all repos — mgba @ 45e0eb7013fc8fbc6a819c7d565fc087fb311a7a

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#include <mgba/internal/gba/rr/rr.h>
 17
 18#include <mgba-util/patch.h>
 19#include <mgba-util/crc32.h>
 20#include <mgba-util/math.h>
 21#include <mgba-util/memory.h>
 22#include <mgba-util/vfs.h>
 23
 24#ifdef USE_ELF
 25#include <mgba-util/elf-read.h>
 26#endif
 27
 28#define GBA_IRQ_DELAY 7
 29
 30mLOG_DEFINE_CATEGORY(GBA, "GBA", "gba");
 31mLOG_DEFINE_CATEGORY(GBA_DEBUG, "GBA Debug", "gba.debug");
 32
 33const uint32_t GBA_COMPONENT_MAGIC = 0x1000000;
 34
 35static const size_t GBA_ROM_MAGIC_OFFSET = 3;
 36static const uint8_t GBA_ROM_MAGIC[] = { 0xEA };
 37
 38static const size_t GBA_ROM_MAGIC_OFFSET2 = 0xB2;
 39static const uint8_t GBA_ROM_MAGIC2[] = { 0x96 };
 40
 41static const size_t GBA_MB_MAGIC_OFFSET = 0xC0;
 42
 43static void GBAInit(void* cpu, struct mCPUComponent* component);
 44static void GBAInterruptHandlerInit(struct ARMInterruptHandler* irqh);
 45static void GBAProcessEvents(struct ARMCore* cpu);
 46static void GBAHitStub(struct ARMCore* cpu, uint32_t opcode);
 47static void GBAIllegal(struct ARMCore* cpu, uint32_t opcode);
 48static void GBABreakpoint(struct ARMCore* cpu, int immediate);
 49static void GBATestIRQNoDelay(struct ARMCore* cpu);
 50
 51static void _triggerIRQ(struct mTiming*, void* user, uint32_t cyclesLate);
 52
 53#ifdef USE_DEBUGGERS
 54static bool _setSoftwareBreakpoint(struct ARMDebugger*, uint32_t address, enum ExecutionMode mode, uint32_t* opcode);
 55static bool _clearSoftwareBreakpoint(struct ARMDebugger*, uint32_t address, enum ExecutionMode mode, uint32_t opcode);
 56#endif
 57
 58#ifdef FIXED_ROM_BUFFER
 59extern uint32_t* romBuffer;
 60extern size_t romBufferSize;
 61#endif
 62
 63void GBACreate(struct GBA* gba) {
 64	gba->d.id = GBA_COMPONENT_MAGIC;
 65	gba->d.init = GBAInit;
 66	gba->d.deinit = 0;
 67}
 68
 69static void GBAInit(void* cpu, struct mCPUComponent* component) {
 70	struct GBA* gba = (struct GBA*) component;
 71	gba->cpu = cpu;
 72	gba->debugger = 0;
 73	gba->sync = 0;
 74
 75	GBAInterruptHandlerInit(&gba->cpu->irqh);
 76	GBAMemoryInit(gba);
 77
 78	gba->memory.savedata.timing = &gba->timing;
 79	GBASavedataInit(&gba->memory.savedata, NULL);
 80
 81	gba->video.p = gba;
 82	GBAVideoInit(&gba->video);
 83
 84	gba->audio.p = gba;
 85	GBAAudioInit(&gba->audio, GBA_AUDIO_SAMPLES);
 86
 87	GBAIOInit(gba);
 88
 89	gba->sio.p = gba;
 90	GBASIOInit(&gba->sio);
 91
 92	GBAHardwareInit(&gba->memory.hw, NULL);
 93
 94	gba->keySource = 0;
 95	gba->rotationSource = 0;
 96	gba->luminanceSource = 0;
 97	gba->rtcSource = 0;
 98	gba->rumble = 0;
 99	gba->rr = 0;
100
101	gba->romVf = 0;
102	gba->biosVf = 0;
103
104	gba->stream = NULL;
105	gba->keyCallback = NULL;
106	mCoreCallbacksListInit(&gba->coreCallbacks, 0);
107
108	gba->biosChecksum = GBAChecksum(gba->memory.bios, SIZE_BIOS);
109
110	gba->idleOptimization = IDLE_LOOP_REMOVE;
111	gba->idleLoop = IDLE_LOOP_NONE;
112
113	gba->hardCrash = true;
114	gba->allowOpposingDirections = true;
115
116	gba->performingDMA = false;
117
118	gba->isPristine = false;
119	gba->pristineRomSize = 0;
120	gba->yankedRomSize = 0;
121
122	mTimingInit(&gba->timing, &gba->cpu->cycles, &gba->cpu->nextEvent);
123
124	gba->irqEvent.name = "GBA IRQ Event";
