1/*
2    SDL - Simple DirectMedia Layer
3    Copyright (C) 1997-2012 Sam Lantinga
4
5    This library is free software; you can redistribute it and/or
6    modify it under the terms of the GNU Library General Public
7    License as published by the Free Software Foundation; either
8    version 2 of the License, or (at your option) any later version.
9
10    This library is distributed in the hope that it will be useful,
11    but WITHOUT ANY WARRANTY; without even the implied warranty of
12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13    Library General Public License for more details.
14
15    You should have received a copy of the GNU Library General Public
16    License along with this library; if not, write to the Free
17    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
18
19    Sam Lantinga
20    slouken@libsdl.org
21*/
22#include "SDL_config.h"
23
24/*
25	Audio interrupt variables and callback function
26
27	Patrice Mandin
28*/
29
30#include <unistd.h>
31
32#include <mint/osbind.h>
33#include <mint/falcon.h>
34#include <mint/mintbind.h>
35#include <mint/cookie.h>
36
37#include "SDL_audio.h"
38#include "SDL_mintaudio.h"
39#include "SDL_mintaudio_stfa.h"
40
41/* The audio device */
42
43SDL_AudioDevice *SDL_MintAudio_device;
44Uint8 *SDL_MintAudio_audiobuf[2];	/* Pointers to buffers */
45unsigned long SDL_MintAudio_audiosize;		/* Length of audio buffer=spec->size */
46volatile unsigned short SDL_MintAudio_numbuf;		/* Buffer to play */
47volatile unsigned short SDL_MintAudio_mutex;
48volatile unsigned long SDL_MintAudio_clocktics;
49cookie_stfa_t	*SDL_MintAudio_stfa;
50unsigned short SDL_MintAudio_hasfpu;
51
52/* MiNT thread variables */
53SDL_bool SDL_MintAudio_mint_present;
54SDL_bool SDL_MintAudio_quit_thread;
55SDL_bool SDL_MintAudio_thread_finished;
56long SDL_MintAudio_thread_pid;
57
58/* The callback function, called by each driver whenever needed */
59
60void SDL_MintAudio_Callback(void)
61{
62	Uint8 *buffer;
63	SDL_AudioDevice *audio = SDL_MintAudio_device;
64
65 	buffer = SDL_MintAudio_audiobuf[SDL_MintAudio_numbuf];
66	SDL_memset(buffer, audio->spec.silence, audio->spec.size);
67
68	if (audio->paused)
69		return;
70
71	if (audio->convert.needed) {
72		int silence;
73
74		if ( audio->convert.src_format == AUDIO_U8 ) {
75			silence = 0x80;
76		} else {
77			silence = 0;
78		}
79		SDL_memset(audio->convert.buf, silence, audio->convert.len);
80		audio->spec.callback(audio->spec.userdata,
81			(Uint8 *)audio->convert.buf,audio->convert.len);
82		SDL_ConvertAudio(&audio->convert);
83		SDL_memcpy(buffer, audio->convert.buf, audio->convert.len_cvt);
84	} else {
85		audio->spec.callback(audio->spec.userdata, buffer, audio->spec.size);
86	}
87}
88
89/* Add a new frequency/clock/predivisor to the current list */
90void SDL_MintAudio_AddFrequency(_THIS, Uint32 frequency, Uint32 clock,
91	Uint32 prediv, int gpio_bits)
92{
93	int i, p;
94
95	if (MINTAUDIO_freqcount==MINTAUDIO_maxfreqs) {
96		return;
97	}
98
99	/* Search where to insert the frequency (highest first) */
100	for (p=0; p<MINTAUDIO_freqcount; p++) {
