break;
	case 10:
		sb_write_mix(base,0x80,8);
		break;
	default:
		printf("invalid irq %d\n",irq);
		return -1;
	}
	maskon(irq);
	if(dma8 < 0 || dma8 > 3 || dma8 == 2){
		printf("dma8 invalid\n");
		return -1;
	}
	if(dma16 < 5 || dma16 > 7){
		printf("dma16 invalid\n");
		return -1;
	}
	dis_dmaxl(dma16);
	dis_dmaxl(dma8);
	dma = (1 << dma16) | (1<<dma8);
	sb_write_mix(base,0x81,dma);

	return 0;
}
/* Enter A/D mode */
int
sb_adc(rate,stereo,bufsiz)
long rate;	/* Sampling rate, Hz */
int stereo;	/* 1 = stereo, 0 = mono */
int bufsiz;	/* Size of mbufs to be generated (1/2 DMA buffer) */
{
	if(Sb.base == 0){
		printf("No SB16 card attached\n");
		return -1;
	}
	if(Sb.state != IDLE){
		printf("SB16 not idle\n");
		return -1;
	}
	/* Allocate DMA buffer */
	if((Sb.ioptr = Sb.dmabuf = dma_malloc(&Sb.physaddr,2*bufsiz)) == NULL){
		printf("Can't alloc dma buffer\n");
		return -1;
	}
	Sb.state = ADC;
	Sb.dmasize = 2*bufsiz;
	setup_dma(Sb.dma16,Sb.physaddr,Sb.dmasize,0x54);

	/* Set sampling rate */
	sb_write_byte(Sb.base,0x42);
	sb_write_word_be(Sb.base,rate);

	sb_write_byte(Sb.base,0xbe);	/* 16-bit input, auto-init, fifo on */
	if(stereo)
		sb_write_byte(Sb.base,0x30);	/* stereo, signed */
	else
		sb_write_byte(Sb.base,0x10);	/* mono, signed */
	/* Write number of 16-bit words in half buffer, minus 1 */
	sb_write_word_le(Sb.base,Sb.dmasize/4-1);
	return 0;
}
/* Enter DAC mode */
int
sb_dac(rate,stereo,bufsiz)
long rate;	/* Sampling rate, Hz */
int stereo;	/* 1 = stereo, 0 = mono */
int bufsiz;	/* Size of buffer unit (1/2 DMA buffer) */
{
	if(Sb.base == 0){
		printf("No SB16 card attached\n");
		return -1;
	}
	if(Sb.state != IDLE){
		printf("SB16 not idle\n");
		return -1;
	}
	/* Allocate DMA buffer */
	if((Sb.ioptr = Sb.dmabuf = dma_malloc(&Sb.physaddr,2*bufsiz)) == NULL){
		printf("Can't alloc dma buffer\n");
		return -1;
	}
	Sb.state = DAC;
	Sb.dmasize = 2*bufsiz;
	Sb.stuffsamples = 0;
	Sb.bufcnt = 0;
	memset(Sb.dmabuf,0,Sb.dmasize);
	
	sb_write_byte(Sb.base,0xd1);	/* spkr on */
	setup_dma(Sb.dma16,Sb.physaddr,Sb.dmasize,0x58);

	/* Set up sampling rate */
	sb_write_byte(Sb.base,0x41);
	sb_write_word_be(Sb.base,rate);

