aboutsummaryrefslogtreecommitdiff
path: root/audio/miles_adlib.cpp
blob: 0693d1e7ac4eb75a09604c90506dd86d33586709 (plain)
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
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * 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 "audio/miles.h"

#include "common/file.h"
#include "common/system.h"
#include "common/textconsole.h"

#include "audio/fmopl.h"

namespace Audio {

// Miles Audio AdLib/OPL3 driver
//
// TODO: currently missing: OPL3 4-op voices
//
// Special cases (great for testing):
// - sustain feature is used by Return To Zork (demo) right at the start
// - sherlock holmes 2 does lots of priority sorts right at the start of the intro

#define MILES_ADLIB_VIRTUAL_FMVOICES_COUNT_MAX 20
#define MILES_ADLIB_PHYSICAL_FMVOICES_COUNT_MAX 18

#define MILES_ADLIB_PERCUSSION_BANK 127

#define MILES_ADLIB_STEREO_PANNING_THRESHOLD_LEFT 27
#define MILES_ADLIB_STEREO_PANNING_THRESHOLD_RIGHT 100

enum kMilesAdLibUpdateFlags {
	kMilesAdLibUpdateFlags_None    = 0,
	kMilesAdLibUpdateFlags_Reg_20  = 1 << 0,
	kMilesAdLibUpdateFlags_Reg_40  = 1 << 1,
	kMilesAdLibUpdateFlags_Reg_60  = 1 << 2, // register 0x6x + 0x8x
	kMilesAdLibUpdateFlags_Reg_C0  = 1 << 3,
	kMilesAdLibUpdateFlags_Reg_E0  = 1 << 4,
	kMilesAdLibUpdateFlags_Reg_A0  = 1 << 5, // register 0xAx + 0xBx
	kMilesAdLibUpdateFlags_Reg_All = 0x3F
};

uint16 milesAdLibOperator1Register[MILES_ADLIB_PHYSICAL_FMVOICES_COUNT_MAX] = {
	0x0000, 0x0001, 0x0002, 0x0008, 0x0009, 0x000A, 0x0010, 0x0011, 0x0012,
	0x0100, 0x0101, 0x0102, 0x0108, 0x0109, 0x010A, 0x0110, 0x0111, 0x0112
};

uint16 milesAdLibOperator2Register[MILES_ADLIB_PHYSICAL_FMVOICES_COUNT_MAX] = {
	0x0003, 0x0004, 0x0005, 0x000B, 0x000C, 0x000D, 0x0013, 0x0014, 0x0015,
	0x0103, 0x0104, 0x0105, 0x010B, 0x010C, 0x010D, 0x0113, 0x0114, 0x0115
};

uint16 milesAdLibChannelRegister[MILES_ADLIB_PHYSICAL_FMVOICES_COUNT_MAX] = {
	0x0000, 0x0001, 0x0002, 0x0003, 0x0004, 0x0005, 0x0006, 0x0007, 0x0008,
	0x0100, 0x0101, 0x0102, 0x0103, 0x0104, 0x0105, 0x0106, 0x0107, 0x0108
};

struct InstrumentEntry {
	byte bankId;
	byte patchId;
	int16 transposition;
	byte reg20op1;
	byte reg40op1;
	byte reg60op1;
	byte reg80op1;
	byte regE0op1;
	byte reg20op2;
	byte reg40op2;
	byte reg60op2;
	byte reg80op2;
	byte regE0op2;
	byte regC0;
};

// hardcoded, dumped from ADLIB.MDI
uint16 milesAdLibFrequencyLookUpTable[] = {
	0x02B2, 0x02B4, 0x02B7, 0x02B9, 0x02BC, 0x02BE, 0x02C1, 0x02C3, 0x02C6, 0x02C9, 0x02CB, 0x02CE,
	0x02D0, 0x02D3, 0x02D6, 0x02D8, 0x02DB, 0x02DD, 0x02E0, 0x02E3, 0x02E5, 0x02E8, 0x02EB, 0x02ED,
	0x02F0, 0x02F3, 0x02F6, 0x02F8, 0x02FB, 0x02FE, 0x0301, 0x0303, 0x0306, 0x0309, 0x030C, 0x030F,
	0x0311, 0x0314, 0x0317, 0x031A, 0x031D, 0x0320, 0x0323, 0x0326, 0x0329, 0x032B, 0x032E, 0x0331,
	0x0334, 0x0337, 0x033A, 0x033D, 0x0340, 0x0343, 0x0346, 0x0349, 0x034C, 0x034F, 0x0352, 0x0356,
	0x0359, 0x035C, 0x035F, 0x0362, 0x0365, 0x0368, 0x036B, 0x036F, 0x0372, 0x0375, 0x0378, 0x037B,
	0x037F, 0x0382, 0x0385, 0x0388, 0x038C, 0x038F, 0x0392, 0x0395, 0x0399, 0x039C, 0x039F, 0x03A3,
	0x03A6, 0x03A9, 0x03AD, 0x03B0, 0x03B4, 0x03B7, 0x03BB, 0x03BE, 0x03C1, 0x03C5, 0x03C8, 0x03CC,
	0x03CF, 0x03D3, 0x03D7, 0x03DA, 0x03DE, 0x03E1, 0x03E5, 0x03E8, 0x03EC, 0x03F0, 0x03F3, 0x03F7,
	0x03FB, 0x03FE, 0xFE01, 0xFE03, 0xFE05, 0xFE07, 0xFE08, 0xFE0A, 0xFE0C, 0xFE0E, 0xFE10, 0xFE12,
	0xFE14, 0xFE16, 0xFE18, 0xFE1A, 0xFE1C, 0xFE1E, 0xFE20, 0xFE21, 0xFE23, 0xFE25, 0xFE27, 0xFE29,
	0xFE2B, 0xFE2D, 0xFE2F, 0xFE31, 0xFE34, 0xFE36, 0xFE38, 0xFE3A, 0xFE3C, 0xFE3E, 0xFE40, 0xFE42,
	0xFE44, 0xFE46, 0xFE48, 0xFE4A, 0xFE4C, 0xFE4F, 0xFE51, 0xFE53, 0xFE55, 0xFE57, 0xFE59, 0xFE5C,
	0xFE5E, 0xFE60, 0xFE62, 0xFE64, 0xFE67, 0xFE69, 0xFE6B, 0xFE6D, 0xFE6F, 0xFE72, 0xFE74, 0xFE76,
	0xFE79, 0xFE7B, 0xFE7D, 0xFE7F, 0xFE82, 0xFE84, 0xFE86, 0xFE89, 0xFE8B, 0xFE8D, 0xFE90, 0xFE92,
	0xFE95, 0xFE97, 0xFE99, 0xFE9C, 0xFE9E, 0xFEA1, 0xFEA3, 0xFEA5, 0xFEA8, 0xFEAA, 0xFEAD, 0xFEAF
};

