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mGBA Game Boy Advance Emulator

src/gba/gba.c (view raw)

  1/* Copyright (c) 2013-2015 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/gba/gba.h>
  7
  8#include <mgba/internal/arm/isa-inlines.h>
  9#include <mgba/internal/arm/debugger/debugger.h>
 10#include <mgba/internal/arm/decoder.h>
 11
 12#include <mgba/internal/gba/bios.h>
 13#include <mgba/internal/gba/cheats.h>
 14#include <mgba/internal/gba/io.h>
 15#include <mgba/internal/gba/overrides.h>
 16
 17#include <mgba-util/patch.h>
 18#include <mgba-util/crc32.h>
 19#include <mgba-util/math.h>
 20#include <mgba-util/memory.h>
 21#include <mgba-util/vfs.h>
 22
 23#ifdef USE_ELF
 24#include <mgba-util/elf-read.h>
 25#endif
 26
 27#define GBA_IRQ_DELAY 7
 28
 29mLOG_DEFINE_CATEGORY(GBA, "GBA", "gba");
 30mLOG_DEFINE_CATEGORY(GBA_DEBUG, "GBA Debug", "gba.debug");
 31
 32const uint32_t GBA_COMPONENT_MAGIC = 0x1000000;
 33
 34static const size_t GBA_ROM_MAGIC_OFFSET = 3;
 35static const uint8_t GBA_ROM_MAGIC[] = { 0xEA };
 36
 37static const size_t GBA_ROM_MAGIC_OFFSET2 = 0xB2;
 38static const uint8_t GBA_ROM_MAGIC2[] = { 0x96 };
 39
 40static const size_t GBA_MB_MAGIC_OFFSET = 0xC0;
 41
 42static void GBAInit(void* cpu, struct mCPUComponent* component);
 43static void GBAInterruptHandlerInit(struct ARMInterruptHandler* irqh);
 44static void GBAProcessEvents(struct ARMCore* cpu);
 45static void GBAHitStub(struct ARMCore* cpu, uint32_t opcode);
 46static void GBAIllegal(struct ARMCore* cpu, uint32_t opcode);
 47static void GBABreakpoint(struct ARMCore* cpu, int immediate);
 48static void GBATestIRQNoDelay(struct ARMCore* cpu);
 49
 50static void _triggerIRQ(struct mTiming*, void* user, uint32_t cyclesLate);
 51
 52#ifdef USE_DEBUGGERS
 53static bool _setSoftwareBreakpoint(struct ARMDebugger*, uint32_t address, enum ExecutionMode mode, uint32_t* opcode);
 54static void _clearSoftwareBreakpoint(struct ARMDebugger*, const struct ARMDebugBreakpoint*);
 55#endif
 56
 57#ifdef FIXED_ROM_BUFFER
 58extern uint32_t* romBuffer;
 59extern size_t romBufferSize;
 60#endif
 61
 62void GBACreate(struct GBA* gba) {
 63	gba->d.id = GBA_COMPONENT_MAGIC;
 64	gba->d.init = GBAInit;
 65	gba->d.deinit = 0;
 66}
 67
 68static void GBAInit(void* cpu, struct mCPUComponent* component) {
 69	struct GBA* gba = (struct GBA*) component;
 70	gba->cpu = cpu;
 71	gba->debugger = 0;
 72	gba->sync = 0;
 73
 74	GBAInterruptHandlerInit(&gba->cpu->irqh);
 75	GBAMemoryInit(gba);
 76
 77	gba->memory.savedata.timing = &gba->timing;
 78	GBASavedataInit(&gba->memory.savedata, NULL);
 79
 80	gba->video.p = gba;
 81	GBAVideoInit(&gba->video);
 82
 83	gba->audio.p = gba;
 84	GBAAudioInit(&gba->audio, GBA_AUDIO_SAMPLES);
 85
 86	GBAIOInit(gba);
 87
 88	gba->sio.p = gba;
 89	GBASIOInit(&gba->sio);
 90
 91	GBAHardwareInit(&gba->memory.hw, NULL);
 92
 93	gba->keySource = 0;
 94	gba->rotationSource = 0;
 95	gba->luminanceSource = 0;
 96	gba->rtcSource = 0;
 97	gba->rumble = 0;
 98
 99	gba->romVf = 0;
100	gba->biosVf = 0;
101
102	gba->stream = NULL;
103	gba->keyCallback = NULL;
104	mCoreCallbacksListInit(&gba->coreCallbacks, 0);
105
106	gba->biosChecksum = GBAChecksum(gba->memory.bios, SIZE_BIOS);
107
108	gba->idleOptimization = IDLE_LOOP_REMOVE;
109	gba->idleLoop = IDLE_LOOP_NONE;
110
111	gba->hardCrash = true;
112	gba->allowOpposingDirections = true;
113
