summaryrefslogtreecommitdiffstatshomepage
path: root/src/mame/audio/snes.c
blob: a9adb56ab7516df075d40e1b3dfe6ed78b0f46b1 (plain) (blame)
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
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
/***************************************************************************

  snes.c

  File to handle the sound emulation of the Nintendo Super NES.

  By R. Belmont, adapted from OpenSPC 0.3.99 by Brad Martin with permission.
  Thanks to Brad and also to Charles Bilyu? of SNeESe.

  OpenSPC's license terms (the LGPL) follow:

 ---------------------------------------------------------------------------

  Copyright Brad Martin.

  OpenSPC is free software; you can redistribute it and/or modify
  it under the terms of the GNU Lesser General Public License as published by
  the Free Software Foundation; either version 2 of the License, or
  (at your option) any later version.

  OpenSPC 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 Lesser General Public License for more details.

***************************************************************************/

#include <math.h>
#include "driver.h"
#include "streams.h"
#include "includes/snes.h"

static struct
{
	UINT8 enabled;
	UINT16 counter;
	emu_timer *timer;
} timers[3];
static sound_stream *channel;
static UINT8 DSPregs[256];		/* DSP registers */
static UINT8 snes_ipl_region[64];	/* SPC top 64 bytes */

static const int gauss[]=
{
	0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000,
	0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000,
	0x001, 0x001, 0x001, 0x001, 0x001, 0x001, 0x001, 0x001,
	0x001, 0x001, 0x001, 0x002, 0x002, 0x002, 0x002, 0x002,
	0x002, 0x002, 0x003, 0x003, 0x003, 0x003, 0x003, 0x004,
	0x004, 0x004, 0x004, 0x004, 0x005, 0x005, 0x005, 0x005,
	0x006, 0x006, 0x006, 0x006, 0x007, 0x007, 0x007, 0x008,
	0x008, 0x008, 0x009, 0x009, 0x009, 0x00A, 0x00A, 0x00A,
	0x00B, 0x00B, 0x00B, 0x00C, 0x00C, 0x00D, 0x00D, 0x00E,
	0x00E, 0x00F, 0x00F, 0x00F, 0x010, 0x010, 0x011, 0x011,
	0x012, 0x013, 0x013, 0x014, 0x014, 0x015, 0x015, 0x016,
	0x017, 0x017, 0x018, 0x018, 0x019, 0x01A, 0x01B, 0x01B,
	0x01C, 0x01D, 0x01D, 0x01E, 0x01F, 0x020, 0x020, 0x021,
	0x022, 0x023, 0x024, 0x024, 0x025, 0x026, 0x027, 0x028,
	0x029, 0x02A, 0x02B, 0x02C, 0x02D, 0x02E, 0x02F, 0x030,
	0x031, 0x032, 0x033, 0x034, 0x035, 0x036, 0x037, 0x038,
	0x03A, 0x03B, 0x03C, 0x03D, 0x03E, 0x040, 0x041, 0x042,
	0x043, 0x045, 0x046, 0x047, 0x049, 0x04A, 0x04C, 0x04D,
	0x04E, 0x050, 0x051, 0x053, 0x054, 0x056, 0x057, 0x059,
	0x05A, 0x05C, 0x05E, 0x05F, 0x061, 0x063, 0x064, 0x066,
	0x068, 0x06A, 0x06B, 0x06D, 0x06F, 0x071, 0x073, 0x075,
	0x076, 0x078, 0x07A, 0x07C, 0x07E, 0x080, 0x082, 0x084,
	0x086, 0x089, 0x08B, 0x08D, 0x08F, 0x091, 0x093, 0x096,
	0x098, 0x09A, 0x09C, 0x09F, 0x0A1, 0x0A3, 0x0A6, 0x0A8,
	0x0AB, 0x0AD, 0x0AF, 0x0B2, 0x0B4, 0x0B7, 0x0BA, 0x0BC,
	0x0BF, 0x0C1, 0x0C4, 0x0C7, 0x0C9, 0x0CC, 0x0CF, 0x0D2,
	0x0D4, 0x0D7, 0x0DA, 0x0DD, 0x0E0, 0x0E3, 0x0E6, 0x0E9,
	0x0EC, 0x0EF, 0x0F2, 0x0F5, 0x0F8, 0x0FB, 0x0FE, 0x101,
	0x104, 0x107, 0x10B, 0x10E, 0x111, 0x114, 0x118, 0x11B,
	0x11E, 0x122, 0x125, 0x129, 0x12C, 0x130, 0x133, 0x137,
	0x13A, 0x13E, 0x141, 0x145, 0x148, 0x14C, 0x150, 0x153,
	0x157, 0x15B, 0x15F, 0x162, 0x166, 0x16A, 0x16E, 0x172,
	0x176, 0x17A, 0x17D, 0x181, 0x185, 0x189, 0x18D, 0x191,
	0x195, 0x19A, 0x19E, 0x1A2, 0x1A6, 0x1AA, 0x1AE, 0x1B2,
	0x1B7, 0x1BB, 0x1BF, 0x1C3, 0x1C8, 0x1CC, 0x1D0, 0x1D5,
	0x1D9, 0x1DD, 0x1E2, 0x1E6, 0x1EB, 0x1EF, 0x1F3, 0x1F8,
	0x1FC, 0x201, 0x205, 0x20A, 0x20F, 0x213, 0x218, 0x21C,
	0x221, 0x226, 0x22A, 0x22F, 0x233, 0x238, 0x23D, 0x241,
	0x246, 0x24B, 0x250, 0x254, 0x259, 0x25E, 0x263, 0x267,
	0x26C, 0x271, 0x276, 0x27B, 0x280, 0x284, 0x289, 0x28E,
	0x293, 0x298, 0x29D, 0x2A2, 0x2A6, 0x2AB, 0x2B0, 0x2B5,
	0x2BA, 0x2BF, 0x2C4, 0x2C9, 0x2CE, 0x2D3, 0x2D8, 0x2DC,
	0x2E1, 0x2E6, 0x2EB, 0x2F0, 0x2F5, 0x2FA, 0x2FF, 0x304,
	0x309, 0x30E, 0x313, 0x318, 0x31D, 0x322, 0x326, 0x32B,
	0x330, 0x335, 0x33A, 0x33F, 0x344, 0x349, 0x34E, 0x353,
	0x357, 0x35C, 0x361, 0x366, 0x36B, 0x370, 0x374, 0x379,
	0x37E, 0x383, 0x388, 0x38C, 0x391, 0x396, 0x39B, 0x39F,
	0x3A4, 0x3A9, 0x3AD, 0x3B2, 0x3B7, 0x3BB, 0x3C0, 0x3C5,
	0x3C9, 0x3CE, 0x3D2, 0x3D7, 0x3DC, 0x3E0, 0x3E5, 0x3E9,
	0x3ED, 0x3F2, 0x3F6, 0x3FB, 0x3FF, 0x403, 0x408, 0x40C,
	0x410, 0x415, 0x419, 0x41D, 0x421, 0x425, 0x42A, 0x42E,
	0x432, 0x436, 0x43A, 0x43E, 0x442, 0x446, 0x44A, 0x44E,
	0x452, 0x455, 0x459, 0x45D, 0x461, 0x465, 0x468, 0x46C,
	0x470, 0x473, 0x477, 0x47A, 0x47E, 0x481, 0x485, 0x488,
	0x48C, 0x48F, 0x492, 0x496, 0x499, 0x49C, 0x49F, 0x4A2,
	0x4A6, 0x4A9, 0x4AC, 0x4AF, 0x4B2, 0x4B5, 0x4B7, 0x4BA,
	0x4BD, 0x4C0, 0x4C3, 0x4C5, 0x4C8, 0x4CB, 0x4CD, 0x4D0,
	0x4D2, 0x4D5, 0x4D7, 0x4D9, 0x4DC, 0x4DE, 0x4E0, 0x4E3,
	0x4E5, 0x4E7, 0x4E9, 0x4EB, 0x4ED, 0x4EF, 0x4F1, 0x4F3,
	0x4F5, 0x4F6, 0x4F8, 0x4FA, 0x4FB, 0x4FD, 0x4FF, 0x500,
	0x502, 0x503, 0x504, 0x506, 0x507, 0x508, 0x50A, 0x50B,
	0x50C, 0x50D, 0x50E, 0x50F, 0x510, 0x511, 0x511, 0x512,
	0x513, 0x514, 0x514, 0x515, 0x516, 0x516, 0x517, 0x517,
	0x517, 0x518, 0x518, 0x518, 0x518, 0x518, 0x519, 0x519
};

