/*

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_mintaudio.h"

#include "SDL_mintaudio_stfa.h"

/* The audio device */

SDL_AudioDevice *SDL_MintAudio_device;

Uint8 *SDL_MintAudio_audiobuf[2]; /* Pointers to buffers */

unsigned long SDL_MintAudio_audiosize; /* Length of audio buffer=spec->size */

volatile unsigned short SDL_MintAudio_numbuf; /* Buffer to play */

volatile unsigned short SDL_MintAudio_mutex;

volatile unsigned long SDL_MintAudio_clocktics;

cookie_stfa_t *SDL_MintAudio_stfa;

unsigned short SDL_MintAudio_hasfpu;

/* 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;

/* The callback function, called by each driver whenever needed */

void SDL_MintAudio_Callback(void)

{

Uint8 *buffer;

SDL_AudioDevice *audio = SDL_MintAudio_device;

buffer = SDL_MintAudio_audiobuf[SDL_MintAudio_numbuf];

SDL_memset(buffer, audio->spec.silence, audio->spec.size);

if (audio->paused)

return;

if (audio->convert.needed) {

int silence;

if ( audio->convert.src_format == AUDIO_U8 ) {

silence = 0x80;

} else {

silence = 0;

}

SDL_memset(audio->convert.buf, silence, audio->convert.len);

audio->spec.callback(audio->spec.userdata,

(Uint8 *)audio->convert.buf,audio->convert.len);

SDL_ConvertAudio(&audio->convert);

SDL_memcpy(buffer, audio->convert.buf, audio->convert.len_cvt);

} else {

audio->spec.callback(audio->spec.userdata, buffer, audio->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;

}

/* Check if FPU is present */

void SDL_MintAudio_CheckFpu(void)

{

long cookie_fpu;

SDL_MintAudio_hasfpu = 0;

if (Getcookie(C__FPU, &cookie_fpu) != C_FOUND) {

return;

}

switch ((cookie_fpu>>16)&0xfffe) {

case 2:

case 4:

case 6:

case 8:

case 16:

SDL_MintAudio_hasfpu = 1;

break;

}

}

/* 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_MintAudio_thread_finished = SDL_FALSE;

while (!SDL_MintAudio_quit_thread) {

if (Buffptr(&pointers)!=0)

continue;

if (( (unsigned long)pointers.play>=(unsigned long)SDL_MintAudio_audiobuf[0])

&& ( (unsigned long)pointers.play<=(unsigned long)SDL_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, SDL_MintAudio_audiobuf[1], SDL_MintAudio_audiobuf[1] + SDL_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, SDL_MintAudio_audiobuf[0], SDL_MintAudio_audiobuf[0] + SDL_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();

}

}