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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#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
 28mLOG_DEFINE_CATEGORY(GBA, "GBA", "gba");
 29mLOG_DEFINE_CATEGORY(GBA_DEBUG, "GBA Debug", "gba.debug");
 30
 31const uint32_t GBA_COMPONENT_MAGIC = 0x1000000;
 32
 33static const size_t GBA_ROM_MAGIC_OFFSET = 3;
 34static const uint8_t GBA_ROM_MAGIC[] = { 0xEA };
 35
 36static const size_t GBA_MB_MAGIC_OFFSET = 0xC0;
 37
 38static void GBAInit(void* cpu, struct mCPUComponent* component);
 39static void GBAInterruptHandlerInit(struct ARMInterruptHandler* irqh);
 40static void GBAProcessEvents(struct ARMCore* cpu);
 41static void GBAHitStub(struct ARMCore* cpu, uint32_t opcode);
 42static void GBAIllegal(struct ARMCore* cpu, uint32_t opcode);
 43static void GBABreakpoint(struct ARMCore* cpu, int immediate);
 44
 45static bool _setSoftwareBreakpoint(struct ARMDebugger*, uint32_t address, enum ExecutionMode mode, uint32_t* opcode);
 46static bool _clearSoftwareBreakpoint(struct ARMDebugger*, uint32_t address, enum ExecutionMode mode, uint32_t opcode);
 47
 48
 49#ifdef FIXED_ROM_BUFFER
 50extern uint32_t* romBuffer;
 51extern size_t romBufferSize;
 52#endif
 53
 54void GBACreate(struct GBA* gba) {
 55	gba->d.id = GBA_COMPONENT_MAGIC;
 56	gba->d.init = GBAInit;
 57	gba->d.deinit = 0;
 58}
 59
 60static void GBAInit(void* cpu, struct mCPUComponent* component) {
 61	struct GBA* gba = (struct GBA*) component;
 62	gba->cpu = cpu;
 63	gba->debugger = 0;
 64	gba->sync = 0;
 65
 66	GBAInterruptHandlerInit(&gba->cpu->irqh);
 67	GBAMemoryInit(gba);
 68
 69	gba->memory.savedata.timing = &gba->timing;
 70	GBASavedataInit(&gba->memory.savedata, NULL);
 71
 72	gba->video.p = gba;
 73	GBAVideoInit(&gba->video);
 74
 75	gba->audio.p = gba;
 76	GBAAudioInit(&gba->audio, GBA_AUDIO_SAMPLES);
 77
 78	GBAIOInit(gba);
 79
 80	gba->sio.p = gba;
 81	GBASIOInit(&gba->sio);
 82
 83	GBAHardwareInit(&gba->memory.hw, NULL);
 84
 85	gba->springIRQ = 0;
 86	gba->keySource = 0;
 87	gba->rotationSource = 0;
 88	gba->luminanceSource = 0;
 89	gba->rtcSource = 0;
 90	gba->rumble = 0;
 91	gba->rr = 0;
 92
 93	gba->romVf = 0;
 94	gba->biosVf = 0;
 95
 96	gba->stream = NULL;
 97	gba->keyCallback = NULL;
 98	mCoreCallbacksListInit(&gba->coreCallbacks, 0);
 99
100	gba->biosChecksum = GBAChecksum(gba->memory.bios, SIZE_BIOS);
101
102	gba->idleOptimization = IDLE_LOOP_REMOVE;
103	gba->idleLoop = IDLE_LOOP_NONE;
104
105	gba->realisticTiming = true;
106	gba->hardCrash = true;
107	gba->allowOpposingDirections = true;
108
109	gba->performingDMA = false;
110
111	gba->isPristine = false;
112	gba->pristineRomSize = 0;
113	gba->yankedRomSize = 0;
114
115	mTimingInit(&gba->timing, &gba->cpu->cycles, &gba->cpu->nextEvent);
116}
117
118void GBAUnloadROM(struct GBA* gba) {
119	if (gba->memory.rom && !gba->isPristine) {
120		if (gba->yankedRomSize) {
121			gba->yankedRomSize = 0;
122		}
123		mappedMemoryFree(gba->memory.rom, SIZE_CART0);
124	}
125
126	if (gba->romVf) {
127#ifndef FIXED_ROM_BUFFER
128		gba->romVf->unmap(gba->romVf, gba->memory.rom, gba->pristineRomSize);
129#endif
130		gba->romVf->close(gba->romVf);
131		gba->romVf = NULL;
132	}
133	gba->memory.rom = NULL;
134	gba->isPristine = false;
135
136	GBASavedataDeinit(&gba->memory.savedata);
137	if (gba->memory.savedata.realVf) {
138		gba->memory.savedata.realVf->close(gba->memory.savedata.realVf);
139		gba->memory.savedata.realVf = 0;
140	}
141	gba->idleLoop = IDLE_LOOP_NONE;
142}
143
144void GBADestroy(struct GBA* gba) {
145	GBAUnloadROM(gba);
146
147	if (gba->biosVf) {
148		gba->biosVf->unmap(gba->biosVf, gba->memory.bios, SIZE_BIOS);
149		gba->biosVf->close(gba->biosVf);
150		gba->biosVf = 0;
151	}
152
153	GBAMemoryDeinit(gba);
154	GBAVideoDeinit(&gba->video);
