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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 CGB_BIOS_CHECKSUM 0x41884E46
 32
 33mLOG_DEFINE_CATEGORY(GB, "GB");
 34
 35static void GBInit(void* cpu, struct mCPUComponent* component);
 36static void GBDeinit(struct mCPUComponent* component);
 37static void GBInterruptHandlerInit(struct LR35902InterruptHandler* irqh);
 38static void GBProcessEvents(struct LR35902Core* cpu);
 39static void GBSetInterrupts(struct LR35902Core* cpu, bool enable);
 40static void GBIllegal(struct LR35902Core* cpu);
 41static void GBStop(struct LR35902Core* cpu);
 42
 43static void _enableInterrupts(struct mTiming* timing, void* user, uint32_t cyclesLate);
 44
 45#ifdef _3DS
 46extern uint32_t* romBuffer;
 47extern size_t romBufferSize;
 48#endif
 49
 50void GBCreate(struct GB* gb) {
 51	gb->d.id = GB_COMPONENT_MAGIC;
 52	gb->d.init = GBInit;
 53	gb->d.deinit = GBDeinit;
 54}
 55
 56static void GBInit(void* cpu, struct mCPUComponent* component) {
 57	struct GB* gb = (struct GB*) component;
 58	gb->cpu = cpu;
 59	gb->sync = NULL;
 60
 61	GBInterruptHandlerInit(&gb->cpu->irqh);
 62	GBMemoryInit(gb);
 63
 64	gb->video.p = gb;
 65	GBVideoInit(&gb->video);
 66
 67	gb->audio.p = gb;
 68	GBAudioInit(&gb->audio, 2048, &gb->memory.io[REG_NR52], GB_AUDIO_DMG); // TODO: Remove magic constant
 69
 70	gb->sio.p = gb;
 71	GBSIOInit(&gb->sio);
 72
 73	gb->timer.p = gb;
 74
 75	gb->model = GB_MODEL_AUTODETECT;
 76
 77	gb->biosVf = NULL;
 78	gb->romVf = NULL;
 79	gb->sramVf = NULL;
 80	gb->sramRealVf = NULL;
 81
 82	gb->isPristine = false;
 83	gb->pristineRomSize = 0;
 84	gb->yankedRomSize = 0;
 85
 86	mCoreCallbacksListInit(&gb->coreCallbacks, 0);
 87	gb->stream = NULL;
 88
 89	mTimingInit(&gb->timing, &gb->cpu->cycles, &gb->cpu->nextEvent);
 90	gb->audio.timing = &gb->timing;
 91
 92	gb->eiPending.name = "GB EI";
 93	gb->eiPending.callback = _enableInterrupts;
 94	gb->eiPending.context = gb;
 95	gb->eiPending.priority = 0;
 96}
 97
 98static void GBDeinit(struct mCPUComponent* component) {
 99	struct GB* gb = (struct GB*) component;
100	mTimingDeinit(&gb->timing);
101}
102
103bool GBLoadROM(struct GB* gb, struct VFile* vf) {
104	if (!vf) {
105		return false;
106	}
107	GBUnloadROM(gb);
108	gb->romVf = vf;
109	gb->pristineRomSize = vf->size(vf);
110	vf->seek(vf, 0, SEEK_SET);
111	gb->isPristine = true;
112#ifdef _3DS
113	if (gb->pristineRomSize <= romBufferSize) {
114		gb->memory.rom = romBuffer;
115		vf->read(vf, romBuffer, gb->pristineRomSize);
116	}
117#else
118	gb->memory.rom = vf->map(vf, gb->pristineRomSize, MAP_READ);
119#endif
120	if (!gb->memory.rom) {
121		return false;
122	}
123	gb->yankedRomSize = 0;
