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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/lr35902/lr35902.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_LR35902_FREQUENCY = 0x800000;
 23const uint32_t SGB_LR35902_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 CGB_BIOS_CHECKSUM 0x41884E46
 34
 35mLOG_DEFINE_CATEGORY(GB, "GB", "gb");
 36
 37static void GBInit(void* cpu, struct mCPUComponent* component);
 38static void GBDeinit(struct mCPUComponent* component);
 39static void GBInterruptHandlerInit(struct LR35902InterruptHandler* irqh);
 40static void GBProcessEvents(struct LR35902Core* cpu);
 41static void GBSetInterrupts(struct LR35902Core* cpu, bool enable);
 42static uint16_t GBIRQVector(struct LR35902Core* cpu);
 43static void GBIllegal(struct LR35902Core* cpu);
 44static void GBStop(struct LR35902Core* cpu);
 45
 46static void _enableInterrupts(struct mTiming* timing, void* user, uint32_t cyclesLate);
 47
 48#ifdef FIXED_ROM_BUFFER
 49extern uint32_t* romBuffer;
 50extern size_t romBufferSize;
 51#endif
 52
 53void GBCreate(struct GB* gb) {
 54	gb->d.id = GB_COMPONENT_MAGIC;
 55	gb->d.init = GBInit;
 56	gb->d.deinit = GBDeinit;
 57}
 58
 59static void GBInit(void* cpu, struct mCPUComponent* component) {
 60	struct GB* gb = (struct GB*) component;
 61	gb->cpu = cpu;
 62	gb->sync = NULL;
 63
 64	GBInterruptHandlerInit(&gb->cpu->irqh);
 65	GBMemoryInit(gb);
 66
 67	gb->video.p = gb;
 68	GBVideoInit(&gb->video);
 69
 70	gb->audio.p = gb;
 71	GBAudioInit(&gb->audio, 2048, &gb->memory.io[REG_NR52], GB_AUDIO_DMG); // TODO: Remove magic constant
 72
 73	gb->sio.p = gb;
 74	GBSIOInit(&gb->sio);
 75
 76	gb->timer.p = gb;
 77
 78	gb->model = GB_MODEL_AUTODETECT;
 79
 80	gb->biosVf = NULL;
 81	gb->romVf = NULL;
 82	gb->sramVf = NULL;
 83	gb->sramRealVf = NULL;
 84
 85	gb->isPristine = false;
 86	gb->pristineRomSize = 0;
 87	gb->yankedRomSize = 0;
 88
 89	mCoreCallbacksListInit(&gb->coreCallbacks, 0);
 90	gb->stream = NULL;
 91
 92	mTimingInit(&gb->timing, &gb->cpu->cycles, &gb->cpu->nextEvent);
 93	gb->audio.timing = &gb->timing;
 94
 95	gb->eiPending.name = "GB EI";
 96	gb->eiPending.callback = _enableInterrupts;
 97	gb->eiPending.context = gb;
 98	gb->eiPending.priority = 0;
 99}
100
101static void GBDeinit(struct mCPUComponent* component) {
102	struct GB* gb = (struct GB*) component;
103	mTimingDeinit(&gb->timing);
104}
105
106bool GBLoadROM(struct GB* gb, struct VFile* vf) {
107	if (!vf) {
108		return false;
109	}
110	GBUnloadROM(gb);
111	gb->romVf = vf;
112	gb->pristineRomSize = vf->size(vf);
113	vf->seek(vf, 0, SEEK_SET);
114	gb->isPristine = true;
115#ifdef FIXED_ROM_BUFFER
116	if (gb->pristineRomSize <= romBufferSize) {
117		gb->memory.rom = romBuffer;
118		vf->read(vf, romBuffer, gb->pristineRomSize);
119	}
120#else
121	gb->memory.rom = vf->map(vf, gb->pristineRomSize, MAP_READ);
