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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#if !defined(FIXED_ROM_BUFFER) && !defined(__wii__)
134		mappedMemoryFree(gba->memory.rom, SIZE_CART0);
135#endif
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	mTimingDeinit(&gba->timing);
174	mCoreCallbacksListDeinit(&gba->coreCallbacks);
175}
176
177void GBAInterruptHandlerInit(struct ARMInterruptHandler* irqh) {
178	irqh->reset = GBAReset;
179	irqh->processEvents = GBAProcessEvents;
180	irqh->swi16 = GBASwi16;
181	irqh->swi32 = GBASwi32;
182	irqh->hitIllegal = GBAIllegal;
183	irqh->readCPSR = GBATestIRQNoDelay;
184	irqh->hitStub = GBAHitStub;
185	irqh->bkpt16 = GBABreakpoint;
186	irqh->bkpt32 = GBABreakpoint;
187}
188
189void GBAReset(struct ARMCore* cpu) {
190	ARMSetPrivilegeMode(cpu, MODE_IRQ);
191	cpu->gprs[ARM_SP] = SP_BASE_IRQ;
192	ARMSetPrivilegeMode(cpu, MODE_SUPERVISOR);
193	cpu->gprs[ARM_SP] = SP_BASE_SUPERVISOR;
194	ARMSetPrivilegeMode(cpu, MODE_SYSTEM);
195	cpu->gprs[ARM_SP] = SP_BASE_SYSTEM;
196
197	struct GBA* gba = (struct GBA*) cpu->master;
198	gba->memory.savedata.maskWriteback = false;
199	GBASavedataUnmask(&gba->memory.savedata);
200
201	gba->cpuBlocked = false;
202	gba->earlyExit = false;
203	gba->dmaPC = 0;
204	gba->biosStall = 0;
205	if (gba->yankedRomSize) {
206		gba->memory.romSize = gba->yankedRomSize;
207		gba->memory.romMask = toPow2(gba->memory.romSize) - 1;
208		gba->yankedRomSize = 0;
209	}
210	mTimingClear(&gba->timing);
211	GBAMemoryReset(gba);
212	GBAVideoReset(&gba->video);
213	GBAAudioReset(&gba->audio);
214	GBAIOInit(gba);
215	GBATimerInit(gba);
216
217	GBASIOReset(&gba->sio);
218
219	bool isELF = false;
220#ifdef USE_ELF
221	struct ELF* elf = ELFOpen(gba->romVf);
222	if (elf) {
223		isELF = true;
224		ELFClose(elf);
225	}
226#endif
227
228	if (GBAIsMB(gba->romVf) && !isELF) {
229		gba->romVf->seek(gba->romVf, 0, SEEK_SET);
230		gba->romVf->read(gba->romVf, gba->memory.wram, gba->pristineRomSize);
231	}
232
233	gba->lastJump = 0;
234	gba->haltPending = false;
235	gba->idleDetectionStep = 0;
236	gba->idleDetectionFailures = 0;
237
238	gba->debug = false;
239	memset(gba->debugString, 0, sizeof(gba->debugString));
240
241
242	if (gba->romVf && gba->pristineRomSize > SIZE_CART0) {
243		char ident;
244		gba->romVf->seek(gba->romVf, 0xAC, SEEK_SET);
245		gba->romVf->read(gba->romVf, &ident, 1);
246		gba->romVf->seek(gba->romVf, 0, SEEK_SET);
247		if (ident == 'M') {
248			GBAMatrixReset(gba);
249		}
250	}
251}
252
253void GBASkipBIOS(struct GBA* gba) {
254	struct ARMCore* cpu = gba->cpu;
255	if (cpu->gprs[ARM_PC] == BASE_RESET + WORD_SIZE_ARM) {
256		if (gba->memory.rom) {
257			cpu->gprs[ARM_PC] = BASE_CART0;
258		} else {
259			cpu->gprs[ARM_PC] = BASE_WORKING_RAM + 0xC0;
260		}
261		gba->video.vcount = 0x7D;
262		gba->memory.io[REG_VCOUNT >> 1] = 0x7D;
263		gba->memory.io[REG_POSTFLG >> 1] = 1;
264		ARMWritePC(cpu);
265	}
266}
267
268static void GBAProcessEvents(struct ARMCore* cpu) {
269	struct GBA* gba = (struct GBA*) cpu->master;
270
271	gba->bus = cpu->prefetch[1];
272	if (cpu->executionMode == MODE_THUMB) {
273		gba->bus |= cpu->prefetch[1] << 16;
274	}
275
276	int32_t nextEvent = cpu->nextEvent;
277	while (cpu->cycles >= nextEvent) {
