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games/gb: improve sound emulation by modelling analog behaviour

front
aiju 2015-04-12 14:55:25 +02:00
parent d009b0013d
commit e8221d07d8
4 changed files with 187 additions and 146 deletions
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314
sys/src/games/gb/apu.c
View File

@ -4,8 +4,10 @@
#include "dat.h"
#include "fns.h"
double TAU = 25000;
Event evsamp;
extern Event evenv, evwave;
extern Event evenv;
s16int sbuf[2*4000], *sbufp;
enum {
Freq = 44100,
@ -18,29 +20,31 @@ u8int sweepen, sweepcalc, sweepctr;
u16int sweepfreq;
typedef struct chan chan;
struct chan {
u8int n, ectr;
u16int len;
u8int *env, *freq;
u16int fctr, fthr;
u32int finc;
u8int vol;
int per;
u16int len;
u8int n, ectr;
u8int vol, ctr, samp;
};
u8int wpos;
u16int lfsr;
u8int apustatus;
ulong waveclock;
u8int wavebuf;
double samp[2];
chan sndch[4] = {
{
.n = 0,
.env = reg + NR12,
.freq = reg + NR14,
.per = 8 * 2048,
},
{
.n = 1,
.env = reg + NR22,
.freq = reg + NR24,
.per = 8 * 2048,
},
{
.n = 2,
@ -49,114 +53,171 @@ chan sndch[4] = {
.n = 3,
.env = reg + NR42,
.freq = reg + NR44,
.per = 32
}
};
Event chev[4] = {
{.aux = &sndch[0]},
{.aux = &sndch[1]},
{.aux = &sndch[2]},
{.aux = &sndch[3]}
};
Var apuvars[] = {
VAR(apustatus), VAR(envmod), VAR(sweepen), VAR(sweepcalc),
VAR(sweepctr), VAR(sweepfreq), VAR(wpos), VAR(lfsr), VAR(waveclock), VAR(wavebuf),
VAR(sndch[0].ectr), VAR(sndch[0].len), VAR(sndch[0].fctr), VAR(sndch[0].fthr), VAR(sndch[0].finc), VAR(sndch[0].vol),
VAR(sndch[1].ectr), VAR(sndch[1].len), VAR(sndch[1].fctr), VAR(sndch[1].fthr), VAR(sndch[1].finc), VAR(sndch[1].vol),
VAR(sndch[2].ectr), VAR(sndch[2].len), VAR(sndch[2].fctr), VAR(sndch[2].fthr), VAR(sndch[2].finc), VAR(sndch[2].vol),
VAR(sndch[3].ectr), VAR(sndch[3].len), VAR(sndch[3].fctr), VAR(sndch[3].fthr), VAR(sndch[3].finc), VAR(sndch[3].vol),
VAR(sndch[0].ectr), VAR(sndch[0].len), VAR(sndch[0].per), VAR(sndch[0].ctr), VAR(sndch[0].vol), VAR(sndch[0].samp),
VAR(sndch[1].ectr), VAR(sndch[1].len), VAR(sndch[1].per), VAR(sndch[1].ctr), VAR(sndch[1].vol), VAR(sndch[1].samp),
VAR(sndch[2].ectr), VAR(sndch[2].len), VAR(sndch[2].per), VAR(sndch[2].vol), VAR(sndch[2].samp),
VAR(sndch[3].ectr), VAR(sndch[3].len), VAR(sndch[3].per), VAR(sndch[3].vol), VAR(sndch[3].samp),
{nil, 0, 0},
};
void
rate(int i, u16int v)
static void
rate(chan *c, u16int v)
{
switch(i){
switch(c->n){
case 0: case 1:
sndch[i].finc = 131072ULL * 65536 / (Freq * (2048 - (v & 0x7ff)));
c->per = 8 * (2048 - (v & 0x7ff));
break;
case 2:
sndch[2].finc = 4 * (2048 - (v & 0x7ff));
c->per = 4 * (2048 - (v & 0x7ff));
break;
case 3:
sndch[3].finc = 524288ULL * 65536 / Freq;
c->per = 32;
if((v & 7) != 0)
sndch[3].finc /= v & 7;
c->per *= v & 7;
else
sndch[3].finc <<= 1;
sndch[3].finc >>= (v >> 4 & 15) + 1;
c->per >>= 1;
c->per <<= (v >> 4 & 15);
}
}
void
env(chan *c)
static void
filter(int t)
{
if((envmod & 1) == 0 && c->len > 0 && (*c->freq & 1<<6) != 0)
if(--c->len == 0){
apustatus &= ~(1<<c->n);
c->vol = 0;
return;
static int ov0, ov1;
static u32int oclock;
double e;
u8int cntl, cnth;
int i, v;
e = exp((clock + t - oclock) * -(TAU / FREQ));
samp[0] = e * samp[0] + (1 - e) * ov0;
samp[1] = e * samp[1] + (1 - e) * ov1;
oclock = clock + t;
cntl = reg[NR50];
cnth = reg[NR51];
ov0 = 0;
ov1 = 0;
for(i = 0; i < 4; i++){
if(i == 2 ? ((reg[NR30] & 0x80) == 0) : ((*sndch[i].env & 0xf8) == 0))
continue;
v = sndch[i].samp * 2 - 15;
