/* Catacomb 3-D Source Code
 * Copyright (C) 1993-2014 Flat Rock Software
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

//
//	ID Engine
//	ID_SD.c - Sound Manager
//	v1.1d1
//	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)
//		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

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

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

//	Global variables
	boolean		SoundSourcePresent,SoundBlasterPresent,AdLibPresent,
				NeedsDigitized,NeedsMusic;
	SDMode		SoundMode;
	SMMode		MusicMode;
	dword	TimeCount;
	word		HackCount;
	word		*SoundTable;	// Really * _seg *SoundTable, but that don't work
	boolean		ssIsTandy;
	word		ssPort = 2;

//	Internal variables
static	boolean			SD_Started;
		boolean			TimerDone;
		word			TimerVal,TimerDelay10,TimerDelay25,TimerDelay100;
		dword		TimerDivisor,TimerCount;
static	char			*ParmStrings[] =
						{
							"noal",
							nil
						};
static	void			(*SoundUserHook)(void);
		word			SoundNumber,SoundPriority;
		void interrupt	(*t0OldService)(void);
//		word			t0CountTable[] = {8,8,8,8,40,40};
		long			LocalTime;

//	PC Sound variables
		volatile byte			pcLastSample,far *pcSound;
		dword		pcLengthLeft;
		word			pcSoundLookup[255];

//	AdLib variables
		boolean			alNoCheck;
		byte			far *alSound;
		word			alBlock;
		dword		alLengthLeft;
		dword		alTimeCount;
		Instrument		alZeroInst;

// This table maps channel numbers to carrier and modulator op cells
static	byte			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
		boolean			sqActive;
static	word			alFXReg;
static	ActiveTrack		*tracks[sqMaxTracks],
						mytracks[sqMaxTracks];
static	word			sqMode,sqFadeStep;
		word			far *sqHack,far *sqHackPtr,sqHackLen,sqHackSeqLen;
		long			sqHackTime;

//	Internal routines

///////////////////////////////////////////////////////////////////////////
//
//	SDL_SetTimer0() - Sets system timer 0 to the specified speed
//
///////////////////////////////////////////////////////////////////////////
#pragma	argsused
static void
SDL_SetTimer0(word speed)
{
#ifndef TPROF	// If using Borland's profiling, don't screw with the timer
	outportb(0x43,0x36);				// Change timer 0
	outportb(0x40,speed);
	outportb(0x40,speed >> 8);
	TimerDivisor = speed;
#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(word ints)
{
	SDL_SetTimer0(1192030 / ints);
}

///////////////////////////////////////////////////////////////////////////
//
//	SDL_TimingService() - Used by SDL_InitDelay() to determine a timing
//		value for the current system that we're running on
//
///////////////////////////////////////////////////////////////////////////
static void interrupt
SDL_TimingService(void)
{
	TimerVal = _CX;
	TimerDone++;

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

///////////////////////////////////////////////////////////////////////////
//
//	SDL_InitDelay() - Sets up TimerDelay's for SDL_Delay()
//
///////////////////////////////////////////////////////////////////////////
static void
SDL_InitDelay(void)
{
	int		i;
	word	timer;

	setvect(8,SDL_TimingService);		// Set to my timer 0 ISR

	SDL_SetIntsPerSec(1000);			// Time 1ms

	for (i = 0,timer = 0;i < 10;i++)	// Do timing test 10 times
	{
	asm	xor		dx,dx					// Zero DX
	asm	mov		cx,0xffff				// Put starting value in CX
	asm	mov		[TimerDone],cx			// TimerDone = false - 1
startloop:
	asm	or		[TimerDone],0
	asm	jnz		startloop				// Make sure we're at the start
loop:
	asm	test	[TimerDone],1			// See if TimerDone flag got hit
	asm	jnz		done					// Yep - drop out of the loop
	asm	loop	loop
done:

		if (0xffff - TimerVal > timer)
			timer = 0xffff - TimerVal;
	}
	timer += timer / 2;					// Use some slop
	TimerDelay10 =  timer / (1000 / 10);
	TimerDelay25 =  timer / (1000 / 25);
	TimerDelay100 = timer / (1000 / 100);

	SDL_SetTimer0(0);					// Reset timer 0

	setvect(8,t0OldService);			// Set back to old ISR
}

///////////////////////////////////////////////////////////////////////////
//
//	SDL_Delay() - Delays the specified amount of time
//
///////////////////////////////////////////////////////////////////////////
static void
SDL_Delay(word delay)
{
	if (!delay)
		return;

asm	mov		cx,[delay]
loop:
asm	test	[TimerDone],0	// Useless code - just for timing equivilency
asm	jnz		done
asm	loop	loop
done:;
}

//
//	PC Sound code
//

///////////////////////////////////////////////////////////////////////////
//
//	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

	(long)pcSound = 0;

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

asm	popf
}

///////////////////////////////////////////////////////////////////////////
//
//	SDL_PCService() - Handles playing the next sample in a PC sound
//
///////////////////////////////////////////////////////////////////////////
static void
SDL_PCService(void)
{
	byte	s;
	word	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();
		}
	}
}

///////////////////////////////////////////////////////////////////////////
//
//	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
}

// 	AdLib Code

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

asm	mov		dx,0x388
asm	mov		al,[n]
asm	out		dx,al
#if 0
	SDL_Delay(TimerDelay10);
#else
asm	in	al, dx
asm	in	al, dx
asm	in	al, dx
asm	in	al, dx
asm	in	al, dx
asm	in	al, dx
#endif

asm	mov		dx,0x389
asm	mov		al,[b]
asm	out		dx,al

asm	popf

#if 0
	SDL_Delay(TimerDelay25);
#else
asm	mov	dx,0x388
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
#endif
}

