snes9xgx/source/ngc/audio.cpp

/****************************************************************************
 * Snes9x 1.50 
 *
 * Nintendo Gamecube Audio
 *
 * Audio is fixed to 32Khz/16bit/Stereo
 *
 * softdev July 2006
 ****************************************************************************/
#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 "ftfont.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 ();
}