149 lines
3.7 KiB
C
149 lines
3.7 KiB
C
/****************************************************************************
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* FCE Ultra 0.98.12
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* Nintendo Wii/Gamecube Port
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*
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* Tantric September 2008
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* eke-eke October 2008
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*
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* gcaudio.c
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*
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* Audio driver
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****************************************************************************/
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#include <gccore.h>
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#include <string.h>
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#define SAMPLERATE 32000
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#define MIXBUFSIZE_BYTES 16000
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#define MIXBUFSIZE_SHORT (MIXBUFSIZE_BYTES / 2)
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#define MIXBUFSIZE_WORDS (MIXBUFSIZE_BYTES / 4)
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#define SOUNDBUFSIZE 2048
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static u8 ConfigRequested = 0;
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static u8 soundbuffer[2][SOUNDBUFSIZE] ATTRIBUTE_ALIGN(32);
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static u8 mixbuffer[MIXBUFSIZE_BYTES];
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static int mixhead = 0;
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static int mixtail = 0;
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static int whichab = 0;
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static int IsPlaying = 0;
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/****************************************************************************
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* MixerCollect
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*
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* Collects sound samples from mixbuffer and puts them into outbuffer
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* Makes sure to align them to 32 bytes for AUDIO_InitDMA
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***************************************************************************/
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static int MixerCollect( u8 *outbuffer, int len )
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{
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u32 *dst = (u32 *)outbuffer;
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u32 *src = (u32 *)mixbuffer;
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int done = 0;
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// Always clear output buffer
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memset(outbuffer, 0, len);
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while ( ( mixtail != mixhead ) && ( done < len ) )
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{
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*dst++ = src[mixtail++];
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if (mixtail == MIXBUFSIZE_WORDS) mixtail = 0;
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done += 4;
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}
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// Realign to 32 bytes for DMA
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mixtail -= ((done&0x1f) >> 2);
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if (mixtail < 0)
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mixtail += MIXBUFSIZE_WORDS;
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done &= ~0x1f;
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return done;
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}
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/****************************************************************************
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* AudioSwitchBuffers
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*
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* Manages which buffer is played next
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***************************************************************************/
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static void AudioSwitchBuffers()
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{
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if ( !ConfigRequested )
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{
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int len = MixerCollect( soundbuffer[whichab], SOUNDBUFSIZE );
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if (len == 0)
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return;
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DCFlushRange(soundbuffer[whichab], len);
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AUDIO_InitDMA((u32)soundbuffer[whichab], len);
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AUDIO_StartDMA();
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whichab ^= 1;
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IsPlaying = 1;
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}
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else IsPlaying = 0;
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}
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/****************************************************************************
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* InitialiseAudio
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*
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* Initializes sound system on first load of emulator
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***************************************************************************/
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void InitialiseAudio()
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{
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AUDIO_Init(NULL); // Start audio subsystem
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AUDIO_SetDSPSampleRate(AI_SAMPLERATE_32KHZ);
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AUDIO_RegisterDMACallback( AudioSwitchBuffers );
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memset(soundbuffer, 0, SOUNDBUFSIZE*2);
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memset(mixbuffer, 0, MIXBUFSIZE_BYTES);
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}
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/****************************************************************************
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* StopAudio
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*
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* Pause audio output when returning to menu
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***************************************************************************/
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void StopAudio()
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{
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AUDIO_StopDMA();
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IsPlaying = 0;
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}
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/****************************************************************************
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* ResetAudio
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*
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* Reset audio output when loading a new game
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***************************************************************************/
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void ResetAudio()
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{
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memset(soundbuffer, 0, SOUNDBUFSIZE*2);
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memset(mixbuffer, 0, MIXBUFSIZE_BYTES);
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mixhead = mixtail = 0;
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}
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/****************************************************************************
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* PlaySound
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*
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* Puts incoming mono samples into mixbuffer
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* Splits mono samples into two channels (stereo)
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****************************************************************************/
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void PlaySound( int16_t *Buffer, int count )
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{
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u32 *dst = (u32 *)mixbuffer;
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int i;
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for( i = 0; i < count; i++ )
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{
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u16 sample;
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sample = (Buffer[i] & 0xffff);
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dst[mixhead++] = sample | ( sample << 16);
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if (mixhead == MIXBUFSIZE_WORDS)
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mixhead = 0;
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}
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// Restart Sound Processing if stopped
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if (IsPlaying == 0)
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{
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AudioSwitchBuffers ();
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}
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}
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