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view src/video/ataricommon/SDL_ikbdinterrupt.S @ 4216:5b99971a27b4 SDL-1.2

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Fixed bug #698 Hans de Goede 2009-02-13 01:10:52 PST Since the new "glitch free" version of pulseaudio (used in Fedora 10 amongst others), the sound of SDL using apps (like a simple playmus call) has been crackling. While looking in to fixing this I noticed that the current pulseaudio code in SDL uses pa_simple. However pa_simple uses a thread to pump pulseaudio events and ipc, given that SDL already has its own thread for audio handling this is clearly suboptimal, leading to unnecessary context switching IPC, etc. Also pa_simple does not allow one to implement the WaitAudio() callback for SDL audiodrivers properly. Given that my work is mostly a rewrite (although some original pieces remain) I'm attaching the new .c and .h file, as that is easier to review then the huge diff. Let me know if you also want the diff. This new version has the following features: -no longer use an additional thread next to the SDL sound thread -do not crackle with glitch free audio -when used with a newer pulse, which does glitch free audio, the total latency is the same as with the alsa driver -proper WaitAudio() implementation, saving another mixlen worth of latency -adds a WaitDone() implementation This patch has been written in consultancy with Lennart Poetering (the pulseaudio author) and has been reviewed by him for correct use of the pa API.
author Sam Lantinga <slouken@libsdl.org>
date Mon, 21 Sep 2009 09:27:08 +0000
parents a1b03ba2fcd0
children 40e4536ad0c3
line wrap: on
line source

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2009 Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 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
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga
    slouken@libsdl.org
*/

/*
 *	IKBD 6301 interrupt routine
 *
 *	Patrice Mandin
 */

	.text

	.globl	_SDL_AtariIkbdInstall
	.globl	_SDL_AtariIkbdUninstall

	.globl	_SDL_AtariIkbd_keyboard
	.globl	_SDL_AtariIkbd_mouseb
	.globl	_SDL_AtariIkbd_mousex
	.globl	_SDL_AtariIkbd_mousey
	.globl	_SDL_AtariIkbd_joystick

	.globl	_SDL_AtariIkbd_enabled

/*--- Install our IKBD vector ---*/

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

	| Disable interrupts

	movew	#0x2700,sr

	| Save MFP registers used for keyboard

	lea	0xfffffa00:w,a0
	btst	#6,a0@(0x09)
	sne		ikbd_ierb
	btst	#6,a0@(0x15)
	sne		ikbd_imrb

	| Set our routine

	movel	0x118:w,old_ikbd
	movel	#ikbd,0x118:w
	bset	#6,0xfffffa09:w	| IERB
	bset	#6,0xfffffa15:w	| IMRB

	| Set mouse relative mode

	moveb	#8,0xfffffc02:w

	| Reenable interrupts

	movew	#0x2300,sr

	| Interrupts done

	movew	#0xffff,_SDL_AtariIkbd_enabled

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

/*--- Uninstall our IKBD vector ---*/

_SDL_AtariIkbdUninstall:
	movel	a0,sp@-

	| Disable interrupts

	movew	#0x2700,sr

	| Restore previous MFP registers

	lea	0xfffffa00:w,a0

	bclr	#6,a0@(0x09)
	tstb	ikbd_ierb
	beqs	ikbd_restoreierb
	bset	#6,a0@(0x09)
ikbd_restoreierb:

	bclr	#6,a0@(0x15)
	tstb	ikbd_imrb
	beqs	ikbd_restoreimrb
	bset	#6,a0@(0x15)
ikbd_restoreimrb:

	movel	old_ikbd,0x118:w

	| Clear keyboard buffer

	lea	0xfffffc00:w,a0
ikbd_videbuffer:
	btst	#0,a0@
	beqs	ikbd_finbuffer
	tstb	a0@(0x02)
	bras	ikbd_videbuffer
ikbd_finbuffer:

	| Reenable interrupts

	movew	#0x2300,sr

	movel	sp@+,a0
	rts

	.bss

	.even
	.comm	ikbd_ierb,1
	.comm	ikbd_imrb,1

/*--- Our custom IKBD vector ---*/

	.text
	.even
	.ascii	"XBRA"
	.ascii	"LSDL"
	.comm	old_ikbd,4*1
ikbd:
	| Check if source is IKBD or MIDI
	btst	#0,0xfffffc00.w
	beqs	ikbd_oldmidi

	moveml	d0-d1/a0,sp@-
	moveb	0xfffffc02:w,d0

	| Joystick packet ?
	
	cmpb	#0xff,d0
	beqs	ikbd_yes_joystick

	| Mouse packet ?

	cmpb	#0xf8,d0
	bmis	ikbd_no_mouse
	cmpb	#0xfc,d0
	bpls	ikbd_no_mouse

	| Mouse packet, byte #1

ikbd_yes_mouse:
	andw	#3,d0
	movew	d0,_SDL_AtariIkbd_mouseb

	movel	#ikbd_mousex,0x118:w
	bras	ikbd_endit_stack

	| Joystick packet, byte #1

ikbd_yes_joystick:
	movel	#ikbd_joystick,0x118:w
	bras	ikbd_endit_stack

	| Keyboard press/release

ikbd_no_mouse:
	moveb	d0,d1
	lea		_SDL_AtariIkbd_keyboard,a0
	andw	#0x7f,d1
	tas		d0
	spl		a0@(0,d1:w)

	| End of interrupt

ikbd_endit_stack:
	moveml	sp@+,d0-d1/a0
ikbd_endit:
	bclr	#6,0xfffffa11:w
	rte

	| Call old MIDI interrupt

ikbd_oldmidi:
	movel	old_ikbd,sp@-
	rts

	| Mouse packet, byte #2

ikbd_mousex:

	| Check if source is IKBD or MIDI
	btst	#0,0xfffffc00.w
	beqs	ikbd_oldmidi

	movew	d0,sp@-

	moveb	0xfffffc02:w,d0
	extw	d0
	addw	d0,_SDL_AtariIkbd_mousex

	movew	sp@+,d0

	movel	#ikbd_mousey,0x118:w
	bras	ikbd_endit

	| Mouse packet, byte #3

ikbd_mousey:

	| Check if source is IKBD or MIDI
	btst	#0,0xfffffc00.w
	beqs	ikbd_oldmidi

	movew	d0,sp@-

	moveb	0xfffffc02:w,d0
	extw	d0
	addw	d0,_SDL_AtariIkbd_mousey

	movew	sp@+,d0

	movel	#ikbd,0x118:w
	bras	ikbd_endit

	| Joystick packet, byte #2

ikbd_joystick:

	| Check if source is IKBD or MIDI
	btst	#0,0xfffffc00.w
	beqs	ikbd_oldmidi

	moveb	0xfffffc02:w,_SDL_AtariIkbd_joystick+1

	movel	#ikbd,0x118:w
	bras	ikbd_endit

	.data
	
	.even
_SDL_AtariIkbd_enabled:
	.word	0

	.bss

	.even
	.comm	_SDL_AtariIkbd_keyboard,128
	.comm	_SDL_AtariIkbd_mousex,2
	.comm	_SDL_AtariIkbd_mousey,2
	.comm	_SDL_AtariIkbd_mouseb,2
	.comm	_SDL_AtariIkbd_joystick,2