/*========== DEFINES ==========*/

#undef DEBUG
#undef DBG_KEY
#undef DBG_ENV
#undef DBG_PMOD
#undef DBG_BRR
#undef DBG_ECHO
#undef DBG_INTRP

#undef NO_PMOD
#undef NO_ECHO

#define CPU_RATE        ( 1024000 )
#define SAMP_FREQ       ( 32000 )

/*========== VARIABLES ==========*/

static int                     keyed_on;
static int                     keys;       /* 8-bits for 8 voices          */
static voice_state_type        voice_state[ 8 ];

/* Noise stuff */
static int		                noise_cnt;
static int                     noise_lev;

/* These are for the FIR echo filter */
#ifndef NO_ECHO
static short            FIRlbuf[ 8 ];
static short            FIRrbuf[ 8 ];
static int              FIRptr;
static int              echo_ptr;
#endif

/*========== CONSTANTS ==========*/

/* Original SPC DSP took samples 32000 times a second, which is once every
   (1024000/32000 = 32) cycles. */
#ifdef UNUSED_DEFINITION
static const int               TS_CYC = CPU_RATE / SAMP_FREQ;
#endif

/* Ptrs to Gaussian table */
static const int *const G1 = &gauss[ 256 ];
static const int *const G2 = &gauss[ 512 ];
static const int *const G3 = &gauss[ 255 ];
static const int *const G4 = &gauss[ -1  ];

static const int        mask = 0xFF;

/* This table is for envelope timing.  It represents the number of counts
   that should be subtracted from the counter each sample period (32kHz).
   The counter starts at 30720 (0x7800). */
static const int        CNT_INIT = 0x7800;
static const int        ENVCNT[ 0x20 ]
  = {
    0x0000, 0x000F, 0x0014, 0x0018, 0x001E, 0x0028, 0x0030, 0x003C,
    0x0050, 0x0060, 0x0078, 0x00A0, 0x00C0, 0x00F0, 0x0140, 0x0180,
    0x01E0, 0x0280, 0x0300, 0x03C0, 0x0500, 0x0600, 0x0780, 0x0A00,
    0x0C00, 0x0F00, 0x1400, 0x1800, 0x1E00, 0x2800, 0x3C00, 0x7800
    };

/*========== MACROS ==========*/

/* Make reading the ADSR code easier */
#define SL( v )         ( DSPregs[ ( ( v ) << 4 ) + 6 ] >> 5 )
                                    /* Returns SUSTAIN level        */
#define SR( v )         ( DSPregs[ ( ( v ) << 4 ) + 6 ] & 0x1F )
                                    /* Returns SUSTAIN rate         */

/* Handle endianness */
#define LEtoME16( x ) LITTLE_ENDIANIZE_INT16(x)
#define MEtoLE16( x ) LITTLE_ENDIANIZE_INT16(x)

/*========== PROCEDURES ==========*/

static int AdvanceEnvelope          /* Run envelope step & retn ENVX*/
    (
    int                 v           /* Voice to process envelope for*/
    );

static STREAM_UPDATE( snes_sh_update );

/* Privately shared functions (for internal library use only) */

/***** DSP_Reset *****/

static void DSP_Reset                      /* Reset emulated DSP           */
    ( void )
{
int                     i;

#ifdef DEBUG
fprintf( stderr,"DSP_Reset\n" );
#endif

for( i = 0; i < 8; i++ )
    {
#ifndef NO_ECHO
    FIRlbuf[ i ]            = 0;
    FIRrbuf[ i ]            = 0;
#endif
    voice_state[ i ].on_cnt = 0;
    }