114	gba->performingDMA = false;
115
116	gba->isPristine = false;
117	gba->pristineRomSize = 0;
118	gba->yankedRomSize = 0;
119
120	mTimingInit(&gba->timing, &gba->cpu->cycles, &gba->cpu->nextEvent);
121
122	gba->irqEvent.name = "GBA IRQ Event";
123	gba->irqEvent.callback = _triggerIRQ;
124	gba->irqEvent.context = gba;
125	gba->irqEvent.priority = 0;
126}
127
128void GBAUnloadROM(struct GBA* gba) {
129	if (gba->memory.rom && !gba->isPristine) {
130		if (gba->yankedRomSize) {
131			gba->yankedRomSize = 0;
132		}
133		mappedMemoryFree(gba->memory.rom, SIZE_CART0);
134	}
135
136	if (gba->romVf) {
137#ifndef FIXED_ROM_BUFFER
138		if (gba->isPristine) {
139			gba->romVf->unmap(gba->romVf, gba->memory.rom, gba->pristineRomSize);
140		}
141#endif
142		gba->romVf->close(gba->romVf);
143		gba->romVf = NULL;
144	}
145	gba->memory.rom = NULL;
146	gba->isPristine = false;
147
148	gba->memory.savedata.maskWriteback = false;
149	GBASavedataUnmask(&gba->memory.savedata);
150	GBASavedataDeinit(&gba->memory.savedata);
151	if (gba->memory.savedata.realVf) {
152		gba->memory.savedata.realVf->close(gba->memory.savedata.realVf);
153		gba->memory.savedata.realVf = 0;
154	}
155	gba->idleLoop = IDLE_LOOP_NONE;
156}
157
158void GBADestroy(struct GBA* gba) {
159	GBAUnloadROM(gba);
160
161	if (gba->biosVf) {
162		gba->biosVf->unmap(gba->biosVf, gba->memory.bios, SIZE_BIOS);
163		gba->biosVf->close(gba->biosVf);
164		gba->biosVf = 0;
165	}
166
167	GBAMemoryDeinit(gba);
168	GBAVideoDeinit(&gba->video);
169	GBAAudioDeinit(&gba->audio);
170	GBASIODeinit(&gba->sio);
171	mTimingDeinit(&gba->timing);
172	mCoreCallbacksListDeinit(&gba->coreCallbacks);
173}
174
175void GBAInterruptHandlerInit(struct ARMInterruptHandler* irqh) {
176	irqh->reset = GBAReset;
177	irqh->processEvents = GBAProcessEvents;
178	irqh->swi16 = GBASwi16;
179	irqh->swi32 = GBASwi32;
180	irqh->hitIllegal = GBAIllegal;
181	irqh->readCPSR = GBATestIRQNoDelay;
182	irqh->hitStub = GBAHitStub;
183	irqh->bkpt16 = GBABreakpoint;
184	irqh->bkpt32 = GBABreakpoint;
185}
186
187void GBAReset(struct ARMCore* cpu) {
188	ARMSetPrivilegeMode(cpu, MODE_IRQ);
189	cpu->gprs[ARM_SP] = SP_BASE_IRQ;
190	ARMSetPrivilegeMode(cpu, MODE_SUPERVISOR);
191	cpu->gprs[ARM_SP] = SP_BASE_SUPERVISOR;
192	ARMSetPrivilegeMode(cpu, MODE_SYSTEM);
193	cpu->gprs[ARM_SP] = SP_BASE_SYSTEM;
194
195	struct GBA* gba = (struct GBA*) cpu->master;
196	gba->memory.savedata.maskWriteback = false;
197	GBASavedataUnmask(&gba->memory.savedata);
198
199	gba->cpuBlocked = false;
200	gba->earlyExit = false;
201	gba->dmaPC = 0;
202	if (gba->yankedRomSize) {
203		gba->memory.romSize = gba->yankedRomSize;
204		gba->memory.romMask = toPow2(gba->memory.romSize) - 1;
205		gba->yankedRomSize = 0;
206	}
207	mTimingClear(&gba->timing);
208	GBAMemoryReset(gba);
209	GBAVideoReset(&gba->video);
210	GBAAudioReset(&gba->audio);
211	GBAIOInit(gba);
212	GBATimerInit(gba);
213
214	GBASIOReset(&gba->sio);
215
216	bool isELF = false;
217#ifdef USE_ELF
218	struct ELF* elf = ELFOpen(gba->romVf);
219	if (elf) {
220		isELF = true;
221		ELFClose(elf);
222	}
223#endif
224
225	if (GBAIsMB(gba->romVf) && !isELF) {
226		gba->romVf->seek(gba->romVf, 0, SEEK_SET);
227		gba->romVf->read(gba->romVf, gba->memory.wram, gba->pristineRomSize);
228	}
229
230	gba->lastJump = 0;
231	gba->haltPending = false;
232	gba->idleDetectionStep = 0;
233	gba->idleDetectionFailures = 0;
234
235	gba->debug = false;
