neser 1.1.0

NESER - Nintendo Emulation Systems Engine (Rust). Desktop and WebAssembly frontends.
Documentation 
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

/// Open-source DMG boot ROM replacement.
///
/// Mimics the visual and audio behavior of a real DMG boot sequence:
/// scrolling the Nintendo logo down from off-screen, playing the two-note
/// "ba-ding!" sound near the end of the scroll, then holding the logo
/// on screen before handing off to the cartridge.
///
/// Key behavioral properties matching real hardware:
///   - SCY starts at 100 ($64), scrolls 1 pixel per 2-VBlank iteration
///   - Sound triggers near end of scroll: NR13=$83 at iter 98, NR13=$C1 at iter 100
///   - 32-iteration hold phase (~64 frames) after scroll completes
///   - NR11=$80 (50% duty cycle) for authentic sound character
///   - VBlank detection via LY polling (LDH A,[$FF44]; CP 144)
///   - Logo is accepted without verification (custom ROM design choice)
///
/// ## ROM layout
///
/// | Address   | Content                                    | Size  |
/// |-----------|--------------------------------------------|-------|
/// | $0000     | SP init + VRAM clear                       | 12 B  |
/// | $000C     | APU init (no trigger) + NR11 duty          | 16 B  |
/// | $001C     | BGP = $FC                                  | 4 B   |
/// | $0020     | Logo tile load (CALL $00A7)                | 20 B  |
/// | $0034     | Tile map setup                             | 18 B  |
/// | $0046     | Pre-LCD delay (N=2148, 2 NOP)              | 10 B  |
/// | $0050     | LCD enable (LCDC=$91)                      | 4 B   |
/// | $0054     | SCY = $64 (100)                            | 4 B   |
/// | $0058     | Scroll loop setup (D=100, B=1, H=0)        | 4 B   |
/// | $005C     | Scroll loop (LY poll + sound + SCY update) | 56 B  |
/// | $0094     | Padding                                    | 19 B  |
/// | $00A7     | `DoubleBitsAndWriteRow`                    | 21 B  |
/// | $00BC     | Post-loop: IF=$E1, DIV fine-tune, regs     | 34 B  |
/// | $00DE     | Padding                                    | 32 B  |
/// | $00FE     | `BootGame` (LDH [$FF50])                   | 2 B   |
pub const DMG_BOOT_ROM: [u8; 256] = [
    // ── $0000: LD SP, $FFFE ──────────────────────────────────────────────────
    0x31, 0xFE, 0xFF,
    // ── $0003: Clear VRAM ($8000–$9FFF) ─────────────────────────────────────
    0x21, 0x00, 0x80, 0xAF, 0x22, 0xCB, 0x6C, 0x28, 0xFB,
    // ── $000C: APU init — envelope/panning/volume only, NO trigger ───────────
    0x3E, 0x80, 0xE0, 0x26, // LD A,$80; LDH [$FF26]  NR52 (APU on)
    0xE0, 0x11, // LDH [$FF11]             NR11=$80 (50% duty)
    0x3E, 0xF3, 0xE0, 0x12, // LD A,$F3; LDH [$FF12]  NR12 (envelope)
    0xE0, 0x25, // LDH [$FF25]             NR51=$F3 (panning)
    0x3E, 0x77, 0xE0, 0x24, // LD A,$77; LDH [$FF24]  NR50 (volume)
    // ── $001C: Init BG palette ───────────────────────────────────────────────
    0x3E, 0xFC, 0xE0, 0x47, // LD A,$FC; LDH [$FF47]  BGP
    // ── $0020: Load logo tiles from cartridge header → VRAM ──────────────────
    0x11, 0x04, 0x01, // LD DE, $0104
    0x21, 0x10, 0x80, // LD HL, $8010
    // .logoLoop ($0026):
    0x1A, 0x47, // LD A,[DE]; LD B,A
    0xCD, 0xA7, 0x00, // CALL DoubleBitsAndWriteRow ($00A7)
    0xCD, 0xA7, 0x00, // CALL DoubleBitsAndWriteRow ($00A7)
    0x13, // INC DE
    0x7B, 0xEE, 0x34, // LD A,E; XOR $34
    0x20, 0xF2, // JR NZ, .logoLoop (→ $0026)
    // ── $0034: Build BG tile map ─────────────────────────────────────────────
    0x3E, 0x19, // LD A, $19
    0x21, 0x2F, 0x99, // LD HL, $992F
    0x0E, 0x0C, // LD C, 12
    // .tmapLoop ($003B):
    0x3D, // DEC A
    0x28, 0x08, // JR Z, .tmapDone (+8 → $0046)
    0x32, // LD [HL-], A
    0x0D, // DEC C
    0x20, 0xF9, // JR NZ, .tmapLoop (→ $003B)
    0x2E, 0x0F, // LD L, $0F
    0x18, 0xF5, // JR .tmapLoop (→ $003B)
    // .tmapDone ($0046):
    // ── $0046: Pre-LCD delay (tuned for DIV=$AB alignment) ───────────────────
    0x21, 0x64, 0x08, // LD HL, $0864  (2148)
    0x00, 0x00, // 2 × NOP
    // .preLoop ($004B):
    0x2B, 0x7C, 0xB5, 0x20, 0xFB, // DEC HL; LD A,H; OR L; JR NZ
    // ── $0050: Enable LCD ────────────────────────────────────────────────────
    0x3E, 0x91, 0xE0, 0x40, // LD A,$91; LDH [$FF40]
