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SDL_mintaudio.c
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SDL_mintaudio.c
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/*
SDL - Simple DirectMedia Layer
Copyright (C) 1997-2012 Sam Lantinga
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.
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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with this library; if not, write to the Free
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
Sam Lantinga
slouken@libsdl.org
*/
#include "SDL_config.h"
/*
Audio interrupt variables and callback function
Patrice Mandin
*/
#include <unistd.h>
#include <mint/osbind.h>
#include <mint/falcon.h>
#include <mint/mintbind.h>
#include <mint/cookie.h>
#include "SDL_audio.h"
#include "../SDL_audio_c.h"
#include "../SDL_sysaudio.h"
#include "../../video/ataricommon/SDL_atarimxalloc_c.h"
#include "SDL_mintaudio.h"
/* The audio device */
#define MAX_DMA_BUF 8
SDL_AudioDevice *SDL_MintAudio_device;
static int SDL_MintAudio_num_upd; /* Number of calls to update function */
static int SDL_MintAudio_max_buf; /* Number of buffers to use */
static int SDL_MintAudio_numbuf; /* Buffer to play */
static void SDL_MintAudio_Callback(void);
/* MiNT thread variables */
SDL_bool SDL_MintAudio_mint_present;
SDL_bool SDL_MintAudio_quit_thread;
SDL_bool SDL_MintAudio_thread_finished;
long SDL_MintAudio_thread_pid;
/* Debug print info */
#define DEBUG_NAME "audio:mint: "
#if 0
#define DEBUG_PRINT(what) \
{ \
printf what; \
}
#else
#define DEBUG_PRINT(what)
#endif
/* Initialize DMA buffers */
int SDL_MintAudio_InitBuffers(SDL_AudioSpec *spec)
{
SDL_AudioDevice *this = SDL_MintAudio_device;
SDL_CalculateAudioSpec(spec);
MINTAUDIO_audiosize = spec->size * MAX_DMA_BUF;
/* Allocate memory for audio buffers in DMA-able RAM */
MINTAUDIO_audiobuf[0] = Atari_SysMalloc(2 * MINTAUDIO_audiosize, MX_STRAM);
if (MINTAUDIO_audiobuf[0]==NULL) {
SDL_SetError("SDL_MintAudio_OpenAudio: Not enough memory for audio buffer");
return (0);
}
MINTAUDIO_audiobuf[1] = MINTAUDIO_audiobuf[0] + MINTAUDIO_audiosize;
SDL_memset(MINTAUDIO_audiobuf[0], spec->silence, 2 * MINTAUDIO_audiosize);
DEBUG_PRINT((DEBUG_NAME "buffer 0 at 0x%p\n", MINTAUDIO_audiobuf[0]));
DEBUG_PRINT((DEBUG_NAME "buffer 1 at 0x%p\n", MINTAUDIO_audiobuf[1]));
SDL_MintAudio_numbuf = SDL_MintAudio_num_its = SDL_MintAudio_num_upd = 0;
SDL_MintAudio_max_buf = MAX_DMA_BUF;
return (1);
}
/* Destroy DMA buffers */
void SDL_MintAudio_FreeBuffers(void)
{
SDL_AudioDevice *this = SDL_MintAudio_device;
if (MINTAUDIO_audiobuf[0]) {
Mfree(MINTAUDIO_audiobuf[0]);
MINTAUDIO_audiobuf[0] = MINTAUDIO_audiobuf[1] = NULL;
}
}
/* Update buffers */
void SDL_AtariMint_UpdateAudio(void)
{
SDL_AudioDevice *this = SDL_MintAudio_device;
++SDL_MintAudio_num_upd;
/* No interrupt triggered? still playing current buffer */
if (SDL_MintAudio_num_its==0) {
return;
}
if (SDL_MintAudio_num_upd < (SDL_MintAudio_num_its<<2)) {
/* Too many interrupts per update, increase latency */
if (SDL_MintAudio_max_buf < MAX_DMA_BUF) {
SDL_MintAudio_max_buf <<= 1;
}
} else if (SDL_MintAudio_num_its < (SDL_MintAudio_num_upd<<2)) {
/* Too many updates per interrupt, decrease latency */
if (SDL_MintAudio_max_buf > 1) {
SDL_MintAudio_max_buf >>= 1;
}
}
MINTAUDIO_audiosize = this->spec.size * SDL_MintAudio_max_buf;
SDL_MintAudio_num_its = 0;
SDL_MintAudio_num_upd = 0;
SDL_MintAudio_numbuf ^= 1;
/* Fill new buffer */
SDL_MintAudio_Callback();
/* And swap to it */
