all repos — mgba @ 4ca16fb2ef9288d64f9c895888e28dd94e7e1a36

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;
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	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	gba->memory.bios = bios;
454	gba->memory.fullBios = 1;
455	uint32_t checksum = GBAChecksum(gba->memory.bios, SIZE_BIOS);
456	mLOG(GBA, DEBUG, "BIOS Checksum: 0x%X", checksum);
457	if (checksum == GBA_BIOS_CHECKSUM) {
458		mLOG(GBA, INFO, "Official GBA BIOS detected");
459	} else if (checksum == GBA_DS_BIOS_CHECKSUM) {
460		mLOG(GBA, INFO, "Official GBA (DS) BIOS detected");
461	} else {
462		mLOG(GBA, WARN, "BIOS checksum incorrect");
463	}
464	gba->biosChecksum = checksum;
465	if (gba->memory.activeRegion == REGION_BIOS) {
466		gba->cpu->memory.activeRegion = gba->memory.bios;
467	}
468	// TODO: error check
469}
470
471void GBAApplyPatch(struct GBA* gba, struct Patch* patch) {
472	size_t patchedSize = patch->outputSize(patch, gba->memory.romSize);
473	if (!patchedSize || patchedSize > SIZE_CART0) {
474		return;
475	}
476	void* newRom = anonymousMemoryMap(SIZE_CART0);
477	if (!patch->applyPatch(patch, gba->memory.rom, gba->pristineRomSize, newRom, patchedSize)) {
478		mappedMemoryFree(newRom, SIZE_CART0);
479		return;
480	}
481	if (gba->romVf) {
482#ifndef FIXED_ROM_BUFFER
483		gba->romVf->unmap(gba->romVf, gba->memory.rom, gba->pristineRomSize);
484#endif
485		gba->romVf->close(gba->romVf);
486		gba->romVf = NULL;
487	}
488	gba->isPristine = false;
489	gba->memory.rom = newRom;
490	gba->memory.hw.gpioBase = &((uint16_t*) gba->memory.rom)[GPIO_REG_DATA >> 1];
491	gba->memory.romSize = patchedSize;
492	gba->memory.romMask = SIZE_CART0 - 1;
493	gba->romCrc32 = doCrc32(gba->memory.rom, gba->memory.romSize);
494}
495
496void GBARaiseIRQ(struct GBA* gba, enum GBAIRQ irq, uint32_t cyclesLate) {
497	gba->memory.io[REG_IF >> 1] |= 1 << irq;
498	GBATestIRQ(gba, cyclesLate);
499}
500
501void GBATestIRQNoDelay(struct ARMCore* cpu) {
502	struct GBA* gba = (struct GBA*) cpu->master;
503	GBATestIRQ(gba, 0);
504}
505
506void GBATestIRQ(struct GBA* gba, uint32_t cyclesLate) {
507	if (gba->memory.io[REG_IE >> 1] & gba->memory.io[REG_IF >> 1]) {
508		if (!mTimingIsScheduled(&gba->timing, &gba->irqEvent)) {
509			mTimingSchedule(&gba->timing, &gba->irqEvent, GBA_IRQ_DELAY - cyclesLate);
510		}
511	}
512}
513
514void GBAHalt(struct GBA* gba) {
515	gba->cpu->nextEvent = gba->cpu->cycles;
516	gba->cpu->halted = 1;
517}
518
519void GBAStop(struct GBA* gba) {
520	size_t c;
521	for (c = 0; c < mCoreCallbacksListSize(&gba->coreCallbacks); ++c) {
522		struct mCoreCallbacks* callbacks = mCoreCallbacksListGetPointer(&gba->coreCallbacks, c);
523		if (callbacks->sleep) {
524			callbacks->sleep(callbacks->context);
525		}
526	}
527	gba->cpu->nextEvent = gba->cpu->cycles;
528}
529
530void GBADebug(struct GBA* gba, uint16_t flags) {
531	gba->debugFlags = flags;