    // ── $0054: SCY = $64 (100 pixels) ────────────────────────────────────────
    0x3E, 0x64, 0xE0, 0x42, // LD A,$64; LDH [$FF42]
    // ── $0058: Scroll loop register setup ────────────────────────────────────
    0x57, // LD D, A       D = 100 (iteration counter)
    0x04, // INC B         B = 1 (scroll active flag)
    0x26, 0x00, // LD H, 0      H = 0 (frame counter for sound)
    // ═══════════════════════════════════════════════════════════════════════
    // ── $005C: Main scroll/hold loop (LY-polling, VBlank-synced) ─────────
    // ═══════════════════════════════════════════════════════════════════════
    // .loop ($005C):
    0x1E, 0x02, // LD E, 2      E = 2 VBlanks per iteration
    // .waitNotVblank ($005E):  — wait until LY < 144
    0xF0, 0x44, // LDH A, [$FF44]
    0xFE, 0x90, // CP 144
    0x30, 0xFA, // JR NC, .waitNotVblank (→ $005E)
    // .waitVblank ($0064):  — wait until LY ≥ 144
    0xF0, 0x44, // LDH A, [$FF44]
    0xFE, 0x90, // CP 144
    0x38, 0xFA, // JR C, .waitVblank (→ $0064)
    // VBlank entered:
    0x1D, // DEC E
    0x20, 0xF1, // JR NZ, .waitNotVblank (→ $005E)
    // ── $006D: Sound trigger check ───────────────────────────────────────────
    0x24, // INC H         frame counter++
    0x7C, // LD A, H
    0x0E, 0x13, // LD C, $13     C = LOW(rNR13)
    0x1E, 0x83, // LD E, $83     first note frequency
    0xFE, 0x62, // CP $62        iteration 98?
    0x28, 0x06, // JR Z, .playSound (→ $007D)
    0x1E, 0xC1, // LD E, $C1     second note frequency
    0xFE, 0x64, // CP $64        iteration 100?
    0x20, 0x08, // JR NZ, .noSound (→ $0085)
    // .playSound ($007D):
    0x7B, // LD A, E
    0xE2, // LD ($FF00+C), A  → NR13
    0x0C, // INC C            → C = $14
    0x3E, 0x87, // LD A, $87
    0xE2, // LD ($FF00+C), A  → NR14 (trigger + freq high=$07)
    0x18, 0x00, // JR .noSound (→ $0085)
    // .noSound ($0085):
    0xF0, 0x42, // LDH A, [$FF42]   read SCY
    0x90, // SUB B             SCY -= B (1 if scroll, 0 if hold)
    0xE0, 0x42, // LDH [$FF42], A   write SCY
    // ── $008A: Loop control ──────────────────────────────────────────────────
    0x15, // DEC D
    0x20, 0xCF, // JR NZ, .loop (→ $005C)
    0x05, // DEC B        B: 1→0 (enter hold) or 0→$FF (exit)
    0x20, 0x2C, // JR NZ, .done (→ $00BC)
    0x16, 0x20, // LD D, 32     hold phase: 32 iterations
    0x18, 0xC8, // JR .loop (→ $005C)
    // ── $0094–$00A6: Padding ─────────────────────────────────────────────────
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00,
    // ════════════════════════════════════════════════════════════════════════
    // ── $00A7: DoubleBitsAndWriteRow ─────────────────────────────────────────
    0x3E, 0x04, // LD A, 4
    0x0E, 0x00, // LD C, 0
    // .dblLoop ($00AB):
    0xCB, 0x20, // SLA B
    0xF5, // PUSH AF
    0xCB, 0x11, // RL C
    0xF1, // POP AF
    0xCB, 0x11, // RL C
    0x3D, // DEC A
    0x20, 0xF5, // JR NZ, .dblLoop (→ $00AB)
    0x79, // LD A, C
    0x22, 0x23, // LD [HL+],A; INC HL
    0x22, 0x23, // LD [HL+],A; INC HL
    0xC9, // RET
    // ════════════════════════════════════════════════════════════════════════
    // ── $00BC: .done — post-loop continuation ────────────────────────────────
    0x3E, 0xE1, 0xE0, 0x0F, // LD A,$E1; LDH [$FF0F]   IF = $E1
    // ── $00C0: Fine-tune delay (calibrated for DIV=$AB + LY=$0A at exit) ────
    0x21, 0xB4, 0xEB, // LD HL, $EBB4 (N=60340)
    0x00, 0x00, 0x00, // 3 × NOP
    // .fineLoop ($00C6):
    0x2B, 0x7C, 0xB5, 0x20, 0xFB, // DEC HL; LD A,H; OR L; JR NZ
    // ── $00CB: Set post-boot register state ──────────────────────────────────
    0x21, 0xB0, 0x01, // LD HL, $01B0
    0xE5, 0xF1, // PUSH HL; POP AF  → AF=$01B0
    0x21, 0x4D, 0x01, // LD HL, $014D
    0x01, 0x13, 0x00, // LD BC, $0013
    0x11, 0xD8, 0x00, // LD DE, $00D8
    // ── $00D9: JP BootGame ($00FE) ───────────────────────────────────────────
    0xC3, 0xFE, 0x00,
    // ── $00DC–$00FD: Padding ─────────────────────────────────────────────────
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00,
    // ════════════════════════════════════════════════════════════════════════
    // ── $00FE: BootGame ──────────────────────────────────────────────────────
    0xE0, 0x50, // LDH [$FF50], A  (unmap boot ROM → execute $0100)
];

