293 lines
8.1 KiB
C
293 lines
8.1 KiB
C
/*
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SDL - Simple DirectMedia Layer
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Copyright (C) 1997, 1998, 1999, 2000, 2001 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 Library General Public
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License as published by the Free Software Foundation; either
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version 2 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,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with this library; if not, write to the Free
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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Sam Lantinga
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slouken@devolution.com
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*/
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#include <stdlib.h>
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#include <stdio.h>
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#include <memory.h>
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#include <kernel.h>
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#include "swis.h"
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#include "SDL_endian.h"
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#include "SDL_audio.h"
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#include "SDL_audio_c.h"
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#include "SDL_audiomem.h"
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#include "SDL_sysaudio.h"
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#include "SDL_drenderer.h"
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#define DigitalRenderer_Activate 0x4F700
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#define DigitalRenderer_Deactivate 0x4F701
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#define DigitalRenderer_ReadState 0x4F705
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#define DigitalRenderer_NewSample 0x4F706
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#define DigitalRenderer_NumBuffers 0x4F709
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#define DigitalRenderer_StreamSamples 0x4F70A
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#define DigitalRenderer_Stream16BitSamples 0x4F70B
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#define DigitalRenderer_StreamStatistics 0x4F70C
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#define DigitalRenderer_StreamFlags 0x4F70D
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#define DigitalRenderer_Activate16 0x4F70F
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#define DigitalRenderer_GetFrequency 0x4F710
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static int FillBuffer;
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extern SDL_AudioDevice *current_audio;
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extern int riscos_audiobuffer; /* Override for audio buffer size */
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/* Audio driver functions */
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static void DRenderer_CloseAudio(_THIS);
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static int DRenderer_OpenAudio(_THIS, SDL_AudioSpec *spec);
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/* Audio driver bootstrap functions */
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/* Define following to dump stats to stdout */
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/* #define DUMP_AUDIO */
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static int Audio_Available(void)
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{
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_kernel_swi_regs regs;
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int available = 0;
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/* Use call to set buffers to also check if Module is loaded */
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regs.r[0] = 0;
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if (_kernel_swi(DigitalRenderer_NumBuffers, ®s, ®s) == 0) available = 1;
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return(available);
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}
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static void Audio_DeleteDevice(SDL_AudioDevice *device)
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{
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free(device->hidden);
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free(device);
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}
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static SDL_AudioDevice *Audio_CreateDevice(int devindex)
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{
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SDL_AudioDevice *this;
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/* Initialize all variables that we clean on shutdown */
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this = (SDL_AudioDevice *)malloc(sizeof(SDL_AudioDevice));
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if ( this ) {
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memset(this, 0, (sizeof *this));
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this->hidden = (struct SDL_PrivateAudioData *)
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malloc((sizeof *this->hidden));
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}
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if ( (this == NULL) || (this->hidden == NULL) ) {
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SDL_OutOfMemory();
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if ( this ) {
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free(this);
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}
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return(0);
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}
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memset(this->hidden, 0, (sizeof *this->hidden));
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/* Set the function pointers */
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this->OpenAudio = DRenderer_OpenAudio;
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this->CloseAudio = DRenderer_CloseAudio;
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this->free = Audio_DeleteDevice;
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return this;
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}
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AudioBootStrap DRENDERER_bootstrap = {
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"drenderer", "RiscOS Digital Renderer Module",
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Audio_Available, Audio_CreateDevice
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};
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/* Routine called to check and fill audio buffers if necessary */
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static Uint8 *buffer = NULL;
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void DRenderer_FillBuffers()
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{
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SDL_AudioDevice *audio = current_audio;
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if ( !audio || ! audio->enabled )
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{
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return;
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}
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if ( ! audio->paused )
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{
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_kernel_swi_regs regs;
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/* Check filled buffers count */
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_kernel_swi(DigitalRenderer_StreamStatistics, ®s, ®s);
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#ifdef DUMP_AUDIO
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if (regs.r[0] <= FillBuffer)
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{
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printf("Buffers in use %d\n", regs.r[0]);
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}
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#endif
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while (regs.r[0] <= FillBuffer && !audio->paused)
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{
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if ( audio->convert.needed )
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{
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int silence;
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if ( audio->convert.src_format == AUDIO_U8 )
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{
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silence = 0x80;
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} else {
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silence = 0;
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}
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memset(audio->convert.buf, silence, audio->convert.len);
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audio->spec.callback(audio->spec.userdata,
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(Uint8 *)audio->convert.buf,audio->convert.len);
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SDL_ConvertAudio(&audio->convert);
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#if 0
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if ( audio->convert.len_cvt != audio->spec.size ) {
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/* Uh oh... probably crashes here; */
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}
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#endif
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regs.r[0] = (int)audio->convert.buf;
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regs.r[1] = audio->spec.samples * audio->spec.channels;
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_kernel_swi(DigitalRenderer_Stream16BitSamples, ®s, ®s);
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} else
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{
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/* Fill buffer with silence */
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memset (buffer, 0, audio->spec.size);
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audio->spec.callback(audio->spec.userdata,
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(Uint8 *)buffer, audio->spec.size);
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regs.r[0] = (int)buffer;
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regs.r[1] = audio->spec.samples * audio->spec.channels;
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_kernel_swi(DigitalRenderer_Stream16BitSamples, ®s, ®s);
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}
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/* Check if we have enough buffers yet */
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_kernel_swi(DigitalRenderer_StreamStatistics, ®s, ®s);
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}
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}
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}
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/* Size of DMA buffer to use */
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#define DRENDERER_BUFFER_SIZE 512
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/* Number of centiseconds of sound to buffer.
