-
Notifications
You must be signed in to change notification settings - Fork 4
/
sound.c
828 lines (699 loc) · 31.5 KB
/
sound.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
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
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
/* gameplaySP
*
* Copyright (C) 2006 Exophase <exophase@gmail.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* This program 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
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "common.h"
u32 global_enable_audio = 1;
direct_sound_struct direct_sound_channel[2];
gbc_sound_struct gbc_sound_channel[4];
#if defined(GP2X_BUILD) || defined(TAVI_BUILD) || defined(ZAURUS)
u32 sound_frequency = 44100;
#else
u32 sound_frequency = 22050;
#endif
SDL_AudioSpec sound_settings;
SDL_mutex *sound_mutex;
SDL_cond *sound_cv;
#ifndef PSP_BUILD
u32 audio_buffer_size_number = 0;
#else
u32 audio_buffer_size_number = 1;
#endif
u32 audio_buffer_size;
u32 sound_on = 0;
s16 sound_buffer[BUFFER_SIZE];
u32 sound_buffer_base = 0;
u32 sound_last_cpu_ticks = 0;
fixed16_16 gbc_sound_tick_step;
// Queue 1, 2, or 4 samples to the top of the DS FIFO, wrap around circularly
#define sound_timer_queue(size, value) \
*((s##size *)(ds->fifo + ds->fifo_top)) = value; \
ds->fifo_top = (ds->fifo_top + 1) % 32; \
void sound_timer_queue8(u32 channel, u8 value)
{
direct_sound_struct *ds = direct_sound_channel + channel;
sound_timer_queue(8, value);
}
void sound_timer_queue16(u32 channel, u16 value)
{
direct_sound_struct *ds = direct_sound_channel + channel;
sound_timer_queue(8, value & 0xFF);
sound_timer_queue(8, value >> 8);
}
void sound_timer_queue32(u32 channel, u32 value)
{
direct_sound_struct *ds = direct_sound_channel + channel;
sound_timer_queue(8, value & 0xFF);
sound_timer_queue(8, (value >> 8) & 0xFF);
sound_timer_queue(8, (value >> 16) & 0xFF);
sound_timer_queue(8, value >> 24);
}
// Unqueue 1 sample from the base of the DS FIFO and place it on the audio
// buffer for as many samples as necessary. If the DS FIFO is 16 bytes or
// smaller and if DMA is enabled for the sound channel initiate a DMA transfer
// to the DS FIFO.
#define render_sample_null() \
#define render_sample_left() \
sound_buffer[buffer_index] += current_sample + \
fp16_16_to_u32((next_sample - current_sample) * fifo_fractional) \
#define render_sample_right() \
sound_buffer[buffer_index + 1] += current_sample + \
fp16_16_to_u32((next_sample - current_sample) * fifo_fractional) \
#define render_sample_both() \
dest_sample = current_sample + \
fp16_16_to_u32((next_sample - current_sample) * fifo_fractional); \
sound_buffer[buffer_index] += dest_sample; \
sound_buffer[buffer_index + 1] += dest_sample \
#define render_samples(type) \
while(fifo_fractional <= 0xFFFF) \
{ \
render_sample_##type(); \
fifo_fractional += frequency_step; \
buffer_index = (buffer_index + 2) % BUFFER_SIZE; \
} \
void sound_timer(fixed16_16 frequency_step, u32 channel)
{
direct_sound_struct *ds = direct_sound_channel + channel;
fixed16_16 fifo_fractional = ds->fifo_fractional;
u32 buffer_index = ds->buffer_index;
s16 current_sample, next_sample, dest_sample;
current_sample = ds->fifo[ds->fifo_base] << 4;
ds->fifo_base = (ds->fifo_base + 1) % 32;
next_sample = ds->fifo[ds->fifo_base] << 4;
if(sound_on == 1)
{
if(ds->volume == DIRECT_SOUND_VOLUME_50)
{
current_sample >>= 1;
next_sample >>= 1;
}
switch(ds->status)
{
case DIRECT_SOUND_INACTIVE:
render_samples(null);
break;
case DIRECT_SOUND_RIGHT:
render_samples(right);
break;
case DIRECT_SOUND_LEFT:
render_samples(left);
break;
case DIRECT_SOUND_LEFTRIGHT:
render_samples(both);
break;
}
}
else
{
render_samples(null);
}
ds->buffer_index = buffer_index;
ds->fifo_fractional = fp16_16_fractional_part(fifo_fractional);
if(((ds->fifo_top - ds->fifo_base) % 32) <= 16)
{
if(dma[1].direct_sound_channel == channel)
dma_transfer(dma + 1);
if(dma[2].direct_sound_channel == channel)
dma_transfer(dma + 2);
}
}
void sound_reset_fifo(u32 channel)
{
direct_sound_struct *ds = direct_sound_channel;
memset(ds->fifo, 0, 32);
}
// Initial pattern data = 4bits (signed)
// Channel volume = 12bits
// Envelope volume = 14bits
// Master volume = 2bits
// Recalculate left and right volume as volume changes.