236	memset(gba->debugString, 0, sizeof(gba->debugString));
237
238
239	if (gba->romVf && gba->pristineRomSize > SIZE_CART0) {
240		char ident;
241		gba->romVf->seek(gba->romVf, 0xAC, SEEK_SET);
242		gba->romVf->read(gba->romVf, &ident, 1);
243		gba->romVf->seek(gba->romVf, 0, SEEK_SET);
244		if (ident == 'M') {
245			GBAMatrixReset(gba);
246		}
247	}
248}
249
250void GBASkipBIOS(struct GBA* gba) {
251	struct ARMCore* cpu = gba->cpu;
252	if (cpu->gprs[ARM_PC] == BASE_RESET + WORD_SIZE_ARM) {
253		if (gba->memory.rom) {
254			cpu->gprs[ARM_PC] = BASE_CART0;
255		} else {
256			cpu->gprs[ARM_PC] = BASE_WORKING_RAM + 0xC0;
257		}
258		gba->video.vcount = 0x7D;
259		gba->memory.io[REG_VCOUNT >> 1] = 0x7D;
260		gba->memory.io[REG_POSTFLG >> 1] = 1;
261		ARMWritePC(cpu);
262	}
263}
264
265static void GBAProcessEvents(struct ARMCore* cpu) {
266	struct GBA* gba = (struct GBA*) cpu->master;
267
268	gba->bus = cpu->prefetch[1];
269	if (cpu->executionMode == MODE_THUMB) {
270		gba->bus |= cpu->prefetch[1] << 16;
271	}
272
273	int32_t nextEvent = cpu->nextEvent;
274	while (cpu->cycles >= nextEvent) {
275		cpu->nextEvent = INT_MAX;
276		nextEvent = 0;
277		do {
278			int32_t cycles = cpu->cycles;
279			cpu->cycles = 0;
280#ifdef USE_DEBUGGERS
281			gba->timing.globalCycles += cycles;
282#endif
283#ifndef NDEBUG
284			if (cycles < 0) {
285				mLOG(GBA, FATAL, "Negative cycles passed: %i", cycles);
286			}
287#endif
288			nextEvent = mTimingTick(&gba->timing, cycles < nextEvent ? nextEvent : cycles);
289		} while (gba->cpuBlocked && !gba->earlyExit);
290
291		cpu->nextEvent = nextEvent;
292		if (cpu->halted) {
293			cpu->cycles = nextEvent;
294			if (!gba->memory.io[REG_IME >> 1] || !gba->memory.io[REG_IE >> 1]) {
295				break;
296			}
297		}
298#ifndef NDEBUG
299		else if (nextEvent < 0) {
300			mLOG(GBA, FATAL, "Negative cycles will pass: %i", nextEvent);
301		}
302#endif
303		if (gba->earlyExit) {
304			break;
305		}
306	}
307	gba->earlyExit = false;
308	if (gba->cpuBlocked) {
309		cpu->cycles = cpu->nextEvent;
310	}
311}
312
313#ifdef USE_DEBUGGERS
314void GBAAttachDebugger(struct GBA* gba, struct mDebugger* debugger) {
315	gba->debugger = (struct ARMDebugger*) debugger->platform;
316	gba->debugger->setSoftwareBreakpoint = _setSoftwareBreakpoint;
317	gba->debugger->clearSoftwareBreakpoint = _clearSoftwareBreakpoint;
318	gba->cpu->components[CPU_COMPONENT_DEBUGGER] = &debugger->d;
319	ARMHotplugAttach(gba->cpu, CPU_COMPONENT_DEBUGGER);
320}
321
322void GBADetachDebugger(struct GBA* gba) {
323	if (gba->debugger) {
324		ARMHotplugDetach(gba->cpu, CPU_COMPONENT_DEBUGGER);
325	}
326	gba->cpu->components[CPU_COMPONENT_DEBUGGER] = NULL;
327	gba->debugger = NULL;
328}
329#endif
330
331bool GBALoadNull(struct GBA* gba) {
332	GBAUnloadROM(gba);
333	gba->romVf = NULL;
334	gba->pristineRomSize = 0;
335#ifndef FIXED_ROM_BUFFER
336	gba->memory.rom = anonymousMemoryMap(SIZE_CART0);
337#else
338	gba->memory.rom = romBuffer;
339#endif
340	gba->isPristine = false;
341	gba->yankedRomSize = 0;
342	gba->memory.romSize = SIZE_CART0;
343	gba->memory.romMask = SIZE_CART0 - 1;
344	gba->memory.mirroring = false;
345	gba->romCrc32 = 0;
346
347	if (gba->cpu) {
348		gba->cpu->memory.setActiveRegion(gba->cpu, gba->cpu->gprs[ARM_PC]);
349	}
350	GBAHardwareInit(&gba->memory.hw, &((uint16_t*) gba->memory.rom)[GPIO_REG_DATA >> 1]);
351	return true;
352}