532	if (GBADebugFlagsIsSend(gba->debugFlags)) {
533		int level = 1 << GBADebugFlagsGetLevel(gba->debugFlags);
534		level &= 0x1F;
535		char oolBuf[0x101];
536		strncpy(oolBuf, gba->debugString, sizeof(oolBuf) - 1);
537		memset(gba->debugString, 0, sizeof(gba->debugString));
538		oolBuf[0x100] = '\0';
539		mLog(_mLOG_CAT_GBA_DEBUG, level, "%s", oolBuf);
540	}
541	gba->debugFlags = GBADebugFlagsClearSend(gba->debugFlags);
542}
543
544bool GBAIsROM(struct VFile* vf) {
545#ifdef USE_ELF
546	struct ELF* elf = ELFOpen(vf);
547	if (elf) {
548		uint32_t entry = ELFEntry(elf);
549		bool isGBA = true;
550		isGBA = isGBA && ELFMachine(elf) == EM_ARM;
551		isGBA = isGBA && (entry == BASE_CART0 || entry == BASE_WORKING_RAM);
552		ELFClose(elf);
553		return isGBA;
554	}
555#endif
556	if (!vf) {
557		return false;
558	}
559
560	uint8_t signature[sizeof(GBA_ROM_MAGIC) + sizeof(GBA_ROM_MAGIC2)];
561	if (vf->seek(vf, GBA_ROM_MAGIC_OFFSET, SEEK_SET) < 0) {
562		return false;
563	}
564	if (vf->read(vf, &signature, sizeof(GBA_ROM_MAGIC)) != sizeof(GBA_ROM_MAGIC)) {
565		return false;
566	}
567	if (memcmp(signature, GBA_ROM_MAGIC, sizeof(GBA_ROM_MAGIC)) != 0) {
568		return false;
569	}
570
571	if (vf->seek(vf, GBA_ROM_MAGIC_OFFSET2, SEEK_SET) < 0) {
572		return false;
573	}
574	if (vf->read(vf, &signature, sizeof(GBA_ROM_MAGIC2)) != sizeof(GBA_ROM_MAGIC2)) {
575		return false;
576	}
577	if (memcmp(signature, GBA_ROM_MAGIC2, sizeof(GBA_ROM_MAGIC2)) != 0) {
578		// If the signature byte is missing then we must be using an unfixed ROM
579		uint32_t buffer[0x9C / sizeof(uint32_t)];
580		if (vf->seek(vf, 0x4, SEEK_SET) < 0) {
581			return false;
582		}
583		if (vf->read(vf, &buffer, sizeof(buffer)) != sizeof(buffer)) {
584			return false;
585		}
586		uint32_t bits = 0;
587		size_t i;
588		for (i = 0; i < sizeof(buffer) / sizeof(*buffer); ++i) {
589			bits |= buffer[i];
590		}
591		if (bits) {
592			return false;
593		}
594	}
595
596
597	if (GBAIsBIOS(vf)) {
598		return false;
599	}
600	return true;
601}
602
603bool GBAIsMB(struct VFile* vf) {
604	if (!GBAIsROM(vf)) {
605		return false;
606	}
607#ifdef USE_ELF
608	struct ELF* elf = ELFOpen(vf);
609	if (elf) {
610		bool isMB = ELFEntry(elf) == BASE_WORKING_RAM;
611		ELFClose(elf);
612		return isMB;
613	}
614#endif
615	if (vf->size(vf) > SIZE_WORKING_RAM) {
616		return false;
617	}
618	if (vf->seek(vf, GBA_MB_MAGIC_OFFSET, SEEK_SET) < 0) {
619		return false;
620	}
621	uint32_t signature;
622	if (vf->read(vf, &signature, sizeof(signature)) != sizeof(signature)) {
623		return false;
624	}
625	uint32_t opcode;
626	LOAD_32(opcode, 0, &signature);
627	struct ARMInstructionInfo info;
628	ARMDecodeARM(opcode, &info);
629	if (info.branchType == ARM_BRANCH) {
630		if (info.op1.immediate <= 0) {
631			return false;
632		} else if (info.op1.immediate == 28) {
633			// Ancient toolchain that is known to throw MB detection for a loop
