shithub: riscv

Download patch

ref: f14b49f8bf736dc9cd9b3bd596d3ff2bbfd3116a
parent: f783587f05a9839b92d986eb7268981f7894e054
author: aiju <devnull@localhost>
date: Mon Mar 17 14:56:00 EDT 2014 

games/snes: audio support (kind of)


--- a/sys/src/games/snes/dat.h
+++ b/sys/src/games/snes/dat.h
@@ -1,3 +1,6 @@
+typedef signed char s8int;
+typedef signed short s16int;
+
 extern u16int pc;
 extern u32int rPB, curpc;
 extern u8int dma, nmi, irq;
@@ -13,8 +16,9 @@
 extern int ppux, ppuy, rx;
 extern u16int vtime, htime, subcolor, oamaddr;
 extern u16int hofs[5], vofs[5];
-typedef signed short s16int;
 extern s16int m7[6];
+
+extern u8int spcmem[65536];
 
 extern int battery, saveclock, scale, mouse;
 
--- /dev/null
+++ b/sys/src/games/snes/dsp.c
@@ -1,0 +1,602 @@
+#include <u.h>
+#include <libc.h>
+#include <thread.h>
+#include "dat.h"
+#include "fns.h"
+
+static u8int dsp[256], dspstate;
+static u16int counter, noise;
+static s16int samp[2], echoin[2];
+
+enum {
+	VOLL = 0,
+	VOLR = 1,
+	PITCHL = 2,
+	PITCHH = 3,
+	SRCN = 4,
+	ADSR1 = 5,
+	ADSR2 = 6,
+	GAIN = 7,
+	ENVX = 8,
+	OUTX = 9,
+	MVOLL = 0x0c,
+	EFB = 0x0d,
+	MVOLR = 0x1c,
+	EVOLL = 0x2c,
+	EVOLR = 0x2d,
+	PMON = 0x2d,
+	NON = 0x3d,
+	EON = 0x4d,
+	KON = 0x4c,
+	KOFF = 0x5c,
+	DIR = 0x5d,
+	FLG = 0x6c,
+	ENDX = 0x7c,
+	NEWKON = 0x8e,
+	INT = 0x80,
+};
+
+enum {
+	READY = 6,
+};
+
+enum { RELEASE, ATTACK, DECAY, SUSTAIN };
+
+static s16int sbuf[2*2000], *sbufp;
+static int fd;
+
+void
+audioinit(void)
+{
+	int cfd;
+	static char c[] = "speed 32000";
+
+	fd = open("/dev/audio", OWRITE);
+	if(fd < 0)
+		return;
+	cfd = open("/dev/volume", OWRITE);
+	if(cfd >= 0)
+		write(cfd, c, sizeof(c));
+	sbufp = sbuf;
+}
+
+static void
+audiosample(s16int *s)
+{
+	if(sbufp < sbuf + nelem(sbuf)){
+		*sbufp++ = s[0];
+		*sbufp++ = s[1];
+	}
+}
+
+int
+audioout(void)
+{
+	int rc;
+
+	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;
+}
+
+static u16int
+spc16(u16int p)
+{
+	u16int v;
+	
+	v = spcmem[p++];
+	v |= spcmem[p] << 8;
+	return v;
+}
+
+u8int
+dspread(u8int p)
+{
+	p &= 0x7f;
+	return dsp[p];
+}
+
+void
+dspwrite(u8int p, u8int v)
+{
+	if(p >= 0x80)
+		return;
+	switch(p){
+	case 0x4c:
+		dsp[NEWKON] = v;
+		break;
+	case 0x7c:
+		v = 0;
+		break;
+	}
+	dsp[p] = v;
+}
+
+int
+envyes(int r)
+{
+	static u16int modulus[] = {
+		0, 2048, 1536, 1280, 1024, 768, 640, 512, 384,
+		320, 256, 192, 160, 128, 96, 80, 64, 48,
+		40, 32, 24, 20, 16, 12, 10, 8, 6, 5, 4, 3,
+	};
+	u16int c;
+	
+	if(r == 0)
+		return 0;
+	if(r >= 30){
+		if(r == 31)
+			return 1;