124	gb->memory.romBase = gb->memory.rom;
125	gb->memory.romSize = gb->pristineRomSize;
126	gb->romCrc32 = doCrc32(gb->memory.rom, gb->memory.romSize);
127	GBMBCSwitchBank(gb, gb->memory.currentBank);
128
129	if (gb->cpu) {
130		struct LR35902Core* cpu = gb->cpu;
131		cpu->memory.setActiveRegion(cpu, cpu->pc);
132	}
133
134	// TODO: error check
135	return true;
136}
137
138bool GBLoadSave(struct GB* gb, struct VFile* vf) {
139	gb->sramVf = vf;
140	gb->sramRealVf = vf;
141	return vf;
142}
143
144static void GBSramDeinit(struct GB* gb) {
145	if (gb->sramVf) {
146		gb->sramVf->unmap(gb->sramVf, gb->memory.sram, gb->sramSize);
147		if (gb->memory.mbcType == GB_MBC3_RTC && gb->sramVf == gb->sramRealVf) {
148			GBMBCRTCWrite(gb);
149		}
150		gb->sramVf = NULL;
151	} else if (gb->memory.sram) {
152		mappedMemoryFree(gb->memory.sram, gb->sramSize);
153	}
154	gb->memory.sram = 0;
155}
156
157void GBResizeSram(struct GB* gb, size_t size) {
158	if (gb->memory.sram && size <= gb->sramSize) {
159		return;
160	}
161	mLOG(GB, INFO, "Resizing SRAM to %"PRIz"u bytes", size);
162	struct VFile* vf = gb->sramVf;
163	if (vf) {
164		if (vf == gb->sramRealVf) {
165			ssize_t vfSize = vf->size(vf);
166			if (vfSize >= 0 && (size_t) vfSize < size) {
167				uint8_t extdataBuffer[0x100];
168				if (vfSize & 0xFF) {
169					vf->seek(vf, -(vfSize & 0xFF), SEEK_END);
170					vf->read(vf, extdataBuffer, vfSize & 0xFF);
171				}
172				if (gb->memory.sram) {
173					vf->unmap(vf, gb->memory.sram, gb->sramSize);
174				}
175				vf->truncate(vf, size + (vfSize & 0xFF));
176				if (vfSize & 0xFF) {
177					vf->seek(vf, size, SEEK_SET);
178					vf->write(vf, extdataBuffer, vfSize & 0xFF);
179				}
180				gb->memory.sram = vf->map(vf, size, MAP_WRITE);
181				memset(&gb->memory.sram[gb->sramSize], 0xFF, size - gb->sramSize);
182			} else if (size > gb->sramSize || !gb->memory.sram) {
183				if (gb->memory.sram) {
184					vf->unmap(vf, gb->memory.sram, gb->sramSize);
185				}
186				gb->memory.sram = vf->map(vf, size, MAP_WRITE);
187			}
188		} else {
189			if (gb->memory.sram) {
190				vf->unmap(vf, gb->memory.sram, gb->sramSize);
191			}
192			gb->memory.sram = vf->map(vf, size, MAP_READ);
193		}
194		if (gb->memory.sram == (void*) -1) {
195			gb->memory.sram = NULL;
196		}
197	} else {
198		uint8_t* newSram = anonymousMemoryMap(size);
199		if (gb->memory.sram) {
200			if (size > gb->sramSize) {
201				memcpy(newSram, gb->memory.sram, gb->sramSize);
202				memset(&newSram[gb->sramSize], 0xFF, size - gb->sramSize);
203			} else {
204				memcpy(newSram, gb->memory.sram, size);
205			}
206			mappedMemoryFree(gb->memory.sram, gb->sramSize);
207		} else {
208			memset(newSram, 0xFF, size);