125	gba->irqEvent.callback = _triggerIRQ;
126	gba->irqEvent.context = gba;
127	gba->irqEvent.priority = 0;
128}
129
130void GBAUnloadROM(struct GBA* gba) {
131	if (gba->memory.rom && !gba->isPristine) {
132		if (gba->yankedRomSize) {
133			gba->yankedRomSize = 0;
134		}
135		mappedMemoryFree(gba->memory.rom, SIZE_CART0);
136	}
137
138	if (gba->romVf) {
139#ifndef FIXED_ROM_BUFFER
140		if (gba->isPristine) {
141			gba->romVf->unmap(gba->romVf, gba->memory.rom, gba->pristineRomSize);
142		}
143#endif
144		gba->romVf->close(gba->romVf);
145		gba->romVf = NULL;
146	}
147	gba->memory.rom = NULL;
148	gba->isPristine = false;
149
150	gba->memory.savedata.maskWriteback = false;
151	GBASavedataUnmask(&gba->memory.savedata);
152	GBASavedataDeinit(&gba->memory.savedata);
153	if (gba->memory.savedata.realVf) {
154		gba->memory.savedata.realVf->close(gba->memory.savedata.realVf);
155		gba->memory.savedata.realVf = 0;
156	}
157	gba->idleLoop = IDLE_LOOP_NONE;
158}
159
160void GBADestroy(struct GBA* gba) {
161	GBAUnloadROM(gba);
162
163	if (gba->biosVf) {
164		gba->biosVf->unmap(gba->biosVf, gba->memory.bios, SIZE_BIOS);
165		gba->biosVf->close(gba->biosVf);
166		gba->biosVf = 0;
167	}
168
169	GBAMemoryDeinit(gba);
170	GBAVideoDeinit(&gba->video);
171	GBAAudioDeinit(&gba->audio);
172	GBASIODeinit(&gba->sio);
173	gba->rr = 0;
174	mTimingDeinit(&gba->timing);
175	mCoreCallbacksListDeinit(&gba->coreCallbacks);
176}
177
178void GBAInterruptHandlerInit(struct ARMInterruptHandler* irqh) {
179	irqh->reset = GBAReset;
180	irqh->processEvents = GBAProcessEvents;
181	irqh->swi16 = GBASwi16;
182	irqh->swi32 = GBASwi32;
183	irqh->hitIllegal = GBAIllegal;
184	irqh->readCPSR = GBATestIRQNoDelay;
185	irqh->hitStub = GBAHitStub;
186	irqh->bkpt16 = GBABreakpoint;
187	irqh->bkpt32 = GBABreakpoint;
188}
189
190void GBAReset(struct ARMCore* cpu) {
191	ARMSetPrivilegeMode(cpu, MODE_IRQ);
192	cpu->gprs[ARM_SP] = SP_BASE_IRQ;
193	ARMSetPrivilegeMode(cpu, MODE_SUPERVISOR);
194	cpu->gprs[ARM_SP] = SP_BASE_SUPERVISOR;
195	ARMSetPrivilegeMode(cpu, MODE_SYSTEM);
196	cpu->gprs[ARM_SP] = SP_BASE_SYSTEM;
197
198	struct GBA* gba = (struct GBA*) cpu->master;
199	if (!gba->rr || (!gba->rr->isPlaying(gba->rr) && !gba->rr->isRecording(gba->rr))) {
200		gba->memory.savedata.maskWriteback = false;
201		GBASavedataUnmask(&gba->memory.savedata);
202	}
203
204	gba->cpuBlocked = false;
205	gba->earlyExit = false;
206	if (gba->yankedRomSize) {
207		gba->memory.romSize = gba->yankedRomSize;
208		gba->memory.romMask = toPow2(gba->memory.romSize) - 1;
209		gba->yankedRomSize = 0;
210	}
211	mTimingClear(&gba->timing);
212	GBAMemoryReset(gba);
213	GBAVideoReset(&gba->video);
214	GBAAudioReset(&gba->audio);
215	GBAIOInit(gba);
216	GBATimerInit(gba);
217
218	GBASIOReset(&gba->sio);
219
220	bool isELF = false;
221#ifdef USE_ELF
222	struct ELF* elf = ELFOpen(gba->romVf);
223	if (elf) {
224		isELF = true;
225		ELFClose(elf);
226	}
227#endif
228
229	if (GBAIsMB(gba->romVf) && !isELF) {
230		gba->romVf->seek(gba->romVf, 0, SEEK_SET);
231		gba->romVf->read(gba->romVf, gba->memory.wram, gba->pristineRomSize);
232	}
233
234	gba->lastJump = 0;
235	gba->haltPending = false;
236	gba->idleDetectionStep = 0;
237	gba->idleDetectionFailures = 0;
238
239	gba->debug = false;
240	memset(gba->debugString, 0, sizeof(gba->debugString));
241
242