(*MINTAUDIO_swapbuf)(MINTAUDIO_audiobuf[SDL_MintAudio_numbuf], MINTAUDIO_audiosize);
}
/* The callback function, called by each driver whenever needed */
static void SDL_MintAudio_Callback(void)
{
SDL_AudioDevice *this = SDL_MintAudio_device;
Uint8 *buffer;
int i;
buffer = MINTAUDIO_audiobuf[SDL_MintAudio_numbuf];
SDL_memset(buffer, this->spec.silence, this->spec.size * SDL_MintAudio_max_buf);
if (this->paused)
return;
for (i=0; i<SDL_MintAudio_max_buf; i++) {
if (this->convert.needed) {
int silence;
if ( this->convert.src_format == AUDIO_U8 ) {
silence = 0x80;
} else {
silence = 0;
}
SDL_memset(this->convert.buf, silence, this->convert.len);
this->spec.callback(this->spec.userdata,
(Uint8 *)this->convert.buf,this->convert.len);
SDL_ConvertAudio(&this->convert);
SDL_memcpy(buffer, this->convert.buf, this->convert.len_cvt);
buffer += this->convert.len_cvt;
} else {
this->spec.callback(this->spec.userdata, buffer, this->spec.size);
buffer += this->spec.size;
}
}
}
/* Add a new frequency/clock/predivisor to the current list */
void SDL_MintAudio_AddFrequency(_THIS, Uint32 frequency, Uint32 clock,
Uint32 prediv, int gpio_bits)
{
int i, p;
if (MINTAUDIO_freqcount==MINTAUDIO_maxfreqs) {
return;
}
/* Search where to insert the frequency (highest first) */
for (p=0; p<MINTAUDIO_freqcount; p++) {
if (frequency > MINTAUDIO_frequencies[p].frequency) {
break;
}
}
/* Put all following ones farer */
if (MINTAUDIO_freqcount>0) {
for (i=MINTAUDIO_freqcount; i>p; i--) {
SDL_memcpy(&MINTAUDIO_frequencies[i], &MINTAUDIO_frequencies[i-1], sizeof(mint_frequency_t));
}
}
/* And insert new one */
MINTAUDIO_frequencies[p].frequency = frequency;
MINTAUDIO_frequencies[p].masterclock = clock;
MINTAUDIO_frequencies[p].predivisor = prediv;
MINTAUDIO_frequencies[p].gpio_bits = gpio_bits;
MINTAUDIO_freqcount++;
}
/* Search for the nearest frequency */
int SDL_MintAudio_SearchFrequency(_THIS, int desired_freq)
{
int i;
/* Only 1 freq ? */
if (MINTAUDIO_freqcount==1) {
return 0;
}
/* Check the array */
for (i=0; i<MINTAUDIO_freqcount; i++) {
if (desired_freq >= ((MINTAUDIO_frequencies[i].frequency+
MINTAUDIO_frequencies[i+1].frequency)>>1)) {
return i;
}
}
/* Not in the array, give the latest */
return MINTAUDIO_freqcount-1;
}
/* The thread function, used under MiNT with xbios */
int SDL_MintAudio_Thread(long param)
{
SndBufPtr pointers;
SDL_bool buffers_filled[2] = {SDL_FALSE, SDL_FALSE};
SDL_AudioDevice *this = SDL_MintAudio_device;
SDL_MintAudio_thread_finished = SDL_FALSE;
while (!SDL_MintAudio_quit_thread) {
if (Buffptr(&pointers)!=0)
continue;
if (( (unsigned long)pointers.play>=(unsigned long)MINTAUDIO_audiobuf[0])
&& ( (unsigned long)pointers.play<=(unsigned long)MINTAUDIO_audiobuf[1]))
{
/* DMA is reading buffer #0, setup buffer #1 if not already done */
if (!buffers_filled[1]) {
SDL_MintAudio_numbuf = 1;
SDL_MintAudio_Callback();
Setbuffer(0, MINTAUDIO_audiobuf[1], MINTAUDIO_audiobuf[1] + MINTAUDIO_audiosize);
buffers_filled[1]=SDL_TRUE;
buffers_filled[0]=SDL_FALSE;
}
} else {
/* DMA is reading buffer #1, setup buffer #0 if not already done */
if (!buffers_filled[0]) {
SDL_MintAudio_numbuf = 0;
SDL_MintAudio_Callback();
Setbuffer(0, MINTAUDIO_audiobuf[0], MINTAUDIO_audiobuf[0] + MINTAUDIO_audiosize);
buffers_filled[0]=SDL_TRUE;
buffers_filled[1]=SDL_FALSE;
}
}
usleep(100);
}
SDL_MintAudio_thread_finished = SDL_TRUE;
return 0;
}
void SDL_MintAudio_WaitThread(void)
{
if (!SDL_MintAudio_mint_present)
return;
if (SDL_MintAudio_thread_finished)
return;
SDL_MintAudio_quit_thread = SDL_TRUE;
while (!SDL_MintAudio_thread_finished) {
Syield();
}
}