view src/audio/mint/SDL_mintaudio.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 39b5606fa543
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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
*/

/*
	MiNT audio driver

	Patrice Mandin
*/

#ifndef _SDL_mintaudio_h
#define _SDL_mintaudio_h

#include "SDL_sysaudio.h"
#include "SDL_mintaudio_stfa.h"

/* Hidden "this" pointer for the audio functions */
#define _THIS	SDL_AudioDevice *this

/* 16 predivisors with 3 clocks max. */
#define MINTAUDIO_maxfreqs		(16*3)		

typedef struct {
	Uint32	frequency;
	Uint32	masterclock;
	Uint32	predivisor;
} mint_frequency_t;

struct SDL_PrivateAudioData {
	mint_frequency_t	frequencies[MINTAUDIO_maxfreqs];
	int 	freq_count;		/* Number of frequencies in the array */
	int		numfreq;		/* Number of selected frequency */
};

/* Old variable names */

#define MINTAUDIO_frequencies	(this->hidden->frequencies)
#define MINTAUDIO_freqcount		(this->hidden->freq_count)
#define MINTAUDIO_numfreq		(this->hidden->numfreq)

/* _MCH cookie (values>>16) */
enum {
	MCH_ST=0,
	MCH_STE,
	MCH_TT,
	MCH_F30
};

/* Master clocks for replay frequencies */
#define MASTERCLOCK_STE		8010666		/* Not sure of this one */
#define MASTERCLOCK_TT		16107953	/* Not sure of this one */
#define MASTERCLOCK_FALCON1	25175000
#define MASTERCLOCK_FALCON2	32000000	/* Only usable for DSP56K */
#define MASTERCLOCK_FALCONEXT	-1		/* Clock on DSP56K port, unknown */
#define MASTERCLOCK_44K		22579200	/* Standard clock for 44.1 Khz */
#define MASTERCLOCK_48K		24576000	/* Standard clock for 48 Khz */

/* Master clock predivisors */
#define MASTERPREDIV_STE	160
#define MASTERPREDIV_TT		320
#define MASTERPREDIV_FALCON	256
#define MASTERPREDIV_MILAN	256

/* MFP 68901 interrupt sources */
enum {
	MFP_PARALLEL=0,
	MFP_DCD,
	MFP_CTS,
	MFP_BITBLT,
	MFP_TIMERD,
	MFP_BAUDRATE=MFP_TIMERD,
	MFP_TIMERC,
	MFP_200HZ=MFP_TIMERC,
	MFP_ACIA,
	MFP_DISK,
	MFP_TIMERB,
	MFP_HBLANK=MFP_TIMERB,
	MFP_TERR,
	MFP_TBE,
	MFP_RERR,
	MFP_RBF,
	MFP_TIMERA,
	MFP_DMASOUND=MFP_TIMERA,
	MFP_RING,
	MFP_MONODETECT
};

/* Xbtimer() timers */
enum {
	XB_TIMERA=0,
	XB_TIMERB,
	XB_TIMERC,
	XB_TIMERD
};

/* Variables */
extern SDL_AudioDevice *SDL_MintAudio_device;
extern Uint8 *SDL_MintAudio_audiobuf[2];	/* Pointers to buffers */
extern unsigned long SDL_MintAudio_audiosize;		/* Length of audio buffer=spec->size */
extern unsigned short SDL_MintAudio_numbuf;		/* Buffer to play */
extern unsigned short SDL_MintAudio_mutex;
extern cookie_stfa_t *SDL_MintAudio_stfa;
extern unsigned long SDL_MintAudio_clocktics;

/* Functions */
void SDL_MintAudio_Callback(void);
void SDL_MintAudio_AddFrequency(_THIS, Uint32 frequency, Uint32 clock, Uint32 prediv);
int SDL_MintAudio_SearchFrequency(_THIS, int desired_freq);

/* ASM interrupt functions */
void SDL_MintAudio_GsxbInterrupt(void);
void SDL_MintAudio_EmptyGsxbInterrupt(void);
void SDL_MintAudio_XbiosInterruptMeasureClock(void);
void SDL_MintAudio_XbiosInterrupt(void);
void SDL_MintAudio_Dma8Interrupt(void);
void SDL_MintAudio_StfaInterrupt(void);

#endif /* _SDL_mintaudio_h */