+		return (counter & 1) == 0;
+	}
+	c = counter;
+	switch(r % 3){
+	case 0: c += 536; break;
+	case 2: c += 1040; break;
+	}
+	return c % modulus[r] == 0;
+}
+
+static s16int
+clamp16(int v)
+{
+	if(v < -32768)
+		return -32768;
+	if(v > 32767)
+		return 32767;
+	return v;
+}
+
+typedef struct {
+	int n;
+	u8int *r;
+	
+	u16int hdrp, dp, sp;
+	u8int hdr;
+	u16int brr;
+
+	u8int envst;
+	u16int env, envbent;
+	
+	u8int init;
+	u16int interp;
+	s16int buf[12];
+	
+	u16int pitch;
+	s16int sample, modin;
+} vctxt;
+vctxt vctxts[8];
+
+static void
+env(vctxt *p)
+{
+	u8int *r, a, g;
+	
+	r = p->r;
+	a = r[INT|ADSR1];
+	if((a & 0x80) != 0)
+		g = r[ADSR2];
+	else
+		g = r[GAIN];
+	if(p->envst == RELEASE)
+		p->env -= 8;
+	else if((a & 0x80) != 0){
+		switch(p->envst){
+		case ATTACK:
+			if(envyes((a & 0xf) << 1 | 1))
+				p->env += (a & 0xf) == 0xf ? 1024 : 32;
+			break;
+		case DECAY:
+			if(envyes(a >> 3 & 0xe | 0x10))
+				p->env -= ((p->env - 1) >> 8) + 1;
+			break;
+		case SUSTAIN:
+			if(envyes(g & 0x1f))
+				p->env -= ((p->env - 1) >> 8) + 1;
+			break;
+		}
+	}else{
+		if((g & 0x80) != 0){
+			if(envyes(g & 0x1f))
+				switch((g >> 5) & 3){
+				case 0: p->env -= 32; break;
+				case 1: p->env -= ((p->env - 1) >> 8) + 1; break;
+				case 2: p->env += 32; break;
+				case 3:
+					if(p->envbent < 0x600)
+						p->env += 32;
+					else
+						p->env += 8;
+					break;
+				}
+		}else
+			p->env = g << 4;
+	}
+	p->envbent = p->env & 0x7ff;
+	if((p->env & 0x8000) != 0)
+		p->env = 0;
+	else if(p->env > 0x7ff){
+		p->env = 0x7ff;
+		if(p->envst == ATTACK){
+			p->envst = DECAY;
+			return;
+		}
+	}
+	if(p->envst == DECAY && (p->env >> 8) == (g >> 5))
+		p->envst = SUSTAIN;
+}
+
+static void
+decode(vctxt *p)
+{
+	int i, d, s1, s2;
+	u8int f, s;
+	s16int brr;
+	
+	f = (p->hdr >> 2) & 3;
+	s = p->hdr >> 4;
+	brr = p->brr;
+	s1 = p->buf[7];
+	s2 = p->buf[6];
+	for(i = 0; i < 4; i++){
+		d = brr >> 12;
+		if(s >= 13)
+			d = d & ~0x7ff;
+		else{
+			d <<= s;
+			d >>= 1;
+		}
+		s2 >>= 1;
+		switch(f){
+		case 1:
+			d += s1 >> 1;
+			d += (-s1) >> 5;
+			break;
+		case 2:
+			d += s1;
+			d -= s2;
+			d += s2 >> 4;
+			d += (s1 * -3) >> 6;
+			break;
+		case 3:
+			d += s1;
+			d -= s2;
+			d += (s1 * -13) >> 7;
+			d += (s2 * 3) >> 4;
+			break;
+		}
+		d = (s16int)(clamp16(d) << 1);
+		p->buf[8 + i] = d;
+		s1 = d;
+		s2 = s1;
+		brr <<= 4;
+	}
+}
+
+static s16int
+interp(u16int x, s16int *s)
+{
+	extern u16int gauss[];
+	int v;
+	u8int i, d;
+
+	i = x >> 12;
+	d = x >> 4;
+	v  = ((int)gauss[255 - d] * s[i]) >> 11;