#ifndef NO_ECHO
FIRptr   = 0;
echo_ptr = 0;
#endif
keys             = 0;
keyed_on         = 0;
noise_cnt        = 0;
noise_lev        = 0x4000;
DSPregs[ 0x6C ] |= 0xE0;
DSPregs[ 0x4C ]  = 0;
DSPregs[ 0x5C ]  = 0;

}   /* DSP_Reset() */


/***** DSP_Update *****/

static void DSP_Update                     /* Mix one sample of audio      */
    (
    short *             sound_ptr   /* Pointer to mix audio into    */
    )
{
int                     V;
#ifndef NO_ECHO
int                     echo_base;
int                     echol;
int                     echor;
#endif
int                     envx;
int                     m;
int                     outl;
int                     outr;
signed long             outx;       /* Smpl height (must be signed) */
src_dir_type *          sd;
int                     v;
int                     vl;
voice_state_type *      vp;
int                     vr;

sd = ( src_dir_type * )&spc_ram[ ( int )DSPregs[ 0x5D ] << 8 ];

/* Check for reset */
if( DSPregs[ 0x6C ] & 0x80 )
    {
    DSP_Reset();
    }

/* Here we check for keys on/off.  Docs say that successive writes to KON/KOF
   must be separated by at least 2 Ts periods or risk being neglected.
   Therefore DSP only looks at these during an update, and not at the time of
   the write.  Only need to do this once however, since the regs haven't
   changed over the whole period we need to catch up with. */
#ifdef DBG_KEY
DSPregs[ 0x4C ] &= mask;
#endif

/* Keying on a voice resets that bit in ENDX */
DSPregs[ 0x7C ] &= ~DSPregs[ 0x4C ];

/* Question: what is the expected behavior when pitch modulation is enabled on
   voice 0?  Jurassic Park 2 does this.  For now, using outx of zero for first
   voice. */
outx = 0;
/* Same table for noise and envelope */
noise_cnt -= ENVCNT[ DSPregs[ 0x6C ] & 0x1F ];
if( noise_cnt <= 0 )
    {
    noise_cnt = CNT_INIT;
    noise_lev = ( ( ( noise_lev << 13 ) ^ ( noise_lev << 14 ) ) & 0x4000 )
              | ( noise_lev >> 1                                         );
    }
outl  = 0;
outr  = 0;
#ifndef NO_ECHO
echol = 0;
echor = 0;
#endif
for( v = 0, m = 1, V = 0; v < 8; v++, V += 16, m <<= 1 )
    {
    vp = &voice_state[ v ];
    if( vp->on_cnt && ( --vp->on_cnt == 0 ) )
        {
        /* Voice was keyed on */
        keys       |= m;
        keyed_on   |= m;
        vl          = DSPregs[ ( v<<4 ) + 4 ];
        vp->samp_id = *( UINT32 * )&sd[ vl ];
        vp->mem_ptr = LEtoME16( sd[ vl ].vptr );

#ifdef DBG_KEY
        fprintf(
               stderr,
               "Keying on voice %d, samp=0x%04X (0x%02X)\n",
               v,
               vp->mem_ptr,
               vl
               );
#endif

        vp->header_cnt = 0;
        vp->half       = 0;
        vp->envx       = 0;
        vp->end        = 0;
        vp->sampptr    = 0;
        vp->mixfrac    = 3 * 4096;

        /* NOTE: Real SNES does *not* appear to initialize the envelope
           counter to anything in particular.  The first cycle always seems to
           come at a random time sooner than expected; as yet, I have been
           unable to find any pattern.  I doubt it will matter though, so
           we'll go ahead and do the full time for now. */
        vp->envcnt   = CNT_INIT;
        vp->envstate = ATTACK;
        }

    if( DSPregs[ 0x4C ] & m & ~DSPregs[ 0x5C ] )
        {
        /* Voice doesn't come on if key off is set */
        DSPregs[ 0x4C ] &= ~m;
        vp->on_cnt       = 8;

#ifdef DBG_KEY
        fprintf( stderr, "Key on set for voice %d\n", v );
#endif
        }

    if( keys & DSPregs[ 0x5C ] & m )
        {
        /* Voice was keyed off */
        vp->envstate = RELEASE;
        vp->on_cnt   = 0;

#ifdef DBG_KEY
        fprintf( stderr, "Keying off voice %d\n", v );
#endif
        }

    if( !( keys & m & mask ) || ( ( envx = AdvanceEnvelope( v ) ) < 0 ) )
        {
        DSPregs[ V + 8 ] = 0;
        DSPregs[ V + 9 ] = 0;
        outx             = 0;
        continue;
        }

    vp->pitch = LEtoME16( *( ( UINT16 * )&DSPregs[ V + 2 ] ) )
              & 0x3FFF;

#ifndef NO_PMOD
    /* Pitch mod uses OUTX from last voice for this one.  Luckily we haven't
       modified OUTX since it was used for last voice. */
    if(DSPregs[ 0x2D ] & m )
        {
#ifdef DBG_PMOD
        fprintf(
               stderr,
               "Pitch Modulating voice %d, outx=%ld, old pitch=%d, ",
               v,
               outx,
               vp->pitch
               );
#endif
        vp->pitch = ( vp->pitch * ( outx + 32768 ) ) >> 15;
        }
#endif

#ifdef DBG_PMOD
    fprintf( stderr, "pitch=%d\n", vp->pitch );
#endif

    for( ; vp->mixfrac >= 0; vp->mixfrac -= 4096 )
        {
        /* This part performs the BRR decode 'on-the-fly'.  This is more
           correct than the old way, which could be fooled if the data and/or
           the loop point changed while the sample was playing, or if the BRR
           decode didn't produce the same result every loop because of the
           filters.  The event interface still has no chance of keeping up
           with those kinds of tricks, though. */
        if( !vp->header_cnt )
            {
            if( vp->end & 1 )
                {
                /* Docs say ENDX bit is set when decode of block with source
                   end flag set is done.  Does this apply to looping samples?
                   Some info I've seen suggests yes. */
                DSPregs[ 0x7C ] |= m;
                if( vp->end & 2 )
                    {
                    vp->mem_ptr = LEtoME16( sd[ DSPregs[ V + 4 ] ].lptr );

