otomatalabs/furnace
7
0
Fork 0
Code Issues Pull requests Actions Packages Projects Releases Wiki Activity
furnace/src/engine/platform/sound/su.cpp
tildearrow 4f5c6cbbb5 SoundUnit: emulation changes 
no longer uses int for the filter stages, instead using short
this makes a 1982 design cheaper and more viable
2024-09-09 19:28:16 -05:00

415 lines
12 KiB
C++
Raw Blame History

/* su.cpp/su.h - Sound Unit emulator
* Copyright (C) 2015-2023 tildearrow
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#define _USE_MATH_DEFINES
#include "su.h"
#include <string.h>
#define minval(a,b) (((a)<(b))?(a):(b))
#define maxval(a,b) (((a)>(b))?(a):(b))
#define FILVOL chan[4].special1C
#define ILCTRL chan[4].special1D
#define ILSIZE chan[5].special1C
#define FIL1 chan[5].special1D
#define IL1 chan[6].special1C
#define IL2 chan[6].special1D
#define IL0 chan[7].special1C
#define MVOL chan[7].special1D
void SoundUnit::NextSample(short* l, short* r) {
// run channels
for (int i=0; i<8; i++) {
if (chan[i].vol==0 && !(chan[i].flags1&32)) {
fns[i]=0;
continue;
}
if (chan[i].flags0&8) {
ns[i]=pcm[chan[i].pcmpos];
} else switch (chan[i].flags0&7) {
case 0:
ns[i]=(((cycle[i]>>15)&127)>chan[i].duty)*127;
break;
case 1:
ns[i]=cycle[i]>>14;
break;
case 2:
ns[i]=SCsine[(cycle[i]>>14)&255];
break;
case 3:
ns[i]=SCtriangle[(cycle[i]>>14)&255];
break;
case 4: case 5:
ns[i]=(lfsr[i]&1)*127;
break;
case 6:
ns[i]=((((cycle[i]>>15)&127)>chan[i].duty)*127)^(short)SCsine[(cycle[i]>>14)&255];
break;
case 7:
ns[i]=((((cycle[i]>>15)&127)>chan[i].duty)*127)^(short)SCtriangle[(cycle[i]>>14)&255];
break;
}
// ring mod
if (chan[i].flags0&16) {
ns[i]=(ns[i]*ns[(i+1)&7])>>7;
}
// PCM
if (chan[i].flags0&8) {
if (chan[i].freq>0x8000) {
pcmdec[i]+=0x8000;
} else {
pcmdec[i]+=chan[i].freq;
}
if (pcmdec[i]>=32768) {
pcmdec[i]-=32768;
if (chan[i].pcmpos<chan[i].pcmbnd) {
chan[i].pcmpos++;
if (chan[i].pcmpos==chan[i].pcmbnd) {
if (chan[i].flags1&4) {
chan[i].pcmpos=chan[i].pcmrst;
}
}
chan[i].pcmpos&=(pcmSize-1);
} else if (chan[i].flags1&4) {
chan[i].pcmpos=chan[i].pcmrst;
}
}
} else {
ocycle[i]=cycle[i];
if ((chan[i].flags0&7)==5) {
switch ((chan[i].duty>>4)&3) {
case 0:
cycle[i]+=chan[i].freq*1-(chan[i].freq>>3);
break;
case 1:
cycle[i]+=chan[i].freq*2-(chan[i].freq>>3);
break;
case 2:
cycle[i]+=chan[i].freq*4-(chan[i].freq>>3);