209		}
210		gb->memory.sram = newSram;
211	}
212	if (gb->sramSize < size) {
213		gb->sramSize = size;
214	}
215}
216
217void GBSramClean(struct GB* gb, uint32_t frameCount) {
218	// TODO: Share with GBASavedataClean
219	if (!gb->sramVf || gb->sramVf != gb->sramRealVf) {
220		return;
221	}
222	if (gb->sramDirty & GB_SRAM_DIRT_NEW) {
223		gb->sramDirtAge = frameCount;
224		gb->sramDirty &= ~GB_SRAM_DIRT_NEW;
225		if (!(gb->sramDirty & GB_SRAM_DIRT_SEEN)) {
226			gb->sramDirty |= GB_SRAM_DIRT_SEEN;
227		}
228	} else if ((gb->sramDirty & GB_SRAM_DIRT_SEEN) && frameCount - gb->sramDirtAge > CLEANUP_THRESHOLD) {
229		if (gb->memory.mbcType == GB_MBC3_RTC) {
230			GBMBCRTCWrite(gb);
231		}
232		gb->sramDirty = 0;
233		if (gb->memory.sram && gb->sramVf->sync(gb->sramVf, gb->memory.sram, gb->sramSize)) {
234			mLOG(GB_MEM, INFO, "Savedata synced");
235		} else {
236			mLOG(GB_MEM, INFO, "Savedata failed to sync!");
237		}
238	}
239}
240
241void GBSavedataMask(struct GB* gb, struct VFile* vf, bool writeback) {
242	GBSramDeinit(gb);
243	gb->sramVf = vf;
244	gb->sramMaskWriteback = writeback;
245	gb->memory.sram = vf->map(vf, gb->sramSize, MAP_READ);
246	GBMBCSwitchSramBank(gb, gb->memory.sramCurrentBank);
247}
248
249void GBSavedataUnmask(struct GB* gb) {
250	if (gb->sramVf == gb->sramRealVf) {
251		return;
252	}
253	struct VFile* vf = gb->sramVf;
254	GBSramDeinit(gb);
255	gb->sramVf = gb->sramRealVf;
256	gb->memory.sram = gb->sramVf->map(gb->sramVf, gb->sramSize, MAP_WRITE);
257	if (gb->sramMaskWriteback) {
258		vf->read(vf, gb->memory.sram, gb->sramSize);
259	}
260	vf->close(vf);
261}
262
263void GBUnloadROM(struct GB* gb) {
264	// TODO: Share with GBAUnloadROM
265	if (gb->memory.rom && gb->memory.romBase != gb->memory.rom && !gb->isPristine) {
266		free(gb->memory.romBase);
267	}
268	if (gb->memory.rom && !gb->isPristine) {
269		if (gb->yankedRomSize) {
270			gb->yankedRomSize = 0;
271		}
272		mappedMemoryFree(gb->memory.rom, GB_SIZE_CART_MAX);
273	}
274
275	if (gb->romVf) {
276#ifndef _3DS
277		gb->romVf->unmap(gb->romVf, gb->memory.rom, gb->pristineRomSize);
278#endif
279		gb->romVf->close(gb->romVf);
280		gb->romVf = NULL;
281	}
282	gb->memory.rom = NULL;
283	gb->isPristine = false;
284
285	GBSavedataUnmask(gb);
286	GBSramDeinit(gb);
287	if (gb->sramRealVf) {
288		gb->sramRealVf->close(gb->sramRealVf);
289	}
290	gb->sramRealVf = NULL;
291	gb->sramVf = NULL;
292}
293
294void GBSynthesizeROM(struct VFile* vf) {
295	if (!vf) {
296		return;
297	}
298	const struct GBCartridge cart = {
299		.logo = { _knownHeader[0], _knownHeader[1], _knownHeader[2], _knownHeader[3]}
300	};
301
302	vf->seek(vf, 0x100, SEEK_SET);
303	vf->write(vf, &cart, sizeof(cart));
