shithub: wl3d

ref: a0c3c62fcd25dd62d5c69353a604d3f6afbaa75b
dir: /sd.c/

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//
//	ID Engine
//	ID_SD.c - Sound Manager for Wolfenstein 3D
//	v1.2
//	By Jason Blochowiak
//

//
//	This module handles dealing with generating sound on the appropriate
//		hardware
//
//	Depends on: User Mgr (for parm checking)
//
//	Globals:
//		For User Mgr:
//			SoundSourcePresent - Sound Source thingie present?
//			SoundBlasterPresent - SoundBlaster card present?
//			AdLibPresent - AdLib card present?
//			SoundMode - What device is used for sound effects
//				(Use SM_SetSoundMode() to set)
//			MusicMode - What device is used for music
//				(Use SM_SetMusicMode() to set)
//			DigiMode - What device is used for digitized sound effects
//				(Use SM_SetDigiDevice() to set)
//
//		For Cache Mgr:
//			NeedsDigitized - load digitized sounds?
//			NeedsMusic - load music?
//

#pragma hdrstop		// Wierdo thing with MUSE

#include <dos.h>

#ifdef	_MUSE_      // Will be defined in ID_Types.h
#include "ID_SD.h"
#else
#include "ID_HEADS.H"
#endif
#pragma	hdrstop
#pragma	warn	-pia

#ifdef	nil
#undef	nil
#endif
#define	nil	0

#define	SDL_SoundFinished()	{SoundNumber = SoundPriority = 0;}

// Macros for SoundBlaster stuff
#define	sbOut(n,b)	outportb((n) + sbLocation,b)
#define	sbIn(n)		inportb((n) + sbLocation)
#define	sbWriteDelay()	while (sbIn(sbWriteStat) & 0x80);
#define	sbReadDelay()	while (sbIn(sbDataAvail) & 0x80);

// Macros for AdLib stuff
#define	selreg(n)	outportb(alFMAddr,n)
#define	writereg(n)	outportb(alFMData,n)
#define	readstat()	inportb(alFMStatus)

//	Imports from ID_SD_A.ASM
extern	void			SDL_SetDS(void),
						SDL_IndicatePC(int on);
extern	void interrupt	SDL_t0ExtremeAsmService(void),
						SDL_t0FastAsmService(void),
						SDL_t0SlowAsmService(void);

//	Global variables
	int		SoundSourcePresent,
				AdLibPresent,
				SoundBlasterPresent,SBProPresent,
				NeedsDigitized,NeedsMusic,
				SoundPositioned;
	SDMode		SoundMode;
	SMMode		MusicMode;
	SDSMode		DigiMode;
	u32int	TimeCount;
	u16int		HackCount;
	u16int		*SoundTable;	// Really * _seg *SoundTable, but that don't work
	int		ssIsTandy;
	u16int		ssPort = 2;
	s16int			DigiMap[LASTSOUND];

//	Internal variables
static	int			SD_Started;
		int			nextsoundpos;
		u32int		TimerDivisor,TimerCount;
static	char			*ParmStrings[] =
						{
							"noal",
							"nosb",
							"nopro",
							"noss",
							"sst",
							"ss1",
							"ss2",
							"ss3",
							nil
						};
static	void			(*SoundUserHook)(void);
		soundnames		SoundNumber,DigiNumber;
		u16int			SoundPriority,DigiPriority;
		s16int				LeftPosition,RightPosition;
		void interrupt	(*t0OldService)(void);
		s32int			LocalTime;
		u16int			TimerRate;

		u16int			NumDigi,DigiLeft,DigiPage;
		u16int			_seg *DigiList;
		u16int			DigiLastStart,DigiLastEnd;
		int			DigiPlaying;
static	int			DigiMissed,DigiLastSegment;
static	uchar *DigiNextAddr;
static	u16int			DigiNextLen;

//	SoundBlaster variables
static	int					sbNoCheck,sbNoProCheck;
static	volatile int		sbSamplePlaying;
static	u8int					sbOldIntMask = -1;
static	volatile u8int			huge *sbNextSegPtr;
static	u8int					sbDMA = 1,
								sbDMAa1 = 0x83,sbDMAa2 = 2,sbDMAa3 = 3,
								sba1Vals[] = {0x87,0x83,0,0x82},
								sba2Vals[] = {0,2,0,6},
								sba3Vals[] = {1,3,0,7};
static	s16int						sbLocation = -1,sbInterrupt = 7,sbIntVec = 0xf,
								sbIntVectors[] = {-1,-1,0xa,0xb,-1,0xd,-1,0xf,-1,-1,-1};
static	volatile u32int		sbNextSegLen;
static	volatile SampledSound	huge *sbSamples;
static	void interrupt			(*sbOldIntHand)(void);
static	u8int					sbpOldFMMix,sbpOldVOCMix;

//	SoundSource variables
		int				ssNoCheck;
		int				ssActive;
		u16int				ssControl,ssStatus,ssData;
		u8int				ssOn,ssOff;
		volatile u8int		far *ssSample;
		volatile u32int	ssLengthLeft;

//	PC Sound variables
		volatile u8int	pcLastSample,far *pcSound;
		u32int		pcLengthLeft;
		u16int			pcSoundLookup[255];

//	AdLib variables
		int			alNoCheck;
		u8int			far *alSound;
		u16int			alBlock;
		u32int		alLengthLeft;
		u32int		alTimeCount;
		Instrument		alZeroInst;

// This table maps channel numbers to carrier and modulator op cells
static	u8int			carriers[9] =  { 3, 4, 5,11,12,13,19,20,21},
						modifiers[9] = { 0, 1, 2, 8, 9,10,16,17,18},
// This table maps percussive voice numbers to op cells
						pcarriers[5] = {19,0xff,0xff,0xff,0xff},
						pmodifiers[5] = {16,17,18,20,21};

//	Sequencer variables
		int			sqActive;
static	u16int			alFXReg;
static	ActiveTrack		*tracks[sqMaxTracks],
						mytracks[sqMaxTracks];
static	u16int			sqMode,sqFadeStep;
		u16int			far *sqHack,far *sqHackPtr,sqHackLen,sqHackSeqLen;
		s32int			sqHackTime;

//	Internal routines
		void			SDL_DigitizedDone(void);

///////////////////////////////////////////////////////////////////////////
//
//	SDL_SetTimer0() - Sets system timer 0 to the specified speed
//
///////////////////////////////////////////////////////////////////////////
#pragma	argsused
static void
SDL_SetTimer0(u16int speed)
{
#ifndef TPROF	// If using Borland's profiling, don't screw with the timer
asm	pushf
asm	cli

	outportb(0x43,0x36);				// Change timer 0
	outportb(0x40,speed);
	outportb(0x40,speed >> 8);
	// Kludge to handle special case for digitized PC sounds
	if (TimerDivisor == (1192030 / (TickBase * 100)))
		TimerDivisor = (1192030 / (TickBase * 10));
	else
		TimerDivisor = speed;

asm	popf
#else
	TimerDivisor = 0x10000;
#endif
}

///////////////////////////////////////////////////////////////////////////
//
//	SDL_SetIntsPerSec() - Uses SDL_SetTimer0() to set the number of
//		interrupts generated by system timer 0 per second
//
///////////////////////////////////////////////////////////////////////////
static void
SDL_SetIntsPerSec(u16int ints)
{
	TimerRate = ints;
	SDL_SetTimer0(1192030 / ints);
}

static void
SDL_SetTimerSpeed(void)
{
	u16int	rate;
	void interrupt	(*isr)(void);

	if ((DigiMode == sds_PC) && DigiPlaying)
	{
		rate = TickBase * 100;
		isr = SDL_t0ExtremeAsmService;
	}
	else if
	(
		(MusicMode == smm_AdLib)
	||	((DigiMode == sds_SoundSource) && DigiPlaying)
	)
	{
		rate = TickBase * 10;
		isr = SDL_t0FastAsmService;
	}
	else
	{
		rate = TickBase * 2;
		isr = SDL_t0SlowAsmService;
	}

	if (rate != TimerRate)
	{
		setvect(8,isr);
		SDL_SetIntsPerSec(rate);
		TimerRate = rate;
	}
}