278		cpu->nextEvent = INT_MAX;
279		nextEvent = 0;
280		do {
281			int32_t cycles = cpu->cycles;
282			cpu->cycles = 0;
283#ifdef USE_DEBUGGERS
284			gba->timing.globalCycles += cycles;
285#endif
286#ifndef NDEBUG
287			if (cycles < 0) {
288				mLOG(GBA, FATAL, "Negative cycles passed: %i", cycles);
289			}
290#endif
291			nextEvent = mTimingTick(&gba->timing, cycles < nextEvent ? nextEvent : cycles);
292		} while (gba->cpuBlocked && !gba->earlyExit);
293
294		cpu->nextEvent = nextEvent;
295		if (cpu->halted) {
296			cpu->cycles = nextEvent;
297			if (!gba->memory.io[REG_IME >> 1] || !gba->memory.io[REG_IE >> 1]) {
298				break;
299			}
300		}
301#ifndef NDEBUG
302		else if (nextEvent < 0) {
303			mLOG(GBA, FATAL, "Negative cycles will pass: %i", nextEvent);
304		}
305#endif
306		if (gba->earlyExit) {
307			break;
308		}
309	}
310	gba->earlyExit = false;
311	if (gba->cpuBlocked) {
312		cpu->cycles = cpu->nextEvent;
313	}
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 sav;
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	if (vf->size(vf) != SIZE_BIOS) {
448		mLOG(GBA, WARN, "Incorrect BIOS size");
449		return;
450	}
451	uint32_t* bios = vf->map(vf, SIZE_BIOS, MAP_READ);
452	if (!bios) {
453		mLOG(GBA, WARN, "Couldn't map BIOS");
454		return;
455	}
456	if (gba->biosVf) {
457		gba->biosVf->unmap(gba->biosVf, gba->memory.bios, SIZE_BIOS);
458		gba->biosVf->close(gba->biosVf);
459	}
460	gba->biosVf = vf;
461	gba->memory.bios = bios;
462	gba->memory.fullBios = 1;
463	uint32_t checksum = GBAChecksum(gba->memory.bios, SIZE_BIOS);
464	mLOG(GBA, DEBUG, "BIOS Checksum: 0x%X", checksum);
465	if (checksum == GBA_BIOS_CHECKSUM) {
466		mLOG(GBA, INFO, "Official GBA BIOS detected");
467	} else if (checksum == GBA_DS_BIOS_CHECKSUM) {
468		mLOG(GBA, INFO, "Official GBA (DS) BIOS detected");
469	} else {
470		mLOG(GBA, WARN, "BIOS checksum incorrect");
471	}
472	gba->biosChecksum = checksum;
473	if (gba->memory.activeRegion == REGION_BIOS) {
474		gba->cpu->memory.activeRegion = gba->memory.bios;
475	}
476	// TODO: error check
477}
478
479void GBAApplyPatch(struct GBA* gba, struct Patch* patch) {
480	size_t patchedSize = patch->outputSize(patch, gba->memory.romSize);
481	if (!patchedSize || patchedSize > SIZE_CART0) {
482		return;
483	}
484	void* newRom = anonymousMemoryMap(SIZE_CART0);
485	if (!patch->applyPatch(patch, gba->memory.rom, gba->pristineRomSize, newRom, patchedSize)) {
486		mappedMemoryFree(newRom, SIZE_CART0);
487		return;
488	}
489	if (gba->romVf) {
490#ifndef FIXED_ROM_BUFFER
491		gba->romVf->unmap(gba->romVf, gba->memory.rom, gba->pristineRomSize);
492#endif
493		gba->romVf->close(gba->romVf);
494		gba->romVf = NULL;
495	}
496	gba->isPristine = false;
497	gba->memory.rom = newRom;
498	gba->memory.hw.gpioBase = &((uint16_t*) gba->memory.rom)[GPIO_REG_DATA >> 1];
499	gba->memory.romSize = patchedSize;
500	gba->memory.romMask = SIZE_CART0 - 1;
501	gba->romCrc32 = doCrc32(gba->memory.rom, gba->memory.romSize);
502}
503
504void GBARaiseIRQ(struct GBA* gba, enum GBAIRQ irq, uint32_t cyclesLate) {
505	gba->memory.io[REG_IF >> 1] |= 1 << irq;
506	GBATestIRQ(gba, cyclesLate);
507}
508
509void GBATestIRQNoDelay(struct ARMCore* cpu) {
510	struct GBA* gba = (struct GBA*) cpu->master;