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Hopefully more than the maximum time between calls to the
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FillBuffers routine above
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*/
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#define DRENDERER_CSEC_TO_BUFFER 10
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static int DRenderer_OpenAudio(_THIS, SDL_AudioSpec *spec)
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{
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_kernel_swi_regs regs;
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int buffers_per_sample;
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#ifdef DUMP_AUDIO
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printf("Request format %d\n", spec->format);
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printf("Request freq %d\n", spec->freq);
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printf("Samples %d\n", spec->samples);
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#endif
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/* Only support signed 16bit format */
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spec->format = AUDIO_S16LSB;
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if (spec->samples < DRENDERER_BUFFER_SIZE) spec->samples = DRENDERER_BUFFER_SIZE;
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SDL_CalculateAudioSpec(spec);
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buffers_per_sample = spec->samples / DRENDERER_BUFFER_SIZE;
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if ((spec->samples % DRENDERER_BUFFER_SIZE) != 0)
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{
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buffers_per_sample++;
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spec->samples = buffers_per_sample * DRENDERER_BUFFER_SIZE;
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}
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/* Set number of buffers to use - the following should give enough
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data between calls to the sound polling.
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*/
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if (riscos_audiobuffer == 0)
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{
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FillBuffer = (int)((double)DRENDERER_CSEC_TO_BUFFER / ((double)DRENDERER_BUFFER_SIZE * 100.0 / (double)spec->freq)) + 1;
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} else FillBuffer = riscos_audiobuffer/DRENDERER_BUFFER_SIZE - buffers_per_sample;
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if (FillBuffer < buffers_per_sample) FillBuffer = buffers_per_sample;
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regs.r[0] = FillBuffer + buffers_per_sample;
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#ifdef DUMP_AUDIO
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printf("Buffers per sample %d\n", buffers_per_sample);
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printf("Fill buffer %d\n", FillBuffer);
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printf("Time buffered (ms) %d\n",(int)((1000.0 * regs.r[0] * DRENDERER_BUFFER_SIZE)/(double)spec->freq));
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#endif
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if (_kernel_swi(DigitalRenderer_NumBuffers, ®s, ®s) != 0)
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{
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SDL_SetError("Can't set number of streaming sound buffers\n");
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return -1;
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}
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/* Now initialise sound system */
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regs.r[0] = spec->channels; /* Number of channels */
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regs.r[1] = DRENDERER_BUFFER_SIZE; /* Samples length */
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regs.r[2] = spec->freq; /* frequency */
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regs.r[3] = 1; /* Restore previous handler on exit */
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if (_kernel_swi(DigitalRenderer_Activate16, ®s, ®s) != 0)
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{
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SDL_SetError("Unable to activate digital renderer in 16 bit mode\n");
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return -1;
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}
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if (_kernel_swi(DigitalRenderer_GetFrequency, ®s, ®s) == 0)
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{
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spec->freq = regs.r[0];
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}
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#ifdef DUMP_AUDIO
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printf("Got format %d\n", spec->format);
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printf("Frequency %d\n", spec->freq);
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printf("Samples %d\n", spec->samples);
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#endif
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/* Set to fill buffer with zero if we don't get data to it fast enough */
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regs.r[0] = 1;
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regs.r[1] = ~1;
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_kernel_swi(DigitalRenderer_StreamFlags, ®s, ®s);
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buffer = (Uint8 *)malloc(sizeof(Uint8) * spec->size);
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if (buffer == NULL)
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{
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SDL_OutOfMemory();
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return -1;
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}
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/* Hopefully returning 2 will show success, but not start up an audio thread */
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return 2;
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}
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static void DRenderer_CloseAudio(_THIS)
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{
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_kernel_swi_regs regs;
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/* Close down the digital renderer */
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_kernel_swi(DigitalRenderer_Deactivate, ®s, ®s);
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if (buffer != NULL) free(buffer);
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}
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