// To calculate the current sample, use (sample * volume) >> 16
// Square waves range from -8 (low) to 7 (high)
s8 square_pattern_duty[4][8] =
{
{ 0xF8, 0xF8, 0xF8, 0xF8, 0x07, 0xF8, 0xF8, 0xF8 },
{ 0xF8, 0xF8, 0xF8, 0xF8, 0x07, 0x07, 0xF8, 0xF8 },
{ 0xF8, 0xF8, 0x07, 0x07, 0x07, 0x07, 0xF8, 0xF8 },
{ 0x07, 0x07, 0x07, 0x07, 0xF8, 0xF8, 0x07, 0x07 },
};
s8 wave_samples[64];
u32 noise_table15[1024];
u32 noise_table7[4];
u32 gbc_sound_master_volume_table[4] = { 1, 2, 4, 0 };
u32 gbc_sound_channel_volume_table[8] =
{
fixed_div(0, 7, 12),
fixed_div(1, 7, 12),
fixed_div(2, 7, 12),
fixed_div(3, 7, 12),
fixed_div(4, 7, 12),
fixed_div(5, 7, 12),
fixed_div(6, 7, 12),
fixed_div(7, 7, 12)
};
u32 gbc_sound_envelope_volume_table[16] =
{
fixed_div(0, 15, 14),
fixed_div(1, 15, 14),
fixed_div(2, 15, 14),
fixed_div(3, 15, 14),
fixed_div(4, 15, 14),
fixed_div(5, 15, 14),
fixed_div(6, 15, 14),
fixed_div(7, 15, 14),
fixed_div(8, 15, 14),
fixed_div(9, 15, 14),
fixed_div(10, 15, 14),
fixed_div(11, 15, 14),
fixed_div(12, 15, 14),
fixed_div(13, 15, 14),
fixed_div(14, 15, 14),
fixed_div(15, 15, 14)
};
u32 gbc_sound_buffer_index = 0;
u32 gbc_sound_last_cpu_ticks = 0;
u32 gbc_sound_partial_ticks = 0;
u32 gbc_sound_master_volume_left;
u32 gbc_sound_master_volume_right;
u32 gbc_sound_master_volume;
#define update_volume_channel_envelope(channel) \
volume_##channel = gbc_sound_envelope_volume_table[envelope_volume] * \
gbc_sound_channel_volume_table[gbc_sound_master_volume_##channel] * \
gbc_sound_master_volume_table[gbc_sound_master_volume] \
#define update_volume_channel_noenvelope(channel) \
volume_##channel = gs->wave_volume * \
gbc_sound_channel_volume_table[gbc_sound_master_volume_##channel] * \
gbc_sound_master_volume_table[gbc_sound_master_volume] \
#define update_volume(type) \
update_volume_channel_##type(left); \
update_volume_channel_##type(right) \
#define update_tone_sweep() \
if(gs->sweep_status) \
{ \
u32 sweep_ticks = gs->sweep_ticks - 1; \
\
if(sweep_ticks == 0) \
{ \
u32 rate = gs->rate; \
\
if(gs->sweep_direction) \
rate = rate - (rate >> gs->sweep_shift); \
else \
rate = rate + (rate >> gs->sweep_shift); \
\
if(rate > 2048) \
rate = 2048; \
\
frequency_step = float_to_fp16_16(((131072.0 / (2048 - rate)) * 8.0) / \
sound_frequency); \
\
gs->frequency_step = frequency_step; \
gs->rate = rate; \
\
sweep_ticks = gs->sweep_initial_ticks; \
} \
gs->sweep_ticks = sweep_ticks; \
} \
#define update_tone_nosweep() \
#define update_tone_envelope() \
if(gs->envelope_status) \
{ \
u32 envelope_ticks = gs->envelope_ticks - 1; \
envelope_volume = gs->envelope_volume; \
\
if(envelope_ticks == 0) \
{ \
if(gs->envelope_direction) \
{ \
if(envelope_volume != 15) \
envelope_volume = gs->envelope_volume + 1; \
} \
else \
{ \
if(envelope_volume != 0) \
envelope_volume = gs->envelope_volume - 1; \
} \
\
update_volume(envelope); \
\
gs->envelope_volume = envelope_volume; \
gs->envelope_ticks = gs->envelope_initial_ticks; \
