view src/audio/mint/SDL_mintaudio_mcsn.h @ 968:4675910b0b7b

Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST) From: Hannu Savolainen Subject: Re: SDL uses obsolete OSS features I did some work on getting OSS to work better with SDL. There have been some problems with select which should be fixed now. I'm having some problems in understanding what is the purpose of the DSP_WaitAudio() routine. I added a return to the very beginning of this routine and commendted out the define for USE_BLOCKING_WRITES. At least lbreakout2 seems to work as well as earlier. The latencies are the same. An ordinary blocking write does exactly the same thing than DSP_WaitAudio does. So I would recommend using the USE_BLOCKING_WRITES approach and removing everything from the DSP_WaitAudio routine. Also enabling USE_BLOCKING_WRITES makes it possible to simplify DSP_PlayAudio() because you don't need to handle the partial writes (the do-while loop). Attached is a patch against SDL-1.2.7. After these changes SDL will use OSS as it's designed to be used (make it as simple as possible). This code should work with all OSS implementations because it uses only the very fundamental features that have been there since the jurassic times.
author Sam Lantinga <slouken@libsdl.org>
date Fri, 12 Nov 2004 21:39:04 +0000
parents b8d311d90021
children d910939febfa
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/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2004 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
*/

/*
	MCSN control structure

	Patrice Mandin
*/

#ifndef _SDL_mintaudio_mcsh_h
#define _SDL_mintaudio_mcsh_h

typedef struct {
	unsigned short version;	/* Version */
	unsigned short size;	/* Size of structure */

	unsigned short play;	/* Replay capability */
	unsigned short record;	/* Record capability */
	unsigned short dsp;		/* DSP56K present */
	unsigned short pint;	/* Interrupt at end of replay */
	unsigned short rint;	/* Interrupt at end of record */

	unsigned long res1;		/* Frequency of external clock */
	unsigned long res2;
	unsigned long res3;
	unsigned long res4;
} cookie_mcsn_t __attribute__((packed));

enum {
	MCSN_ST=0,
	MCSN_TT,
	MCSN_STE=MCSN_TT,
	MCSN_FALCON,
	MCSN_MAC=MCSN_FALCON
};

#define SETSMPFREQ	7	/* Set sample frequency */

#endif /* _SDL_mintaudio_mcsh_h */