353
354bool GBALoadMB(struct GBA* gba, struct VFile* vf) {
355	GBAUnloadROM(gba);
356	gba->romVf = vf;
357	gba->pristineRomSize = vf->size(vf);
358	vf->seek(vf, 0, SEEK_SET);
359	if (gba->pristineRomSize > SIZE_WORKING_RAM) {
360		gba->pristineRomSize = SIZE_WORKING_RAM;
361	}
362	gba->isPristine = true;
363	memset(gba->memory.wram, 0, SIZE_WORKING_RAM);
364	gba->yankedRomSize = 0;
365	gba->memory.romSize = 0;
366	gba->memory.romMask = 0;
367	gba->romCrc32 = doCrc32(gba->memory.wram, gba->pristineRomSize);
368	if (gba->cpu && gba->memory.activeRegion == REGION_WORKING_RAM) {
369		gba->cpu->memory.setActiveRegion(gba->cpu, gba->cpu->gprs[ARM_PC]);
370	}
371	return true;
372}
373
374bool GBALoadROM(struct GBA* gba, struct VFile* vf) {
375	if (!vf) {
376		return false;
377	}
378	GBAUnloadROM(gba);
379	gba->romVf = vf;
380	gba->pristineRomSize = vf->size(vf);
381	vf->seek(vf, 0, SEEK_SET);
382	if (gba->pristineRomSize > SIZE_CART0) {
383		gba->isPristine = false;
384		char ident;
385		vf->seek(vf, 0xAC, SEEK_SET);
386		vf->read(vf, &ident, 1);
387		if (ident == 'M') {
388			gba->memory.romSize = 0x01000000;
389#ifdef FIXED_ROM_BUFFER
390			gba->memory.rom = romBuffer;
391#else
392			gba->memory.rom = anonymousMemoryMap(SIZE_CART0);
393#endif
394		} else {
395			gba->memory.rom = vf->map(vf, SIZE_CART0, MAP_READ);
396			gba->memory.romSize = SIZE_CART0;
397		}
398	} else {
399		gba->isPristine = true;
400		gba->memory.rom = vf->map(vf, gba->pristineRomSize, MAP_READ);
401		gba->memory.romSize = gba->pristineRomSize;
402	}
403	if (!gba->memory.rom) {
404		mLOG(GBA, WARN, "Couldn't map ROM");
405		return false;
406	}
407	gba->yankedRomSize = 0;
408	gba->memory.romMask = toPow2(gba->memory.romSize) - 1;
409	gba->memory.mirroring = false;
410	gba->romCrc32 = doCrc32(gba->memory.rom, gba->memory.romSize);
411	if (popcount32(gba->memory.romSize) != 1) {
412		// This ROM is either a bad dump or homebrew. Emulate flash cart behavior.
413#ifndef FIXED_ROM_BUFFER
414		void* newRom = anonymousMemoryMap(SIZE_CART0);
415		memcpy(newRom, gba->memory.rom, gba->pristineRomSize);
416		gba->memory.rom = newRom;
417#endif
418		gba->memory.romSize = SIZE_CART0;
419		gba->memory.romMask = SIZE_CART0 - 1;
420		gba->isPristine = false;
421	}
422	if (gba->cpu && gba->memory.activeRegion >= REGION_CART0) {
423		gba->cpu->memory.setActiveRegion(gba->cpu, gba->cpu->gprs[ARM_PC]);
424	}
425	GBAHardwareInit(&gba->memory.hw, &((uint16_t*) gba->memory.rom)[GPIO_REG_DATA >> 1]);
426	GBAVFameDetect(&gba->memory.vfame, gba->memory.rom, gba->memory.romSize);
427	// TODO: error check
428	return true;
429}
430
431bool GBALoadSave(struct GBA* gba, struct VFile* sav) {
432	GBASavedataInit(&gba->memory.savedata, sav);
433	return sav;
434}
435
436void GBAYankROM(struct GBA* gba) {
437	gba->yankedRomSize = gba->memory.romSize;
438	gba->memory.romSize = 0;
439	gba->memory.romMask = 0;
440	GBARaiseIRQ(gba, IRQ_GAMEPAK, 0);
441}
442
443void GBALoadBIOS(struct GBA* gba, struct VFile* vf) {
444	if (vf->size(vf) != SIZE_BIOS) {
445		mLOG(GBA, WARN, "Incorrect BIOS size");
446		return;
447	}
448	uint32_t* bios = vf->map(vf, SIZE_BIOS, MAP_READ);
449	if (!bios) {
450		mLOG(GBA, WARN, "Couldn't map BIOS");
451		return;
452	}
453	if (gba->biosVf) {
454		gba->biosVf->unmap(gba->biosVf, gba->memory.bios, SIZE_BIOS);
455		gba->biosVf->close(gba->biosVf);
456	}
457	gba->biosVf = vf;
