summaryrefslogtreecommitdiffstatshomepage
path: root/src/lib/util/cdrom.c
blob: 5974373803e578117270c18cc42f985208b61431 (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
/***************************************************************************

    cdrom.c

    Generic MAME CD-ROM utilties - build IDE and SCSI CD-ROMs on top of this

****************************************************************************

    Copyright Aaron Giles
    All rights reserved.

    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions are
    met:

        * Redistributions of source code must retain the above copyright
          notice, this list of conditions and the following disclaimer.
        * Redistributions in binary form must reproduce the above copyright
          notice, this list of conditions and the following disclaimer in
          the documentation and/or other materials provided with the
          distribution.
        * Neither the name 'MAME' nor the names of its contributors may be
          used to endorse or promote products derived from this software
          without specific prior written permission.

    THIS SOFTWARE IS PROVIDED BY AARON GILES ''AS IS'' AND ANY EXPRESS OR
    IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
    WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
    DISCLAIMED. IN NO EVENT SHALL AARON GILES BE LIABLE FOR ANY DIRECT,
    INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
    (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
    SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
    HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
    STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
    IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
    POSSIBILITY OF SUCH DAMAGE.

****************************************************************************

    IMPORTANT:
    "physical" block addresses are the actual addresses on the emulated CD.
    "chd" block addresses are the block addresses in the CHD file.
    Because we pad each track to a 4-frame boundry, these addressing
    schemes will differ after track 1!

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

#include "cdrom.h"

#include <stdlib.h>
#include "chdcd.h"


/***************************************************************************
    DEBUGGING
***************************************************************************/

#define VERBOSE	(0)
#if VERBOSE
#define LOG(x) do { if (VERBOSE) logerror x; } while (0)
void CLIB_DECL logerror(const char *text,...);
#else
#define LOG(x)
#endif



/***************************************************************************
    CONSTANTS
***************************************************************************/

const int SYNC_OFFSET = 0x000;		// offset within sector
const int SYNC_NUM_BYTES = 12;		// 12 bytes

const int MODE_OFFSET = 0x00f;		// offset within sector 

const int ECC_P_OFFSET = 0x81c;		// offset within sector
const int ECC_P_NUM_BYTES = 86;		// 2 lots of 86
const int ECC_P_COMP = 24;			// 24 bytes each

const int ECC_Q_OFFSET = ECC_P_OFFSET + 2 * ECC_P_NUM_BYTES;
const int ECC_Q_NUM_BYTES = 52;		// 2 lots of 52
const int ECC_Q_COMP = 43;			// 43 bytes each



/***************************************************************************
    TYPE DEFINITIONS
***************************************************************************/

struct _cdrom_file
{
	chd_file *			chd;				/* CHD file */
	cdrom_toc			cdtoc;				/* TOC for the CD */
	chdcd_track_input_info track_info;		/* track info */
	core_file *			fhandle[CD_MAX_TRACKS];/* file handle */
};



/***************************************************************************
    INLINE FUNCTIONS
***************************************************************************/

/*-------------------------------------------------
    physical_to_chd_lba - find the CHD LBA
    and the track number
-------------------------------------------------*/

INLINE UINT32 physical_to_chd_lba(cdrom_file *file, UINT32 physlba, UINT32 &tracknum)
{
	UINT32 chdlba;
	int track;

	/* loop until our current LBA is less than the start LBA of the next track */
	for (track = 0; track < file->cdtoc.numtrks; track++)
		if (physlba < file->cdtoc.tracks[track + 1].physframeofs)
		{
			chdlba = physlba - file->cdtoc.tracks[track].physframeofs + file->cdtoc.tracks[track].chdframeofs;
			tracknum = track;
			return chdlba;
		}

	return physlba;
}



/***************************************************************************
    BASE FUNCTIONALITY
***************************************************************************/

cdrom_file *cdrom_open(const char *inputfile)
{
	int i;
	cdrom_file *file;
	UINT32 physofs;

	/* allocate memory for the CD-ROM file */
	file = new cdrom_file();
	if (file == NULL)
		return NULL;

	/* setup the CDROM module and get the disc info */
	chd_error err = chdcd_parse_toc(inputfile, file->cdtoc, file->track_info);
	if (err != CHDERR_NONE)
	{
		fprintf(stderr, "Error reading input file: %s\n", chd_file::error_string(err));
		return NULL;
	}

	/* fill in the data */
	file->chd = NULL;

	LOG(("CD has %d tracks\n", file->cdtoc.numtrks));

	for (i = 0; i < file->cdtoc.numtrks; i++)
	{
		file_error filerr = core_fopen(file->track_info.track[i].fname, OPEN_FLAG_READ, &file->fhandle[i]);
		if (filerr != FILERR_NONE)
		{
			fprintf(stderr, "Unable to open file: %s\n", file->track_info.track[i].fname.cstr());
			return NULL;
		}
	}
	/* calculate the starting frame for each track, keeping in mind that CHDMAN
       pads tracks out with extra frames to fit 4-frame size boundries
    */
	physofs = 0;
	for (i = 0; i < file->cdtoc.numtrks; i++)
	{
		file->cdtoc.tracks[i].physframeofs = physofs;
		file->cdtoc.tracks[i].chdframeofs = 0;

		physofs += file->cdtoc.tracks[i].frames;

		LOG(("Track %02d is format %d subtype %d datasize %d subsize %d frames %d extraframes %d physofs %d chdofs %d\n", i+1,
			file->cdtoc.tracks[i].trktype,
			file->cdtoc.tracks[i].subtype,
			file->cdtoc.tracks[i].datasize,
			file->cdtoc.tracks[i].subsize,
			file->cdtoc.tracks[i].frames,
			file->cdtoc.tracks[i].extraframes,
			file->cdtoc.tracks[i].physframeofs,
			file->cdtoc.tracks[i].chdframeofs));
	}

	/* fill out dummy entries for the last track to help our search */
	file->cdtoc.tracks[i].physframeofs = physofs;
	file->cdtoc.tracks[i].chdframeofs = 0;

	return file;
}

/*-------------------------------------------------
    cdrom_open - "open" a CD-ROM file from an
    already-opened CHD file
-------------------------------------------------*/

cdrom_file *cdrom_open(chd_file *chd)
{
	int i;
	cdrom_file *file;
	UINT32 physofs, chdofs;
	chd_error err;

	/* punt if no CHD */
	if (!chd)
		return NULL;

	/* validate the CHD information */
	if (chd->hunk_bytes() % CD_FRAME_SIZE != 0)
		return NULL;
	if (chd->unit_bytes() != CD_FRAME_SIZE)
		return NULL;

	/* allocate memory for the CD-ROM file */
	file = (cdrom_file *)malloc(sizeof(cdrom_file));
	if (file == NULL)
		return NULL;

	/* fill in the data */
	file->chd = chd;

	/* read the CD-ROM metadata */
	err = cdrom_parse_metadata(chd, &file->cdtoc);
	if (err != CHDERR_NONE)
	{
		delete(file);
		return NULL;
	}

	LOG(("CD has %d tracks\n", file->cdtoc.numtrks));

	/* calculate the starting frame for each track, keeping in mind that CHDMAN
       pads tracks out with extra frames to fit 4-frame size boundries
    */
	physofs = chdofs = 0;
	for (i = 0; i < file->cdtoc.numtrks; i++)
	{
		file->cdtoc.tracks[i].physframeofs = physofs;
		file->cdtoc.tracks[i].chdframeofs = chdofs;

		physofs += file->cdtoc.tracks[i].frames;
		chdofs  += file->cdtoc.tracks[i].frames;
		chdofs  += file->cdtoc.tracks[i].extraframes;

		LOG(("Track %02d is format %d subtype %d datasize %d subsize %d frames %d extraframes %d physofs %d chdofs %d\n", i+1,
			file->cdtoc.tracks[i].trktype,
			file->cdtoc.tracks[i].subtype,
			file->cdtoc.tracks[i].datasize,
			file->cdtoc.tracks[i].subsize,
			file->cdtoc.tracks[i].frames,
			file->cdtoc.tracks[i].extraframes,
			file->cdtoc.tracks[i].physframeofs,
			file->cdtoc.tracks[i].chdframeofs));
	}

	/* fill out dummy entries for the last track to help our search */
	file->cdtoc.tracks[i].physframeofs = physofs;
	file->cdtoc.tracks[i].chdframeofs = chdofs;

	return file;
}


/*-------------------------------------------------
    cdrom_close - "close" a CD-ROM file
-------------------------------------------------*/

void cdrom_close(cdrom_file *file)
{
	if (file == NULL)
		return;

	if (file->chd == NULL)
	{
		for (int i = 0; i < file->cdtoc.numtrks; i++)
		{
			core_fclose(file->fhandle[i]);
		}
	}

	delete(file);
}



/***************************************************************************
    CORE READ ACCESS
***************************************************************************/

chd_error read_partial_sector(cdrom_file *file, void *dest, UINT32 chdsector, UINT32 tracknum, UINT32 startoffs, UINT32 length)
{
	// if a CHD, just read
	if (file->chd != NULL)
		return file->chd->read_bytes(UINT64(chdsector) * UINT64(CD_FRAME_SIZE) + startoffs, dest, length);

	// else read from the appropriate file
	core_file *srcfile = file->fhandle[tracknum];

	UINT64 sourcefileoffset = file->track_info.track[tracknum].offset;
	int bytespersector = file->cdtoc.tracks[tracknum].datasize + file->cdtoc.tracks[tracknum].subsize;

	sourcefileoffset += chdsector * bytespersector + startoffs;

	core_fseek(srcfile, sourcefileoffset, SEEK_SET);
	core_fread(srcfile, dest, length);

	if (file->track_info.track[tracknum].swap)
	{
		UINT8 *buffer = (UINT8 *)dest - startoffs;
		for (int swapindex = startoffs; swapindex < 2352; swapindex += 2 )
		{
			int swaptemp = buffer[ swapindex ];
			buffer[ swapindex ] = buffer[ swapindex + 1 ];
			buffer[ swapindex + 1 ] = swaptemp;
		}
	}
	return CHDERR_NONE;
}


/*-------------------------------------------------
    cdrom_read_data - read one or more sectors
    from a CD-ROM
-------------------------------------------------*/

UINT32 cdrom_read_data(cdrom_file *file, UINT32 lbasector, void *buffer, UINT32 datatype)
{
	if (file == NULL)
		return 0;

	// compute CHD sector and tracknumber
	UINT32 tracknum = 0;
	UINT32 chdsector = physical_to_chd_lba(file, lbasector, tracknum);

	/* copy out the requested sector */
	UINT32 tracktype = file->cdtoc.tracks[tracknum].trktype;
	if ((datatype == tracktype) || (datatype == CD_TRACK_RAW_DONTCARE))
	{
		return (read_partial_sector(file, buffer, chdsector, tracknum, 0, file->cdtoc.tracks[tracknum].datasize) == CHDERR_NONE);
	}
	else
	{
		/* return 2048 bytes of mode 1 data from a 2352 byte mode 1 raw sector */
		if ((datatype == CD_TRACK_MODE1) && (tracktype == CD_TRACK_MODE1_RAW))
		{
			return (read_partial_sector(file, buffer, chdsector, tracknum, 16, 2048) == CHDERR_NONE);
		}

		/* return 2352 byte mode 1 raw sector from 2048 bytes of mode 1 data */
		if ((datatype == CD_TRACK_MODE1_RAW) && (tracktype == CD_TRACK_MODE1))
		{
			UINT8 *bufptr = (UINT8 *)buffer;
			UINT32 msf = lba_to_msf(lbasector);

			static const UINT8 syncbytes[12] = {0x00, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00};
			memcpy(bufptr, syncbytes, 12);
			bufptr[12] = msf>>16;
			bufptr[13] = msf>>8;
			bufptr[14] = msf&0xff;
			bufptr[15] = 1;	// mode 1
			LOG(("CDROM: promotion of mode1/form1 sector to mode1 raw is not complete!\n"));
			return (read_partial_sector(file, bufptr+16, chdsector, tracknum, 0, 2048) == CHDERR_NONE);
		}