+	v += ((int)gauss[511 - d] * s[i+1]) >> 11;
+	v += ((int)gauss[256 + d] * s[i+2]) >> 11;
+	v = (s16int)v;
+	v += ((int)gauss[d] * s[i+3]) >> 11;
+	return clamp16(v) & ~1;
+}
+
+static void
+voice(int n, int s)
+{
+	vctxt *p;
+	u8int *r, m;
+	u16int a;
+	int v;
+	
+	p = vctxts + n;
+	r = p->r;
+	switch(s){
+	case 1:
+		r[INT|SRCN] = r[SRCN];
+		break;
+	case 2:
+		a = (dsp[INT|DIR] << 8) + (r[INT|SRCN] << 2);
+		if(p->init == READY)
+			a += 2;
+		p->sp = spc16(a);
+		p->pitch = r[PITCHL];
+		r[INT|ADSR1] = r[ADSR1];
+		break;
+	case 3:
+		p->pitch |= r[PITCHH] << 8 & 0x3f00;
+		if(n == 0)
+			break;
+	case 0x31:
+		p->hdr = spcmem[p->hdrp];
+		p->brr = spcmem[p->dp] << 8;
+		if(n == 0)
+			break;
+	case 0x32:
+		if((dsp[INT|PMON] & 0xfe & 1<<n) != 0)
+			p->pitch += ((p[-1].modin >> 5) * p->pitch) >> 10;
+		if(p->init < READY){
+			p->pitch = 0;
+			p->env = 0;
+		}
+		if((dsp[INT|NON] & 1<<n) != 0)
+			p->sample = noise;
+		p->sample = (((int)p->sample * p->env) >> 11) & ~1;
+		p->modin = p->sample;
+		r[INT|OUTX] = p->sample >> 8;
+		r[INT|ENVX] = p->env >> 4;
+		if((dsp[FLG] & 0x80) != 0 || (p->hdr & 3) == 1){
+			p->envst = RELEASE;
+			p->env = 0;
+		}
+		if((dsp[INT|KOFF] & 1<<n) != 0)
+			p->envst = RELEASE;
+		if((dsp[INT|KON] & 1<<n) != 0){
+			p->envst = ATTACK;
+			p->init = 0;
+		}
+		if(p->init >= READY - 1)
+			env(p);
+		break;
+	case 4:
+		v = (p->sample * ((s8int)r[VOLL])) >> 7;
+		samp[0] = clamp16(samp[0] + v);
+		if((dsp[INT|EON] & (1<<n)) != 0)
+			echoin[0] = clamp16(echoin[0] + v);
+		if(p->init == 1){
+			p->hdrp = p->sp;
+			p->dp = p->hdrp + 1;
+		}
+		if(p->interp >= 0x4000 || p->init <= 4 && p->init >= 2){
+			memmove(p->buf, p->buf + 4, 8 * sizeof(s16int));
+			p->brr |= spcmem[++p->dp];
+			if(++p->dp == p->hdrp + 9){
+				if((p->hdr & 1) != 0){
+					dsp[INT|ENDX] |= 1<<n;
+					p->hdrp = p->sp;
+				}else
+					p->hdrp += 9;
+				p->dp = p->hdrp + 1;
+			}
+			decode(p);
+		}
+		if(p->interp >= 0x4000)
+			p->interp -= 0x4000;
+		p->interp += p->pitch;
+		if(p->interp >= 0x7fff)
+			p->interp = 0x7fff;
+		break;
+	case 5:
+		v = (p->sample * ((s8int)r[VOLR])) >> 7;
+		samp[1] = clamp16(samp[1] + v);
+		if((dsp[INT|EON] & (1<<n)) != 0)
+			echoin[1] = clamp16(echoin[1] + v); 
+		p->sample = interp(p->interp, p->buf);
+		break;
+	case 7:
+		m = 1<<n;
+		if(p->init == 0)
+			dsp[INT|ENDX] &= ~m;
+		dsp[ENDX] = dsp[ENDX] & ~m | dsp[INT|ENDX] & m;
+		break;
+	case 8:
+		r[OUTX] = r[INT|OUTX];
+		break;
+	case 9:
+		r[ENVX] = r[INT|ENVX];
+		if(p->init < READY)
+			p->init++;
+		break;
+	}
+}
+