//
//	SoundBlaster code
//

///////////////////////////////////////////////////////////////////////////
//
//	SDL_SBStopSample() - Stops any active sampled sound and causes DMA
//		requests from the SoundBlaster to cease
//
///////////////////////////////////////////////////////////////////////////
#ifdef	_MUSE_
void
#else
static void
#endif
SDL_SBStopSample(void)
{
	u8int	is;

asm	pushf
asm	cli

	if (sbSamplePlaying)
	{
		sbSamplePlaying = false;

		sbWriteDelay();
		sbOut(sbWriteCmd,0xd0);	// Turn off DSP DMA

		is = inportb(0x21);	// Restore interrupt mask bit
		if (sbOldIntMask & (1 << sbInterrupt))
			is |= (1 << sbInterrupt);
		else
			is &= ~(1 << sbInterrupt);
		outportb(0x21,is);
	}

asm	popf
}

///////////////////////////////////////////////////////////////////////////
//
//	SDL_SBPlaySeg() - Plays a chunk of sampled sound on the SoundBlaster
//	Insures that the chunk doesn't cross a bank boundary, programs the DMA
//	 controller, and tells the SB to start doing DMA requests for DAC
//
///////////////////////////////////////////////////////////////////////////
static u32int
SDL_SBPlaySeg(volatile u8int huge *data,u32int length)
{
	u16int		datapage;
	u32int		dataofs,uselen;

	uselen = length;
	datapage = FP_SEG(data) >> 12;
	dataofs = ((FP_SEG(data) & 0xfff) << 4) + FP_OFF(data);
	if (dataofs >= 0x10000)
	{
		datapage++;
		dataofs -= 0x10000;
	}

	if (dataofs + uselen > 0x10000)
		uselen = 0x10000 - dataofs;

	uselen--;

	// Program the DMA controller
asm	pushf
asm	cli
	outportb(0x0a,sbDMA | 4);					// Mask off DMA on channel sbDMA
	outportb(0x0c,0);							// Clear byte ptr flip-flop to lower byte
	outportb(0x0b,0x49);						// Set transfer mode for D/A conv
	outportb(sbDMAa2,(u8int)dataofs);			// Give LSB of address
	outportb(sbDMAa2,(u8int)(dataofs >> 8));		// Give MSB of address
	outportb(sbDMAa1,(u8int)datapage);			// Give page of address
	outportb(sbDMAa3,(u8int)uselen);				// Give LSB of length
	outportb(sbDMAa3,(u8int)(uselen >> 8));		// Give MSB of length
	outportb(0x0a,sbDMA);						// Re-enable DMA on channel sbDMA

	// Start playing the thing
	sbWriteDelay();
	sbOut(sbWriteCmd,0x14);
	sbWriteDelay();
	sbOut(sbWriteData,(u8int)uselen);
	sbWriteDelay();
	sbOut(sbWriteData,(u8int)(uselen >> 8));
asm	popf

	return(uselen + 1);
}

///////////////////////////////////////////////////////////////////////////
//
//	SDL_SBService() - Services the SoundBlaster DMA interrupt
//
///////////////////////////////////////////////////////////////////////////
static void interrupt
SDL_SBService(void)
{
	u32int	used;

	sbIn(sbDataAvail);	// Ack interrupt to SB

	if (sbNextSegPtr)
	{
		used = SDL_SBPlaySeg(sbNextSegPtr,sbNextSegLen);
		if (sbNextSegLen <= used)
			sbNextSegPtr = nil;
		else
		{
			sbNextSegPtr += used;
			sbNextSegLen -= used;
		}
	}
	else
	{
		SDL_SBStopSample();
		SDL_DigitizedDone();
	}

	outportb(0x20,0x20);	// Ack interrupt
}

///////////////////////////////////////////////////////////////////////////
//
//	SDL_SBPlaySample() - Plays a sampled sound on the SoundBlaster. Sets up
//		DMA to play the sound
//
///////////////////////////////////////////////////////////////////////////
#ifdef	_MUSE_
void
#else
static void
#endif
SDL_SBPlaySample(u8int huge *data,u32int len)
{
	u32int	used;

	SDL_SBStopSample();

asm	pushf
asm	cli

	used = SDL_SBPlaySeg(data,len);
	if (len <= used)
		sbNextSegPtr = nil;
	else
	{
		sbNextSegPtr = data + used;
		sbNextSegLen = len - used;
	}

	// Save old interrupt status and unmask ours
	sbOldIntMask = inportb(0x21);
	outportb(0x21,sbOldIntMask & ~(1 << sbInterrupt));

	sbWriteDelay();
	sbOut(sbWriteCmd,0xd4);						// Make sure DSP DMA is enabled

	sbSamplePlaying = true;

asm	popf
}

///////////////////////////////////////////////////////////////////////////
//
//	SDL_PositionSBP() - Sets the attenuation levels for the left and right
//		channels by using the mixer chip on the SB Pro. This hits a hole in
//		the address map for normal SBs.
//
///////////////////////////////////////////////////////////////////////////
static void
SDL_PositionSBP(s16int leftpos,s16int rightpos)
{
	u8int	v;

	if (!SBProPresent)
		return;

	leftpos = 15 - leftpos;
	rightpos = 15 - rightpos;
	v = ((leftpos & 0x0f) << 4) | (rightpos & 0x0f);

asm	pushf
asm	cli

	sbOut(sbpMixerAddr,sbpmVoiceVol);
	sbOut(sbpMixerData,v);

asm	popf
}

///////////////////////////////////////////////////////////////////////////
//
//	SDL_CheckSB() - Checks to see if a SoundBlaster resides at a
//		particular I/O location
//
///////////////////////////////////////////////////////////////////////////
static int
SDL_CheckSB(s16int port)
{
	s16int	i;

	sbLocation = port << 4;		// Initialize stuff for later use

	sbOut(sbReset,true);		// Reset the SoundBlaster DSP
asm	mov	dx,0x388				// Wait >4usec
asm	in	al, dx
asm	in	al, dx
asm	in	al, dx
asm	in	al, dx
asm	in	al, dx
asm	in	al, dx
asm	in	al, dx
asm	in	al, dx
asm	in	al, dx

	sbOut(sbReset,false);		// Turn off sb DSP reset
asm	mov	dx,0x388				// Wait >100usec
asm	mov	cx,100
usecloop:
asm	in	al,dx
asm	loop usecloop

	for (i = 0;i < 100;i++)
	{
		if (sbIn(sbDataAvail) & 0x80)		// If data is available...
		{
			if (sbIn(sbReadData) == 0xaa)	// If it matches correct value
				return(true);
			else
			{
				sbLocation = -1;			// Otherwise not a SoundBlaster
				return(false);
			}
		}
	}
	sbLocation = -1;						// Retry count exceeded - fail
	return(false);
}