243	if (gba->romVf && gba->pristineRomSize > SIZE_CART0) {
244		char ident;
245		gba->romVf->seek(gba->romVf, 0xAC, SEEK_SET);
246		gba->romVf->read(gba->romVf, &ident, 1);
247		gba->romVf->seek(gba->romVf, 0, SEEK_SET);
248		if (ident == 'M') {
249			GBAMatrixReset(gba);
250		}
251	}
252}
253
254void GBASkipBIOS(struct GBA* gba) {
255	struct ARMCore* cpu = gba->cpu;
256	if (cpu->gprs[ARM_PC] == BASE_RESET + WORD_SIZE_ARM) {
257		if (gba->memory.rom) {
258			cpu->gprs[ARM_PC] = BASE_CART0;
259		} else {
260			cpu->gprs[ARM_PC] = BASE_WORKING_RAM + 0xC0;
261		}
262		gba->video.vcount = 0x7D;
263		gba->memory.io[REG_VCOUNT >> 1] = 0x7D;
264		gba->memory.io[REG_POSTFLG >> 1] = 1;
265		ARMWritePC(cpu);
266	}
267}
268
269static void GBAProcessEvents(struct ARMCore* cpu) {
270	struct GBA* gba = (struct GBA*) cpu->master;
271
272	gba->bus = cpu->prefetch[1];
273	if (cpu->executionMode == MODE_THUMB) {
274		gba->bus |= cpu->prefetch[1] << 16;
275	}
276
277	int32_t nextEvent = cpu->nextEvent;
278	while (cpu->cycles >= nextEvent) {
279		cpu->nextEvent = INT_MAX;
280		nextEvent = 0;
281		do {
282			int32_t cycles = cpu->cycles;
283			cpu->cycles = 0;
284#ifndef NDEBUG
285			if (cycles < 0) {
286				mLOG(GBA, FATAL, "Negative cycles passed: %i", cycles);
287			}
288#endif
289			nextEvent = mTimingTick(&gba->timing, nextEvent + cycles);
290		} while (gba->cpuBlocked);
291
292		cpu->nextEvent = nextEvent;
293		if (cpu->halted) {
294			cpu->cycles = nextEvent;
295			if (!gba->memory.io[REG_IME >> 1] || !gba->memory.io[REG_IE >> 1]) {
296				break;
297			}
298		}
299#ifndef NDEBUG
300		else if (nextEvent < 0) {
301			mLOG(GBA, FATAL, "Negative cycles will pass: %i", nextEvent);
302		}
303#endif
304		if (gba->earlyExit) {
305			break;
306		}
307	}
308	gba->earlyExit = false;
309#ifndef NDEBUG
310	if (gba->cpuBlocked) {
311		mLOG(GBA, FATAL, "CPU is blocked!");
312	}
313#endif
314}
315
316#ifdef USE_DEBUGGERS
317void GBAAttachDebugger(struct GBA* gba, struct mDebugger* debugger) {
318	gba->debugger = (struct ARMDebugger*) debugger->platform;
319	gba->debugger->setSoftwareBreakpoint = _setSoftwareBreakpoint;
320	gba->debugger->clearSoftwareBreakpoint = _clearSoftwareBreakpoint;
321	gba->cpu->components[CPU_COMPONENT_DEBUGGER] = &debugger->d;
322	ARMHotplugAttach(gba->cpu, CPU_COMPONENT_DEBUGGER);
323}
324
325void GBADetachDebugger(struct GBA* gba) {
326	if (gba->debugger) {
327		ARMHotplugDetach(gba->cpu, CPU_COMPONENT_DEBUGGER);
328	}
329	gba->cpu->components[CPU_COMPONENT_DEBUGGER] = NULL;
330	gba->debugger = NULL;
331}
332#endif
333
334bool GBALoadNull(struct GBA* gba) {
335	GBAUnloadROM(gba);
336	gba->romVf = NULL;
337	gba->pristineRomSize = 0;
338#ifndef FIXED_ROM_BUFFER
339	gba->memory.rom = anonymousMemoryMap(SIZE_CART0);
340#else
341	gba->memory.rom = romBuffer;
342#endif
343	gba->isPristine = false;
344	gba->yankedRomSize = 0;
345	gba->memory.romSize = SIZE_CART0;
346	gba->memory.romMask = SIZE_CART0 - 1;
347	gba->memory.mirroring = false;
348	gba->romCrc32 = 0;
349
350	if (gba->cpu) {
351		gba->cpu->memory.setActiveRegion(gba->cpu, gba->cpu->gprs[ARM_PC]);
352	}
353	GBAHardwareInit(&gba->memory.hw, &((uint16_t*) gba->memory.rom)[GPIO_REG_DATA >> 1]);
354	return true;
355}
356
357bool GBALoadMB(struct GBA* gba, struct VFile* vf) {
358	GBAUnloadROM(gba);
