/*

    SDL - Simple DirectMedia Layer

    Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002  Sam Lantinga

    This library is free software; you can redistribute it and/or

    modify it under the terms of the GNU Library General Public

    License as published by the Free Software Foundation; either

    version 2 of the License, or (at your option) any later version.

    This library 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

    Library General Public License for more details.

    You should have received a copy of the GNU Library General Public

    License along with this library; if not, write to the Free

    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

    Sam Lantinga

    slouken@libsdl.org

*/

/*

	Audio interrupts

	Patrice Mandin, Didier Méquignon

 */

	.text

	.globl	_SDL_MintAudio_Callback

	.globl	_SDL_MintAudio_XbiosInterrupt

	.globl	_SDL_MintAudio_XbiosInterruptMeasureClock

	.globl	_SDL_MintAudio_Dma8Interrupt

	.globl	_SDL_MintAudio_StfaInterrupt

	.globl	_SDL_MintAudio_mutex

	.globl	_SDL_MintAudio_audiobuf

	.globl	_SDL_MintAudio_numbuf

	.globl	_SDL_MintAudio_audiosize

	.globl	_SDL_MintAudio_clocktics

	.globl	_SDL_MintAudio_hasfpu

	.globl	_SDL_MintAudio_stfa

/*

	How it works:

	- Audio is playing buffer #0 (resp. #1)

	- We must calculate a sample in buffer #1 (resp. #0)

	  so we first call the callback to do it

	- Then we swap the buffers

*/

#define	savptr	0x4a2

#define	savamt	0x46

/*--- Xbios interrupt vector to measure Falcon external clock ---*/

_SDL_MintAudio_XbiosInterruptMeasureClock:          /* 1 mS */

	btst	#0,0xFFFF8901:w	/* state DMA sound */

	beqs	SDL_MintAudio_EndIntMeasure

	addql	#1,_SDL_MintAudio_clocktics

SDL_MintAudio_EndIntMeasure:

	bclr	#5,0xFFFFFA0F:w	/* Clear service bit */

	rte

/*--- Xbios interrupt vector ---*/

_SDL_MintAudio_XbiosInterrupt:

	/* Reenable interrupts, so other interrupts can work */

	movew	#0x2300,sr

	/* Clear service bit, so other MFP interrupts can work */

	bclr	#5,0xfffffa0f:w

	/* Check if we are not already running */

	tstw	_SDL_MintAudio_mutex

	bne	SDL_MintAudio_XbiosEnd

	notw	_SDL_MintAudio_mutex

	/* Swap buffers */

	eorw	#1,_SDL_MintAudio_numbuf

	moveml	d0-d7/a0-a6,sp@-

	/* Save FPU if needed */

	tstw	_SDL_MintAudio_hasfpu

	beqs	SDL_MintAudio_Xbios_nofpu1

	.chip	68060

	fsave	sp@-

	fmoveml fpcr/fpsr/fpiar,sp@-

	fmovemx	fp0-fp7,sp@-

	.chip	68000

SDL_MintAudio_Xbios_nofpu1:

	/* Callback */

	jsr	_SDL_MintAudio_Callback

	/* Restore FPU if needed */

	tstw	_SDL_MintAudio_hasfpu

	beqs	SDL_MintAudio_Xbios_nofpu2

	.chip	68060

	fmovemx	sp@+,fp0-fp7

	fmoveml	sp@+,fpcr/fpsr/fpiar

	frestore	sp@+

	.chip	68000

SDL_MintAudio_Xbios_nofpu2:

	/* Reserve space for registers */

	subl	#savamt,savptr

	/* Set new buffer */

	moveq	#0,d0

	movel	_SDL_MintAudio_audiosize,d1

	movew	_SDL_MintAudio_numbuf,d0

	lsll	#2,d0

	lea	_SDL_MintAudio_audiobuf,a0

	movel	a0@(d0:l),a1

	lea	a1@(d1:l),a2

	movel	a2,sp@-

	movel	a1,sp@-

	clrw	sp@-

	movew	#131,sp@-

	trap	#14

	lea	sp@(12),sp

	/* Restore registers space */

	addl	#savamt,savptr

	moveml	sp@+,d0-d7/a0-a6

	clrw	_SDL_MintAudio_mutex

SDL_MintAudio_XbiosEnd:

	rte

/*--- DMA 8 bits interrupt vector ---*/

_SDL_MintAudio_Dma8Interrupt:

	/* Reenable interrupts, so other interrupts can work */

	movew	#0x2300,sr

	/* Clear service bit, so other MFP interrupts can work */

	bclr	#5,0xfffffa0f:w

	/* Check if we are not already running */

	tstw	_SDL_MintAudio_mutex

	bne	SDL_MintAudio_Dma8End

	notw	_SDL_MintAudio_mutex

	/* Swap buffers */

	eorw	#1,_SDL_MintAudio_numbuf

	moveml	d0-d1/a0-a1,sp@-

	/* Save FPU if needed */

	tstw	_SDL_MintAudio_hasfpu

	beqs	SDL_MintAudio_Dma8_nofpu1

	.chip	68060

	fsave	sp@-

	fmoveml fpcr/fpsr/fpiar,sp@-

	fmovemx	fp0-fp7,sp@-

	.chip	68000

SDL_MintAudio_Dma8_nofpu1:

	/* Callback */

	jsr	_SDL_MintAudio_Callback

	/* Restore FPU if needed */

	tstw	_SDL_MintAudio_hasfpu

	beqs	SDL_MintAudio_Dma8_nofpu2

	.chip	68060

	fmovemx	sp@+,fp0-fp7

	fmoveml	sp@+,fpcr/fpsr/fpiar

	frestore	sp@+

	.chip	68000

SDL_MintAudio_Dma8_nofpu2:

	/* Set new buffer */

	moveq	#0,d0

	movew	_SDL_MintAudio_numbuf,d0

	lslw	#2,d0

	lea	_SDL_MintAudio_audiobuf,a0

	movel	a0@(d0:w),d1

	/* Modify DMA addresses */

	lea	0xffff8900:w,a0

	moveb	d1,a0@(0x07)	/* Start address */

	rorl	#8,d1

	moveb	d1,a0@(0x05)

	rorl	#8,d1

	moveb	d1,a0@(0x03)

	swap	d1

	addl	_SDL_MintAudio_audiosize,d1

	moveb	d1,a0@(0x13)	/* End address */

	rorl	#8,d1

	moveb	d1,a0@(0x11)

	rorl	#8,d1

	moveb	d1,a0@(0x0f)

	moveml	sp@+,d0-d1/a0-a1

	clrw	_SDL_MintAudio_mutex

SDL_MintAudio_Dma8End:

	rte

/*--- STFA interrupt vector ---*/

STFA_SOUND_START	=	6

STFA_SOUND_END		=	STFA_SOUND_START+8

_SDL_MintAudio_StfaInterrupt:

	/* Reenable interrupts, so other interrupts can work */

	movew	#0x2300,sr

	/* Check if we are not already running */

	tstw	_SDL_MintAudio_mutex

	bnes	SDL_MintAudio_StfaEnd

	notw	_SDL_MintAudio_mutex

	/* Swap buffers */

	eorw	#1,_SDL_MintAudio_numbuf

	moveml	d0-d7/a0-a6,sp@-

	/* Save FPU if needed */

	tstw	_SDL_MintAudio_hasfpu

	beqs	SDL_MintAudio_Stfa_nofpu1

	.chip	68060

	fsave	sp@-

	fmoveml fpcr/fpsr/fpiar,sp@-

	fmovemx	fp0-fp7,sp@-

	.chip	68000

SDL_MintAudio_Stfa_nofpu1:

	/* Callback */

	jsr	_SDL_MintAudio_Callback

	/* Restore FPU if needed */

	tstw	_SDL_MintAudio_hasfpu

	beqs	SDL_MintAudio_Stfa_nofpu2

	.chip	68060

	fmovemx	sp@+,fp0-fp7

	fmoveml	sp@+,fpcr/fpsr/fpiar

	frestore	sp@+

	.chip	68000

SDL_MintAudio_Stfa_nofpu2:

	/* Set new buffer */

	moveq	#0,d0

	movel	_SDL_MintAudio_stfa,a1

	movew	_SDL_MintAudio_numbuf,d0

	lslw	#2,d0

	lea	_SDL_MintAudio_audiobuf,a0

	movel	a0@(d0:w),d1

	/* Modify STFA replay buffers */

	movel	d1,a1@(STFA_SOUND_START)

	addl	_SDL_MintAudio_audiosize,d1

	movel	d1,a1@(STFA_SOUND_END)

	moveml	sp@+,d0-d7/a0-a6

	clrw	_SDL_MintAudio_mutex

SDL_MintAudio_StfaEnd:

	rte