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