511	GBATestIRQ(gba, 0);
512}
513
514void GBATestIRQ(struct GBA* gba, uint32_t cyclesLate) {
515	if (gba->memory.io[REG_IE >> 1] & gba->memory.io[REG_IF >> 1]) {
516		if (!mTimingIsScheduled(&gba->timing, &gba->irqEvent)) {
517			mTimingSchedule(&gba->timing, &gba->irqEvent, GBA_IRQ_DELAY - cyclesLate);
518		}
519	}
520}
521
522void GBAHalt(struct GBA* gba) {
523	gba->cpu->nextEvent = gba->cpu->cycles;
524	gba->cpu->halted = 1;
525}
526
527void GBAStop(struct GBA* gba) {
528	size_t c;
529	for (c = 0; c < mCoreCallbacksListSize(&gba->coreCallbacks); ++c) {
530		struct mCoreCallbacks* callbacks = mCoreCallbacksListGetPointer(&gba->coreCallbacks, c);
531		if (callbacks->sleep) {
532			callbacks->sleep(callbacks->context);
533		}
534	}
535	gba->cpu->nextEvent = gba->cpu->cycles;
536}
537
538void GBADebug(struct GBA* gba, uint16_t flags) {
539	gba->debugFlags = flags;
540	if (GBADebugFlagsIsSend(gba->debugFlags)) {
541		int level = 1 << GBADebugFlagsGetLevel(gba->debugFlags);
542		level &= 0x1F;
543		char oolBuf[0x101];
544		strncpy(oolBuf, gba->debugString, sizeof(oolBuf) - 1);
545		memset(gba->debugString, 0, sizeof(gba->debugString));
546		oolBuf[0x100] = '\0';
547		mLog(_mLOG_CAT_GBA_DEBUG, level, "%s", oolBuf);
548	}
549	gba->debugFlags = GBADebugFlagsClearSend(gba->debugFlags);
550}
551
552bool GBAIsROM(struct VFile* vf) {
553#ifdef USE_ELF
554	struct ELF* elf = ELFOpen(vf);
555	if (elf) {
556		uint32_t entry = ELFEntry(elf);
557		bool isGBA = true;
558		isGBA = isGBA && ELFMachine(elf) == EM_ARM;
559		isGBA = isGBA && (entry == BASE_CART0 || entry == BASE_WORKING_RAM);
560		ELFClose(elf);
561		return isGBA;
562	}
563#endif
564	if (!vf) {
565		return false;
566	}
567
568	uint8_t signature[sizeof(GBA_ROM_MAGIC) + sizeof(GBA_ROM_MAGIC2)];
569	if (vf->seek(vf, GBA_ROM_MAGIC_OFFSET, SEEK_SET) < 0) {
570		return false;
571	}
572	if (vf->read(vf, &signature, sizeof(GBA_ROM_MAGIC)) != sizeof(GBA_ROM_MAGIC)) {
573		return false;
574	}
575	if (memcmp(signature, GBA_ROM_MAGIC, sizeof(GBA_ROM_MAGIC)) != 0) {
576		return false;
577	}
578
579	if (vf->seek(vf, GBA_ROM_MAGIC_OFFSET2, SEEK_SET) < 0) {
580		return false;
581	}
582	if (vf->read(vf, &signature, sizeof(GBA_ROM_MAGIC2)) != sizeof(GBA_ROM_MAGIC2)) {
583		return false;
584	}
585	if (memcmp(signature, GBA_ROM_MAGIC2, sizeof(GBA_ROM_MAGIC2)) != 0) {
586		// If the signature byte is missing then we must be using an unfixed ROM
587		uint32_t buffer[0x9C / sizeof(uint32_t)];
588		if (vf->seek(vf, 0x4, SEEK_SET) < 0) {
589			return false;
590		}
591		if (vf->read(vf, &buffer, sizeof(buffer)) != sizeof(buffer)) {
592			return false;
593		}
594		uint32_t bits = 0;
595		size_t i;
596		for (i = 0; i < sizeof(buffer) / sizeof(*buffer); ++i) {
597			bits |= buffer[i];
598		}
599		if (bits) {
600			return false;
601		}
602	}
603
604
605	if (GBAIsBIOS(vf)) {
606		return false;
607	}
608	return true;
609}
610
611bool GBAIsMB(struct VFile* vf) {
612	if (!GBAIsROM(vf)) {
613		return false;
614	}
615#ifdef USE_ELF
616	struct ELF* elf = ELFOpen(vf);
617	if (elf) {
618		bool isMB = ELFEntry(elf) == BASE_WORKING_RAM;
619		ELFClose(elf);
620		return isMB;
621	}
622#endif
623	if (vf->size(vf) > SIZE_WORKING_RAM) {
624		return false;