// hardcoded, dumped from ADLIB.MDI
uint16 milesAdLibVolumeSensitivityTable[] = {
	82, 85, 88, 91, 94, 97, 100, 103, 106, 109, 112, 115, 118, 121, 124, 127
};


class MidiDriver_Miles_AdLib : public MidiDriver {
public:
	MidiDriver_Miles_AdLib(InstrumentEntry *instrumentTablePtr, uint16 instrumentTableCount);
	virtual ~MidiDriver_Miles_AdLib();

	// MidiDriver
	int open();
	void close();
	void send(uint32 b);
	MidiChannel *allocateChannel() { return NULL; }
	MidiChannel *getPercussionChannel() { return NULL; }

	bool isOpen() const { return _isOpen; }
	uint32 getBaseTempo() { return 1000000 / OPL::OPL::kDefaultCallbackFrequency; }

	void setVolume(byte volume);
	virtual uint32 property(int prop, uint32 param);

	void setTimerCallback(void *timerParam, Common::TimerManager::TimerProc timerProc);

private:
	bool _modeOPL3;
	byte _modePhysicalFmVoicesCount;
	byte _modeVirtualFmVoicesCount;
	bool _modeStereo;

	// Structure to hold information about current status of MIDI Channels
	struct MidiChannelEntry {
		byte   currentPatchBank;
		const  InstrumentEntry *currentInstrumentPtr;
		uint16 currentPitchBender;
		byte   currentPitchRange;
		byte   currentVoiceProtection;

		byte   currentVolume;
		byte   currentVolumeExpression;

		byte   currentPanning;

		byte   currentModulation;
		byte   currentSustain;

		byte   currentActiveVoicesCount;

		MidiChannelEntry() : currentPatchBank(0),
							currentInstrumentPtr(NULL),
							currentPitchBender(MILES_PITCHBENDER_DEFAULT),
							currentPitchRange(0),
							currentVoiceProtection(0),
							currentVolume(0), currentVolumeExpression(0),
							currentPanning(0),
							currentModulation(0),
							currentSustain(0),
							currentActiveVoicesCount(0) { }
	};

	// Structure to hold information about current status of virtual FM Voices
	struct VirtualFmVoiceEntry {
		bool   inUse;
		byte   actualMidiChannel;

		const  InstrumentEntry *currentInstrumentPtr;

		bool   isPhysical;
		byte   physicalFmVoice;

		uint16 currentPriority;

		byte   currentOriginalMidiNote;
		byte   currentNote;
		int16  currentTransposition;
		byte   currentVelocity;

		bool   sustained;

		VirtualFmVoiceEntry(): inUse(false),
								actualMidiChannel(0),
								currentInstrumentPtr(NULL),
								isPhysical(false), physicalFmVoice(0),
								currentPriority(0),
								currentOriginalMidiNote(0),
								currentNote(0),
								currentTransposition(0),
								currentVelocity(0),
								sustained(false) { }
	};

	// Structure to hold information about current status of physical FM Voices
	struct PhysicalFmVoiceEntry {
		bool   inUse;
		byte   virtualFmVoice;

		byte   currentB0hReg;

		PhysicalFmVoiceEntry(): inUse(false),
								virtualFmVoice(0),
								currentB0hReg(0) { }
	};

	OPL::OPL *_opl;
	int _masterVolume;

	Common::TimerManager::TimerProc _adlibTimerProc;
	void *_adlibTimerParam;

	bool _isOpen;

	// stores information about all MIDI channels (not the actual OPL FM voice channels!)
	MidiChannelEntry _midiChannels[MILES_MIDI_CHANNEL_COUNT];

	// stores information about all virtual OPL FM voices
	VirtualFmVoiceEntry _virtualFmVoices[MILES_ADLIB_VIRTUAL_FMVOICES_COUNT_MAX];

	// stores information about all physical OPL FM voices
	PhysicalFmVoiceEntry _physicalFmVoices[MILES_ADLIB_PHYSICAL_FMVOICES_COUNT_MAX];

	// holds all instruments
	InstrumentEntry *_instrumentTablePtr;
	uint16           _instrumentTableCount;

	bool circularPhysicalAssignment;
	byte circularPhysicalAssignmentFmVoice;

	void onTimer();

	void resetData();
	void resetAdLib();
	void resetAdLibOperatorRegisters(byte baseRegister, byte value);
	void resetAdLibFMVoiceChannelRegisters(byte baseRegister, byte value);

	void setRegister(int reg, int value);

	int16 searchFreeVirtualFmVoiceChannel();
	int16 searchFreePhysicalFmVoiceChannel();

	void noteOn(byte midiChannel, byte note, byte velocity);
	void noteOff(byte midiChannel, byte note);

	void prioritySort();

	void releaseFmVoice(byte virtualFmVoice);

	void releaseSustain(byte midiChannel);

	void updatePhysicalFmVoice(byte virtualFmVoice, bool keyOn, uint16 registerUpdateFlags);

	void controlChange(byte midiChannel, byte controllerNumber, byte controllerValue);
	void programChange(byte midiChannel, byte patchId);

	const InstrumentEntry *searchInstrument(byte bankId, byte patchId);

	void pitchBendChange(byte MIDIchannel, byte parameter1, byte parameter2);
};

MidiDriver_Miles_AdLib::MidiDriver_Miles_AdLib(InstrumentEntry *instrumentTablePtr, uint16 instrumentTableCount)
	: _masterVolume(15), _opl(0),
	  _adlibTimerProc(0), _adlibTimerParam(0), _isOpen(false) {

	_instrumentTablePtr = instrumentTablePtr;
	_instrumentTableCount = instrumentTableCount;

	// Set up for OPL3, we will downgrade in case we can't create OPL3 emulator
	// regular AdLib (OPL2) card
	_modeOPL3 = true;
	_modeVirtualFmVoicesCount = 20;
	_modePhysicalFmVoicesCount = 18;
	_modeStereo = true;

	// Older Miles Audio drivers did not do a circular assign for physical FM-voices
	// Sherlock Holmes 2 used the circular assign
	circularPhysicalAssignment = true;
	// this way the first circular physical FM-voice search will start at FM-voice 0
	circularPhysicalAssignmentFmVoice = MILES_ADLIB_PHYSICAL_FMVOICES_COUNT_MAX;

	resetData();
}

MidiDriver_Miles_AdLib::~MidiDriver_Miles_AdLib() {
	delete[] _instrumentTablePtr; // is created in factory MidiDriver_Miles_AdLib_create()
}

int MidiDriver_Miles_AdLib::open() {
	if (_modeOPL3) {
		// Try to create OPL3 first
		_opl = OPL::Config::create(OPL::Config::kOpl3);
	}
	if (!_opl) {
		// not created yet, downgrade to OPL2
		_modeOPL3 = false;
		_modeVirtualFmVoicesCount = 16;
		_modePhysicalFmVoicesCount = 9;
		_modeStereo = false;