break;
case 3:
cycle[i]+=chan[i].freq*8-(chan[i].freq>>3);
break;
}
} else {
cycle[i]+=chan[i].freq;
}
if ((cycle[i]&0xf80000)!=(ocycle[i]&0xf80000)) {
if ((chan[i].flags0&7)==4) {
lfsr[i]=(lfsr[i]>>1|(((lfsr[i]) ^ (lfsr[i] >> 2) ^ (lfsr[i] >> 3) ^ (lfsr[i] >> 5) ) & 1)<<31);
} else {
switch ((chan[i].duty>>4)&3) {
case 0:
lfsr[i]=(lfsr[i]>>1|(((lfsr[i] >> 3) ^ (lfsr[i] >> 4) ) & 1)<<5);
break;
case 1:
lfsr[i]=(lfsr[i]>>1|(((lfsr[i] >> 2) ^ (lfsr[i] >> 3) ) & 1)<<5);
break;
case 2:
lfsr[i]=(lfsr[i]>>1|(((lfsr[i]) ^ (lfsr[i] >> 2) ^ (lfsr[i] >> 3) ) & 1)<<5);
break;
case 3:
lfsr[i]=(lfsr[i]>>1|(((lfsr[i]) ^ (lfsr[i] >> 2) ^ (lfsr[i] >> 3) ^ (lfsr[i] >> 5) ) & 1)<<5);
break;
}
if ((lfsr[i]&63)==0) {
lfsr[i]=0xaaaa;
}
}
}
if (chan[i].flags1&8) {
if (--rcycle[i]<=0) {
cycle[i]=0;
rcycle[i]=chan[i].restimer;
lfsr[i]=0xaaaa;
}
}
}
fns[i]=ns[i]*chan[i].vol;
if (!(chan[i].flags0&8)) fns[i]>>=1;
if ((chan[i].flags0&0xe0)!=0) {
int ff=chan[i].cutoff;
nslow[i]=nslow[i]+(((ff)*nsband[i])>>16);
nshigh[i]=fns[i]-nslow[i]-(((256-chan[i].reson)*nsband[i])>>8);
nsband[i]=(((ff)*nshigh[i])>>16)+nsband[i];
fns[i]=(((chan[i].flags0&32)?(nslow[i]):(0))+((chan[i].flags0&64)?(nshigh[i]):(0))+((chan[i].flags0&128)?(nsband[i]):(0)));
}
nsL[i]=(fns[i]*SCpantabL[(unsigned char)chan[i].pan])>>8;
nsR[i]=(fns[i]*SCpantabR[(unsigned char)chan[i].pan])>>8;
oldfreq[i]=chan[i].freq;
if (chan[i].flags1&32) {
if (--swvolt[i]<=0) {
swvolt[i]=chan[i].swvol.speed;
if (chan[i].swvol.amt&32) {
chan[i].vol+=chan[i].swvol.amt&31;
if (chan[i].vol>chan[i].swvol.bound && !(chan[i].swvol.amt&64)) {
chan[i].vol=chan[i].swvol.bound;
}
if (chan[i].vol&0x80) {
if (chan[i].swvol.amt&64) {
if (chan[i].swvol.amt&128) {
chan[i].swvol.amt^=32;
chan[i].vol=0xff-chan[i].vol;
} else {
chan[i].vol&=~0x80;
}
} else {
chan[i].vol=0x7f;
}
}
} else {
chan[i].vol-=chan[i].swvol.amt&31;
if (chan[i].vol&0x80) {
if (chan[i].swvol.amt&64) {
if (chan[i].swvol.amt&128) {
chan[i].swvol.amt^=32;
chan[i].vol=-chan[i].vol;
} else {
chan[i].vol&=~0x80;
}
} else {
chan[i].vol=0x0;
}
}
if (chan[i].vol<chan[i].swvol.bound && !(chan[i].swvol.amt&64)) {
chan[i].vol=chan[i].swvol.bound;
}
}
}
}
if (chan[i].flags1&16) {
if (--swfreqt[i]<=0) {
swfreqt[i]=chan[i].swfreq.speed;
if (chan[i].swfreq.amt&128) {
if (chan[i].freq>(0xffff-(chan[i].swfreq.amt&127))) {