} \
else \
{ \
gs->envelope_ticks = envelope_ticks; \
} \
} \
#define update_tone_noenvelope() \
#define gbc_sound_synchronize() \
while(((gbc_sound_buffer_index - sound_buffer_base) % BUFFER_SIZE) > \
(audio_buffer_size * 2)) \
{ \
SDL_CondWait(sound_cv, sound_mutex); \
} \
#define update_tone_counters(envelope_op, sweep_op) \
tick_counter += gbc_sound_tick_step; \
if(tick_counter > 0xFFFF) \
{ \
if(gs->length_status) \
{ \
u32 length_ticks = gs->length_ticks - 1; \
gs->length_ticks = length_ticks; \
\
if(length_ticks == 0) \
{ \
gs->active_flag = 0; \
break; \
} \
} \
\
update_tone_##envelope_op(); \
update_tone_##sweep_op(); \
\
tick_counter &= 0xFFFF; \
} \
#define gbc_sound_render_sample_right() \
sound_buffer[buffer_index + 1] += (current_sample * volume_right) >> 22 \
#define gbc_sound_render_sample_left() \
sound_buffer[buffer_index] += (current_sample * volume_left) >> 22 \
#define gbc_sound_render_sample_both() \
gbc_sound_render_sample_right(); \
gbc_sound_render_sample_left() \
#define gbc_sound_render_samples(type, sample_length, envelope_op, sweep_op) \
for(i = 0; i < buffer_ticks; i++) \
{ \
current_sample = \
sample_data[fp16_16_to_u32(sample_index) % sample_length]; \
gbc_sound_render_sample_##type(); \
\
sample_index += frequency_step; \
buffer_index = (buffer_index + 2) % BUFFER_SIZE; \
\
update_tone_counters(envelope_op, sweep_op); \
} \
#define gbc_noise_wrap_full 32767
#define gbc_noise_wrap_half 126
#define get_noise_sample_full() \
current_sample = \
((s32)(noise_table15[fp16_16_to_u32(sample_index) >> 5] << \
(fp16_16_to_u32(sample_index) & 0x1F)) >> 31) & 0x0F \
#define get_noise_sample_half() \
current_sample = \
((s32)(noise_table7[fp16_16_to_u32(sample_index) >> 5] << \
(fp16_16_to_u32(sample_index) & 0x1F)) >> 31) & 0x0F \
#define gbc_sound_render_noise(type, noise_type, envelope_op, sweep_op) \
for(i = 0; i < buffer_ticks; i++) \
{ \
get_noise_sample_##noise_type(); \
gbc_sound_render_sample_##type(); \
\
sample_index += frequency_step; \
\
if(sample_index >= u32_to_fp16_16(gbc_noise_wrap_##noise_type)) \
sample_index -= u32_to_fp16_16(gbc_noise_wrap_##noise_type); \
\
buffer_index = (buffer_index + 2) % BUFFER_SIZE; \
update_tone_counters(envelope_op, sweep_op); \
} \
#define gbc_sound_render_channel(type, sample_length, envelope_op, sweep_op) \
buffer_index = gbc_sound_buffer_index; \
sample_index = gs->sample_index; \
frequency_step = gs->frequency_step; \
tick_counter = gs->tick_counter; \
\
update_volume(envelope_op); \
\
switch(gs->status) \
{ \
case GBC_SOUND_INACTIVE: \
break; \
\
case GBC_SOUND_LEFT: \
gbc_sound_render_##type(left, sample_length, envelope_op, sweep_op); \
break; \
\
case GBC_SOUND_RIGHT: \
gbc_sound_render_##type(right, sample_length, envelope_op, sweep_op); \
break; \
\
case GBC_SOUND_LEFTRIGHT: \
gbc_sound_render_##type(both, sample_length, envelope_op, sweep_op); \
break; \
} \
\
gs->sample_index = sample_index; \