///////////////////////////////////////////////////////////////////////////
//
//	Checks to see if a SoundBlaster is in the system. If the port passed is
//		-1, then it scans through all possible I/O locations. If the port
//		passed is 0, then it uses the default (2). If the port is >0, then
//		it just passes it directly to SDL_CheckSB()
//
///////////////////////////////////////////////////////////////////////////
static int
SDL_DetectSoundBlaster(s16int port)
{
	s16int	i;

	if (port == 0)					// If user specifies default, use 2
		port = 2;
	if (port == -1)
	{
		if (SDL_CheckSB(2))			// Check default before scanning
			return(true);

		if (SDL_CheckSB(4))			// Check other SB Pro location before scan
			return(true);

		for (i = 1;i <= 6;i++)		// Scan through possible SB locations
		{
			if ((i == 2) || (i == 4))
				continue;

			if (SDL_CheckSB(i))		// If found at this address,
				return(true);		//	return success
		}
		return(false);				// All addresses failed, return failure
	}
	else
		return(SDL_CheckSB(port));	// User specified address or default
}

///////////////////////////////////////////////////////////////////////////
//
//	SDL_SBSetDMA() - Sets the DMA channel to be used by the SoundBlaster
//		code. Sets up sbDMA, and sbDMAa1-sbDMAa3 (used by SDL_SBPlaySeg()).
//
///////////////////////////////////////////////////////////////////////////
void
SDL_SBSetDMA(u8int channel)
{
	if (channel > 3)
		Quit("SDL_SBSetDMA() - invalid SoundBlaster DMA channel");

	sbDMA = channel;
	sbDMAa1 = sba1Vals[channel];
	sbDMAa2 = sba2Vals[channel];
	sbDMAa3 = sba3Vals[channel];
}

///////////////////////////////////////////////////////////////////////////
//
//	SDL_StartSB() - Turns on the SoundBlaster
//
///////////////////////////////////////////////////////////////////////////
static void
SDL_StartSB(void)
{
	u8int	timevalue,test;

	sbIntVec = sbIntVectors[sbInterrupt];
	if (sbIntVec < 0)
		Quit("SDL_StartSB: Illegal or unsupported interrupt number for SoundBlaster");

	sbOldIntHand = getvect(sbIntVec);	// Get old interrupt handler
	setvect(sbIntVec,SDL_SBService);	// Set mine

	sbWriteDelay();
	sbOut(sbWriteCmd,0xd1);				// Turn on DSP speaker

	// Set the SoundBlaster DAC time constant for 7KHz
	timevalue = 256 - (1000000 / 7000);
	sbWriteDelay();
	sbOut(sbWriteCmd,0x40);
	sbWriteDelay();
	sbOut(sbWriteData,timevalue);

	SBProPresent = false;
	if (sbNoProCheck)
		return;

	// Check to see if this is a SB Pro
	sbOut(sbpMixerAddr,sbpmFMVol);
	sbpOldFMMix = sbIn(sbpMixerData);
	sbOut(sbpMixerData,0xbb);
	test = sbIn(sbpMixerData);
	if (test == 0xbb)
	{
		// Boost FM output levels to be equivilent with digitized output
		sbOut(sbpMixerData,0xff);
		test = sbIn(sbpMixerData);
		if (test == 0xff)
		{
			SBProPresent = true;

			// Save old Voice output levels (SB Pro)
			sbOut(sbpMixerAddr,sbpmVoiceVol);
			sbpOldVOCMix = sbIn(sbpMixerData);

			// Turn SB Pro stereo DAC off
			sbOut(sbpMixerAddr,sbpmControl);
			sbOut(sbpMixerData,0);				// 0=off,2=on
		}
	}
}

///////////////////////////////////////////////////////////////////////////
//
//	SDL_ShutSB() - Turns off the SoundBlaster
//
///////////////////////////////////////////////////////////////////////////
static void
SDL_ShutSB(void)
{
	SDL_SBStopSample();

	if (SBProPresent)
	{
		// Restore FM output levels (SB Pro)
		sbOut(sbpMixerAddr,sbpmFMVol);
		sbOut(sbpMixerData,sbpOldFMMix);

		// Restore Voice output levels (SB Pro)
		sbOut(sbpMixerAddr,sbpmVoiceVol);
		sbOut(sbpMixerData,sbpOldVOCMix);
	}

	setvect(sbIntVec,sbOldIntHand);		// Set vector back
}

//	Sound Source Code

///////////////////////////////////////////////////////////////////////////
//
//	SDL_SSStopSample() - Stops a sample playing on the Sound Source
//
///////////////////////////////////////////////////////////////////////////
#ifdef	_MUSE_
void
#else
static void
#endif
SDL_SSStopSample(void)
{
asm	pushf
asm	cli

	(s32int)ssSample = 0;

asm	popf
}

///////////////////////////////////////////////////////////////////////////
//
//	SDL_SSService() - Handles playing the next sample on the Sound Source
//
///////////////////////////////////////////////////////////////////////////
static void
SDL_SSService(void)
{
	int	gotit;
	u8int	v;

	while (ssSample)
	{
	asm	mov		dx,[ssStatus]	// Check to see if FIFO is currently empty
	asm	in		al,dx
	asm	test	al,0x40
	asm	jnz		done			// Nope - don't push any more data out

		v = *ssSample++;
		if (!(--ssLengthLeft))
		{
			(s32int)ssSample = 0;
			SDL_DigitizedDone();
		}

	asm	mov		dx,[ssData]		// Pump the value out
	asm	mov		al,[v]
	asm	out		dx,al

	asm	mov		dx,[ssControl]	// Pulse printer select
	asm	mov		al,[ssOff]
	asm	out		dx,al
	asm	push	ax
	asm	pop		ax
	asm	mov		al,[ssOn]
	asm	out		dx,al

	asm	push	ax				// Delay a short while
	asm	pop		ax
	asm	push	ax
	asm	pop		ax
	}
done:;
}

///////////////////////////////////////////////////////////////////////////
//
//	SDL_SSPlaySample() - Plays the specified sample on the Sound Source
//
///////////////////////////////////////////////////////////////////////////
#ifdef	_MUSE_
void
#else
static void
#endif
SDL_SSPlaySample(u8int huge *data,u32int len)
{
asm	pushf
asm	cli

	ssLengthLeft = len;
	ssSample = (volatile u8int far *)data;

asm	popf
}

///////////////////////////////////////////////////////////////////////////
//
//	SDL_StartSS() - Sets up for and turns on the Sound Source
//
///////////////////////////////////////////////////////////////////////////
static void
SDL_StartSS(void)
{
	if (ssPort == 3)
		ssControl = 0x27a;	// If using LPT3
	else if (ssPort == 2)
		ssControl = 0x37a;	// If using LPT2
	else
		ssControl = 0x3be;	// If using LPT1
	ssStatus = ssControl - 1;
	ssData = ssStatus - 1;

	ssOn = 0x04;
	if (ssIsTandy)
		ssOff = 0x0e;				// Tandy wierdness
	else
		ssOff = 0x0c;				// For normal machines

	outportb(ssControl,ssOn);		// Enable SS
}

///////////////////////////////////////////////////////////////////////////
//
//	SDL_ShutSS() - Turns off the Sound Source
//
///////////////////////////////////////////////////////////////////////////
static void
SDL_ShutSS(void)
{
	outportb(ssControl,ssOff);
}

///////////////////////////////////////////////////////////////////////////
//
//	SDL_CheckSS() - Checks to see if a Sound Source is present at the
//		location specified by the sound source variables
//
///////////////////////////////////////////////////////////////////////////
static int
SDL_CheckSS(void)
{
	int		present = false;
	u32int	lasttime;