#if 0
///////////////////////////////////////////////////////////////////////////
//
//	SDL_SetInstrument() - Puts an instrument into a generator
//
///////////////////////////////////////////////////////////////////////////
static void
SDL_SetInstrument(int track,int which,Instrument far *inst,boolean percussive)
{
	byte		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

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

asm	popf
}

static void
SDL_AlSetFXInst(Instrument far *inst)
{
	byte		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);
	// DEBUG!!! - I just put this in
//	alOut(alFeedCon,inst->nConn);
}

///////////////////////////////////////////////////////////////////////////
//
//	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;

	SDL_ALStopSound();

asm	pushf
asm	cli

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

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

	SDL_AlSetFXInst(inst);

asm	popf
}

///////////////////////////////////////////////////////////////////////////
//
// 	SDL_ALSoundService() - Plays the next sample out through the AdLib card
//
///////////////////////////////////////////////////////////////////////////
static void
SDL_ALSoundService(void)
{
	byte	s;

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

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

#if 0
///////////////////////////////////////////////////////////////////////////
//
//	SDL_SelectMeasure() - sets up sequencing variables for a given track
//
///////////////////////////////////////////////////////////////////////////
static void
SDL_SelectMeasure(ActiveTrack *track)
{
	track->seq = track->moods[track->mood];
	track->nextevent = 0;
}
#endif

static void
SDL_ALService(void)
{
	byte	a,v;
	word	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 = (word far *)sqHack;
		sqHackLen = sqHackSeqLen;
		alTimeCount = sqHackTime = 0;
	}
}

///////////////////////////////////////////////////////////////////////////
//
//	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)
{
	int	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 boolean
SDL_DetectAdLib(void)
{
	byte	status1,status2;
	int		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
	SDL_Delay(TimerDelay100);

	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);
}

///////////////////////////////////////////////////////////////////////////
//
//	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	word	count = 1;

#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,4	// red
asm	out	dx,al
#endif

	HackCount++;

	if (MusicMode == smm_AdLib)
	{
		SDL_ALService();
		if (!(++count & 7))
		{
			LocalTime++;
			TimeCount++;
			if (SoundUserHook)
				SoundUserHook();
		}
		if (!(count & 3))
		{
			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 word, time to call old int handler
asm	jmp	olddone
myack:;
	outportb(0x20,0x20);	// Ack the interrupt
olddone:;

#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
}

////////////////////////////////////////////////////////////////////////////
//
//	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;
}

static void
SDL_SetTimerSpeed(void)
{
	word	rate;

	if (MusicMode == smm_AdLib)
		rate = TickBase * 8;
	else
		rate = TickBase * 2;
	SDL_SetIntsPerSec(rate);
}

//	Public routines

///////////////////////////////////////////////////////////////////////////
//
//	SD_SetSoundMode() - Sets which sound hardware to use for sound effects
//
///////////////////////////////////////////////////////////////////////////
boolean
SD_SetSoundMode(SDMode mode)
{
	boolean	result;
	word	tableoffset;

	SD_StopSound();

#ifndef	_MUSE_
	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;
	default:
		result = false;
		break;
	}
#endif

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

	SDL_SetTimerSpeed();

	return(result);
}

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

	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;
	default:
		result = false;
		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)
{
	int	i;

	if (SD_Started)
		return;

	ssIsTandy = false;
	alNoCheck = false;
#ifndef	_MUSE_
	for (i = 1;i < _argc;i++)
	{
		switch (US_CheckParm(_argv[i],ParmStrings))
		{
		case 0:						// No AdLib detection
			alNoCheck = true;
			break;
		}
	}
#endif

	SoundUserHook = 0;

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

	SDL_InitDelay();			// SDL_InitDelay() uses t0OldService

	setvect(8,SDL_t0Service);	// Set to my timer 0 ISR
	LocalTime = TimeCount = alTimeCount = 0;

	SD_SetSoundMode(sdm_Off);
	SD_SetMusicMode(smm_Off);

	if (!alNoCheck)
		AdLibPresent = SDL_DetectAdLib();

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

	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(boolean gotit,SDMode sd,SMMode sm)
{
	boolean	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();
	SDL_ShutDevice();
	SDL_CleanDevice();

	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_PlaySound() - plays the specified sound on the appropriate hardware
//
///////////////////////////////////////////////////////////////////////////
void
SD_PlaySound(soundnames sound)
{
	SoundCommon	far *s;

	if ((SoundMode == sdm_Off) || (sound == -1))
		return;

	s = MK_FP(SoundTable[sound],0);
	if (!s)
		Quit("SD_PlaySound() - Uncached sound");
	if (!s->length)
		Quit("SD_PlaySound() - Zero length sound");
	if (s->priority < SoundPriority)
		return;

	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;
}

///////////////////////////////////////////////////////////////////////////
//
//	SD_SoundPlaying() - returns the sound number that's playing, or 0 if
//		no sound is playing
//
///////////////////////////////////////////////////////////////////////////
word
SD_SoundPlaying(void)
{
	boolean	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)
{
	switch (SoundMode)
	{
	case sdm_PC:
		SDL_PCStopSound();
		break;
	case sdm_AdLib:
		SDL_ALStopSound();
		break;
	}

	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)
{
	word	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
//
///////////////////////////////////////////////////////////////////////////
boolean
SD_MusicPlaying(void)
{
	boolean	result;

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

	return(result);
}