for noise and envelope, yay! */
		noise_cnt-=ENVCNT[DSPregs[0x6C]&0x1F];
		if(noise_cnt<=0)
		{
			noise_cnt=CNT_INIT;
			noise_lev=(rand()&0xFFFF)-0x8000;
		}
	}
	outl=outr=echol=echor=0;
	for(v=0,m=1,V=0;v<8;v++,V+=16,m<<=1)
	{
		vp=&voice_state[v];
		if(vp->on_cnt&&(--vp->on_cnt==0))
		{	/* voice was keyed on */
			keys|=m;
			keyed_on|=m;
			vl=DSPregs[(v<<4)+4];
			vp->samp_id=*(unsigned long *)&sd[vl];
			vp->mem_ptr=sd[vl].vptr;
#ifdef DBG_KEY
fprintf(stderr,"Keying on voice %d, samp=0x%04X\n",v,vp->mem_ptr);
#endif
			vp->header_cnt=vp->half=vp->envx=vp->end=
			  vp->sampptr=0;
			vp->mixfrac=3*4096;
			/* NOTE: Real SNES does *not* appear to initialize
			   the envelope counter to anything in particular.
			   The first cycle always seems to come at a random
			   time sooner than expected; as yet, I have been
			   unable to find any pattern.  I doubt it will
			   matter though, so we'll go ahead and do the full
			   time for now. */
			vp->envcnt=CNT_INIT;
			vp->envstate=ATTACK;
		}
		if(DSPregs[0x4C]&m&~DSPregs[0x5C])
		{	/* Voice doesn't come on if key off is set */
			DSPregs[0x4C]&=~m;
			vp->on_cnt=8;
#ifdef DBG_KEY
fprintf(stderr,"Key on set for voice %d\n",v);
#endif
		}
		if(keys&DSPregs[0x5C]&m)
		{	/* voice was keyed off */
#ifdef DBG_KEY
fprintf(stderr,"Keying off voice %d\n",v);
#endif
			vp->envstate=RELEASE;
			vp->on_cnt=0;
		}
		if(!(keys&m&mask)||((envx=AdvanceEnvelope(v))<0))
		{
			DSPregs[V+8]=DSPregs[V+9]=outx=0;
			continue;
		}
		vp->pitch=LEtoME16(
		  *((unsigned short *)&DSPregs[V+2]))&0x3FFF;
#ifndef NO_PMOD
		/* Pitch mod uses OUTX from last voice for this one.
		   Luckily we haven't modified OUTX since it was used
		   for last voice. */
		if(DSPregs[0x2D]&m)
		{
#ifdef DBG_PMOD
fprintf(stderr,"Pitch Modulating voice %d, outx=%ld, old pitch=%d, ",v,outx,vp->pitch);
#endif
			vp->pitch=(vp->pitch*(outx+32768))>>15;
#ifdef DBG_PMOD
fprintf(stderr,"new pitch=%d\n",vp->pitch);
#endif
		}
#endif
		for(;vp->mixfrac>=0;vp->mixfrac-=4096)
		{
			/* This part performs the BRR decode
			   'on-the-fly'.  This is more correct than
			   the old way, which could be fooled if the
			   data and/or the loop point changed while
			   the sample was playing, or if the BRR
			   decode didn't produce the same result every
			   loop because of the filters.  The event
			   interface still has no chance of keeping
			   up with those kinds of tricks, though. */
			if(!vp->header_cnt)
			{
				if(vp->end&1)
				{
    				/* Docs say ENDX bit is set
					   when decode of block with
					   source end flag set is
					   done.  Does this apply to
					   looping samples?  Some
					   info I've seen suggests
					   yes. */
					DSPregs[0x7C]|=m;
					if(vp->end&2)
					{
						vp->mem_ptr=LEtoME16(
						 sd[DSPregs[V+4]]
						  .lptr);
					}
					else
					{
#ifdef DBG_KEY
fprintf(stderr,"BRR decode end, voice %d\n",v);
#endif
						keys&=~m;
						DSPregs[V+8]=
						  vp->envx=0;
						while(vp->mixfrac>=0)
						{
						 vp->sampbuf[
						  vp->sampptr]=
						  outx=0;
						 vp->sampptr=
						  (vp->sampptr+1)&3;
						 vp->mixfrac-=4096;
						}
						break;
					}
				}
				vp->header_cnt=8;
				vl=(unsigned char)
				  SPC_RAM[vp->mem_ptr++];
				vp->range=vl>>4;
				vp->end=vl&3;
				vp->filter=(vl&12)>>2;
#ifdef DBG_BRR
fprintf(stderr,"V%d: header read, range=%d, end=%d, filter=%d\n",v,vp->range,vp->end,vp->filter);
#endif
			}
			if(vp->half==0)
			{
				vp->half=1;
				outx=((signed char)
				  SPC_RAM[vp->mem_ptr])>>4;
			}
			else
			{
				vp->half=0;
				/* Funkiness to get 4-bit signed to
				   carry through */
				outx=(signed char)
				 (SPC_RAM[vp->mem_ptr++]<<4);
				outx>>=4;
				vp->header_cnt--;
			}
#ifdef DBG_BRR
fprintf(stderr,"V%d: nybble=%X, ptr=%04X, smp1=%d, smp2=%d\n",v,outx&0xF,vp->mem_ptr,vp->smp1,vp->smp2);
#endif
			/* For invalid ranges (D,E,F): if the nybble is
			   negative, the result is F000.  If positive, 0000.
			   Nothing else like previous range, etc seems to
			   have any effect.  If range is valid, do the shift
			   normally.  Note these are both shifted right once
			   to do the filters properly, but the output will
			   be shifted back again at the end. */
			if(vp->range<=0xC)
				outx=(outx<<vp->range)>>1;
			else
			{
				outx&=~0x7FF;
#ifdef DBG_BRR
fprintf(stderr,"V%d: invalid range! (%X)\n",v,vp->range);
#endif
			}
#ifdef DBG_BRR
fprintf(stderr,"V%d: shifted delta=%04X\n",v,(unsigned short)outx);
#endif
			switch(vp->filter)
			{
			case 0:
				break;
			case 1:
				outx+=vp->smp1>>1;
				outx+=(-vp->smp1)>>5;
				break;
			case 2:
				outx+=vp->smp1;
				outx+=(-(vp->smp1+
				         (vp->smp1>>1)))>>5;
				outx-=vp->smp2>>1;
				outx+=vp->smp2>>5;
				break;
			case 3:
				outx+=vp->smp1;
				outx+=(-(vp->smp1+
				         (vp->smp1<<2)+
				         (vp->smp1<<3)))>>7;
				outx-=vp->smp2>>1;
				outx+=(vp->smp2+
				       (vp->smp2>>1))>>4;
				break;
			}
			if(outx<(signed short)0x8000)
				outx=(signed short)0x8000;
			else if(outx>(signed short)0x7FFF)
				outx=(signed short)0x7FFF;
#ifdef DBG_BRR
fprintf(stderr,"V%d: filter + delta=%04X\n",v,(unsigned short)outx);
#endif
			vp->smp2=(signed short)vp->smp1;
			vp->smp1=vp->sampbuf[vp->sampptr]=
			 (signed short)(outx<<1);
#ifdef DBG_BRR
fprintf(stderr,"V%d: final output: %04X\n",v,vp->sampbuf[vp->sampptr]);
#endif
			vp->sampptr=(vp->sampptr+1)&3;
		}
		if(DSPregs[0x3D]&m)
		{
#ifdef DBG_PMOD
fprintf(stderr,"Noise enabled, voice %d\n",v);
#endif
			outx=noise_lev;
		}
		else
		{	/* Perform 4-Point Gaussian interpolation.
			   Take an approximation of a Gaussian
			   bell-curve, and move it through the
			   sample data at a rate determined by the
			   pitch.  The sample output at any given
			   time is the sum of the products of each
			   input sample point with the value of the
			   bell-curve corresponding to that point. */
			vl=vp->mixfrac>>4;
			vr=(G4[-vl]*vp->sampbuf[vp->sampptr])&~2047;
			vr+=(G3[-vl]*vp->sampbuf[(vp->sampptr+1)&3])&~2047;
			vr+=(G2[vl]*vp->sampbuf[(vp->sampptr+2)&3])&~2047;
			vr+=(G1[vl]*vp->sampbuf[(vp->sampptr+3)&3])&~2047;
			outx=(signed short)(vr>>11)&~1;
#ifdef DBG_INTRP
fprintf(stderr,"V%d: mixfrac=%d: [%d]*%d + [%d]*%d + [%d]*%d + [%d]*%d = %d\n",v,vl,G1[vl],vp->sampbuf[(vp->sampptr+3)&3],G2[vl],vp->sampbuf[(vp->sampptr+2)&3],G3[-vl],vp->sampbuf[(vp->sampptr+1)&3],G4[-vl],vp->sampbuf[vp->sampptr],outx);
#endif
		}
		