458	gba->memory.bios = bios;
459	gba->memory.fullBios = 1;
460	uint32_t checksum = GBAChecksum(gba->memory.bios, SIZE_BIOS);
461	mLOG(GBA, DEBUG, "BIOS Checksum: 0x%X", checksum);
462	if (checksum == GBA_BIOS_CHECKSUM) {
463		mLOG(GBA, INFO, "Official GBA BIOS detected");
464	} else if (checksum == GBA_DS_BIOS_CHECKSUM) {
465		mLOG(GBA, INFO, "Official GBA (DS) BIOS detected");
466	} else {
467		mLOG(GBA, WARN, "BIOS checksum incorrect");
468	}
469	gba->biosChecksum = checksum;
470	if (gba->memory.activeRegion == REGION_BIOS) {
471		gba->cpu->memory.activeRegion = gba->memory.bios;
472	}
473	// TODO: error check
474}
475
476void GBAApplyPatch(struct GBA* gba, struct Patch* patch) {
477	size_t patchedSize = patch->outputSize(patch, gba->memory.romSize);
478	if (!patchedSize || patchedSize > SIZE_CART0) {
479		return;
480	}
481	void* newRom = anonymousMemoryMap(SIZE_CART0);
482	if (!patch->applyPatch(patch, gba->memory.rom, gba->pristineRomSize, newRom, patchedSize)) {
483		mappedMemoryFree(newRom, SIZE_CART0);
484		return;
485	}
486	if (gba->romVf) {
487#ifndef FIXED_ROM_BUFFER
488		gba->romVf->unmap(gba->romVf, gba->memory.rom, gba->pristineRomSize);
489#endif
490		gba->romVf->close(gba->romVf);
491		gba->romVf = NULL;
492	}
493	gba->isPristine = false;
494	gba->memory.rom = newRom;
495	gba->memory.hw.gpioBase = &((uint16_t*) gba->memory.rom)[GPIO_REG_DATA >> 1];
496	gba->memory.romSize = patchedSize;
497	gba->memory.romMask = SIZE_CART0 - 1;
498	gba->romCrc32 = doCrc32(gba->memory.rom, gba->memory.romSize);
499}
500
501void GBARaiseIRQ(struct GBA* gba, enum GBAIRQ irq, uint32_t cyclesLate) {
502	gba->memory.io[REG_IF >> 1] |= 1 << irq;
503	GBATestIRQ(gba, cyclesLate);
504}
505
506void GBATestIRQNoDelay(struct ARMCore* cpu) {
507	struct GBA* gba = (struct GBA*) cpu->master;
508	GBATestIRQ(gba, 0);
509}
510
511void GBATestIRQ(struct GBA* gba, uint32_t cyclesLate) {
512	if (gba->memory.io[REG_IE >> 1] & gba->memory.io[REG_IF >> 1]) {
513		if (!mTimingIsScheduled(&gba->timing, &gba->irqEvent)) {
514			mTimingSchedule(&gba->timing, &gba->irqEvent, GBA_IRQ_DELAY - cyclesLate);
515		}
516	}
517}
518
519void GBAHalt(struct GBA* gba) {
520	gba->cpu->nextEvent = gba->cpu->cycles;
521	gba->cpu->halted = 1;
522}
523
524void GBAStop(struct GBA* gba) {
525	size_t c;
526	for (c = 0; c < mCoreCallbacksListSize(&gba->coreCallbacks); ++c) {
527		struct mCoreCallbacks* callbacks = mCoreCallbacksListGetPointer(&gba->coreCallbacks, c);
528		if (callbacks->sleep) {
529			callbacks->sleep(callbacks->context);
530		}
531	}
532	gba->cpu->nextEvent = gba->cpu->cycles;
533}
534
535void GBADebug(struct GBA* gba, uint16_t flags) {
536	gba->debugFlags = flags;
537	if (GBADebugFlagsIsSend(gba->debugFlags)) {
538		int level = 1 << GBADebugFlagsGetLevel(gba->debugFlags);
539		level &= 0x1F;
540		char oolBuf[0x101];
541		strncpy(oolBuf, gba->debugString, sizeof(oolBuf) - 1);
542		memset(gba->debugString, 0, sizeof(gba->debugString));
543		oolBuf[0x100] = '\0';
544		mLog(_mLOG_CAT_GBA_DEBUG, level, "%s", oolBuf);
545	}
546	gba->debugFlags = GBADebugFlagsClearSend(gba->debugFlags);
547}
548
549bool GBAIsROM(struct VFile* vf) {
550#ifdef USE_ELF
551	struct ELF* elf = ELFOpen(vf);
552	if (elf) {
553		uint32_t entry = ELFEntry(elf);
554		bool isGBA = true;
555		isGBA = isGBA && ELFMachine(elf) == EM_ARM;
556		isGBA = isGBA && (entry == BASE_CART0 || entry == BASE_WORKING_RAM);