		/* return 2048 bytes of mode 1 data from a mode2 form1 or raw sector */
		if ((datatype == CD_TRACK_MODE1) && ((tracktype == CD_TRACK_MODE2_FORM1)||(tracktype == CD_TRACK_MODE2_RAW)))
		{
			return (read_partial_sector(file, buffer, chdsector, tracknum, 24, 2048) == CHDERR_NONE);
		}

		/* return mode 2 2336 byte data from a 2352 byte mode 1 or 2 raw sector (skip the header) */
		if ((datatype == CD_TRACK_MODE2) && ((tracktype == CD_TRACK_MODE1_RAW) || (tracktype == CD_TRACK_MODE2_RAW)))
		{
			return (read_partial_sector(file, buffer, chdsector, tracknum, 16, 2336) == CHDERR_NONE);
		}

		LOG(("CDROM: Conversion from type %d to type %d not supported!\n", tracktype, datatype));
		return 0;
	}
}


/*-------------------------------------------------
    cdrom_read_subcode - read subcode data for
    a sector
-------------------------------------------------*/

UINT32 cdrom_read_subcode(cdrom_file *file, UINT32 lbasector, void *buffer)
{
	if (file == NULL)
		return ~0;

	// compute CHD sector and tracknumber
	UINT32 tracknum = 0;
	UINT32 chdsector = physical_to_chd_lba(file, lbasector, tracknum);
	if (file->cdtoc.tracks[tracknum].subsize == 0)
		return 1;

	// read the data
	chd_error err = read_partial_sector(file, buffer, chdsector, tracknum, file->cdtoc.tracks[tracknum].datasize, file->cdtoc.tracks[tracknum].subsize);
	return (err == CHDERR_NONE);
}



/***************************************************************************
    HANDY UTILITIES
***************************************************************************/

/*-------------------------------------------------
    cdrom_get_track - get the track number
    for a physical frame number
-------------------------------------------------*/

UINT32 cdrom_get_track(cdrom_file *file, UINT32 frame)
{
	UINT32 track = 0;

	if (file == NULL)
		return ~0;

	/* convert to a CHD sector offset and get track information */
	physical_to_chd_lba(file, frame, track);
	return track;
}


/*-------------------------------------------------
    cdrom_get_track_start - get the frame number
    that a track starts at
-------------------------------------------------*/

UINT32 cdrom_get_track_start(cdrom_file *file, UINT32 track)
{
	if (file == NULL)
		return ~0;

	/* handle lead-out specially */
	if (track == 0xaa)
		track = file->cdtoc.numtrks;

	return file->cdtoc.tracks[track].physframeofs;
}



/***************************************************************************
    TOC UTILITIES
***************************************************************************/

/*-------------------------------------------------
    cdrom_get_last_track - returns the last track
    number
-------------------------------------------------*/

int cdrom_get_last_track(cdrom_file *file)
{
	if (file == NULL)
		return -1;

	return file->cdtoc.numtrks;
}


/*-------------------------------------------------
    cdrom_get_adr_control - get the ADR | CONTROL
    for a track
-------------------------------------------------*/

int cdrom_get_adr_control(cdrom_file *file, int track)
{
	if (file == NULL)
		return -1;

	if (track == 0xaa || file->cdtoc.tracks[track].trktype == CD_TRACK_AUDIO)
	{
		return 0x10;	// audio track, subchannel is position
	}

	return 0x14;	// data track, subchannel is position
}


/*-------------------------------------------------
    cdrom_get_track_type - return the track type
-------------------------------------------------*/

int cdrom_get_track_type(cdrom_file *file, int track)
{
	if (file == NULL)
		return -1;

	return file->cdtoc.tracks[track].trktype;
}


/*-------------------------------------------------
    cdrom_get_toc - return the TOC data for a
    CD-ROM
-------------------------------------------------*/

const cdrom_toc *cdrom_get_toc(cdrom_file *file)
{
	if (file == NULL)
		return NULL;

	return &file->cdtoc;
}



/***************************************************************************
    EXTRA UTILITIES
***************************************************************************/

/*-------------------------------------------------
    cdrom_get_info_from_type_string
    take a string and convert it into track type
    and track data size
-------------------------------------------------*/

static void cdrom_get_info_from_type_string(const char *typestring, UINT32 *trktype, UINT32 *datasize)
{
	if (!strcmp(typestring, "MODE1"))
	{
		*trktype = CD_TRACK_MODE1;
		*datasize = 2048;
	}
	else if (!strcmp(typestring, "MODE1/2048"))
	{
		*trktype = CD_TRACK_MODE1;
		*datasize = 2048;
	}
	else if (!strcmp(typestring, "MODE1_RAW"))
	{
		*trktype = CD_TRACK_MODE1_RAW;
		*datasize = 2352;
	}
	else if (!strcmp(typestring, "MODE1/2352"))
	{
		*trktype = CD_TRACK_MODE1_RAW;
		*datasize = 2352;
	}
	else if (!strcmp(typestring, "MODE2"))
	{
		*trktype = CD_TRACK_MODE2;
		*datasize = 2336;
	}
	else if (!strcmp(typestring, "MODE2/2336"))
	{
		*trktype = CD_TRACK_MODE2;
		*datasize = 2336;
	}
	else if (!strcmp(typestring, "MODE2_FORM1"))
	{
		*trktype = CD_TRACK_MODE2_FORM1;
		*datasize = 2048;
	}
	else if (!strcmp(typestring, "MODE2/2048"))
	{
		*trktype = CD_TRACK_MODE2_FORM1;
		*datasize = 2048;
	}
	else if (!strcmp(typestring, "MODE2_FORM2"))
	{
		*trktype = CD_TRACK_MODE2_FORM2;
		*datasize = 2324;
	}
	else if (!strcmp(typestring, "MODE2/2324"))
	{
		*trktype = CD_TRACK_MODE2_FORM2;
		*datasize = 2324;
	}
	else if (!strcmp(typestring, "MODE2_FORM_MIX"))
	{
		*trktype = CD_TRACK_MODE2_FORM_MIX;
		*datasize = 2336;
	}
	else if (!strcmp(typestring, "MODE2/2336"))
	{
		*trktype = CD_TRACK_MODE2_FORM_MIX;
		*datasize = 2336;
	}
	else if (!strcmp(typestring, "MODE2_RAW"))
	{
		*trktype = CD_TRACK_MODE2_RAW;
		*datasize = 2352;
	}
	else if (!strcmp(typestring, "MODE2/2352"))
	{
		*trktype = CD_TRACK_MODE2_RAW;
		*datasize = 2352;
	}
	else if (!strcmp(typestring, "AUDIO"))
	{
		*trktype = CD_TRACK_AUDIO;
		*datasize = 2352;
	}
}

/*-------------------------------------------------
    cdrom_convert_type_string_to_track_info -
    take a string and convert it into track type
    and track data size
-------------------------------------------------*/

void cdrom_convert_type_string_to_track_info(const char *typestring, cdrom_track_info *info)
{
	cdrom_get_info_from_type_string(typestring, &info->trktype, &info->datasize);
}

/*-------------------------------------------------
    cdrom_convert_type_string_to_pregap_info -
    take a string and convert it into pregap type
    and pregap data size
-------------------------------------------------*/

void cdrom_convert_type_string_to_pregap_info(const char *typestring, cdrom_track_info *info)
{
	cdrom_get_info_from_type_string(typestring, &info->pgtype, &info->pgdatasize);
}

/*-------------------------------------------------
    cdrom_convert_subtype_string_to_track_info -
    take a string and convert it into track subtype
    and track subcode data size
-------------------------------------------------*/

void cdrom_convert_subtype_string_to_track_info(const char *typestring, cdrom_track_info *info)
{
	if (!strcmp(typestring, "RW"))
	{
		info->subtype = CD_SUB_NORMAL;
		info->subsize = 96;
	}
	else if (!strcmp(typestring, "RW_RAW"))
	{
		info->subtype = CD_SUB_RAW;
		info->subsize = 96;
	}
}

/*-------------------------------------------------
    cdrom_convert_subtype_string_to_pregap_info -
    take a string and convert it into track subtype
    and track subcode data size
-------------------------------------------------*/

void cdrom_convert_subtype_string_to_pregap_info(const char *typestring, cdrom_track_info *info)
{
	if (!strcmp(typestring, "RW"))
	{
		info->pgsub = CD_SUB_NORMAL;
		info->pgsubsize = 96;
	}
	else if (!strcmp(typestring, "RW_RAW"))
	{
		info->pgsub = CD_SUB_RAW;
		info->pgsubsize = 96;
	}
}

/*-------------------------------------------------
    cdrom_get_type_string - get the string
    associated with the given type
-------------------------------------------------*/

const char *cdrom_get_type_string(UINT32 trktype)
{
	switch (trktype)
	{
		case CD_TRACK_MODE1:			return "MODE1";
		case CD_TRACK_MODE1_RAW:		return "MODE1_RAW";
		case CD_TRACK_MODE2:			return "MODE2";
		case CD_TRACK_MODE2_FORM1:		return "MODE2_FORM1";
		case CD_TRACK_MODE2_FORM2:		return "MODE2_FORM2";
		case CD_TRACK_MODE2_FORM_MIX:	return "MODE2_FORM_MIX";
		case CD_TRACK_MODE2_RAW:		return "MODE2_RAW";
		case CD_TRACK_AUDIO:			return "AUDIO";
		default:						return "UNKNOWN";
	}
}


/*-------------------------------------------------
    cdrom_get_subtype_string - get the string
    associated with the given subcode type
-------------------------------------------------*/

const char *cdrom_get_subtype_string(UINT32 subtype)
{
	switch (subtype)
	{
		case CD_SUB_NORMAL:				return "RW";
		case CD_SUB_RAW:				return "RW_RAW";
		default:						return "NONE";
	}
}



/***************************************************************************
    INTERNAL UTILITIES
***************************************************************************/

/*-------------------------------------------------
    cdrom_parse_metadata - parse metadata into the
    TOC structure
-------------------------------------------------*/

chd_error cdrom_parse_metadata(chd_file *chd, cdrom_toc *toc)
{
	astring metadata;
	chd_error err;
	int i;

	/* start with no tracks */
	for (toc->numtrks = 0; toc->numtrks < CD_MAX_TRACKS; toc->numtrks++)
	{
		int tracknum = -1, frames = 0, pregap, postgap, padframes;
		char type[16], subtype[16], pgtype[16], pgsub[16];
		cdrom_track_info *track;

		pregap = postgap = padframes = 0;

		/* fetch the metadata for this track */
		err = chd->read_metadata(CDROM_TRACK_METADATA_TAG, toc->numtrks, metadata);
		if (err == CHDERR_NONE)
		{
			/* parse the metadata */
			type[0] = subtype[0] = 0;
			if (sscanf(metadata, CDROM_TRACK_METADATA_FORMAT, &tracknum, type, subtype, &frames) != 4)
				return CHDERR_INVALID_DATA;
			if (tracknum == 0 || tracknum > CD_MAX_TRACKS)
				return CHDERR_INVALID_DATA;
			track = &toc->tracks[tracknum - 1];
		}
		else
		{
			err = chd->read_metadata(CDROM_TRACK_METADATA2_TAG, toc->numtrks, metadata);
			if (err == CHDERR_NONE)
            {
                /* parse the metadata */
                type[0] = subtype[0] = 0;
                pregap = postgap = 0;
                if (sscanf(metadata, CDROM_TRACK_METADATA2_FORMAT, &tracknum, type, subtype, &frames, &pregap, pgtype, pgsub, &postgap) != 8)
                    return CHDERR_INVALID_DATA;
                if (tracknum == 0 || tracknum > CD_MAX_TRACKS)
                    return CHDERR_INVALID_DATA;
                track = &toc->tracks[tracknum - 1];
            }
            else
            {
                err = chd->read_metadata(GDROM_TRACK_METADATA_TAG, toc->numtrks, metadata);

                if (err == CHDERR_NONE)
                {
                    /* parse the metadata */
                    type[0] = subtype[0] = 0;
                    pregap = postgap = 0;
                    if (sscanf(metadata, GDROM_TRACK_METADATA_FORMAT, &tracknum, type, subtype, &frames, &padframes, &pregap, pgtype, pgsub, &postgap) != 9)
                        return CHDERR_INVALID_DATA;
                    if (tracknum == 0 || tracknum > CD_MAX_TRACKS)
                        return CHDERR_INVALID_DATA;
                    track = &toc->tracks[tracknum - 1];
                }
                else
                {
                    break;
                }
            }
		}