/// Open-source DMG-0 (first production run) boot ROM replacement.
///
/// DMG-0 had a simpler boot ROM than later DMG revisions: no logo scroll
/// animation, no header verification. This replacement reproduces the exact
/// post-boot hardware state expected by the Mooneye `boot_hwio-dmg0` and
/// `boot_div-dmg0` acceptance tests, including the "ba-ding!" boot sound
/// (CH1 triggered via NR13/NR14).
///
/// ## Post-boot state produced
///
/// | Register | Value |    | I/O       | Value |
/// |----------|-------|----|-----------|-------|
/// | A        | $01   |    | DIV       | $18   |
/// | F        | $00   |    | LCDC      | $91   |
/// | B        | $FF   |    | BGP       | $FC   |
/// | C        | $13   |    | NR52      | $F1   |
/// | D        | $00   |    |           |       |
/// | E        | $C1   |    |           |       |
/// | H        | $84   |    |           |       |
/// | L        | $03   |    |           |       |
/// | SP       | $FFFE |    |           |       |
///
/// ## Timing
///
/// Total M-cycles: **17880** (≡ 1496 mod 16384, so DIV phase matches).
/// With `div_counter` initial value 204:
///   `204 + 17880 × 4 = 71724` → `71724 mod 65536 = 6188` → DIV = $18.
///
/// The `boot_div-dmg0` test first reads DIV 53 M-cycles after `$0100`:
///   `6188 + 53 × 4 = 6400 = $1900` → read returns $19 ✓.
///
/// LCD is enabled (`LCDC=$91`) at M-cycle 1322. The PPU runs for
/// 16558 M-cycles = 66232 T-cycles before boot exit, placing it in VBlank
/// (LY≈145). During the `boot_hwio` test's comparison loop the PPU
/// completes its first frame (70220 T, first scanline = 452 T), and by the
/// time the test reads `$FF41`/`$FF44` the PPU has wrapped into mode 3
/// of line 1, yielding STAT=$83 and LY=$01 as expected.
///
/// ## ROM layout
///
/// | Address | Content                                | M-cycles |
/// |---------|----------------------------------------|----------|
/// | $0000   | LD SP / APU init + sound / BGP         | 39       |
/// | $001F   | Pre-LCD delay loop (HL counter = 182)  | 1276     |
/// | $0027   | 2 × NOP (fine-tune timing)             | 2        |
/// | $0029   | Enable LCD (LCDC = $91)                | 5        |
/// | $002D   | Post-LCD delay loop (HL = 2362)        | 16536    |
/// | $0035   | 3 × NOP (fine-tune timing)             | 3        |
/// | $0038   | Set post-boot CPU registers            | 12       |
/// | $0044   | JP $00FE                               | 4        |
/// | $00FE   | LDH [$FF50], A (unmap boot ROM)        | 3        |
/// |         | **Total**                              | **17880**|
pub const DMG0_BOOT_ROM: [u8; 256] = [
    // ── $0000: LD SP, $FFFE ──────────────────────────────────────────────────
    0x31, 0xFE, 0xFF,
    // ── $0003: APU init + boot sound ─────────────────────────────────────────
    0x3E, 0x80, 0xE0, 0x26, // LD A,$80; LDH ($26),A  → NR52 = $80 (APU on)
    0xE0, 0x11, // LDH ($11),A            → NR11 = $80 (50% duty)
    0x3E, 0xF3, 0xE0, 0x12, // LD A,$F3; LDH ($12),A → NR12 = $F3 (envelope)
    0xE0, 0x25, // LDH ($25),A            → NR51 = $F3 (panning)
    0x3E, 0x77, 0xE0, 0x24, // LD A,$77; LDH ($24),A → NR50 = $77 (volume)
    0x3E, 0x83, 0xE0, 0x13, // LD A,$83; LDH ($13),A → NR13 = $83 (freq low)
    0x3E, 0x87, 0xE0, 0x14, // LD A,$87; LDH ($14),A → NR14 = $87 (trigger!)
    // ── $001B: BGP = $FC ─────────────────────────────────────────────────────
    0x3E, 0xFC, 0xE0, 0x47,
    // ── $001F: Pre-LCD delay loop (182 iterations × 7 M-cycles + overhead) ──
    // LD HL, 182  ($00B6)
    0x21, 0xB6, 0x00,
    // Loop: DEC HL; LD A,H; OR L; JR NZ → $0022  (7 M taken / 6 M last)
    0x2B, 0x7C, 0xB5, 0x20, 0xFB,
    // ── $0027: Fine-tune NOPs (2 × 1 M-cycle) ──────────────────────────────
    0x00, 0x00,
    // ── $0029: Enable LCD ────────────────────────────────────────────────────
    // LD A, $91  (LCDC: LCD on, BG on, BG tile data $8000, BG map $9800)
    0x3E, 0x91, // LDH ($FF40), A  — write LCDC; PPU begins at M-cycle 1322
    0xE0, 0x40,
    // ── $002D: Post-LCD delay loop (2362 iterations × 7 M-cycles + overhead)─
    // LD HL, 2362  ($093A)
    0x21, 0x3A, 0x09,
    // Loop: DEC HL; LD A,H; OR L; JR NZ → $0030  (7 M taken / 6 M last)
    0x2B, 0x7C, 0xB5, 0x20, 0xFB,
    // ── $0035: Fine-tune NOPs (3 × 1 M-cycle) ──────────────────────────────
    0x00, 0x00, 0x00,
    // ── $0038: Set post-boot CPU registers ───────────────────────────────────
    0x01, 0x13, 0xFF, // LD BC, $FF13  →  B=$FF, C=$13
    0x11, 0xC1, 0x00, // LD DE, $00C1  →  D=$00, E=$C1
    0x21, 0x03, 0x84, // LD HL, $8403  →  H=$84, L=$03
    0x3E, 0x01, // LD A, $01
    0xB7, // OR A          →  F=$00 (Z=0, N=0, H=0, C=0)
    // ── $0044: Jump to boot exit at $00FE ───────────────────────────────────
    0xC3, 0xFE, 0x00, // JP $00FE
    // ── $0047–$00FD: Unused (fill with $00) ─────────────────────────────────
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // $0047–$004E
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // $004F–$0056
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // $0057–$005E
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // $005F–$0066
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // $0067–$006E
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // $006F–$0076
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // $0077–$007E
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // $007F–$0086
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // $0087–$008E
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // $008F–$0096
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // $0097–$009E
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // $009F–$00A6
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // $00A7–$00AE
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // $00AF–$00B6
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // $00B7–$00BE
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // $00BF–$00C6
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // $00C7–$00CE
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // $00CF–$00D6
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // $00D7–$00DE
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // $00DF–$00E6
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // $00E7–$00EE
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // $00EF–$00F6
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // $00F7–$00FD
    // ── $00FE: BootGame ──────────────────────────────────────────────────────
    // Placed at $00FE so that PC = $0100 after the instruction executes,
    // which is the standard cartridge entry point.
    0xE0, 0x50, // LDH [$FF50], A  (unmap boot ROM → execute $0100)
];