122#endif
123	if (!gb->memory.rom) {
124		return false;
125	}
126	gb->yankedRomSize = 0;
127	gb->memory.romBase = gb->memory.rom;
128	gb->memory.romSize = gb->pristineRomSize;
129	gb->romCrc32 = doCrc32(gb->memory.rom, gb->memory.romSize);
130	GBMBCInit(gb);
131
132	if (gb->cpu) {
133		struct LR35902Core* cpu = gb->cpu;
134		cpu->memory.setActiveRegion(cpu, cpu->pc);
135	}
136
137	// TODO: error check
138	return true;
139}
140
141static void GBSramDeinit(struct GB* gb) {
142	if (gb->sramVf) {
143		gb->sramVf->unmap(gb->sramVf, gb->memory.sram, gb->sramSize);
144		if (gb->memory.mbcType == GB_MBC3_RTC && gb->sramVf == gb->sramRealVf) {
145			GBMBCRTCWrite(gb);
146		}
147		gb->sramVf = NULL;
148	} else if (gb->memory.sram) {
149		mappedMemoryFree(gb->memory.sram, gb->sramSize);
150	}
151	gb->memory.sram = 0;
152}
153
154bool GBLoadSave(struct GB* gb, struct VFile* vf) {
155	GBSramDeinit(gb);
156	gb->sramVf = vf;
157	gb->sramRealVf = vf;
158	if (gb->sramSize) {
159		GBResizeSram(gb, gb->sramSize);
160	}
161	return vf;
162}
163
164void GBResizeSram(struct GB* gb, size_t size) {
165	if (gb->memory.sram && size <= gb->sramSize) {
166		return;
167	}
168	struct VFile* vf = gb->sramVf;
169	if (vf) {
170		if (vf == gb->sramRealVf) {
171			ssize_t vfSize = vf->size(vf);
172			if (vfSize >= 0 && (size_t) vfSize < size) {
173				uint8_t extdataBuffer[0x100];
174				if (vfSize & 0xFF) {
175					vf->seek(vf, -(vfSize & 0xFF), SEEK_END);
176					vf->read(vf, extdataBuffer, vfSize & 0xFF);
177				}
178				if (gb->memory.sram) {
179					vf->unmap(vf, gb->memory.sram, gb->sramSize);
180				}
181				vf->truncate(vf, size + (vfSize & 0xFF));
182				if (vfSize & 0xFF) {
183					vf->seek(vf, size, SEEK_SET);
184					vf->write(vf, extdataBuffer, vfSize & 0xFF);
185				}
186				gb->memory.sram = vf->map(vf, size, MAP_WRITE);
187				memset(&gb->memory.sram[gb->sramSize], 0xFF, size - gb->sramSize);
188			} else if (size > gb->sramSize || !gb->memory.sram) {
189				if (gb->memory.sram) {
190					vf->unmap(vf, gb->memory.sram, gb->sramSize);
191				}
192				gb->memory.sram = vf->map(vf, size, MAP_WRITE);
193			}
194		} else {
195			if (gb->memory.sram) {
196				vf->unmap(vf, gb->memory.sram, gb->sramSize);
197			}
198			gb->memory.sram = vf->map(vf, size, MAP_READ);
199		}
200		if (gb->memory.sram == (void*) -1) {
201			gb->memory.sram = NULL;
202		}
203	} else {
204		uint8_t* newSram = anonymousMemoryMap(size);
205		if (gb->memory.sram) {
206			if (size > gb->sramSize) {
207				memcpy(newSram, gb->memory.sram, gb->sramSize);
208				memset(&newSram[gb->sramSize], 0xFF, size - gb->sramSize);
209			} else {
210				memcpy(newSram, gb->memory.sram, size);
211			}
212			mappedMemoryFree(gb->memory.sram, gb->sramSize);
213		} else {
214			memset(newSram, 0xFF, size);
215		}
216		gb->memory.sram = newSram;
217	}
218	if (gb->sramSize < size) {
