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116 lines
2.8 KiB
C
116 lines
2.8 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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*
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* audio.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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#define SAMPLERATE 48000
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unsigned char audiobuffer[2][64 * 1024] ATTRIBUTE_ALIGN(32);
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/*** Allow for up to 1 full second ***/
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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 int isWriting = 0; /*** Bool for buffer writes ***/
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static int buffSize[2]; /*** Hold size of current buffer ***/
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static int whichab = 0; /*** Which Audio Buffer is in use ***/
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static int isPlaying; /*** Is Playing ***/
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static void AudioSwitchBuffers()
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{
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if ( buffSize[whichab] ) {
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AUDIO_StopDMA();
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AUDIO_InitDMA((u32)audiobuffer[whichab], buffSize[whichab]);
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DCFlushRange(audiobuffer[whichab], buffSize[whichab]);
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AUDIO_StartDMA();
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isPlaying = 0;
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}
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whichab ^= 1;
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buffSize[whichab] = 0;
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}
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void InitialiseSound()
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{
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AUDIO_Init(NULL); /*** Start audio subsystem ***/
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AUDIO_SetDSPSampleRate(AI_SAMPLERATE_48KHZ);
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AUDIO_RegisterDMACallback( AudioSwitchBuffers );
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buffSize[0] = buffSize[1] = 0;
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}
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void StartAudio()
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{
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AUDIO_StartDMA();
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}
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void StopAudio()
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{
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AUDIO_StopDMA();
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buffSize[0] = buffSize[1] = 0;
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}
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static inline unsigned short FLIP16(unsigned short b)
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{
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return((b<<8)|((b>>8)&0xFF));
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}
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static inline u32 FLIP32(u32 b)
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{
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return( (b<<24) | ((b>>8)&0xFF00) | ((b<<8)&0xFF0000) | ((b>>24)&0xFF) );
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}
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/****************************************************************************
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* Audio incoming is monaural
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*
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* PlaySound will simply mix to get it right
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****************************************************************************/
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#define AUDIOBUFFER ((50 * SAMPLERATE) / 1000 ) << 4
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static int isPlaying = 0;
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static short MBuffer[ 8 * 96000 / 50 ];
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void PlaySound( unsigned int *Buffer, int count )
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{
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int P;
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unsigned short *s = (unsigned short *)&MBuffer[0];
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unsigned int *d = (unsigned int *)&audiobuffer[whichab][buffSize[whichab]];
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unsigned int c;
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int ms;
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isWriting = 1;
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for ( P = 0; P < count; P++ ) {
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MBuffer[P] = Buffer[P];
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}
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/*** Now do Mono - Stereo Conversion ***/
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ms = count;
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do
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{
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c = 0xffff & *s++;
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*d++ = (c | (c<<16));
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} while(--ms);
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buffSize[whichab] += ( count << 2 );
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/*** This is the kicker for the entire audio loop ***/
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if ( isPlaying == 0 )
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{
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if ( buffSize[whichab] > AUDIOBUFFER )
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{
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isPlaying = 1;
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AudioSwitchBuffers();
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}
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}
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isWriting = 0;
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}
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