625	}
626	if (vf->seek(vf, GBA_MB_MAGIC_OFFSET, SEEK_SET) < 0) {
627		return false;
628	}
629	uint32_t signature;
630	if (vf->read(vf, &signature, sizeof(signature)) != sizeof(signature)) {
631		return false;
632	}
633	uint32_t opcode;
634	LOAD_32(opcode, 0, &signature);
635	struct ARMInstructionInfo info;
636	ARMDecodeARM(opcode, &info);
637	if (info.branchType == ARM_BRANCH) {
638		if (info.op1.immediate <= 0) {
639			return false;
640		} else if (info.op1.immediate == 28) {
641			// Ancient toolchain that is known to throw MB detection for a loop
642			return false;
643		} else if (info.op1.immediate != 24) {
644			return true;
645		}
646	}
647
648	uint32_t pc = GBA_MB_MAGIC_OFFSET;
649	int i;
650	for (i = 0; i < 80; ++i) {
651		if (vf->read(vf, &signature, sizeof(signature)) != sizeof(signature)) {
652			break;
653		}
654		pc += 4;
655		LOAD_32(opcode, 0, &signature);
656		ARMDecodeARM(opcode, &info);
657		if (info.mnemonic != ARM_MN_LDR) {
658			continue;
659		}
660		if ((info.operandFormat & ARM_OPERAND_MEMORY) && info.memory.baseReg == ARM_PC && info.memory.format & ARM_MEMORY_IMMEDIATE_OFFSET) {
661			uint32_t immediate = info.memory.offset.immediate;
662			if (info.memory.format & ARM_MEMORY_OFFSET_SUBTRACT) {
663				immediate = -immediate;
664			}
665			immediate += pc + 8;
666			if (vf->seek(vf, immediate, SEEK_SET) < 0) {
667				break;
668			}
669			if (vf->read(vf, &signature, sizeof(signature)) != sizeof(signature)) {
670				break;
671			}
672			LOAD_32(immediate, 0, &signature);
673			if (vf->seek(vf, pc, SEEK_SET) < 0) {
674				break;
675			}
676			if ((immediate & ~0x7FF) == BASE_WORKING_RAM) {
677				return true;
678			}
679		}
680	}
681	// Found a libgba-linked cart...these are a bit harder to detect.
682	return false;
683}
684
685bool GBAIsBIOS(struct VFile* vf) {
686	if (vf->seek(vf, 0, SEEK_SET) < 0) {
687		return false;
688	}
689	uint8_t interruptTable[7 * 4];
690	if (vf->read(vf, &interruptTable, sizeof(interruptTable)) != sizeof(interruptTable)) {
691		return false;
692	}
693	int i;
694	for (i = 0; i < 7; ++i) {
695		if (interruptTable[4 * i + 3] != 0xEA || interruptTable[4 * i + 2]) {
696			return false;
697		}
698	}
699	return true;
700}
701
702void GBAGetGameCode(const struct GBA* gba, char* out) {
703	memset(out, 0, 8);
704	if (!gba->memory.rom) {
705		return;
706	}
707
708	memcpy(out, "AGB-", 4);
709	memcpy(&out[4], &((struct GBACartridge*) gba->memory.rom)->id, 4);
710}
711
712void GBAGetGameTitle(const struct GBA* gba, char* out) {
713	if (gba->memory.rom) {
714		memcpy(out, &((struct GBACartridge*) gba->memory.rom)->title, 12);
715		return;
716	}
717	if (gba->isPristine && gba->memory.wram) {
718		memcpy(out, &((struct GBACartridge*) gba->memory.wram)->title, 12);
719		return;
720	}
721	strncpy(out, "(BIOS)", 12);
722}
723
724void GBAHitStub(struct ARMCore* cpu, uint32_t opcode) {
725	struct GBA* gba = (struct GBA*) cpu->master;
726	UNUSED(gba);
727#ifdef USE_DEBUGGERS
728	if (gba->debugger) {
729		struct mDebuggerEntryInfo info = {
730			.address = _ARMPCAddress(cpu),
731			.type.bp.opcode = opcode
732		};
733		mDebuggerEnter(gba->debugger->d.p, DEBUGGER_ENTER_ILLEGAL_OP, &info);
734	}
735#endif
736	// TODO: More sensible category?