219		gb->sramSize = size;
220	}
221}
222
223void GBSramClean(struct GB* gb, uint32_t frameCount) {
224	// TODO: Share with GBASavedataClean
225	if (!gb->sramVf) {
226		return;
227	}
228	if (gb->sramDirty & GB_SRAM_DIRT_NEW) {
229		gb->sramDirtAge = frameCount;
230		gb->sramDirty &= ~GB_SRAM_DIRT_NEW;
231		if (!(gb->sramDirty & GB_SRAM_DIRT_SEEN)) {
232			gb->sramDirty |= GB_SRAM_DIRT_SEEN;
233		}
234	} else if ((gb->sramDirty & GB_SRAM_DIRT_SEEN) && frameCount - gb->sramDirtAge > CLEANUP_THRESHOLD) {
235		if (gb->sramMaskWriteback) {
236			GBSavedataUnmask(gb);
237		}
238		if (gb->memory.mbcType == GB_MBC3_RTC) {
239			GBMBCRTCWrite(gb);
240		}
241		gb->sramDirty = 0;
242		if (gb->memory.sram && gb->sramVf->sync(gb->sramVf, gb->memory.sram, gb->sramSize)) {
243			mLOG(GB_MEM, INFO, "Savedata synced");
244		} else {
245			mLOG(GB_MEM, INFO, "Savedata failed to sync!");
246		}
247	}
248}
249
250void GBSavedataMask(struct GB* gb, struct VFile* vf, bool writeback) {
251	GBSramDeinit(gb);
252	gb->sramVf = vf;
253	gb->sramMaskWriteback = writeback;
254	gb->memory.sram = vf->map(vf, gb->sramSize, MAP_READ);
255	GBMBCSwitchSramBank(gb, gb->memory.sramCurrentBank);
256}
257
258void GBSavedataUnmask(struct GB* gb) {
259	if (gb->sramVf == gb->sramRealVf) {
260		return;
261	}
262	struct VFile* vf = gb->sramVf;
263	GBSramDeinit(gb);
264	gb->sramVf = gb->sramRealVf;
265	gb->memory.sram = gb->sramVf->map(gb->sramVf, gb->sramSize, MAP_WRITE);
266	if (gb->sramMaskWriteback) {
267		vf->seek(vf, 0, SEEK_SET);
268		vf->read(vf, gb->memory.sram, gb->sramSize);
269		gb->sramMaskWriteback = false;
270	}
271	vf->close(vf);
272}
273
274void GBUnloadROM(struct GB* gb) {
275	// TODO: Share with GBAUnloadROM
276	if (gb->memory.rom && gb->memory.romBase != gb->memory.rom && !gb->isPristine) {
277		free(gb->memory.romBase);
278	}
279	if (gb->memory.rom && !gb->isPristine) {
280		if (gb->yankedRomSize) {
281			gb->yankedRomSize = 0;
282		}
283		mappedMemoryFree(gb->memory.rom, GB_SIZE_CART_MAX);
284	}
285
286	if (gb->romVf) {
287#ifndef FIXED_ROM_BUFFER
288		gb->romVf->unmap(gb->romVf, gb->memory.rom, gb->pristineRomSize);
289#endif
290		gb->romVf->close(gb->romVf);
291		gb->romVf = NULL;
292	}
293	gb->memory.rom = NULL;
294	gb->memory.mbcType = GB_MBC_AUTODETECT;
295	gb->isPristine = false;
296
297	gb->sramMaskWriteback = false;
298	GBSavedataUnmask(gb);
299	GBSramDeinit(gb);
300	if (gb->sramRealVf) {
301		gb->sramRealVf->close(gb->sramRealVf);
302	}
303	gb->sramRealVf = NULL;
304	gb->sramVf = NULL;
305	if (gb->memory.cam && gb->memory.cam->stopRequestImage) {
306		gb->memory.cam->stopRequestImage(gb->memory.cam);
307	}
308}
309
310void GBSynthesizeROM(struct VFile* vf) {
311	if (!vf) {
312		return;
313	}
314	const struct GBCartridge cart = {
315		.logo = { _knownHeader[0], _knownHeader[1], _knownHeader[2], _knownHeader[3]}