	sb_write_byte(Sb.base,0xb6);	/* 16-bit output, auto-init, fifo on */
	if(stereo)
		sb_write_byte(Sb.base,0x30);	/* stereo, signed */
	else
		sb_write_byte(Sb.base,0x10);	/* mono, signed */
	/* Number of 16-bit words in a half-buffer, minus 1 */
	sb_write_word_le(Sb.base,Sb.dmasize/4-1);
	Sb.pause = 1;
	sb_write_byte(Sb.base,0xd5);	/* Pause until we get data */
	return 0;
}
/* Return soundblaster to idle condition */
int
sb_idle()
{
	switch(Sb.state){
	case IDLE:
		return 0;	/* Already idle */		
	case DAC:		/* Wait for output queue to drain */
	case ADC:
		/* stop conversion */
		sb_write_byte(Sb.base,0xd9);
		break;
	}
	Sb.state = IDLE;
	kwait(NULL);
	/* Ought to wait for last interrupt here */
	free_q(&Sb.sndq);
	free_q(&Sb.rcvq);
	dma_disable(Sb.dma16);
	dmaunlock(Sb.physaddr,Sb.dmasize);
	free(Sb.dmabuf);
	Sb.dmabuf = NULL;
	Sb.physaddr = 0;

	return 0;
}

/* Reset Soundblaster card */
static int
sb_reset(base)
int base;
{
	unsigned int i;

	outportb(base+SB_RESET,1);
	for(i=100;i !=0;i--)
		;
	outportb(base+SB_RESET,0);
	for(i=65535;i != 0;i--){
		if(sb_read_data(base) == 0xaa)
			break;
	}
	if(i == 0)
		return -1;
	return 0;
}
/* Wait for read data to become available, then read it. Return -1 on timeout */
static int
sb_read_data(base)
int base;
{
	unsigned int i;

	for(i=65535;i!=0;i--){
		if(inportb(base+SB_RB_STAT) & 0x80)
			break;
	}
	if(i == 0)
		return -1;	/* Timeout */
	return inportb(base+SB_READ_DATA);
}

/* Write data byte to soundblaster when it's ready. return 0 normally, -1 on err */
static int
sb_write_byte(base,data)
int base,data;
{
	int i;

	for(i=65535;i!=0;i--){
		if((inportb(base+SB_WB_STAT) & 0x80) == 0)
			break;
	}
	if(i == 0)
		return -1;
	outportb(base+SB_WB,data);
	return 0;
}
/* Write 16-bit word in big-endian order */
static int
sb_write_word_be(base,data)
int base;
short data;
{
	sb_write_byte(base,data >> 8);
	sb_write_byte(base,data);
	return 0;
}
/* Write 16-bit word in little-endian order */
static int
sb_write_word_le(base,data)
int base;
short data;
{
	sb_write_byte(base,data);
	sb_write_byte(base,data >> 8);
	return 0;
}
/* Read the mixer */
static int
sb_read_mix(base,reg)
int base,reg;
{
	outportb(base+SB_MIX_INDEX,reg);
	return inportb(base+SB_MIX_DATA);
}

/* Write data to soundblaster when it's ready. return 0 normally, -1 on err */
static int
sb_write_mix(base,reg,data)
int base,reg,data;
{
	outportb(base+SB_MIX_INDEX,reg);
	outportb(base+SB_MIX_DATA,data);
	return 0;
}

dosbcal(argc,argv,p)
int argc;
char *argv[];
void *p;
{
	long rate;

	rate = atol(argv[1]);
	sb_calibrate(rate);
	return 0;
}

/* Find DC offsets of each channel */
sb_calibrate(rate)
long rate;
{
	long leftavg,rightavg;
	uint8 omixl,omixr;
	long samples;

	/* Save previous mixer state,
	 * then turn everything off
	 */
	omixl = sb_read_mix(Sb.base,SB_INMIXL);
	omixr = sb_read_mix(Sb.base,SB_INMIXR);
	sb_write_mix(Sb.base,SB_INMIXL,0);		/* All inputs off */
	sb_write_mix(Sb.base,SB_INMIXR,0);

	/* Collect a second of samples */
	sb_adc(rate,1,TXBUF);
	ppause(1000L);
	sb_idle();

	/* Restore previous mixer switches */
	sb_write_mix(Sb.base,SB_INMIXL,omixl);
	sb_write_mix(Sb.base,SB_INMIXR,omixr);