#ifdef DBG_BRR
                    fprintf(
                           stderr,
                           "BRR looping to 0x%04X\n",
                           vp->mem_ptr
                           );
#endif
                    }
                else
                    {
#ifdef DBG_KEY
                    fprintf( stderr, "BRR decode end, voice %d\n", v );
#endif

                    keys &= ~m;
                    DSPregs[ V + 8 ] = 0;
                    vp->envx         = 0;
                    while( vp->mixfrac >= 0 )
                        {
                        vp->sampbuf[ vp->sampptr ] = 0;
                        outx         = 0;
                        vp->sampptr  = ( vp->sampptr + 1 ) & 3;
                        vp->mixfrac -= 4096;
                        }
                    break;
                    }
                }
            vp->header_cnt = 8;
            vl             = ( UINT8 )spc_ram[ vp->mem_ptr++ ];
            vp->range      = vl >> 4;
            vp->end        = vl & 3;
            vp->filter     = ( vl & 12 ) >> 2;

#ifdef DBG_BRR
            fprintf(
                   stderr,
                   "V%d: header read, range=%d, end=%d, filter=%d\n",
                   v,
                   vp->range,
                   vp->end,
                   vp->filter
                   );
#endif
            }
        if( vp->half == 0 )
            {
            vp->half = 1;
            outx     = ( ( signed char )spc_ram[ vp->mem_ptr ] ) >> 4;
            }
        else
            {
            vp->half = 0;
            /* Funkiness to get 4-bit signed to carry through */
            outx   = ( signed char )( spc_ram[ vp->mem_ptr++ ] << 4 );
            outx >>= 4;
            vp->header_cnt--;
            }

#ifdef DBG_BRR
        fprintf(
               stderr,
               "V%d: nybble=%X, ptr=%04X, smp1=%d, smp2=%d\n",
               v,
               outx & 0xF,
               vp->mem_ptr,
               vp->smp1,
               vp->smp2
               );
#endif

        /* For invalid ranges (D,E,F): if the nybble is negative, the result
           is F000.  If positive, 0000.  Nothing else like previous range,
           etc. seems to have any effect.  If range is valid, do the shift
           normally.  Note these are both shifted right once to do the filters
           properly, but the output will be shifted back again at the end. */
        if( vp->range <= 0xC )
            {
            outx = ( outx << vp->range ) >> 1;
            }
        else
            {
            outx &= ~0x7FF;

#ifdef DBG_BRR
            fprintf( stderr, "V%d: invalid range! (%X)\n", v, vp->range );
#endif
            }

#ifdef DBG_BRR
        fprintf(
               stderr,
               "V%d: shifted delta=%04X\n",
               v,
               ( UINT16 )outx
               );
#endif

        switch( vp->filter )
            {
            case 0:
                break;

            case 1:
                outx += ( vp->smp1 >> 1 ) + ( ( -vp->smp1 ) >> 5 );
                break;

            case 2:
                outx += vp->smp1
                      + ( ( -( vp->smp1 + ( vp->smp1 >> 1 ) ) ) >> 5 )
                      - ( vp->smp2 >> 1 ) + ( vp->smp2 >> 5 );
                break;

            case 3:
                outx += vp->smp1
                      + ( ( -( vp->smp1 + ( vp->smp1 << 2 )
                             + ( vp->smp1 << 3 )            ) ) >> 7 )
                      - ( vp->smp2 >> 1                              )
                      + ( ( vp->smp2 + ( vp->smp2 >> 1 )      ) >> 4 );
                break;
            }

        if( outx < ( signed short )0x8000 )
            {
            outx = ( signed short )0x8000;
            }
        else if( outx > ( signed short )0x7FFF )
            {
            outx = ( signed short )0x7FFF;
            }

#ifdef DBG_BRR
        fprintf(
               stderr,
               "V%d: filter + delta=%04X\n",
               v,
               ( UINT16 )outx
               );
#endif

        vp->smp2                   = ( signed short )vp->smp1;
        vp->smp1                   = ( signed short )( outx << 1 );
        vp->sampbuf[ vp->sampptr ] = vp->smp1;

#ifdef DBG_BRR
        fprintf(
               stderr,
               "V%d: final output: %04X\n",
               v,
               vp->sampbuf[ vp->sampptr ]
               );
#endif

        vp->sampptr = ( vp->sampptr + 1 ) & 3;
        }

    if(DSPregs[ 0x3D ] & m )
        {
#ifdef DBG_PMOD
        fprintf( stderr, "Noise enabled, voice %d\n", v );
#endif
        outx = ( signed short )( noise_lev << 1 );
        }
    else
        {
        /* Perform 4-Point Gaussian interpolation.  Take an approximation of a
           Gaussian bell-curve, and move it through the sample data at a rate
           determined by the pitch.  The sample output at any given time is
           the sum of the products of each input sample point with the value
           of the bell-curve corresponding to that point. */
        vl  = vp->mixfrac >> 4;
        vr  = ( ( G4[ -vl ] * vp->sampbuf[ vp->sampptr ] ) >> 11 ) & ~1;
        vr += ( ( G3[ -vl ]
                * vp->sampbuf[ ( vp->sampptr + 1 ) & 3 ] ) >> 11 ) & ~1;
        vr += ( ( G2[ vl ]
                * vp->sampbuf[ ( vp->sampptr + 2 ) & 3 ] ) >> 11 ) & ~1;

        /* This is to do the wrapping properly.  Based on my tests with the
           SNES, it appears clipping is done only if it is the fourth addition
           that would cause a wrap.  If it has already wrapped before the
           fourth addition, it is not clipped. */
        vr  = ( signed short )vr;
        vr += ( ( G1[ vl ]
                * vp->sampbuf[ ( vp->sampptr + 3 ) & 3 ] ) >> 11 ) & ~1;
        if( vr > 32767 )
            {
            vr = 32767;
            }
        else if( vr < -32768 )
            {
            vr = -32768;
            }
        outx = ( signed short )vr;