316	};
317
318	vf->seek(vf, 0x100, SEEK_SET);
319	vf->write(vf, &cart, sizeof(cart));
320}
321
322void GBLoadBIOS(struct GB* gb, struct VFile* vf) {
323	gb->biosVf = vf;
324}
325
326void GBApplyPatch(struct GB* gb, struct Patch* patch) {
327	size_t patchedSize = patch->outputSize(patch, gb->memory.romSize);
328	if (!patchedSize) {
329		return;
330	}
331	if (patchedSize > GB_SIZE_CART_MAX) {
332		patchedSize = GB_SIZE_CART_MAX;
333	}
334	void* newRom = anonymousMemoryMap(GB_SIZE_CART_MAX);
335	if (!patch->applyPatch(patch, gb->memory.rom, gb->pristineRomSize, newRom, patchedSize)) {
336		mappedMemoryFree(newRom, GB_SIZE_CART_MAX);
337		return;
338	}
339	if (gb->romVf) {
340#ifndef FIXED_ROM_BUFFER
341		gb->romVf->unmap(gb->romVf, gb->memory.rom, gb->pristineRomSize);
342#endif
343		gb->romVf->close(gb->romVf);
344		gb->romVf = NULL;
345	}
346	gb->isPristine = false;
347	if (gb->memory.romBase == gb->memory.rom) {
348		gb->memory.romBase = newRom;
349	}
350	gb->memory.rom = newRom;
351	gb->memory.romSize = patchedSize;
352	gb->romCrc32 = doCrc32(gb->memory.rom, gb->memory.romSize);
353	gb->cpu->memory.setActiveRegion(gb->cpu, gb->cpu->pc);
354}
355
356void GBDestroy(struct GB* gb) {
357	GBUnloadROM(gb);
358
359	if (gb->biosVf) {
360		gb->biosVf->close(gb->biosVf);
361		gb->biosVf = 0;
362	}
363
364	GBMemoryDeinit(gb);
365	GBAudioDeinit(&gb->audio);
366	GBVideoDeinit(&gb->video);
367	GBSIODeinit(&gb->sio);
368	mCoreCallbacksListDeinit(&gb->coreCallbacks);
369}
370
371void GBInterruptHandlerInit(struct LR35902InterruptHandler* irqh) {
372	irqh->reset = GBReset;
373	irqh->processEvents = GBProcessEvents;
374	irqh->setInterrupts = GBSetInterrupts;
375	irqh->irqVector = GBIRQVector;
376	irqh->hitIllegal = GBIllegal;
377	irqh->stop = GBStop;
378	irqh->halt = GBHalt;
379}
380
381static uint32_t _GBBiosCRC32(struct VFile* vf) {
382	ssize_t size = vf->size(vf);
383	if (size <= 0 || size > GB_SIZE_CART_BANK0) {
384		return 0;
385	}
386	void* bios = vf->map(vf, size, MAP_READ);
387	uint32_t biosCrc = doCrc32(bios, size);
388	vf->unmap(vf, bios, size);
389	return biosCrc;
390}
391
392bool GBIsBIOS(struct VFile* vf) {
393	switch (_GBBiosCRC32(vf)) {
394	case DMG_BIOS_CHECKSUM:
395	case DMG_2_BIOS_CHECKSUM:
396	case MGB_BIOS_CHECKSUM:
397	case SGB_BIOS_CHECKSUM:
398	case CGB_BIOS_CHECKSUM:
399		return true;
400	default:
401		return false;
402	}
403}
404
405void GBReset(struct LR35902Core* cpu) {
406	struct GB* gb = (struct GB*) cpu->master;
407	gb->memory.romBase = gb->memory.rom;
408	GBDetectModel(gb);
409
410	if (gb->biosVf) {
411		if (!GBIsBIOS(gb->biosVf)) {
412			gb->biosVf->close(gb->biosVf);
413			gb->biosVf = NULL;
414		} else {
415			gb->biosVf->seek(gb->biosVf, 0, SEEK_SET);
416			gb->memory.romBase = malloc(GB_SIZE_CART_BANK0);
417			ssize_t size = gb->biosVf->read(gb->biosVf, gb->memory.romBase, GB_SIZE_CART_BANK0);