		/* extract the track type and determine the data size */
		track->trktype = CD_TRACK_MODE1;
		track->datasize = 0;
		cdrom_convert_type_string_to_track_info(type, track);
		if (track->datasize == 0)
			return CHDERR_INVALID_DATA;

		/* extract the subtype and determine the subcode data size */
		track->subtype = CD_SUB_NONE;
		track->subsize = 0;
		cdrom_convert_subtype_string_to_track_info(subtype, track);

		/* set the frames and extra frames data */
		track->frames = frames;
        track->padframes = padframes;
		int padded = (frames + CD_TRACK_PADDING - 1) / CD_TRACK_PADDING;
		track->extraframes = padded * CD_TRACK_PADDING - frames;

		/* set the pregap info */
		track->pregap = pregap;
		track->pgtype = CD_TRACK_MODE1;
		track->pgsub = CD_SUB_NONE;
		track->pgdatasize = 0;
		track->pgsubsize = 0;
		cdrom_convert_type_string_to_pregap_info(pgtype, track);
		cdrom_convert_subtype_string_to_pregap_info(pgsub, track);

        /* set the postgap info */
        track->postgap = postgap;
	}

	/* if we got any tracks this way, we're done */
	if (toc->numtrks > 0)
		return CHDERR_NONE;

    printf("toc->numtrks = %d?!\n", toc->numtrks);

	/* look for old-style metadata */
	dynamic_buffer oldmetadata;
	err = chd->read_metadata(CDROM_OLD_METADATA_TAG, 0, oldmetadata);
	if (err != CHDERR_NONE)
		return err;

	/* reconstruct the TOC from it */
	UINT32 *mrp = reinterpret_cast<UINT32 *>(&oldmetadata[0]);
	toc->numtrks = *mrp++;

	for (i = 0; i < CD_MAX_TRACKS; i++)
	{
		toc->tracks[i].trktype = *mrp++;
		toc->tracks[i].subtype = *mrp++;
		toc->tracks[i].datasize = *mrp++;
		toc->tracks[i].subsize = *mrp++;
		toc->tracks[i].frames = *mrp++;
		toc->tracks[i].extraframes = *mrp++;
		toc->tracks[i].pregap = 0;
		toc->tracks[i].postgap = 0;
		toc->tracks[i].pgtype = 0;
		toc->tracks[i].pgsub = 0;
		toc->tracks[i].pgdatasize = 0;
		toc->tracks[i].pgsubsize = 0;
	}

	/* TODO: I don't know why sometimes the data is one endian and sometimes another */
	if ((toc->numtrks < 0) || (toc->numtrks > CD_MAX_TRACKS))
	{
		toc->numtrks = FLIPENDIAN_INT32(toc->numtrks);
		for (i = 0; i < CD_MAX_TRACKS; i++)
		{
			toc->tracks[i].trktype = FLIPENDIAN_INT32(toc->tracks[i].trktype);
			toc->tracks[i].subtype = FLIPENDIAN_INT32(toc->tracks[i].subtype);
			toc->tracks[i].datasize = FLIPENDIAN_INT32(toc->tracks[i].datasize);
			toc->tracks[i].subsize = FLIPENDIAN_INT32(toc->tracks[i].subsize);
			toc->tracks[i].frames = FLIPENDIAN_INT32(toc->tracks[i].frames);
			toc->tracks[i].padframes = FLIPENDIAN_INT32(toc->tracks[i].padframes);
			toc->tracks[i].extraframes = FLIPENDIAN_INT32(toc->tracks[i].extraframes);
		}
	}

	return CHDERR_NONE;
}


/*-------------------------------------------------
    cdrom_write_metadata - write metadata
-------------------------------------------------*/

chd_error cdrom_write_metadata(chd_file *chd, const cdrom_toc *toc)
{
	chd_error err;
	int i;

	/* write the metadata */
	for (i = 0; i < toc->numtrks; i++)
	{
        astring metadata;
        if (!(toc->flags & CD_FLAG_GDROM))
        {
            metadata.format(CDROM_TRACK_METADATA2_FORMAT, i + 1, cdrom_get_type_string(toc->tracks[i].trktype),
                    cdrom_get_subtype_string(toc->tracks[i].subtype), toc->tracks[i].frames, toc->tracks[i].pregap,
                    cdrom_get_type_string(toc->tracks[i].pgtype), cdrom_get_subtype_string(toc->tracks[i].pgsub),
                    toc->tracks[i].postgap);

            err = chd->write_metadata(CDROM_TRACK_METADATA2_TAG, i, metadata);
        }
        else
        {
            metadata.format(GDROM_TRACK_METADATA_FORMAT, i + 1, cdrom_get_type_string(toc->tracks[i].trktype),
                    cdrom_get_subtype_string(toc->tracks[i].subtype), toc->tracks[i].frames, toc->tracks[i].padframes,
                    toc->tracks[i].pregap, cdrom_get_type_string(toc->tracks[i].pgtype),
                    cdrom_get_subtype_string(toc->tracks[i].pgsub), toc->tracks[i].postgap);

            err = chd->write_metadata(GDROM_TRACK_METADATA_TAG, i, metadata);
        }
		if (err != CHDERR_NONE)
			return err;
	}
	return CHDERR_NONE;
}


//-------------------------------------------------
//  ECC lookup tables
//	pre-calculated tables for ECC data calcs
//-------------------------------------------------

static const UINT8 ecclow[256] =
{
	0x00, 0x02, 0x04, 0x06, 0x08, 0x0a, 0x0c, 0x0e, 0x10, 0x12, 0x14, 0x16, 0x18, 0x1a, 0x1c, 0x1e,
	0x20, 0x22, 0x24, 0x26, 0x28, 0x2a, 0x2c, 0x2e, 0x30, 0x32, 0x34, 0x36, 0x38, 0x3a, 0x3c, 0x3e,
	0x40, 0x42, 0x44, 0x46, 0x48, 0x4a, 0x4c, 0x4e, 0x50, 0x52, 0x54, 0x56, 0x58, 0x5a, 0x5c, 0x5e,
	0x60, 0x62, 0x64, 0x66, 0x68, 0x6a, 0x6c, 0x6e, 0x70, 0x72, 0x74, 0x76, 0x78, 0x7a, 0x7c, 0x7e,
	0x80, 0x82, 0x84, 0x86, 0x88, 0x8a, 0x8c, 0x8e, 0x90, 0x92, 0x94, 0x96, 0x98, 0x9a, 0x9c, 0x9e,
	0xa0, 0xa2, 0xa4, 0xa6, 0xa8, 0xaa, 0xac, 0xae, 0xb0, 0xb2, 0xb4, 0xb6, 0xb8, 0xba, 0xbc, 0xbe,
	0xc0, 0xc2, 0xc4, 0xc6, 0xc8, 0xca, 0xcc, 0xce, 0xd0, 0xd2, 0xd4, 0xd6, 0xd8, 0xda, 0xdc, 0xde,
	0xe0, 0xe2, 0xe4, 0xe6, 0xe8, 0xea, 0xec, 0xee, 0xf0, 0xf2, 0xf4, 0xf6, 0xf8, 0xfa, 0xfc, 0xfe,
	0x1d, 0x1f, 0x19, 0x1b, 0x15, 0x17, 0x11, 0x13, 0x0d, 0x0f, 0x09, 0x0b, 0x05, 0x07, 0x01, 0x03,
	0x3d, 0x3f, 0x39, 0x3b, 0x35, 0x37, 0x31, 0x33, 0x2d, 0x2f, 0x29, 0x2b, 0x25, 0x27, 0x21, 0x23,
	0x5d, 0x5f, 0x59, 0x5b, 0x55, 0x57, 0x51, 0x53, 0x4d, 0x4f, 0x49, 0x4b, 0x45, 0x47, 0x41, 0x43,
	0x7d, 0x7f, 0x79, 0x7b, 0x75, 0x77, 0x71, 0x73, 0x6d, 0x6f, 0x69, 0x6b, 0x65, 0x67, 0x61, 0x63,
	0x9d, 0x9f, 0x99, 0x9b, 0x95, 0x97, 0x91, 0x93, 0x8d, 0x8f, 0x89, 0x8b, 0x85, 0x87, 0x81, 0x83,
	0xbd, 0xbf, 0xb9, 0xbb, 0xb5, 0xb7, 0xb1, 0xb3, 0xad, 0xaf, 0xa9, 0xab, 0xa5, 0xa7, 0xa1, 0xa3,
	0xdd, 0xdf, 0xd9, 0xdb, 0xd5, 0xd7, 0xd1, 0xd3, 0xcd, 0xcf, 0xc9, 0xcb, 0xc5, 0xc7, 0xc1, 0xc3,
	0xfd, 0xff, 0xf9, 0xfb, 0xf5, 0xf7, 0xf1, 0xf3, 0xed, 0xef, 0xe9, 0xeb, 0xe5, 0xe7, 0xe1, 0xe3
};

static const UINT8 ecchigh[256] =
{
	0x00, 0xf4, 0xf5, 0x01, 0xf7, 0x03, 0x02, 0xf6, 0xf3, 0x07, 0x06, 0xf2, 0x04, 0xf0, 0xf1, 0x05,
	0xfb, 0x0f, 0x0e, 0xfa, 0x0c, 0xf8, 0xf9, 0x0d, 0x08, 0xfc, 0xfd, 0x09, 0xff, 0x0b, 0x0a, 0xfe,
	0xeb, 0x1f, 0x1e, 0xea, 0x1c, 0xe8, 0xe9, 0x1d, 0x18, 0xec, 0xed, 0x19, 0xef, 0x1b, 0x1a, 0xee,
	0x10, 0xe4, 0xe5, 0x11, 0xe7, 0x13, 0x12, 0xe6, 0xe3, 0x17, 0x16, 0xe2, 0x14, 0xe0, 0xe1, 0x15,
	0xcb, 0x3f, 0x3e, 0xca, 0x3c, 0xc8, 0xc9, 0x3d, 0x38, 0xcc, 0xcd, 0x39, 0xcf, 0x3b, 0x3a, 0xce,
	0x30, 0xc4, 0xc5, 0x31, 0xc7, 0x33, 0x32, 0xc6, 0xc3, 0x37, 0x36, 0xc2, 0x34, 0xc0, 0xc1, 0x35,
	0x20, 0xd4, 0xd5, 0x21, 0xd7, 0x23, 0x22, 0xd6, 0xd3, 0x27, 0x26, 0xd2, 0x24, 0xd0, 0xd1, 0x25,
	0xdb, 0x2f, 0x2e, 0xda, 0x2c, 0xd8, 0xd9, 0x2d, 0x28, 0xdc, 0xdd, 0x29, 0xdf, 0x2b, 0x2a, 0xde,
	0x8b, 0x7f, 0x7e, 0x8a, 0x7c, 0x88, 0x89, 0x7d, 0x78, 0x8c, 0x8d, 0x79, 0x8f, 0x7b, 0x7a, 0x8e,
	0x70, 0x84, 0x85, 0x71, 0x87, 0x73, 0x72, 0x86, 0x83, 0x77, 0x76, 0x82, 0x74, 0x80, 0x81, 0x75,
	0x60, 0x94, 0x95, 0x61, 0x97, 0x63, 0x62, 0x96, 0x93, 0x67, 0x66, 0x92, 0x64, 0x90, 0x91, 0x65,
	0x9b, 0x6f, 0x6e, 0x9a, 0x6c, 0x98, 0x99, 0x6d, 0x68, 0x9c, 0x9d, 0x69, 0x9f, 0x6b, 0x6a, 0x9e,
	0x40, 0xb4, 0xb5, 0x41, 0xb7, 0x43, 0x42, 0xb6, 0xb3, 0x47, 0x46, 0xb2, 0x44, 0xb0, 0xb1, 0x45,
	0xbb, 0x4f, 0x4e, 0xba, 0x4c, 0xb8, 0xb9, 0x4d, 0x48, 0xbc, 0xbd, 0x49, 0xbf, 0x4b, 0x4a, 0xbe,
	0xab, 0x5f, 0x5e, 0xaa, 0x5c, 0xa8, 0xa9, 0x5d, 0x58, 0xac, 0xad, 0x59, 0xaf, 0x5b, 0x5a, 0xae,
	0x50, 0xa4, 0xa5, 0x51, 0xa7, 0x53, 0x52, 0xa6, 0xa3, 0x57, 0x56, 0xa2, 0x54, 0xa0, 0xa1, 0x55
};