+static void
+echo(int s)
+{
+	static s16int echoout[2];
+	static u8int fir[8];
+	int a, b;
+
+	switch(s){
+	case 22:
+		echoout[0] = 0;
+		fir[0] = dsp[0x0f];
+		break;
+	case 23:
+		fir[1] = dsp[0x1f];
+		fir[2] = dsp[0x2f];
+		break;
+	case 24:
+		fir[3] = dsp[0x3f];
+		fir[4] = dsp[0x4f];
+		fir[5] = dsp[0x5f];
+		break;
+	case 25:
+		fir[6] = dsp[0x6f];
+		fir[7] = dsp[0x7f];
+		break;
+	case 26:
+		a = (samp[0] * (s8int)dsp[MVOLL]) >> 7;
+		b = (echoout[0] * (s8int)dsp[EVOLL]) >> 7;
+		samp[0] = clamp16(a + b);
+		echoin[0] = (echoin[0] * (s8int)dsp[EFB]) >> 7;
+		echoin[1] = (echoin[1] * (s8int)dsp[EFB]) >> 7;
+		break;
+	case 27:
+		a = (samp[1] * (s8int)dsp[MVOLR]) >> 7;
+		b = (echoout[1] * (s8int)dsp[EVOLR]) >> 7;
+		samp[1] = clamp16(a + b);
+		break;
+	case 28:
+		dsp[INT|FLG] = dsp[FLG];
+		break;
+	case 29:
+		dsp[INT|FLG] = dsp[FLG];
+		break;
+	case 30:
+		break;
+	}
+}
+
+void
+dspstep(void)
+{
+	if(sbufp == nil)
+		return;
+	switch(dspstate++ & 31){
+	case  0: voice(0, 5); voice(1, 2); break;
+	case  1: voice(0, 6); voice(1, 3); break;
+	case  2: voice(0, 7); voice(1, 4); voice(3, 1); break;
+	case  3: voice(0, 8); voice(1, 5); voice(2, 2); break;
+	case  4: voice(0, 9); voice(1, 6); voice(2, 3); break;
+	case  5: voice(1, 7); voice(2, 4); voice(4, 1); break;
+	case  6: voice(1, 8); voice(2, 5); voice(3, 2); break;
+	case  7: voice(1, 9); voice(2, 6); voice(3, 3); break;
+	case  8: voice(2, 7); voice(3, 4); voice(5, 1); break;
+	case  9: voice(2, 8); voice(3, 5); voice(4, 2); break;
+	case 10: voice(2, 9); voice(3, 6); voice(4, 3); break;
+	case 11: voice(3, 7); voice(4, 4); voice(6, 1); break;
+	case 12: voice(3, 8); voice(4, 5); voice(5, 2); break;
+	case 13: voice(3, 9); voice(4, 6); voice(5, 3); break;
+	case 14: voice(4, 7); voice(5, 4); voice(7, 1); break;
+	case 15: voice(4, 8); voice(5, 5); voice(6, 2); break;
+	case 16: voice(4, 9); voice(5, 6); voice(6, 3); break;
+	case 17: voice(5, 7); voice(6, 4); voice(0, 1); break;
+	case 18: voice(5, 8); voice(6, 5); voice(7, 2); break;
+	case 19: voice(5, 9); voice(6, 6); voice(7, 3); break;
+	case 20: voice(6, 7); voice(7, 4); voice(1, 1); break;
+	case 21: voice(6, 8); voice(7, 5); voice(0, 2); break;
+	case 22: voice(6, 9); voice(7, 6); voice(0, 3); echo(22); break;
+	case 23: voice(7, 7); echo(23); break;
+	case 24: voice(7, 8); echo(24); break;
+	case 25: voice(7, 9); voice(0, 0x31); echo(25); break;
+	case 26: echo(26); break;
+	case 27:
+		dsp[INT|PMON] = dsp[PMON];
+		echo(27);
+		if((dsp[FLG] & 0x40) != 0)
+			samp[0] = samp[1] = 0;