359	gba->romVf = vf;
360	gba->pristineRomSize = vf->size(vf);
361	vf->seek(vf, 0, SEEK_SET);
362	if (gba->pristineRomSize > SIZE_WORKING_RAM) {
363		gba->pristineRomSize = SIZE_WORKING_RAM;
364	}
365	gba->isPristine = true;
366	memset(gba->memory.wram, 0, SIZE_WORKING_RAM);
367	gba->yankedRomSize = 0;
368	gba->memory.romSize = 0;
369	gba->memory.romMask = 0;
370	gba->romCrc32 = doCrc32(gba->memory.wram, gba->pristineRomSize);
371	if (gba->cpu && gba->memory.activeRegion == REGION_WORKING_RAM) {
372		gba->cpu->memory.setActiveRegion(gba->cpu, gba->cpu->gprs[ARM_PC]);
373	}
374	return true;
375}
376
377bool GBALoadROM(struct GBA* gba, struct VFile* vf) {
378	if (!vf) {
379		return false;
380	}
381	GBAUnloadROM(gba);
382	gba->romVf = vf;
383	gba->pristineRomSize = vf->size(vf);
384	vf->seek(vf, 0, SEEK_SET);
385	if (gba->pristineRomSize > SIZE_CART0) {
386		gba->isPristine = false;
387		char ident;
388		vf->seek(vf, 0xAC, SEEK_SET);
389		vf->read(vf, &ident, 1);
390		if (ident == 'M') {
391			gba->memory.romSize = 0x01000000;
392#ifdef FIXED_ROM_BUFFER
393			gba->memory.rom = romBuffer;
394#else
395			gba->memory.rom = anonymousMemoryMap(SIZE_CART0);
396#endif
397		} else {
398			gba->memory.rom = vf->map(vf, SIZE_CART0, MAP_READ);
399			gba->memory.romSize = SIZE_CART0;
400		}
401	} else {
402		gba->isPristine = true;
403		gba->memory.rom = vf->map(vf, gba->pristineRomSize, MAP_READ);
404		gba->memory.romSize = gba->pristineRomSize;
405	}
406	if (!gba->memory.rom) {
407		mLOG(GBA, WARN, "Couldn't map ROM");
408		return false;
409	}
410	gba->yankedRomSize = 0;
411	gba->memory.romMask = toPow2(gba->memory.romSize) - 1;
412	gba->memory.mirroring = false;
413	gba->romCrc32 = doCrc32(gba->memory.rom, gba->memory.romSize);
414	if (popcount32(gba->memory.romSize) != 1) {
415		// This ROM is either a bad dump or homebrew. Emulate flash cart behavior.
416#ifndef FIXED_ROM_BUFFER
417		void* newRom = anonymousMemoryMap(SIZE_CART0);
418		memcpy(newRom, gba->memory.rom, gba->pristineRomSize);
419		gba->memory.rom = newRom;
420#endif
421		gba->memory.romSize = SIZE_CART0;
422		gba->memory.romMask = SIZE_CART0 - 1;
423		gba->isPristine = false;
424	}
425	if (gba->cpu && gba->memory.activeRegion >= REGION_CART0) {
426		gba->cpu->memory.setActiveRegion(gba->cpu, gba->cpu->gprs[ARM_PC]);
427	}
428	GBAHardwareInit(&gba->memory.hw, &((uint16_t*) gba->memory.rom)[GPIO_REG_DATA >> 1]);
429	GBAVFameDetect(&gba->memory.vfame, gba->memory.rom, gba->memory.romSize);
430	// TODO: error check
431	return true;
432}
433
434bool GBALoadSave(struct GBA* gba, struct VFile* sav) {
435	GBASavedataInit(&gba->memory.savedata, sav);
436	return true;
437}
438
439void GBAYankROM(struct GBA* gba) {
440	gba->yankedRomSize = gba->memory.romSize;
441	gba->memory.romSize = 0;
442	gba->memory.romMask = 0;
443	GBARaiseIRQ(gba, IRQ_GAMEPAK, 0);
444}
445
446void GBALoadBIOS(struct GBA* gba, struct VFile* vf) {
447	gba->biosVf = vf;
448	if (vf->size(vf) != SIZE_BIOS) {
449		mLOG(GBA, WARN, "Incorrect BIOS size");
450		return;
451	}
452	uint32_t* bios = vf->map(vf, SIZE_BIOS, MAP_READ);
453	if (!bios) {
454		mLOG(GBA, WARN, "Couldn't map BIOS");
455		return;
456	}
457	gba->memory.bios = bios;
458	gba->memory.fullBios = 1;
459	uint32_t checksum = GBAChecksum(gba->memory.bios, SIZE_BIOS);