//-------------------------------------------------
//  poffsets - each row represents the addresses 
//  used to calculate a byte of the ECC P data
//	86 (*2) ECC P bytes, 24 values represented by
//	each
//-------------------------------------------------

static const UINT16 poffsets[ECC_P_NUM_BYTES][ECC_P_COMP] =
{
	{ 0x000,0x056,0x0ac,0x102,0x158,0x1ae,0x204,0x25a,0x2b0,0x306,0x35c,0x3b2,0x408,0x45e,0x4b4,0x50a,0x560,0x5b6,0x60c,0x662,0x6b8,0x70e,0x764,0x7ba },
	{ 0x001,0x057,0x0ad,0x103,0x159,0x1af,0x205,0x25b,0x2b1,0x307,0x35d,0x3b3,0x409,0x45f,0x4b5,0x50b,0x561,0x5b7,0x60d,0x663,0x6b9,0x70f,0x765,0x7bb },
	{ 0x002,0x058,0x0ae,0x104,0x15a,0x1b0,0x206,0x25c,0x2b2,0x308,0x35e,0x3b4,0x40a,0x460,0x4b6,0x50c,0x562,0x5b8,0x60e,0x664,0x6ba,0x710,0x766,0x7bc },
	{ 0x003,0x059,0x0af,0x105,0x15b,0x1b1,0x207,0x25d,0x2b3,0x309,0x35f,0x3b5,0x40b,0x461,0x4b7,0x50d,0x563,0x5b9,0x60f,0x665,0x6bb,0x711,0x767,0x7bd },
	{ 0x004,0x05a,0x0b0,0x106,0x15c,0x1b2,0x208,0x25e,0x2b4,0x30a,0x360,0x3b6,0x40c,0x462,0x4b8,0x50e,0x564,0x5ba,0x610,0x666,0x6bc,0x712,0x768,0x7be },
	{ 0x005,0x05b,0x0b1,0x107,0x15d,0x1b3,0x209,0x25f,0x2b5,0x30b,0x361,0x3b7,0x40d,0x463,0x4b9,0x50f,0x565,0x5bb,0x611,0x667,0x6bd,0x713,0x769,0x7bf },
	{ 0x006,0x05c,0x0b2,0x108,0x15e,0x1b4,0x20a,0x260,0x2b6,0x30c,0x362,0x3b8,0x40e,0x464,0x4ba,0x510,0x566,0x5bc,0x612,0x668,0x6be,0x714,0x76a,0x7c0 },
	{ 0x007,0x05d,0x0b3,0x109,0x15f,0x1b5,0x20b,0x261,0x2b7,0x30d,0x363,0x3b9,0x40f,0x465,0x4bb,0x511,0x567,0x5bd,0x613,0x669,0x6bf,0x715,0x76b,0x7c1 },
	{ 0x008,0x05e,0x0b4,0x10a,0x160,0x1b6,0x20c,0x262,0x2b8,0x30e,0x364,0x3ba,0x410,0x466,0x4bc,0x512,0x568,0x5be,0x614,0x66a,0x6c0,0x716,0x76c,0x7c2 },
	{ 0x009,0x05f,0x0b5,0x10b,0x161,0x1b7,0x20d,0x263,0x2b9,0x30f,0x365,0x3bb,0x411,0x467,0x4bd,0x513,0x569,0x5bf,0x615,0x66b,0x6c1,0x717,0x76d,0x7c3 },
	{ 0x00a,0x060,0x0b6,0x10c,0x162,0x1b8,0x20e,0x264,0x2ba,0x310,0x366,0x3bc,0x412,0x468,0x4be,0x514,0x56a,0x5c0,0x616,0x66c,0x6c2,0x718,0x76e,0x7c4 },
	{ 0x00b,0x061,0x0b7,0x10d,0x163,0x1b9,0x20f,0x265,0x2bb,0x311,0x367,0x3bd,0x413,0x469,0x4bf,0x515,0x56b,0x5c1,0x617,0x66d,0x6c3,0x719,0x76f,0x7c5 },
	{ 0x00c,0x062,0x0b8,0x10e,0x164,0x1ba,0x210,0x266,0x2bc,0x312,0x368,0x3be,0x414,0x46a,0x4c0,0x516,0x56c,0x5c2,0x618,0x66e,0x6c4,0x71a,0x770,0x7c6 },
	{ 0x00d,0x063,0x0b9,0x10f,0x165,0x1bb,0x211,0x267,0x2bd,0x313,0x369,0x3bf,0x415,0x46b,0x4c1,0x517,0x56d,0x5c3,0x619,0x66f,0x6c5,0x71b,0x771,0x7c7 },
	{ 0x00e,0x064,0x0ba,0x110,0x166,0x1bc,0x212,0x268,0x2be,0x314,0x36a,0x3c0,0x416,0x46c,0x4c2,0x518,0x56e,0x5c4,0x61a,0x670,0x6c6,0x71c,0x772,0x7c8 },
	{ 0x00f,0x065,0x0bb,0x111,0x167,0x1bd,0x213,0x269,0x2bf,0x315,0x36b,0x3c1,0x417,0x46d,0x4c3,0x519,0x56f,0x5c5,0x61b,0x671,0x6c7,0x71d,0x773,0x7c9 },
	{ 0x010,0x066,0x0bc,0x112,0x168,0x1be,0x214,0x26a,0x2c0,0x316,0x36c,0x3c2,0x418,0x46e,0x4c4,0x51a,0x570,0x5c6,0x61c,0x672,0x6c8,0x71e,0x774,0x7ca },
	{ 0x011,0x067,0x0bd,0x113,0x169,0x1bf,0x215,0x26b,0x2c1,0x317,0x36d,0x3c3,0x419,0x46f,0x4c5,0x51b,0x571,0x5c7,0x61d,0x673,0x6c9,0x71f,0x775,0x7cb },
	{ 0x012,0x068,0x0be,0x114,0x16a,0x1c0,0x216,0x26c,0x2c2,0x318,0x36e,0x3c4,0x41a,0x470,0x4c6,0x51c,0x572,0x5c8,0x61e,0x674,0x6ca,0x720,0x776,0x7cc },
	{ 0x013,0x069,0x0bf,0x115,0x16b,0x1c1,0x217,0x26d,0x2c3,0x319,0x36f,0x3c5,0x41b,0x471,0x4c7,0x51d,0x573,0x5c9,0x61f,0x675,0x6cb,0x721,0x777,0x7cd },
	{ 0x014,0x06a,0x0c0,0x116,0x16c,0x1c2,0x218,0x26e,0x2c4,0x31a,0x370,0x3c6,0x41c,0x472,0x4c8,0x51e,0x574,0x5ca,0x620,0x676,0x6cc,0x722,0x778,0x7ce },
	{ 0x015,0x06b,0x0c1,0x117,0x16d,0x1c3,0x219,0x26f,0x2c5,0x31b,0x371,0x3c7,0x41d,0x473,0x4c9,0x51f,0x575,0x5cb,0x621,0x677,0x6cd,0x723,0x779,0x7cf },
	{ 0x016,0x06c,0x0c2,0x118,0x16e,0x1c4,0x21a,0x270,0x2c6,0x31c,0x372,0x3c8,0x41e,0x474,0x4ca,0x520,0x576,0x5cc,0x622,0x678,0x6ce,0x724,0x77a,0x7d0 },
	{ 0x017,0x06d,0x0c3,0x119,0x16f,0x1c5,0x21b,0x271,0x2c7,0x31d,0x373,0x3c9,0x41f,0x475,0x4cb,0x521,0x577,0x5cd,0x623,0x679,0x6cf,0x725,0x77b,0x7d1 },
	{ 0x018,0x06e,0x0c4,0x11a,0x170,0x1c6,0x21c,0x272,0x2c8,0x31e,0x374,0x3ca,0x420,0x476,0x4cc,0x522,0x578,0x5ce,0x624,0x67a,0x6d0,0x726,0x77c,0x7d2 },
	{ 0x019,0x06f,0x0c5,0x11b,0x171,0x1c7,0x21d,0x273,0x2c9,0x31f,0x375,0x3cb,0x421,0x477,0x4cd,0x523,0x579,0x5cf,0x625,0x67b,0x6d1,0x727,0x77d,0x7d3 },
	{ 0x01a,0x070,0x0c6,0x11c,0x172,0x1c8,0x21e,0x274,0x2ca,0x320,0x376,0x3cc,0x422,0x478,0x4ce,0x524,0x57a,0x5d0,0x626,0x67c,0x6d2,0x728,0x77e,0x7d4 },
	{ 0x01b,0x071,0x0c7,0x11d,0x173,0x1c9,0x21f,0x275,0x2cb,0x321,0x377,0x3cd,0x423,0x479,0x4cf,0x525,0x57b,0x5d1,0x627,0x67d,0x6d3,0x729,0x77f,0x7d5 },
	{ 0x01c,0x072,0x0c8,0x11e,0x174,0x1ca,0x220,0x276,0x2cc,0x322,0x378,0x3ce,0x424,0x47a,0x4d0,0x526,0x57c,0x5d2,0x628,0x67e,0x6d4,0x72a,0x780,0x7d6 },
	{ 0x01d,0x073,0x0c9,0x11f,0x175,0x1cb,0x221,0x277,0x2cd,0x323,0x379,0x3cf,0x425,0x47b,0x4d1,0x527,0x57d,0x5d3,0x629,0x67f,0x6d5,0x72b,0x781,0x7d7 },
	{ 0x01e,0x074,0x0ca,0x120,0x176,0x1cc,0x222,0x278,0x2ce,0x324,0x37a,0x3d0,0x426,0x47c,0x4d2,0x528,0x57e,0x5d4,0x62a,0x680,0x6d6,0x72c,0x782,0x7d8 },
	{ 0x01f,0x075,0x0cb,0x121,0x177,0x1cd,0x223,0x279,0x2cf,0x325,0x37b,0x3d1,0x427,0x47d,0x4d3,0x529,0x57f,0x5d5,0x62b,0x681,0x6d7,0x72d,0x783,0x7d9 },
	{ 0x020,0x076,0x0cc,0x122,0x178,0x1ce,0x224,0x27a,0x2d0,0x326,0x37c,0x3d2,0x428,0x47e,0x4d4,0x52a,0x580,0x5d6,0x62c,0x682,0x6d8,0x72e,0x784,0x7da },
	{ 0x021,0x077,0x0cd,0x123,0x179,0x1cf,0x225,0x27b,0x2d1,0x327,0x37d,0x3d3,0x429,0x47f,0x4d5,0x52b,0x581,0x5d7,0x62d,0x683,0x6d9,0x72f,0x785,0x7db },
	{ 0x022,0x078,0x0ce,0x124,0x17a,0x1d0,0x226,0x27c,0x2d2,0x328,0x37e,0x3d4,0x42a,0x480,0x4d6,0x52c,0x582,0x5d8,0x62e,0x684,0x6da,0x730,0x786,0x7dc },
	{ 0x023,0x079,0x0cf,0x125,0x17b,0x1d1,0x227,0x27d,0x2d3,0x329,0x37f,0x3d5,0x42b,0x481,0x4d7,0x52d,0x583,0x5d9,0x62f,0x685,0x6db,0x731,0x787,0x7dd },
	{ 0x024,0x07a,0x0d0,0x126,0x17c,0x1d2,0x228,0x27e,0x2d4,0x32a,0x380,0x3d6,0x42c,0x482,0x4d8,0x52e,0x584,0x5da,0x630,0x686,0x6dc,0x732,0x788,0x7de },
	{ 0x025,0x07b,0x0d1,0x127,0x17d,0x1d3,0x229,0x27f,0x2d5,0x32b,0x381,0x3d7,0x42d,0x483,0x4d9,0x52f,0x585,0x5db,0x631,0x687,0x6dd,0x733,0x789,0x7df },
	{ 0x026,0x07c,0x0d2,0x128,0x17e,0x1d4,0x22a,0x280,0x2d6,0x32c,0x382,0x3d8,0x42e,0x484,0x4da,0x530,0x586,0x5dc,0x632,0x688,0x6de,0x734,0x78a,0x7e0 },
	{ 0x027,0x07d,0x0d3,0x129,0x17f,0x1d5,0x22b,0x281,0x2d7,0x32d,0x383,0x3d9,0x42f,0x485,0x4db,0x531,0x587,0x5dd,0x633,0x689,0x6df,0x735,0x78b,0x7e1 },
	{ 0x028,0x07e,0x0d4,0x12a,0x180,0x1d6,0x22c,0x282,0x2d8,0x32e,0x384,0x3da,0x430,0x486,0x4dc,0x532,0x588,0x5de,0x634,0x68a,0x6e0,0x736,0x78c,0x7e2 },
	{ 0x029,0x07f,0x0d5,0x12b,0x181,0x1d7,0x22d,0x283,0x2d9,0x32f,0x385,0x3db,0x431,0x487,0x4dd,0x533,0x589,0x5df,0x635,0x68b,0x6e1,0x737,0x78d,0x7e3 },