	// Turn the Sound Source on and wait awhile (4 ticks)
	SDL_StartSS();

	lasttime = TimeCount;
	while (TimeCount < lasttime + 4)
		;

asm	mov		dx,[ssStatus]	// Check to see if FIFO is currently empty
asm	in		al,dx
asm	test	al,0x40
asm	jnz		checkdone		// Nope - Sound Source not here

asm	mov		cx,32			// Force FIFO overflow (FIFO is 16 bytes)
outloop:
asm	mov		dx,[ssData]		// Pump a neutral value out
asm	mov		al,0x80
asm	out		dx,al

asm	mov		dx,[ssControl]	// Pulse printer select
asm	mov		al,[ssOff]
asm	out		dx,al
asm	push	ax
asm	pop		ax
asm	mov		al,[ssOn]
asm	out		dx,al

asm	push	ax				// Delay a short while before we do this again
asm	pop		ax
asm	push	ax
asm	pop		ax

asm	loop	outloop

asm	mov		dx,[ssStatus]	// Is FIFO overflowed now?
asm	in		al,dx
asm	test	al,0x40
asm	jz		checkdone		// Nope, still not - Sound Source not here

	present = true;			// Yes - it's here!

checkdone:
	SDL_ShutSS();
	return(present);
}

static int
SDL_DetectSoundSource(void)
{
	for (ssPort = 1;ssPort <= 3;ssPort++)
		if (SDL_CheckSS())
			return(true);
	return(false);
}

//
//	PC Sound code
//

///////////////////////////////////////////////////////////////////////////
//
//	SDL_PCPlaySample() - Plays the specified sample on the PC speaker
//
///////////////////////////////////////////////////////////////////////////
#ifdef	_MUSE_
void
#else
static void
#endif
SDL_PCPlaySample(u8int huge *data,u32int len)
{
asm	pushf
asm	cli

	SDL_IndicatePC(true);

	pcLengthLeft = len;
	pcSound = (volatile u8int far *)data;

asm	popf
}

///////////////////////////////////////////////////////////////////////////
//
//	SDL_PCStopSample() - Stops a sample playing on the PC speaker
//
///////////////////////////////////////////////////////////////////////////
#ifdef	_MUSE_
void
#else
static void
#endif
SDL_PCStopSample(void)
{
asm	pushf
asm	cli

	(s32int)pcSound = 0;

	SDL_IndicatePC(false);

asm	in	al,0x61		  	// Turn the speaker off
asm	and	al,0xfd			// ~2
asm	out	0x61,al

asm	popf
}

///////////////////////////////////////////////////////////////////////////
//
//	SDL_PCPlaySound() - Plays the specified sound on the PC speaker
//
///////////////////////////////////////////////////////////////////////////
#ifdef	_MUSE_
void
#else
static void
#endif
SDL_PCPlaySound(PCSound far *sound)
{
asm	pushf
asm	cli

	pcLastSample = -1;
	pcLengthLeft = sound->common.length;
	pcSound = sound->data;

asm	popf
}

///////////////////////////////////////////////////////////////////////////
//
//	SDL_PCStopSound() - Stops the current sound playing on the PC Speaker
//
///////////////////////////////////////////////////////////////////////////
#ifdef	_MUSE_
void
#else
static void
#endif
SDL_PCStopSound(void)
{
asm	pushf
asm	cli

	(s32int)pcSound = 0;

asm	in	al,0x61		  	// Turn the speaker off
asm	and	al,0xfd			// ~2
asm	out	0x61,al

asm	popf
}

#if 0
///////////////////////////////////////////////////////////////////////////
//
//	SDL_PCService() - Handles playing the next sample in a PC sound
//
///////////////////////////////////////////////////////////////////////////
static void
SDL_PCService(void)
{
	u8int	s;
	u16int	t;

	if (pcSound)
	{
		s = *pcSound++;
		if (s != pcLastSample)
		{
		asm	pushf
		asm	cli

			pcLastSample = s;
			if (s)					// We have a frequency!
			{
				t = pcSoundLookup[s];
			asm	mov	bx,[t]

			asm	mov	al,0xb6			// Write to channel 2 (speaker) timer
			asm	out	43h,al
			asm	mov	al,bl
			asm	out	42h,al			// Low byte
			asm	mov	al,bh
			asm	out	42h,al			// High byte

			asm	in	al,0x61			// Turn the speaker & gate on
			asm	or	al,3
			asm	out	0x61,al
			}
			else					// Time for some silence
			{
			asm	in	al,0x61		  	// Turn the speaker & gate off
			asm	and	al,0xfc			// ~3
			asm	out	0x61,al
			}

		asm	popf
		}

		if (!(--pcLengthLeft))
		{
			SDL_PCStopSound();
			SDL_SoundFinished();
		}
	}
}
#endif

///////////////////////////////////////////////////////////////////////////
//
//	SDL_ShutPC() - Turns off the pc speaker
//
///////////////////////////////////////////////////////////////////////////
static void
SDL_ShutPC(void)
{
asm	pushf
asm	cli

	pcSound = 0;

asm	in	al,0x61		  	// Turn the speaker & gate off
asm	and	al,0xfc			// ~3
asm	out	0x61,al

asm	popf
}

//
//	Stuff for digitized sounds
//
uchar *
SDL_LoadDigiSegment(u16int page)
{
	uchar *addr;

#if 0	// for debugging
asm	mov	dx,STATUS_REGISTER_1
asm	in	al,dx
asm	mov	dx,ATR_INDEX
asm	mov	al,ATR_OVERSCAN
asm	out	dx,al
asm	mov	al,10	// bright green
asm	out	dx,al
#endif

	addr = PM_GetSoundPage(page);
	PM_SetPageLock(PMSoundStart + page,pml_Locked);

#if 0	// for debugging
asm	mov	dx,STATUS_REGISTER_1
asm	in	al,dx
asm	mov	dx,ATR_INDEX
asm	mov	al,ATR_OVERSCAN
asm	out	dx,al
asm	mov	al,3	// blue
asm	out	dx,al
asm	mov	al,0x20	// normal
asm	out	dx,al
#endif

	return(addr);
}

void
SDL_PlayDigiSegment(uchar *addr,u16int len)
{
	switch (DigiMode)
	{
	case sds_PC:
    	SDL_PCPlaySample(addr,len);
		break;
	case sds_SoundSource:
		SDL_SSPlaySample(addr,len);
		break;
	case sds_SoundBlaster:
		SDL_SBPlaySample(addr,len);
		break;
	}
}

void
SD_StopDigitized(void)
{
	s16int	i;

asm	pushf
asm	cli

	DigiLeft = 0;
	DigiNextAddr = nil;
	DigiNextLen = 0;
	DigiMissed = false;
	DigiPlaying = false;
	DigiNumber = DigiPriority = 0;
	SoundPositioned = false;
	if ((DigiMode == sds_PC) && (SoundMode == sdm_PC))
		SDL_SoundFinished();

	switch (DigiMode)
	{
	case sds_PC:
		SDL_PCStopSample();
		break;
	case sds_SoundSource:
		SDL_SSStopSample();
		break;
	case sds_SoundBlaster:
		SDL_SBStopSample();
		break;
	}

asm	popf

	for (i = DigiLastStart;i < DigiLastEnd;i++)
		PM_SetPageLock(i + PMSoundStart,pml_Unlocked);
	DigiLastStart = 1;
	DigiLastEnd = 0;
}