		_opl = OPL::Config::create(OPL::Config::kOpl2);
	}

	if (!_opl) {
		// We still got nothing -> can't do anything anymore
		return -1;
	}

	_opl->init();

	_isOpen = true;

	_opl->start(new Common::Functor0Mem<void, MidiDriver_Miles_AdLib>(this, &MidiDriver_Miles_AdLib::onTimer));

	resetAdLib();

	return 0;
}

void MidiDriver_Miles_AdLib::close() {
	delete _opl;
	_isOpen = false;
}

void MidiDriver_Miles_AdLib::setVolume(byte volume) {
	_masterVolume = volume;
	//renewNotes(-1, true);
}

void MidiDriver_Miles_AdLib::onTimer() {
	if (_adlibTimerProc)
		(*_adlibTimerProc)(_adlibTimerParam);
}

void MidiDriver_Miles_AdLib::resetData() {
	memset(_midiChannels, 0, sizeof(_midiChannels));
	memset(_virtualFmVoices, 0, sizeof(_virtualFmVoices));
	memset(_physicalFmVoices, 0, sizeof(_physicalFmVoices));

	for (byte midiChannel = 0; midiChannel < MILES_MIDI_CHANNEL_COUNT; midiChannel++) {
		// defaults, were sent to driver during driver initialization
		_midiChannels[midiChannel].currentVolume = 0x7F;
		_midiChannels[midiChannel].currentPanning = 0x40; // center
		_midiChannels[midiChannel].currentVolumeExpression = 127;

		// Miles Audio 2: hardcoded pitch range as a global (not channel specific), set to 12
		// Miles Audio 3: pitch range per MIDI channel
		_midiChannels[midiChannel].currentPitchBender = MILES_PITCHBENDER_DEFAULT;
		_midiChannels[midiChannel].currentPitchRange = 12;
	}

}

void MidiDriver_Miles_AdLib::resetAdLib() {
	if (_modeOPL3) {
		setRegister(0x105, 1); // enable OPL3
		setRegister(0x104, 0); // activate 18 2-operator FM-voices
	}

	setRegister(0x01, 0x20); // enable waveform control on both operators
	setRegister(0x04, 0xE0); // Timer control

	setRegister(0x08, 0); // select FM music mode
	setRegister(0xBD, 0); // disable Rhythm

	// reset FM voice instrument data
	resetAdLibOperatorRegisters(0x20, 0);
	resetAdLibOperatorRegisters(0x60, 0);
	resetAdLibOperatorRegisters(0x80, 0);
	resetAdLibFMVoiceChannelRegisters(0xA0, 0);
	resetAdLibFMVoiceChannelRegisters(0xB0, 0);
	resetAdLibFMVoiceChannelRegisters(0xC0, 0);
	resetAdLibOperatorRegisters(0xE0, 0);
	resetAdLibOperatorRegisters(0x40, 0x3F);
}

void MidiDriver_Miles_AdLib::resetAdLibOperatorRegisters(byte baseRegister, byte value) {
	byte physicalFmVoice = 0;

	for (physicalFmVoice = 0; physicalFmVoice < _modePhysicalFmVoicesCount; physicalFmVoice++) {
		setRegister(baseRegister + milesAdLibOperator1Register[physicalFmVoice], value);
		setRegister(baseRegister + milesAdLibOperator2Register[physicalFmVoice], value);
	}
}

void MidiDriver_Miles_AdLib::resetAdLibFMVoiceChannelRegisters(byte baseRegister, byte value) {
	byte physicalFmVoice = 0;

	for (physicalFmVoice = 0; physicalFmVoice < _modePhysicalFmVoicesCount; physicalFmVoice++) {
		setRegister(baseRegister + milesAdLibChannelRegister[physicalFmVoice], value);
	}
}

// MIDI messages can be found at http://www.midi.org/techspecs/midimessages.php
void MidiDriver_Miles_AdLib::send(uint32 b) {
	byte command = b & 0xf0;
	byte channel = b & 0xf;
	byte op1 = (b >> 8) & 0xff;
	byte op2 = (b >> 16) & 0xff;

	switch (command) {
	case 0x80:
		noteOff(channel, op1);
		break;
	case 0x90:
		noteOn(channel, op1, op2);
		break;
	case 0xb0: // Control change
		controlChange(channel, op1, op2);
		break;
	case 0xc0: // Program Change
		programChange(channel, op1);
		break;
	case 0xa0: // Polyphonic key pressure (aftertouch)
	case 0xd0: // Channel pressure (aftertouch)
		// Aftertouch doesn't seem to be implemented in the Miles Audio AdLib driver
		break;
	case 0xe0:
		pitchBendChange(channel, op1, op2);
		break;
	case 0xf0: // SysEx
		warning("MILES-ADLIB: SysEx: %x", b);
		break;
	default:
		warning("MILES-ADLIB: Unknown event %02x", command);
	}
}

void MidiDriver_Miles_AdLib::setTimerCallback(void *timerParam, Common::TimerManager::TimerProc timerProc) {
	_adlibTimerProc = timerProc;
	_adlibTimerParam = timerParam;
}

int16 MidiDriver_Miles_AdLib::searchFreeVirtualFmVoiceChannel() {
	for (byte virtualFmVoice = 0; virtualFmVoice < _modeVirtualFmVoicesCount; virtualFmVoice++) {
		if (!_virtualFmVoices[virtualFmVoice].inUse)
			return virtualFmVoice;
	}
	return -1;
}

int16 MidiDriver_Miles_AdLib::searchFreePhysicalFmVoiceChannel() {
	if (!circularPhysicalAssignment) {
		// Older assign logic
		for (byte physicalFmVoice = 0; physicalFmVoice < _modePhysicalFmVoicesCount; physicalFmVoice++) {
			if (!_physicalFmVoices[physicalFmVoice].inUse)
				return physicalFmVoice;
		}
	} else {
		// Newer one
		// Remembers last physical FM-voice and searches from that spot
		byte physicalFmVoice = circularPhysicalAssignmentFmVoice;
		for (byte physicalFmVoiceCount = 0; physicalFmVoiceCount < _modePhysicalFmVoicesCount; physicalFmVoiceCount++) {
			physicalFmVoice++;
			if (physicalFmVoice >= _modePhysicalFmVoicesCount)
				physicalFmVoice = 0;
			if (!_physicalFmVoices[physicalFmVoice].inUse) {
				circularPhysicalAssignmentFmVoice = physicalFmVoice;
				return physicalFmVoice;
			}
		}
	}
	return -1;
}

void MidiDriver_Miles_AdLib::noteOn(byte midiChannel, byte note, byte velocity) {
	const InstrumentEntry *instrumentPtr = NULL;

	if (velocity == 0) {
		noteOff(midiChannel, note);
		return;
	}

	if (midiChannel == 9) {
		// percussion channel
		// search for instrument according to given note
		instrumentPtr = searchInstrument(MILES_ADLIB_PERCUSSION_BANK, note);
	} else {
		// directly get instrument of channel
		instrumentPtr = _midiChannels[midiChannel].currentInstrumentPtr;
	}
	if (!instrumentPtr) {
		warning("MILES-ADLIB: noteOn: invalid instrument");
		return;
	}