418			memcpy(&gb->memory.romBase[size], &gb->memory.rom[size], GB_SIZE_CART_BANK0 - size);
419			if (size > 0x100) {
420				memcpy(&gb->memory.romBase[0x100], &gb->memory.rom[0x100], sizeof(struct GBCartridge));
421			}
422
423			cpu->a = 0;
424			cpu->f.packed = 0;
425			cpu->c = 0;
426			cpu->e = 0;
427			cpu->h = 0;
428			cpu->l = 0;
429			cpu->sp = 0;
430			cpu->pc = 0;
431		}
432	}
433
434	cpu->b = 0;
435	cpu->d = 0;
436
437	gb->timer.internalDiv = 0;
438
439	gb->cpuBlocked = false;
440	gb->earlyExit = false;
441	gb->doubleSpeed = 0;
442
443	if (gb->yankedRomSize) {
444		gb->memory.romSize = gb->yankedRomSize;
445		gb->yankedRomSize = 0;
446	}
447
448	gb->sgbBit = -1;
449	gb->sgbControllers = 0;
450	gb->sgbCurrentController = 0;
451	gb->currentSgbBits = 0;
452	memset(gb->sgbPacket, 0, sizeof(gb->sgbPacket));
453
454	mTimingClear(&gb->timing);
455
456	GBMemoryReset(gb);
457	GBVideoReset(&gb->video);
458	GBTimerReset(&gb->timer);
459	if (!gb->biosVf) {
460		GBSkipBIOS(gb);
461	} else {
462		mTimingSchedule(&gb->timing, &gb->timer.event, 0);
463	}
464
465	GBIOReset(gb);
466	GBAudioReset(&gb->audio);
467	GBSIOReset(&gb->sio);
468
469	cpu->memory.setActiveRegion(cpu, cpu->pc);
470
471	GBSavedataUnmask(gb);
472}
473
474void GBSkipBIOS(struct GB* gb) {
475	struct LR35902Core* cpu = gb->cpu;
476	int nextDiv = 0;
477
478	switch (gb->model) {
479	case GB_MODEL_AUTODETECT: // Silence warnings
480		gb->model = GB_MODEL_DMG;
481	case GB_MODEL_DMG:
482		cpu->a = 1;
483		cpu->f.packed = 0xB0;
484		cpu->c = 0x13;
485		cpu->e = 0xD8;
486		cpu->h = 1;
487		cpu->l = 0x4D;
488		gb->timer.internalDiv = 0xABC;
489		nextDiv = 4;
490		break;
491	case GB_MODEL_SGB:
492		cpu->a = 1;
493		cpu->f.packed = 0x00;
494		cpu->c = 0x14;
495		cpu->e = 0x00;
496		cpu->h = 0xC0;
497		cpu->l = 0x60;
498		gb->timer.internalDiv = 0xABC;
499		nextDiv = 4;
500		break;
501	case GB_MODEL_MGB:
502		cpu->a = 0xFF;
503		cpu->f.packed = 0xB0;
504		cpu->c = 0x13;
505		cpu->e = 0xD8;
506		cpu->h = 1;
507		cpu->l = 0x4D;
508		gb->timer.internalDiv = 0xABC;
509		nextDiv = 4;
510		break;
511	case GB_MODEL_SGB2:
512		cpu->a = 0xFF;
513		cpu->f.packed = 0x00;
514		cpu->c = 0x14;
515		cpu->e = 0x00;
516		cpu->h = 0xC0;
517		cpu->l = 0x60;
518		gb->timer.internalDiv = 0xABC;
519		nextDiv = 4;
520		break;
521	case GB_MODEL_AGB:
522		cpu->a = 0x11;
523		cpu->b = 1;
524		cpu->f.packed = 0x00;
525		cpu->c = 0;
526		cpu->e = 0x08;
527		cpu->h = 0;
528		cpu->l = 0x7C;
529		gb->timer.internalDiv = 0x1EA;
530		nextDiv = 0xC;
531		break;
532	case GB_MODEL_CGB:
533		cpu->a = 0x11;
534		cpu->f.packed = 0x80;
535		cpu->c = 0;
536		cpu->e = 0x08;
537		cpu->h = 0;
538		cpu->l = 0x7C;
539		gb->timer.internalDiv = 0x1EA;
540		nextDiv = 0xC;
541		break;
542	}
543
544	cpu->sp = 0xFFFE;
545	cpu->pc = 0x100;
546
547	mTimingDeschedule(&gb->timing, &gb->timer.event);