634			return false;
635		} else if (info.op1.immediate != 24) {
636			return true;
637		}
638	}
639
640	uint32_t pc = GBA_MB_MAGIC_OFFSET;
641	int i;
642	for (i = 0; i < 80; ++i) {
643		if (vf->read(vf, &signature, sizeof(signature)) != sizeof(signature)) {
644			break;
645		}
646		pc += 4;
647		LOAD_32(opcode, 0, &signature);
648		ARMDecodeARM(opcode, &info);
649		if (info.mnemonic != ARM_MN_LDR) {
650			continue;
651		}
652		if ((info.operandFormat & ARM_OPERAND_MEMORY) && info.memory.baseReg == ARM_PC && info.memory.format & ARM_MEMORY_IMMEDIATE_OFFSET) {
653			uint32_t immediate = info.memory.offset.immediate;
654			if (info.memory.format & ARM_MEMORY_OFFSET_SUBTRACT) {
655				immediate = -immediate;
656			}
657			immediate += pc + 8;
658			if (vf->seek(vf, immediate, SEEK_SET) < 0) {
659				break;
660			}
661			if (vf->read(vf, &signature, sizeof(signature)) != sizeof(signature)) {
662				break;
663			}
664			LOAD_32(immediate, 0, &signature);
665			if (vf->seek(vf, pc, SEEK_SET) < 0) {
666				break;
667			}
668			if ((immediate & ~0x7FF) == BASE_WORKING_RAM) {
669				return true;
670			}
671		}
672	}
673	// Found a libgba-linked cart...these are a bit harder to detect.
674	return false;
675}
676
677bool GBAIsBIOS(struct VFile* vf) {
678	if (vf->seek(vf, 0, SEEK_SET) < 0) {
679		return false;
680	}
681	uint8_t interruptTable[7 * 4];
682	if (vf->read(vf, &interruptTable, sizeof(interruptTable)) != sizeof(interruptTable)) {
683		return false;
684	}
685	int i;
686	for (i = 0; i < 7; ++i) {
687		if (interruptTable[4 * i + 3] != 0xEA || interruptTable[4 * i + 2]) {
688			return false;
689		}
690	}
691	return true;
692}
693
694void GBAGetGameCode(const struct GBA* gba, char* out) {
695	memset(out, 0, 8);
696	if (!gba->memory.rom) {
697		return;
698	}
699
700	memcpy(out, "AGB-", 4);
701	memcpy(&out[4], &((struct GBACartridge*) gba->memory.rom)->id, 4);
702}
703
704void GBAGetGameTitle(const struct GBA* gba, char* out) {
705	if (gba->memory.rom) {
706		memcpy(out, &((struct GBACartridge*) gba->memory.rom)->title, 12);
707		return;
708	}
709	if (gba->isPristine && gba->memory.wram) {
710		memcpy(out, &((struct GBACartridge*) gba->memory.wram)->title, 12);
711		return;
712	}
713	strncpy(out, "(BIOS)", 12);
714}
715
716void GBAHitStub(struct ARMCore* cpu, uint32_t opcode) {
717	struct GBA* gba = (struct GBA*) cpu->master;
718	UNUSED(gba);
719#ifdef USE_DEBUGGERS
720	if (gba->debugger) {
721		struct mDebuggerEntryInfo info = {
722			.address = _ARMPCAddress(cpu),
723			.type.bp.opcode = opcode
724		};
725		mDebuggerEnter(gba->debugger->d.p, DEBUGGER_ENTER_ILLEGAL_OP, &info);
726	}
727#endif
728	// TODO: More sensible category?
729	mLOG(GBA, ERROR, "Stub opcode: %08x", opcode);
730}
731
732void GBAIllegal(struct ARMCore* cpu, uint32_t opcode) {
733	struct GBA* gba = (struct GBA*) cpu->master;
734	if (!gba->yankedRomSize) {
735		// TODO: More sensible category?