557		ELFClose(elf);
558		return isGBA;
559	}
560#endif
561	if (!vf) {
562		return false;
563	}
564
565	uint8_t signature[sizeof(GBA_ROM_MAGIC) + sizeof(GBA_ROM_MAGIC2)];
566	if (vf->seek(vf, GBA_ROM_MAGIC_OFFSET, SEEK_SET) < 0) {
567		return false;
568	}
569	if (vf->read(vf, &signature, sizeof(GBA_ROM_MAGIC)) != sizeof(GBA_ROM_MAGIC)) {
570		return false;
571	}
572	if (memcmp(signature, GBA_ROM_MAGIC, sizeof(GBA_ROM_MAGIC)) != 0) {
573		return false;
574	}
575
576	if (vf->seek(vf, GBA_ROM_MAGIC_OFFSET2, SEEK_SET) < 0) {
577		return false;
578	}
579	if (vf->read(vf, &signature, sizeof(GBA_ROM_MAGIC2)) != sizeof(GBA_ROM_MAGIC2)) {
580		return false;
581	}
582	if (memcmp(signature, GBA_ROM_MAGIC2, sizeof(GBA_ROM_MAGIC2)) != 0) {
583		// If the signature byte is missing then we must be using an unfixed ROM
584		uint32_t buffer[0x9C / sizeof(uint32_t)];
585		if (vf->seek(vf, 0x4, SEEK_SET) < 0) {
586			return false;
587		}
588		if (vf->read(vf, &buffer, sizeof(buffer)) != sizeof(buffer)) {
589			return false;
590		}
591		uint32_t bits = 0;
592		size_t i;
593		for (i = 0; i < sizeof(buffer) / sizeof(*buffer); ++i) {
594			bits |= buffer[i];
595		}
596		if (bits) {
597			return false;
598		}
599	}
600
601
602	if (GBAIsBIOS(vf)) {
603		return false;
604	}
605	return true;
606}
607
608bool GBAIsMB(struct VFile* vf) {
609	if (!GBAIsROM(vf)) {
610		return false;
611	}
612#ifdef USE_ELF
613	struct ELF* elf = ELFOpen(vf);
614	if (elf) {
615		bool isMB = ELFEntry(elf) == BASE_WORKING_RAM;
616		ELFClose(elf);
617		return isMB;
618	}
619#endif
620	if (vf->size(vf) > SIZE_WORKING_RAM) {
621		return false;
622	}
623	if (vf->seek(vf, GBA_MB_MAGIC_OFFSET, SEEK_SET) < 0) {
624		return false;
625	}
626	uint32_t signature;
627	if (vf->read(vf, &signature, sizeof(signature)) != sizeof(signature)) {
628		return false;
629	}
630	uint32_t opcode;
631	LOAD_32(opcode, 0, &signature);
632	struct ARMInstructionInfo info;
633	ARMDecodeARM(opcode, &info);
634	if (info.branchType == ARM_BRANCH) {
635		if (info.op1.immediate <= 0) {
636			return false;
637		} else if (info.op1.immediate == 28) {
638			// Ancient toolchain that is known to throw MB detection for a loop
639			return false;
640		} else if (info.op1.immediate != 24) {
641			return true;
642		}
643	}
644
645	uint32_t pc = GBA_MB_MAGIC_OFFSET;
646	int i;
647	for (i = 0; i < 80; ++i) {
648		if (vf->read(vf, &signature, sizeof(signature)) != sizeof(signature)) {
649			break;
650		}
651		pc += 4;
652		LOAD_32(opcode, 0, &signature);
653		ARMDecodeARM(opcode, &info);
654		if (info.mnemonic != ARM_MN_LDR) {
655			continue;
656		}
657		if ((info.operandFormat & ARM_OPERAND_MEMORY) && info.memory.baseReg == ARM_PC && info.memory.format & ARM_MEMORY_IMMEDIATE_OFFSET) {
658			uint32_t immediate = info.memory.offset.immediate;
659			if (info.memory.format & ARM_MEMORY_OFFSET_SUBTRACT) {
660				immediate = -immediate;
661			}
662			immediate += pc + 8;
663			if (vf->seek(vf, immediate, SEEK_SET) < 0) {
664				break;
665			}
666			if (vf->read(vf, &signature, sizeof(signature)) != sizeof(signature)) {
667				break;
668			}
669			LOAD_32(immediate, 0, &signature);
670			if (vf->seek(vf, pc, SEEK_SET) < 0) {
671				break;
672			}
673			if ((immediate & ~0x7FF) == BASE_WORKING_RAM) {
674				return true;
675			}
676		}
677	}
678	// Found a libgba-linked cart...these are a bit harder to detect.