void
SD_Poll(void)
{
	if (DigiLeft && !DigiNextAddr)
	{
		DigiNextLen = (DigiLeft >= PMPageSize)? PMPageSize : (DigiLeft % PMPageSize);
		DigiLeft -= DigiNextLen;
		if (!DigiLeft)
			DigiLastSegment = true;
		DigiNextAddr = SDL_LoadDigiSegment(DigiPage++);
	}
	if (DigiMissed && DigiNextAddr)
	{
		SDL_PlayDigiSegment(DigiNextAddr,DigiNextLen);
		DigiNextAddr = nil;
		DigiMissed = false;
		if (DigiLastSegment)
		{
			DigiPlaying = false;
			DigiLastSegment = false;
		}
	}
	SDL_SetTimerSpeed();
}

void
SD_SetPosition(s16int leftpos,s16int rightpos)
{
	if
	(
		(leftpos < 0)
	||	(leftpos > 15)
	||	(rightpos < 0)
	||	(rightpos > 15)
	||	((leftpos == 15) && (rightpos == 15))
	)
		Quit("SD_SetPosition: Illegal position");

	switch (DigiMode)
	{
	case sds_SoundBlaster:
		SDL_PositionSBP(leftpos,rightpos);
		break;
	}
}

void
SD_PlayDigitized(u16int which,s16int leftpos,s16int rightpos)
{
	u16int	len;
	uchar *addr;

	if (!DigiMode)
		return;

	SD_StopDigitized();
	if (which >= NumDigi)
		Quit("SD_PlayDigitized: bad sound number");

	SD_SetPosition(leftpos,rightpos);

	DigiPage = DigiList[(which * 2) + 0];
	DigiLeft = DigiList[(which * 2) + 1];

	DigiLastStart = DigiPage;
	DigiLastEnd = DigiPage + ((DigiLeft + (PMPageSize - 1)) / PMPageSize);

	len = (DigiLeft >= PMPageSize)? PMPageSize : (DigiLeft % PMPageSize);
	addr = SDL_LoadDigiSegment(DigiPage++);

	DigiPlaying = true;
	DigiLastSegment = false;

	SDL_PlayDigiSegment(addr,len);
	DigiLeft -= len;
	if (!DigiLeft)
		DigiLastSegment = true;

	SD_Poll();
}

void
SDL_DigitizedDone(void)
{
	if (DigiNextAddr)
	{
		SDL_PlayDigiSegment(DigiNextAddr,DigiNextLen);
		DigiNextAddr = nil;
		DigiMissed = false;
	}
	else
	{
		if (DigiLastSegment)
		{
			DigiPlaying = false;
			DigiLastSegment = false;
			if ((DigiMode == sds_PC) && (SoundMode == sdm_PC))
			{
				SDL_SoundFinished();
			}
			else
				DigiNumber = DigiPriority = 0;
			SoundPositioned = false;
		}
		else
			DigiMissed = true;
	}
}

void
SD_SetDigiDevice(SDSMode mode)
{
	int	devicenotpresent;

	if (mode == DigiMode)
		return;

	SD_StopDigitized();

	devicenotpresent = false;
	switch (mode)
	{
	case sds_SoundBlaster:
		if (!SoundBlasterPresent)
		{
			if (SoundSourcePresent)
				mode = sds_SoundSource;
			else
				devicenotpresent = true;
		}
		break;
	case sds_SoundSource:
		if (!SoundSourcePresent)
			devicenotpresent = true;
		break;
	}

	if (!devicenotpresent)
	{
		if (DigiMode == sds_SoundSource)
			SDL_ShutSS();

		DigiMode = mode;

		if (mode == sds_SoundSource)
			SDL_StartSS();

		SDL_SetTimerSpeed();
	}
}

void
SDL_SetupDigi(void)
{
	uchar *list;
	u16int	far *p,
			pg;
	s16int		i;

	PM_UnlockMainMem();
	MM_GetPtr(&list,PMPageSize);
	PM_CheckMainMem();
	p = (u16int far *)MK_FP(PM_GetPage(ChunksInFile - 1),0);
	_fmemcpy((void far *)list,(void far *)p,PMPageSize);
	pg = PMSoundStart;
	for (i = 0;i < PMPageSize / (sizeof(u16int) * 2);i++,p += 2)
	{
		if (pg >= ChunksInFile - 1)
			break;
		pg += (p[1] + (PMPageSize - 1)) / PMPageSize;
	}
	PM_UnlockMainMem();
	MM_GetPtr((uchar **)&DigiList,i * sizeof(u16int) * 2);
	_fmemcpy((void far *)DigiList,(void far *)list,i * sizeof(u16int) * 2);
	MM_FreePtr(&list);
	NumDigi = i;

	for (i = 0;i < LASTSOUND;i++)
		DigiMap[i] = -1;
}

// 	AdLib Code

///////////////////////////////////////////////////////////////////////////
//
//	alOut(n,b) - Puts b in AdLib card register n
//
///////////////////////////////////////////////////////////////////////////
void
alOut(u8int n,u8int b)
{
asm	pushf
asm	cli

asm	mov	dx,0x388
asm	mov	al,[n]
asm	out	dx,al
asm	in	al,dx
asm	in	al,dx
asm	in	al,dx
asm	in	al,dx
asm	in	al,dx
asm	in	al,dx
asm	inc	dx
asm	mov	al,[b]
asm	out	dx,al

asm	popf

asm	dec	dx
asm	in	al,dx
asm	in	al,dx
asm	in	al,dx
asm	in	al,dx
asm	in	al,dx
asm	in	al,dx
asm	in	al,dx
asm	in	al,dx
asm	in	al,dx
asm	in	al,dx

asm	in	al,dx
asm	in	al,dx
asm	in	al,dx
asm	in	al,dx
asm	in	al,dx
asm	in	al,dx
asm	in	al,dx
asm	in	al,dx
asm	in	al,dx
asm	in	al,dx

asm	in	al,dx
asm	in	al,dx
asm	in	al,dx
asm	in	al,dx
asm	in	al,dx
asm	in	al,dx
asm	in	al,dx
asm	in	al,dx
asm	in	al,dx
asm	in	al,dx

asm	in	al,dx
asm	in	al,dx
asm	in	al,dx
asm	in	al,dx
asm	in	al,dx
}

#if 0
///////////////////////////////////////////////////////////////////////////
//
//	SDL_SetInstrument() - Puts an instrument into a generator
//
///////////////////////////////////////////////////////////////////////////
static void
SDL_SetInstrument(s16int track,s16int which,Instrument far *inst,int percussive)
{
	u8int		c,m;

	if (percussive)
	{
		c = pcarriers[which];
		m = pmodifiers[which];
	}
	else
	{
		c = carriers[which];
		m = modifiers[which];
	}

	tracks[track - 1]->inst = *inst;
	tracks[track - 1]->percussive = percussive;

	alOut(m + alChar,inst->mChar);
	alOut(m + alScale,inst->mScale);
	alOut(m + alAttack,inst->mAttack);
	alOut(m + alSus,inst->mSus);
	alOut(m + alWave,inst->mWave);

	// Most percussive instruments only use one cell
	if (c != 0xff)
	{
		alOut(c + alChar,inst->cChar);
		alOut(c + alScale,inst->cScale);
		alOut(c + alAttack,inst->cAttack);
		alOut(c + alSus,inst->cSus);
		alOut(c + alWave,inst->cWave);
	}

	alOut(which + alFeedCon,inst->nConn);	// DEBUG - I think this is right
}
#endif

///////////////////////////////////////////////////////////////////////////
//
//	SDL_ALStopSound() - Turns off any sound effects playing through the
//		AdLib card
//
///////////////////////////////////////////////////////////////////////////
#ifdef	_MUSE_
void
#else
static void
#endif
SDL_ALStopSound(void)
{
asm	pushf
asm	cli