	{ 0x02a,0x080,0x0d6,0x12c,0x182,0x1d8,0x22e,0x284,0x2da,0x330,0x386,0x3dc,0x432,0x488,0x4de,0x534,0x58a,0x5e0,0x636,0x68c,0x6e2,0x738,0x78e,0x7e4 },
	{ 0x02b,0x081,0x0d7,0x12d,0x183,0x1d9,0x22f,0x285,0x2db,0x331,0x387,0x3dd,0x433,0x489,0x4df,0x535,0x58b,0x5e1,0x637,0x68d,0x6e3,0x739,0x78f,0x7e5 },
	{ 0x02c,0x082,0x0d8,0x12e,0x184,0x1da,0x230,0x286,0x2dc,0x332,0x388,0x3de,0x434,0x48a,0x4e0,0x536,0x58c,0x5e2,0x638,0x68e,0x6e4,0x73a,0x790,0x7e6 },
	{ 0x02d,0x083,0x0d9,0x12f,0x185,0x1db,0x231,0x287,0x2dd,0x333,0x389,0x3df,0x435,0x48b,0x4e1,0x537,0x58d,0x5e3,0x639,0x68f,0x6e5,0x73b,0x791,0x7e7 },
	{ 0x02e,0x084,0x0da,0x130,0x186,0x1dc,0x232,0x288,0x2de,0x334,0x38a,0x3e0,0x436,0x48c,0x4e2,0x538,0x58e,0x5e4,0x63a,0x690,0x6e6,0x73c,0x792,0x7e8 },
	{ 0x02f,0x085,0x0db,0x131,0x187,0x1dd,0x233,0x289,0x2df,0x335,0x38b,0x3e1,0x437,0x48d,0x4e3,0x539,0x58f,0x5e5,0x63b,0x691,0x6e7,0x73d,0x793,0x7e9 },
	{ 0x030,0x086,0x0dc,0x132,0x188,0x1de,0x234,0x28a,0x2e0,0x336,0x38c,0x3e2,0x438,0x48e,0x4e4,0x53a,0x590,0x5e6,0x63c,0x692,0x6e8,0x73e,0x794,0x7ea },
	{ 0x031,0x087,0x0dd,0x133,0x189,0x1df,0x235,0x28b,0x2e1,0x337,0x38d,0x3e3,0x439,0x48f,0x4e5,0x53b,0x591,0x5e7,0x63d,0x693,0x6e9,0x73f,0x795,0x7eb },
	{ 0x032,0x088,0x0de,0x134,0x18a,0x1e0,0x236,0x28c,0x2e2,0x338,0x38e,0x3e4,0x43a,0x490,0x4e6,0x53c,0x592,0x5e8,0x63e,0x694,0x6ea,0x740,0x796,0x7ec },
	{ 0x033,0x089,0x0df,0x135,0x18b,0x1e1,0x237,0x28d,0x2e3,0x339,0x38f,0x3e5,0x43b,0x491,0x4e7,0x53d,0x593,0x5e9,0x63f,0x695,0x6eb,0x741,0x797,0x7ed },
	{ 0x034,0x08a,0x0e0,0x136,0x18c,0x1e2,0x238,0x28e,0x2e4,0x33a,0x390,0x3e6,0x43c,0x492,0x4e8,0x53e,0x594,0x5ea,0x640,0x696,0x6ec,0x742,0x798,0x7ee },
	{ 0x035,0x08b,0x0e1,0x137,0x18d,0x1e3,0x239,0x28f,0x2e5,0x33b,0x391,0x3e7,0x43d,0x493,0x4e9,0x53f,0x595,0x5eb,0x641,0x697,0x6ed,0x743,0x799,0x7ef },
	{ 0x036,0x08c,0x0e2,0x138,0x18e,0x1e4,0x23a,0x290,0x2e6,0x33c,0x392,0x3e8,0x43e,0x494,0x4ea,0x540,0x596,0x5ec,0x642,0x698,0x6ee,0x744,0x79a,0x7f0 },
	{ 0x037,0x08d,0x0e3,0x139,0x18f,0x1e5,0x23b,0x291,0x2e7,0x33d,0x393,0x3e9,0x43f,0x495,0x4eb,0x541,0x597,0x5ed,0x643,0x699,0x6ef,0x745,0x79b,0x7f1 },
	{ 0x038,0x08e,0x0e4,0x13a,0x190,0x1e6,0x23c,0x292,0x2e8,0x33e,0x394,0x3ea,0x440,0x496,0x4ec,0x542,0x598,0x5ee,0x644,0x69a,0x6f0,0x746,0x79c,0x7f2 },
	{ 0x039,0x08f,0x0e5,0x13b,0x191,0x1e7,0x23d,0x293,0x2e9,0x33f,0x395,0x3eb,0x441,0x497,0x4ed,0x543,0x599,0x5ef,0x645,0x69b,0x6f1,0x747,0x79d,0x7f3 },
	{ 0x03a,0x090,0x0e6,0x13c,0x192,0x1e8,0x23e,0x294,0x2ea,0x340,0x396,0x3ec,0x442,0x498,0x4ee,0x544,0x59a,0x5f0,0x646,0x69c,0x6f2,0x748,0x79e,0x7f4 },
	{ 0x03b,0x091,0x0e7,0x13d,0x193,0x1e9,0x23f,0x295,0x2eb,0x341,0x397,0x3ed,0x443,0x499,0x4ef,0x545,0x59b,0x5f1,0x647,0x69d,0x6f3,0x749,0x79f,0x7f5 },
	{ 0x03c,0x092,0x0e8,0x13e,0x194,0x1ea,0x240,0x296,0x2ec,0x342,0x398,0x3ee,0x444,0x49a,0x4f0,0x546,0x59c,0x5f2,0x648,0x69e,0x6f4,0x74a,0x7a0,0x7f6 },
	{ 0x03d,0x093,0x0e9,0x13f,0x195,0x1eb,0x241,0x297,0x2ed,0x343,0x399,0x3ef,0x445,0x49b,0x4f1,0x547,0x59d,0x5f3,0x649,0x69f,0x6f5,0x74b,0x7a1,0x7f7 },
	{ 0x03e,0x094,0x0ea,0x140,0x196,0x1ec,0x242,0x298,0x2ee,0x344,0x39a,0x3f0,0x446,0x49c,0x4f2,0x548,0x59e,0x5f4,0x64a,0x6a0,0x6f6,0x74c,0x7a2,0x7f8 },
	{ 0x03f,0x095,0x0eb,0x141,0x197,0x1ed,0x243,0x299,0x2ef,0x345,0x39b,0x3f1,0x447,0x49d,0x4f3,0x549,0x59f,0x5f5,0x64b,0x6a1,0x6f7,0x74d,0x7a3,0x7f9 },
	{ 0x040,0x096,0x0ec,0x142,0x198,0x1ee,0x244,0x29a,0x2f0,0x346,0x39c,0x3f2,0x448,0x49e,0x4f4,0x54a,0x5a0,0x5f6,0x64c,0x6a2,0x6f8,0x74e,0x7a4,0x7fa },
	{ 0x041,0x097,0x0ed,0x143,0x199,0x1ef,0x245,0x29b,0x2f1,0x347,0x39d,0x3f3,0x449,0x49f,0x4f5,0x54b,0x5a1,0x5f7,0x64d,0x6a3,0x6f9,0x74f,0x7a5,0x7fb },
	{ 0x042,0x098,0x0ee,0x144,0x19a,0x1f0,0x246,0x29c,0x2f2,0x348,0x39e,0x3f4,0x44a,0x4a0,0x4f6,0x54c,0x5a2,0x5f8,0x64e,0x6a4,0x6fa,0x750,0x7a6,0x7fc },
	{ 0x043,0x099,0x0ef,0x145,0x19b,0x1f1,0x247,0x29d,0x2f3,0x349,0x39f,0x3f5,0x44b,0x4a1,0x4f7,0x54d,0x5a3,0x5f9,0x64f,0x6a5,0x6fb,0x751,0x7a7,0x7fd },
	{ 0x044,0x09a,0x0f0,0x146,0x19c,0x1f2,0x248,0x29e,0x2f4,0x34a,0x3a0,0x3f6,0x44c,0x4a2,0x4f8,0x54e,0x5a4,0x5fa,0x650,0x6a6,0x6fc,0x752,0x7a8,0x7fe },
	{ 0x045,0x09b,0x0f1,0x147,0x19d,0x1f3,0x249,0x29f,0x2f5,0x34b,0x3a1,0x3f7,0x44d,0x4a3,0x4f9,0x54f,0x5a5,0x5fb,0x651,0x6a7,0x6fd,0x753,0x7a9,0x7ff },
	{ 0x046,0x09c,0x0f2,0x148,0x19e,0x1f4,0x24a,0x2a0,0x2f6,0x34c,0x3a2,0x3f8,0x44e,0x4a4,0x4fa,0x550,0x5a6,0x5fc,0x652,0x6a8,0x6fe,0x754,0x7aa,0x800 },
	{ 0x047,0x09d,0x0f3,0x149,0x19f,0x1f5,0x24b,0x2a1,0x2f7,0x34d,0x3a3,0x3f9,0x44f,0x4a5,0x4fb,0x551,0x5a7,0x5fd,0x653,0x6a9,0x6ff,0x755,0x7ab,0x801 },
	{ 0x048,0x09e,0x0f4,0x14a,0x1a0,0x1f6,0x24c,0x2a2,0x2f8,0x34e,0x3a4,0x3fa,0x450,0x4a6,0x4fc,0x552,0x5a8,0x5fe,0x654,0x6aa,0x700,0x756,0x7ac,0x802 },
	{ 0x049,0x09f,0x0f5,0x14b,0x1a1,0x1f7,0x24d,0x2a3,0x2f9,0x34f,0x3a5,0x3fb,0x451,0x4a7,0x4fd,0x553,0x5a9,0x5ff,0x655,0x6ab,0x701,0x757,0x7ad,0x803 },
	{ 0x04a,0x0a0,0x0f6,0x14c,0x1a2,0x1f8,0x24e,0x2a4,0x2fa,0x350,0x3a6,0x3fc,0x452,0x4a8,0x4fe,0x554,0x5aa,0x600,0x656,0x6ac,0x702,0x758,0x7ae,0x804 },
	{ 0x04b,0x0a1,0x0f7,0x14d,0x1a3,0x1f9,0x24f,0x2a5,0x2fb,0x351,0x3a7,0x3fd,0x453,0x4a9,0x4ff,0x555,0x5ab,0x601,0x657,0x6ad,0x703,0x759,0x7af,0x805 },
	{ 0x04c,0x0a2,0x0f8,0x14e,0x1a4,0x1fa,0x250,0x2a6,0x2fc,0x352,0x3a8,0x3fe,0x454,0x4aa,0x500,0x556,0x5ac,0x602,0x658,0x6ae,0x704,0x75a,0x7b0,0x806 },
	{ 0x04d,0x0a3,0x0f9,0x14f,0x1a5,0x1fb,0x251,0x2a7,0x2fd,0x353,0x3a9,0x3ff,0x455,0x4ab,0x501,0x557,0x5ad,0x603,0x659,0x6af,0x705,0x75b,0x7b1,0x807 },
	{ 0x04e,0x0a4,0x0fa,0x150,0x1a6,0x1fc,0x252,0x2a8,0x2fe,0x354,0x3aa,0x400,0x456,0x4ac,0x502,0x558,0x5ae,0x604,0x65a,0x6b0,0x706,0x75c,0x7b2,0x808 },
	{ 0x04f,0x0a5,0x0fb,0x151,0x1a7,0x1fd,0x253,0x2a9,0x2ff,0x355,0x3ab,0x401,0x457,0x4ad,0x503,0x559,0x5af,0x605,0x65b,0x6b1,0x707,0x75d,0x7b3,0x809 },
	{ 0x050,0x0a6,0x0fc,0x152,0x1a8,0x1fe,0x254,0x2aa,0x300,0x356,0x3ac,0x402,0x458,0x4ae,0x504,0x55a,0x5b0,0x606,0x65c,0x6b2,0x708,0x75e,0x7b4,0x80a },
	{ 0x051,0x0a7,0x0fd,0x153,0x1a9,0x1ff,0x255,0x2ab,0x301,0x357,0x3ad,0x403,0x459,0x4af,0x505,0x55b,0x5b1,0x607,0x65d,0x6b3,0x709,0x75f,0x7b5,0x80b },
	{ 0x052,0x0a8,0x0fe,0x154,0x1aa,0x200,0x256,0x2ac,0x302,0x358,0x3ae,0x404,0x45a,0x4b0,0x506,0x55c,0x5b2,0x608,0x65e,0x6b4,0x70a,0x760,0x7b6,0x80c },
	{ 0x053,0x0a9,0x0ff,0x155,0x1ab,0x201,0x257,0x2ad,0x303,0x359,0x3af,0x405,0x45b,0x4b1,0x507,0x55d,0x5b3,0x609,0x65f,0x6b5,0x70b,0x761,0x7b7,0x80d },
	{ 0x054,0x0aa,0x100,0x156,0x1ac,0x202,0x258,0x2ae,0x304,0x35a,0x3b0,0x406,0x45c,0x4b2,0x508,0x55e,0x5b4,0x60a,0x660,0x6b6,0x70c,0x762,0x7b8,0x80e },
	{ 0x055,0x0ab,0x101,0x157,0x1ad,0x203,0x259,0x2af,0x305,0x35b,0x3b1,0x407,0x45d,0x4b3,0x509,0x55f,0x5b5,0x60b,0x661,0x6b7,0x70d,0x763,0x7b9,0x80f }
};