if((cnth & 1<<i) != 0)
ov0 += v;
if((cnth & 1<<4<<i) != 0)
ov1 += v;
}
ov0 *= 1 + (cntl & 7);
ov1 *= 1 + (cntl >> 4 & 7);
}
static void
chansamp(chan *c, int t)
{
u8int ov;
ov = c->samp;
switch(c->n){
case 0: case 1:
c->samp = c->vol;
switch(reg[NR21] >> 6){
case 0: if(c->ctr < 7) c->samp = 0; break;
case 1: if(c->ctr < 6) c->samp = 0; break;
case 2: if(c->ctr < 4) c->samp = 0; break;
case 3: if(c->ctr >= 6) c->samp = 0; break;
}
if((apustatus & 1<<c->n) == 0 || (envmod & 7) != 7 || c->ectr == 0 || --c->ectr != 0)
return;
c->ectr = *c->env & 7;
if((*c->env & 1<<3) != 0){
if(c->vol < 15)
c->vol++;
}else
if(c->vol > 0)
c->vol--;
break;
case 2:
if((apustatus & 1<<4) == 0){
c->samp = 0;
break;
}
c->samp = wavebuf;
if((wpos & 1) == 0)
c->samp >>= 4;
else
c->samp &= 0xf;
if((reg[NR32] & 3<<5) == 0)
c->samp = 0;
else
c->samp = c->samp >> (reg[NR32] >> 5 & 3) - 1;
break;
case 3:
c->samp = (lfsr & 1) != 0 ? 0 : c->vol;
}
if(ov != c->samp)
filter(t);
}
void
wavetick(void *)
chantick(void *vc)
{
addevent(&evwave, sndch[2].finc);
wpos = wpos + 1 & 31;
wavebuf = reg[WAVE + (wpos >> 1)];
waveclock = clock;
}
s8int
wavesamp(void)
{
u8int x;
if((apustatus & 1<<4) == 0)
return 0;
x = wavebuf;
if((wpos & 1) == 0)
x >>= 4;
else
x &= 0xf;
if((reg[NR32] & 3<<5) == 0)
x = 0;
else
x = x >> (reg[NR32] >> 5 & 3) - 1;
return x;
}
s8int
lfsrsamp(void)
{
int v;
chan *c;
u16int l;
sndch[3].fctr = v = sndch[3].fctr + sndch[3].finc;
for(;;){
c = vc;
switch(c->n){
case 0: case 1:
c->ctr = c->ctr - 1 & 7;
break;
case 2:
wpos = wpos + 1 & 31;
wavebuf = reg[WAVE + (wpos >> 1)];
waveclock = clock;
break;
case 3:
l = lfsr;
v -= 0x10000;
if(v < 0)
break;
lfsr >>= 1;
if(((l ^ lfsr) & 1) != 0)
if((reg[NR43] & 1<<3) != 0)
lfsr |= 0x40;
else
lfsr |= 0x4000;
break;
}
if((l & 1) != 0)
return 0;
else
return sndch[3].vol;
chansamp(c, chev[c->n].time);
addevent(&chev[c->n], c->per);
}
void
sweep(int wb)
static void
env(chan *c, int t)
{
if((envmod & 1) == 0 && c->len > 0 && (*c->freq & 1<<6) != 0)
if(--c->len == 0){
apustatus &= ~(1<<c->n);
c->vol = 0;
chansamp(c, t);
return;
}
if((apustatus & 1<<c->n) == 0 || (envmod & 7) != 7 || c->ectr == 0 || --c->ectr != 0)
return;
c->ectr = *c->env & 7;
if((*c->env & 1<<3) != 0){
if(c->vol < 15){
c->vol++;
chansamp(c, t);
}
}else
if(c->vol > 0){
c->vol--;
chansamp(c, t);
}
}
static void
sweep(int wb, int t)
{
u16int fr;
int d;
@ -171,14 +232,15 @@ sweep(int wb)
if(fr > 2047){
sndch[0].len = 0;
sndch[0].vol = 0;
chansamp(&sndch[0], t);
apustatus &= ~1;
sweepen = 0;
}else if(wb && (cnt & 7) != 0){
sweepfreq = fr;
reg[NR13] = fr;
reg[NR14] = reg[NR14] & 0xf8 | fr >> 8;
rate(0, fr);
sweep(0);
rate(&sndch[0], fr);
sweep(0, t);
}
}
@ -187,6 +249,7 @@ sndstart(chan *c, u8int v)
{
u8int cnt;
filter(0);
c->vol = *c->env >> 4;
c->ectr = *c->env & 7;
if(c->len == 0)
@ -200,80 +263,46 @@ sndstart(chan *c, u8int v)
sweepfreq = v << 8 & 0x700 | reg[NR13];
sweepcalc = 0;
if((cnt & 0x07) != 0)
sweep(0);
sweep(0, 0);
}
if((*c->freq & 0x40) == 0 && (v & 0x40) != 0 && (envmod & 1) != 0 && --c->len == 0 || (*c->env & 0xf8) == 0){
apustatus &= ~(1<<c->n);
c->vol = 0;
}
chansamp(c, 0);
}
void
envtick(void *)
{
addevent(&evenv, FREQ / 512);
env(&sndch[0]);
env(&sndch[1]);
env(&sndch[0], evenv.time);
env(&sndch[1], evenv.time);
if((envmod & 1) == 0 && sndch[2].len > 0 && (reg[NR34] & 0x40) != 0)
if(--sndch[2].len == 0){
apustatus &= ~4;
delevent(&evwave);
delevent(&chev[2]);
}
env(&sndch[3]);
env(&sndch[3], evenv.time);
if((envmod & 3) == 2 && sweepen && --sweepctr == 0){
sweepctr = reg[NR10] >> 4 & 7;
sweepctr += sweepctr - 1 & 8;
if((reg[NR10] & 0x70) != 0)
sweep(1);
sweep(1, evenv.time);
}
envmod++;
addevent(&evenv, FREQ / 512);
}
void
sampletick(void *)
{
u8int cntl, cnth;
s16int ch[4];
s16int s[2];
int i;
addevent(&evsamp, SRATEDIV);
sndch[0].fctr += sndch[0].finc;
if(sndch[0].fctr >= sndch[0].fthr)
ch[0] = sndch[0].vol;
else
ch[0] = 0;
sndch[1].fctr += sndch[1].finc;
if(sndch[1].fctr >= sndch[1].fthr)
ch[1] = sndch[1].vol;
else
ch[1] = 0;
ch[2] = wavesamp();
ch[3] = lfsrsamp();
cntl = reg[NR50];
cnth = reg[NR51];
s[0] = 0;
s[1] = 0;
for(i = 0; i < 4; i++){
if(i == 2 ? ((reg[NR30] & 0x80) == 0) : ((*sndch[i].env & 0xf8) == 0))
continue;
ch[i] = ch[i] * 2 - 15;
if((cnth & 1<<i) != 0)
s[0] += ch[i];
if((cnth & 1<<4<<i) != 0)
s[1] += ch[i];
}
s[0] *= 1 + (cntl & 7);
s[1] *= 1 + (cntl >> 4 & 7);
filter(evsamp.time);
if(sbufp < sbuf + nelem(sbuf)){
sbufp[0] = s[0] * 30;
sbufp[1] = s[1] * 30;
sbufp[0] = samp[0] * 30;
sbufp[1] = samp[1] * 30;
sbufp += 2;
}
addevent(&evsamp, SRATEDIV);
}
void
@ -299,7 +328,6 @@ sndwrite(u8int a, u8int v)
}
break;
case NR11:
sndch[0].fthr = thr[v >> 6 & 3];
sndch[0].len = 64 - (v & 63);
break;
case NR12:
@ -309,15 +337,14 @@ sndwrite(u8int a, u8int v)
}
break;
case NR13:
rate(0, reg[NR14] << 8 & 0x700 | v);
rate(&sndch[0], reg[NR14] << 8 & 0x700 | v);
break;
case NR14:
rate(0, v << 8 & 0x700 | reg[NR13]);
rate(&sndch[0], v << 8 & 0x700 | reg[NR13]);
if((v & 1<<7) != 0)
sndstart(&sndch[0], v);
break;
case NR21:
sndch[1].fthr = thr[v >> 6 & 3];
sndch[1].len = 64 - (v & 63);
break;
case NR22:
@ -327,35 +354,35 @@ sndwrite(u8int a, u8int v)
}
break;
case NR23:
rate(1, reg[NR24] << 8 & 0x700 | v);
rate(&sndch[1], reg[NR24] << 8 & 0x700 | v);
break;
case NR24:
rate(1, v << 8 & 0x700 | reg[NR23]);
rate(&sndch[1], v << 8 & 0x700 | reg[NR23]);
if((v & 1<<7) != 0)
sndstart(&sndch[1], v);
break;
case NR30:
if((v & 0x80) == 0){
apustatus &= ~4;
delevent(&evwave);
delevent(&chev[2]);
}
break;
case NR31:
sndch[2].len = 256 - (v & 0xff);
break;
case NR33:
rate(2, reg[NR34] << 8 & 0x700 | v);
rate(&sndch[2], reg[NR34] << 8 & 0x700 | v);
break;
case NR34:
rate(2, v << 8 & 0x700 | reg[NR33]);
rate(&sndch[2], v << 8 & 0x700 | reg[NR33]);
if((v & 0x80) != 0){
if(sndch[2].len == 0)
sndch[2].len = 256;
wpos = 0;
if((reg[NR30] & 0x80) != 0){
apustatus |= 4;
delevent(&evwave);
addevent(&evwave, sndch[2].finc);
delevent(&chev[2]);
addevent(&chev[2], sndch[2].per);
}
}
break;
@ -369,7 +396,7 @@ sndwrite(u8int a, u8int v)
}
break;
case NR43:
rate(3, v);
rate(&sndch[3], v);
break;
case NR44:
if((v & 1<<7) != 0){
@ -380,6 +407,9 @@ sndwrite(u8int a, u8int v)
sndstart(&sndch[3], v);
}
break;
case NR50: case NR51:
filter(0);
break;
case NR52:
apustatus = v & 0xf0 | apustatus & 0x0f;
if((v & 0x80) == 0){
@ -390,15 +420,14 @@ sndwrite(u8int a, u8int v)
sndch[2].len = 0;
sndch[3].len = 0;
apustatus = 0;
delevent(&evwave);
delevent(&chev[2]);
}
}else if((reg[NR52] & 0x80) == 0){
envmod = 0;
delevent(&evenv);
addevent(&evenv, FREQ / 512);
sndch[0].fctr = 0;
sndch[1].fctr = 0;
sndch[3].fctr = 0;
sndch[0].ctr = 0;
sndch[1].ctr = 0;
}
}
reg[a] = v;
@ -430,6 +459,9 @@ audioinit(void)
sbufp = sbuf;
evsamp.f = sampletick;
addevent(&evsamp, SRATEDIV);
addevent(&chev[0], 8 * 2048);
addevent(&chev[1], 8 * 2048);
addevent(&chev[3], 8 * 2048);
}
int

2
sys/src/games/gb/dat.h
View File

@ -155,6 +155,6 @@ struct Var {
};
#define VAR(a) {&a, sizeof(a), 1}
#define ARR(a) {a, sizeof(*a), nelem(a)}
enum { NEVENT = 5 };
enum { NEVENT = 8 };
extern int (*mapper)(int, int);
extern u32int moncols[4];

12
sys/src/games/gb/ev.c
View File

@ -4,9 +4,9 @@
#include "dat.h"
#include "fns.h"
Event evhblank, evtimer, evenv, evwave;
extern Event evsamp;
Event *events[NEVENT] = {&evhblank, &evtimer, &evenv, &evsamp, &evwave};
Event evhblank, evtimer, evenv;
extern Event evsamp, chev[4];
Event *events[NEVENT] = {&evhblank, &evtimer, &evenv, &evsamp, &chev[0], &chev[1], &chev[2], &chev[3]};
Event *elist;
static int timshtab[4] = {12, 4, 6, 8}, timsh;
ulong timclock;
@ -109,11 +109,15 @@ eventinit(void)
extern void hblanktick(void *);
extern void envtick(void *);
extern void wavetick(void *);
extern void chantick(void *);
evhblank.f = hblanktick;
addevent(&evhblank, 240*4);
evtimer.f = timertick;
evenv.f = envtick;
addevent(&evenv, FREQ / 512);
evwave.f = wavetick;
chev[0].f = chantick;
chev[1].f = chantick;
chev[2].f = chantick;
chev[3].f = chantick;
}

5
sys/src/games/gb/gb.c
View File

@ -222,6 +222,7 @@ keyproc(void *)
static char buf[256];
char *s;
Rune r;
extern double TAU;
fd = open("/dev/kbd", OREAD);
if(fd < 0)
@ -240,6 +241,10 @@ keyproc(void *)
}
if(utfrune(buf, 't'))
trace = !trace;
if(utfrune(buf, KF|9))
TAU += 5000;
if(utfrune(buf, KF|10))
TAU -= 5000;
}
if(buf[0] != 'k' && buf[0] != 'K')
continue;