chan[i].freq=0xffff;
} else {
chan[i].freq=(chan[i].freq*(0x80+(chan[i].swfreq.amt&127)))>>7;
if ((chan[i].freq>>8)>chan[i].swfreq.bound) {
chan[i].freq=chan[i].swfreq.bound<<8;
}
}
} else {
if (chan[i].freq<(chan[i].swfreq.amt&127)) {
chan[i].freq=0;
} else {
chan[i].freq=(chan[i].freq*(0xff-(chan[i].swfreq.amt&127)))>>8;
if ((chan[i].freq>>8)<chan[i].swfreq.bound) {
chan[i].freq=chan[i].swfreq.bound<<8;
}
}
}
}
}
if (chan[i].flags1&64) {
if (--swcutt[i]<=0) {
swcutt[i]=chan[i].swcut.speed;
if (chan[i].swcut.amt&128) {
if (chan[i].cutoff>(0xffff-(chan[i].swcut.amt&127))) {
chan[i].cutoff=0xffff;
} else {
chan[i].cutoff+=chan[i].swcut.amt&127;
if ((chan[i].cutoff>>8)>chan[i].swcut.bound) {
chan[i].cutoff=chan[i].swcut.bound<<8;
}
}
} else {
if (chan[i].cutoff<(chan[i].swcut.amt&127)) {
chan[i].cutoff=0;
} else {
chan[i].cutoff=((2048-(unsigned int)(chan[i].swcut.amt&127))*(unsigned int)chan[i].cutoff)>>11;
if ((chan[i].cutoff>>8)<chan[i].swcut.bound) {
chan[i].cutoff=chan[i].swcut.bound<<8;
}
}
}
}
}
if (chan[i].flags1&1) {
cycle[i]=0;
rcycle[i]=chan[i].restimer;
ocycle[i]=0;
chan[i].flags1&=~1;
}
if (muted[i]) {
nsL[i]=0;
nsR[i]=0;
}
}
// mix
if (dsOut) {
tnsL=nsL[dsChannel]<<3;
tnsR=nsR[dsChannel]<<3;
dsChannel=(dsChannel+1)&7;
} else {
tnsL=(nsL[0]+nsL[1]+nsL[2]+nsL[3]+nsL[4]+nsL[5]+nsL[6]+nsL[7]);
tnsR=(nsR[0]+nsR[1]+nsR[2]+nsR[3]+nsR[4]+nsR[5]+nsR[6]+nsR[7]);
IL1=minval(32767,maxval(-32767,tnsL))>>8;
IL2=minval(32767,maxval(-32767,tnsR))>>8;
}
// write input lines to sample memory
if (ILSIZE&64) {
if (++ilBufPeriod>=((1+(FIL1>>4))<<2)) {
ilBufPeriod=0;
unsigned short ilLowerBound=pcmSize-((1+(ILSIZE&63))<<7);
short next;
if (ilBufPos<ilLowerBound) ilBufPos=ilLowerBound;
switch (ILCTRL&3) {
case 0:
ilFeedback0=ilFeedback1=pcm[ilBufPos];
next=((signed char)IL0)+((pcm[ilBufPos]*(FIL1&15))>>4);
if (next<-128) next=-128;
if (next>127) next=127;
pcm[ilBufPos]=next;
if (++ilBufPos>=pcmSize) ilBufPos=ilLowerBound;
break;
case 1:
ilFeedback0=ilFeedback1=pcm[ilBufPos];
next=((signed char)IL1)+((pcm[ilBufPos]*(FIL1&15))>>4);
if (next<-128) next=-128;
if (next>127) next=127;
pcm[ilBufPos]=next;
if (++ilBufPos>=pcmSize) ilBufPos=ilLowerBound;
break;
case 2:
ilFeedback0=ilFeedback1=pcm[ilBufPos];
next=((signed char)IL2)+((pcm[ilBufPos]*(FIL1&15))>>4);
if (next<-128) next=-128;