		/* Advance the sample position for next update. */
		vp->mixfrac+=vp->pitch;
		
		outx=((outx*envx)>>11)&~1;
		DSPregs[V+9]=outx>>8;

		vl=(((int)(signed char)DSPregs[V])*outx)>>7;
		vr=(((int)(signed char)DSPregs[V+1])*outx)>>7;
		outl+=vl;
		outr+=vr;
		if(DSPregs[0x4D]&m)
		{
			echol+=vl;
			echor+=vr;
		}
	}
	outl=(outl*(signed char)DSPregs[0x0C])>>7;
	outr=(outr*(signed char)DSPregs[0x1C])>>7;
#ifndef NO_ECHO
	/* Perform echo.  First, read mem at current location, and
	   put those samples into the FIR filter queue. */
#ifdef DBG_ECHO
fprintf(stderr,"Echo delay=%dms, feedback=%d%%\n",DSPregs[0x7D]*16,((signed char)DSPregs[0x0D]*100)/0x7F);
#endif
	echo_base=((DSPregs[0x6D]<<8)+echo_ptr)&0xFFFF;
	FIRlbuf[FIRptr]=LEtoME16(
	 *(signed short *)&SPC_RAM[echo_base]);
	FIRrbuf[FIRptr]=LEtoME16(
	 *(signed short *)&SPC_RAM[echo_base+sizeof(short)]);