/// Full CGB boot ROM with animation and sound.
///
/// This IPR-free implementation provides:
/// - VRAM/OAM clearing
/// - Wave RAM initialization (alternating 0x00/0xFF pattern)
/// - Logo decompression from cartridge header ($0104-$0133)
/// - Boot chime (two tones at ~988 Hz and ~1319 Hz)
/// - CGB palette initialization
/// - DMG compatibility mode detection (reads $0143, sets KEY0/OPRI)
/// - DMG compatibility palette selection (automatic + manual override)
/// - Proper CPU register setup for cartridge handoff
///
/// ## DMG Compatibility Mode
///
/// The boot ROM reads the CGB flag at $0143 and configures hardware:
/// - **CGB-compatible** (bit 7 set): KEY0 = CGB flag, OPRI = $00
/// - **DMG-only** (bit 7 clear): KEY0 = $04, OPRI = $01
///
/// For DMG-only games, a colorization palette is applied at boot exit:
/// - **Automatic**: Selected based on ROM title checksum (like real CGB)
/// - **Manual override**: User can hold button combinations to select palette:
///   - Up: palette 5, Up+A: 43, Up+B: 28
///   - Down: palette 8, Down+A: 3, Down+B: 49
///   - Left: palette 48, Left+A: 40, Left+B: 7
///   - Right: palette 1, Right+A: 0, Right+B: 6
///
/// ## Post-boot CPU state
///
/// | Register | Value |
/// |----------|-------|
/// | A        | $11   |
/// | F        | $80 (Z=1, N=0, H=0, C=0) |
/// | B        | $00   |
/// | C        | $00   |
/// | D        | $00   |
/// | E        | $08   |
/// | H        | $00   |
/// | L        | $7C   |
/// | SP       | $FFFE |
/// | PC       | $0100 |
///
/// ## Memory layout
///
/// The CGB boot ROM is 2048 bytes, split into two mapped regions:
/// - $0000-$00FF: Early initialization (256 bytes) → array indices [0..256]
/// - $0100-$01FF: Cartridge header (NOT in boot ROM; reads go to cartridge)
/// - $0200-$08FF: Subroutines and data (1792 bytes) → array indices [256..2048]
pub const CGB_BOOT_ROM: [u8; 2048] = [
    0x31, 0xFE, 0xFF, 0x21, 0x00, 0x80, 0xAF, 0x22, 0xCB, 0x6C, 0x28, 0xFA, 0x26, 0xFE, 0x0E,
    0xA0, // $0000
    0x22, 0x0D, 0x20, 0xFC, 0x0E, 0x10, 0x21, 0x30, 0xFF, 0x22, 0x2F, 0x0D, 0x20, 0xFB, 0xAF,
    0xE0, // $0010
    0x80, 0xE0, 0x81, 0x3E, 0x80, 0xE0, 0x26, 0xE0, 0x11, 0x3E, 0xF3, 0xE0, 0x12, 0xE0, 0x25,
    0x3E, // $0020
    0x77, 0xE0, 0x24, 0x3E, 0xFC, 0xE0, 0x47, 0x11, 0x04, 0x01, 0x21, 0x10, 0x80, 0x1A, 0x47,
    0xCD, // $0030
    0x00, 0x02, 0x13, 0x7B, 0xFE, 0x34, 0x20, 0xF5, 0x3E, 0x80, 0xE0, 0x68, 0x0E, 0x40, 0x21,
    0x80, // $0040
    0x02, 0x2A, 0xE0, 0x69, 0x0D, 0x20, 0xFA, 0x3E, 0x91, 0xE0, 0x40, 0x06, 0x3C, 0xCD, 0x40,
    0x02, // $0050
    0x05, 0x20, 0xFA, 0x3E, 0x83, 0xE0, 0x13, 0x3E, 0x87, 0xE0, 0x14, 0x06, 0x05, 0xCD, 0x40,
    0x02, // $0060
    0x05, 0x20, 0xFA, 0x3E, 0xC1, 0xE0, 0x13, 0x3E, 0x87, 0xE0, 0x14, 0x06, 0x1E, 0xCD, 0x40,
    0x02, // $0070
    // ── $0073: DMG compatibility mode detection ────────────────────────────────
    // Read CGB flag from cartridge header at $0143, test bit 7.
    // Bit 7 set → CGB-compatible: write CGB flag to KEY0 ($FF4C), OPRI stays $00.
    // Bit 7 clear → DMG-only: write $04 to KEY0, $01 to OPRI ($FF6C).
    0x05, 0x20, 0xFA, // DEC B; JR NZ, -6 (end of sound loop)
    0xFA, 0x43, 0x01, // LD A, [$0143] - read CGB flag
    0xCB, 0x7F, // BIT 7, A - test bit 7
    0x20, 0x0C, // JR NZ, +12 (→ $0086 .cgb_mode)
    // .dmg_mode:
    0x3E, 0x04, // LD A, $04
    0xE0, 0x4C, // LDH [$4C], A - KEY0 = $04 (DMG compat mode)
    0x3E, // $0080
    0x01, // LD A, $01
    0xE0, 0x6C, // LDH [$6C], A - OPRI = $01 (DMG OBJ priority)
    0x18, 0x07, // JR +7 (→ $008B .setup_regs)
    0x00, 0x00, // (padding)
    // .cgb_mode:
    0xFA, 0x43, 0x01, // LD A, [$0143] - re-read CGB flag
    0xE0, 0x4C, // LDH [$4C], A - KEY0 = CGB flag
    // .setup_regs:
    0x26, 0x11, // LD H, $11
    0x2E, 0x80, 0xE5, // $0090
    0xF1, // POP AF (A=$11, F=$80)
    0x01, 0x00, 0x00, // LD BC, $0000
    0x11, 0x08, 0x00, // LD DE, $0008
    0x21, 0x7C, 0x00, // LD HL, $007C
    0xC3, 0xFE, 0x00, // JP $00FE
    0x00, 0x00, 0x00, // $00A0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $00B0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $00C0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $00D0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $00E0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xE0,
    0x50, // $00F0
    0xCD, 0x03, 0x02, 0x3E, 0x04, 0x0E, 0x00, 0xCB, 0x20, 0xF5, 0xCB, 0x11, 0xF1, 0xCB, 0x11,
    0x3D, // $0200
    0x20, 0xF5, 0x79, 0x22, 0x23, 0x22, 0x23, 0xC9, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0210
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0220
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0230
    0xE5, 0x21, 0x0F, 0xFF, 0xCB, 0x86, 0xCB, 0x46, 0x28, 0xFC, 0xE1, 0xC9, 0x00, 0x00, 0x00,
    0x00, // $0240
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0250
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0260
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0270
    0xFF, 0x7F, 0x94, 0x52, 0x4A, 0x29, 0x00, 0x00, 0xFF, 0x7F, 0x94, 0x52, 0x4A, 0x29, 0x00,
    0x00, // $0280
    0xFF, 0x7F, 0x94, 0x52, 0x4A, 0x29, 0x00, 0x00, 0xFF, 0x7F, 0x94, 0x52, 0x4A, 0x29, 0x00,
    0x00, // $0290
    0xFF, 0x7F, 0x94, 0x52, 0x4A, 0x29, 0x00, 0x00, 0xFF, 0x7F, 0x94, 0x52, 0x4A, 0x29, 0x00,
    0x00, // $02A0
    0xFF, 0x7F, 0x94, 0x52, 0x4A, 0x29, 0x00, 0x00, 0xFF, 0x7F, 0x94, 0x52, 0x4A, 0x29, 0x00,
    0x00, // $02B0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $02C0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $02D0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $02E0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $02F0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0300
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0310
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0320
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0330
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0340
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0350
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0360
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0370
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0380
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0390
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $03A0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $03B0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $03C0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $03D0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $03E0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $03F0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0400
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0410
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0420
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0430
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0440
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0450
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0460
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0470
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0480
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0490
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $04A0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $04B0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $04C0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $04D0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $04E0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $04F0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0500
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0510
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0520
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0530
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0540
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0550
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0560
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0570
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0580
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0590
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $05A0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $05B0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $05C0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $05D0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $05E0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $05F0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0600
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0610
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0620
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0630
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0640
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0650
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0660
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0670
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0680
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0690
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $06A0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $06B0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $06C0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $06D0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $06E0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $06F0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0700
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0710
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0720
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0730
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0740
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0750
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0760
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0770
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0780
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0790
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $07A0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $07B0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $07C0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $07D0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $07E0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $07F0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0800
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0810
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0820
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0830
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0840
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0850
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0860
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0870
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0880
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0890
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $08A0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $08B0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $08C0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $08D0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $08E0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $08F0
];

/// CGB boot ROM for CGB-0 (first hardware revision).
///
/// CGB-0 is a rare early CGB revision with a slightly different boot ROM.
/// The key difference: CGB-0 does NOT initialize wave RAM ($FF30-$FF3F),
/// leaving it unchanged in its power-on state.
///
/// All other aspects are identical to the Production CGB boot ROM, including
/// DMG compatibility mode detection.
///
/// ## DMG Compatibility Mode
///
/// The boot ROM reads the CGB flag at $0143 and configures hardware:
/// - **CGB-compatible** (bit 7 set): KEY0 = CGB flag, OPRI = $00
/// - **DMG-only** (bit 7 clear): KEY0 = $04, OPRI = $01
///
/// ## Post-boot CPU state (same as Production CGB)
///
/// | Register | Value |
/// |----------|-------|
/// | A        | $11   |
/// | F        | $80 (Z=1, N=0, H=0, C=0) |
/// | B        | $00   |
/// | C        | $00   |
/// | D        | $00   |
/// | E        | $08   |
/// | H        | $00   |
/// | L        | $7C   |
/// | SP       | $FFFE |
/// | PC       | $0100 |
pub const CGB0_BOOT_ROM: [u8; 2048] = [
    0x31, 0xFE, 0xFF, 0x21, 0x00, 0x80, 0xAF, 0x22, 0xCB, 0x6C, 0x28, 0xFA, 0x26, 0xFE, 0x0E,
    0xA0, // $0000
    0x22, 0x0D, 0x20, 0xFC, 0xAF, 0xE0, 0x80, 0xE0, 0x81, 0x3E, 0x80, 0xE0, 0x26, 0xE0, 0x11,
    0x3E, // $0010
    0xF3, 0xE0, 0x12, 0xE0, 0x25, 0x3E, 0x77, 0xE0, 0x24, 0x3E, 0xFC, 0xE0, 0x47, 0x11, 0x04,
    0x01, // $0020
    0x21, 0x10, 0x80, 0x1A, 0x47, 0xCD, 0x00, 0x02, 0x13, 0x7B, 0xFE, 0x34, 0x20, 0xF5, 0x3E,
    0x80, // $0030
    0xE0, 0x68, 0x0E, 0x40, 0x21, 0x80, 0x02, 0x2A, 0xE0, 0x69, 0x0D, 0x20, 0xFA, 0x3E, 0x91,
    0xE0, // $0040
    0x40, 0x06, 0x3C, 0xCD, 0x40, 0x02, 0x05, 0x20, 0xFA, 0x3E, 0x83, 0xE0, 0x13, 0x3E, 0x87,
    0xE0, // $0050
    0x14, 0x06, 0x05, 0xCD, 0x40, 0x02, 0x05, 0x20, 0xFA, 0x3E, 0xC1, 0xE0, 0x13, 0x3E, 0x87,
    0xE0, // $0060
    // ── $0069: DMG compatibility mode detection (CGB-0) ────────────────────────
    // Same logic as Production CGB, just at different offset due to no wave RAM init.
    0x14, 0x06, 0x1E, 0xCD, 0x40, 0x02, 0x05, 0x20, 0xFA, // sound loop end
    0xFA, 0x43, 0x01, // LD A, [$0143] - read CGB flag
    0xCB, 0x7F, // BIT 7, A - test bit 7
    0x20, // $0070
    0x0C, // JR NZ, +12 (→ $007C .cgb_mode)
    // .dmg_mode:
    0x3E, 0x04, // LD A, $04
    0xE0, 0x4C, // LDH [$4C], A - KEY0 = $04 (DMG compat mode)
    0x3E, 0x01, // LD A, $01
    0xE0, 0x6C, // LDH [$6C], A - OPRI = $01 (DMG OBJ priority)
    0x18, 0x07, // JR +7 (→ $0081 .setup_regs)
    0x00, 0x00, // (padding)
    // .cgb_mode:
    0xFA, 0x43, 0x01, // LD A, [$0143] - re-read CGB flag
    0xE0, // $0080
    0x4C, // LDH [$4C], A - KEY0 = CGB flag
    // .setup_regs:
    0x26, 0x11, // LD H, $11
    0x2E, 0x80, // LD L, $80
    0xE5, // PUSH HL
    0xF1, // POP AF (A=$11, F=$80)
    0x01, 0x00, 0x00, // LD BC, $0000
    0x11, 0x08, 0x00, // LD DE, $0008
    0x21, 0x7C, 0x00, // LD HL, $007C
    0xC3, // $0090
    0xFE, 0x00, // JP $00FE
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // $00A0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $00B0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $00C0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $00D0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $00E0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xE0,
    0x50, // $00F0
    0xCD, 0x03, 0x02, 0x3E, 0x04, 0x0E, 0x00, 0xCB, 0x20, 0xF5, 0xCB, 0x11, 0xF1, 0xCB, 0x11,
    0x3D, // $0200
    0x20, 0xF5, 0x79, 0x22, 0x23, 0x22, 0x23, 0xC9, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0210
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0220
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0230
    0xE5, 0x21, 0x0F, 0xFF, 0xCB, 0x86, 0xCB, 0x46, 0x28, 0xFC, 0xE1, 0xC9, 0x00, 0x00, 0x00,
    0x00, // $0240
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0250
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0260
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0270
    0xFF, 0x7F, 0x94, 0x52, 0x4A, 0x29, 0x00, 0x00, 0xFF, 0x7F, 0x94, 0x52, 0x4A, 0x29, 0x00,
    0x00, // $0280
    0xFF, 0x7F, 0x94, 0x52, 0x4A, 0x29, 0x00, 0x00, 0xFF, 0x7F, 0x94, 0x52, 0x4A, 0x29, 0x00,
    0x00, // $0290
    0xFF, 0x7F, 0x94, 0x52, 0x4A, 0x29, 0x00, 0x00, 0xFF, 0x7F, 0x94, 0x52, 0x4A, 0x29, 0x00,
    0x00, // $02A0
    0xFF, 0x7F, 0x94, 0x52, 0x4A, 0x29, 0x00, 0x00, 0xFF, 0x7F, 0x94, 0x52, 0x4A, 0x29, 0x00,
    0x00, // $02B0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $02C0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $02D0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $02E0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $02F0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0300
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0310
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0320
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0330
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0340
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0350
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0360
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0370
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0380
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0390
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $03A0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $03B0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $03C0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $03D0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $03E0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $03F0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0400
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0410
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0420
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0430
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0440
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0450
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0460
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0470
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0480
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0490
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $04A0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $04B0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $04C0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $04D0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $04E0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $04F0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0500
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0510
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0520
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0530
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0540
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0550
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0560
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0570
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0580
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0590
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $05A0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $05B0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $05C0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $05D0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $05E0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $05F0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0600
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0610
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0620
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0630
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0640
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0650
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0660
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0670
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0680
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0690
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $06A0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $06B0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $06C0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $06D0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $06E0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $06F0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0700
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0710
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0720
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0730
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0740
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0750
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0760
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0770
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0780
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0790
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $07A0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $07B0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $07C0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $07D0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $07E0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $07F0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0800
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0810
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0820
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0830
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0840
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0850
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0860
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0870
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0880
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $0890
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $08A0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $08B0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $08C0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $08D0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $08E0
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, // $08F0
];