304}
305
306void GBLoadBIOS(struct GB* gb, struct VFile* vf) {
307	gb->biosVf = vf;
308}
309
310void GBApplyPatch(struct GB* gb, struct Patch* patch) {
311	size_t patchedSize = patch->outputSize(patch, gb->memory.romSize);
312	if (!patchedSize) {
313		return;
314	}
315	if (patchedSize > GB_SIZE_CART_MAX) {
316		patchedSize = GB_SIZE_CART_MAX;
317	}
318	void* newRom = anonymousMemoryMap(GB_SIZE_CART_MAX);
319	if (!patch->applyPatch(patch, gb->memory.rom, gb->pristineRomSize, newRom, patchedSize)) {
320		mappedMemoryFree(newRom, GB_SIZE_CART_MAX);
321		return;
322	}
323	if (gb->romVf) {
324#ifndef _3DS
325		gb->romVf->unmap(gb->romVf, gb->memory.rom, gb->pristineRomSize);
326#endif
327		gb->romVf->close(gb->romVf);
328		gb->romVf = NULL;
329	}
330	gb->isPristine = false;
331	if (gb->memory.romBase == gb->memory.rom) {
332		gb->memory.romBase = newRom;
333	}
334	gb->memory.rom = newRom;
335	gb->memory.romSize = patchedSize;
336	gb->romCrc32 = doCrc32(gb->memory.rom, gb->memory.romSize);
337	gb->cpu->memory.setActiveRegion(gb->cpu, gb->cpu->pc);
338}
339
340void GBDestroy(struct GB* gb) {
341	GBUnloadROM(gb);
342
343	if (gb->biosVf) {
344		gb->biosVf->close(gb->biosVf);
345		gb->biosVf = 0;
346	}
347
348	GBMemoryDeinit(gb);
349	GBAudioDeinit(&gb->audio);
350	GBVideoDeinit(&gb->video);
351	GBSIODeinit(&gb->sio);
352	mCoreCallbacksListDeinit(&gb->coreCallbacks);
353}
354
355void GBInterruptHandlerInit(struct LR35902InterruptHandler* irqh) {
356	irqh->reset = GBReset;
357	irqh->processEvents = GBProcessEvents;
358	irqh->setInterrupts = GBSetInterrupts;
359	irqh->hitIllegal = GBIllegal;
360	irqh->stop = GBStop;
361	irqh->halt = GBHalt;
362}
363
364static uint32_t _GBBiosCRC32(struct VFile* vf) {
365	ssize_t size = vf->size(vf);
366	if (size <= 0 || size > GB_SIZE_CART_BANK0) {
367		return 0;
368	}
369	void* bios = vf->map(vf, size, MAP_READ);
370	uint32_t biosCrc = doCrc32(bios, size);
371	vf->unmap(vf, bios, size);
372	return biosCrc;
373}
374
375bool GBIsBIOS(struct VFile* vf) {
376	switch (_GBBiosCRC32(vf)) {
377	case DMG_BIOS_CHECKSUM:
378	case DMG_2_BIOS_CHECKSUM:
379	case CGB_BIOS_CHECKSUM:
380		return true;
381	default:
382		return false;
383	}
384}
385
386void GBReset(struct LR35902Core* cpu) {
387	struct GB* gb = (struct GB*) cpu->master;
388	GBDetectModel(gb);
389	if (gb->biosVf) {
390		if (!GBIsBIOS(gb->biosVf)) {
391			gb->biosVf->close(gb->biosVf);
392			gb->biosVf = NULL;
393		} else {
394			gb->biosVf->seek(gb->biosVf, 0, SEEK_SET);
395			gb->memory.romBase = malloc(GB_SIZE_CART_BANK0);
396			ssize_t size = gb->biosVf->read(gb->biosVf, gb->memory.romBase, GB_SIZE_CART_BANK0);