#ifdef DBG_INTRP
        fprintf(
               stderr,
               "V%d: mixfrac=%d: [%d]*%d + [%d]*%d + [%d]*%d + [%d]*%d = %d\n",
               v,
               vl,
               G1[ vl ],
               vp->sampbuf[ ( vp->sampptr + 3 ) & 3 ],
               G2[ vl ],
               vp->sampbuf[ ( vp->sampptr + 2 ) & 3 ],
               G3[ -vl ],
               vp->sampbuf[ ( vp->sampptr + 1 ) & 3 ],
               G4[ -vl ],
               vp->sampbuf[ vp->sampptr ],
               outx
               );
#endif
        }

    /* Advance the sample position for next update. */
    vp->mixfrac += vp->pitch;

    outx = ( ( outx * envx ) >> 11 ) & ~1;
    DSPregs[ V + 9 ] = outx >> 8;

    vl = ( ( ( int )( signed char )DSPregs[ V     ] ) * outx ) >> 7;
    vr = ( ( ( int )( signed char )DSPregs[ V + 1 ] ) * outx ) >> 7;
    outl += vl;
    outr += vr;
    if( DSPregs[ 0x4D ] & m )
        {
#ifndef NO_ECHO
        echol += vl;
        echor += vr;
#endif
        }
    }
outl = ( outl * ( signed char )DSPregs[ 0x0C ] ) >> 7;
outr = ( outr * ( signed char )DSPregs[ 0x1C ] ) >> 7;

#ifndef NO_ECHO
/* Perform echo.  First, read mem at current location, and put those samples
   into the FIR filter queue. */
#ifdef DBG_ECHO
fprintf(
       stderr,
       "Echo delay=%dms, feedback=%d%%\n",
       DSPregs[ 0x7D ] * 16,
       ( ( signed char )DSPregs[ 0x0D ] * 100 ) / 0x7F
       );
#endif

echo_base = ( ( DSPregs[ 0x6D ] << 8 ) + echo_ptr ) & 0xFFFF;
FIRlbuf[ FIRptr ]
  = ( signed short )LEtoME16(
                            *( UINT16 * )
                              &spc_ram[ echo_base ]
                            );
FIRrbuf[ FIRptr ]
  = ( signed short )LEtoME16(
                            *( UINT16 * )
                              &spc_ram[ echo_base + sizeof( short ) ]
                            );

/* Now, evaluate the FIR filter, and add the results into the final output. */
vl     = FIRlbuf[ FIRptr ] * ( signed char )DSPregs[ 0x7F ];
vr     = FIRrbuf[ FIRptr ] * ( signed char )DSPregs[ 0x7F ];
FIRptr = ( FIRptr + 1 ) & 7;
vl    += FIRlbuf[ FIRptr ] * ( signed char )DSPregs[ 0x6F ];
vr    += FIRrbuf[ FIRptr ] * ( signed char )DSPregs[ 0x6F ];
FIRptr = ( FIRptr + 1 ) & 7;
vl    += FIRlbuf[ FIRptr ] * ( signed char )DSPregs[ 0x5F ];
vr    += FIRrbuf[ FIRptr ] * ( signed char )DSPregs[ 0x5F ];
FIRptr = ( FIRptr + 1 ) & 7;
vl    += FIRlbuf[ FIRptr ] * ( signed char )DSPregs[ 0x4F ];
vr    += FIRrbuf[ FIRptr ] * ( signed char )DSPregs[ 0x4F ];
FIRptr = ( FIRptr + 1 ) & 7;
vl    += FIRlbuf[ FIRptr ] * ( signed char )DSPregs[ 0x3F ];
vr    += FIRrbuf[ FIRptr ] * ( signed char )DSPregs[ 0x3F ];
FIRptr = ( FIRptr + 1 ) & 7;
vl    += FIRlbuf[ FIRptr ] * ( signed char )DSPregs[ 0x2F ];
vr    += FIRrbuf[ FIRptr ] * ( signed char )DSPregs[ 0x2F ];
FIRptr = ( FIRptr + 1 ) & 7;
vl    += FIRlbuf[ FIRptr ] * ( signed char )DSPregs[ 0x1F ];
vr    += FIRrbuf[ FIRptr ] * ( signed char )DSPregs[ 0x1F ];
FIRptr = ( FIRptr + 1 ) & 7;
vl    += FIRlbuf[ FIRptr ] * ( signed char )DSPregs[ 0x0F ];
vr    += FIRrbuf[ FIRptr ] * ( signed char )DSPregs[ 0x0F ];

#ifdef DBG_ECHO
fprintf(
       stderr,
       "FIR Coefficients: %02X %02X %02X %02X %02X %02X %02X %02X\n",
       DSPregs[ 0x0F ],
       DSPregs[ 0x1F ],
       DSPregs[ 0x2F ],
       DSPregs[ 0x3F ],
       DSPregs[ 0x4F ],
       DSPregs[ 0x5F ],
       DSPregs[ 0x6F ],
       DSPregs[ 0x7F ]
       );
#endif

/* FIRptr is left in the position of the oldest sample, the one that will be
   replaced next update. */
outl += vl * ( signed char )DSPregs[ 0x2C ] >> 14;
outr += vr * ( signed char )DSPregs[ 0x3C ] >> 14;

if( !( DSPregs[ 0x6C ] & 0x20 ) )
    {
    /* Add the echo feedback back into the original result, and save that into
       memory for use later. */
    echol += vl * ( signed char )DSPregs[ 0x0D ] >> 14;
    if( echol > 32767 )
        {
        echol = 32767;
        }
    else if( echol < -32768 )
        {
        echol = -32768;
        }
    echor += vr * ( signed char )DSPregs[ 0x0D ] >> 14;
    if( echor > 32767 )
        {
        echor = 32767;
        }
    else if( echor < -32768 )
        {
        echor = -32768;
        }