	//warning("Note On: channel %d, note %d, velocity %d, instrument %d/%d", midiChannel, note, velocity, instrumentPtr->bankId, instrumentPtr->patchId);

	// look for free virtual FM voice
	int16 virtualFmVoice = searchFreeVirtualFmVoiceChannel();

	if (virtualFmVoice == -1) {
		// Out of virtual voices,  can't do anything about it
		return;
	}

	// Scale back velocity
	velocity = (velocity & 0x7F) >> 3;
	velocity = milesAdLibVolumeSensitivityTable[velocity];

	if (midiChannel != 9) {
		_virtualFmVoices[virtualFmVoice].currentNote = note;
		_virtualFmVoices[virtualFmVoice].currentTransposition = instrumentPtr->transposition;
	} else {
		// Percussion channel
		_virtualFmVoices[virtualFmVoice].currentNote = instrumentPtr->transposition;
		_virtualFmVoices[virtualFmVoice].currentTransposition = 0;
	}

	_virtualFmVoices[virtualFmVoice].inUse = true;
	_virtualFmVoices[virtualFmVoice].actualMidiChannel = midiChannel;
	_virtualFmVoices[virtualFmVoice].currentOriginalMidiNote = note;
	_virtualFmVoices[virtualFmVoice].currentInstrumentPtr = instrumentPtr;
	_virtualFmVoices[virtualFmVoice].currentVelocity = velocity;
	_virtualFmVoices[virtualFmVoice].isPhysical = false;
	_virtualFmVoices[virtualFmVoice].sustained = false;
	_virtualFmVoices[virtualFmVoice].currentPriority = 32767;

	int16 physicalFmVoice = searchFreePhysicalFmVoiceChannel();
	if (physicalFmVoice == -1) {
		// None found
		// go through priorities and reshuffle voices
		prioritySort();
		return;
	}

	// Another voice active on this MIDI channel
	_midiChannels[midiChannel].currentActiveVoicesCount++;

	// Mark virtual FM-Voice as being connected to physical FM-Voice
	_virtualFmVoices[virtualFmVoice].isPhysical = true;
	_virtualFmVoices[virtualFmVoice].physicalFmVoice = physicalFmVoice;

	// Mark physical FM-Voice as being connected to virtual FM-Voice
	_physicalFmVoices[physicalFmVoice].inUse = true;
	_physicalFmVoices[physicalFmVoice].virtualFmVoice = virtualFmVoice;

	// Update the physical FM-Voice
	updatePhysicalFmVoice(virtualFmVoice, true, kMilesAdLibUpdateFlags_Reg_All);
}

void MidiDriver_Miles_AdLib::noteOff(byte midiChannel, byte note) {
	//warning("Note Off: channel %d, note %d", midiChannel, note);

	// Search through all virtual FM-Voices for current midiChannel + note
	for (byte virtualFmVoice = 0; virtualFmVoice < _modeVirtualFmVoicesCount; virtualFmVoice++) {
		if (_virtualFmVoices[virtualFmVoice].inUse) {
			if ((_virtualFmVoices[virtualFmVoice].actualMidiChannel == midiChannel) && (_virtualFmVoices[virtualFmVoice].currentOriginalMidiNote == note)) {
				// found one
				if (_midiChannels[midiChannel].currentSustain >= 64) {
					_virtualFmVoices[virtualFmVoice].sustained = true;
					continue;
				}
				// 
				releaseFmVoice(virtualFmVoice);
			}
		}
	}
}

void MidiDriver_Miles_AdLib::prioritySort() {
	byte   virtualFmVoice = 0;
	uint16 virtualPriority = 0;
	uint16 virtualPriorities[MILES_ADLIB_VIRTUAL_FMVOICES_COUNT_MAX];
	uint16 virtualFmVoicesCount = 0;
	byte   midiChannel = 0;

	memset(&virtualPriorities, 0, sizeof(virtualPriorities));

	//warning("prioritysort");

	// First calculate priorities for all virtual FM voices, that are in use
	for (virtualFmVoice = 0; virtualFmVoice < _modeVirtualFmVoicesCount; virtualFmVoice++) {
		if (_virtualFmVoices[virtualFmVoice].inUse) {
			virtualFmVoicesCount++;

			midiChannel = _virtualFmVoices[virtualFmVoice].actualMidiChannel;
			if (_midiChannels[midiChannel].currentVoiceProtection >= 64) {
				// Voice protection enabled
				virtualPriority = 0xFFFF;
			} else {
				virtualPriority = _virtualFmVoices[virtualFmVoice].currentPriority;
			}
			byte currentActiveVoicesCount = _midiChannels[midiChannel].currentActiveVoicesCount;
			if (virtualPriority >= currentActiveVoicesCount) {
				virtualPriority -= _midiChannels[midiChannel].currentActiveVoicesCount;
			} else {
				virtualPriority = 0; // overflow, should never happen
			}
			virtualPriorities[virtualFmVoice] = virtualPriority;
		}
	}

	// 	
	while (virtualFmVoicesCount) {
		uint16 unvoicedHighestPriority = 0;
		byte   unvoicedHighestFmVoice = 0;
		uint16 voicedLowestPriority = 65535;
		byte   voicedLowestFmVoice = 0;

		for (virtualFmVoice = 0; virtualFmVoice < _modeVirtualFmVoicesCount; virtualFmVoice++) {
			if (_virtualFmVoices[virtualFmVoice].inUse) {
				virtualPriority = virtualPriorities[virtualFmVoice];
				if (!_virtualFmVoices[virtualFmVoice].isPhysical) {
					// currently not physical, so unvoiced
					if (virtualPriority >= unvoicedHighestPriority) {
						unvoicedHighestPriority = virtualPriority;
						unvoicedHighestFmVoice  = virtualFmVoice;
					}
				} else {
					// currently physical, so voiced
					if (virtualPriority <= voicedLowestPriority) {
						voicedLowestPriority = virtualPriority;
						voicedLowestFmVoice  = virtualFmVoice;
					}
				}
			}
		}

		if (unvoicedHighestPriority < voicedLowestPriority)
			break; // We are done

		if (unvoicedHighestPriority == 0)
			break;