101		if (frequency > MINTAUDIO_frequencies[p].frequency) {
102			break;
103		}
104	}
105
106	/* Put all following ones farer */
107	if (MINTAUDIO_freqcount>0) {
108		for (i=MINTAUDIO_freqcount; i>p; i--) {
109			SDL_memcpy(&MINTAUDIO_frequencies[i], &MINTAUDIO_frequencies[i-1], sizeof(mint_frequency_t));
110		}
111	}
112
113	/* And insert new one */
114	MINTAUDIO_frequencies[p].frequency = frequency;
115	MINTAUDIO_frequencies[p].masterclock = clock;
116	MINTAUDIO_frequencies[p].predivisor = prediv;
117	MINTAUDIO_frequencies[p].gpio_bits = gpio_bits;
118
119	MINTAUDIO_freqcount++;
120}
121
122/* Search for the nearest frequency */
123int SDL_MintAudio_SearchFrequency(_THIS, int desired_freq)
124{
125	int i;
126
127	/* Only 1 freq ? */
128	if (MINTAUDIO_freqcount==1) {
129		return 0;
130	}
131
132	/* Check the array */
133	for (i=0; i<MINTAUDIO_freqcount; i++) {
134		if (desired_freq >= ((MINTAUDIO_frequencies[i].frequency+
135			MINTAUDIO_frequencies[i+1].frequency)>>1)) {
136			return i;
137		}
138	}
139
140	/* Not in the array, give the latest */
141	return MINTAUDIO_freqcount-1;
142}
143
144/* Check if FPU is present */
145void SDL_MintAudio_CheckFpu(void)
146{
147	long cookie_fpu;
148
149	SDL_MintAudio_hasfpu = 0;
150	if (Getcookie(C__FPU, &cookie_fpu) != C_FOUND) {
151		return;
152	}
153	switch ((cookie_fpu>>16)&0xfffe) {
154		case 2:
155		case 4:
156		case 6:
157		case 8:
158		case 16:
159			SDL_MintAudio_hasfpu = 1;
160			break;
161	}
162}
163
164/* The thread function, used under MiNT with xbios */
165int SDL_MintAudio_Thread(long param)
166{
167	SndBufPtr	pointers;
168	SDL_bool	buffers_filled[2] = {SDL_FALSE, SDL_FALSE};
169
170	SDL_MintAudio_thread_finished = SDL_FALSE;
171	while (!SDL_MintAudio_quit_thread) {
172		if (Buffptr(&pointers)!=0)
173			continue;
174
175		if (( (unsigned long)pointers.play>=(unsigned long)SDL_MintAudio_audiobuf[0])
176			&& ( (unsigned long)pointers.play<=(unsigned long)SDL_MintAudio_audiobuf[1]))
177		{
178			/* DMA is reading buffer #0, setup buffer #1 if not already done */
179			if (!buffers_filled[1]) {
180				SDL_MintAudio_numbuf = 1;
181				SDL_MintAudio_Callback();
182				Setbuffer(0, SDL_MintAudio_audiobuf[1], SDL_MintAudio_audiobuf[1] + SDL_MintAudio_audiosize);
183				buffers_filled[1]=SDL_TRUE;
184				buffers_filled[0]=SDL_FALSE;
185			}
186		} else {
187			/* DMA is reading buffer #1, setup buffer #0 if not already done */
188			if (!buffers_filled[0]) {
189				SDL_MintAudio_numbuf = 0;
190				SDL_MintAudio_Callback();
191				Setbuffer(0, SDL_MintAudio_audiobuf[0], SDL_MintAudio_audiobuf[0] + SDL_MintAudio_audiosize);
192				buffers_filled[0]=SDL_TRUE;
193				buffers_filled[1]=SDL_FALSE;
194			}
195		}
196
197		usleep(100);
198	}
199	SDL_MintAudio_thread_finished = SDL_TRUE;
200	return 0;
201}
202
203void SDL_MintAudio_WaitThread(void)
204{
205	if (!SDL_MintAudio_mint_present)
206		return;
207
208	if (SDL_MintAudio_thread_finished)
209		return;
210
211	SDL_MintAudio_quit_thread = SDL_TRUE;
212	while (!SDL_MintAudio_thread_finished) {
213		Syield();
214	}
215}
216