#ifdef DBG_ECHO
    fprintf(
           stderr,
           "Echo: Writing %04X,%04X at location %04X\n",
           ( UINT16 )echol,
           ( UINT16 )echor,
           echo_base
           );
#endif

    *( UINT16 * )&spc_ram[ echo_base ]
        = MEtoLE16( ( UINT16 )echol );
    *( UINT16 * )&spc_ram[ echo_base + sizeof( short ) ]
        = MEtoLE16( ( UINT16 )echor );
    }

echo_ptr += 2 * sizeof( short );
if( echo_ptr >= ( ( DSPregs[ 0x7D ] & 0xF ) << 11 ) )
    {
    echo_ptr = 0;
    }
#endif                              /* !defined( NO_ECHO )          */

if( sound_ptr )
    {
    if( DSPregs[ 0x6C ] & 0x40 )
        {
        /* MUTE */
#ifdef DEBUG
        fprintf( stderr, "MUTED!\n" );
#endif

        *sound_ptr = 0;
        sound_ptr++;
        *sound_ptr = 0;
        sound_ptr++;
        }
    else
        {
        if( outl > 32767 )
            {
            *sound_ptr = 32767;
            }
        else if( outl < -32768 )
            {
            *sound_ptr = -32768;
            }
        else
            {
            *sound_ptr = outl;
            }
        sound_ptr++;
        if( outr > 32767 )
            {
            *sound_ptr = 32767;
            }
        else if( outr < -32768 )
            {
            *sound_ptr = -32768;
            }
        else
            {
            *sound_ptr = outr;
            }
        sound_ptr++;
        }
    }

}   /* DSP_Update() */


/***** AdvanceEnvelope *****/

static int AdvanceEnvelope          /* Run envelope step & retn ENVX*/
    (
    int                 v           /* Voice to process envelope for*/
    )
{
int                     envx;
int                     cnt;
int                     adsr1;
int                     t;

envx = voice_state[ v ].envx;

if( voice_state[ v ].envstate == RELEASE )
    {
    /* Docs: "When in the state of "key off". the "click" sound is prevented
       by the addition of the fixed value 1/256"  WTF???  Alright, I'm going
       to choose to interpret that this way:  When a note is keyed off, start
       the RELEASE state, which subtracts 1/256th each sample period (32kHz).
       Note there's no need for a count because it always happens every
       update. */
    envx -= 0x8;                    /* 0x8 / 0x800 = 1/256th        */
    if( envx <= 0 )
        {
        envx = 0;
        keys &= ~( 1 << v );
        return -1;
        }
    voice_state[ v ].envx = envx;
    DSPregs[ ( v << 4 ) + 8 ] = envx >> 8;

#ifdef DBG_ENV
    fprintf(
           stderr,
           "ENV voice %d: envx=%03X, state=RELEASE\n",
           v,
           envx
           );
#endif

    return( envx );
    }

cnt   = voice_state[ v ].envcnt;
adsr1 = DSPregs[ ( v << 4 ) + 5 ];
if( adsr1 & 0x80 )
    {
    switch( voice_state[ v ].envstate )
        {
        case ATTACK:
            /* Docs are very confusing.  "AR is multiplied by the fixed value
               1/64..."  I believe it means to add 1/64th to ENVX once every
               time ATTACK is updated, and that's what I'm going to implement.
               */
            t = adsr1 & 0xF;
            if( t == 0xF )
                {
#ifdef DBG_ENV
                fprintf( stderr, "ENV voice %d: instant attack\n", v );
#endif

                envx += 0x400;
                }
            else
                {
                cnt -= ENVCNT[ ( t << 1 ) + 1 ];
                if( cnt > 0 )
                    {
                    break;
                    }
                envx += 0x20;       /* 0x020 / 0x800 = 1/64         */
                cnt   = CNT_INIT;
                }

            if( envx > 0x7FF )
                {
                envx = 0x7FF;
                voice_state[ v ].envstate = DECAY;
                }

#ifdef DBG_ENV
            fprintf(
                   stderr,
                   "ENV voice %d: envx=%03X, state=ATTACK\n",
                   v,
                   envx
                   );
#endif

            voice_state[ v ].envx = envx;

            break;

        case DECAY:
            /* Docs: "DR... [is multiplied] by the fixed value 1-1/256."
               Well, at least that makes some sense.  Multiplying ENVX by
               255/256 every time DECAY is updated. */
            cnt -= ENVCNT[ ( ( adsr1 >> 3 ) & 0xE ) + 0x10 ];
            if( cnt <= 0 )
                {
                cnt   = CNT_INIT;
                envx -= ( ( envx - 1 ) >> 8 ) + 1;
                voice_state[ v ].envx = envx;
                }

            if( envx <= 0x100 * ( SL( v ) + 1 ) )
                {
                voice_state[ v ].envstate = SUSTAIN;
                }

#ifdef DBG_ENV
            fprintf(
                   stderr,
                   "ENV voice %d: envx=%03X, state=DECAY\n",
                   v,
                   envx
                   );
#endif

            break;

        case SUSTAIN:
            /* Docs: "SR [is multiplied] by the fixed value 1-1/256."
               Multiplying ENVX by 255/256 every time SUSTAIN is updated. */
#ifdef DBG_ENV
            if( ENVCNT[ SR( v ) ] == 0 )
                {
                fprintf(
                       stderr,
                       "ENV voice %d: envx=%03X, state=SUSTAIN, zero rate\n",
                       v,
                       envx
                       );
                }
#endif

            cnt -= ENVCNT[ SR( v ) ];
            if( cnt > 0 )
                {
                break;
                }
            cnt   = CNT_INIT;
            envx -= ( ( envx - 1 ) >> 8 ) + 1;

#ifdef DBG_ENV
            fprintf(
                   stderr,
                   "ENV voice %d: envx=%03X, state=SUSTAIN\n",
                   v,
                   envx
                   );
#endif

            voice_state[ v ].envx = envx;

