SDL_dcaudio.c
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/*
SDL - Simple DirectMedia Layer
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Copyright (C) 1997-2006 Sam Lantinga
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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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
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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Sam Lantinga
slouken@libsdl.org
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#include "SDL_config.h"
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/* Output dreamcast aica */
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#include "SDL_timer.h"
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#include "SDL_audio.h"
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#include "../SDL_audiomem.h"
#include "../SDL_audio_c.h"
#include "../SDL_audiodev_c.h"
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#include "SDL_dcaudio.h"
#include "aica.h"
#include <dc/spu.h>
/* Audio driver functions */
static int DCAUD_OpenAudio(_THIS, SDL_AudioSpec *spec);
static void DCAUD_WaitAudio(_THIS);
static void DCAUD_PlayAudio(_THIS);
static Uint8 *DCAUD_GetAudioBuf(_THIS);
static void DCAUD_CloseAudio(_THIS);
/* Audio driver bootstrap functions */
static int DCAUD_Available(void)
{
return 1;
}
static void DCAUD_DeleteDevice(SDL_AudioDevice *device)
{
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SDL_free(device->hidden);
SDL_free(device);
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}
static SDL_AudioDevice *DCAUD_CreateDevice(int devindex)
{
SDL_AudioDevice *this;
/* Initialize all variables that we clean on shutdown */
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this = (SDL_AudioDevice *)SDL_malloc(sizeof(SDL_AudioDevice));
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if ( this ) {
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SDL_memset(this, 0, (sizeof *this));
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this->hidden = (struct SDL_PrivateAudioData *)
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SDL_malloc((sizeof *this->hidden));
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}
if ( (this == NULL) || (this->hidden == NULL) ) {
SDL_OutOfMemory();
if ( this ) {
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SDL_free(this);
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}
return(0);
}
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SDL_memset(this->hidden, 0, (sizeof *this->hidden));
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/* Set the function pointers */
this->OpenAudio = DCAUD_OpenAudio;
this->WaitAudio = DCAUD_WaitAudio;
this->PlayAudio = DCAUD_PlayAudio;
this->GetAudioBuf = DCAUD_GetAudioBuf;
this->CloseAudio = DCAUD_CloseAudio;
this->free = DCAUD_DeleteDevice;
spu_init();
return this;
}
AudioBootStrap DCAUD_bootstrap = {
"dcaudio", "Dreamcast AICA audio",
DCAUD_Available, DCAUD_CreateDevice
};
/* This function waits until it is possible to write a full sound buffer */
static void DCAUD_WaitAudio(_THIS)
{
if (this->hidden->playing) {
/* wait */
while(aica_get_pos(0)/this->spec.samples == this->hidden->nextbuf) {
thd_pass();
}
}
}
#define SPU_RAM_BASE 0xa0800000
static void spu_memload_stereo8(int leftpos,int rightpos,void *src0,size_t size)
{
uint8 *src = src0;
uint32 *left = (uint32*)(leftpos +SPU_RAM_BASE);
uint32 *right = (uint32*)(rightpos+SPU_RAM_BASE);
size = (size+7)/8;
while(size--) {
unsigned lval,rval;
lval = *src++;
rval = *src++;
lval|= (*src++)<<8;
rval|= (*src++)<<8;
lval|= (*src++)<<16;
rval|= (*src++)<<16;
lval|= (*src++)<<24;
rval|= (*src++)<<24;
g2_write_32(left++,lval);
g2_write_32(right++,rval);
g2_fifo_wait();
}
}
static void spu_memload_stereo16(int leftpos,int rightpos,void *src0,size_t size)
{
uint16 *src = src0;
uint32 *left = (uint32*)(leftpos +SPU_RAM_BASE);
uint32 *right = (uint32*)(rightpos+SPU_RAM_BASE);
size = (size+7)/8;
while(size--) {
unsigned lval,rval;
lval = *src++;
rval = *src++;
lval|= (*src++)<<16;
rval|= (*src++)<<16;
g2_write_32(left++,lval);
g2_write_32(right++,rval);
g2_fifo_wait();
}
}
static void DCAUD_PlayAudio(_THIS)
{
SDL_AudioSpec *spec = &this->spec;
unsigned int offset;
if (this->hidden->playing) {
/* wait */
while(aica_get_pos(0)/spec->samples == this->hidden->nextbuf) {
thd_pass();
}
}
offset = this->hidden->nextbuf*spec->size;
this->hidden->nextbuf^=1;
/* Write the audio data, checking for EAGAIN on broken audio drivers */
if (spec->channels==1) {
spu_memload(this->hidden->leftpos+offset,this->hidden->mixbuf,this->hidden->mixlen);
} else {
offset/=2;
if ((this->spec.format&255)==8) {
spu_memload_stereo8(this->hidden->leftpos+offset,this->hidden->rightpos+offset,this->hidden->mixbuf,this->hidden->mixlen);
} else {
spu_memload_stereo16(this->hidden->leftpos+offset,this->hidden->rightpos+offset,this->hidden->mixbuf,this->hidden->mixlen);
}
}
if (!this->hidden->playing) {
int mode;
this->hidden->playing = 1;
mode = (spec->format==AUDIO_S8)?SM_8BIT:SM_16BIT;
if (spec->channels==1) {
aica_play(0,mode,this->hidden->leftpos,0,spec->samples*2,spec->freq,255,128,1);
} else {
aica_play(0,mode,this->hidden->leftpos ,0,spec->samples*2,spec->freq,255,0,1);
aica_play(1,mode,this->hidden->rightpos,0,spec->samples*2,spec->freq,255,255,1);
}
}
}
static Uint8 *DCAUD_GetAudioBuf(_THIS)
{
return(this->hidden->mixbuf);
}
static void DCAUD_CloseAudio(_THIS)
{
aica_stop(0);
if (this->spec.channels==2) aica_stop(1);
if ( this->hidden->mixbuf != NULL ) {
SDL_FreeAudioMem(this->hidden->mixbuf);
this->hidden->mixbuf = NULL;
}
}
static int DCAUD_OpenAudio(_THIS, SDL_AudioSpec *spec)
{
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Uint16 test_format = SDL_FirstAudioFormat(spec->format);
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int valid_datatype = 0;
while ((!valid_datatype) && (test_format)) {
spec->format = test_format;
switch (test_format) {
/* only formats Dreamcast accepts... */
case AUDIO_S8:
case AUDIO_S16LSB:
valid_datatype = 1;
break;
default:
test_format = SDL_NextAudioFormat();
break;
}
}
if (!valid_datatype) { /* shouldn't happen, but just in case... */
SDL_SetError("Unsupported audio format");
return (-1);
}
if (spec->channels > 2)
spec->channels = 2; /* no more than stereo on the Dreamcast. */
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/* Update the fragment size as size in bytes */
SDL_CalculateAudioSpec(spec);
/* Allocate mixing buffer */
this->hidden->mixlen = spec->size;
this->hidden->mixbuf = (Uint8 *) SDL_AllocAudioMem(this->hidden->mixlen);
if ( this->hidden->mixbuf == NULL ) {
return(-1);
}
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SDL_memset(this->hidden->mixbuf, spec->silence, spec->size);
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this->hidden->leftpos = 0x11000;
this->hidden->rightpos = 0x11000+spec->size;
this->hidden->playing = 0;
this->hidden->nextbuf = 0;
/* We're ready to rock and roll. :-) */
return(0);
}