//-------------------------------------------------
//  qoffsets - each row represents the addresses 
//  used to calculate a byte of the ECC Q data
//	52 (*2) ECC Q bytes, 43 values represented by
//	each
//-------------------------------------------------

static const UINT16 qoffsets[ECC_Q_NUM_BYTES][ECC_Q_COMP] =
{
	{ 0x000,0x058,0x0b0,0x108,0x160,0x1b8,0x210,0x268,0x2c0,0x318,0x370,0x3c8,0x420,0x478,0x4d0,0x528,0x580,0x5d8,0x630,0x688,0x6e0,0x738,0x790,0x7e8,0x840,0x898,0x034,0x08c,0x0e4,0x13c,0x194,0x1ec,0x244,0x29c,0x2f4,0x34c,0x3a4,0x3fc,0x454,0x4ac,0x504,0x55c,0x5b4 },
	{ 0x001,0x059,0x0b1,0x109,0x161,0x1b9,0x211,0x269,0x2c1,0x319,0x371,0x3c9,0x421,0x479,0x4d1,0x529,0x581,0x5d9,0x631,0x689,0x6e1,0x739,0x791,0x7e9,0x841,0x899,0x035,0x08d,0x0e5,0x13d,0x195,0x1ed,0x245,0x29d,0x2f5,0x34d,0x3a5,0x3fd,0x455,0x4ad,0x505,0x55d,0x5b5 },
	{ 0x056,0x0ae,0x106,0x15e,0x1b6,0x20e,0x266,0x2be,0x316,0x36e,0x3c6,0x41e,0x476,0x4ce,0x526,0x57e,0x5d6,0x62e,0x686,0x6de,0x736,0x78e,0x7e6,0x83e,0x896,0x032,0x08a,0x0e2,0x13a,0x192,0x1ea,0x242,0x29a,0x2f2,0x34a,0x3a2,0x3fa,0x452,0x4aa,0x502,0x55a,0x5b2,0x60a },
	{ 0x057,0x0af,0x107,0x15f,0x1b7,0x20f,0x267,0x2bf,0x317,0x36f,0x3c7,0x41f,0x477,0x4cf,0x527,0x57f,0x5d7,0x62f,0x687,0x6df,0x737,0x78f,0x7e7,0x83f,0x897,0x033,0x08b,0x0e3,0x13b,0x193,0x1eb,0x243,0x29b,0x2f3,0x34b,0x3a3,0x3fb,0x453,0x4ab,0x503,0x55b,0x5b3,0x60b },
	{ 0x0ac,0x104,0x15c,0x1b4,0x20c,0x264,0x2bc,0x314,0x36c,0x3c4,0x41c,0x474,0x4cc,0x524,0x57c,0x5d4,0x62c,0x684,0x6dc,0x734,0x78c,0x7e4,0x83c,0x894,0x030,0x088,0x0e0,0x138,0x190,0x1e8,0x240,0x298,0x2f0,0x348,0x3a0,0x3f8,0x450,0x4a8,0x500,0x558,0x5b0,0x608,0x660 },
	{ 0x0ad,0x105,0x15d,0x1b5,0x20d,0x265,0x2bd,0x315,0x36d,0x3c5,0x41d,0x475,0x4cd,0x525,0x57d,0x5d5,0x62d,0x685,0x6dd,0x735,0x78d,0x7e5,0x83d,0x895,0x031,0x089,0x0e1,0x139,0x191,0x1e9,0x241,0x299,0x2f1,0x349,0x3a1,0x3f9,0x451,0x4a9,0x501,0x559,0x5b1,0x609,0x661 },
	{ 0x102,0x15a,0x1b2,0x20a,0x262,0x2ba,0x312,0x36a,0x3c2,0x41a,0x472,0x4ca,0x522,0x57a,0x5d2,0x62a,0x682,0x6da,0x732,0x78a,0x7e2,0x83a,0x892,0x02e,0x086,0x0de,0x136,0x18e,0x1e6,0x23e,0x296,0x2ee,0x346,0x39e,0x3f6,0x44e,0x4a6,0x4fe,0x556,0x5ae,0x606,0x65e,0x6b6 },
	{ 0x103,0x15b,0x1b3,0x20b,0x263,0x2bb,0x313,0x36b,0x3c3,0x41b,0x473,0x4cb,0x523,0x57b,0x5d3,0x62b,0x683,0x6db,0x733,0x78b,0x7e3,0x83b,0x893,0x02f,0x087,0x0df,0x137,0x18f,0x1e7,0x23f,0x297,0x2ef,0x347,0x39f,0x3f7,0x44f,0x4a7,0x4ff,0x557,0x5af,0x607,0x65f,0x6b7 },
	{ 0x158,0x1b0,0x208,0x260,0x2b8,0x310,0x368,0x3c0,0x418,0x470,0x4c8,0x520,0x578,0x5d0,0x628,0x680,0x6d8,0x730,0x788,0x7e0,0x838,0x890,0x02c,0x084,0x0dc,0x134,0x18c,0x1e4,0x23c,0x294,0x2ec,0x344,0x39c,0x3f4,0x44c,0x4a4,0x4fc,0x554,0x5ac,0x604,0x65c,0x6b4,0x70c },
	{ 0x159,0x1b1,0x209,0x261,0x2b9,0x311,0x369,0x3c1,0x419,0x471,0x4c9,0x521,0x579,0x5d1,0x629,0x681,0x6d9,0x731,0x789,0x7e1,0x839,0x891,0x02d,0x085,0x0dd,0x135,0x18d,0x1e5,0x23d,0x295,0x2ed,0x345,0x39d,0x3f5,0x44d,0x4a5,0x4fd,0x555,0x5ad,0x605,0x65d,0x6b5,0x70d },
	{ 0x1ae,0x206,0x25e,0x2b6,0x30e,0x366,0x3be,0x416,0x46e,0x4c6,0x51e,0x576,0x5ce,0x626,0x67e,0x6d6,0x72e,0x786,0x7de,0x836,0x88e,0x02a,0x082,0x0da,0x132,0x18a,0x1e2,0x23a,0x292,0x2ea,0x342,0x39a,0x3f2,0x44a,0x4a2,0x4fa,0x552,0x5aa,0x602,0x65a,0x6b2,0x70a,0x762 },
	{ 0x1af,0x207,0x25f,0x2b7,0x30f,0x367,0x3bf,0x417,0x46f,0x4c7,0x51f,0x577,0x5cf,0x627,0x67f,0x6d7,0x72f,0x787,0x7df,0x837,0x88f,0x02b,0x083,0x0db,0x133,0x18b,0x1e3,0x23b,0x293,0x2eb,0x343,0x39b,0x3f3,0x44b,0x4a3,0x4fb,0x553,0x5ab,0x603,0x65b,0x6b3,0x70b,0x763 },
	{ 0x204,0x25c,0x2b4,0x30c,0x364,0x3bc,0x414,0x46c,0x4c4,0x51c,0x574,0x5cc,0x624,0x67c,0x6d4,0x72c,0x784,0x7dc,0x834,0x88c,0x028,0x080,0x0d8,0x130,0x188,0x1e0,0x238,0x290,0x2e8,0x340,0x398,0x3f0,0x448,0x4a0,0x4f8,0x550,0x5a8,0x600,0x658,0x6b0,0x708,0x760,0x7b8 },
	{ 0x205,0x25d,0x2b5,0x30d,0x365,0x3bd,0x415,0x46d,0x4c5,0x51d,0x575,0x5cd,0x625,0x67d,0x6d5,0x72d,0x785,0x7dd,0x835,0x88d,0x029,0x081,0x0d9,0x131,0x189,0x1e1,0x239,0x291,0x2e9,0x341,0x399,0x3f1,0x449,0x4a1,0x4f9,0x551,0x5a9,0x601,0x659,0x6b1,0x709,0x761,0x7b9 },
	{ 0x25a,0x2b2,0x30a,0x362,0x3ba,0x412,0x46a,0x4c2,0x51a,0x572,0x5ca,0x622,0x67a,0x6d2,0x72a,0x782,0x7da,0x832,0x88a,0x026,0x07e,0x0d6,0x12e,0x186,0x1de,0x236,0x28e,0x2e6,0x33e,0x396,0x3ee,0x446,0x49e,0x4f6,0x54e,0x5a6,0x5fe,0x656,0x6ae,0x706,0x75e,0x7b6,0x80e },
	{ 0x25b,0x2b3,0x30b,0x363,0x3bb,0x413,0x46b,0x4c3,0x51b,0x573,0x5cb,0x623,0x67b,0x6d3,0x72b,0x783,0x7db,0x833,0x88b,0x027,0x07f,0x0d7,0x12f,0x187,0x1df,0x237,0x28f,0x2e7,0x33f,0x397,0x3ef,0x447,0x49f,0x4f7,0x54f,0x5a7,0x5ff,0x657,0x6af,0x707,0x75f,0x7b7,0x80f },
	{ 0x2b0,0x308,0x360,0x3b8,0x410,0x468,0x4c0,0x518,0x570,0x5c8,0x620,0x678,0x6d0,0x728,0x780,0x7d8,0x830,0x888,0x024,0x07c,0x0d4,0x12c,0x184,0x1dc,0x234,0x28c,0x2e4,0x33c,0x394,0x3ec,0x444,0x49c,0x4f4,0x54c,0x5a4,0x5fc,0x654,0x6ac,0x704,0x75c,0x7b4,0x80c,0x864 },
	{ 0x2b1,0x309,0x361,0x3b9,0x411,0x469,0x4c1,0x519,0x571,0x5c9,0x621,0x679,0x6d1,0x729,0x781,0x7d9,0x831,0x889,0x025,0x07d,0x0d5,0x12d,0x185,0x1dd,0x235,0x28d,0x2e5,0x33d,0x395,0x3ed,0x445,0x49d,0x4f5,0x54d,0x5a5,0x5fd,0x655,0x6ad,0x705,0x75d,0x7b5,0x80d,0x865 },
	{ 0x306,0x35e,0x3b6,0x40e,0x466,0x4be,0x516,0x56e,0x5c6,0x61e,0x676,0x6ce,0x726,0x77e,0x7d6,0x82e,0x886,0x022,0x07a,0x0d2,0x12a,0x182,0x1da,0x232,0x28a,0x2e2,0x33a,0x392,0x3ea,0x442,0x49a,0x4f2,0x54a,0x5a2,0x5fa,0x652,0x6aa,0x702,0x75a,0x7b2,0x80a,0x862,0x8ba },
	{ 0x307,0x35f,0x3b7,0x40f,0x467,0x4bf,0x517,0x56f,0x5c7,0x61f,0x677,0x6cf,0x727,0x77f,0x7d7,0x82f,0x887,0x023,0x07b,0x0d3,0x12b,0x183,0x1db,0x233,0x28b,0x2e3,0x33b,0x393,0x3eb,0x443,0x49b,0x4f3,0x54b,0x5a3,0x5fb,0x653,0x6ab,0x703,0x75b,0x7b3,0x80b,0x863,0x8bb },
	{ 0x35c,0x3b4,0x40c,0x464,0x4bc,0x514,0x56c,0x5c4,0x61c,0x674,0x6cc,0x724,0x77c,0x7d4,0x82c,0x884,0x020,0x078,0x0d0,0x128,0x180,0x1d8,0x230,0x288,0x2e0,0x338,0x390,0x3e8,0x440,0x498,0x4f0,0x548,0x5a0,0x5f8,0x650,0x6a8,0x700,0x758,0x7b0,0x808,0x860,0x8b8,0x054 },
	{ 0x35d,0x3b5,0x40d,0x465,0x4bd,0x515,0x56d,0x5c5,0x61d,0x675,0x6cd,0x725,0x77d,0x7d5,0x82d,0x885,0x021,0x079,0x0d1,0x129,0x181,0x1d9,0x231,0x289,0x2e1,0x339,0x391,0x3e9,0x441,0x499,0x4f1,0x549,0x5a1,0x5f9,0x651,0x6a9,0x701,0x759,0x7b1,0x809,0x861,0x8b9,0x055 },
	{ 0x3b2,0x40a,0x462,0x4ba,0x512,0x56a,0x5c2,0x61a,0x672,0x6ca,0x722,0x77a,0x7d2,0x82a,0x882,0x01e,0x076,0x0ce,0x126,0x17e,0x1d6,0x22e,0x286,0x2de,0x336,0x38e,0x3e6,0x43e,0x496,0x4ee,0x546,0x59e,0x5f6,0x64e,0x6a6,0x6fe,0x756,0x7ae,0x806,0x85e,0x8b6,0x052,0x0aa },
	{ 0x3b3,0x40b,0x463,0x4bb,0x513,0x56b,0x5c3,0x61b,0x673,0x6cb,0x723,0x77b,0x7d3,0x82b,0x883,0x01f,0x077,0x0cf,0x127,0x17f,0x1d7,0x22f,0x287,0x2df,0x337,0x38f,0x3e7,0x43f,0x497,0x4ef,0x547,0x59f,0x5f7,0x64f,0x6a7,0x6ff,0x757,0x7af,0x807,0x85f,0x8b7,0x053,0x0ab },
	{ 0x408,0x460,0x4b8,0x510,0x568,0x5c0,0x618,0x670,0x6c8,0x720,0x778,0x7d0,0x828,0x880,0x01c,0x074,0x0cc,0x124,0x17c,0x1d4,0x22c,0x284,0x2dc,0x334,0x38c,0x3e4,0x43c,0x494,0x4ec,0x544,0x59c,0x5f4,0x64c,0x6a4,0x6fc,0x754,0x7ac,0x804,0x85c,0x8b4,0x050,0x0a8,0x100 },