548	mTimingSchedule(&gb->timing, &gb->timer.event, 0);
549
550	if (gb->biosVf) {
551		GBUnmapBIOS(gb);
552	}
553}
554
555void GBUnmapBIOS(struct GB* gb) {
556	if (gb->memory.romBase < gb->memory.rom || gb->memory.romBase > &gb->memory.rom[gb->memory.romSize - 1]) {
557		free(gb->memory.romBase);
558		gb->memory.romBase = gb->memory.rom;
559	}
560	// XXX: Force AGB registers for AGB-mode
561	if (gb->model == GB_MODEL_AGB && gb->cpu->pc == 0x100) {
562		gb->cpu->b = 1;
563	}
564}
565
566void GBDetectModel(struct GB* gb) {
567	if (gb->model != GB_MODEL_AUTODETECT) {
568		return;
569	}
570	if (gb->biosVf) {
571		switch (_GBBiosCRC32(gb->biosVf)) {
572		case DMG_BIOS_CHECKSUM:
573		case DMG_2_BIOS_CHECKSUM:
574			gb->model = GB_MODEL_DMG;
575			break;
576		case MGB_BIOS_CHECKSUM:
577			gb->model = GB_MODEL_MGB;
578			break;
579		case SGB_BIOS_CHECKSUM:
580			gb->model = GB_MODEL_SGB;
581			break;
582		case CGB_BIOS_CHECKSUM:
583			gb->model = GB_MODEL_CGB;
584			break;
585		default:
586			gb->biosVf->close(gb->biosVf);
587			gb->biosVf = NULL;
588		}
589	}
590	if (gb->model == GB_MODEL_AUTODETECT && gb->memory.rom) {
591		const struct GBCartridge* cart = (const struct GBCartridge*) &gb->memory.rom[0x100];
592		if (cart->cgb & 0x80) {
593			gb->model = GB_MODEL_CGB;
594		} else if (cart->sgb == 0x03 && cart->oldLicensee == 0x33) {
595			gb->model = GB_MODEL_SGB;
596		} else {
597			gb->model = GB_MODEL_DMG;
598		}
599	}
600
601	switch (gb->model) {
602	case GB_MODEL_DMG:
603	case GB_MODEL_SGB:
604	case GB_MODEL_AUTODETECT: //Silence warnings
605		gb->audio.style = GB_AUDIO_DMG;
606		break;
607	case GB_MODEL_MGB:
608	case GB_MODEL_SGB2:
609		gb->audio.style = GB_AUDIO_MGB;
610		break;
611	case GB_MODEL_AGB:
612	case GB_MODEL_CGB:
613		gb->audio.style = GB_AUDIO_CGB;
614		break;
615	}
616}
617
618void GBUpdateIRQs(struct GB* gb) {
619	int irqs = gb->memory.ie & gb->memory.io[REG_IF];
620	if (!irqs) {
621		gb->cpu->irqPending = false;
622		return;
623	}
624	gb->cpu->halted = false;
625
626	if (!gb->memory.ime || gb->cpu->irqPending) {
627		return;
628	}
629	LR35902RaiseIRQ(gb->cpu);
630}
631
632void GBProcessEvents(struct LR35902Core* cpu) {
633	struct GB* gb = (struct GB*) cpu->master;
634	do {
635		int32_t cycles = cpu->cycles;
636		int32_t nextEvent;
637
638		cpu->cycles = 0;
639		cpu->nextEvent = INT_MAX;
640
641		nextEvent = cycles;
642		do {
643			nextEvent = mTimingTick(&gb->timing, nextEvent);
644		} while (gb->cpuBlocked);
645		cpu->nextEvent = nextEvent;
646
647		if (gb->earlyExit) {
648			gb->earlyExit = false;
649			break;
650		}
651		if (cpu->halted) {
652			cpu->cycles = cpu->nextEvent;
653			if (!gb->memory.ie || !gb->memory.ime) {
654				break;
655			}
656		}
657	} while (cpu->cycles >= cpu->nextEvent);
658}
659
660void GBSetInterrupts(struct LR35902Core* cpu, bool enable) {
661	struct GB* gb = (struct GB*) cpu->master;