397			memcpy(&gb->memory.romBase[size], &gb->memory.rom[size], GB_SIZE_CART_BANK0 - size);
398			if (size > 0x100) {
399				memcpy(&gb->memory.romBase[0x100], &gb->memory.rom[0x100], sizeof(struct GBCartridge));
400			}
401
402			cpu->a = 0;
403			cpu->f.packed = 0;
404			cpu->c = 0;
405			cpu->e = 0;
406			cpu->h = 0;
407			cpu->l = 0;
408			cpu->sp = 0;
409			cpu->pc = 0;
410		}
411	}
412
413	cpu->b = 0;
414	cpu->d = 0;
415
416	if (!gb->biosVf) {
417		switch (gb->model) {
418		case GB_MODEL_DMG:
419			// TODO: SGB
420		case GB_MODEL_SGB:
421		case GB_MODEL_AUTODETECT: // Silence warnings
422			gb->model = GB_MODEL_DMG;
423			cpu->a = 1;
424			cpu->f.packed = 0xB0;
425			cpu->c = 0x13;
426			cpu->e = 0xD8;
427			cpu->h = 1;
428			cpu->l = 0x4D;
429			break;
430		case GB_MODEL_AGB:
431			cpu->b = 1;
432			// Fall through
433		case GB_MODEL_CGB:
434			cpu->a = 0x11;
435			cpu->f.packed = 0x80;
436			cpu->c = 0;
437			cpu->e = 0x08;
438			cpu->h = 0;
439			cpu->l = 0x7C;
440			break;
441		}
442
443		cpu->sp = 0xFFFE;
444		cpu->pc = 0x100;
445	}
446
447	gb->cpuBlocked = false;
448	gb->earlyExit = false;
449	gb->doubleSpeed = 0;
450
451	cpu->memory.setActiveRegion(cpu, cpu->pc);
452
453	if (gb->yankedRomSize) {
454		gb->memory.romSize = gb->yankedRomSize;
455		gb->yankedRomSize = 0;
456	}
457
458	mTimingClear(&gb->timing);
459
460	GBMemoryReset(gb);
461	GBVideoReset(&gb->video);
462	GBTimerReset(&gb->timer);
463	mTimingSchedule(&gb->timing, &gb->timer.event, GB_DMG_DIV_PERIOD);
464
465	GBAudioReset(&gb->audio);
466	GBIOReset(gb);
467	GBSIOReset(&gb->sio);
468
469	GBSavedataUnmask(gb);
470}
471
472void GBDetectModel(struct GB* gb) {
473	if (gb->model != GB_MODEL_AUTODETECT) {
474		return;
475	}
476	if (gb->biosVf) {
477		switch (_GBBiosCRC32(gb->biosVf)) {
478		case DMG_BIOS_CHECKSUM:
479		case DMG_2_BIOS_CHECKSUM:
480			gb->model = GB_MODEL_DMG;
481			break;
482		case CGB_BIOS_CHECKSUM:
483			gb->model = GB_MODEL_CGB;
484			break;
485		default:
486			gb->biosVf->close(gb->biosVf);
487			gb->biosVf = NULL;
488		}
489	}
490	if (gb->model == GB_MODEL_AUTODETECT && gb->memory.rom) {
491		const struct GBCartridge* cart = (const struct GBCartridge*) &gb->memory.rom[0x100];
492		if (cart->cgb & 0x80) {
493			gb->model = GB_MODEL_CGB;
494		} else {
495			gb->model = GB_MODEL_DMG;
496		}
497	}
498
499	switch (gb->model) {
500	case GB_MODEL_DMG:
501	case GB_MODEL_SGB:
502	case GB_MODEL_AUTODETECT: //Silence warnings
503		gb->audio.style = GB_AUDIO_DMG;
504		break;
505	case GB_MODEL_AGB:
506	case GB_MODEL_CGB:
507		gb->audio.style = GB_AUDIO_CGB;
508		break;
509	}
510}
511
512void GBUpdateIRQs(struct GB* gb) {
513	int irqs = gb->memory.ie & gb->memory.io[REG_IF];
514	if (!irqs) {
515		return;