460	mLOG(GBA, DEBUG, "BIOS Checksum: 0x%X", checksum);
461	if (checksum == GBA_BIOS_CHECKSUM) {
462		mLOG(GBA, INFO, "Official GBA BIOS detected");
463	} else if (checksum == GBA_DS_BIOS_CHECKSUM) {
464		mLOG(GBA, INFO, "Official GBA (DS) BIOS detected");
465	} else {
466		mLOG(GBA, WARN, "BIOS checksum incorrect");
467	}
468	gba->biosChecksum = checksum;
469	if (gba->memory.activeRegion == REGION_BIOS) {
470		gba->cpu->memory.activeRegion = gba->memory.bios;
471	}
472	// TODO: error check
473}
474
475void GBAApplyPatch(struct GBA* gba, struct Patch* patch) {
476	size_t patchedSize = patch->outputSize(patch, gba->memory.romSize);
477	if (!patchedSize || patchedSize > SIZE_CART0) {
478		return;
479	}
480	void* newRom = anonymousMemoryMap(SIZE_CART0);
481	if (!patch->applyPatch(patch, gba->memory.rom, gba->pristineRomSize, newRom, patchedSize)) {
482		mappedMemoryFree(newRom, SIZE_CART0);
483		return;
484	}
485	if (gba->romVf) {
486#ifndef FIXED_ROM_BUFFER
487		gba->romVf->unmap(gba->romVf, gba->memory.rom, gba->pristineRomSize);
488#endif
489		gba->romVf->close(gba->romVf);
490		gba->romVf = NULL;
491	}
492	gba->isPristine = false;
493	gba->memory.rom = newRom;
494	gba->memory.hw.gpioBase = &((uint16_t*) gba->memory.rom)[GPIO_REG_DATA >> 1];
495	gba->memory.romSize = patchedSize;
496	gba->memory.romMask = SIZE_CART0 - 1;
497	gba->romCrc32 = doCrc32(gba->memory.rom, gba->memory.romSize);
498}
499
500void GBARaiseIRQ(struct GBA* gba, enum GBAIRQ irq, uint32_t cyclesLate) {
501	gba->memory.io[REG_IF >> 1] |= 1 << irq;
502	GBATestIRQ(gba, cyclesLate);
503}
504
505void GBATestIRQNoDelay(struct ARMCore* cpu) {
506	struct GBA* gba = (struct GBA*) cpu->master;
507	GBATestIRQ(gba, 0);
508}
509
510void GBATestIRQ(struct GBA* gba, uint32_t cyclesLate) {
511	if (gba->memory.io[REG_IE >> 1] & gba->memory.io[REG_IF >> 1]) {
512		if (!mTimingIsScheduled(&gba->timing, &gba->irqEvent)) {
513			mTimingSchedule(&gba->timing, &gba->irqEvent, GBA_IRQ_DELAY - cyclesLate);
514		}
515	}
516}
517
518void GBAHalt(struct GBA* gba) {
519	gba->cpu->nextEvent = gba->cpu->cycles;
520	gba->cpu->halted = 1;
521}
522
523void GBAStop(struct GBA* gba) {
524	size_t c;
525	for (c = 0; c < mCoreCallbacksListSize(&gba->coreCallbacks); ++c) {
526		struct mCoreCallbacks* callbacks = mCoreCallbacksListGetPointer(&gba->coreCallbacks, c);
527		if (callbacks->sleep) {
528			callbacks->sleep(callbacks->context);
529		}
530	}
531	gba->cpu->nextEvent = gba->cpu->cycles;
532}
533
534void GBADebug(struct GBA* gba, uint16_t flags) {
535	gba->debugFlags = flags;
536	if (GBADebugFlagsIsSend(gba->debugFlags)) {
537		int level = 1 << GBADebugFlagsGetLevel(gba->debugFlags);
538		level &= 0x1F;
539		char oolBuf[0x101];
540		strncpy(oolBuf, gba->debugString, sizeof(oolBuf) - 1);
541		memset(gba->debugString, 0, sizeof(gba->debugString));
542		oolBuf[0x100] = '\0';
543		mLog(_mLOG_CAT_GBA_DEBUG, level, "%s", oolBuf);
544	}
545	gba->debugFlags = GBADebugFlagsClearSend(gba->debugFlags);
546}
547
548bool GBAIsROM(struct VFile* vf) {
549#ifdef USE_ELF
550	struct ELF* elf = ELFOpen(vf);
551	if (elf) {
552		uint32_t entry = ELFEntry(elf);
553		bool isGBA = true;
554		isGBA = isGBA && ELFMachine(elf) == EM_ARM;
555		isGBA = isGBA && (entry == BASE_CART0 || entry == BASE_WORKING_RAM);
556		ELFClose(elf);
557		return isGBA;
558	}
559#endif