+		audiosample(samp);
+		samp[0] = samp[1] = 0;
+		break;
+	case 28:
+		dsp[INT|NON] = dsp[NON];
+		dsp[INT|EON] = dsp[EON];
+		dsp[INT|DIR] = dsp[DIR];
+		echo(28);
+		break;
+	case 29:
+		echo(29);
+		if((dspstate & 64) == 0)
+			dsp[NEWKON] &= ~dsp[INT|KON];
+		break;
+	case 30:
+		voice(0, 0x32);
+		echo(30);
+		if((dspstate & 64) == 0){
+			dsp[INT|KOFF] = dsp[KOFF];
+			dsp[INT|KON] = dsp[NEWKON];
+		}
+		if(counter-- == 0)
+			counter = 0x77ff;
+		break;
+	case 31: voice(0, 4); voice(2, 1); break;
+	}
+}
+
+void
+dspreset(void)
+{
+	vctxt *p;
+	int i;
+	
+	for(i = 0; i < 8; i++){
+		p = vctxts + i;
+		p->n = i;
+		p->r = dsp + (i << 4);
+	}
+	dsp[FLG] = 0xe0;
+}
+
+u16int gauss[512] = {
+	0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000,
+	0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000,
+	0x001, 0x001, 0x001, 0x001, 0x001, 0x001, 0x001, 0x001,
+	0x001, 0x001, 0x001, 0x002, 0x002, 0x002, 0x002, 0x002,
+	0x002, 0x002, 0x003, 0x003, 0x003, 0x003, 0x003, 0x004,
+	0x004, 0x004, 0x004, 0x004, 0x005, 0x005, 0x005, 0x005,
+	0x006, 0x006, 0x006, 0x006, 0x007, 0x007, 0x007, 0x008,
+	0x008, 0x008, 0x009, 0x009, 0x009, 0x00A, 0x00A, 0x00A,
+	0x00B, 0x00B, 0x00B, 0x00C, 0x00C, 0x00D, 0x00D, 0x00E,
+	0x00E, 0x00F, 0x00F, 0x00F, 0x010, 0x010, 0x011, 0x011,
+	0x012, 0x013, 0x013, 0x014, 0x014, 0x015, 0x015, 0x016,
+	0x017, 0x017, 0x018, 0x018, 0x019, 0x01A, 0x01B, 0x01B,
+	0x01C, 0x01D, 0x01D, 0x01E, 0x01F, 0x020, 0x020, 0x021,
+	0x022, 0x023, 0x024, 0x024, 0x025, 0x026, 0x027, 0x028,
+	0x029, 0x02A, 0x02B, 0x02C, 0x02D, 0x02E, 0x02F, 0x030,
+	0x031, 0x032, 0x033, 0x034, 0x035, 0x036, 0x037, 0x038,
+	0x03A, 0x03B, 0x03C, 0x03D, 0x03E, 0x040, 0x041, 0x042,
+	0x043, 0x045, 0x046, 0x047, 0x049, 0x04A, 0x04C, 0x04D,
+	0x04E, 0x050, 0x051, 0x053, 0x054, 0x056, 0x057, 0x059,
+	0x05A, 0x05C, 0x05E, 0x05F, 0x061, 0x063, 0x064, 0x066,
+	0x068, 0x06A, 0x06B, 0x06D, 0x06F, 0x071, 0x073, 0x075,
+	0x076, 0x078, 0x07A, 0x07C, 0x07E, 0x080, 0x082, 0x084,
+	0x086, 0x089, 0x08B, 0x08D, 0x08F, 0x091, 0x093, 0x096,
+	0x098, 0x09A, 0x09C, 0x09F, 0x0A1, 0x0A3, 0x0A6, 0x0A8,
+	0x0AB, 0x0AD, 0x0AF, 0x0B2, 0x0B4, 0x0B7, 0x0BA, 0x0BC,
+	0x0BF, 0x0C1, 0x0C4, 0x0C7, 0x0C9, 0x0CC, 0x0CF, 0x0D2,
+	0x0D4, 0x0D7, 0x0DA, 0x0DD, 0x0E0, 0x0E3, 0x0E6, 0x0E9,
+	0x0EC, 0x0EF, 0x0F2, 0x0F5, 0x0F8, 0x0FB, 0x0FE, 0x101,
+	0x104, 0x107, 0x10B, 0x10E, 0x111, 0x114, 0x118, 0x11B,
+	0x11E, 0x122, 0x125, 0x129, 0x12C, 0x130, 0x133, 0x137,
+	0x13A, 0x13E, 0x141, 0x145, 0x148, 0x14C, 0x150, 0x153,
+	0x157, 0x15B, 0x15F, 0x162, 0x166, 0x16A, 0x16E, 0x172,