if (next>127) next=127;
pcm[ilBufPos]=next;
if (++ilBufPos>=pcmSize) ilBufPos=ilLowerBound;
break;
case 3:
ilFeedback0=pcm[ilBufPos];
next=((signed char)IL1)+((pcm[ilBufPos]*(FIL1&15))>>4);
if (next<-128) next=-128;
if (next>127) next=127;
pcm[ilBufPos]=next;
if (++ilBufPos>=pcmSize) ilBufPos=ilLowerBound;
ilFeedback1=pcm[ilBufPos];
next=((signed char)IL2)+((pcm[ilBufPos]*(FIL1&15))>>4);
if (next<-128) next=-128;
if (next>127) next=127;
pcm[ilBufPos]=next;
if (++ilBufPos>=pcmSize) ilBufPos=ilLowerBound;
break;
}
}
if (ILCTRL&4) {
if (ILSIZE&128) {
tnsL+=ilFeedback1*(signed char)FILVOL;
tnsR+=ilFeedback0*(signed char)FILVOL;
} else {
tnsL+=ilFeedback0*(signed char)FILVOL;
tnsR+=ilFeedback1*(signed char)FILVOL;
}
}
}
if (dsOut) {
*l=minval(32767,maxval(-32767,tnsL))&0xff00;
*r=minval(32767,maxval(-32767,tnsR))&0xff00;
} else {
*l=minval(32767,maxval(-32767,tnsL));
*r=minval(32767,maxval(-32767,tnsR));
}
}
void SoundUnit::Init(int sampleMemSize, bool dsOutMode) {
pcmSize=sampleMemSize;
dsOut=dsOutMode;
Reset();
memset(pcm,0,pcmSize);
for (int i=0; i<256; i++) {
SCsine[i]=sin((i/128.0f)*M_PI)*127;
SCtriangle[i]=(i>127)?(255-i):(i);
SCpantabL[i]=127;
SCpantabR[i]=127;
}
for (int i=0; i<128; i++) {
SCpantabL[i]=127-i;
SCpantabR[128+i]=i-1;
}
SCpantabR[128]=0;
}
void SoundUnit::Reset() {
for (int i=0; i<8; i++) {
ocycle[i]=0;
cycle[i]=0;
rcycle[i]=0;
resetfreq[i]=0;
voldcycles[i]=0;
volicycles[i]=0;
fscycles[i]=0;
sweep[i]=0;
ns[i]=0;
fns[i]=0;
nsL[i]=0;
nsR[i]=0;
nslow[i]=0;
nshigh[i]=0;
nsband[i]=0;
swvolt[i]=1;
swfreqt[i]=1;
swcutt[i]=1;
lfsr[i]=0xaaaa;
oldfreq[i]=0;
pcmdec[i]=0;
}
dsChannel=0;
tnsL=0;
tnsR=0;
ilBufPos=0;
ilBufPeriod=0;
ilFeedback0=0;
ilFeedback1=0;
memset(chan,0,sizeof(SUChannel)*8);
}
#ifdef TA_BIG_ENDIAN
const unsigned char suBERemap[32]={
0x01, 0x00, 0x02, 0x03, 0x04, 0x05, 0x07, 0x06, 0x08, 0x09, 0x0b, 0x0a, 0x0d, 0x0c, 0x0f, 0x0e,
0x11, 0x10, 0x12, 0x13, 0x15, 0x14, 0x16, 0x17, 0x19, 0x18, 0x1a, 0x1b, 0x1c, 0x1d, 0x1f, 0x1e
};
#endif
void SoundUnit::Write(unsigned char addr, unsigned char data) {
#ifdef TA_BIG_ENDIAN
// remap
addr=(addr&0xe0)|(suBERemap[addr&0x1f]);
#endif
((unsigned char*)chan)[addr]=data;
}
SoundUnit::SoundUnit() {
Init(65536); // default
for (int i=0; i<8; i++) {
muted[i]=false;
}
}
Reference in a new issue View git blame Copy permalink