	(s32int)alSound = 0;
	alOut(alFreqH + 0,0);

asm	popf
}

static void
SDL_AlSetFXInst(Instrument far *inst)
{
	u8int		c,m;

	m = modifiers[0];
	c = carriers[0];
	alOut(m + alChar,inst->mChar);
	alOut(m + alScale,inst->mScale);
	alOut(m + alAttack,inst->mAttack);
	alOut(m + alSus,inst->mSus);
	alOut(m + alWave,inst->mWave);
	alOut(c + alChar,inst->cChar);
	alOut(c + alScale,inst->cScale);
	alOut(c + alAttack,inst->cAttack);
	alOut(c + alSus,inst->cSus);
	alOut(c + alWave,inst->cWave);

	// Note: Switch commenting on these lines for old MUSE compatibility
//	alOut(alFeedCon,inst->nConn);
	alOut(alFeedCon,0);
}

///////////////////////////////////////////////////////////////////////////
//
//	SDL_ALPlaySound() - Plays the specified sound on the AdLib card
//
///////////////////////////////////////////////////////////////////////////
#ifdef	_MUSE_
void
#else
static void
#endif
SDL_ALPlaySound(AdLibSound far *sound)
{
	Instrument	far *inst;
	u8int		huge *data;

	SDL_ALStopSound();

asm	pushf
asm	cli

	alLengthLeft = sound->common.length;
	data = sound->data;
	data++;
	data--;
	alSound = (u8int far *)data;
	alBlock = ((sound->block & 7) << 2) | 0x20;
	inst = &sound->inst;

	if (!(inst->mSus | inst->cSus))
	{
	asm	popf
		Quit("SDL_ALPlaySound() - Bad instrument");
	}

	SDL_AlSetFXInst(&alZeroInst);	// DEBUG
	SDL_AlSetFXInst(inst);

asm	popf
}

#if 0
///////////////////////////////////////////////////////////////////////////
//
// 	SDL_ALSoundService() - Plays the next sample out through the AdLib card
//
///////////////////////////////////////////////////////////////////////////
//static void
void
SDL_ALSoundService(void)
{
	u8int	s;

	if (alSound)
	{
		s = *alSound++;
		if (!s)
			alOut(alFreqH + 0,0);
		else
		{
			alOut(alFreqL + 0,s);
			alOut(alFreqH + 0,alBlock);
		}

		if (!(--alLengthLeft))
		{
			(s32int)alSound = 0;
			alOut(alFreqH + 0,0);
			SDL_SoundFinished();
		}
	}
}
#endif

#if 0
void
SDL_ALService(void)
{
	u8int	a,v;
	u16int	w;

	if (!sqActive)
		return;

	while (sqHackLen && (sqHackTime <= alTimeCount))
	{
		w = *sqHackPtr++;
		sqHackTime = alTimeCount + *sqHackPtr++;
	asm	mov	dx,[w]
	asm	mov	[a],dl
	asm	mov	[v],dh
		alOut(a,v);
		sqHackLen -= 4;
	}
	alTimeCount++;
	if (!sqHackLen)
	{
		sqHackPtr = (u16int far *)sqHack;
		sqHackLen = sqHackSeqLen;
		alTimeCount = sqHackTime = 0;
	}
}
#endif

///////////////////////////////////////////////////////////////////////////
//
//	SDL_ShutAL() - Shuts down the AdLib card for sound effects
//
///////////////////////////////////////////////////////////////////////////
static void
SDL_ShutAL(void)
{
asm	pushf
asm	cli

	alOut(alEffects,0);
	alOut(alFreqH + 0,0);
	SDL_AlSetFXInst(&alZeroInst);
	alSound = 0;

asm	popf
}

///////////////////////////////////////////////////////////////////////////
//
//	SDL_CleanAL() - Totally shuts down the AdLib card
//
///////////////////////////////////////////////////////////////////////////
static void
SDL_CleanAL(void)
{
	s16int	i;

asm	pushf
asm	cli

	alOut(alEffects,0);
	for (i = 1;i < 0xf5;i++)
		alOut(i,0);

asm	popf
}

///////////////////////////////////////////////////////////////////////////
//
//	SDL_StartAL() - Starts up the AdLib card for sound effects
//
///////////////////////////////////////////////////////////////////////////
static void
SDL_StartAL(void)
{
	alFXReg = 0;
	alOut(alEffects,alFXReg);
	SDL_AlSetFXInst(&alZeroInst);
}

///////////////////////////////////////////////////////////////////////////
//
//	SDL_DetectAdLib() - Determines if there's an AdLib (or SoundBlaster
//		emulating an AdLib) present
//
///////////////////////////////////////////////////////////////////////////
static int
SDL_DetectAdLib(void)
{
	u8int	status1,status2;
	s16int		i;

	alOut(4,0x60);	// Reset T1 & T2
	alOut(4,0x80);	// Reset IRQ
	status1 = readstat();
	alOut(2,0xff);	// Set timer 1
	alOut(4,0x21);	// Start timer 1
#if 0
	SDL_Delay(TimerDelay100);
#else
asm	mov	dx,0x388
asm	mov	cx,100
usecloop:
asm	in	al,dx
asm	loop usecloop
#endif

	status2 = readstat();
	alOut(4,0x60);
	alOut(4,0x80);

	if (((status1 & 0xe0) == 0x00) && ((status2 & 0xe0) == 0xc0))
	{
		for (i = 1;i <= 0xf5;i++)	// Zero all the registers
			alOut(i,0);

		alOut(1,0x20);	// Set WSE=1
		alOut(8,0);		// Set CSM=0 & SEL=0

		return(true);
	}
	else
		return(false);
}

#if 0
///////////////////////////////////////////////////////////////////////////
//
//	SDL_t0Service() - My timer 0 ISR which handles the different timings and
//		dispatches to whatever other routines are appropriate
//
///////////////////////////////////////////////////////////////////////////
static void interrupt
SDL_t0Service(void)
{
static	u16int	count = 1;

#if 1	// for debugging
asm	mov	dx,STATUS_REGISTER_1
asm	in	al,dx
asm	mov	dx,ATR_INDEX
asm	mov	al,ATR_OVERSCAN
asm	out	dx,al
asm	mov	al,4	// red
asm	out	dx,al
#endif

	HackCount++;

	if ((MusicMode == smm_AdLib) || (DigiMode == sds_SoundSource))
	{
		SDL_ALService();
		SDL_SSService();
//		if (!(++count & 7))
		if (!(++count % 10))
		{
			LocalTime++;
			TimeCount++;
			if (SoundUserHook)
				SoundUserHook();
		}
//		if (!(count & 3))
		if (!(count % 5))
		{
			switch (SoundMode)
			{
			case sdm_PC:
				SDL_PCService();
				break;
			case sdm_AdLib:
				SDL_ALSoundService();
				break;
			}
		}
	}
	else
	{
		if (!(++count & 1))
		{
			LocalTime++;
			TimeCount++;
			if (SoundUserHook)
				SoundUserHook();
		}
		switch (SoundMode)
		{
		case sdm_PC:
			SDL_PCService();
			break;
		case sdm_AdLib:
			SDL_ALSoundService();
			break;
		}
	}

asm	mov	ax,[WORD PTR TimerCount]
asm	add	ax,[WORD PTR TimerDivisor]
asm	mov	[WORD PTR TimerCount],ax
asm	jnc	myack
	t0OldService();			// If we overflow a u16int, time to call old long handler
asm	jmp	olddone
myack:;
	outportb(0x20,0x20);	// Ack the interrupt
olddone:;

