SDL_mintaudio.c
2
SDL - Simple DirectMedia Layer
3
Copyright (C) 1997-2012 Sam Lantinga
5
6
7
8
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.
10
11
12
13
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.
15
16
17
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
19
20
21
Sam Lantinga
slouken@libsdl.org
*/
22
#include "SDL_config.h"
24
25
/*
Audio interrupt variables and callback function
27
28
Patrice Mandin
*/
30
31
32
33
34
#include <unistd.h>
#include <mint/osbind.h>
#include <mint/falcon.h>
#include <mint/mintbind.h>
35
#include <mint/cookie.h>
37
#include "SDL_audio.h"
38
39
40
41
42
#include "../SDL_audio_c.h"
#include "../SDL_sysaudio.h"
#include "../../video/ataricommon/SDL_atarimxalloc_c.h"
43
#include "SDL_mintaudio.h"
45
/* The audio device */
47
48
#define MAX_DMA_BUF 8
49
SDL_AudioDevice *SDL_MintAudio_device;
50
51
52
53
54
55
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);
57
58
59
60
61
62
/* 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;
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
/* 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)
{
78
int dmabuflen;
79
80
81
82
83
SDL_AudioDevice *this = SDL_MintAudio_device;
SDL_CalculateAudioSpec(spec);
MINTAUDIO_audiosize = spec->size * MAX_DMA_BUF;
84
85
86
87
88
89
90
/* Allocate audio buffer memory for application in FastRAM */
MINTAUDIO_fastrambuf = Atari_SysMalloc(MINTAUDIO_audiosize, MX_TTRAM);
if (MINTAUDIO_fastrambuf) {
SDL_memset(MINTAUDIO_fastrambuf, spec->silence, MINTAUDIO_audiosize);
}
/* Allocate audio buffers memory for hardware in DMA-able RAM */
91
92
dmabuflen = ((2 * MINTAUDIO_audiosize) | 3)+1;
MINTAUDIO_audiobuf[0] = Atari_SysMalloc(dmabuflen, MX_STRAM);
93
94
95
96
97
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;
98
SDL_memset(MINTAUDIO_audiobuf[0], spec->silence, dmabuflen);
99
100
101
102
103
104
105
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;
106
107
108
109
110
111
/* For filling silence when too many interrupts per update */
SDL_MintAudio_itbuffer = MINTAUDIO_audiobuf[0];
SDL_MintAudio_itbuflen = (dmabuflen >> 2)-1;
SDL_MintAudio_itsilence = (spec->silence << 24)|(spec->silence << 16)|
(spec->silence << 8)|spec->silence;
112
113
114
115
116
117
118
119
120
return (1);
}
/* Destroy DMA buffers */
void SDL_MintAudio_FreeBuffers(void)
{
SDL_AudioDevice *this = SDL_MintAudio_device;
121
122
123
124
if (MINTAUDIO_fastrambuf) {
Mfree(MINTAUDIO_fastrambuf);
MINTAUDIO_fastrambuf = NULL;
}
125
126
if (MINTAUDIO_audiobuf[0]) {
Mfree(MINTAUDIO_audiobuf[0]);
127
SDL_MintAudio_itbuffer = MINTAUDIO_audiobuf[0] = MINTAUDIO_audiobuf[1] = NULL;
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
}
}
/* 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);
}
169
/* The callback function, called by each driver whenever needed */
171
static void SDL_MintAudio_Callback(void)
173
SDL_AudioDevice *this = SDL_MintAudio_device;
174
Uint8 *buffer;
177
178
179
buffer = (MINTAUDIO_fastrambuf ?
MINTAUDIO_fastrambuf :
MINTAUDIO_audiobuf[SDL_MintAudio_numbuf]);
180
SDL_memset(buffer, this->spec.silence, this->spec.size * SDL_MintAudio_max_buf);
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
if (!this->paused) {
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;
200
201
this->spec.callback(this->spec.userdata, buffer,
this->spec.size);
203
204
buffer += this->spec.size;
}
207
208
209
210
211
if (MINTAUDIO_fastrambuf) {
SDL_memcpy(MINTAUDIO_audiobuf[SDL_MintAudio_numbuf], MINTAUDIO_fastrambuf,
this->spec.size * SDL_MintAudio_max_buf);
}
214
/* Add a new frequency/clock/predivisor to the current list */
215
216
void SDL_MintAudio_AddFrequency(_THIS, Uint32 frequency, Uint32 clock,
Uint32 prediv, int gpio_bits)
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
{
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--) {
234
SDL_memcpy(&MINTAUDIO_frequencies[i], &MINTAUDIO_frequencies[i-1], sizeof(mint_frequency_t));
235
236
237
238
239
240
241
}
}
/* And insert new one */
MINTAUDIO_frequencies[p].frequency = frequency;
MINTAUDIO_frequencies[p].masterclock = clock;
MINTAUDIO_frequencies[p].predivisor = prediv;
242
MINTAUDIO_frequencies[p].gpio_bits = gpio_bits;
243
244
245
246
247
248
MINTAUDIO_freqcount++;
}
/* Search for the nearest frequency */
int SDL_MintAudio_SearchFrequency(_THIS, int desired_freq)
249
250
251
{
int i;
252
/* Only 1 freq ? */
253
254
if (MINTAUDIO_freqcount==1) {
return 0;
257
/* Check the array */
258
259
260
for (i=0; i<MINTAUDIO_freqcount; i++) {
if (desired_freq >= ((MINTAUDIO_frequencies[i].frequency+
MINTAUDIO_frequencies[i+1].frequency)>>1)) {
261
return i;
262
263
264
}
}
265
/* Not in the array, give the latest */
266
return MINTAUDIO_freqcount-1;
268
269
270
271
272
273
/* 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};
274
SDL_AudioDevice *this = SDL_MintAudio_device;
275
276
277
278
279
280
SDL_MintAudio_thread_finished = SDL_FALSE;
while (!SDL_MintAudio_quit_thread) {
if (Buffptr(&pointers)!=0)
continue;
281
282
if (( (unsigned long)pointers.play>=(unsigned long)MINTAUDIO_audiobuf[0])
&& ( (unsigned long)pointers.play<=(unsigned long)MINTAUDIO_audiobuf[1]))
283
284
285
286
287
{
/* DMA is reading buffer #0, setup buffer #1 if not already done */
if (!buffers_filled[1]) {
SDL_MintAudio_numbuf = 1;
SDL_MintAudio_Callback();
288
Setbuffer(0, MINTAUDIO_audiobuf[1], MINTAUDIO_audiobuf[1] + MINTAUDIO_audiosize);
289
290
291
292
293
294
295
296
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();
297
Setbuffer(0, MINTAUDIO_audiobuf[0], MINTAUDIO_audiobuf[0] + MINTAUDIO_audiosize);
298
299
300
301
302
buffers_filled[0]=SDL_TRUE;
buffers_filled[1]=SDL_FALSE;
}
}
303
usleep(100);
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
}
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();
}
}