/// Placeholder CGB boot ROM for infrastructure testing.
///
/// This is a minimal boot ROM that immediately disables itself and jumps to
/// the cartridge entry point at $0100. It is used during infrastructure
/// development and will be replaced by a full IPR-free CGB boot ROM implementation.
///
/// The CGB boot ROM is 2048 bytes, split into two mapped regions:
/// - $0000-$00FF: Early initialization (256 bytes)
/// - $0100-$01FF: Cartridge header (not part of the boot ROM; reads come from the cartridge)
/// - $0200-$08FF: Main boot ROM code (1792 bytes)
///
/// In this array, the boot-ROM-backed regions are stored contiguously:
/// indices 0..256 correspond to $0000-$00FF, and indices 256..2048
/// correspond to $0200-$08FF. The $0100-$01FF header gap exists in the
/// memory map, not as a gap inside this array.
///
/// This placeholder contains code to disable the boot ROM by writing to $FF50,
/// then jumping to $0100, followed by zero padding.
pub const CGB_PLACEHOLDER_BOOT_ROM: [u8; 2048] = {
    let mut rom = [0u8; 2048];
    // $0000: LD A, $01
    rom[0] = 0x3E; // LD A, n8
    rom[1] = 0x01; // value $01
    // $0002: LDH [$FF50], A  (unmap boot ROM)
    rom[2] = 0xE0; // LDH [n8], A
    rom[3] = 0x50; // $FF50
    // $0004: JP $0100  (jump to cartridge entry point)
    rom[4] = 0xC3; // JP opcode
    rom[5] = 0x00; // low byte of $0100
    rom[6] = 0x01; // high byte of $0100
    // Rest is padding (zeros)
    rom
};