#if 1	// for debugging
asm	mov	dx,STATUS_REGISTER_1
asm	in	al,dx
asm	mov	dx,ATR_INDEX
asm	mov	al,ATR_OVERSCAN
asm	out	dx,al
asm	mov	al,3	// blue
asm	out	dx,al
asm	mov	al,0x20	// normal
asm	out	dx,al
#endif
}
#endif

////////////////////////////////////////////////////////////////////////////
//
//	SDL_ShutDevice() - turns off whatever device was being used for sound fx
//
////////////////////////////////////////////////////////////////////////////
static void
SDL_ShutDevice(void)
{
	switch (SoundMode)
	{
	case sdm_PC:
		SDL_ShutPC();
		break;
	case sdm_AdLib:
		SDL_ShutAL();
		break;
	}
	SoundMode = sdm_Off;
}

///////////////////////////////////////////////////////////////////////////
//
//	SDL_CleanDevice() - totally shuts down all sound devices
//
///////////////////////////////////////////////////////////////////////////
static void
SDL_CleanDevice(void)
{
	if ((SoundMode == sdm_AdLib) || (MusicMode == smm_AdLib))
		SDL_CleanAL();
}

///////////////////////////////////////////////////////////////////////////
//
//	SDL_StartDevice() - turns on whatever device is to be used for sound fx
//
///////////////////////////////////////////////////////////////////////////
static void
SDL_StartDevice(void)
{
	switch (SoundMode)
	{
	case sdm_AdLib:
		SDL_StartAL();
		break;
	}
	SoundNumber = SoundPriority = 0;
}

//	Public routines

///////////////////////////////////////////////////////////////////////////
//
//	SD_SetSoundMode() - Sets which sound hardware to use for sound effects
//
///////////////////////////////////////////////////////////////////////////
int
SD_SetSoundMode(SDMode mode)
{
	int	result = false;
	u16int	tableoffset;

	SD_StopSound();

#ifndef	_MUSE_
	if ((mode == sdm_AdLib) && !AdLibPresent)
		mode = sdm_PC;

	switch (mode)
	{
	case sdm_Off:
		NeedsDigitized = false;
		result = true;
		break;
	case sdm_PC:
		tableoffset = STARTPCSOUNDS;
		NeedsDigitized = false;
		result = true;
		break;
	case sdm_AdLib:
		if (AdLibPresent)
		{
			tableoffset = STARTADLIBSOUNDS;
			NeedsDigitized = false;
			result = true;
		}
		break;
	}
#else
	result = true;
#endif

	if (result && (mode != SoundMode))
	{
		SDL_ShutDevice();
		SoundMode = mode;
#ifndef	_MUSE_
		SoundTable = (u16int *)(&audiosegs[tableoffset]);
#endif
		SDL_StartDevice();
	}

	SDL_SetTimerSpeed();

	return(result);
}

///////////////////////////////////////////////////////////////////////////
//
//	SD_SetMusicMode() - sets the device to use for background music
//
///////////////////////////////////////////////////////////////////////////
int
SD_SetMusicMode(SMMode mode)
{
	int	result = false;

	SD_FadeOutMusic();
	while (SD_MusicPlaying())
		;

	switch (mode)
	{
	case smm_Off:
		NeedsMusic = false;
		result = true;
		break;
	case smm_AdLib:
		if (AdLibPresent)
		{
			NeedsMusic = true;
			result = true;
		}
		break;
	}

	if (result)
		MusicMode = mode;

	SDL_SetTimerSpeed();

	return(result);
}

///////////////////////////////////////////////////////////////////////////
//
//	SD_Startup() - starts up the Sound Mgr
//		Detects all additional sound hardware and installs my ISR
//
///////////////////////////////////////////////////////////////////////////
void
SD_Startup(void)
{
	s16int	i;

	if (SD_Started)
		return;

	SDL_SetDS();

	ssIsTandy = false;
	ssNoCheck = false;
	alNoCheck = false;
	sbNoCheck = false;
	sbNoProCheck = false;
#ifndef	_MUSE_
	for (i = 1;i < _argc;i++)
	{
		switch (US_CheckParm(_argv[i],ParmStrings))
		{
		case 0:						// No AdLib detection
			alNoCheck = true;
			break;
		case 1:						// No SoundBlaster detection
			sbNoCheck = true;
			break;
		case 2:						// No SoundBlaster Pro detection
			sbNoProCheck = true;
			break;
		case 3:
			ssNoCheck = true;		// No Sound Source detection
			break;
		case 4:						// Tandy Sound Source handling
			ssIsTandy = true;
			break;
		case 5:						// Sound Source present at LPT1
			ssPort = 1;
			ssNoCheck = SoundSourcePresent = true;
			break;
		case 6:                     // Sound Source present at LPT2
			ssPort = 2;
			ssNoCheck = SoundSourcePresent = true;
			break;
		case 7:                     // Sound Source present at LPT3
			ssPort = 3;
			ssNoCheck = SoundSourcePresent = true;
			break;
		}
	}
#endif

	SoundUserHook = 0;

	t0OldService = getvect(8);	// Get old timer 0 ISR

	LocalTime = TimeCount = alTimeCount = 0;

	SD_SetSoundMode(sdm_Off);
	SD_SetMusicMode(smm_Off);

	if (!ssNoCheck)
		SoundSourcePresent = SDL_DetectSoundSource();

	if (!alNoCheck)
	{
		AdLibPresent = SDL_DetectAdLib();
		if (AdLibPresent && !sbNoCheck)
		{
			s16int port = -1;
			char *env = getenv("BLASTER");
			if (env)
			{
				s32int temp;
				while (*env)
				{
					while (isspace(*env))
						env++;

					switch (toupper(*env))
					{
					case 'A':
						temp = strtol(env + 1,&env,16);
						if
						(
							(temp >= 0x210)
						&&	(temp <= 0x260)
						&&	(!(temp & 0x00f))
						)
							port = (temp - 0x200) >> 4;
						else
							Quit("SD_Startup: Unsupported address value in BLASTER");
						break;
					case 'I':
						temp = strtol(env + 1,&env,10);
						if
						(
							(temp >= 0)
						&&	(temp <= 10)
						&&	(sbIntVectors[temp] != -1)
						)
						{
							sbInterrupt = temp;
							sbIntVec = sbIntVectors[sbInterrupt];
						}
						else
							Quit("SD_Startup: Unsupported interrupt value in BLASTER");
						break;
					case 'D':
						temp = strtol(env + 1,&env,10);
						if ((temp == 0) || (temp == 1) || (temp == 3))
							SDL_SBSetDMA(temp);
						else
							Quit("SD_Startup: Unsupported DMA value in BLASTER");
						break;
					default:
						while (isspace(*env))
							env++;
						while (*env && !isspace(*env))
							env++;
						break;
					}
				}
			}
			SoundBlasterPresent = SDL_DetectSoundBlaster(port);
		}
	}

	for (i = 0;i < 255;i++)
		pcSoundLookup[i] = i * 60;

	if (SoundBlasterPresent)
		SDL_StartSB();

	SDL_SetupDigi();