+	0x176, 0x17A, 0x17D, 0x181, 0x185, 0x189, 0x18D, 0x191,
+	0x195, 0x19A, 0x19E, 0x1A2, 0x1A6, 0x1AA, 0x1AE, 0x1B2,
+	0x1B7, 0x1BB, 0x1BF, 0x1C3, 0x1C8, 0x1CC, 0x1D0, 0x1D5,
+	0x1D9, 0x1DD, 0x1E2, 0x1E6, 0x1EB, 0x1EF, 0x1F3, 0x1F8,
+	0x1FC, 0x201, 0x205, 0x20A, 0x20F, 0x213, 0x218, 0x21C,
+	0x221, 0x226, 0x22A, 0x22F, 0x233, 0x238, 0x23D, 0x241,
+	0x246, 0x24B, 0x250, 0x254, 0x259, 0x25E, 0x263, 0x267,
+	0x26C, 0x271, 0x276, 0x27B, 0x280, 0x284, 0x289, 0x28E,
+	0x293, 0x298, 0x29D, 0x2A2, 0x2A6, 0x2AB, 0x2B0, 0x2B5,
+	0x2BA, 0x2BF, 0x2C4, 0x2C9, 0x2CE, 0x2D3, 0x2D8, 0x2DC,
+	0x2E1, 0x2E6, 0x2EB, 0x2F0, 0x2F5, 0x2FA, 0x2FF, 0x304,
+	0x309, 0x30E, 0x313, 0x318, 0x31D, 0x322, 0x326, 0x32B,
+	0x330, 0x335, 0x33A, 0x33F, 0x344, 0x349, 0x34E, 0x353,
+	0x357, 0x35C, 0x361, 0x366, 0x36B, 0x370, 0x374, 0x379,
+	0x37E, 0x383, 0x388, 0x38C, 0x391, 0x396, 0x39B, 0x39F,
+	0x3A4, 0x3A9, 0x3AD, 0x3B2, 0x3B7, 0x3BB, 0x3C0, 0x3C5,
+	0x3C9, 0x3CE, 0x3D2, 0x3D7, 0x3DC, 0x3E0, 0x3E5, 0x3E9,
+	0x3ED, 0x3F2, 0x3F6, 0x3FB, 0x3FF, 0x403, 0x408, 0x40C,
+	0x410, 0x415, 0x419, 0x41D, 0x421, 0x425, 0x42A, 0x42E,
+	0x432, 0x436, 0x43A, 0x43E, 0x442, 0x446, 0x44A, 0x44E,
+	0x452, 0x455, 0x459, 0x45D, 0x461, 0x465, 0x468, 0x46C,
+	0x470, 0x473, 0x477, 0x47A, 0x47E, 0x481, 0x485, 0x488,
+	0x48C, 0x48F, 0x492, 0x496, 0x499, 0x49C, 0x49F, 0x4A2,
+	0x4A6, 0x4A9, 0x4AC, 0x4AF, 0x4B2, 0x4B5, 0x4B7, 0x4BA,
+	0x4BD, 0x4C0, 0x4C3, 0x4C5, 0x4C8, 0x4CB, 0x4CD, 0x4D0,
+	0x4D2, 0x4D5, 0x4D7, 0x4D9, 0x4DC, 0x4DE, 0x4E0, 0x4E3,
+	0x4E5, 0x4E7, 0x4E9, 0x4EB, 0x4ED, 0x4EF, 0x4F1, 0x4F3,
+	0x4F5, 0x4F6, 0x4F8, 0x4FA, 0x4FB, 0x4FD, 0x4FF, 0x500,
+	0x502, 0x503, 0x504, 0x506, 0x507, 0x508, 0x50A, 0x50B,
+	0x50C, 0x50D, 0x50E, 0x50F, 0x510, 0x511, 0x511, 0x512,
+	0x513, 0x514, 0x514, 0x515, 0x516, 0x516, 0x517, 0x517,
+	0x517, 0x518, 0x518, 0x518, 0x518, 0x518, 0x519, 0x519
+};
--- a/sys/src/games/snes/fns.h
+++ b/sys/src/games/snes/fns.h
@@ -11,3 +11,9 @@
 int	hdmastep(void);
 void	flush(void);
 void	message(char *, ...);
+void	dspstep(void);
+u8int	dspread(u8int);
+void	dspwrite(u8int, u8int);
+void	dspreset(void);
+void	audioinit(void);
+int	audioout(void);
--- a/sys/src/games/snes/mem.c
+++ b/sys/src/games/snes/mem.c
@@ -288,11 +288,11 @@
 		if((v & 0x40) != 0) subcolor = subcolor & 0x7c1f | (v & 0x1f) << 5;
 		if((v & 0x20) != 0) subcolor = subcolor & 0x03ff | (v & 0x1f) << 10;
 		return;
+	case 0x213e:
+		return;
 	case 0x2180:
 		memwrite(0x7e0000 | reg[0x2181] | reg[0x2182] << 8 | (reg[0x2183] & 1) << 16, v);
 		incwram();
-		return;
-	case 0x213e:
 		return;