		// Safety checks
		assert(_virtualFmVoices[voicedLowestFmVoice].isPhysical);
		assert(!_virtualFmVoices[unvoicedHighestFmVoice].isPhysical);

		// Steal this physical voice
		byte physicalFmVoice = _virtualFmVoices[voicedLowestFmVoice].physicalFmVoice;

		//warning("MILES-ADLIB: stealing physical FM-Voice %d from virtual FM-Voice %d for virtual FM-Voice %d", physicalFmVoice, voicedLowestFmVoice, unvoicedHighestFmVoice);
		//warning("priority old %d, priority new %d", unvoicedHighestPriority, voicedLowestPriority);

		releaseFmVoice(voicedLowestFmVoice);

		// Get some data of the unvoiced highest priority virtual FM Voice
		midiChannel = _virtualFmVoices[unvoicedHighestFmVoice].actualMidiChannel;

		// Another voice active on this MIDI channel
		_midiChannels[midiChannel].currentActiveVoicesCount++;

		// Mark virtual FM-Voice as being connected to physical FM-Voice
		_virtualFmVoices[unvoicedHighestFmVoice].isPhysical = true;
		_virtualFmVoices[unvoicedHighestFmVoice].physicalFmVoice = physicalFmVoice;

		// Mark physical FM-Voice as being connected to virtual FM-Voice
		_physicalFmVoices[physicalFmVoice].inUse = true;
		_physicalFmVoices[physicalFmVoice].virtualFmVoice = unvoicedHighestFmVoice;

		// Update the physical FM-Voice
		updatePhysicalFmVoice(unvoicedHighestFmVoice, true, kMilesAdLibUpdateFlags_Reg_All);

		virtualFmVoicesCount--;
	}
}

void MidiDriver_Miles_AdLib::releaseFmVoice(byte virtualFmVoice) {
	// virtual Voice not actually played? -> exit
	if (!_virtualFmVoices[virtualFmVoice].isPhysical) {
		_virtualFmVoices[virtualFmVoice].inUse = false;
		return;
	}

	byte midiChannel = _virtualFmVoices[virtualFmVoice].actualMidiChannel;
	byte physicalFmVoice = _virtualFmVoices[virtualFmVoice].physicalFmVoice;

	// stop note from playing
	updatePhysicalFmVoice(virtualFmVoice, false, kMilesAdLibUpdateFlags_Reg_A0);

	// this virtual FM voice isn't physical anymore
	_virtualFmVoices[virtualFmVoice].isPhysical = false;
	_virtualFmVoices[virtualFmVoice].inUse = false;

	// Remove physical FM-Voice from being active
	_physicalFmVoices[physicalFmVoice].inUse = false;

	// One less voice active on this MIDI channel
	assert(_midiChannels[midiChannel].currentActiveVoicesCount);
	_midiChannels[midiChannel].currentActiveVoicesCount--;	
}

void MidiDriver_Miles_AdLib::releaseSustain(byte midiChannel) {
	// Search through all virtual FM-Voices for currently sustained notes and call noteOff on them
	for (byte virtualFmVoice = 0; virtualFmVoice < _modeVirtualFmVoicesCount; virtualFmVoice++) {
		if (_virtualFmVoices[virtualFmVoice].inUse) {
			if ((_virtualFmVoices[virtualFmVoice].actualMidiChannel == midiChannel) && (_virtualFmVoices[virtualFmVoice].sustained)) {
				// is currently sustained
				// so do a noteOff (which will check current sustain controller)
				noteOff(midiChannel, _virtualFmVoices[virtualFmVoice].currentOriginalMidiNote);
			}
		}
	}
}

void MidiDriver_Miles_AdLib::updatePhysicalFmVoice(byte virtualFmVoice, bool keyOn, uint16 registerUpdateFlags) {
	byte midiChannel = _virtualFmVoices[virtualFmVoice].actualMidiChannel;

	if (!_virtualFmVoices[virtualFmVoice].isPhysical) {
		// virtual FM-Voice has no physical FM-Voice assigned? -> ignore
		return;
	}

	byte                   physicalFmVoice = _virtualFmVoices[virtualFmVoice].physicalFmVoice;
	const InstrumentEntry *instrumentPtr = _virtualFmVoices[virtualFmVoice].currentInstrumentPtr;

	uint16 op1Reg = milesAdLibOperator1Register[physicalFmVoice];
	uint16 op2Reg = milesAdLibOperator2Register[physicalFmVoice];
	uint16 channelReg = milesAdLibChannelRegister[physicalFmVoice];

	uint16 compositeVolume = 0;

	if (registerUpdateFlags & kMilesAdLibUpdateFlags_Reg_40) {
		// Calculate new volume
		byte midiVolume = _midiChannels[midiChannel].currentVolume;
		byte midiVolumeExpression = _midiChannels[midiChannel].currentVolumeExpression;
		compositeVolume = midiVolume * midiVolumeExpression * 2;

		compositeVolume = compositeVolume >> 8; // get upmost 8 bits
		if (compositeVolume)
			compositeVolume++; // round up in case result wasn't 0

		compositeVolume = compositeVolume * _virtualFmVoices[virtualFmVoice].currentVelocity * 2;
		compositeVolume = compositeVolume >> 8; // get upmost 8 bits
		if (compositeVolume)
			compositeVolume++; // round up in case result wasn't 0
	}

	if (registerUpdateFlags & kMilesAdLibUpdateFlags_Reg_20) {
		// Amplitude Modulation / Vibrato / Envelope Generator Type / Keyboard Scaling Rate / Modulator Frequency Multiple
		byte reg20op1 = instrumentPtr->reg20op1;
		byte reg20op2 = instrumentPtr->reg20op2;

		if (_midiChannels[midiChannel].currentModulation >= 64) {
			// set bit 6 (Vibrato)
			reg20op1 |= 0x40;
			reg20op2 |= 0x40;
		}
		setRegister(0x20 + op1Reg, reg20op1);
		setRegister(0x20 + op2Reg, reg20op2);
	}

	if (registerUpdateFlags & kMilesAdLibUpdateFlags_Reg_40) {
		// Volume (Level Key Scaling / Total Level)
		byte reg40op1 = instrumentPtr->reg40op1;
		byte reg40op2 = instrumentPtr->reg40op2;

		uint16 volumeOp1 = (~reg40op1) & 0x3F;
		uint16 volumeOp2 = (~reg40op2) & 0x3F;