	{ 0x409,0x461,0x4b9,0x511,0x569,0x5c1,0x619,0x671,0x6c9,0x721,0x779,0x7d1,0x829,0x881,0x01d,0x075,0x0cd,0x125,0x17d,0x1d5,0x22d,0x285,0x2dd,0x335,0x38d,0x3e5,0x43d,0x495,0x4ed,0x545,0x59d,0x5f5,0x64d,0x6a5,0x6fd,0x755,0x7ad,0x805,0x85d,0x8b5,0x051,0x0a9,0x101 },
	{ 0x45e,0x4b6,0x50e,0x566,0x5be,0x616,0x66e,0x6c6,0x71e,0x776,0x7ce,0x826,0x87e,0x01a,0x072,0x0ca,0x122,0x17a,0x1d2,0x22a,0x282,0x2da,0x332,0x38a,0x3e2,0x43a,0x492,0x4ea,0x542,0x59a,0x5f2,0x64a,0x6a2,0x6fa,0x752,0x7aa,0x802,0x85a,0x8b2,0x04e,0x0a6,0x0fe,0x156 },
	{ 0x45f,0x4b7,0x50f,0x567,0x5bf,0x617,0x66f,0x6c7,0x71f,0x777,0x7cf,0x827,0x87f,0x01b,0x073,0x0cb,0x123,0x17b,0x1d3,0x22b,0x283,0x2db,0x333,0x38b,0x3e3,0x43b,0x493,0x4eb,0x543,0x59b,0x5f3,0x64b,0x6a3,0x6fb,0x753,0x7ab,0x803,0x85b,0x8b3,0x04f,0x0a7,0x0ff,0x157 },
	{ 0x4b4,0x50c,0x564,0x5bc,0x614,0x66c,0x6c4,0x71c,0x774,0x7cc,0x824,0x87c,0x018,0x070,0x0c8,0x120,0x178,0x1d0,0x228,0x280,0x2d8,0x330,0x388,0x3e0,0x438,0x490,0x4e8,0x540,0x598,0x5f0,0x648,0x6a0,0x6f8,0x750,0x7a8,0x800,0x858,0x8b0,0x04c,0x0a4,0x0fc,0x154,0x1ac },
	{ 0x4b5,0x50d,0x565,0x5bd,0x615,0x66d,0x6c5,0x71d,0x775,0x7cd,0x825,0x87d,0x019,0x071,0x0c9,0x121,0x179,0x1d1,0x229,0x281,0x2d9,0x331,0x389,0x3e1,0x439,0x491,0x4e9,0x541,0x599,0x5f1,0x649,0x6a1,0x6f9,0x751,0x7a9,0x801,0x859,0x8b1,0x04d,0x0a5,0x0fd,0x155,0x1ad },
	{ 0x50a,0x562,0x5ba,0x612,0x66a,0x6c2,0x71a,0x772,0x7ca,0x822,0x87a,0x016,0x06e,0x0c6,0x11e,0x176,0x1ce,0x226,0x27e,0x2d6,0x32e,0x386,0x3de,0x436,0x48e,0x4e6,0x53e,0x596,0x5ee,0x646,0x69e,0x6f6,0x74e,0x7a6,0x7fe,0x856,0x8ae,0x04a,0x0a2,0x0fa,0x152,0x1aa,0x202 },
	{ 0x50b,0x563,0x5bb,0x613,0x66b,0x6c3,0x71b,0x773,0x7cb,0x823,0x87b,0x017,0x06f,0x0c7,0x11f,0x177,0x1cf,0x227,0x27f,0x2d7,0x32f,0x387,0x3df,0x437,0x48f,0x4e7,0x53f,0x597,0x5ef,0x647,0x69f,0x6f7,0x74f,0x7a7,0x7ff,0x857,0x8af,0x04b,0x0a3,0x0fb,0x153,0x1ab,0x203 },
	{ 0x560,0x5b8,0x610,0x668,0x6c0,0x718,0x770,0x7c8,0x820,0x878,0x014,0x06c,0x0c4,0x11c,0x174,0x1cc,0x224,0x27c,0x2d4,0x32c,0x384,0x3dc,0x434,0x48c,0x4e4,0x53c,0x594,0x5ec,0x644,0x69c,0x6f4,0x74c,0x7a4,0x7fc,0x854,0x8ac,0x048,0x0a0,0x0f8,0x150,0x1a8,0x200,0x258 },
	{ 0x561,0x5b9,0x611,0x669,0x6c1,0x719,0x771,0x7c9,0x821,0x879,0x015,0x06d,0x0c5,0x11d,0x175,0x1cd,0x225,0x27d,0x2d5,0x32d,0x385,0x3dd,0x435,0x48d,0x4e5,0x53d,0x595,0x5ed,0x645,0x69d,0x6f5,0x74d,0x7a5,0x7fd,0x855,0x8ad,0x049,0x0a1,0x0f9,0x151,0x1a9,0x201,0x259 },
	{ 0x5b6,0x60e,0x666,0x6be,0x716,0x76e,0x7c6,0x81e,0x876,0x012,0x06a,0x0c2,0x11a,0x172,0x1ca,0x222,0x27a,0x2d2,0x32a,0x382,0x3da,0x432,0x48a,0x4e2,0x53a,0x592,0x5ea,0x642,0x69a,0x6f2,0x74a,0x7a2,0x7fa,0x852,0x8aa,0x046,0x09e,0x0f6,0x14e,0x1a6,0x1fe,0x256,0x2ae },
	{ 0x5b7,0x60f,0x667,0x6bf,0x717,0x76f,0x7c7,0x81f,0x877,0x013,0x06b,0x0c3,0x11b,0x173,0x1cb,0x223,0x27b,0x2d3,0x32b,0x383,0x3db,0x433,0x48b,0x4e3,0x53b,0x593,0x5eb,0x643,0x69b,0x6f3,0x74b,0x7a3,0x7fb,0x853,0x8ab,0x047,0x09f,0x0f7,0x14f,0x1a7,0x1ff,0x257,0x2af },
	{ 0x60c,0x664,0x6bc,0x714,0x76c,0x7c4,0x81c,0x874,0x010,0x068,0x0c0,0x118,0x170,0x1c8,0x220,0x278,0x2d0,0x328,0x380,0x3d8,0x430,0x488,0x4e0,0x538,0x590,0x5e8,0x640,0x698,0x6f0,0x748,0x7a0,0x7f8,0x850,0x8a8,0x044,0x09c,0x0f4,0x14c,0x1a4,0x1fc,0x254,0x2ac,0x304 },
	{ 0x60d,0x665,0x6bd,0x715,0x76d,0x7c5,0x81d,0x875,0x011,0x069,0x0c1,0x119,0x171,0x1c9,0x221,0x279,0x2d1,0x329,0x381,0x3d9,0x431,0x489,0x4e1,0x539,0x591,0x5e9,0x641,0x699,0x6f1,0x749,0x7a1,0x7f9,0x851,0x8a9,0x045,0x09d,0x0f5,0x14d,0x1a5,0x1fd,0x255,0x2ad,0x305 },
	{ 0x662,0x6ba,0x712,0x76a,0x7c2,0x81a,0x872,0x00e,0x066,0x0be,0x116,0x16e,0x1c6,0x21e,0x276,0x2ce,0x326,0x37e,0x3d6,0x42e,0x486,0x4de,0x536,0x58e,0x5e6,0x63e,0x696,0x6ee,0x746,0x79e,0x7f6,0x84e,0x8a6,0x042,0x09a,0x0f2,0x14a,0x1a2,0x1fa,0x252,0x2aa,0x302,0x35a },
	{ 0x663,0x6bb,0x713,0x76b,0x7c3,0x81b,0x873,0x00f,0x067,0x0bf,0x117,0x16f,0x1c7,0x21f,0x277,0x2cf,0x327,0x37f,0x3d7,0x42f,0x487,0x4df,0x537,0x58f,0x5e7,0x63f,0x697,0x6ef,0x747,0x79f,0x7f7,0x84f,0x8a7,0x043,0x09b,0x0f3,0x14b,0x1a3,0x1fb,0x253,0x2ab,0x303,0x35b },
	{ 0x6b8,0x710,0x768,0x7c0,0x818,0x870,0x00c,0x064,0x0bc,0x114,0x16c,0x1c4,0x21c,0x274,0x2cc,0x324,0x37c,0x3d4,0x42c,0x484,0x4dc,0x534,0x58c,0x5e4,0x63c,0x694,0x6ec,0x744,0x79c,0x7f4,0x84c,0x8a4,0x040,0x098,0x0f0,0x148,0x1a0,0x1f8,0x250,0x2a8,0x300,0x358,0x3b0 },
	{ 0x6b9,0x711,0x769,0x7c1,0x819,0x871,0x00d,0x065,0x0bd,0x115,0x16d,0x1c5,0x21d,0x275,0x2cd,0x325,0x37d,0x3d5,0x42d,0x485,0x4dd,0x535,0x58d,0x5e5,0x63d,0x695,0x6ed,0x745,0x79d,0x7f5,0x84d,0x8a5,0x041,0x099,0x0f1,0x149,0x1a1,0x1f9,0x251,0x2a9,0x301,0x359,0x3b1 },
	{ 0x70e,0x766,0x7be,0x816,0x86e,0x00a,0x062,0x0ba,0x112,0x16a,0x1c2,0x21a,0x272,0x2ca,0x322,0x37a,0x3d2,0x42a,0x482,0x4da,0x532,0x58a,0x5e2,0x63a,0x692,0x6ea,0x742,0x79a,0x7f2,0x84a,0x8a2,0x03e,0x096,0x0ee,0x146,0x19e,0x1f6,0x24e,0x2a6,0x2fe,0x356,0x3ae,0x406 },
	{ 0x70f,0x767,0x7bf,0x817,0x86f,0x00b,0x063,0x0bb,0x113,0x16b,0x1c3,0x21b,0x273,0x2cb,0x323,0x37b,0x3d3,0x42b,0x483,0x4db,0x533,0x58b,0x5e3,0x63b,0x693,0x6eb,0x743,0x79b,0x7f3,0x84b,0x8a3,0x03f,0x097,0x0ef,0x147,0x19f,0x1f7,0x24f,0x2a7,0x2ff,0x357,0x3af,0x407 },
	{ 0x764,0x7bc,0x814,0x86c,0x008,0x060,0x0b8,0x110,0x168,0x1c0,0x218,0x270,0x2c8,0x320,0x378,0x3d0,0x428,0x480,0x4d8,0x530,0x588,0x5e0,0x638,0x690,0x6e8,0x740,0x798,0x7f0,0x848,0x8a0,0x03c,0x094,0x0ec,0x144,0x19c,0x1f4,0x24c,0x2a4,0x2fc,0x354,0x3ac,0x404,0x45c },
	{ 0x765,0x7bd,0x815,0x86d,0x009,0x061,0x0b9,0x111,0x169,0x1c1,0x219,0x271,0x2c9,0x321,0x379,0x3d1,0x429,0x481,0x4d9,0x531,0x589,0x5e1,0x639,0x691,0x6e9,0x741,0x799,0x7f1,0x849,0x8a1,0x03d,0x095,0x0ed,0x145,0x19d,0x1f5,0x24d,0x2a5,0x2fd,0x355,0x3ad,0x405,0x45d },
	{ 0x7ba,0x812,0x86a,0x006,0x05e,0x0b6,0x10e,0x166,0x1be,0x216,0x26e,0x2c6,0x31e,0x376,0x3ce,0x426,0x47e,0x4d6,0x52e,0x586,0x5de,0x636,0x68e,0x6e6,0x73e,0x796,0x7ee,0x846,0x89e,0x03a,0x092,0x0ea,0x142,0x19a,0x1f2,0x24a,0x2a2,0x2fa,0x352,0x3aa,0x402,0x45a,0x4b2 },
	{ 0x7bb,0x813,0x86b,0x007,0x05f,0x0b7,0x10f,0x167,0x1bf,0x217,0x26f,0x2c7,0x31f,0x377,0x3cf,0x427,0x47f,0x4d7,0x52f,0x587,0x5df,0x637,0x68f,0x6e7,0x73f,0x797,0x7ef,0x847,0x89f,0x03b,0x093,0x0eb,0x143,0x19b,0x1f3,0x24b,0x2a3,0x2fb,0x353,0x3ab,0x403,0x45b,0x4b3 },
	{ 0x810,0x868,0x004,0x05c,0x0b4,0x10c,0x164,0x1bc,0x214,0x26c,0x2c4,0x31c,0x374,0x3cc,0x424,0x47c,0x4d4,0x52c,0x584,0x5dc,0x634,0x68c,0x6e4,0x73c,0x794,0x7ec,0x844,0x89c,0x038,0x090,0x0e8,0x140,0x198,0x1f0,0x248,0x2a0,0x2f8,0x350,0x3a8,0x400,0x458,0x4b0,0x508 },
	{ 0x811,0x869,0x005,0x05d,0x0b5,0x10d,0x165,0x1bd,0x215,0x26d,0x2c5,0x31d,0x375,0x3cd,0x425,0x47d,0x4d5,0x52d,0x585,0x5dd,0x635,0x68d,0x6e5,0x73d,0x795,0x7ed,0x845,0x89d,0x039,0x091,0x0e9,0x141,0x199,0x1f1,0x249,0x2a1,0x2f9,0x351,0x3a9,0x401,0x459,0x4b1,0x509 },
	{ 0x866,0x002,0x05a,0x0b2,0x10a,0x162,0x1ba,0x212,0x26a,0x2c2,0x31a,0x372,0x3ca,0x422,0x47a,0x4d2,0x52a,0x582,0x5da,0x632,0x68a,0x6e2,0x73a,0x792,0x7ea,0x842,0x89a,0x036,0x08e,0x0e6,0x13e,0x196,0x1ee,0x246,0x29e,0x2f6,0x34e,0x3a6,0x3fe,0x456,0x4ae,0x506,0x55e },
	{ 0x867,0x003,0x05b,0x0b3,0x10b,0x163,0x1bb,0x213,0x26b,0x2c3,0x31b,0x373,0x3cb,0x423,0x47b,0x4d3,0x52b,0x583,0x5db,0x633,0x68b,0x6e3,0x73b,0x793,0x7eb,0x843,0x89b,0x037,0x08f,0x0e7,0x13f,0x197,0x1ef,0x247,0x29f,0x2f7,0x34f,0x3a7,0x3ff,0x457,0x4af,0x507,0x55f }
};


