src/gb/io.c (view raw)
1/* Copyright (c) 2013-2016 Jeffrey Pfau
2 *
3 * This Source Code Form is subject to the terms of the Mozilla Public
4 * License, v. 2.0. If a copy of the MPL was not distributed with this
5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
6#include <mgba/internal/gb/io.h>
7
8#include <mgba/internal/gb/gb.h>
9#include <mgba/internal/gb/sio.h>
10#include <mgba/internal/gb/serialize.h>
11
12mLOG_DEFINE_CATEGORY(GB_IO, "GB I/O", "gb.io");
13
14const char* const GBIORegisterNames[] = {
15 [REG_JOYP] = "JOYP",
16 [REG_SB] = "SB",
17 [REG_SC] = "SC",
18 [REG_DIV] = "DIV",
19 [REG_TIMA] = "TIMA",
20 [REG_TMA] = "TMA",
21 [REG_TAC] = "TAC",
22 [REG_IF] = "IF",
23 [REG_NR10] = "NR10",
24 [REG_NR11] = "NR11",
25 [REG_NR12] = "NR12",
26 [REG_NR13] = "NR13",
27 [REG_NR14] = "NR14",
28 [REG_NR21] = "NR21",
29 [REG_NR22] = "NR22",
30 [REG_NR23] = "NR23",
31 [REG_NR24] = "NR24",
32 [REG_NR30] = "NR30",
33 [REG_NR31] = "NR31",
34 [REG_NR32] = "NR32",
35 [REG_NR33] = "NR33",
36 [REG_NR34] = "NR34",
37 [REG_NR41] = "NR41",
38 [REG_NR42] = "NR42",
39 [REG_NR43] = "NR43",
40 [REG_NR44] = "NR44",
41 [REG_NR50] = "NR50",
42 [REG_NR51] = "NR51",
43 [REG_NR52] = "NR52",
44 [REG_LCDC] = "LCDC",
45 [REG_STAT] = "STAT",
46 [REG_SCY] = "SCY",
47 [REG_SCX] = "SCX",
48 [REG_LY] = "LY",
49 [REG_LYC] = "LYC",
50 [REG_DMA] = "DMA",
51 [REG_BGP] = "BGP",
52 [REG_OBP0] = "OBP0",
53 [REG_OBP1] = "OBP1",
54 [REG_WY] = "WY",
55 [REG_WX] = "WX",
56 [REG_KEY1] = "KEY1",
57 [REG_VBK] = "VBK",
58 [REG_HDMA1] = "HDMA1",
59 [REG_HDMA2] = "HDMA2",
60 [REG_HDMA3] = "HDMA3",
61 [REG_HDMA4] = "HDMA4",
62 [REG_HDMA5] = "HDMA5",
63 [REG_RP] = "RP",
64 [REG_BCPS] = "BCPS",
65 [REG_BCPD] = "BCPD",
66 [REG_OCPS] = "OCPS",
67 [REG_OCPD] = "OCPD",
68 [REG_SVBK] = "SVBK",
69 [REG_IE] = "IE",
70};
71
72static const uint8_t _registerMask[] = {
73 [REG_SC] = 0x7E, // TODO: GBC differences
74 [REG_IF] = 0xE0,
75 [REG_TAC] = 0xF8,
76 [REG_NR10] = 0x80,
77 [REG_NR11] = 0x3F,
78 [REG_NR12] = 0x00,
79 [REG_NR13] = 0xFF,
80 [REG_NR14] = 0xBF,
81 [REG_NR21] = 0x3F,
82 [REG_NR22] = 0x00,
83 [REG_NR23] = 0xFF,
84 [REG_NR24] = 0xBF,
85 [REG_NR30] = 0x7F,
86 [REG_NR31] = 0xFF,
87 [REG_NR32] = 0x9F,
88 [REG_NR33] = 0xFF,
89 [REG_NR34] = 0xBF,
90 [REG_NR41] = 0xFF,
91 [REG_NR42] = 0x00,
92 [REG_NR43] = 0x00,
93 [REG_NR44] = 0xBF,
94 [REG_NR50] = 0x00,
95 [REG_NR51] = 0x00,
96 [REG_NR52] = 0x70,
97 [REG_STAT] = 0x80,
98 [REG_KEY1] = 0x7E,
99 [REG_VBK] = 0xFE,
100 [REG_OCPS] = 0x40,
101 [REG_BCPS] = 0x40,
102 [REG_UNK6C] = 0xFE,
103 [REG_SVBK] = 0xF8,
104 [REG_UNK75] = 0x8F,
105 [REG_IE] = 0xE0,
106};
107
108static void _writeSGBBits(struct GB* gb, int bits) {
109 if (!bits) {
110 gb->sgbBit = 0;
111 memset(gb->sgbPacket, 0, sizeof(gb->sgbPacket));
112 }
113 if (bits == gb->currentSgbBits) {
114 return;
115 }
116 gb->currentSgbBits = bits;
117 if (gb->sgbBit == 128 && bits == 2) {
118 GBVideoWriteSGBPacket(&gb->video, gb->sgbPacket);
119 ++gb->sgbBit;
120 }
121 if (gb->sgbBit >= 128) {
122 return;
123 }
124 switch (bits) {
125 case 1:
126 gb->sgbPacket[gb->sgbBit >> 3] |= 1 << (gb->sgbBit & 7);
127 // Fall through
128 case 2:
129 ++gb->sgbBit;
130 default:
131 break;
132 }
133}
134
135void GBIOInit(struct GB* gb) {
136 memset(gb->memory.io, 0, sizeof(gb->memory.io));
137}
138
139void GBIOReset(struct GB* gb) {
140 memset(gb->memory.io, 0, sizeof(gb->memory.io));
141
142 GBIOWrite(gb, REG_TIMA, 0);
143 GBIOWrite(gb, REG_TMA, 0);
144 GBIOWrite(gb, REG_TAC, 0);
145 GBIOWrite(gb, REG_IF, 1);
146 GBIOWrite(gb, REG_NR52, 0xF1);
147 GBIOWrite(gb, REG_NR14, 0xBF);
148 GBIOWrite(gb, REG_NR10, 0x80);
149 GBIOWrite(gb, REG_NR11, 0xBF);
150 GBIOWrite(gb, REG_NR12, 0xF3);
151 GBIOWrite(gb, REG_NR13, 0xF3);
152 GBIOWrite(gb, REG_NR24, 0xBF);
153 GBIOWrite(gb, REG_NR21, 0x3F);
154 GBIOWrite(gb, REG_NR22, 0x00);
155 GBIOWrite(gb, REG_NR34, 0xBF);
156 GBIOWrite(gb, REG_NR30, 0x7F);
157 GBIOWrite(gb, REG_NR31, 0xFF);
158 GBIOWrite(gb, REG_NR32, 0x9F);
159 GBIOWrite(gb, REG_NR44, 0xBF);
160 GBIOWrite(gb, REG_NR41, 0xFF);
161 GBIOWrite(gb, REG_NR42, 0x00);
162 GBIOWrite(gb, REG_NR43, 0x00);
163 GBIOWrite(gb, REG_NR50, 0x77);
164 GBIOWrite(gb, REG_NR51, 0xF3);
165 GBIOWrite(gb, REG_LCDC, 0x91);
166 GBIOWrite(gb, REG_SCY, 0x00);
167 GBIOWrite(gb, REG_SCX, 0x00);
168 GBIOWrite(gb, REG_LYC, 0x00);
169 GBIOWrite(gb, REG_BGP, 0xFC);
170 GBIOWrite(gb, REG_OBP0, 0xFF);
171 GBIOWrite(gb, REG_OBP1, 0xFF);
172 GBIOWrite(gb, REG_WY, 0x00);
173 GBIOWrite(gb, REG_WX, 0x00);
174 GBIOWrite(gb, REG_VBK, 0);
175 GBIOWrite(gb, REG_BCPS, 0);
176 GBIOWrite(gb, REG_OCPS, 0);
177 GBIOWrite(gb, REG_SVBK, 1);
178 GBIOWrite(gb, REG_HDMA1, 0xFF);
179 GBIOWrite(gb, REG_HDMA2, 0xFF);
180 GBIOWrite(gb, REG_HDMA3, 0xFF);
181 GBIOWrite(gb, REG_HDMA4, 0xFF);
182 gb->memory.io[REG_HDMA5] = 0xFF;
183 GBIOWrite(gb, REG_IE, 0x00);
184}
185
186void GBIOWrite(struct GB* gb, unsigned address, uint8_t value) {
187 switch (address) {
188 case REG_SB:
189 GBSIOWriteSB(&gb->sio, value);
190 break;
191 case REG_SC:
192 GBSIOWriteSC(&gb->sio, value);
193 break;
194 case REG_DIV:
195 GBTimerDivReset(&gb->timer);
196 return;
197 case REG_NR10:
198 if (gb->audio.enable) {
199 GBAudioWriteNR10(&gb->audio, value);
200 } else {
201 value = 0;
202 }
203 break;
204 case REG_NR11:
205 if (gb->audio.enable) {
206 GBAudioWriteNR11(&gb->audio, value);
207 } else {
208 if (gb->audio.style == GB_AUDIO_DMG) {
209 GBAudioWriteNR11(&gb->audio, value & _registerMask[REG_NR11]);
210 }
211 value = 0;
212 }
213 break;
214 case REG_NR12:
215 if (gb->audio.enable) {
216 GBAudioWriteNR12(&gb->audio, value);
217 } else {
218 value = 0;
219 }
220 break;
221 case REG_NR13:
222 if (gb->audio.enable) {
223 GBAudioWriteNR13(&gb->audio, value);
224 } else {
225 value = 0;
226 }
227 break;
228 case REG_NR14:
229 if (gb->audio.enable) {
230 GBAudioWriteNR14(&gb->audio, value);
231 } else {
232 value = 0;
233 }
234 break;
235 case REG_NR21:
236 if (gb->audio.enable) {
237 GBAudioWriteNR21(&gb->audio, value);
238 } else {
239 if (gb->audio.style == GB_AUDIO_DMG) {
240 GBAudioWriteNR21(&gb->audio, value & _registerMask[REG_NR21]);
241 }
242 value = 0;
243 }
244 break;
245 case REG_NR22:
246 if (gb->audio.enable) {
247 GBAudioWriteNR22(&gb->audio, value);
248 } else {
249 value = 0;
250 }
251 break;
252 case REG_NR23:
253 if (gb->audio.enable) {
254 GBAudioWriteNR23(&gb->audio, value);
255 } else {
256 value = 0;
257 }
258 break;
259 case REG_NR24:
260 if (gb->audio.enable) {
261 GBAudioWriteNR24(&gb->audio, value);
262 } else {
263 value = 0;
264 }
265 break;
266 case REG_NR30:
267 if (gb->audio.enable) {
268 GBAudioWriteNR30(&gb->audio, value);
269 } else {
270 value = 0;
271 }
272 break;
273 case REG_NR31:
274 if (gb->audio.enable || gb->audio.style == GB_AUDIO_DMG) {
275 GBAudioWriteNR31(&gb->audio, value);
276 } else {
277 value = 0;
278 }
279 break;
280 case REG_NR32:
281 if (gb->audio.enable) {
282 GBAudioWriteNR32(&gb->audio, value);
283 } else {
284 value = 0;
285 }
286 break;
287 case REG_NR33:
288 if (gb->audio.enable) {
289 GBAudioWriteNR33(&gb->audio, value);
290 } else {
291 value = 0;
292 }
293 break;
294 case REG_NR34:
295 if (gb->audio.enable) {
296 GBAudioWriteNR34(&gb->audio, value);
297 } else {
298 value = 0;
299 }
300 break;
301 case REG_NR41:
302 if (gb->audio.enable || gb->audio.style == GB_AUDIO_DMG) {
303 GBAudioWriteNR41(&gb->audio, value);
304 } else {
305 value = 0;
306 }
307 break;
308 case REG_NR42:
309 if (gb->audio.enable) {
310 GBAudioWriteNR42(&gb->audio, value);
311 } else {
312 value = 0;
313 }
314 break;
315 case REG_NR43:
316 if (gb->audio.enable) {
317 GBAudioWriteNR43(&gb->audio, value);
318 } else {
319 value = 0;
320 }
321 break;
322 case REG_NR44:
323 if (gb->audio.enable) {
324 GBAudioWriteNR44(&gb->audio, value);
325 } else {
326 value = 0;
327 }
328 break;
329 case REG_NR50:
330 if (gb->audio.enable) {
331 GBAudioWriteNR50(&gb->audio, value);
332 } else {
333 value = 0;
334 }
335 break;
336 case REG_NR51:
337 if (gb->audio.enable) {
338 GBAudioWriteNR51(&gb->audio, value);
339 } else {
340 value = 0;
341 }
342 break;
343 case REG_NR52:
344 GBAudioWriteNR52(&gb->audio, value);
345 value &= 0x80;
346 value |= gb->memory.io[REG_NR52] & 0x0F;
347 break;
348 case REG_WAVE_0:
349 case REG_WAVE_1:
350 case REG_WAVE_2:
351 case REG_WAVE_3:
352 case REG_WAVE_4:
353 case REG_WAVE_5:
354 case REG_WAVE_6:
355 case REG_WAVE_7:
356 case REG_WAVE_8:
357 case REG_WAVE_9:
358 case REG_WAVE_A:
359 case REG_WAVE_B:
360 case REG_WAVE_C:
361 case REG_WAVE_D:
362 case REG_WAVE_E:
363 case REG_WAVE_F:
364 if (!gb->audio.playingCh3 || gb->audio.style != GB_AUDIO_DMG) {
365 gb->audio.ch3.wavedata8[address - REG_WAVE_0] = value;
366 } else if(gb->audio.ch3.readable) {
367 gb->audio.ch3.wavedata8[gb->audio.ch3.window >> 1] = value;
368 }
369 break;
370 case REG_JOYP:
371 if (gb->model == GB_MODEL_SGB) {
372 _writeSGBBits(gb, (value >> 4) & 3);
373 }
374 break;
375 case REG_TIMA:
376 case REG_TMA:
377 // Handled transparently by the registers
378 break;
379 case REG_TAC:
380 value = GBTimerUpdateTAC(&gb->timer, value);
381 break;
382 case REG_IF:
383 gb->memory.io[REG_IF] = value | 0xE0;
384 GBUpdateIRQs(gb);
385 return;
386 case REG_LCDC:
387 // TODO: handle GBC differences
388 GBVideoProcessDots(&gb->video);
389 value = gb->video.renderer->writeVideoRegister(gb->video.renderer, address, value);
390 GBVideoWriteLCDC(&gb->video, value);
391 break;
392 case REG_LYC:
393 GBVideoWriteLYC(&gb->video, value);
394 break;
395 case REG_DMA:
396 GBMemoryDMA(gb, value << 8);
397 break;
398 case REG_SCY:
399 case REG_SCX:
400 case REG_WY:
401 case REG_WX:
402 GBVideoProcessDots(&gb->video);
403 value = gb->video.renderer->writeVideoRegister(gb->video.renderer, address, value);
404 break;
405 case REG_BGP:
406 case REG_OBP0:
407 case REG_OBP1:
408 GBVideoProcessDots(&gb->video);
409 GBVideoWritePalette(&gb->video, address, value);
410 break;
411 case REG_STAT:
412 GBVideoWriteSTAT(&gb->video, value);
413 value = gb->video.stat;
414 break;
415 case 0x50:
416 if (gb->memory.romBase < gb->memory.rom || gb->memory.romBase > &gb->memory.rom[gb->memory.romSize - 1]) {
417 free(gb->memory.romBase);
418 gb->memory.romBase = gb->memory.rom;
419 }
420 break;
421 case REG_IE:
422 gb->memory.ie = value;
423 GBUpdateIRQs(gb);
424 return;
425 default:
426 if (gb->model >= GB_MODEL_CGB) {
427 switch (address) {
428 case REG_KEY1:
429 value &= 0x1;
430 value |= gb->memory.io[address] & 0x80;
431 break;
432 case REG_VBK:
433 GBVideoSwitchBank(&gb->video, value);
434 break;
435 case REG_HDMA1:
436 case REG_HDMA2:
437 case REG_HDMA3:
438 case REG_HDMA4:
439 // Handled transparently by the registers
440 break;
441 case REG_HDMA5:
442 GBMemoryWriteHDMA5(gb, value);
443 value &= 0x7F;
444 break;
445 case REG_BCPS:
446 gb->video.bcpIndex = value & 0x3F;
447 gb->video.bcpIncrement = value & 0x80;
448 gb->memory.io[REG_BCPD] = gb->video.palette[gb->video.bcpIndex >> 1] >> (8 * (gb->video.bcpIndex & 1));
449 break;
450 case REG_BCPD:
451 GBVideoProcessDots(&gb->video);
452 GBVideoWritePalette(&gb->video, address, value);
453 return;
454 case REG_OCPS:
455 gb->video.ocpIndex = value & 0x3F;
456 gb->video.ocpIncrement = value & 0x80;
457 gb->memory.io[REG_OCPD] = gb->video.palette[8 * 4 + (gb->video.ocpIndex >> 1)] >> (8 * (gb->video.ocpIndex & 1));
458 break;
459 case REG_OCPD:
460 GBVideoProcessDots(&gb->video);
461 GBVideoWritePalette(&gb->video, address, value);
462 return;
463 case REG_SVBK:
464 GBMemorySwitchWramBank(&gb->memory, value);
465 value = gb->memory.wramCurrentBank;
466 break;
467 default:
468 goto failed;
469 }
470 goto success;
471 }
472 failed:
473 mLOG(GB_IO, STUB, "Writing to unknown register FF%02X:%02X", address, value);
474 if (address >= GB_SIZE_IO) {
475 return;
476 }
477 break;
478 }
479 success:
480 gb->memory.io[address] = value;
481}
482
483static uint8_t _readKeys(struct GB* gb) {
484 uint8_t keys = *gb->keySource;
485 switch (gb->memory.io[REG_JOYP] & 0x30) {
486 case 0x30:
487 // TODO: Increment
488 keys = gb->model == GB_MODEL_SGB ? 0xF : 0;
489 break;
490 case 0x20:
491 keys >>= 4;
492 break;
493 case 0x10:
494 break;
495 case 0x00:
496 keys |= keys >> 4;
497 break;
498 }
499 return (0xC0 | (gb->memory.io[REG_JOYP] | 0xF)) ^ (keys & 0xF);
500}
501
502uint8_t GBIORead(struct GB* gb, unsigned address) {
503 switch (address) {
504 case REG_JOYP:
505 return _readKeys(gb);
506 case REG_IE:
507 return gb->memory.ie;
508 case REG_WAVE_0:
509 case REG_WAVE_1:
510 case REG_WAVE_2:
511 case REG_WAVE_3:
512 case REG_WAVE_4:
513 case REG_WAVE_5:
514 case REG_WAVE_6:
515 case REG_WAVE_7:
516 case REG_WAVE_8:
517 case REG_WAVE_9:
518 case REG_WAVE_A:
519 case REG_WAVE_B:
520 case REG_WAVE_C:
521 case REG_WAVE_D:
522 case REG_WAVE_E:
523 case REG_WAVE_F:
524 if (gb->audio.playingCh3) {
525 if (gb->audio.ch3.readable || gb->audio.style != GB_AUDIO_DMG) {
526 return gb->audio.ch3.wavedata8[gb->audio.ch3.window >> 1];
527 } else {
528 return 0xFF;
529 }
530 } else {
531 return gb->audio.ch3.wavedata8[address - REG_WAVE_0];
532 }
533 break;
534 case REG_SB:
535 case REG_SC:
536 case REG_IF:
537 case REG_NR10:
538 case REG_NR11:
539 case REG_NR12:
540 case REG_NR14:
541 case REG_NR21:
542 case REG_NR22:
543 case REG_NR24:
544 case REG_NR30:
545 case REG_NR32:
546 case REG_NR34:
547 case REG_NR41:
548 case REG_NR42:
549 case REG_NR43:
550 case REG_NR44:
551 case REG_NR50:
552 case REG_NR51:
553 case REG_NR52:
554 case REG_DIV:
555 case REG_TIMA:
556 case REG_TMA:
557 case REG_TAC:
558 case REG_STAT:
559 case REG_LCDC:
560 case REG_SCY:
561 case REG_SCX:
562 case REG_LY:
563 case REG_LYC:
564 case REG_BGP:
565 case REG_OBP0:
566 case REG_OBP1:
567 case REG_WY:
568 case REG_WX:
569 // Handled transparently by the registers
570 break;
571 default:
572 if (gb->model >= GB_MODEL_CGB) {
573 switch (address) {
574 case REG_KEY1:
575 case REG_VBK:
576 case REG_HDMA1:
577 case REG_HDMA2:
578 case REG_HDMA3:
579 case REG_HDMA4:
580 case REG_HDMA5:
581 case REG_BCPS:
582 case REG_BCPD:
583 case REG_OCPS:
584 case REG_OCPD:
585 case REG_SVBK:
586 // Handled transparently by the registers
587 goto success;
588 default:
589 break;
590 }
591 }
592 mLOG(GB_IO, STUB, "Reading from unknown register FF%02X", address);
593 return 0xFF;
594 }
595 success:
596 return gb->memory.io[address] | _registerMask[address];
597}
598
599void GBTestKeypadIRQ(struct GB* gb) {
600 if (_readKeys(gb)) {
601 gb->memory.io[REG_IF] |= (1 << GB_IRQ_KEYPAD);
602 GBUpdateIRQs(gb);
603 }
604}
605
606struct GBSerializedState;
607void GBIOSerialize(const struct GB* gb, struct GBSerializedState* state) {
608 memcpy(state->io, gb->memory.io, GB_SIZE_IO);
609 state->ie = gb->memory.ie;
610}
611
612void GBIODeserialize(struct GB* gb, const struct GBSerializedState* state) {
613 memcpy(gb->memory.io, state->io, GB_SIZE_IO);
614 gb->memory.ie = state->ie;
615
616 if (GBAudioEnableGetEnable(*gb->audio.nr52)) {
617 GBIOWrite(gb, REG_NR10, gb->memory.io[REG_NR10]);
618 GBIOWrite(gb, REG_NR11, gb->memory.io[REG_NR11]);
619 GBIOWrite(gb, REG_NR12, gb->memory.io[REG_NR12]);
620 GBIOWrite(gb, REG_NR13, gb->memory.io[REG_NR13]);
621 gb->audio.ch1.control.frequency &= 0xFF;
622 gb->audio.ch1.control.frequency |= GBAudioRegisterControlGetFrequency(gb->memory.io[REG_NR14] << 8);
623 gb->audio.ch1.control.stop = GBAudioRegisterControlGetStop(gb->memory.io[REG_NR14] << 8);
624 GBIOWrite(gb, REG_NR21, gb->memory.io[REG_NR21]);
625 GBIOWrite(gb, REG_NR22, gb->memory.io[REG_NR22]);
626 GBIOWrite(gb, REG_NR22, gb->memory.io[REG_NR23]);
627 gb->audio.ch2.control.frequency &= 0xFF;
628 gb->audio.ch2.control.frequency |= GBAudioRegisterControlGetFrequency(gb->memory.io[REG_NR24] << 8);
629 gb->audio.ch2.control.stop = GBAudioRegisterControlGetStop(gb->memory.io[REG_NR24] << 8);
630 GBIOWrite(gb, REG_NR30, gb->memory.io[REG_NR30]);
631 GBIOWrite(gb, REG_NR31, gb->memory.io[REG_NR31]);
632 GBIOWrite(gb, REG_NR32, gb->memory.io[REG_NR32]);
633 GBIOWrite(gb, REG_NR32, gb->memory.io[REG_NR33]);
634 gb->audio.ch3.rate &= 0xFF;
635 gb->audio.ch3.rate |= GBAudioRegisterControlGetRate(gb->memory.io[REG_NR34] << 8);
636 gb->audio.ch3.stop = GBAudioRegisterControlGetStop(gb->memory.io[REG_NR34] << 8);
637 GBIOWrite(gb, REG_NR41, gb->memory.io[REG_NR41]);
638 GBIOWrite(gb, REG_NR42, gb->memory.io[REG_NR42]);
639 GBIOWrite(gb, REG_NR43, gb->memory.io[REG_NR43]);
640 gb->audio.ch4.stop = GBAudioRegisterNoiseControlGetStop(gb->memory.io[REG_NR44]);
641 GBIOWrite(gb, REG_NR50, gb->memory.io[REG_NR50]);
642 GBIOWrite(gb, REG_NR51, gb->memory.io[REG_NR51]);
643 }
644
645 gb->video.renderer->writeVideoRegister(gb->video.renderer, REG_LCDC, state->io[REG_LCDC]);
646 gb->video.renderer->writeVideoRegister(gb->video.renderer, REG_SCY, state->io[REG_SCY]);
647 gb->video.renderer->writeVideoRegister(gb->video.renderer, REG_SCX, state->io[REG_SCX]);
648 gb->video.renderer->writeVideoRegister(gb->video.renderer, REG_WY, state->io[REG_WY]);
649 gb->video.renderer->writeVideoRegister(gb->video.renderer, REG_WX, state->io[REG_WX]);
650}