737	mLOG(GBA, ERROR, "Stub opcode: %08x", opcode);
738}
739
740void GBAIllegal(struct ARMCore* cpu, uint32_t opcode) {
741	struct GBA* gba = (struct GBA*) cpu->master;
742	if (cpu->executionMode == MODE_THUMB && (opcode & 0xFFC0) == 0xE800) {
743		mLOG(GBA, INFO, "Hit Wii U VC opcode: %08x", opcode);
744		return;
745	}
746	if (!gba->yankedRomSize) {
747		// TODO: More sensible category?
748		mLOG(GBA, WARN, "Illegal opcode: %08x", opcode);
749	}
750#ifdef USE_DEBUGGERS
751	if (gba->debugger) {
752		struct mDebuggerEntryInfo info = {
753			.address = _ARMPCAddress(cpu),
754			.type.bp.opcode = opcode
755		};
756		mDebuggerEnter(gba->debugger->d.p, DEBUGGER_ENTER_ILLEGAL_OP, &info);
757	}
758#endif
759	ARMRaiseUndefined(cpu);
760}
761
762void GBABreakpoint(struct ARMCore* cpu, int immediate) {
763	struct GBA* gba = (struct GBA*) cpu->master;
764	if (immediate >= CPU_COMPONENT_MAX) {
765		return;
766	}
767	switch (immediate) {
768#ifdef USE_DEBUGGERS
769	case CPU_COMPONENT_DEBUGGER:
770		if (gba->debugger) {
771			struct mDebuggerEntryInfo info = {
772				.address = _ARMPCAddress(cpu),
773				.type.bp.breakType = BREAKPOINT_SOFTWARE,
774				.pointId = -1
775			};
776			mDebuggerEnter(gba->debugger->d.p, DEBUGGER_ENTER_BREAKPOINT, &info);
777		}
778		break;
779#endif
780	case CPU_COMPONENT_CHEAT_DEVICE:
781		if (gba->cpu->components[CPU_COMPONENT_CHEAT_DEVICE]) {
782			struct mCheatDevice* device = (struct mCheatDevice*) gba->cpu->components[CPU_COMPONENT_CHEAT_DEVICE];
783			struct GBACheatHook* hook = 0;
784			size_t i;
785			for (i = 0; i < mCheatSetsSize(&device->cheats); ++i) {
786				struct GBACheatSet* cheats = (struct GBACheatSet*) *mCheatSetsGetPointer(&device->cheats, i);
787				if (cheats->hook && cheats->hook->address == _ARMPCAddress(cpu)) {
788					mCheatRefresh(device, &cheats->d);
789					hook = cheats->hook;
790				}
791			}
792			if (hook) {
793				ARMRunFake(cpu, hook->patchedOpcode);
794			}
795		}
796		break;
797	default:
798		break;
799	}
800}
801
802void GBAFrameStarted(struct GBA* gba) {
803	GBATestKeypadIRQ(gba);
804
805	if (gba->audio.mixer) {
806		gba->audio.mixer->vblank(gba->audio.mixer);
807	}
808
809	size_t c;
810	for (c = 0; c < mCoreCallbacksListSize(&gba->coreCallbacks); ++c) {
811		struct mCoreCallbacks* callbacks = mCoreCallbacksListGetPointer(&gba->coreCallbacks, c);
812		if (callbacks->videoFrameStarted) {
813			callbacks->videoFrameStarted(callbacks->context);
814		}
815	}
816}
817
818void GBAFrameEnded(struct GBA* gba) {
819	GBASavedataClean(&gba->memory.savedata, gba->video.frameCounter);
820
821	if (gba->cpu->components && gba->cpu->components[CPU_COMPONENT_CHEAT_DEVICE]) {
822		struct mCheatDevice* device = (struct mCheatDevice*) gba->cpu->components[CPU_COMPONENT_CHEAT_DEVICE];
823		size_t i;
824		for (i = 0; i < mCheatSetsSize(&device->cheats); ++i) {
825			struct GBACheatSet* cheats = (struct GBACheatSet*) *mCheatSetsGetPointer(&device->cheats, i);
826			if (!cheats->hook) {
827				mCheatRefresh(device, &cheats->d);
828			}
829		}
830	}
831
832	if (gba->stream && gba->stream->postVideoFrame) {