	/* Analyze the data */
	leftavg = rightavg = 0;
	samples = 0;
	while(Sb.rcvq != NULL){
		uint16 left,right;

		left = pull16le(&Sb.rcvq);
		right = pull16le(&Sb.rcvq);

		leftavg += left;
		rightavg += right;		
		samples++;
	}
	leftavg /= samples;
	rightavg /= samples;
	printf("Left channel avg: %ld Right channel avg: %ld\n",
	 leftavg,rightavg);

	return 0;
}
unsigned short
pull16le(bpp)
struct mbuf **bpp;
{
	uint16 x;

	x = pull16(bpp);
	return (x >> 8) | (x << 8);
}
/* Copy as much of the buffer as will fit into the DMA buffer and start
 * the DAC if it was paused
 */
void
sb_outstart(bpp)
struct mbuf **bpp;
{
	int cnt;
	int istate;

	istate = dirps();
	/* Copy as much send queue data as we can into the DMA buffer */
	while(Sb.bufcnt < Sb.dmasize){
		cnt = min(Sb.dmasize-Sb.bufcnt,Sb.dmabuf+Sb.dmasize-Sb.ioptr);
		cnt = pullup(bpp,Sb.ioptr,cnt);
		if(cnt == 0)
			break;
		Sb.ioptr += cnt;
		if(Sb.ioptr >= Sb.dmabuf + Sb.dmasize)
			Sb.ioptr = Sb.dmabuf;	/* Write pointer wraparound */
		Sb.bufcnt += cnt;		/* Add to bytes in buffer */
	}
	if(!Sb.pause && Sb.bufcnt != 0 && Sb.bufcnt < Sb.dmasize/2){
		/* While running, pad out a partial half-buffer with silence */
		cnt = Sb.dmasize/2 - Sb.bufcnt;
		memset(Sb.ioptr,0,cnt);
		Sb.stuffsamples += cnt;
		Sb.ioptr += cnt;
		if(Sb.ioptr >= Sb.dmabuf + Sb.dmasize)
			Sb.ioptr = Sb.dmabuf;	/* Write pointer wraparound */
		Sb.bufcnt += cnt;
	} else if(Sb.pause && Sb.bufcnt >= Sb.dmasize/2){
		/* If paused and there's now at least one full buffer, resume */
		Sb.pause = 0;
		sb_write_byte(Sb.base,0xd6);	/* Resume output */
	}
	restore(istate);
}
/* Send a buffer to the DAC */
int
sb_send(bp)
struct mbuf *bp;
{
	if(Sb.state == DAC)
		sb_outstart(&bp);

	if(bp != NULL){
		/* Queue remainder */
		disable();
		append(&Sb.sndq,&bp);
		enable();
	}
	return 0;
}

/* Soundblaster interrupt handler */
INTERRUPT (far *(sbint)(dev))()
int dev;
{
	int i;
	struct mbuf *bp;

	i = sb_read_mix(Sb.base,0x82);
	if(i & 1)	/* 8-bit transfers not used, reset anyway */
		(void)inportb(Sb.base+0xe);
	if(i & 2){
		(void)inportb(Sb.base+0xf);
		switch(Sb.state){
		case IDLE:
			break;
		case DAC:
			Sb.bufcnt -= Sb.dmasize/2;	/* Amount sent */
			sb_outstart(&Sb.sndq);		/* Try to send more */
			if(Sb.bufcnt == 0){
				/* buffer empty, pause */
				Sb.pause = 1;
				sb_write_byte(Sb.base,0xd5);
			}
			break;
		case ADC:
			bp = alloc_mbuf(Sb.dmasize/2);
			memcpy(bp->data,Sb.ioptr,Sb.dmasize/2);
			bp->cnt = Sb.dmasize/2;
			Sb.ioptr += bp->cnt;
			if(Sb.ioptr >= Sb.dmabuf + Sb.dmasize)
				Sb.ioptr = Sb.dmabuf;
			enqueue(&Sb.rcvq,&bp);
			break;
		}
		ksignal(&Sb,0);
	}
	return NULL;
}