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games/nes: best commit (fixed audio and timing)

--- a/sys/src/games/nes/apu.c

+++ b/sys/src/games/nes/apu.c

@@ -5,11 +5,12 @@

 #include "dat.h"

 #include "fns.h"

+enum { MAXBUF = 2000 };

+

 u8int apuseq, apuctr[10];

 static int fd;

+static short sbuf[2*MAXBUF], *sbufp;

-enum { RATE = 44100 };

-

 int

 targperiod(int i)

 {

@@ -204,31 +205,36 @@

 	return 0;

 }

-static void

-sample(short *s)

+void

+audiosample(void)

 {

 	double d;

+	if(sbufp == nil)

+		return;

 	d = 95.88 / (8128.0 / (0.01 + pulse(0) + pulse(1)) + 100);

 	d += 159.79 / (1.0 / (0.01 + tri()/8227.0 + noise()/12241.0 + dmc()/22638.0) + 100.0);

-	*s++ = d * 20000;

-	*s = d * 20000;

+	if(sbufp < sbuf + nelem(sbuf) - 1){

+		*sbufp++ = d * 20000;

+		*sbufp++ = d * 20000;

+	}

 }

-static void

-audioproc(void *)

+int

+audioout(void)

 {

-	static short samples[500 * 2];

-	int i;

+	int rc;

-	for(;;){

-		if(paused)

-			memset(samples, 0, sizeof samples);

-		else

-			for(i = 0; i < sizeof samples/4; i++)

-				sample(samples + 2 * i);

-		write(fd, samples, sizeof samples);

-	}

+	if(sbufp == nil)

+		return -1;

+	if(sbufp == sbuf)

+		return 0;

+	rc = write(fd, sbuf, (sbufp - sbuf) * 2);

+	if(rc > 0)

+		sbufp -= (rc+1)/2;

+	if(sbufp < sbuf)

+		sbufp = sbuf;

+	return 0;

 }

 void

@@ -237,7 +243,7 @@

 	fd = open("/dev/audio", OWRITE);

 	if(fd < 0)

 		return;

-	proccreate(audioproc, nil, 8192);

+	sbufp = sbuf;

 }

 u8int apulen[32] = {

--- a/sys/src/games/nes/dat.h

+++ b/sys/src/games/nes/dat.h

@@ -76,6 +76,8 @@

 	MILLION = 1000000,

 	BILLION = 1000000000,

 	APUDIV = 89490,

+	RATE = 44100,

+	SAMPDIV = FREQ / RATE,

 	SAVEFREQ = FREQ/5,

 };

--- a/sys/src/games/nes/fns.h

+++ b/sys/src/games/nes/fns.h

@@ -11,3 +11,5 @@

 int	get8(void);

 void	apustep(void);

 void	initaudio(void);

+void	audiosample(void);

+int	audioout(void);

--- a/sys/src/games/nes/nes.c

+++ b/sys/src/games/nes/nes.c

@@ -13,7 +13,7 @@

 int scale;

 Rectangle picr;

 Image *tmp, *bg;

-int clock, ppuclock, apuclock, syncclock, syncfreq, checkclock, msgclock, saveclock, sleeps;

+int clock, ppuclock, apuclock, sampclock, msgclock, saveclock;

 Mousectl *mc;

 int keys, paused, savereq, loadreq, oflag, savefd = -1;

 int mirr;

@@ -184,7 +184,6 @@

 {

 	int t, h, sflag;

 	Point p;

-	uvlong old, new, diff;

 	scale = 1;

 	h = 240;

@@ -231,8 +230,6 @@

 	pc = memread(0xFFFC) | memread(0xFFFD) << 8;

 	rP = FLAGI;

-	syncfreq = FREQ / 30;

-	old = nsec();

 	for(;;){

 		if(savereq){

 			savestate("nes.save");

@@ -250,8 +247,9 @@

 		clock += t;

 		ppuclock += t;

 		apuclock += t;

-		syncclock += t;

-		checkclock += t;

+		sampclock += t;

+		//syncclock += t;

+		//checkclock += t;

 		while(ppuclock >= 4){

 			ppustep();

 			ppuclock -= 4;

@@ -260,24 +258,9 @@

 			apustep();

 			apuclock -= APUDIV;

 		}

-		if(syncclock >= syncfreq){

-			sleep(10);

-			sleeps++;

-			syncclock = 0;

-		}

-		if(checkclock >= FREQ){

-			new = nsec();

-			diff = new - old - sleeps * 10 * MILLION;

-			diff = BILLION - diff;

-			if(diff <= 0)

-				syncfreq = FREQ;

-			else

-				syncfreq = ((vlong)FREQ) * 10 * MILLION / diff;

-			if(syncfreq < FREQ / 100)

-				syncfreq = FREQ / 100;

-			old = new;

-			checkclock = 0;

-			sleeps = 0;

+		if(sampclock >= SAMPDIV){

+			audiosample();

+			sampclock -= SAMPDIV;

 		}

 		if(msgclock > 0){

 			msgclock -= t;

--- a/sys/src/games/nes/ppu.c

+++ b/sys/src/games/nes/ppu.c

@@ -255,6 +255,8 @@

 	extern Rectangle picr;

 	extern Image *tmp, *bg;

 	extern Mousectl *mc;

+	static vlong old, diff;

+	vlong new;

 	Mouse m;

 	Point p;

 	int h;

@@ -282,6 +284,15 @@

 		loadimage(screen, picr, pic + oflag*8*256*4*scale*scale, 256*h*4*scale*scale);

 	flushimage(display, 1);

 	memset(pic, sizeof pic, 0);

+	if(audioout() < 0){

+		new = nsec();

+		if(old != 0){

+			diff = BILLION/60 - (new - old);

+			if(diff >= MILLION)

+				sleep(diff/MILLION);

+		}

+		old = new;

+	}

 }

 void