 	case 0x4016:
 		if((reg[0x4016] & 1) != 0 && (v & 1) == 0){
--- a/sys/src/games/snes/mkfile
+++ b/sys/src/games/snes/mkfile
@@ -8,6 +8,7 @@
 	mem.$O\
 	ppu.$O\
 	spc.$O\
+	dsp.$O\
 
 HFILES=dat.h fns.h
 
--- a/sys/src/games/snes/snes.c
+++ b/sys/src/games/snes/snes.c
@@ -11,7 +11,7 @@
 uchar *prg, *sram;
 int nprg, nsram, hirom, battery;
 
-int ppuclock, spcclock, stimerclock, saveclock, msgclock, paused, perfclock;
+int ppuclock, spcclock, dspclock, stimerclock, saveclock, msgclock, paused, perfclock;
 Mousectl *mc;
 QLock pauselock;
 u32int keys;
@@ -57,11 +57,14 @@
 	if(readn(fd, prg, size) < size)
 		sysfatal("read: %r");
 	close(fd);
-	if((memread(0xffd5) & ~0x10) != 0x20)
-		if((memread(0x1ffd5) & ~0x10) == 0x21)
-			hirom = 1;
-		else
-			sysfatal("invalid rom (neither hirom nor lorom)");
+	if(hirom < 0){
+		hirom = 0;
+		if((memread(0xffd5) & ~0x10) != 0x20)
+			if((memread(0x1ffd5) & ~0x10) == 0x21)
+				hirom = 1;
+			else
+				sysfatal("invalid rom (ffd5 = %.2x, 1ffd5 = %.2x)", memread(0xffd5), memread(0x1ffd5));
+	}
 	if(hirom)
 		nprg >>= 1;
 	switch(memread(0xffd6)){
@@ -201,6 +204,7 @@
 	extern u16int pc;
 
 	scale = 1;
+	hirom = -1;
 	ARGBEGIN {
 	case '2':
 		scale = 2;
@@ -208,6 +212,9 @@
 	case '3':
 		scale = 3;
 		break;
+	case 'a':
+		audioinit();
+		break;
 	case 's':
 		battery++;
 		break;
@@ -215,6 +222,9 @@
 		mouse++;
 		keys = 1<<16;
 		break;
+	case 'h':
+		hirom++;
+		break;
 	case 'T':
 		profile++;
 		break;
@@ -239,6 +249,7 @@
 	cpureset();
 	memreset();
 	spcreset();
+	dspreset();
 	for(;;){
 		if(paused){
 			qlock(&pauselock);
@@ -248,6 +259,7 @@
 		spcclock -= t;
 		stimerclock += t;
 		ppuclock += t;
+		dspclock += t;
 		perfclock -= t;
 
 		while(ppuclock >= 4){
@@ -260,6 +272,10 @@
 			spctimerstep();
 			stimerclock -= SPCDIV*16;
 		}
+		if(dspclock >= SPCDIV){
+			dspstep();
+			dspclock -= SPCDIV;
+		}
 		if(saveclock > 0){
 			saveclock -= t;
 			if(saveclock <= 0)
@@ -307,6 +323,7 @@
 	loadimage(tmp, tmp->r, pic, 256*239*2*scale*scale);
 	draw(screen, picr, tmp, nil, ZP);
 	flushimage(display, 1);
+	audioout();
 }
 
 void
--- a/sys/src/games/snes/spc.c
+++ b/sys/src/games/snes/spc.c
@@ -30,6 +30,8 @@
 		return ipl[p - 0xffc0];
 	if((p & 0xfff0) == 0x00f0)
 		switch(p){
+		case 0xf3:
+			return dspread(spcmem[0xf2]);
 		case 0xf4:
 		case 0xf5:
 		case 0xf6:
@@ -70,6 +72,9 @@
 			if((spcmem[0xf1] & 4) == 0 && (v & 4) != 0)
 				spctimer[2] = spcmem[0xff] = 0;
 			break;
+		case 0xf3:
+			dspwrite(spcmem[0xf2], v);
+			return;
 		case 0xfd:
 		case 0xfe:
 		case 0xff: