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mGBA Game Boy Advance Emulator

src/gb/gb.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/gb.h>
  7
  8#include <mgba/internal/gb/io.h>
  9#include <mgba/internal/gb/mbc.h>
 10#include <mgba/internal/sm83/sm83.h>
 11
 12#include <mgba/core/core.h>
 13#include <mgba/core/cheats.h>
 14#include <mgba-util/crc32.h>
 15#include <mgba-util/memory.h>
 16#include <mgba-util/math.h>
 17#include <mgba-util/patch.h>
 18#include <mgba-util/vfs.h>
 19
 20#define CLEANUP_THRESHOLD 15
 21
 22const uint32_t CGB_SM83_FREQUENCY = 0x800000;
 23const uint32_t SGB_SM83_FREQUENCY = 0x418B1E;
 24
 25const uint32_t GB_COMPONENT_MAGIC = 0x400000;
 26
 27static const uint8_t _knownHeader[4] = { 0xCE, 0xED, 0x66, 0x66};
 28
 29#define DMG_BIOS_CHECKSUM 0xC2F5CC97
 30#define DMG_2_BIOS_CHECKSUM 0x59C8598E
 31#define MGB_BIOS_CHECKSUM 0xE6920754
 32#define SGB_BIOS_CHECKSUM 0xEC8A83B9
 33#define SGB2_BIOS_CHECKSUM 0X53D0DD63
 34#define CGB_BIOS_CHECKSUM 0x41884E46
 35
 36mLOG_DEFINE_CATEGORY(GB, "GB", "gb");
 37
 38static void GBInit(void* cpu, struct mCPUComponent* component);
 39static void GBDeinit(struct mCPUComponent* component);
 40static void GBInterruptHandlerInit(struct SM83InterruptHandler* irqh);
 41static void GBProcessEvents(struct SM83Core* cpu);
 42static void GBSetInterrupts(struct SM83Core* cpu, bool enable);
 43static uint16_t GBIRQVector(struct SM83Core* cpu);
 44static void GBIllegal(struct SM83Core* cpu);
 45static void GBStop(struct SM83Core* cpu);
 46
 47static void _enableInterrupts(struct mTiming* timing, void* user, uint32_t cyclesLate);
 48
 49void GBCreate(struct GB* gb) {
 50	gb->d.id = GB_COMPONENT_MAGIC;
 51	gb->d.init = GBInit;
 52	gb->d.deinit = GBDeinit;
 53}
 54
 55static void GBInit(void* cpu, struct mCPUComponent* component) {
 56	struct GB* gb = (struct GB*) component;
 57	gb->cpu = cpu;
 58	gb->sync = NULL;
 59
 60	GBInterruptHandlerInit(&gb->cpu->irqh);
 61	GBMemoryInit(gb);
 62
 63	gb->video.p = gb;
 64	GBVideoInit(&gb->video);
 65
 66	gb->audio.p = gb;
 67	GBAudioInit(&gb->audio, 2048, &gb->memory.io[GB_REG_NR52], GB_AUDIO_DMG); // TODO: Remove magic constant
 68
 69	gb->sio.p = gb;
 70	GBSIOInit(&gb->sio);
 71
 72	gb->timer.p = gb;
 73
 74	gb->model = GB_MODEL_AUTODETECT;
 75
 76	gb->biosVf = NULL;
 77	gb->romVf = NULL;
 78	gb->sramVf = NULL;
 79	gb->sramRealVf = NULL;
 80
 81	gb->isPristine = false;
 82	gb->pristineRomSize = 0;
 83	gb->yankedRomSize = 0;
 84
 85	mCoreCallbacksListInit(&gb->coreCallbacks, 0);
 86	gb->stream = NULL;
 87
 88	mTimingInit(&gb->timing, &gb->cpu->cycles, &gb->cpu->nextEvent);
 89	gb->audio.timing = &gb->timing;
 90
 91	gb->eiPending.name = "GB EI";
 92	gb->eiPending.callback = _enableInterrupts;
 93	gb->eiPending.context = gb;
 94	gb->eiPending.priority = 0;
 95}
 96
 97static void GBDeinit(struct mCPUComponent* component) {
 98	struct GB* gb = (struct GB*) component;
 99	mTimingDeinit(&gb->timing);
100}
101
102bool GBLoadROM(struct GB* gb, struct VFile* vf) {
103	if (!vf) {
104		return false;
105	}
106	GBUnloadROM(gb);
107	gb->romVf = vf;
108	gb->pristineRomSize = vf->size(vf);
109	vf->seek(vf, 0, SEEK_SET);
110	gb->isPristine = true;
111	gb->memory.rom = vf->map(vf, gb->pristineRomSize, MAP_READ);
112	if (!gb->memory.rom) {
113		return false;
114	}
115	gb->yankedRomSize = 0;
116	gb->memory.romSize = gb->pristineRomSize;
117	gb->romCrc32 = doCrc32(gb->memory.rom, gb->memory.romSize);
118	memset(&gb->memory.mbcState, 0, sizeof(gb->memory.mbcState));
119	GBMBCReset(gb);
120
121	if (gb->cpu) {
122		struct SM83Core* cpu = gb->cpu;
123		cpu->memory.setActiveRegion(cpu, cpu->pc);
124	}
125
126	// TODO: error check
127	return true;
128}
129
130void GBYankROM(struct GB* gb) {
131	gb->yankedRomSize = gb->memory.romSize;
132	gb->yankedMbc = gb->memory.mbcType;
133	gb->memory.romSize = 0;
134	gb->memory.mbcType = GB_MBC_NONE;
135	GBMBCReset(gb);
136
137	if (gb->cpu) {
138		struct SM83Core* cpu = gb->cpu;
139		cpu->memory.setActiveRegion(cpu, cpu->pc);
140	}
141}
142
143static void GBSramDeinit(struct GB* gb) {
144	if (gb->sramVf) {
145		gb->sramVf->unmap(gb->sramVf, gb->memory.sram, gb->sramSize);
146		if (gb->memory.mbcType == GB_MBC3_RTC && gb->sramVf == gb->sramRealVf) {
147			GBMBCRTCWrite(gb);
148		}
149		gb->sramVf = NULL;
150	} else if (gb->memory.sram) {
151		mappedMemoryFree(gb->memory.sram, gb->sramSize);
152	}
153	gb->memory.sram = 0;
154}
155
156bool GBLoadSave(struct GB* gb, struct VFile* vf) {
157	GBSramDeinit(gb);
158	gb->sramVf = vf;
159	gb->sramRealVf = vf;
160	if (gb->sramSize) {
161		GBResizeSram(gb, gb->sramSize);
162		GBMBCSwitchSramBank(gb, gb->memory.sramCurrentBank);
163
164		if (gb->memory.mbcType == GB_MBC3_RTC) {
165			GBMBCRTCRead(gb);
166		}
167	}
168	return vf;
169}
170
171void GBResizeSram(struct GB* gb, size_t size) {
172	if (gb->memory.sram && size <= gb->sramSize) {
173		return;
174	}
175	struct VFile* vf = gb->sramVf;
176	if (vf) {
177		if (vf == gb->sramRealVf) {
178			ssize_t vfSize = vf->size(vf);
179			if (vfSize >= 0 && (size_t) vfSize < size) {
180				uint8_t extdataBuffer[0x100];
181				if (vfSize & 0xFF) {
182					vf->seek(vf, -(vfSize & 0xFF), SEEK_END);
183					vf->read(vf, extdataBuffer, vfSize & 0xFF);
184				}
185				if (gb->memory.sram) {
186					vf->unmap(vf, gb->memory.sram, gb->sramSize);
187				}
188				vf->truncate(vf, size + (vfSize & 0xFF));
189				if (vfSize & 0xFF) {
190					vf->seek(vf, size, SEEK_SET);
191					vf->write(vf, extdataBuffer, vfSize & 0xFF);
192				}
193				gb->memory.sram = vf->map(vf, size, MAP_WRITE);
194				memset(&gb->memory.sram[vfSize], 0xFF, size - vfSize);
195			} else if (size > gb->sramSize || !gb->memory.sram) {
196				if (gb->memory.sram) {
197					vf->unmap(vf, gb->memory.sram, gb->sramSize);
198				}
199				gb->memory.sram = vf->map(vf, size, MAP_WRITE);
200			}
201		} else {
202			if (gb->memory.sram) {
203				vf->unmap(vf, gb->memory.sram, gb->sramSize);
204			}
205			gb->memory.sram = vf->map(vf, size, MAP_READ);
206		}
207		if (gb->memory.sram == (void*) -1) {
208			gb->memory.sram = NULL;
209		}
210	} else if (size) {
211		uint8_t* newSram = anonymousMemoryMap(size);
212		if (gb->memory.sram) {
213			if (size > gb->sramSize) {
214				memcpy(newSram, gb->memory.sram, gb->sramSize);
215				memset(&newSram[gb->sramSize], 0xFF, size - gb->sramSize);
216			} else {
217				memcpy(newSram, gb->memory.sram, size);
218			}
219			mappedMemoryFree(gb->memory.sram, gb->sramSize);
220		} else {
221			memset(newSram, 0xFF, size);
222		}
223		gb->memory.sram = newSram;
224	}
225	if (gb->sramSize < size) {
226		gb->sramSize = size;
227	}
228}
229
230void GBSramClean(struct GB* gb, uint32_t frameCount) {
231	// TODO: Share with GBASavedataClean
232	if (!gb->sramVf) {
233		return;
234	}
235	if (gb->sramDirty & GB_SRAM_DIRT_NEW) {
236		gb->sramDirtAge = frameCount;
237		gb->sramDirty &= ~GB_SRAM_DIRT_NEW;
238		if (!(gb->sramDirty & GB_SRAM_DIRT_SEEN)) {
239			gb->sramDirty |= GB_SRAM_DIRT_SEEN;
240		}
241	} else if ((gb->sramDirty & GB_SRAM_DIRT_SEEN) && frameCount - gb->sramDirtAge > CLEANUP_THRESHOLD) {
242		if (gb->sramMaskWriteback) {
243			GBSavedataUnmask(gb);
244		}
245		if (gb->memory.mbcType == GB_MBC3_RTC) {
246			GBMBCRTCWrite(gb);
247		}
248		gb->sramDirty = 0;
249		if (gb->memory.sram && gb->sramVf->sync(gb->sramVf, gb->memory.sram, gb->sramSize)) {
250			mLOG(GB_MEM, INFO, "Savedata synced");
251		} else {
252			mLOG(GB_MEM, INFO, "Savedata failed to sync!");
253		}
254
255		size_t c;
256		for (c = 0; c < mCoreCallbacksListSize(&gb->coreCallbacks); ++c) {
257			struct mCoreCallbacks* callbacks = mCoreCallbacksListGetPointer(&gb->coreCallbacks, c);
258			if (callbacks->savedataUpdated) {
259				callbacks->savedataUpdated(callbacks->context);
260			}
261		}
262	}
263}
264
265void GBSavedataMask(struct GB* gb, struct VFile* vf, bool writeback) {
266	struct VFile* oldVf = gb->sramVf;
267	GBSramDeinit(gb);
268	if (oldVf && oldVf != gb->sramRealVf) {
269		oldVf->close(oldVf);
270	}
271	gb->sramVf = vf;
272	gb->sramMaskWriteback = writeback;
273	gb->memory.sram = vf->map(vf, gb->sramSize, MAP_READ);
274	GBMBCSwitchSramBank(gb, gb->memory.sramCurrentBank);
275}
276
277void GBSavedataUnmask(struct GB* gb) {
278	if (!gb->sramRealVf || gb->sramVf == gb->sramRealVf) {
279		return;
280	}
281	struct VFile* vf = gb->sramVf;
282	GBSramDeinit(gb);
283	gb->sramVf = gb->sramRealVf;
284	gb->memory.sram = gb->sramVf->map(gb->sramVf, gb->sramSize, MAP_WRITE);
285	if (gb->sramMaskWriteback) {
286		vf->seek(vf, 0, SEEK_SET);
287		vf->read(vf, gb->memory.sram, gb->sramSize);
288		gb->sramMaskWriteback = false;
289	}
290	GBMBCSwitchSramBank(gb, gb->memory.sramCurrentBank);
291	vf->close(vf);
292}
293
294void GBUnloadROM(struct GB* gb) {
295	// TODO: Share with GBAUnloadROM
296	if (gb->memory.rom && !gb->isPristine) {
297		if (gb->yankedRomSize) {
298			gb->yankedRomSize = 0;
299		}
300		mappedMemoryFree(gb->memory.rom, GB_SIZE_CART_MAX);
301	}
302
303	if (gb->romVf) {
304#ifndef FIXED_ROM_BUFFER
305		gb->romVf->unmap(gb->romVf, gb->memory.rom, gb->pristineRomSize);
306#endif
307		gb->romVf->close(gb->romVf);
308		gb->romVf = NULL;
309	}
310	gb->memory.rom = NULL;
311	gb->memory.mbcType = GB_MBC_AUTODETECT;
312	gb->isPristine = false;
313
314	gb->sramMaskWriteback = false;
315	GBSavedataUnmask(gb);
316	GBSramDeinit(gb);
317	if (gb->sramRealVf) {
318		gb->sramRealVf->close(gb->sramRealVf);
319	}
320	gb->sramRealVf = NULL;
321	gb->sramVf = NULL;
322	if (gb->memory.cam && gb->memory.cam->stopRequestImage) {
323		gb->memory.cam->stopRequestImage(gb->memory.cam);
324	}
325}
326
327void GBSynthesizeROM(struct VFile* vf) {
328	if (!vf) {
329		return;
330	}
331	const struct GBCartridge cart = {
332		.logo = { _knownHeader[0], _knownHeader[1], _knownHeader[2], _knownHeader[3]}
333	};
334
335	vf->seek(vf, 0x100, SEEK_SET);
336	vf->write(vf, &cart, sizeof(cart));
337}
338
339void GBLoadBIOS(struct GB* gb, struct VFile* vf) {
340	gb->biosVf = vf;
341}
342
343void GBApplyPatch(struct GB* gb, struct Patch* patch) {
344	size_t patchedSize = patch->outputSize(patch, gb->memory.romSize);
345	if (!patchedSize) {
346		return;
347	}
348	if (patchedSize > GB_SIZE_CART_MAX) {
349		patchedSize = GB_SIZE_CART_MAX;
350	}
351	void* newRom = anonymousMemoryMap(GB_SIZE_CART_MAX);
352	if (!patch->applyPatch(patch, gb->memory.rom, gb->pristineRomSize, newRom, patchedSize)) {
353		mappedMemoryFree(newRom, GB_SIZE_CART_MAX);
354		return;
355	}
356	if (gb->romVf) {
357#ifndef FIXED_ROM_BUFFER
358		gb->romVf->unmap(gb->romVf, gb->memory.rom, gb->pristineRomSize);
359#endif
360		gb->romVf->close(gb->romVf);
361		gb->romVf = NULL;
362	}
363	gb->isPristine = false;
364	if (gb->memory.romBase == gb->memory.rom) {
365		gb->memory.romBase = newRom;
366	}
367	gb->memory.rom = newRom;
368	gb->memory.romSize = patchedSize;
369	gb->romCrc32 = doCrc32(gb->memory.rom, gb->memory.romSize);
370	gb->cpu->memory.setActiveRegion(gb->cpu, gb->cpu->pc);
371}
372
373void GBDestroy(struct GB* gb) {
374	GBUnmapBIOS(gb);
375	GBUnloadROM(gb);
376
377	if (gb->biosVf) {
378		gb->biosVf->close(gb->biosVf);
379		gb->biosVf = 0;
380	}
381
382	GBMemoryDeinit(gb);
383	GBAudioDeinit(&gb->audio);
384	GBVideoDeinit(&gb->video);
385	GBSIODeinit(&gb->sio);
386	mCoreCallbacksListDeinit(&gb->coreCallbacks);
387}
388
389void GBInterruptHandlerInit(struct SM83InterruptHandler* irqh) {
390	irqh->reset = GBReset;
391	irqh->processEvents = GBProcessEvents;
392	irqh->setInterrupts = GBSetInterrupts;
393	irqh->irqVector = GBIRQVector;
394	irqh->hitIllegal = GBIllegal;
395	irqh->stop = GBStop;
396	irqh->halt = GBHalt;
397}
398
399static uint32_t _GBBiosCRC32(struct VFile* vf) {
400	ssize_t size = vf->size(vf);
401	if (size <= 0 || size > GB_SIZE_CART_BANK0) {
402		return 0;
403	}
404	void* bios = vf->map(vf, size, MAP_READ);
405	uint32_t biosCrc = doCrc32(bios, size);
406	vf->unmap(vf, bios, size);
407	return biosCrc;
408}
409
410bool GBIsBIOS(struct VFile* vf) {
411	switch (_GBBiosCRC32(vf)) {
412	case DMG_BIOS_CHECKSUM:
413	case DMG_2_BIOS_CHECKSUM:
414	case MGB_BIOS_CHECKSUM:
415	case SGB_BIOS_CHECKSUM:
416	case SGB2_BIOS_CHECKSUM:
417	case CGB_BIOS_CHECKSUM:
418		return true;
419	default:
420		return false;
421	}
422}
423
424void GBReset(struct SM83Core* cpu) {
425	struct GB* gb = (struct GB*) cpu->master;
426	gb->memory.romBase = gb->memory.rom;
427	GBDetectModel(gb);
428
429	cpu->b = 0;
430	cpu->d = 0;
431
432	gb->timer.internalDiv = 0;
433
434	gb->cpuBlocked = false;
435	gb->earlyExit = false;
436	gb->doubleSpeed = 0;
437
438	if (gb->yankedRomSize) {
439		gb->memory.romSize = gb->yankedRomSize;
440		gb->memory.mbcType = gb->yankedMbc;
441		gb->yankedRomSize = 0;
442	}
443
444	gb->sgbBit = -1;
445	gb->sgbControllers = 0;
446	gb->sgbCurrentController = 0;
447	gb->currentSgbBits = 0;
448	gb->sgbIncrement = false;
449	memset(gb->sgbPacket, 0, sizeof(gb->sgbPacket));
450
451	mTimingClear(&gb->timing);
452
453	GBMemoryReset(gb);
454
455	if (gb->biosVf) {
456		if (!GBIsBIOS(gb->biosVf)) {
457			gb->biosVf->close(gb->biosVf);
458			gb->biosVf = NULL;
459		} else {
460			GBMapBIOS(gb);
461			cpu->a = 0;
462			cpu->f.packed = 0;
463			cpu->c = 0;
464			cpu->e = 0;
465			cpu->h = 0;
466			cpu->l = 0;
467			cpu->sp = 0;
468			cpu->pc = 0;
469		}
470	}
471
472	GBVideoReset(&gb->video);
473	GBTimerReset(&gb->timer);
474	GBIOReset(gb);
475	if (!gb->biosVf && gb->memory.rom) {
476		GBSkipBIOS(gb);
477	} else {
478		mTimingSchedule(&gb->timing, &gb->timer.event, 0);
479	}
480
481	GBAudioReset(&gb->audio);
482	GBSIOReset(&gb->sio);
483
484	cpu->memory.setActiveRegion(cpu, cpu->pc);
485
486	gb->sramMaskWriteback = false;
487	GBSavedataUnmask(gb);
488}
489
490void GBSkipBIOS(struct GB* gb) {
491	struct SM83Core* cpu = gb->cpu;
492	const struct GBCartridge* cart = (const struct GBCartridge*) &gb->memory.rom[0x100];
493	int nextDiv = 0;
494
495	switch (gb->model) {
496	case GB_MODEL_AUTODETECT: // Silence warnings
497		gb->model = GB_MODEL_DMG;
498		// Fall through
499	case GB_MODEL_DMG:
500		cpu->a = 1;
501		cpu->f.packed = 0xB0;
502		cpu->c = 0x13;
503		cpu->e = 0xD8;
504		cpu->h = 1;
505		cpu->l = 0x4D;
506		gb->timer.internalDiv = 0xABC;
507		nextDiv = 4;
508		break;
509	case GB_MODEL_SGB:
510		cpu->a = 1;
511		cpu->f.packed = 0x00;
512		cpu->c = 0x14;
513		cpu->e = 0x00;
514		cpu->h = 0xC0;
515		cpu->l = 0x60;
516		gb->timer.internalDiv = 0xD85;
517		nextDiv = 8;
518		break;
519	case GB_MODEL_MGB:
520		cpu->a = 0xFF;
521		cpu->f.packed = 0xB0;
522		cpu->c = 0x13;
523		cpu->e = 0xD8;
524		cpu->h = 1;
525		cpu->l = 0x4D;
526		gb->timer.internalDiv = 0xABC;
527		nextDiv = 4;
528		break;
529	case GB_MODEL_SGB2:
530		cpu->a = 0xFF;
531		cpu->f.packed = 0x00;
532		cpu->c = 0x14;
533		cpu->e = 0x00;
534		cpu->h = 0xC0;
535		cpu->l = 0x60;
536		gb->timer.internalDiv = 0xD84;
537		nextDiv = 8;
538		break;
539	case GB_MODEL_AGB:
540		cpu->b = 1;
541		// Fall through
542	case GB_MODEL_CGB:
543		cpu->a = 0x11;
544		if (gb->model == GB_MODEL_AGB) {
545			cpu->f.packed = 0x00;
546		} else {
547			cpu->f.packed = 0x80;
548		}
549		cpu->c = 0;
550		cpu->h = 0;
551		if (cart->cgb & 0x80) {
552			cpu->d = 0xFF;
553			cpu->e = 0x56;
554			cpu->l = 0x0D;
555			gb->timer.internalDiv = 0x2F0;
556		} else {
557			cpu->e = 0x08;
558			cpu->l = 0x7C;
559			gb->timer.internalDiv = 0x260;
560			gb->model = GB_MODEL_DMG;
561			gb->memory.io[GB_REG_KEY1] = 0xFF;
562			gb->memory.io[GB_REG_BCPS] = 0x88; // Faked writing 4 BG palette entries
563			gb->memory.io[GB_REG_OCPS] = 0x90; // Faked writing 8 OBJ palette entries
564			gb->memory.io[GB_REG_SVBK] = 0xFF;
565			GBVideoDisableCGB(&gb->video);
566		}
567		nextDiv = 0xC;
568		break;
569	}
570
571	cpu->sp = 0xFFFE;
572	cpu->pc = 0x100;
573
574	gb->timer.nextDiv = GB_DMG_DIV_PERIOD * (16 - nextDiv);
575
576	mTimingDeschedule(&gb->timing, &gb->timer.event);
577	mTimingSchedule(&gb->timing, &gb->timer.event, gb->timer.nextDiv);
578
579	GBIOWrite(gb, GB_REG_LCDC, 0x91);
580	gb->memory.io[GB_REG_BANK] = 0x1;
581	GBVideoSkipBIOS(&gb->video);
582
583	if (gb->biosVf) {
584		GBUnmapBIOS(gb);
585	}
586}
587
588void GBMapBIOS(struct GB* gb) {
589	gb->biosVf->seek(gb->biosVf, 0, SEEK_SET);
590	gb->memory.romBase = malloc(GB_SIZE_CART_BANK0);
591	ssize_t size = gb->biosVf->read(gb->biosVf, gb->memory.romBase, GB_SIZE_CART_BANK0);
592	if (gb->memory.rom) {
593		memcpy(&gb->memory.romBase[size], &gb->memory.rom[size], GB_SIZE_CART_BANK0 - size);
594		if (size > 0x100) {
595			memcpy(&gb->memory.romBase[0x100], &gb->memory.rom[0x100], sizeof(struct GBCartridge));
596		}
597	}
598}
599
600void GBUnmapBIOS(struct GB* gb) {
601	if (gb->memory.io[GB_REG_BANK] == 0xFF && gb->memory.romBase != gb->memory.rom) {
602		free(gb->memory.romBase);
603		if (gb->memory.mbcType == GB_MMM01) {
604			GBMBCSwitchBank0(gb, gb->memory.romSize / GB_SIZE_CART_BANK0 - 2);
605		} else {
606			GBMBCSwitchBank0(gb, 0);
607		}
608	}
609	// XXX: Force AGB registers for AGB-mode
610	if (gb->model == GB_MODEL_AGB && gb->cpu->pc == 0x100) {
611		gb->cpu->b = 1;
612	}
613}
614
615void GBDetectModel(struct GB* gb) {
616	if (gb->model != GB_MODEL_AUTODETECT) {
617		return;
618	}
619	if (gb->biosVf) {
620		switch (_GBBiosCRC32(gb->biosVf)) {
621		case DMG_BIOS_CHECKSUM:
622		case DMG_2_BIOS_CHECKSUM:
623			gb->model = GB_MODEL_DMG;
624			break;
625		case MGB_BIOS_CHECKSUM:
626			gb->model = GB_MODEL_MGB;
627			break;
628		case SGB_BIOS_CHECKSUM:
629			gb->model = GB_MODEL_SGB;
630			break;
631		case SGB2_BIOS_CHECKSUM:
632			gb->model = GB_MODEL_SGB2;
633			break;
634		case CGB_BIOS_CHECKSUM:
635			gb->model = GB_MODEL_CGB;
636			break;
637		default:
638			gb->biosVf->close(gb->biosVf);
639			gb->biosVf = NULL;
640		}
641	}
642	if (gb->model == GB_MODEL_AUTODETECT && gb->memory.rom) {
643		const struct GBCartridge* cart = (const struct GBCartridge*) &gb->memory.rom[0x100];
644		if (cart->cgb & 0x80) {
645			gb->model = GB_MODEL_CGB;
646		} else if (cart->sgb == 0x03 && cart->oldLicensee == 0x33) {
647			gb->model = GB_MODEL_SGB;
648		} else {
649			gb->model = GB_MODEL_DMG;
650		}
651	}
652
653	switch (gb->model) {
654	case GB_MODEL_DMG:
655	case GB_MODEL_SGB:
656	case GB_MODEL_AUTODETECT: //Silence warnings
657		gb->audio.style = GB_AUDIO_DMG;
658		break;
659	case GB_MODEL_MGB:
660	case GB_MODEL_SGB2:
661		gb->audio.style = GB_AUDIO_MGB;
662		break;
663	case GB_MODEL_AGB:
664	case GB_MODEL_CGB:
665		gb->audio.style = GB_AUDIO_CGB;
666		break;
667	}
668}
669
670int GBValidModels(const uint8_t* bank0) {
671	const struct GBCartridge* cart = (const struct GBCartridge*) &bank0[0x100];
672	int models;
673	if (cart->cgb == 0x80) {
674		models = GB_MODEL_CGB | GB_MODEL_MGB;
675	} else if (cart->cgb == 0xC0) {
676		models = GB_MODEL_CGB;
677	} else {
678		models = GB_MODEL_MGB;		
679	}
680	if (cart->sgb == 0x03 && cart->oldLicensee == 0x33) {
681		models |= GB_MODEL_SGB;
682	}
683	return models;
684}
685
686void GBUpdateIRQs(struct GB* gb) {
687	int irqs = gb->memory.ie & gb->memory.io[GB_REG_IF] & 0x1F;
688	if (!irqs) {
689		gb->cpu->irqPending = false;
690		return;
691	}
692	gb->cpu->halted = false;
693
694	if (!gb->memory.ime) {
695		gb->cpu->irqPending = false;
696		return;
697	}
698	if (gb->cpu->irqPending) {
699		return;
700	}
701	SM83RaiseIRQ(gb->cpu);
702}
703
704void GBProcessEvents(struct SM83Core* cpu) {
705	struct GB* gb = (struct GB*) cpu->master;
706	do {
707		int32_t cycles = cpu->cycles;
708		int32_t nextEvent;
709
710		cpu->cycles = 0;
711		cpu->nextEvent = INT_MAX;
712
713		nextEvent = cycles;
714		do {
715#ifdef USE_DEBUGGERS
716			gb->timing.globalCycles += nextEvent;
717#endif
718			nextEvent = mTimingTick(&gb->timing, nextEvent);
719		} while (gb->cpuBlocked);
720		// This loop cannot early exit until the SM83 run loop properly handles mid-M-cycle-exits
721		cpu->nextEvent = nextEvent;
722
723		if (cpu->halted) {
724			cpu->cycles = cpu->nextEvent;
725			if (!gb->memory.ie || !gb->memory.ime) {
726				break;
727			}
728		}
729		if (gb->earlyExit) {
730			break;
731		}
732	} while (cpu->cycles >= cpu->nextEvent);
733	gb->earlyExit = false;
734	if (gb->cpuBlocked) {
735		cpu->cycles = cpu->nextEvent;
736	}
737}
738
739void GBSetInterrupts(struct SM83Core* cpu, bool enable) {
740	struct GB* gb = (struct GB*) cpu->master;
741	mTimingDeschedule(&gb->timing, &gb->eiPending);
742	if (!enable) {
743		gb->memory.ime = false;
744		GBUpdateIRQs(gb);
745	} else {
746		mTimingSchedule(&gb->timing, &gb->eiPending, 4 * cpu->tMultiplier);
747	}
748}
749
750uint16_t GBIRQVector(struct SM83Core* cpu) {
751	struct GB* gb = (struct GB*) cpu->master;
752	int irqs = gb->memory.ie & gb->memory.io[GB_REG_IF];
753
754	if (irqs & (1 << GB_IRQ_VBLANK)) {
755		gb->memory.io[GB_REG_IF] &= ~(1 << GB_IRQ_VBLANK);
756		return GB_VECTOR_VBLANK;
757	}
758	if (irqs & (1 << GB_IRQ_LCDSTAT)) {
759		gb->memory.io[GB_REG_IF] &= ~(1 << GB_IRQ_LCDSTAT);
760		return GB_VECTOR_LCDSTAT;
761	}
762	if (irqs & (1 << GB_IRQ_TIMER)) {
763		gb->memory.io[GB_REG_IF] &= ~(1 << GB_IRQ_TIMER);
764		return GB_VECTOR_TIMER;
765	}
766	if (irqs & (1 << GB_IRQ_SIO)) {
767		gb->memory.io[GB_REG_IF] &= ~(1 << GB_IRQ_SIO);
768		return GB_VECTOR_SIO;
769	}
770	if (irqs & (1 << GB_IRQ_KEYPAD)) {
771		gb->memory.io[GB_REG_IF] &= ~(1 << GB_IRQ_KEYPAD);
772		return GB_VECTOR_KEYPAD;
773	}
774	return 0;
775}
776
777static void _enableInterrupts(struct mTiming* timing, void* user, uint32_t cyclesLate) {
778	UNUSED(timing);
779	UNUSED(cyclesLate);
780	struct GB* gb = user;
781	gb->memory.ime = true;
782	GBUpdateIRQs(gb);
783}
784
785void GBHalt(struct SM83Core* cpu) {
786	struct GB* gb = (struct GB*) cpu->master;
787	if (!(gb->memory.ie & gb->memory.io[GB_REG_IF] & 0x1F)) {
788		cpu->cycles = cpu->nextEvent;
789		cpu->halted = true;
790	} else if (!gb->memory.ime) {
791		mLOG(GB, GAME_ERROR, "HALT bug");
792		cpu->executionState = SM83_CORE_HALT_BUG;
793	}
794}
795
796void GBStop(struct SM83Core* cpu) {
797	struct GB* gb = (struct GB*) cpu->master;
798	if (gb->model >= GB_MODEL_CGB && gb->memory.io[GB_REG_KEY1] & 1) {
799		gb->doubleSpeed ^= 1;
800		gb->cpu->tMultiplier = 2 - gb->doubleSpeed;
801		gb->memory.io[GB_REG_KEY1] = 0;
802		gb->memory.io[GB_REG_KEY1] |= gb->doubleSpeed << 7;
803	} else {
804		int sleep = ~(gb->memory.io[GB_REG_JOYP] & 0x30);
805		size_t c;
806		for (c = 0; c < mCoreCallbacksListSize(&gb->coreCallbacks); ++c) {
807			struct mCoreCallbacks* callbacks = mCoreCallbacksListGetPointer(&gb->coreCallbacks, c);
808			if (sleep && callbacks->sleep) {
809				callbacks->sleep(callbacks->context);
810			} else if (callbacks->shutdown) {
811				callbacks->shutdown(callbacks->context);
812			}
813		}
814	}
815}
816
817void GBIllegal(struct SM83Core* cpu) {
818	struct GB* gb = (struct GB*) cpu->master;
819	mLOG(GB, GAME_ERROR, "Hit illegal opcode at address %04X:%02X", cpu->pc, cpu->bus);
820#ifdef USE_DEBUGGERS
821	if (cpu->components && cpu->components[CPU_COMPONENT_DEBUGGER]) {
822		struct mDebuggerEntryInfo info = {
823			.address = cpu->pc,
824			.type.bp.opcode = cpu->bus
825		};
826		mDebuggerEnter((struct mDebugger*) cpu->components[CPU_COMPONENT_DEBUGGER], DEBUGGER_ENTER_ILLEGAL_OP, &info);
827	}
828#endif
829	// Hang forever
830	gb->memory.ime = 0;
831	--cpu->pc;
832}
833
834bool GBIsROM(struct VFile* vf) {
835	if (!vf) {
836		return false;
837	}
838	vf->seek(vf, 0x104, SEEK_SET);
839	uint8_t header[4];
840
841	if (vf->read(vf, &header, sizeof(header)) < (ssize_t) sizeof(header)) {
842		return false;
843	}
844	if (memcmp(header, _knownHeader, sizeof(header))) {
845		return false;
846	}
847	return true;
848}
849
850void GBGetGameTitle(const struct GB* gb, char* out) {
851	const struct GBCartridge* cart = NULL;
852	if (gb->memory.rom) {
853		cart = (const struct GBCartridge*) &gb->memory.rom[0x100];
854	}
855	if (!cart) {
856		return;
857	}
858	if (cart->oldLicensee != 0x33) {
859		memcpy(out, cart->titleLong, 16);
860	} else {
861		memcpy(out, cart->titleShort, 11);
862	}
863}
864
865void GBGetGameCode(const struct GB* gb, char* out) {
866	memset(out, 0, 8);
867	const struct GBCartridge* cart = NULL;
868	if (gb->memory.rom) {
869		cart = (const struct GBCartridge*) &gb->memory.rom[0x100];
870	}
871	if (!cart) {
872		return;
873	}
874	if (cart->cgb == 0xC0) {
875		memcpy(out, "CGB-????", 8);
876	} else {
877		memcpy(out, "DMG-????", 8);
878	}
879	if (cart->oldLicensee == 0x33) {
880		memcpy(&out[4], cart->maker, 4);
881	}
882}
883
884void GBFrameStarted(struct GB* gb) {
885	GBTestKeypadIRQ(gb);
886
887	size_t c;
888	for (c = 0; c < mCoreCallbacksListSize(&gb->coreCallbacks); ++c) {
889		struct mCoreCallbacks* callbacks = mCoreCallbacksListGetPointer(&gb->coreCallbacks, c);
890		if (callbacks->videoFrameStarted) {
891			callbacks->videoFrameStarted(callbacks->context);
892		}
893	}
894}
895
896void GBFrameEnded(struct GB* gb) {
897	GBSramClean(gb, gb->video.frameCounter);
898
899	if (gb->cpu->components && gb->cpu->components[CPU_COMPONENT_CHEAT_DEVICE]) {
900		struct mCheatDevice* device = (struct mCheatDevice*) gb->cpu->components[CPU_COMPONENT_CHEAT_DEVICE];
901		size_t i;
902		for (i = 0; i < mCheatSetsSize(&device->cheats); ++i) {
903			struct mCheatSet* cheats = *mCheatSetsGetPointer(&device->cheats, i);
904			mCheatRefresh(device, cheats);
905		}
906	}
907
908	// TODO: Move to common code
909	if (gb->stream && gb->stream->postVideoFrame) {
910		const color_t* pixels;
911		size_t stride;
912		gb->video.renderer->getPixels(gb->video.renderer, &stride, (const void**) &pixels);
913		gb->stream->postVideoFrame(gb->stream, pixels, stride);
914	}
915
916	size_t c;
917	for (c = 0; c < mCoreCallbacksListSize(&gb->coreCallbacks); ++c) {
918		struct mCoreCallbacks* callbacks = mCoreCallbacksListGetPointer(&gb->coreCallbacks, c);
919		if (callbacks->videoFrameEnded) {
920			callbacks->videoFrameEnded(callbacks->context);
921		}
922	}
923}
924
925enum GBModel GBNameToModel(const char* model) {
926	if (strcasecmp(model, "DMG") == 0) {
927		return GB_MODEL_DMG;
928	} else if (strcasecmp(model, "CGB") == 0) {
929		return GB_MODEL_CGB;
930	} else if (strcasecmp(model, "AGB") == 0) {
931		return GB_MODEL_AGB;
932	} else if (strcasecmp(model, "SGB") == 0) {
933		return GB_MODEL_SGB;
934	} else if (strcasecmp(model, "MGB") == 0) {
935		return GB_MODEL_MGB;
936	} else if (strcasecmp(model, "SGB2") == 0) {
937		return GB_MODEL_SGB2;
938	}
939	return GB_MODEL_AUTODETECT;
940}
941
942const char* GBModelToName(enum GBModel model) {
943	switch (model) {
944	case GB_MODEL_DMG:
945		return "DMG";
946	case GB_MODEL_SGB:
947		return "SGB";
948	case GB_MODEL_MGB:
949		return "MGB";
950	case GB_MODEL_SGB2:
951		return "SGB2";
952	case GB_MODEL_CGB:
953		return "CGB";
954	case GB_MODEL_AGB:
955		return "AGB";
956	default:
957	case GB_MODEL_AUTODETECT:
958		return NULL;
959	}
960}