		if (instrumentPtr->regC0 & 1) {
			// operator 2 enabled
			// scale volume factor
			volumeOp1 = (volumeOp1 * compositeVolume) / 127;
			// 2nd operator always scaled
		}

		volumeOp2 = (volumeOp2 * compositeVolume) / 127;

		volumeOp1 = (~volumeOp1) & 0x3F; // negate it, so we get the proper value for the register
		volumeOp2 = (~volumeOp2) & 0x3F; // ditto
		reg40op1  = (reg40op1 & 0xC0) | volumeOp1; // keep "scaling level" and merge in our volume
		reg40op2  = (reg40op2 & 0xC0) | volumeOp2;

		setRegister(0x40 + op1Reg, reg40op1);
		setRegister(0x40 + op2Reg, reg40op2);
	}

	if (registerUpdateFlags & kMilesAdLibUpdateFlags_Reg_60) {
		// Attack Rate / Decay Rate
		// Sustain Level / Release Rate
		byte reg60op1 = instrumentPtr->reg60op1;
		byte reg60op2 = instrumentPtr->reg60op2;
		byte reg80op1 = instrumentPtr->reg80op1;
		byte reg80op2 = instrumentPtr->reg80op2;

		setRegister(0x60 + op1Reg, reg60op1);
		setRegister(0x60 + op2Reg, reg60op2);
		setRegister(0x80 + op1Reg, reg80op1);
		setRegister(0x80 + op2Reg, reg80op2);
	}

	if (registerUpdateFlags & kMilesAdLibUpdateFlags_Reg_E0) {
		// Waveform Select
		byte regE0op1 = instrumentPtr->regE0op1;
		byte regE0op2 = instrumentPtr->regE0op2;

		setRegister(0xE0 + op1Reg, regE0op1);
		setRegister(0xE0 + op2Reg, regE0op2);
	}

	if (registerUpdateFlags & kMilesAdLibUpdateFlags_Reg_C0) {
		// Feedback / Algorithm
		byte regC0 = instrumentPtr->regC0;

		if (_modeOPL3) {
			// Panning for OPL3
			byte panning = _midiChannels[midiChannel].currentPanning;

			if (panning <= MILES_ADLIB_STEREO_PANNING_THRESHOLD_LEFT) {
				regC0 |= 0x20; // left speaker only
			} else if (panning >= MILES_ADLIB_STEREO_PANNING_THRESHOLD_RIGHT) {
				regC0 |= 0x10; // right speaker only
			} else {
				regC0 |= 0x30; // center
			}
		}

		setRegister(0xC0 + channelReg, regC0);
	}

	if (registerUpdateFlags & kMilesAdLibUpdateFlags_Reg_A0) {
		// Frequency / Key-On
		// Octave / F-Number / Key-On
		if (!keyOn) {
			// turn off note
			byte regB0 = _physicalFmVoices[physicalFmVoice].currentB0hReg & 0x1F; // remove bit 5 "key on"
			setRegister(0xB0 + channelReg, regB0);

		} else {
			// turn on note, calculate frequency, octave...
			int16 pitchBender = _midiChannels[midiChannel].currentPitchBender;
			byte  pitchRange = _midiChannels[midiChannel].currentPitchRange;
			int16 currentNote = _virtualFmVoices[virtualFmVoice].currentNote;
			int16 physicalNote = 0;
			int16 halfTone = 0;
			uint16 frequency = 0;
			uint16 frequencyIdx = 0;
			byte   octave = 0;

			pitchBender -= 0x2000;
			pitchBender = pitchBender >> 5; // divide by 32
			pitchBender = pitchBender * pitchRange; // pitchrange 12: now +0x0C00 to -0xC00
			// difference between Miles Audio 2 + 3
			// Miles Audio 2 used a pitch range of 12, which was basically hardcoded
			// Miles Audio 3 used an array, which got set by control change events

			currentNote += _virtualFmVoices->currentTransposition;

			// Normalize note
			currentNote -= 24;
			do {
				currentNote += 12;
			} while (currentNote < 0);
			currentNote += 12;

			do {
				currentNote -= 12;
			} while (currentNote > 95);

			// combine note + pitchbender, also adjust by 8 for rounding
			currentNote = (currentNote << 8) + pitchBender + 8;

			currentNote = currentNote >> 4; // get actual note

			// Normalize
			currentNote -= (12 * 16);
			do {
				currentNote += (12 * 16);
			} while (currentNote < 0);

			currentNote += (12 * 16);
			do {
				currentNote -= (12 * 16);
			} while (currentNote > ((96 * 16) - 1));

			physicalNote = currentNote >> 4;

			halfTone = physicalNote % 12; // remainder of physicalNote / 12

			frequencyIdx = (halfTone << 4) + (currentNote & 0x0F);
			assert(frequencyIdx < sizeof(milesAdLibFrequencyLookUpTable));
			frequency = milesAdLibFrequencyLookUpTable[frequencyIdx];

			octave = (physicalNote / 12) - 1;

			if (frequency & 0x8000)
				octave++;

			if (octave & 0x80) {
				octave++;
				frequency = frequency >> 1;
			}

			byte regA0 = frequency & 0xFF;
			byte regB0 = ((frequency >> 8) & 0x03) | (octave << 2) | 0x20;

			setRegister(0xA0 + channelReg, regA0);
			setRegister(0xB0 + channelReg, regB0);

			_physicalFmVoices[physicalFmVoice].currentB0hReg = regB0;
		}
	}

	//warning("end of update voice");
}

void MidiDriver_Miles_AdLib::controlChange(byte midiChannel, byte controllerNumber, byte controllerValue) {
	uint16 registerUpdateFlags = kMilesAdLibUpdateFlags_None;

	switch (controllerNumber) {
	case MILES_CONTROLLER_SELECT_PATCH_BANK:
		//warning("patch bank channel %d, bank %x", midiChannel, controllerValue);
		_midiChannels[midiChannel].currentPatchBank = controllerValue;
		break;

	case MILES_CONTROLLER_PROTECT_VOICE:
		_midiChannels[midiChannel].currentVoiceProtection = controllerValue;
		break;

	case MILES_CONTROLLER_PROTECT_TIMBRE:
		// It seems that this can get ignored, because we don't cache timbres at all
		break;

	case MILES_CONTROLLER_MODULATION:
		_midiChannels[midiChannel].currentModulation = controllerValue;
		registerUpdateFlags = kMilesAdLibUpdateFlags_Reg_20;
		break;

	case MILES_CONTROLLER_VOLUME:
		_midiChannels[midiChannel].currentVolume = controllerValue;
		registerUpdateFlags = kMilesAdLibUpdateFlags_Reg_40;
		break;