            /* Note: no way out of this state except by explicit KEY OFF (or
               switch to GAIN). */
            break;

        case RELEASE:   /* Handled earlier to prevent GAIN mode from stopping
                           KEY OFF events */
            break;
        }
    }
else
    {
    /* GAIN mode is set
       Note: if the game switches between ADSR and GAIN modes partway
       through, should the count be reset, or should it continue from
       where it was?  Does the DSP actually watch for that bit to
       change, or does it just go along with whatever it sees when it
       performs the update?  I'm going to assume the latter and not
       update the count, unless I see a game that obviously wants the
       other behavior.  The effect would be pretty subtle, in any case.
       */
    t = DSPregs[ ( v << 4 ) + 7 ];
    if( t < 0x80 )
        {
        envx                  = t << 4;
        voice_state[ v ].envx = envx;

#ifdef DBG_ENV
        fprintf(
               stderr,
               "ENV voice %d: envx=%03X, state=DIRECT\n",
               v,
               envx
               );
#endif
        }
    else
        {
        switch( t >> 5 )
            {
            case 4:
                /* Docs: "Decrease (linear): Subtraction of the fixed value
                   1/64." */
                cnt -= ENVCNT[ t & 0x1F ];
                if( cnt > 0 )
                    {
                    break;
                    }
                cnt   = CNT_INIT;
                envx -= 0x020;      /* 0x020 / 0x800 = 1/64th       */
                if( envx < 0 )
                    {
                    envx = 0;
                    }

#ifdef DBG_ENV
                fprintf(
                       stderr,
                       "ENV voice %d: envx=%03X, state=DECREASE\n",
                       v,
                       envx
                       );
#endif

                voice_state[ v ].envx = envx;

                break;

            case 5:
                /* Docs: "Drecrease <sic> (exponential): Multiplication by
                   the fixed value 1-1/256." */
                cnt -= ENVCNT[ t & 0x1F ];
                if( cnt > 0 )
                    {
                    break;
                    }
                cnt = CNT_INIT;
                envx -= ( ( envx - 1 ) >> 8 ) + 1;

#ifdef DBG_ENV
                fprintf(
                       stderr,
                       "ENV voice %d: envx=%03X, state=EXP\n",
                       v,
                       envx
                       );
#endif

                voice_state[ v ].envx = envx;

                break;

            case 6:
                /* Docs: "Increase (linear): Addition of the fixed value
                   1/64." */
                cnt -= ENVCNT[ t & 0x1F ];
                if( cnt > 0 )
                {
                    break;
                }
                cnt = CNT_INIT;
                envx += 0x020;      /* 0x020 / 0x800 = 1/64th   */
                if( envx > 0x7FF )
                {
                    envx = 0x7FF;
                }

#ifdef DBG_ENV
                fprintf(
                       stderr,
                       "ENV voice %d: envx=%03X, state=INCREASE\n",
                       v,
                       envx
                       );
#endif

                voice_state[ v ].envx = envx;

                break;

            case 7:
                /* Docs: "Increase (bent line): Addition of the constant
                   1/64 up to .75 of the constaint <sic> 1/256 from .75 to
                   1." */
                cnt -= ENVCNT[ t & 0x1F ];
                if( cnt > 0 )
                    {
                    break;
                    }
                cnt = CNT_INIT;
                if( envx < 0x600 )  /* 0x600 / 0x800 = .75          */
                    {
                    envx += 0x020;  /* 0x020 / 0x800 = 1/64         */
                    }
                else
                    {
                    envx += 0x008;  /* 0x008 / 0x800 = 1/256        */
                    }
                if( envx > 0x7FF )
                    {
                    envx=0x7FF;
                    }

#ifdef DBG_ENV
                fprintf(
                       stderr,
                       "ENV voice %d: envx=%03X, state=INCREASE\n",
                       v,
                       envx
                       );
#endif

                voice_state[ v ].envx = envx;

                break;
            }
        }
    }

voice_state[ v ].envcnt   = cnt;
DSPregs[ ( v << 4 ) + 8 ] = envx >> 4;

return( envx );

}    /* AdvanceEnvelope() */

static TIMER_CALLBACK( snes_spc_timer  )
{
	int which = param;

	timers[which].counter++;
	if( timers[which].counter >= spc_ram[0xfa + which] ) // minus =
	{
		timers[which].counter = 0;
		spc_ram[0xfd + which]++;
		spc_ram[0xfd + which]&= 0xf;
	}
}

static DEVICE_START( snes_sound )
{
	running_machine *machine = device->machine;
	UINT8 ii;

	/* put IPL image at the top of RAM */
	memcpy(snes_ipl_region, memory_region(machine, "user5"), 64);

	/* default to ROM visible */
	spc_ram[0xf1] = 0x80;

	/* Sort out the ports */
	for( ii = 0; ii < 4; ii++ )
	{
		spc_port_in[ii] = 0;
		spc_port_out[ii] = 0;
	}

	channel = stream_create( device, 0, 2, 32000, NULL, snes_sh_update );

	/* Initialize the timers */
	timers[0].timer = timer_alloc(machine, snes_spc_timer , NULL);
	timer_adjust_periodic( timers[0].timer, ATTOTIME_IN_HZ(8000), 0, ATTOTIME_IN_HZ(8000) );
	timer_enable( timers[0].timer, 0 );
	timers[1].timer = timer_alloc(machine, snes_spc_timer , NULL);
	timer_adjust_periodic( timers[1].timer, ATTOTIME_IN_HZ(8000), 1, ATTOTIME_IN_HZ(8000) );
	timer_enable( timers[1].timer, 0 );
	timers[2].timer = timer_alloc(machine, snes_spc_timer , NULL);
	timer_adjust_periodic( timers[2].timer, ATTOTIME_IN_HZ(64000), 2, ATTOTIME_IN_HZ(64000) );
	timer_enable( timers[2].timer, 0 );

	DSP_Reset();
}

DEVICE_GET_INFO( snes_sound )
{
	switch (state)
	{
		/* --- the following bits of info are returned as pointers to data or functions --- */
		case DEVINFO_FCT_START:							info->start = DEVICE_START_NAME(snes_sound);	break;

