view src/audio/mint/SDL_mintaudio_dma8.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 185acc07127a
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
*/

/*
	DMA 8bits and Falcon Codec audio definitions

	Patrice Mandin, Didier Méquignon
*/

#ifndef _SDL_mintaudio_dma8_h
#define _SDL_mintaudio_dma8_h

#define DMAAUDIO_IO_BASE (0xffff8900)
struct DMAAUDIO_IO_S {
	unsigned char int_ctrl;
	unsigned char control;

	unsigned char dummy1;
	unsigned char start_high;
	unsigned char dummy2;
	unsigned char start_mid;
	unsigned char dummy3;
	unsigned char start_low;

	unsigned char dummy4;
	unsigned char cur_high;
	unsigned char dummy5;
	unsigned char cur_mid;
	unsigned char dummy6;
	unsigned char cur_low;

	unsigned char dummy7;
	unsigned char end_high;
	unsigned char dummy8;
	unsigned char end_mid;
	unsigned char dummy9;
	unsigned char end_low;

	unsigned char dummy10[12];

	unsigned char track_ctrl; /* CODEC only */
	unsigned char sound_ctrl;
	unsigned short sound_data;
	unsigned short sound_mask;

	unsigned char dummy11[10];
	
	unsigned short dev_ctrl;
	unsigned short dest_ctrl;
	unsigned short sync_div;
	unsigned char track_rec;
	unsigned char adderin_input;
	unsigned char channel_input;
	unsigned char channel_amplification;
	unsigned char channel_reduction;
	
	unsigned char dummy12[6];

	unsigned char data_direction;
	unsigned char dummy13;
	unsigned char dev_data;
};
#define DMAAUDIO_IO ((*(volatile struct DMAAUDIO_IO_S *)DMAAUDIO_IO_BASE))

#endif /* _SDL_mintaudio_dma8_h */