	case MILES_CONTROLLER_EXPRESSION:
		_midiChannels[midiChannel].currentVolumeExpression = controllerValue;
		registerUpdateFlags = kMilesAdLibUpdateFlags_Reg_40;
		break;

	case MILES_CONTROLLER_PANNING:
		_midiChannels[midiChannel].currentPanning = controllerValue;
		if (_modeStereo) {
			// Update register only in case we are in stereo mode
			registerUpdateFlags = kMilesAdLibUpdateFlags_Reg_C0;
		}
		break;

	case MILES_CONTROLLER_SUSTAIN:
		_midiChannels[midiChannel].currentSustain = controllerValue;
		if (controllerValue < 64) {
			releaseSustain(midiChannel);
		}
		break;

	case MILES_CONTROLLER_PITCH_RANGE:
		// Miles Audio 3 feature
		_midiChannels[midiChannel].currentPitchRange = controllerValue;
		break;

	case MILES_CONTROLLER_RESET_ALL:
		_midiChannels[midiChannel].currentSustain = 0;
		releaseSustain(midiChannel);
		_midiChannels[midiChannel].currentModulation = 0;
		_midiChannels[midiChannel].currentVolumeExpression = 127;
		_midiChannels[midiChannel].currentPitchBender = MILES_PITCHBENDER_DEFAULT;
		registerUpdateFlags = kMilesAdLibUpdateFlags_Reg_20 | kMilesAdLibUpdateFlags_Reg_40 | kMilesAdLibUpdateFlags_Reg_A0;
		break;

	case MILES_CONTROLLER_ALL_NOTES_OFF:
		for (byte virtualFmVoice = 0; virtualFmVoice < _modeVirtualFmVoicesCount; virtualFmVoice++) {
			if (_virtualFmVoices[virtualFmVoice].inUse) {
				// used
				if (_virtualFmVoices[virtualFmVoice].actualMidiChannel == midiChannel) {
					// by our current MIDI channel -> noteOff
					noteOff(midiChannel, _virtualFmVoices[virtualFmVoice].currentNote);
				}
			}
		}
		break;

	default:
		//warning("MILES-ADLIB: Unsupported control change %d", controllerNumber);
		break;
	}

	if (registerUpdateFlags) {
		for (byte virtualFmVoice = 0; virtualFmVoice < _modeVirtualFmVoicesCount; virtualFmVoice++) {
			if (_virtualFmVoices[virtualFmVoice].inUse) {
				// used
				if (_virtualFmVoices[virtualFmVoice].actualMidiChannel == midiChannel) {
					// by our current MIDI channel -> update
					updatePhysicalFmVoice(virtualFmVoice, true, registerUpdateFlags);
				}
			}
		}
	}
}

void MidiDriver_Miles_AdLib::programChange(byte midiChannel, byte patchId) {
	const InstrumentEntry *instrumentPtr = NULL;
	byte patchBank = _midiChannels[midiChannel].currentPatchBank;

	//warning("patch channel %d, patch %x, bank %x", midiChannel, patchId, patchBank);

	// we check, if we actually have data for the requested instrument...
	instrumentPtr = searchInstrument(patchBank, patchId);
	if (!instrumentPtr) {
		warning("MILES-ADLIB: unknown instrument requested (%d, %d)", patchBank, patchId);
		return;
	}

	// and remember it in that case for the current MIDI-channel
	_midiChannels[midiChannel].currentInstrumentPtr = instrumentPtr;
}

const InstrumentEntry *MidiDriver_Miles_AdLib::searchInstrument(byte bankId, byte patchId) {
	const InstrumentEntry *instrumentPtr = _instrumentTablePtr;

	for (uint16 instrumentNr = 0; instrumentNr < _instrumentTableCount; instrumentNr++) {
		if ((instrumentPtr->bankId == bankId) && (instrumentPtr->patchId == patchId)) {
			return instrumentPtr;
		}
		instrumentPtr++;
	}

	return NULL;
}

void MidiDriver_Miles_AdLib::pitchBendChange(byte midiChannel, byte parameter1, byte parameter2) {
	// Miles Audio actually didn't shift parameter 2 1 down in here
	// which means in memory it used a 15-bit pitch bender, which also means the default was 0x4000
	if ((parameter1 & 0x80) || (parameter2 & 0x80)) {
		warning("MILES-ADLIB: invalid pitch bend change");
		return;
	}
	_midiChannels[midiChannel].currentPitchBender = parameter1 | (parameter2 << 7);
}

void MidiDriver_Miles_AdLib::setRegister(int reg, int value) {
	if (!(reg & 0x100)) {
		_opl->write(0x220, reg);
		_opl->write(0x221, value);
		//warning("OPL write %x %x (%d)", reg, value, value);
	} else {
		_opl->write(0x222, reg & 0xFF);
		_opl->write(0x223, value);
		//warning("OPL3 write %x %x (%d)", reg & 0xFF, value, value);
	}
}

uint32 MidiDriver_Miles_AdLib::property(int prop, uint32 param) {
	return 0;
}

MidiDriver *MidiDriver_Miles_AdLib_create(const Common::String &filenameAdLib, const Common::String &filenameOPL3, Common::SeekableReadStream *streamAdLib, Common::SeekableReadStream *streamOPL3) {
	// Load adlib instrument data from file SAMPLE.AD (OPL3: SAMPLE.OPL)
	Common::String              timbreFilename;
	Common::SeekableReadStream *timbreStream = nullptr;

	bool          preferOPL3 = false;

	Common::File *fileStream = new Common::File();
	uint32        fileSize = 0;
	uint32        fileDataOffset = 0;
	uint32        fileDataLeft = 0;


	uint32        streamSize = 0;
	byte         *streamDataPtr = nullptr;

	byte curBankId = 0;
	byte curPatchId = 0;

	InstrumentEntry *instrumentTablePtr = nullptr;
	uint16           instrumentTableCount = 0;
	InstrumentEntry *instrumentPtr = nullptr;
	uint32           instrumentOffset = 0;
	uint16           instrumentDataSize = 0;

	// Logic:
	// We prefer OPL3 timbre data in case OPL3 is available in ScummVM
	// If it's not or OPL3 timbre data is not available, we go for AdLib timbre data
	// And if OPL3 is not available in ScummVM and also AdLib timbre data is not available,
	// we then still go for OPL3 timbre data.
	//
	// Note: for most games OPL3 timbre data + AdLib timbre data is the same.
	//       And at least in theory we should still be able to use OPL3 timbre data even for AdLib.
	//       However there is a special OPL3-specific timbre format, which is currently not supported.
	//       In this case the error message "unsupported instrument size" should appear. I haven't found
	//       a game that uses it, which is why I haven't implemented it yet.