516	}
517	gb->cpu->halted = false;
518
519	if (!gb->memory.ime || gb->cpu->irqPending) {
520		return;
521	}
522
523	if (irqs & (1 << GB_IRQ_VBLANK)) {
524		LR35902RaiseIRQ(gb->cpu, GB_VECTOR_VBLANK);
525		gb->memory.io[REG_IF] &= ~(1 << GB_IRQ_VBLANK);
526		return;
527	}
528	if (irqs & (1 << GB_IRQ_LCDSTAT)) {
529		LR35902RaiseIRQ(gb->cpu, GB_VECTOR_LCDSTAT);
530		gb->memory.io[REG_IF] &= ~(1 << GB_IRQ_LCDSTAT);
531		return;
532	}
533	if (irqs & (1 << GB_IRQ_TIMER)) {
534		LR35902RaiseIRQ(gb->cpu, GB_VECTOR_TIMER);
535		gb->memory.io[REG_IF] &= ~(1 << GB_IRQ_TIMER);
536		return;
537	}
538	if (irqs & (1 << GB_IRQ_SIO)) {
539		LR35902RaiseIRQ(gb->cpu, GB_VECTOR_SIO);
540		gb->memory.io[REG_IF] &= ~(1 << GB_IRQ_SIO);
541		return;
542	}
543	if (irqs & (1 << GB_IRQ_KEYPAD)) {
544		LR35902RaiseIRQ(gb->cpu, GB_VECTOR_KEYPAD);
545		gb->memory.io[REG_IF] &= ~(1 << GB_IRQ_KEYPAD);
546	}
547}
548
549void GBProcessEvents(struct LR35902Core* cpu) {
550	struct GB* gb = (struct GB*) cpu->master;
551	do {
552		int32_t cycles = cpu->cycles;
553		int32_t nextEvent;
554
555		cpu->cycles = 0;
556		cpu->nextEvent = INT_MAX;
557
558		nextEvent = cycles;
559		do {
560			nextEvent = mTimingTick(&gb->timing, nextEvent);
561		} while (gb->cpuBlocked);
562		cpu->nextEvent = nextEvent;
563
564		if (gb->earlyExit) {
565			gb->earlyExit = false;
566			break;
567		}
568		if (cpu->halted) {
569			cpu->cycles = cpu->nextEvent;
570			if (!gb->memory.ie || !gb->memory.ime) {
571				break;
572			}
573		}
574	} while (cpu->cycles >= cpu->nextEvent);
575}
576
577void GBSetInterrupts(struct LR35902Core* cpu, bool enable) {
578	struct GB* gb = (struct GB*) cpu->master;
579	if (!enable) {
580		gb->memory.ime = enable;
581		mTimingDeschedule(&gb->timing, &gb->eiPending);
582		GBUpdateIRQs(gb);
583	} else {
584		mTimingDeschedule(&gb->timing, &gb->eiPending);
585		mTimingSchedule(&gb->timing, &gb->eiPending, 4);
586	}
587}
588
589static void _enableInterrupts(struct mTiming* timing, void* user, uint32_t cyclesLate) {
590	UNUSED(timing);
591	UNUSED(cyclesLate);
592	struct GB* gb = user;
593	gb->memory.ime = true;
594	GBUpdateIRQs(gb);
595}
596
597void GBHalt(struct LR35902Core* cpu) {
598	if (!cpu->irqPending) {
599		cpu->cycles = cpu->nextEvent;
600		cpu->halted = true;
601	}
602}
603
604void GBStop(struct LR35902Core* cpu) {
605	struct GB* gb = (struct GB*) cpu->master;
606	if (cpu->bus) {
607		mLOG(GB, GAME_ERROR, "Hit illegal stop at address %04X:%02X\n", cpu->pc, cpu->bus);
608	}
609	if (gb->memory.io[REG_KEY1] & 1) {
610		gb->doubleSpeed ^= 1;
611		gb->audio.timingFactor = gb->doubleSpeed + 1;
612		gb->memory.io[REG_KEY1] = 0;
613		gb->memory.io[REG_KEY1] |= gb->doubleSpeed << 7;
614	} else if (cpu->bus) {
615#ifdef USE_DEBUGGERS
616		if (cpu->components && cpu->components[CPU_COMPONENT_DEBUGGER]) {
617			struct mDebuggerEntryInfo info = {
618				.address = cpu->pc - 1,
619				.opcode = 0x1000 | cpu->bus
620			};
621			mDebuggerEnter((struct mDebugger*) cpu->components[CPU_COMPONENT_DEBUGGER], DEBUGGER_ENTER_ILLEGAL_OP, &info);
622		}
623#endif
624		// Hang forever
625		gb->memory.ime = 0;
626		cpu->pc -= 2;
627	}
628	// TODO: Actually stop
629}
630
631void GBIllegal(struct LR35902Core* cpu) {
632	struct GB* gb = (struct GB*) cpu->master;
633	mLOG(GB, GAME_ERROR, "Hit illegal opcode at address %04X:%02X\n", cpu->pc, cpu->bus);
634#ifdef USE_DEBUGGERS
635	if (cpu->components && cpu->components[CPU_COMPONENT_DEBUGGER]) {
636		struct mDebuggerEntryInfo info = {
637			.address = cpu->pc,
638			.opcode = cpu->bus
639		};
640		mDebuggerEnter((struct mDebugger*) cpu->components[CPU_COMPONENT_DEBUGGER], DEBUGGER_ENTER_ILLEGAL_OP, &info);
641	}
642#endif
643	// Hang forever
644	gb->memory.ime = 0;
645	--cpu->pc;
646}
647
648bool GBIsROM(struct VFile* vf) {
649	vf->seek(vf, 0x104, SEEK_SET);
650	uint8_t header[4];
651
652	if (vf->read(vf, &header, sizeof(header)) < (ssize_t) sizeof(header)) {
653		return false;
654	}
655	if (memcmp(header, _knownHeader, sizeof(header))) {
656		return false;
657	}
658	return true;
659}
660
661void GBGetGameTitle(const struct GB* gb, char* out) {
662	const struct GBCartridge* cart = NULL;
663	if (gb->memory.rom) {
664		cart = (const struct GBCartridge*) &gb->memory.rom[0x100];
665	}
666	if (!cart) {
667		return;
668	}
669	if (cart->oldLicensee != 0x33) {
670		memcpy(out, cart->titleLong, 16);
671	} else {
672		memcpy(out, cart->titleShort, 11);
673	}
674}
675
676void GBGetGameCode(const struct GB* gb, char* out) {
677	memset(out, 0, 8);
678	const struct GBCartridge* cart = NULL;
679	if (gb->memory.rom) {
680		cart = (const struct GBCartridge*) &gb->memory.rom[0x100];
681	}
682	if (!cart) {
683		return;
684	}
685	if (cart->cgb == 0xC0) {
686		memcpy(out, "CGB-????", 8);
687	} else {
688		memcpy(out, "DMG-????", 8);
689	}
690	if (cart->oldLicensee == 0x33) {
691		memcpy(&out[4], cart->maker, 4);
692	}
693}
694
695void GBFrameEnded(struct GB* gb) {
696	GBSramClean(gb, gb->video.frameCounter);
697
698	if (gb->cpu->components && gb->cpu->components[CPU_COMPONENT_CHEAT_DEVICE]) {
699		struct mCheatDevice* device = (struct mCheatDevice*) gb->cpu->components[CPU_COMPONENT_CHEAT_DEVICE];
700		size_t i;
701		for (i = 0; i < mCheatSetsSize(&device->cheats); ++i) {
702			struct mCheatSet* cheats = *mCheatSetsGetPointer(&device->cheats, i);
703			mCheatRefresh(device, cheats);
704		}
705	}
706}