	/* Now, evaluate the FIR filter, and add the results
	   into the final output. */
	vl=FIRlbuf[FIRptr]*(signed char)DSPregs[0x7F];
	vr=FIRrbuf[FIRptr]*(signed char)DSPregs[0x7F];
	FIRptr=(FIRptr+1)&7;
	vl+=FIRlbuf[FIRptr]*(signed char)DSPregs[0x6F];
	vr+=FIRrbuf[FIRptr]*(signed char)DSPregs[0x6F];
	FIRptr=(FIRptr+1)&7;
	vl+=FIRlbuf[FIRptr]*(signed char)DSPregs[0x5F];
	vr+=FIRrbuf[FIRptr]*(signed char)DSPregs[0x5F];
	FIRptr=(FIRptr+1)&7;
	vl+=FIRlbuf[FIRptr]*(signed char)DSPregs[0x4F];
	vr+=FIRrbuf[FIRptr]*(signed char)DSPregs[0x4F];
	FIRptr=(FIRptr+1)&7;
	vl+=FIRlbuf[FIRptr]*(signed char)DSPregs[0x3F];
	vr+=FIRrbuf[FIRptr]*(signed char)DSPregs[0x3F];
	FIRptr=(FIRptr+1)&7;
	vl+=FIRlbuf[FIRptr]*(signed char)DSPregs[0x2F];
	vr+=FIRrbuf[FIRptr]*(signed char)DSPregs[0x2F];
	FIRptr=(FIRptr+1)&7;
	vl+=FIRlbuf[FIRptr]*(signed char)DSPregs[0x1F];
	vr+=FIRrbuf[FIRptr]*(signed char)DSPregs[0x1F];
	FIRptr=(FIRptr+1)&7;
	vl+=FIRlbuf[FIRptr]*(signed char)DSPregs[0x0F];
	vr+=FIRrbuf[FIRptr]*(signed char)DSPregs[0x0F];
	/* FIRptr is left in the position of the oldest
	   sample, the one that will be replaced next
	   update. */
	outl+=vl*(signed char)DSPregs[0x2C]>>14;
	outr+=vr*(signed char)DSPregs[0x3C]>>14;

	if(!(DSPregs[0x6C]&0x20))
	{	/* Add the echo feedback back into the original
		   result, and save that into memory for use later. */
		echol+=vl*(signed char)DSPregs[0x0D]>>14;
		if(echol>32767)
			echol=32767;
		else if(echol<-32768)
			echol=-32768;
		echor+=vr*(signed char)DSPregs[0x0D]>>14;
		if(echor>32767)
			echor=32767;
		else if(echor<-32768)
			echor=-32768;
#ifdef DBG_ECHO
fprintf(stderr,"Echo: Writing %04X,%04X at location %04X\n",(unsigned short)echol,(unsigned short)echor,echo_base);
#endif
		*(signed short *)&SPC_RAM[echo_base]=MEtoLE16(echol);
		*(signed short *)&SPC_RAM[echo_base+sizeof(short)]=
		  MEtoLE16(echor);
	}
	echo_ptr+=2*sizeof(short);
	if(echo_ptr>=((DSPregs[0x7D]&0xF)<<11))
		echo_ptr=0;
#endif
	if(sound_ptr)
	{
		if(DSPregs[0x6C]&0x40)
		{	/* MUTE */
#ifdef DEBUG
fprintf(stderr,"MUTED!\n");
#endif
			*sound_ptr=0;
			sound_ptr++;
			*sound_ptr=0;
			sound_ptr++;
		}
		else
		{
			if(outl>32767)
				*sound_ptr=32767;
			else if(outl<-32768)
				*sound_ptr=-32768;
			else
				*sound_ptr=outl;
			sound_ptr++;
			if(outr>32767)
				*sound_ptr=32767;
			else if(outr<-32768)
				*sound_ptr=-32768;
			else
				*sound_ptr=outr;
			sound_ptr++;
		}
	}
/*	DSPregs[0x4C]=0;*/
}

void DSP_Reset(void)
{
	int i;
#ifdef DEBUG
fprintf(stderr,"DSP_Reset\n");
#endif
	for(i=0;i<8;i++)
#ifndef NO_ECHO
		FIRlbuf[i]=FIRrbuf[i]=
#endif
		 voice_state[i].on_cnt=0;
#ifndef NO_ECHO
	FIRptr=echo_ptr=0;
#endif
	keys=keyed_on=noise_cnt=0;
	DSPregs[0x6C]|=0xE0;
	DSPregs[0x4C]=DSPregs[0x5C]=0;
}