gs->tick_counter = tick_counter; \
#define gbc_sound_load_wave_ram(bank) \
wave_bank = wave_samples + (bank * 32); \
for(i = 0, i2 = 0; i < 16; i++, i2 += 2) \
{ \
current_sample = wave_ram[i]; \
wave_bank[i2] = (((current_sample >> 4) & 0x0F) - 8); \
wave_bank[i2 + 1] = ((current_sample & 0x0F) - 8); \
} \
void synchronize_sound()
{
if (!global_enable_audio)
return;
SDL_LockMutex(sound_mutex);
gbc_sound_synchronize();
SDL_UnlockMutex(sound_mutex);
}
void update_gbc_sound(u32 cpu_ticks)
{
fixed16_16 buffer_ticks = float_to_fp16_16(((float)(cpu_ticks -
gbc_sound_last_cpu_ticks) * sound_frequency) / 16777216.0);
u32 i, i2;
gbc_sound_struct *gs = gbc_sound_channel;
fixed16_16 sample_index, frequency_step;
fixed16_16 tick_counter;
u32 buffer_index;
s32 volume_left, volume_right;
u32 envelope_volume;
s32 current_sample;
u32 sound_status = address16(io_registers, 0x84) & 0xFFF0;
s8 *sample_data;
s8 *wave_bank;
u8 *wave_ram = ((u8 *)io_registers) + 0x90;
if (!global_enable_audio)
return;
gbc_sound_partial_ticks += fp16_16_fractional_part(buffer_ticks);
buffer_ticks = fp16_16_to_u32(buffer_ticks);
if(gbc_sound_partial_ticks > 0xFFFF)
{
buffer_ticks += 1;
gbc_sound_partial_ticks &= 0xFFFF;
}
SDL_LockMutex(sound_mutex);
if(synchronize_flag && current_frameskip_type != auto_frameskip)
{
if(((gbc_sound_buffer_index - sound_buffer_base) % BUFFER_SIZE) >
(audio_buffer_size * 3 / 2))
{
while(((gbc_sound_buffer_index - sound_buffer_base) % BUFFER_SIZE) >
(audio_buffer_size * 3 / 2))
{
SDL_CondWait(sound_cv, sound_mutex);
}
#ifdef PSP_BUILD
if(current_frameskip_type == auto_frameskip)
{
sceDisplayWaitVblankStart();
real_frame_count = 0;
virtual_frame_count = 0;
}
#endif
/*
#ifdef GP2X_BUILD
if(current_frameskip_type == auto_frameskip)
{
u64 current_ticks;
u64 next_ticks;
get_ticks_us(¤t_ticks);
next_ticks = ((current_ticks + 16666) / 16667) * 16667;
delay_us(next_ticks - current_ticks);
get_ticks_us(&frame_count_initial_timestamp);
real_frame_count = 0;
virtual_frame_count = 0;
}
#endif
*/
}
}
if(sound_on == 1)
{
gs = gbc_sound_channel + 0;
if(gs->active_flag)
{
sound_status |= 0x01;
sample_data = gs->sample_data;
envelope_volume = gs->envelope_volume;
gbc_sound_render_channel(samples, 8, envelope, sweep);
}
gs = gbc_sound_channel + 1;
if(gs->active_flag)
{
sound_status |= 0x02;
sample_data = gs->sample_data;
envelope_volume = gs->envelope_volume;
gbc_sound_render_channel(samples, 8, envelope, nosweep);
}
gs = gbc_sound_channel + 2;
if(gbc_sound_wave_update)
{
if(gs->wave_bank == 1)
{
gbc_sound_load_wave_ram(1);
}
else
{
gbc_sound_load_wave_ram(0);
}
gbc_sound_wave_update = 0;
}
if((gs->active_flag) && (gs->master_enable))
{
sound_status |= 0x04;
sample_data = wave_samples;
if(gs->wave_type == 0)
{
if(gs->wave_bank == 1)
sample_data += 32;
gbc_sound_render_channel(samples, 32, noenvelope, nosweep);
}
else
{
gbc_sound_render_channel(samples, 64, noenvelope, nosweep);
}
}
gs = gbc_sound_channel + 3;
if(gs->active_flag)