//-------------------------------------------------
//  ecc_source_byte - return data from the sector
//  at the given offset, masking anything 
//  particular to a mode
//-------------------------------------------------

inline UINT8 ecc_source_byte(const UINT8 *sector, UINT32 offset)
{
	// in mode 2 always treat these as 0 bytes
	return (sector[MODE_OFFSET] == 2 && offset < 4) ? 0x00 : sector[SYNC_OFFSET + SYNC_NUM_BYTES + offset];
}


//-------------------------------------------------
//  ecc_compute_bytes - calculate an ECC value 
//  (P or Q)
//-------------------------------------------------

void ecc_compute_bytes(const UINT8 *sector, const UINT16 *row, int rowlen, UINT8 &val1, UINT8 &val2)
{
	val1 = val2 = 0;
	for (int component = 0; component < rowlen; component++)
	{
        val1 ^= ecc_source_byte(sector, row[component]);
        val2 ^= ecc_source_byte(sector, row[component]);
        val1 = ecclow[val1];
    }
    val1 = ecchigh[ecclow[val1] ^ val2];
	val2 ^= val1;
}


//-------------------------------------------------
//  ecc_verify - verify the P and Q ECC codes in
//  a sector
//-------------------------------------------------

bool ecc_verify(const UINT8 *sector)
{
	// first verify P bytes
	for (int byte = 0; byte < ECC_P_NUM_BYTES; byte++)
	{
		UINT8 val1, val2;
	    ecc_compute_bytes(sector, poffsets[byte], ECC_P_COMP, val1, val2);
		if (sector[ECC_P_OFFSET + byte] != val1 || sector[ECC_P_OFFSET + ECC_P_NUM_BYTES + byte] != val2)
			return false;
	}
	
	// then verify Q bytes
    for (int byte = 0; byte < ECC_Q_NUM_BYTES; byte++)
	{
		UINT8 val1, val2;
	    ecc_compute_bytes(sector, qoffsets[byte], ECC_Q_COMP, val1, val2);
		if (sector[ECC_Q_OFFSET + byte] != val1 || sector[ECC_Q_OFFSET + ECC_Q_NUM_BYTES + byte] != val2)
			return false;
	}
	return true;
}


//-------------------------------------------------
//  ecc_generate - generate the P and Q ECC codes 
//  for a sector, overwriting any existing codes
//-------------------------------------------------

void ecc_generate(UINT8 *sector)
{
	// first verify P bytes
	for (int byte = 0; byte < ECC_P_NUM_BYTES; byte++)
	    ecc_compute_bytes(sector, poffsets[byte], ECC_P_COMP, sector[ECC_P_OFFSET + byte], sector[ECC_P_OFFSET + ECC_P_NUM_BYTES + byte]);
	
	// then verify Q bytes
    for (int byte = 0; byte < ECC_Q_NUM_BYTES; byte++)
	    ecc_compute_bytes(sector, qoffsets[byte], ECC_Q_COMP, sector[ECC_Q_OFFSET + byte], sector[ECC_Q_OFFSET + ECC_Q_NUM_BYTES + byte]);
}


//-------------------------------------------------
//  ecc_clear - erase the ECC P and Q cods to 0
//	within a sector
//-------------------------------------------------

void ecc_clear(UINT8 *sector)
{
	memset(&sector[ECC_P_OFFSET], 0, 2 * ECC_P_NUM_BYTES);
	memset(&sector[ECC_Q_OFFSET], 0, 2 * ECC_Q_NUM_BYTES);
}