	if (OPL::Config::detect(OPL::Config::kOpl3) >= 0) {
		// OPL3 available, prefer OPL3 timbre data because of this
		preferOPL3 = true;
	}

	// Check if streams were passed to us and select one of them
	if ((streamAdLib) || (streamOPL3)) {
		// At least one stream was passed by caller
		if (preferOPL3) {
			// Prefer OPL3 timbre stream in case OPL3 is available
			timbreStream = streamOPL3;
		}
		if (!timbreStream) {
			// Otherwise prefer AdLib timbre stream first
			if (streamAdLib) {
				timbreStream = streamAdLib;
			} else {
				// If not available, use OPL3 timbre stream
				if (streamOPL3) {
					timbreStream = streamOPL3;
				}
			}
		}
	}

	// Now check if any filename was passed to us
	if ((!filenameAdLib.empty()) || (!filenameOPL3.empty())) {
		// If that's the case, check if one of those exists
		if (preferOPL3) {
			// OPL3 available
			if (!filenameOPL3.empty()) {
				if (fileStream->exists(filenameOPL3)) {
					// If OPL3 available, prefer OPL3 timbre file in case file exists
					timbreFilename = filenameOPL3;
				}
			}
			if (timbreFilename.empty()) {
				if (!filenameAdLib.empty()) {
					if (fileStream->exists(filenameAdLib)) {
						// otherwise use AdLib timbre file, if it exists
						timbreFilename = filenameAdLib;
					}
				}
			}
		} else {
			// OPL3 not available
			// Prefer the AdLib one for now
			if (!filenameAdLib.empty()) {
				if (fileStream->exists(filenameAdLib)) {
					// if AdLib file exists, use it
					timbreFilename = filenameAdLib;
				}
			}
			if (timbreFilename.empty()) {
				if (!filenameOPL3.empty()) {
					if (fileStream->exists(filenameOPL3)) {
						// if OPL3 file exists, use it
						timbreFilename = filenameOPL3;
					}
				}
			}
		}
		if (timbreFilename.empty() && (!timbreStream)) {
			// If none of them exists and also no stream was passed, we can't do anything about it
			if (!filenameAdLib.empty()) {
				if (!filenameOPL3.empty()) {
					error("MILES-ADLIB: could not open timbre file (%s or %s)", filenameAdLib.c_str(), filenameOPL3.c_str());
				} else {
					error("MILES-ADLIB: could not open timbre file (%s)", filenameAdLib.c_str());
				}
			} else {
				error("MILES-ADLIB: could not open timbre file (%s)", filenameOPL3.c_str());
			}
		}
	}

	if (!timbreFilename.empty()) {
		// Filename was passed to us and file exists (this is the common case for most games)
		// We prefer this situation

		if (!fileStream->open(timbreFilename))
			error("MILES-ADLIB: could not open timbre file (%s)", timbreFilename.c_str());

		streamSize = fileStream->size();

		streamDataPtr = new byte[streamSize];

		if (fileStream->read(streamDataPtr, streamSize) != streamSize)
			error("MILES-ADLIB: error while reading timbre file (%s)", timbreFilename.c_str());
		fileStream->close();

	} else if (timbreStream) {
		// Timbre data was passed directly (possibly read from resource file by caller)
		// Currently used by "Amazon Guardians of Eden", "Simon 2" and "Return To Zork"
		streamSize = timbreStream->size();

		streamDataPtr = new byte[streamSize];

		if (timbreStream->read(streamDataPtr, streamSize) != streamSize)
			error("MILES-ADLIB: error while reading timbre stream");

	} else {
		error("MILES-ADLIB: timbre filenames nor timbre stream were passed");
	}

	delete fileStream;

	// File is like this:
	// [patch:BYTE] [bank:BYTE] [patchoffset:UINT32]
	// ...
	// until patch + bank are both 0xFF, which signals end of header

	// First we check how many entries there are
	fileDataOffset = 0;
	fileDataLeft = streamSize;
	while (1) {
		if (fileDataLeft < 6)
			error("MILES-ADLIB: unexpected EOF in instrument file");

		curPatchId = streamDataPtr[fileDataOffset++];
		curBankId  = streamDataPtr[fileDataOffset++];

		if ((curBankId == 0xFF) && (curPatchId == 0xFF))
			break;

		fileDataOffset += 4; // skip over offset
		instrumentTableCount++;
	}

	if (instrumentTableCount == 0)
		error("MILES-ADLIB: no instruments in instrument file");

	// Allocate space for instruments
	instrumentTablePtr = new InstrumentEntry[instrumentTableCount];

	// Now actually read all entries
	instrumentPtr = instrumentTablePtr;

	fileDataOffset = 0;
	fileDataLeft = fileSize;
	while (1) {
		curPatchId = streamDataPtr[fileDataOffset++];
		curBankId  = streamDataPtr[fileDataOffset++];

		if ((curBankId == 0xFF) && (curPatchId == 0xFF))
			break;

		instrumentOffset = READ_LE_UINT32(streamDataPtr + fileDataOffset);
		fileDataOffset += 4;

		instrumentPtr->bankId = curBankId;
		instrumentPtr->patchId = curPatchId;

		instrumentDataSize = READ_LE_UINT16(streamDataPtr + instrumentOffset);
		if (instrumentDataSize != 14)
			error("MILES-ADLIB: unsupported instrument size");

		instrumentPtr->transposition = (signed char)streamDataPtr[instrumentOffset + 2];
		instrumentPtr->reg20op1 = streamDataPtr[instrumentOffset + 3];
		instrumentPtr->reg40op1 = streamDataPtr[instrumentOffset + 4];
		instrumentPtr->reg60op1 = streamDataPtr[instrumentOffset + 5];
		instrumentPtr->reg80op1 = streamDataPtr[instrumentOffset + 6];
		instrumentPtr->regE0op1 = streamDataPtr[instrumentOffset + 7];
		instrumentPtr->regC0    = streamDataPtr[instrumentOffset + 8];
		instrumentPtr->reg20op2 = streamDataPtr[instrumentOffset + 9];
		instrumentPtr->reg40op2 = streamDataPtr[instrumentOffset + 10];
		instrumentPtr->reg60op2 = streamDataPtr[instrumentOffset + 11];
		instrumentPtr->reg80op2 = streamDataPtr[instrumentOffset + 12];
		instrumentPtr->regE0op2 = streamDataPtr[instrumentOffset + 13];

		// Instrument read, next instrument please
		instrumentPtr++;
	}

	// Free instrument file/stream data
	delete[] streamDataPtr;

	return new MidiDriver_Miles_AdLib(instrumentTablePtr, instrumentTableCount);
}

} // End of namespace Audio