560	if (!vf) {
561		return false;
562	}
563
564	uint8_t signature[sizeof(GBA_ROM_MAGIC) + sizeof(GBA_ROM_MAGIC2)];
565	if (vf->seek(vf, GBA_ROM_MAGIC_OFFSET, SEEK_SET) < 0) {
566		return false;
567	}
568	if (vf->read(vf, &signature, sizeof(GBA_ROM_MAGIC)) != sizeof(GBA_ROM_MAGIC)) {
569		return false;
570	}
571	if (memcmp(signature, GBA_ROM_MAGIC, sizeof(GBA_ROM_MAGIC)) != 0) {
572		return false;
573	}
574
575	if (vf->seek(vf, GBA_ROM_MAGIC_OFFSET2, SEEK_SET) < 0) {
576		return false;
577	}
578	if (vf->read(vf, &signature, sizeof(GBA_ROM_MAGIC2)) != sizeof(GBA_ROM_MAGIC2)) {
579		return false;
580	}
581	if (memcmp(signature, GBA_ROM_MAGIC2, sizeof(GBA_ROM_MAGIC2)) != 0) {
582		// If the signature byte is missing then we must be using an unfixed ROM
583		uint32_t buffer[0x9C / sizeof(uint32_t)];
584		if (vf->seek(vf, 0x4, SEEK_SET) < 0) {
585			return false;
586		}
587		if (vf->read(vf, &buffer, sizeof(buffer)) != sizeof(buffer)) {
588			return false;
589		}
590		uint32_t bits = 0;
591		size_t i;
592		for (i = 0; i < sizeof(buffer) / sizeof(*buffer); ++i) {
593			bits |= buffer[i];
594		}
595		if (bits) {
596			return false;
597		}
598	}
599
600
601	if (GBAIsBIOS(vf)) {
602		return false;
603	}
604	return true;
605}
606
607bool GBAIsMB(struct VFile* vf) {
608	if (!GBAIsROM(vf)) {
609		return false;
610	}
611#ifdef USE_ELF
612	struct ELF* elf = ELFOpen(vf);
613	if (elf) {
614		bool isMB = ELFEntry(elf) == BASE_WORKING_RAM;
615		ELFClose(elf);
616		return isMB;
617	}
618#endif
619	if (vf->size(vf) > SIZE_WORKING_RAM) {
620		return false;
621	}
622	if (vf->seek(vf, GBA_MB_MAGIC_OFFSET, SEEK_SET) < 0) {
623		return false;
624	}
625	uint32_t signature;
626	if (vf->read(vf, &signature, sizeof(signature)) != sizeof(signature)) {
627		return false;
628	}
629	uint32_t opcode;
630	LOAD_32(opcode, 0, &signature);
631	struct ARMInstructionInfo info;
632	ARMDecodeARM(opcode, &info);
633	if (info.branchType == ARM_BRANCH) {
634		if (info.op1.immediate <= 0) {
635			return false;
636		} else if (info.op1.immediate == 28) {
637			// Ancient toolchain that is known to throw MB detection for a loop
638			return false;
639		} else if (info.op1.immediate != 24) {
640			return true;
641		}
642	}
643
644	uint32_t pc = GBA_MB_MAGIC_OFFSET;
645	int i;
646	for (i = 0; i < 80; ++i) {
647		if (vf->read(vf, &signature, sizeof(signature)) != sizeof(signature)) {
648			break;
649		}
650		pc += 4;
651		LOAD_32(opcode, 0, &signature);
652		ARMDecodeARM(opcode, &info);
653		if (info.mnemonic != ARM_MN_LDR) {
654			continue;
655		}
656		if ((info.operandFormat & ARM_OPERAND_MEMORY) && info.memory.baseReg == ARM_PC && info.memory.format & ARM_MEMORY_IMMEDIATE_OFFSET) {
657			uint32_t immediate = info.memory.offset.immediate;
658			if (info.memory.format & ARM_MEMORY_OFFSET_SUBTRACT) {
659				immediate = -immediate;
660			}
661			immediate += pc + 8;
662			if (vf->seek(vf, immediate, SEEK_SET) < 0) {
663				break;
664			}
665			if (vf->read(vf, &signature, sizeof(signature)) != sizeof(signature)) {
666				break;
667			}
668			LOAD_32(immediate, 0, &signature);
669			if (vf->seek(vf, pc, SEEK_SET) < 0) {
670				break;
671			}
672			if ((immediate & ~0x7FF) == BASE_WORKING_RAM) {
673				return true;
674			}
675		}
676	}
677	// Found a libgba-linked cart...these are a bit harder to detect.