{
sound_status |= 0x08;
envelope_volume = gs->envelope_volume;
if(gs->noise_type == 1)
{
gbc_sound_render_channel(noise, half, envelope, nosweep);
}
else
{
gbc_sound_render_channel(noise, full, envelope, nosweep);
}
}
}
address16(io_registers, 0x84) = sound_status;
SDL_CondSignal(sound_cv);
SDL_UnlockMutex(sound_mutex);
gbc_sound_last_cpu_ticks = cpu_ticks;
gbc_sound_buffer_index =
(gbc_sound_buffer_index + (buffer_ticks * 2)) % BUFFER_SIZE;
}
#define sound_copy_normal() \
current_sample = source[i] \
#define sound_copy(source_offset, length, render_type) \
_length = (length) / 2; \
source = (s16 *)(sound_buffer + source_offset); \
for(i = 0; i < _length; i++) \
{ \
sound_copy_##render_type(); \
if(current_sample > 2047) \
current_sample = 2047; \
if(current_sample < -2048) \
current_sample = -2048; \
\
stream_base[i] = current_sample << 4; \
source[i] = 0; \
} \
#define sound_copy_null(source_offset, length) \
_length = (length) / 2; \
source = (s16 *)(sound_buffer + source_offset); \
for(i = 0; i < _length; i++) \
{ \
stream_base[i] = 0; \
source[i] = 0; \
} \
void sound_callback(void *userdata, Uint8 *stream, int length)
{
u32 sample_length = length / 2;
u32 _length;
u32 i;
s16 *stream_base = (s16 *)stream;
s16 *source;
s32 current_sample;
SDL_LockMutex(sound_mutex);
while(((gbc_sound_buffer_index - sound_buffer_base) % BUFFER_SIZE) <
length)
{
SDL_CondWait(sound_cv, sound_mutex);
}
if(global_enable_audio)
{
if((sound_buffer_base + sample_length) >= BUFFER_SIZE)
{
u32 partial_length = (BUFFER_SIZE - sound_buffer_base) * 2;
sound_copy(sound_buffer_base, partial_length, normal);
source = (s16 *)sound_buffer;
sound_copy(0, length - partial_length, normal);
sound_buffer_base = (length - partial_length) / 2;
}
else
{
sound_copy(sound_buffer_base, length, normal);
sound_buffer_base += sample_length;
}
}
else
{
if((sound_buffer_base + sample_length) >= BUFFER_SIZE)
{
u32 partial_length = (BUFFER_SIZE - sound_buffer_base) * 2;
sound_copy_null(sound_buffer_base, partial_length);
source = (s16 *)sound_buffer;
sound_copy(0, length - partial_length, normal);
sound_buffer_base = (length - partial_length) / 2;
}
else
{
sound_copy_null(sound_buffer_base, length);
sound_buffer_base += sample_length;
}
}
SDL_CondSignal(sound_cv);
SDL_UnlockMutex(sound_mutex);
}
// Special thanks to blarrg for the LSFR frequency used in Meridian, as posted
// on the forum at http://meridian.overclocked.org:
// http://meridian.overclocked.org/cgi-bin/wwwthreads/showpost.pl?Board=merid
// angeneraldiscussion&Number=2069&page=0&view=expanded&mode=threaded&sb=4
// Hope you don't mind me borrowing it ^_-
void init_noise_table(u32 *table, u32 period, u32 bit_length)
{
u32 shift_register = 0xFF;
u32 mask = ~(1 << bit_length);
s32 table_pos, bit_pos;
u32 current_entry;
u32 table_period = (period + 31) / 32;
// Bits are stored in reverse order so they can be more easily moved to
// bit 31, for sign extended shift down.