679	return false;
680}
681
682bool GBAIsBIOS(struct VFile* vf) {
683	if (vf->seek(vf, 0, SEEK_SET) < 0) {
684		return false;
685	}
686	uint8_t interruptTable[7 * 4];
687	if (vf->read(vf, &interruptTable, sizeof(interruptTable)) != sizeof(interruptTable)) {
688		return false;
689	}
690	int i;
691	for (i = 0; i < 7; ++i) {
692		if (interruptTable[4 * i + 3] != 0xEA || interruptTable[4 * i + 2]) {
693			return false;
694		}
695	}
696	return true;
697}
698
699void GBAGetGameCode(const struct GBA* gba, char* out) {
700	memset(out, 0, 8);
701	if (!gba->memory.rom) {
702		return;
703	}
704
705	memcpy(out, "AGB-", 4);
706	memcpy(&out[4], &((struct GBACartridge*) gba->memory.rom)->id, 4);
707}
708
709void GBAGetGameTitle(const struct GBA* gba, char* out) {
710	if (gba->memory.rom) {
711		memcpy(out, &((struct GBACartridge*) gba->memory.rom)->title, 12);
712		return;
713	}
714	if (gba->isPristine && gba->memory.wram) {
715		memcpy(out, &((struct GBACartridge*) gba->memory.wram)->title, 12);
716		return;
717	}
718	strncpy(out, "(BIOS)", 12);
719}
720
721void GBAHitStub(struct ARMCore* cpu, uint32_t opcode) {
722	struct GBA* gba = (struct GBA*) cpu->master;
723	UNUSED(gba);
724#ifdef USE_DEBUGGERS
725	if (gba->debugger) {
726		struct mDebuggerEntryInfo info = {
727			.address = _ARMPCAddress(cpu),
728			.type.bp.opcode = opcode
729		};
730		mDebuggerEnter(gba->debugger->d.p, DEBUGGER_ENTER_ILLEGAL_OP, &info);
731	}
732#endif
733	// TODO: More sensible category?
734	mLOG(GBA, ERROR, "Stub opcode: %08x", opcode);
735}
736
737void GBAIllegal(struct ARMCore* cpu, uint32_t opcode) {
738	struct GBA* gba = (struct GBA*) cpu->master;
739	if (cpu->executionMode == MODE_THUMB && (opcode & 0xFFC0) == 0xE800) {
740		mLOG(GBA, INFO, "Hit Wii U VC opcode: %08x", opcode);
741		return;
742	}
743	if (!gba->yankedRomSize) {
744		// TODO: More sensible category?
745		mLOG(GBA, WARN, "Illegal opcode: %08x", opcode);
746	}
747#ifdef USE_DEBUGGERS
748	if (gba->debugger) {
749		struct mDebuggerEntryInfo info = {
750			.address = _ARMPCAddress(cpu),
751			.type.bp.opcode = opcode
752		};
753		mDebuggerEnter(gba->debugger->d.p, DEBUGGER_ENTER_ILLEGAL_OP, &info);
754	}
755#endif
756	ARMRaiseUndefined(cpu);
757}
758
759void GBABreakpoint(struct ARMCore* cpu, int immediate) {
760	struct GBA* gba = (struct GBA*) cpu->master;
761	if (immediate >= CPU_COMPONENT_MAX) {
762		return;
763	}
764	switch (immediate) {
765#ifdef USE_DEBUGGERS
766	case CPU_COMPONENT_DEBUGGER:
767		if (gba->debugger) {
768			struct mDebuggerEntryInfo info = {
769				.address = _ARMPCAddress(cpu),
770				.type.bp.breakType = BREAKPOINT_SOFTWARE,
771				.pointId = -1
772			};
773			mDebuggerEnter(gba->debugger->d.p, DEBUGGER_ENTER_BREAKPOINT, &info);
774		}
775		break;
776#endif
777	case CPU_COMPONENT_CHEAT_DEVICE:
778		if (gba->cpu->components[CPU_COMPONENT_CHEAT_DEVICE]) {
779			struct mCheatDevice* device = (struct mCheatDevice*) gba->cpu->components[CPU_COMPONENT_CHEAT_DEVICE];
780			struct GBACheatHook* hook = 0;
781			size_t i;
782			for (i = 0; i < mCheatSetsSize(&device->cheats); ++i) {
783				struct GBACheatSet* cheats = (struct GBACheatSet*) *mCheatSetsGetPointer(&device->cheats, i);
784				if (cheats->hook && cheats->hook->address == _ARMPCAddress(cpu)) {
785					mCheatRefresh(device, &cheats->d);
786					hook = cheats->hook;
787				}
788			}
789			if (hook) {
790				ARMRunFake(cpu, hook->patchedOpcode);
791			}
792		}
793		break;
794	default:
795		break;
796	}
797}
798
799void GBAFrameStarted(struct GBA* gba) {
800	GBATestKeypadIRQ(gba);
801
802	if (gba->audio.mixer) {
803		gba->audio.mixer->vblank(gba->audio.mixer);
804	}
805
806	size_t c;
807	for (c = 0; c < mCoreCallbacksListSize(&gba->coreCallbacks); ++c) {
808		struct mCoreCallbacks* callbacks = mCoreCallbacksListGetPointer(&gba->coreCallbacks, c);
809		if (callbacks->videoFrameStarted) {