678	return false;
679}
680
681bool GBAIsBIOS(struct VFile* vf) {
682	if (vf->seek(vf, 0, SEEK_SET) < 0) {
683		return false;
684	}
685	uint8_t interruptTable[7 * 4];
686	if (vf->read(vf, &interruptTable, sizeof(interruptTable)) != sizeof(interruptTable)) {
687		return false;
688	}
689	int i;
690	for (i = 0; i < 7; ++i) {
691		if (interruptTable[4 * i + 3] != 0xEA || interruptTable[4 * i + 2]) {
692			return false;
693		}
694	}
695	return true;
696}
697
698void GBAGetGameCode(const struct GBA* gba, char* out) {
699	memset(out, 0, 8);
700	if (!gba->memory.rom) {
701		return;
702	}
703
704	memcpy(out, "AGB-", 4);
705	memcpy(&out[4], &((struct GBACartridge*) gba->memory.rom)->id, 4);
706}
707
708void GBAGetGameTitle(const struct GBA* gba, char* out) {
709	if (gba->memory.rom) {
710		memcpy(out, &((struct GBACartridge*) gba->memory.rom)->title, 12);
711		return;
712	}
713	if (gba->isPristine && gba->memory.wram) {
714		memcpy(out, &((struct GBACartridge*) gba->memory.wram)->title, 12);
715		return;
716	}
717	strncpy(out, "(BIOS)", 12);
718}
719
720void GBAHitStub(struct ARMCore* cpu, uint32_t opcode) {
721	struct GBA* gba = (struct GBA*) cpu->master;
722	UNUSED(gba);
723#ifdef USE_DEBUGGERS
724	if (gba->debugger) {
725		struct mDebuggerEntryInfo info = {
726			.address = _ARMPCAddress(cpu),
727			.type.bp.opcode = opcode
728		};
729		mDebuggerEnter(gba->debugger->d.p, DEBUGGER_ENTER_ILLEGAL_OP, &info);
730	}
731#endif
732	// TODO: More sensible category?
733	mLOG(GBA, ERROR, "Stub opcode: %08x", opcode);
734}
735
736void GBAIllegal(struct ARMCore* cpu, uint32_t opcode) {
737	struct GBA* gba = (struct GBA*) cpu->master;
738	if (!gba->yankedRomSize) {
739		// TODO: More sensible category?
740		mLOG(GBA, WARN, "Illegal opcode: %08x", opcode);
741	}
742	if (cpu->executionMode == MODE_THUMB && (opcode & 0xFFC0) == 0xE800) {
743		mLOG(GBA, DEBUG, "Hit Wii U VC opcode: %08x", opcode);
744		return;
745	}
746#ifdef USE_DEBUGGERS
747	if (gba->debugger) {
748		struct mDebuggerEntryInfo info = {
749			.address = _ARMPCAddress(cpu),
750			.type.bp.opcode = opcode
751		};
752		mDebuggerEnter(gba->debugger->d.p, DEBUGGER_ENTER_ILLEGAL_OP, &info);
753	} else
754#endif
755	{
756		ARMRaiseUndefined(cpu);
757	}
758}
759
760void GBABreakpoint(struct ARMCore* cpu, int immediate) {
761	struct GBA* gba = (struct GBA*) cpu->master;
762	if (immediate >= CPU_COMPONENT_MAX) {
763		return;
764	}
765	switch (immediate) {
766#ifdef USE_DEBUGGERS
767	case CPU_COMPONENT_DEBUGGER:
768		if (gba->debugger) {
769			struct mDebuggerEntryInfo info = {
770				.address = _ARMPCAddress(cpu),
771				.type.bp.breakType = BREAKPOINT_SOFTWARE,
772				.pointId = -1
773			};
774			mDebuggerEnter(gba->debugger->d.p, DEBUGGER_ENTER_BREAKPOINT, &info);
775		}
776		break;
777#endif
778	case CPU_COMPONENT_CHEAT_DEVICE:
779		if (gba->cpu->components[CPU_COMPONENT_CHEAT_DEVICE]) {
780			struct mCheatDevice* device = (struct mCheatDevice*) gba->cpu->components[CPU_COMPONENT_CHEAT_DEVICE];
781			struct GBACheatHook* hook = 0;
782			size_t i;
783			for (i = 0; i < mCheatSetsSize(&device->cheats); ++i) {
784				struct GBACheatSet* cheats = (struct GBACheatSet*) *mCheatSetsGetPointer(&device->cheats, i);
785				if (cheats->hook && cheats->hook->address == _ARMPCAddress(cpu)) {
786					mCheatRefresh(device, &cheats->d);
787					hook = cheats->hook;
788				}
789			}
790			if (hook) {
791				ARMRunFake(cpu, hook->patchedOpcode);
792			}
793		}
794		break;
795	default:
796		break;
797	}
798}
799
800void GBAFrameStarted(struct GBA* gba) {
801	GBATestKeypadIRQ(gba);
802
803	if (gba->audio.mixer) {
804		gba->audio.mixer->vblank(gba->audio.mixer);
805	}
806
807	size_t c;
808	for (c = 0; c < mCoreCallbacksListSize(&gba->coreCallbacks); ++c) {
809		struct mCoreCallbacks* callbacks = mCoreCallbacksListGetPointer(&gba->coreCallbacks, c);
810		if (callbacks->videoFrameStarted) {