736		mLOG(GBA, WARN, "Illegal opcode: %08x", opcode);
737	}
738	if (cpu->executionMode == MODE_THUMB && (opcode & 0xFFC0) == 0xE800) {
739		mLOG(GBA, DEBUG, "Hit Wii U VC opcode: %08x", opcode);
740		return;
741	}
742#ifdef USE_DEBUGGERS
743	if (gba->debugger) {
744		struct mDebuggerEntryInfo info = {
745			.address = _ARMPCAddress(cpu),
746			.type.bp.opcode = opcode
747		};
748		mDebuggerEnter(gba->debugger->d.p, DEBUGGER_ENTER_ILLEGAL_OP, &info);
749	} else
750#endif
751	{
752		ARMRaiseUndefined(cpu);
753	}
754}
755
756void GBABreakpoint(struct ARMCore* cpu, int immediate) {
757	struct GBA* gba = (struct GBA*) cpu->master;
758	if (immediate >= CPU_COMPONENT_MAX) {
759		return;
760	}
761	switch (immediate) {
762#ifdef USE_DEBUGGERS
763	case CPU_COMPONENT_DEBUGGER:
764		if (gba->debugger) {
765			struct mDebuggerEntryInfo info = {
766				.address = _ARMPCAddress(cpu),
767				.type.bp.breakType = BREAKPOINT_SOFTWARE,
768				.pointId = -1
769			};
770			mDebuggerEnter(gba->debugger->d.p, DEBUGGER_ENTER_BREAKPOINT, &info);
771		}
772		break;
773#endif
774	case CPU_COMPONENT_CHEAT_DEVICE:
775		if (gba->cpu->components[CPU_COMPONENT_CHEAT_DEVICE]) {
776			struct mCheatDevice* device = (struct mCheatDevice*) gba->cpu->components[CPU_COMPONENT_CHEAT_DEVICE];
777			struct GBACheatHook* hook = 0;
778			size_t i;
779			for (i = 0; i < mCheatSetsSize(&device->cheats); ++i) {
780				struct GBACheatSet* cheats = (struct GBACheatSet*) *mCheatSetsGetPointer(&device->cheats, i);
781				if (cheats->hook && cheats->hook->address == _ARMPCAddress(cpu)) {
782					mCheatRefresh(device, &cheats->d);
783					hook = cheats->hook;
784				}
785			}
786			if (hook) {
787				ARMRunFake(cpu, hook->patchedOpcode);
788			}
789		}
790		break;
791	default:
792		break;
793	}
794}
795
796void GBAFrameStarted(struct GBA* gba) {
797	GBATestKeypadIRQ(gba);
798
799	if (gba->audio.mixer) {
800		gba->audio.mixer->vblank(gba->audio.mixer);
801	}
802
803	size_t c;
804	for (c = 0; c < mCoreCallbacksListSize(&gba->coreCallbacks); ++c) {
805		struct mCoreCallbacks* callbacks = mCoreCallbacksListGetPointer(&gba->coreCallbacks, c);
806		if (callbacks->videoFrameStarted) {
807			callbacks->videoFrameStarted(callbacks->context);
808		}
809	}
810}
811
812void GBAFrameEnded(struct GBA* gba) {
813	GBASavedataClean(&gba->memory.savedata, gba->video.frameCounter);
814
815	if (gba->rr) {
816		gba->rr->nextFrame(gba->rr);
817	}
818
819	if (gba->cpu->components && gba->cpu->components[CPU_COMPONENT_CHEAT_DEVICE]) {
820		struct mCheatDevice* device = (struct mCheatDevice*) gba->cpu->components[CPU_COMPONENT_CHEAT_DEVICE];
821		size_t i;
822		for (i = 0; i < mCheatSetsSize(&device->cheats); ++i) {
823			struct GBACheatSet* cheats = (struct GBACheatSet*) *mCheatSetsGetPointer(&device->cheats, i);
824			if (!cheats->hook) {
825				mCheatRefresh(device, &cheats->d);
826			}
827		}
828	}
829
830	if (gba->stream && gba->stream->postVideoFrame) {
831		const color_t* pixels;
832		size_t stride;
833		gba->video.renderer->getPixels(gba->video.renderer, &stride, (const void**) &pixels);
834		gba->stream->postVideoFrame(gba->stream, pixels, stride);
835	}
836
837	if (gba->memory.hw.devices & (HW_GB_PLAYER | HW_GB_PLAYER_DETECTION)) {
838		GBAHardwarePlayerUpdate(gba);
839	}
840
841	size_t c;
842	for (c = 0; c < mCoreCallbacksListSize(&gba->coreCallbacks); ++c) {
843		struct mCoreCallbacks* callbacks = mCoreCallbacksListGetPointer(&gba->coreCallbacks, c);
844		if (callbacks->videoFrameEnded) {
845			callbacks->videoFrameEnded(callbacks->context);
846		}
847	}
848}
849
850void GBATestKeypadIRQ(struct GBA* gba) {
851	uint16_t keycnt = gba->memory.io[REG_KEYCNT >> 1];
852	if (!(keycnt & 0x4000)) {
853		return;
854	}
855	int isAnd = keycnt & 0x8000;
856	if (!gba->keySource) {
857		// TODO?
858		return;
859	}
860
861	keycnt &= 0x3FF;
862	uint16_t keyInput = *gba->keySource & keycnt;
863
864	if (isAnd && keycnt == keyInput) {
865		GBARaiseIRQ(gba, IRQ_KEYPAD, 0);
866	} else if (!isAnd && keyInput) {
867		GBARaiseIRQ(gba, IRQ_KEYPAD, 0);
868	}
869}
870
871static void _triggerIRQ(struct mTiming* timing, void* user, uint32_t cyclesLate) {
872	UNUSED(timing);
873	UNUSED(cyclesLate);
874	struct GBA* gba = user;
875	gba->cpu->halted = 0;
876	if (!(gba->memory.io[REG_IE >> 1] & gba->memory.io[REG_IF >> 1])) {
877		return;
878	}
879
880	if (gba->memory.io[REG_IME >> 1] && !gba->cpu->cpsr.i) {
881		ARMRaiseIRQ(gba->cpu);
882	}
883}
884
885void GBASetBreakpoint(struct GBA* gba, struct mCPUComponent* component, uint32_t address, enum ExecutionMode mode, uint32_t* opcode) {
886	size_t immediate;
887	for (immediate = 0; immediate < gba->cpu->numComponents; ++immediate) {
888		if (gba->cpu->components[immediate] == component) {
889			break;
890		}
891	}
892	if (immediate == gba->cpu->numComponents) {
893		return;
894	}
895	if (mode == MODE_ARM) {
896		int32_t value;
897		int32_t old;
898		value = 0xE1200070;
899		value |= immediate & 0xF;
900		value |= (immediate & 0xFFF0) << 4;
901		GBAPatch32(gba->cpu, address, value, &old);
902		*opcode = old;
903	} else {
904		int16_t value;
905		int16_t old;
906		value = 0xBE00;
907		value |= immediate & 0xFF;
908		GBAPatch16(gba->cpu, address, value, &old);
909		*opcode = (uint16_t) old;
910	}
911}
912
913void GBAClearBreakpoint(struct GBA* gba, uint32_t address, enum ExecutionMode mode, uint32_t opcode) {
914	if (mode == MODE_ARM) {
915		GBAPatch32(gba->cpu, address, opcode, 0);
916	} else {
917		GBAPatch16(gba->cpu, address, opcode, 0);
918	}
919}
920
921#ifdef USE_DEBUGGERS
922static bool _setSoftwareBreakpoint(struct ARMDebugger* debugger, uint32_t address, enum ExecutionMode mode, uint32_t* opcode) {
923	GBASetBreakpoint((struct GBA*) debugger->cpu->master, &debugger->d.p->d, address, mode, opcode);
924	return true;
925}
926
927static bool _clearSoftwareBreakpoint(struct ARMDebugger* debugger, uint32_t address, enum ExecutionMode mode, uint32_t opcode) {
928	GBAClearBreakpoint((struct GBA*) debugger->cpu->master, address, mode, opcode);
929	return true;
930}
931#endif