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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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*/
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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 */
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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);
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/* Audio driver bootstrap functions */
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static int
DCAUD_Available (void)
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{
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return 1;
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}
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static void
DCAUD_DeleteDevice (SDL_AudioDevice * device)
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{
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SDL_free (device->hidden);
SDL_free (device);
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}
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static SDL_AudioDevice *
DCAUD_CreateDevice (int devindex)
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{
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SDL_AudioDevice *this;
/* Initialize all variables that we clean on shutdown */
this = (SDL_AudioDevice *) SDL_malloc (sizeof (SDL_AudioDevice));
if (this) {
SDL_memset (this, 0, (sizeof *this));
this->hidden = (struct SDL_PrivateAudioData *)
SDL_malloc ((sizeof *this->hidden));
}
if ((this == NULL) || (this->hidden == NULL)) {
SDL_OutOfMemory ();
if (this) {
SDL_free (this);
}
return (0);
}
SDL_memset (this->hidden, 0, (sizeof *this->hidden));
/* 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;
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}
AudioBootStrap DCAUD_bootstrap = {
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"dcaudio", "Dreamcast AICA audio",
DCAUD_Available, DCAUD_CreateDevice
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};
/* This function waits until it is possible to write a full sound buffer */
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static void
DCAUD_WaitAudio (_THIS)
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{
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if (this->hidden->playing) {
/* wait */
while (aica_get_pos (0) / this->spec.samples == this->hidden->nextbuf) {
thd_pass ();
}
}
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}
#define SPU_RAM_BASE 0xa0800000
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static void
spu_memload_stereo8 (int leftpos, int rightpos, void *src0, size_t size)
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{
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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 ();
}
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}
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static void
spu_memload_stereo16 (int leftpos, int rightpos, void *src0, size_t size)
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{
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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 ();
}
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}
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static void
DCAUD_PlayAudio (_THIS)
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{
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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);
}
}
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}
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static Uint8 *
DCAUD_GetAudioBuf (_THIS)
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{
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return (this->hidden->mixbuf);
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}
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static void
DCAUD_CloseAudio (_THIS)
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{
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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;
}
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}
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static int
DCAUD_OpenAudio (_THIS, SDL_AudioSpec * spec)
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{
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switch (spec->format & 0xff) {
case 8:
spec->format = AUDIO_S8;
break;
case 16:
spec->format = AUDIO_S16LSB;
break;
default:
SDL_SetError ("Unsupported audio format");
return (-1);
}
/* 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);
}
SDL_memset (this->hidden->mixbuf, spec->silence, spec->size);
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);
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}
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/* vi: set ts=4 sw=4 expandtab: */