811			callbacks->videoFrameStarted(callbacks->context);
812		}
813	}
814}
815
816void GBAFrameEnded(struct GBA* gba) {
817	GBASavedataClean(&gba->memory.savedata, gba->video.frameCounter);
818
819	if (gba->rr) {
820		gba->rr->nextFrame(gba->rr);
821	}
822
823	if (gba->cpu->components && gba->cpu->components[CPU_COMPONENT_CHEAT_DEVICE]) {
824		struct mCheatDevice* device = (struct mCheatDevice*) gba->cpu->components[CPU_COMPONENT_CHEAT_DEVICE];
825		size_t i;
826		for (i = 0; i < mCheatSetsSize(&device->cheats); ++i) {
827			struct GBACheatSet* cheats = (struct GBACheatSet*) *mCheatSetsGetPointer(&device->cheats, i);
828			if (!cheats->hook) {
829				mCheatRefresh(device, &cheats->d);
830			}
831		}
832	}
833
834	if (gba->stream && gba->stream->postVideoFrame) {
835		const color_t* pixels;
836		size_t stride;
837		gba->video.renderer->getPixels(gba->video.renderer, &stride, (const void**) &pixels);
838		gba->stream->postVideoFrame(gba->stream, pixels, stride);
839	}
840
841	if (gba->memory.hw.devices & (HW_GB_PLAYER | HW_GB_PLAYER_DETECTION)) {
842		GBAHardwarePlayerUpdate(gba);
843	}
844
845	size_t c;
846	for (c = 0; c < mCoreCallbacksListSize(&gba->coreCallbacks); ++c) {
847		struct mCoreCallbacks* callbacks = mCoreCallbacksListGetPointer(&gba->coreCallbacks, c);
848		if (callbacks->videoFrameEnded) {
849			callbacks->videoFrameEnded(callbacks->context);
850		}
851	}
852}
853
854void GBATestKeypadIRQ(struct GBA* gba) {
855	uint16_t keycnt = gba->memory.io[REG_KEYCNT >> 1];
856	if (!(keycnt & 0x4000)) {
857		return;
858	}
859	int isAnd = keycnt & 0x8000;
860	if (!gba->keySource) {
861		// TODO?
862		return;
863	}
864
865	keycnt &= 0x3FF;
866	uint16_t keyInput = *gba->keySource & keycnt;
867
868	if (isAnd && keycnt == keyInput) {
869		GBARaiseIRQ(gba, IRQ_KEYPAD, 0);
870	} else if (!isAnd && keyInput) {
871		GBARaiseIRQ(gba, IRQ_KEYPAD, 0);
872	}
873}
874
875static void _triggerIRQ(struct mTiming* timing, void* user, uint32_t cyclesLate) {
876	UNUSED(timing);
877	UNUSED(cyclesLate);
878	struct GBA* gba = user;
879	gba->cpu->halted = 0;
880	if (!(gba->memory.io[REG_IE >> 1] & gba->memory.io[REG_IF >> 1])) {
881		return;
882	}
883
884	if (gba->memory.io[REG_IME >> 1] && !gba->cpu->cpsr.i) {
885		ARMRaiseIRQ(gba->cpu);
886	}
887}
888
889void GBASetBreakpoint(struct GBA* gba, struct mCPUComponent* component, uint32_t address, enum ExecutionMode mode, uint32_t* opcode) {
890	size_t immediate;
891	for (immediate = 0; immediate < gba->cpu->numComponents; ++immediate) {
892		if (gba->cpu->components[immediate] == component) {
893			break;
894		}
895	}
896	if (immediate == gba->cpu->numComponents) {
897		return;
898	}
899	if (mode == MODE_ARM) {
900		int32_t value;
901		int32_t old;
902		value = 0xE1200070;
903		value |= immediate & 0xF;
904		value |= (immediate & 0xFFF0) << 4;
905		GBAPatch32(gba->cpu, address, value, &old);
906		*opcode = old;
907	} else {
908		int16_t value;
909		int16_t old;
910		value = 0xBE00;
911		value |= immediate & 0xFF;
912		GBAPatch16(gba->cpu, address, value, &old);
913		*opcode = (uint16_t) old;
914	}
915}
916
917void GBAClearBreakpoint(struct GBA* gba, uint32_t address, enum ExecutionMode mode, uint32_t opcode) {
918	if (mode == MODE_ARM) {
919		GBAPatch32(gba->cpu, address, opcode, 0);
920	} else {
921		GBAPatch16(gba->cpu, address, opcode, 0);
922	}
923}
924
925#ifdef USE_DEBUGGERS
926static bool _setSoftwareBreakpoint(struct ARMDebugger* debugger, uint32_t address, enum ExecutionMode mode, uint32_t* opcode) {
927	GBASetBreakpoint((struct GBA*) debugger->cpu->master, &debugger->d.p->d, address, mode, opcode);
928	return true;
929}
930
931static bool _clearSoftwareBreakpoint(struct ARMDebugger* debugger, uint32_t address, enum ExecutionMode mode, uint32_t opcode) {
932	GBAClearBreakpoint((struct GBA*) debugger->cpu->master, address, mode, opcode);
933	return true;
934}
935#endif