for(table_pos = 0; table_pos < table_period; table_pos++)
{
current_entry = 0;
for(bit_pos = 31; bit_pos >= 0; bit_pos--)
{
current_entry |= (shift_register & 0x01) << bit_pos;
shift_register =
((1 & (shift_register ^ (shift_register >> 1))) << bit_length) |
((shift_register >> 1) & mask);
}
table[table_pos] = current_entry;
}
}
void reset_sound()
{
direct_sound_struct *ds = direct_sound_channel;
gbc_sound_struct *gs = gbc_sound_channel;
u32 i;
if (!global_enable_audio)
return;
sound_on = 0;
sound_buffer_base = 0;
sound_last_cpu_ticks = 0;
memset(sound_buffer, 0, sizeof(sound_buffer));
for(i = 0; i < 2; i++, ds++)
{
ds->buffer_index = 0;
ds->status = DIRECT_SOUND_INACTIVE;
ds->fifo_top = 0;
ds->fifo_base = 0;
ds->fifo_fractional = 0;
ds->last_cpu_ticks = 0;
memset(ds->fifo, 0, 32);
}
gbc_sound_buffer_index = 0;
gbc_sound_last_cpu_ticks = 0;
gbc_sound_partial_ticks = 0;
gbc_sound_master_volume_left = 0;
gbc_sound_master_volume_right = 0;
gbc_sound_master_volume = 0;
memset(wave_samples, 0, 64);
for(i = 0; i < 4; i++, gs++)
{
gs->status = GBC_SOUND_INACTIVE;
gs->sample_data = square_pattern_duty[2];
gs->active_flag = 0;
}
}
void sound_exit()
{
if (!global_enable_audio)
return;
gbc_sound_buffer_index =
(sound_buffer_base + audio_buffer_size) % BUFFER_SIZE;
SDL_PauseAudio(1);
SDL_CondSignal(sound_cv);
}
void init_sound()
{
#ifdef PSP_BUILD
audio_buffer_size = (audio_buffer_size_number * 1024) + 3072;
#else
audio_buffer_size = 16 << audio_buffer_size_number;
#endif
audio_buffer_size = 2048 << audio_buffer_size_number;
SDL_AudioSpec desired_spec =
{
sound_frequency,
AUDIO_S16,
2,
0,
audio_buffer_size / 4,
0,
0,
sound_callback,
NULL
};
if (!global_enable_audio)
return;
gbc_sound_tick_step =
float_to_fp16_16(256.0 / sound_frequency);
init_noise_table(noise_table15, 32767, 14);
init_noise_table(noise_table7, 127, 6);
reset_sound();
SDL_OpenAudio(&desired_spec, &sound_settings);
sound_frequency = sound_settings.freq;
sound_mutex = SDL_CreateMutex();
sound_cv = SDL_CreateCond();
SDL_PauseAudio(0);
}
#define sound_savestate_builder(type) \
void sound_##type##_savestate(file_tag_type savestate_file) \
{ \
file_##type##_variable(savestate_file, sound_on); \
file_##type##_variable(savestate_file, sound_buffer_base); \
file_##type##_variable(savestate_file, sound_last_cpu_ticks); \
file_##type##_variable(savestate_file, gbc_sound_buffer_index); \
file_##type##_variable(savestate_file, gbc_sound_last_cpu_ticks); \
file_##type##_variable(savestate_file, gbc_sound_partial_ticks); \
file_##type##_variable(savestate_file, gbc_sound_master_volume_left); \
file_##type##_variable(savestate_file, gbc_sound_master_volume_right); \
file_##type##_variable(savestate_file, gbc_sound_master_volume); \
file_##type##_array(savestate_file, wave_samples); \
file_##type##_array(savestate_file, direct_sound_channel); \
file_##type##_array(savestate_file, gbc_sound_channel); \
} \
sound_savestate_builder(read);
sound_savestate_builder(write_mem);