662	if (!enable) {
663		gb->memory.ime = enable;
664		mTimingDeschedule(&gb->timing, &gb->eiPending);
665		GBUpdateIRQs(gb);
666	} else {
667		mTimingDeschedule(&gb->timing, &gb->eiPending);
668		mTimingSchedule(&gb->timing, &gb->eiPending, 4);
669	}
670}
671
672uint16_t GBIRQVector(struct LR35902Core* cpu) {
673	struct GB* gb = (struct GB*) cpu->master;
674	int irqs = gb->memory.ie & gb->memory.io[REG_IF];
675
676	if (irqs & (1 << GB_IRQ_VBLANK)) {
677		gb->memory.io[REG_IF] &= ~(1 << GB_IRQ_VBLANK);
678		return GB_VECTOR_VBLANK;
679	}
680	if (irqs & (1 << GB_IRQ_LCDSTAT)) {
681		gb->memory.io[REG_IF] &= ~(1 << GB_IRQ_LCDSTAT);
682		return GB_VECTOR_LCDSTAT;
683	}
684	if (irqs & (1 << GB_IRQ_TIMER)) {
685		gb->memory.io[REG_IF] &= ~(1 << GB_IRQ_TIMER);
686		return GB_VECTOR_TIMER;
687	}
688	if (irqs & (1 << GB_IRQ_SIO)) {
689		gb->memory.io[REG_IF] &= ~(1 << GB_IRQ_SIO);
690		return GB_VECTOR_SIO;
691	}
692	if (irqs & (1 << GB_IRQ_KEYPAD)) {
693		gb->memory.io[REG_IF] &= ~(1 << GB_IRQ_KEYPAD);
694		return GB_VECTOR_KEYPAD;
695	}
696	return 0;
697}
698
699static void _enableInterrupts(struct mTiming* timing, void* user, uint32_t cyclesLate) {
700	UNUSED(timing);
701	UNUSED(cyclesLate);
702	struct GB* gb = user;
703	gb->memory.ime = true;
704	GBUpdateIRQs(gb);
705}
706
707void GBHalt(struct LR35902Core* cpu) {
708	struct GB* gb = (struct GB*) cpu->master;
709	if (!(gb->memory.ie & gb->memory.io[REG_IF])) {
710		cpu->cycles = cpu->nextEvent;
711		cpu->halted = true;
712	} else if (gb->model < GB_MODEL_CGB) {
713		mLOG(GB, STUB, "Unimplemented HALT bug");
714	}
715}
716
717void GBStop(struct LR35902Core* cpu) {
718	struct GB* gb = (struct GB*) cpu->master;
719	if (cpu->bus) {
720		mLOG(GB, GAME_ERROR, "Hit illegal stop at address %04X:%02X", cpu->pc, cpu->bus);
721	}
722	if (gb->memory.io[REG_KEY1] & 1) {
723		gb->doubleSpeed ^= 1;
724		gb->audio.timingFactor = gb->doubleSpeed + 1;
725		gb->memory.io[REG_KEY1] = 0;
726		gb->memory.io[REG_KEY1] |= gb->doubleSpeed << 7;
727	} else if (cpu->bus) {
728#ifdef USE_DEBUGGERS
729		if (cpu->components && cpu->components[CPU_COMPONENT_DEBUGGER]) {
730			struct mDebuggerEntryInfo info = {
731				.address = cpu->pc - 1,
732				.type.bp.opcode = 0x1000 | cpu->bus
733			};
734			mDebuggerEnter((struct mDebugger*) cpu->components[CPU_COMPONENT_DEBUGGER], DEBUGGER_ENTER_ILLEGAL_OP, &info);
735		}
736#endif
737		// Hang forever
738		gb->memory.ime = 0;
739		cpu->pc -= 2;
740	}
741	// TODO: Actually stop
742}
743
744void GBIllegal(struct LR35902Core* cpu) {
745	struct GB* gb = (struct GB*) cpu->master;
746	mLOG(GB, GAME_ERROR, "Hit illegal opcode at address %04X:%02X", cpu->pc, cpu->bus);
747#ifdef USE_DEBUGGERS
748	if (cpu->components && cpu->components[CPU_COMPONENT_DEBUGGER]) {
749		struct mDebuggerEntryInfo info = {
750			.address = cpu->pc,