810			callbacks->videoFrameStarted(callbacks->context);
811		}
812	}
813}
814
815void GBAFrameEnded(struct GBA* gba) {
816	GBASavedataClean(&gba->memory.savedata, gba->video.frameCounter);
817
818	if (gba->cpu->components && gba->cpu->components[CPU_COMPONENT_CHEAT_DEVICE]) {
819		struct mCheatDevice* device = (struct mCheatDevice*) gba->cpu->components[CPU_COMPONENT_CHEAT_DEVICE];
820		size_t i;
821		for (i = 0; i < mCheatSetsSize(&device->cheats); ++i) {
822			struct GBACheatSet* cheats = (struct GBACheatSet*) *mCheatSetsGetPointer(&device->cheats, i);
823			if (!cheats->hook) {
824				mCheatRefresh(device, &cheats->d);
825			}
826		}
827	}
828
829	if (gba->stream && gba->stream->postVideoFrame) {
830		const color_t* pixels;
831		size_t stride;
832		gba->video.renderer->getPixels(gba->video.renderer, &stride, (const void**) &pixels);
833		gba->stream->postVideoFrame(gba->stream, pixels, stride);
834	}
835
836	if (gba->memory.hw.devices & (HW_GB_PLAYER | HW_GB_PLAYER_DETECTION)) {
837		GBAHardwarePlayerUpdate(gba);
838	}
839
840	size_t c;
841	for (c = 0; c < mCoreCallbacksListSize(&gba->coreCallbacks); ++c) {
842		struct mCoreCallbacks* callbacks = mCoreCallbacksListGetPointer(&gba->coreCallbacks, c);
843		if (callbacks->videoFrameEnded) {
844			callbacks->videoFrameEnded(callbacks->context);
845		}
846	}
847}
848
849void GBATestKeypadIRQ(struct GBA* gba) {
850	uint16_t keycnt = gba->memory.io[REG_KEYCNT >> 1];
851	if (!(keycnt & 0x4000)) {
852		return;
853	}
854	int isAnd = keycnt & 0x8000;
855	if (!gba->keySource) {
856		// TODO?
857		return;
858	}
859
860	keycnt &= 0x3FF;
861	uint16_t keyInput = *gba->keySource & keycnt;
862
863	if (isAnd && keycnt == keyInput) {
864		GBARaiseIRQ(gba, IRQ_KEYPAD, 0);
865	} else if (!isAnd && keyInput) {
866		GBARaiseIRQ(gba, IRQ_KEYPAD, 0);
867	}
868}
869
870static void _triggerIRQ(struct mTiming* timing, void* user, uint32_t cyclesLate) {
871	UNUSED(timing);
872	UNUSED(cyclesLate);
873	struct GBA* gba = user;
874	gba->cpu->halted = 0;
875	if (!(gba->memory.io[REG_IE >> 1] & gba->memory.io[REG_IF >> 1])) {
876		return;
877	}
878
879	if (gba->memory.io[REG_IME >> 1] && !gba->cpu->cpsr.i) {
880		ARMRaiseIRQ(gba->cpu);
881	}
882}
883
884void GBASetBreakpoint(struct GBA* gba, struct mCPUComponent* component, uint32_t address, enum ExecutionMode mode, uint32_t* opcode) {
885	size_t immediate;
886	for (immediate = 0; immediate < gba->cpu->numComponents; ++immediate) {
887		if (gba->cpu->components[immediate] == component) {
888			break;
889		}
890	}
891	if (immediate == gba->cpu->numComponents) {
892		return;
893	}
894	if (mode == MODE_ARM) {
895		int32_t value;
896		int32_t old;
897		value = 0xE1200070;
898		value |= immediate & 0xF;
899		value |= (immediate & 0xFFF0) << 4;
900		GBAPatch32(gba->cpu, address, value, &old);
901		*opcode = old;
902	} else {
903		int16_t value;
904		int16_t old;
905		value = 0xBE00;
906		value |= immediate & 0xFF;
907		GBAPatch16(gba->cpu, address, value, &old);
908		*opcode = (uint16_t) old;
909	}
910}
911
912void GBAClearBreakpoint(struct GBA* gba, uint32_t address, enum ExecutionMode mode, uint32_t opcode) {
913	if (mode == MODE_ARM) {
914		GBAPatch32(gba->cpu, address, opcode, 0);
915	} else {
916		GBAPatch16(gba->cpu, address, opcode, 0);
917	}
918}
919
920#ifdef USE_DEBUGGERS
921static bool _setSoftwareBreakpoint(struct ARMDebugger* debugger, uint32_t address, enum ExecutionMode mode, uint32_t* opcode) {
922	GBASetBreakpoint((struct GBA*) debugger->cpu->master, &debugger->d.p->d, address, mode, opcode);
923	return true;
924}
925
926static void _clearSoftwareBreakpoint(struct ARMDebugger* debugger, const struct ARMDebugBreakpoint* breakpoint) {
927	GBAClearBreakpoint((struct GBA*) debugger->cpu->master, breakpoint->d.address, breakpoint->sw.mode, breakpoint->sw.opcode);
928}
929#endif