		/* --- the following bits of info are returned as NULL-terminated strings --- */
		case DEVINFO_STR_NAME:							strcpy(info->s, "SNES Custom");					break;
		case DEVINFO_STR_SOURCE_FILE:						strcpy(info->s, __FILE__);						break;
	}
}


static STREAM_UPDATE( snes_sh_update )
{
	int i;
	short mix[2];

	for (i = 0; i < samples; i++)
	{
		mix[0] = mix[1] = 0;
		DSP_Update(mix);

		/* Update the buffers */
		outputs[0][i] = (stream_sample_t)mix[0];
		outputs[1][i] = (stream_sample_t)mix[1];
	}
}

/***************************
 *       I/O for DSP       *
 ***************************/

static READ8_HANDLER( snes_dsp_io_r )
{
	stream_update(channel);

#ifdef NO_ENVX
	if( 8 == ( SPCRAM[ 0xF2 ] & 0xF ) )
	{
		DSPregs[ SPCRAM[ 0xF2 ] ] = 0;
	}
#endif

	return DSPregs[offset & 0x7f];
}

static WRITE8_HANDLER( snes_dsp_io_w )
{
	stream_update(channel);

	if( 0x7C == offset )
	{
		DSP_WRITE_7C(data);
	}
	else
	{
		DSPregs[ offset ] = data;
	}
}

/***************************
 *     I/O for SPC700      *
 ***************************/
READ8_HANDLER( spc_io_r )
{
	switch( offset )	/* Offset is from 0x00f0 */
	{
		case 0x0: //FIXME: Super Bomberman PBW reads from there, is it really write-only?
			return 0;
		case 0x1:
			return 0; //Super Kick Boxing reads port 1 and wants it to be zero.
		case 0x2:		/* Register address */
			return spc_ram[0xf2];
		case 0x3:		/* Register data */
			return snes_dsp_io_r( space, spc_ram[0xf2] );
		case 0x4:		/* Port 0 */
		case 0x5:		/* Port 1 */
		case 0x6:		/* Port 2 */
		case 0x7:		/* Port 3 */
//          mame_printf_debug("SPC: rd %02x @ %d, PC=%x\n", spc_port_in[offset-4], offset-4, cpu_get_pc(space->cpu));
			return spc_port_in[offset - 4];
		case 0x8: //normal RAM, can be read even if the ram disabled flag ($f0 bit 1) is active
		case 0x9:
			return spc_ram[0xf0 + offset];
		case 0xA:		/* Timer 0 */
		case 0xB:		/* Timer 1 */
		case 0xC:		/* Timer 2 */
			break;
		case 0xD:		/* Counter 0 */
		case 0xE:		/* Counter 1 */
		case 0xF:		/* Counter 2 */
		{
			UINT8 value = spc_ram[0xf0 + offset] & 0xf;
			spc_ram[0xf0 + offset] = 0;
			return value;
		}
	}

	return 0;
}

WRITE8_HANDLER( spc_io_w )
{
	switch( offset )	/* Offset is from 0x00f0 */
	{
		case 0x0:
			printf("Warning: write to SOUND TEST register with data %02x!\n",data);
			break;
		case 0x1:		/* Control */
			if( data & 0x1 && !timers[0].enabled )
			{
				timers[0].counter = 0;
				spc_ram[0xfd] = 0;
			}
			if( data & 0x2 && !timers[1].enabled )
			{
				timers[1].counter = 0;
				spc_ram[0xfe] = 0;
			}
			if( data & 0x4 && !timers[2].enabled )
			{
				timers[2].counter = 0;
				spc_ram[0xff] = 0;
			}
			timers[0].enabled = data & 0x1;
			timer_enable( timers[0].timer, timers[0].enabled );
			timers[1].enabled = (data & 0x2) >> 1;
			timer_enable( timers[1].timer, timers[1].enabled );
			timers[2].enabled = (data & 0x4) >> 2;
			timer_enable( timers[2].timer, timers[2].enabled );
			if( data & 0x10 )
			{
				spc_port_in[0] = 0;
				spc_port_in[1] = 0;
			}
			if( data & 0x20 )
			{
				spc_port_in[2] = 0;
				spc_port_in[3] = 0;
			}

			if ((data & 0x80) != (spc_ram[0xf1] & 0x80))
			{
				if (data & 0x80)
				{
					memcpy(snes_ipl_region, memory_region(space->machine, "user5"), 64);
				}
				else
				{
					memcpy(snes_ipl_region, &spc_ram[0xffc0], 64);
				}
			}
			break;
		case 0x2:		/* Register address */
			break;
		case 0x3:		/* Register data */
			snes_dsp_io_w( space, spc_ram[0xf2], data );
			break;
		case 0x4:		/* Port 0 */
		case 0x5:		/* Port 1 */
		case 0x6:		/* Port 2 */
		case 0x7:		/* Port 3 */
//          mame_printf_debug("SPC: %02x to APU @ %d (PC=%x)\n", data, offset&3, cpu_get_pc(space->cpu));
			spc_port_out[offset - 4] = data;
			cpuexec_boost_interleave(space->machine, attotime_zero, ATTOTIME_IN_USEC(20));
			break;
		case 0xA:		/* Timer 0 */
		case 0xB:		/* Timer 1 */
		case 0xC:		/* Timer 2 */
			if (data == 0) data = 255;
			break;
		case 0xD:		/* Counter 0 */
		case 0xE:		/* Counter 1 */
		case 0xF:		/* Counter 2 */
			return;
	}

	spc_ram[0xf0 + offset] = data;
}

READ8_HANDLER( spc_ram_r )
{
	return spc_ram[offset];
}

WRITE8_HANDLER( spc_ram_w )
{
	spc_ram[offset] = data;

	// if RAM is mapped in, mirror accordingly
	if ((!(spc_ram[0xf1] & 0x80)) && (offset >= 0xffc0))
	{
		snes_ipl_region[offset-0xffc0] = data;
	}
}

READ8_HANDLER( spc_ipl_r )
{
	return snes_ipl_region[offset];
}