751			.type.bp.opcode = cpu->bus
752		};
753		mDebuggerEnter((struct mDebugger*) cpu->components[CPU_COMPONENT_DEBUGGER], DEBUGGER_ENTER_ILLEGAL_OP, &info);
754	}
755#endif
756	// Hang forever
757	gb->memory.ime = 0;
758	--cpu->pc;
759}
760
761bool GBIsROM(struct VFile* vf) {
762	if (!vf) {
763		return false;
764	}
765	vf->seek(vf, 0x104, SEEK_SET);
766	uint8_t header[4];
767
768	if (vf->read(vf, &header, sizeof(header)) < (ssize_t) sizeof(header)) {
769		return false;
770	}
771	if (memcmp(header, _knownHeader, sizeof(header))) {
772		return false;
773	}
774	return true;
775}
776
777void GBGetGameTitle(const struct GB* gb, char* out) {
778	const struct GBCartridge* cart = NULL;
779	if (gb->memory.rom) {
780		cart = (const struct GBCartridge*) &gb->memory.rom[0x100];
781	}
782	if (!cart) {
783		return;
784	}
785	if (cart->oldLicensee != 0x33) {
786		memcpy(out, cart->titleLong, 16);
787	} else {
788		memcpy(out, cart->titleShort, 11);
789	}
790}
791
792void GBGetGameCode(const struct GB* gb, char* out) {
793	memset(out, 0, 8);
794	const struct GBCartridge* cart = NULL;
795	if (gb->memory.rom) {
796		cart = (const struct GBCartridge*) &gb->memory.rom[0x100];
797	}
798	if (!cart) {
799		return;
800	}
801	if (cart->cgb == 0xC0) {
802		memcpy(out, "CGB-????", 8);
803	} else {
804		memcpy(out, "DMG-????", 8);
805	}
806	if (cart->oldLicensee == 0x33) {
807		memcpy(&out[4], cart->maker, 4);
808	}
809}
810
811void GBFrameEnded(struct GB* gb) {
812	GBSramClean(gb, gb->video.frameCounter);
813
814	if (gb->cpu->components && gb->cpu->components[CPU_COMPONENT_CHEAT_DEVICE]) {
815		struct mCheatDevice* device = (struct mCheatDevice*) gb->cpu->components[CPU_COMPONENT_CHEAT_DEVICE];
816		size_t i;
817		for (i = 0; i < mCheatSetsSize(&device->cheats); ++i) {
818			struct mCheatSet* cheats = *mCheatSetsGetPointer(&device->cheats, i);
819			mCheatRefresh(device, cheats);
820		}
821	}
822
823	GBTestKeypadIRQ(gb);
824}
825
826enum GBModel GBNameToModel(const char* model) {
827	if (strcasecmp(model, "DMG") == 0) {
828		return GB_MODEL_DMG;
829	} else if (strcasecmp(model, "CGB") == 0) {
830		return GB_MODEL_CGB;
831	} else if (strcasecmp(model, "AGB") == 0) {
832		return GB_MODEL_AGB;
833	} else if (strcasecmp(model, "SGB") == 0) {
834		return GB_MODEL_SGB;
835	} else if (strcasecmp(model, "MGB") == 0) {
836		return GB_MODEL_MGB;
837	} else if (strcasecmp(model, "SGB2") == 0) {
838		return GB_MODEL_SGB2;
839	}
840	return GB_MODEL_AUTODETECT;
841}
842
843const char* GBModelToName(enum GBModel model) {
844	switch (model) {
845	case GB_MODEL_DMG:
846		return "DMG";
847	case GB_MODEL_SGB:
848		return "SGB";
849	case GB_MODEL_MGB:
850		return "MGB";
851	case GB_MODEL_SGB2:
852		return "SGB2";
853	case GB_MODEL_CGB:
854		return "CGB";
855	case GB_MODEL_AGB:
856		return "AGB";
857	default:
858	case GB_MODEL_AUTODETECT:
859		return NULL;
860	}
861}