shithub: sms

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Wire audio

--- a/dat.h

+++ b/dat.h

@@ -56,6 +56,7 @@

 	FREQ = 53203400,

 	Z80DIV = 15,

 	RATE = 44100,

+	SAMPDIV = FREQ / RATE,

 	SAVEFREQ = FREQ / 4,

 	PSGCLOCK = 3579545,

 	PSGDIV = 16,

--- a/fns.h

+++ b/fns.h

@@ -17,7 +17,8 @@

 u8int vdpvcounter(void);

 void cramwrite(u16int, u8int);

 int audioout(void);

+void audiosample(void);

 void psginit(const u16int, const int);

 void psgwrite(const u8int);

-u16int psgstep();

+u16int psgstep(void);

 void mapperinit(void);

--- a/psg.c

+++ b/psg.c

@@ -58,7 +58,7 @@

 	return v;

 }

-static inline u16int

+static inline s16int

 vol(u8int chn)

 {

 	return (flipflop[chn] ? 1 : -1) * vol_table[attn[chn]];

@@ -65,7 +65,7 @@

 }

 u16int

-psgstep()

+psgstep(void)

 {

 	while(cyc > 0){

 		for(u8int i = 0; i < 4; i++){

@@ -93,6 +93,21 @@

 	return vol(0) + vol(1) + vol(2) + vol(3);

 }

+void

+audiosample(void)

+{

+	s16int v;

+

+	if(sbufp == nil)

+		return;

+

+	v = (s16int)psgstep();

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

+		*sbufp++ = v;

+		*sbufp++ = v;

+	}

+}

+

 int

 audioout(void)

 {

@@ -121,4 +136,4 @@

 		return;

 	sbufp = sbuf;

-}

\ No newline at end of file

+}

--- a/sms.c

+++ b/sms.c

@@ -103,10 +103,15 @@

 		process_inputs();

 		t = z80step();

 		vdpclock -= t * Z80DIV;

+		psgclock += t * Z80DIV;

 		while(vdpclock < 0){

 			vdpstep();

 			vdpclock += 8;

+		}

+		while(psgclock >= SAMPDIV){

+			audiosample();

+			psgclock -= SAMPDIV;

 		}

 	}

 }

-- 

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