833		const color_t* pixels;
834		size_t stride;
835		gba->video.renderer->getPixels(gba->video.renderer, &stride, (const void**) &pixels);
836		gba->stream->postVideoFrame(gba->stream, pixels, stride);
837	}
838
839	if (gba->memory.hw.devices & (HW_GB_PLAYER | HW_GB_PLAYER_DETECTION)) {
840		GBAHardwarePlayerUpdate(gba);
841	}
842
843	size_t c;
844	for (c = 0; c < mCoreCallbacksListSize(&gba->coreCallbacks); ++c) {
845		struct mCoreCallbacks* callbacks = mCoreCallbacksListGetPointer(&gba->coreCallbacks, c);
846		if (callbacks->videoFrameEnded) {
847			callbacks->videoFrameEnded(callbacks->context);
848		}
849	}
850}
851
852void GBATestKeypadIRQ(struct GBA* gba) {
853	uint16_t keycnt = gba->memory.io[REG_KEYCNT >> 1];
854	if (!(keycnt & 0x4000)) {
855		return;
856	}
857	int isAnd = keycnt & 0x8000;
858	if (!gba->keySource) {
859		// TODO?
860		return;
861	}
862
863	keycnt &= 0x3FF;
864	uint16_t keyInput = *gba->keySource & keycnt;
865
866	if (isAnd && keycnt == keyInput) {
867		GBARaiseIRQ(gba, IRQ_KEYPAD, 0);
868	} else if (!isAnd && keyInput) {
869		GBARaiseIRQ(gba, IRQ_KEYPAD, 0);
870	}
871}
872
873static void _triggerIRQ(struct mTiming* timing, void* user, uint32_t cyclesLate) {
874	UNUSED(timing);
875	UNUSED(cyclesLate);
876	struct GBA* gba = user;
877	gba->cpu->halted = 0;
878	if (!(gba->memory.io[REG_IE >> 1] & gba->memory.io[REG_IF >> 1])) {
879		return;
880	}
881
882	if (gba->memory.io[REG_IME >> 1] && !gba->cpu->cpsr.i) {
883		ARMRaiseIRQ(gba->cpu);
884	}
885}
886
887void GBASetBreakpoint(struct GBA* gba, struct mCPUComponent* component, uint32_t address, enum ExecutionMode mode, uint32_t* opcode) {
888	size_t immediate;
889	for (immediate = 0; immediate < gba->cpu->numComponents; ++immediate) {
890		if (gba->cpu->components[immediate] == component) {
891			break;
892		}
893	}
894	if (immediate == gba->cpu->numComponents) {
895		return;
896	}
897	if (mode == MODE_ARM) {
898		int32_t value;
899		int32_t old;
900		value = 0xE1200070;
901		value |= immediate & 0xF;
902		value |= (immediate & 0xFFF0) << 4;
903		GBAPatch32(gba->cpu, address, value, &old);
904		*opcode = old;
905	} else {
906		int16_t value;
907		int16_t old;
908		value = 0xBE00;
909		value |= immediate & 0xFF;
910		GBAPatch16(gba->cpu, address, value, &old);
911		*opcode = (uint16_t) old;
912	}
913}
914
915void GBAClearBreakpoint(struct GBA* gba, uint32_t address, enum ExecutionMode mode, uint32_t opcode) {
916	if (mode == MODE_ARM) {
917		GBAPatch32(gba->cpu, address, opcode, 0);
918	} else {
919		GBAPatch16(gba->cpu, address, opcode, 0);
920	}
921}
922
923#ifdef USE_DEBUGGERS
924static bool _setSoftwareBreakpoint(struct ARMDebugger* debugger, uint32_t address, enum ExecutionMode mode, uint32_t* opcode) {
925	GBASetBreakpoint((struct GBA*) debugger->cpu->master, &debugger->d.p->d, address, mode, opcode);
926	return true;
927}
928
929static void _clearSoftwareBreakpoint(struct ARMDebugger* debugger, const struct ARMDebugBreakpoint* breakpoint) {
930	GBAClearBreakpoint((struct GBA*) debugger->cpu->master, breakpoint->d.address, breakpoint->sw.mode, breakpoint->sw.opcode);
931}
932#endif