#[cfg(test)]
mod tests {
    use super::DMG_BOOT_ROM;

    const CANONICAL_NINTENDO_LOGO_CRC32: u32 = 0x4619_5417;

    fn crc32(bytes: &[u8]) -> u32 {
        let mut crc = 0xFFFF_FFFFu32;
        for &byte in bytes {
            crc ^= u32::from(byte);
            for _ in 0..8 {
                let mask = (crc & 1).wrapping_neg() & 0xEDB8_8320;
                crc = (crc >> 1) ^ mask;
            }
        }
        !crc
    }

    #[test]
    fn dmg_boot_rom_sets_nr11_duty_cycle() {
        // Real hardware sets NR11=$80 (50% duty) for correct boot sound
        // character. The boot ROM must write $80 to $FF11 before the sound
        // is triggered. Look for LDH [$FF11],A right after writing NR52=$80
        // (which leaves A=$80), so we expect E0 11 at $0010.
        assert_eq!(DMG_BOOT_ROM[0x10], 0xE0, "NR11 write: LDH opcode expected");
        assert_eq!(
            DMG_BOOT_ROM[0x11], 0x11,
            "NR11 write: address byte $11 expected"
        );
    }

    #[test]
    fn dmg_boot_rom_does_not_trigger_sound_at_boot_start() {
        // Real hardware triggers the "ba-ding!" near the END of the scroll,
        // not at boot start. The APU init section ($000C–$001D) must set up
        // envelope/panning/volume but NOT write NR13/NR14 trigger.
        // Scan $000C–$001D for NR14 trigger byte ($87):
        let apu_init = &DMG_BOOT_ROM[0x0C..=0x1D];
        assert!(
            !apu_init.windows(2).any(|w| w == [0xE0, 0x14]),
            "NR14 trigger (LDH [$FF14]) must not appear in APU init section"
        );
        assert!(
            !apu_init.windows(2).any(|w| w == [0xE0, 0x13]),
            "NR13 freq (LDH [$FF13]) must not appear in APU init section"
        );
    }

    #[test]
    fn dmg_boot_rom_scroll_starts_at_100() {
        // Real hardware scrolls 100 pixels (SCY starts at $64).
        // Find LD A,$64; LDH [$FF42] pattern (3E 64 E0 42) somewhere
        // after the LCD enable section.
        let rom = &DMG_BOOT_ROM[0x50..0xA7];
        assert!(
            rom.windows(4).any(|w| w == [0x3E, 0x64, 0xE0, 0x42]),
            "SCY must be initialized to $64 (100) for real-hardware scroll distance"
        );
    }

    #[test]
    fn dmg_boot_rom_has_two_note_bading_sound() {
        // Real hardware plays two notes: NR13=$83 at scroll iter 98 and
        // NR13=$C1 at scroll iter 100. The ROM must contain both frequency
        // values as immediates within the scroll section ($005A–$00FD).
        let scroll_section = &DMG_BOOT_ROM[0x5A..0xFE];

        // First note frequency: $83
        assert!(
            scroll_section.contains(&0x83),
            "first 'ba' note frequency $83 must be in scroll section"
        );
        // Second note frequency: $C1
        assert!(
            scroll_section.contains(&0xC1),
            "second 'ding' note frequency $C1 must be in scroll section"
        );
        // Both iteration thresholds: $62 and $64
        assert!(
            scroll_section.contains(&0x62),
            "first sound trigger threshold $62 (iter 98) must be in scroll section"
        );
        assert!(
            scroll_section.contains(&0x64),
            "second sound trigger threshold $64 (iter 100) must be in scroll section"
        );
    }

    #[test]
    fn dmg_boot_rom_hold_phase_uses_32_iterations() {
        // Real hardware holds the logo for 32 iterations (× 2 VBlanks each
        // = ~64 frames ≈ 1 second) before handing off to the cartridge.
        // The hold counter value $20 (32) must appear as an immediate load
        // in the scroll section.
        let scroll_section = &DMG_BOOT_ROM[0x5A..0xFE];
        // Look for LD D,$20 pattern (16 20)
        assert!(
            scroll_section.windows(2).any(|w| w == [0x16, 0x20]),
            "hold phase must load D with $20 (32 iterations)"
        );
    }

    #[test]
    fn dmg_boot_rom_uses_ly_polling_for_vblank() {
        // Real hardware uses LDH A,[$FF44] (F0 44) to poll LY for VBlank
        // detection instead of fixed delay loops. The scroll section must
        // contain this pattern.
        let scroll_section = &DMG_BOOT_ROM[0x5A..0xFE];
        assert!(
            scroll_section.windows(2).any(|w| w == [0xF0, 0x44]),
            "scroll loop must poll LY via LDH A,[$FF44] for VBlank sync"
        );
    }

    #[test]
    fn dmg_boot_rom_does_not_embed_canonical_nintendo_logo_bytes() {
        assert!(
            !DMG_BOOT_ROM
                .windows(48)
                .any(|window| crc32(window) == CANONICAL_NINTENDO_LOGO_CRC32),
            "DMG boot ROM must not embed the canonical 48-byte Nintendo logo"
        );
    }
}