snes9xgx/source/ngc/audio.cpp

/****************************************************************************
 * Snes9x 1.51 Nintendo Wii/Gamecube Port
 *
 * softdev July 2006
 *
 * audio.cpp
 *
 * Audio driver
 * Audio is fixed to 32Khz/16bit/Stereo
 ***************************************************************************/

#include <gccore.h>
#include <ogcsys.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "snes9x.h"
#include "memmap.h"
#include "debug.h"
#include "cpuexec.h"
#include "ppu.h"
#include "apu.h"
#include "display.h"
#include "gfx.h"
#include "soundux.h"
#include "spc700.h"
#include "spc7110.h"
#include "controls.h"

#include "video.h"
#include "menudraw.h"

/*** Double buffered audio ***/
#define AUDIOBUFFER 2048
static unsigned char soundbuffer[2][AUDIOBUFFER]
  __attribute__ ((__aligned__ (32)));
static int whichab = 0;	/*** Audio buffer flip switch ***/
extern int ConfigRequested;

#define AUDIOSTACK 16384
lwpq_t audioqueue;
lwp_t athread;
static uint8 astack[AUDIOSTACK];

/****************************************************************************
 * Audio Threading
 ***************************************************************************/
static void *
AudioThread (void *arg)
{
	LWP_InitQueue (&audioqueue);

	while (1)
	{
		whichab ^= 1;
		if (ConfigRequested)
			memset (soundbuffer[whichab], 0, AUDIOBUFFER);
		else
		{
			so.samples_mixed_so_far = so.play_position = 0;
			S9xMixSamples (soundbuffer[whichab], AUDIOBUFFER >> 1);
		}
		LWP_ThreadSleep (audioqueue);
	}

	return NULL;
}

/****************************************************************************
 * MixSamples
 * This continually calls S9xMixSamples On each DMA Completion
 ***************************************************************************/
static void
GCMixSamples ()
{
	AUDIO_StopDMA ();

	DCFlushRange (soundbuffer[whichab], AUDIOBUFFER);
	AUDIO_InitDMA ((u32) soundbuffer[whichab], AUDIOBUFFER);
	AUDIO_StartDMA ();

	LWP_ThreadSignal (audioqueue);
}

/****************************************************************************
 * InitGCAudio
 ***************************************************************************/
void
InitGCAudio ()
{
	AUDIO_SetDSPSampleRate (AI_SAMPLERATE_32KHZ);
	AUDIO_RegisterDMACallback (GCMixSamples);

	LWP_CreateThread (&athread, AudioThread, NULL, astack, AUDIOSTACK, 80);
}

/****************************************************************************
 * AudioStart
 *
 * Called to kick off the Audio Queue
 ***************************************************************************/
void
AudioStart ()
{
	GCMixSamples ();
}