	SD_Started = true;
}

///////////////////////////////////////////////////////////////////////////
//
//	SD_Default() - Sets up the default behaviour for the Sound Mgr whether
//		the config file was present or not.
//
///////////////////////////////////////////////////////////////////////////
void
SD_Default(int gotit,SDMode sd,SMMode sm)
{
	int	gotsd,gotsm;

	gotsd = gotsm = gotit;

	if (gotsd)	// Make sure requested sound hardware is available
	{
		switch (sd)
		{
		case sdm_AdLib:
			gotsd = AdLibPresent;
			break;
		}
	}
	if (!gotsd)
	{
		if (AdLibPresent)
			sd = sdm_AdLib;
		else
			sd = sdm_PC;
	}
	if (sd != SoundMode)
		SD_SetSoundMode(sd);


	if (gotsm)	// Make sure requested music hardware is available
	{
		switch (sm)
		{
		case sdm_AdLib:
			gotsm = AdLibPresent;
			break;
		}
	}
	if (!gotsm)
	{
		if (AdLibPresent)
			sm = smm_AdLib;
	}
	if (sm != MusicMode)
		SD_SetMusicMode(sm);
}

///////////////////////////////////////////////////////////////////////////
//
//	SD_Shutdown() - shuts down the Sound Mgr
//		Removes sound ISR and turns off whatever sound hardware was active
//
///////////////////////////////////////////////////////////////////////////
void
SD_Shutdown(void)
{
	if (!SD_Started)
		return;

	SD_MusicOff();
	SD_StopSound();
	SDL_ShutDevice();
	SDL_CleanDevice();

	if (SoundBlasterPresent)
		SDL_ShutSB();

	if (SoundSourcePresent)
		SDL_ShutSS();

	asm	pushf
	asm	cli

	SDL_SetTimer0(0);

	setvect(8,t0OldService);

	asm	popf

	SD_Started = false;
}

///////////////////////////////////////////////////////////////////////////
//
//	SD_SetUserHook() - sets the routine that the Sound Mgr calls every 1/70th
//		of a second from its timer 0 ISR
//
///////////////////////////////////////////////////////////////////////////
void
SD_SetUserHook(void (* hook)(void))
{
	SoundUserHook = hook;
}

///////////////////////////////////////////////////////////////////////////
//
//	SD_PositionSound() - Sets up a stereo imaging location for the next
//		sound to be played. Each channel ranges from 0 to 15.
//
///////////////////////////////////////////////////////////////////////////
void
SD_PositionSound(s16int leftvol,s16int rightvol)
{
	LeftPosition = leftvol;
	RightPosition = rightvol;
	nextsoundpos = true;
}

///////////////////////////////////////////////////////////////////////////
//
//	SD_PlaySound() - plays the specified sound on the appropriate hardware
//
///////////////////////////////////////////////////////////////////////////
int
SD_PlaySound(soundnames sound)
{
	int		ispos;
	SoundCommon	far *s;
	s16int	lp,rp;

	lp = LeftPosition;
	rp = RightPosition;
	LeftPosition = 0;
	RightPosition = 0;

	ispos = nextsoundpos;
	nextsoundpos = false;

	if (sound == -1)
		return(false);

	s = MK_FP(SoundTable[sound],0);
	if ((SoundMode != sdm_Off) && !s)
		Quit("SD_PlaySound() - Uncached sound");

	if ((DigiMode != sds_Off) && (DigiMap[sound] != -1))
	{
		if ((DigiMode == sds_PC) && (SoundMode == sdm_PC))
		{
			if (s->priority < SoundPriority)
				return(false);

			SDL_PCStopSound();

			SD_PlayDigitized(DigiMap[sound],lp,rp);
			SoundPositioned = ispos;
			SoundNumber = sound;
			SoundPriority = s->priority;
		}
		else
		{
		asm	pushf
		asm	cli
			if (DigiPriority && !DigiNumber)
			{
			asm	popf
				Quit("SD_PlaySound: Priority without a sound");
			}
		asm	popf

			if (s->priority < DigiPriority)
				return(false);

			SD_PlayDigitized(DigiMap[sound],lp,rp);
			SoundPositioned = ispos;
			DigiNumber = sound;
			DigiPriority = s->priority;
		}

		return(true);
	}

	if (SoundMode == sdm_Off)
		return(false);
	if (!s->length)
		Quit("SD_PlaySound() - Zero length sound");
	if (s->priority < SoundPriority)
		return(false);

	switch (SoundMode)
	{
	case sdm_PC:
		SDL_PCPlaySound((void far *)s);
		break;
	case sdm_AdLib:
		SDL_ALPlaySound((void far *)s);
		break;
	}

	SoundNumber = sound;
	SoundPriority = s->priority;

	return(false);
}

///////////////////////////////////////////////////////////////////////////
//
//	SD_SoundPlaying() - returns the sound number that's playing, or 0 if
//		no sound is playing
//
///////////////////////////////////////////////////////////////////////////
u16int
SD_SoundPlaying(void)
{
	int	result = false;

	switch (SoundMode)
	{
	case sdm_PC:
		result = pcSound? true : false;
		break;
	case sdm_AdLib:
		result = alSound? true : false;
		break;
	}

	if (result)
		return(SoundNumber);
	else
		return(false);
}

///////////////////////////////////////////////////////////////////////////
//
//	SD_StopSound() - if a sound is playing, stops it
//
///////////////////////////////////////////////////////////////////////////
void
SD_StopSound(void)
{
	if (DigiPlaying)
		SD_StopDigitized();

	switch (SoundMode)
	{
	case sdm_PC:
		SDL_PCStopSound();
		break;
	case sdm_AdLib:
		SDL_ALStopSound();
		break;
	}

	SoundPositioned = false;

	SDL_SoundFinished();
}

///////////////////////////////////////////////////////////////////////////
//
//	SD_WaitSoundDone() - waits until the current sound is done playing
//
///////////////////////////////////////////////////////////////////////////
void
SD_WaitSoundDone(void)
{
	while (SD_SoundPlaying())
		;
}

///////////////////////////////////////////////////////////////////////////
//
//	SD_MusicOn() - turns on the sequencer
//
///////////////////////////////////////////////////////////////////////////
void
SD_MusicOn(void)
{
	sqActive = true;
}

///////////////////////////////////////////////////////////////////////////
//
//	SD_MusicOff() - turns off the sequencer and any playing notes
//
///////////////////////////////////////////////////////////////////////////
void
SD_MusicOff(void)
{
	u16int	i;


	switch (MusicMode)
	{
	case smm_AdLib:
		alFXReg = 0;
		alOut(alEffects,0);
		for (i = 0;i < sqMaxTracks;i++)
			alOut(alFreqH + i + 1,0);
		break;
	}
	sqActive = false;
}

///////////////////////////////////////////////////////////////////////////
//
//	SD_StartMusic() - starts playing the music pointed to
//
///////////////////////////////////////////////////////////////////////////
void
SD_StartMusic(MusicGroup far *music)
{
	SD_MusicOff();
asm	pushf
asm	cli

	if (MusicMode == smm_AdLib)
	{
		sqHackPtr = sqHack = music->values;
		sqHackSeqLen = sqHackLen = music->length;
		sqHackTime = 0;
		alTimeCount = 0;
		SD_MusicOn();
	}

asm	popf
}

///////////////////////////////////////////////////////////////////////////
//
//	SD_FadeOutMusic() - starts fading out the music. Call SD_MusicPlaying()
//		to see if the fadeout is complete
//
///////////////////////////////////////////////////////////////////////////
void
SD_FadeOutMusic(void)
{
	switch (MusicMode)
	{
	case smm_AdLib:
		// DEBUG - quick hack to turn the music off
		SD_MusicOff();
		break;
	}
}

///////////////////////////////////////////////////////////////////////////
//
//	SD_MusicPlaying() - returns true if music is currently playing, false if
//		not
//
///////////////////////////////////////////////////////////////////////////
int
SD_MusicPlaying(void)
{
	int	result;

	switch (MusicMode)
	{
	case smm_AdLib:
		result = false;
		// DEBUG - not written
		break;
	default:
		result = false;
	}

	return(result);
}