155	GBAAudioDeinit(&gba->audio);
156	GBASIODeinit(&gba->sio);
157	gba->rr = 0;
158	mTimingDeinit(&gba->timing);
159	mCoreCallbacksListDeinit(&gba->coreCallbacks);
160}
161
162void GBAInterruptHandlerInit(struct ARMInterruptHandler* irqh) {
163	irqh->reset = GBAReset;
164	irqh->processEvents = GBAProcessEvents;
165	irqh->swi16 = GBASwi16;
166	irqh->swi32 = GBASwi32;
167	irqh->hitIllegal = GBAIllegal;
168	irqh->readCPSR = GBATestIRQ;
169	irqh->hitStub = GBAHitStub;
170	irqh->bkpt16 = GBABreakpoint;
171	irqh->bkpt32 = GBABreakpoint;
172}
173
174void GBAReset(struct ARMCore* cpu) {
175	ARMSetPrivilegeMode(cpu, MODE_IRQ);
176	cpu->gprs[ARM_SP] = SP_BASE_IRQ;
177	ARMSetPrivilegeMode(cpu, MODE_SUPERVISOR);
178	cpu->gprs[ARM_SP] = SP_BASE_SUPERVISOR;
179	ARMSetPrivilegeMode(cpu, MODE_SYSTEM);
180	cpu->gprs[ARM_SP] = SP_BASE_SYSTEM;
181
182	struct GBA* gba = (struct GBA*) cpu->master;
183	if (!gba->rr || (!gba->rr->isPlaying(gba->rr) && !gba->rr->isRecording(gba->rr))) {
184		GBASavedataUnmask(&gba->memory.savedata);
185	}
186
187	gba->cpuBlocked = false;
188	gba->earlyExit = false;
189	if (gba->yankedRomSize) {
190		gba->memory.romSize = gba->yankedRomSize;
191		gba->memory.romMask = toPow2(gba->memory.romSize) - 1;
192		gba->yankedRomSize = 0;
193	}
194	mTimingClear(&gba->timing);
195	GBAMemoryReset(gba);
196	GBAVideoReset(&gba->video);
197	GBAAudioReset(&gba->audio);
198	GBAIOInit(gba);
199	GBATimerInit(gba);
200
201	GBASIOReset(&gba->sio);
202
203	gba->lastJump = 0;
204	gba->haltPending = false;
205	gba->idleDetectionStep = 0;
206	gba->idleDetectionFailures = 0;
207
208	gba->debug = false;
209	memset(gba->debugString, 0, sizeof(gba->debugString));
210
211	if (!gba->romVf && gba->memory.rom) {
212		GBASkipBIOS(gba);
213	}
214}
215
216void GBASkipBIOS(struct GBA* gba) {
217	struct ARMCore* cpu = gba->cpu;
218	if (cpu->gprs[ARM_PC] == BASE_RESET + WORD_SIZE_ARM) {
219		if (gba->memory.rom) {
220			cpu->gprs[ARM_PC] = BASE_CART0;
221		} else {
222			cpu->gprs[ARM_PC] = BASE_WORKING_RAM;
223		}
224		gba->memory.io[REG_VCOUNT >> 1] = 0x7E;
225		gba->memory.io[REG_POSTFLG >> 1] = 1;
226		int currentCycles = 0;
227		ARM_WRITE_PC;
228	}
229}
230
231static void GBAProcessEvents(struct ARMCore* cpu) {
232	struct GBA* gba = (struct GBA*) cpu->master;
233
234	gba->bus = cpu->prefetch[1];
235	if (cpu->executionMode == MODE_THUMB) {
236		gba->bus |= cpu->prefetch[1] << 16;
237	}
238
239	if (gba->springIRQ && !cpu->cpsr.i) {
240		ARMRaiseIRQ(cpu);
241		gba->springIRQ = 0;
242	}
243
244	int32_t nextEvent = cpu->nextEvent;
245	while (cpu->cycles >= nextEvent) {
246		int32_t cycles = cpu->cycles;
247
248		cpu->cycles = 0;
249		cpu->nextEvent = INT_MAX;
250
251#ifndef NDEBUG
252		if (cycles < 0) {
253			mLOG(GBA, FATAL, "Negative cycles passed: %i", cycles);
254		}
255#endif
256		nextEvent = cycles;
257		do {
258			nextEvent = mTimingTick(&gba->timing, nextEvent);
259		} while (gba->cpuBlocked);
260
261		cpu->nextEvent = nextEvent;
262
263		if (gba->earlyExit) {
264			gba->earlyExit = false;
265			break;
266		}
267		if (cpu->halted) {
268			cpu->cycles = nextEvent;
269			if (!gba->memory.io[REG_IME >> 1] || !gba->memory.io[REG_IE >> 1]) {
270				break;
271			}
272		}
273#ifndef NDEBUG
274		else if (nextEvent < 0) {
275			mLOG(GBA, FATAL, "Negative cycles will pass: %i", nextEvent);
276		}
277#endif
278	}
279}
280
281#ifdef USE_DEBUGGERS
282void GBAAttachDebugger(struct GBA* gba, struct mDebugger* debugger) {
283	gba->debugger = (struct ARMDebugger*) debugger->platform;
284	gba->debugger->setSoftwareBreakpoint = _setSoftwareBreakpoint;
285	gba->debugger->clearSoftwareBreakpoint = _clearSoftwareBreakpoint;
286	gba->cpu->components[CPU_COMPONENT_DEBUGGER] = &debugger->d;
287	ARMHotplugAttach(gba->cpu, CPU_COMPONENT_DEBUGGER);
288}
289
290void GBADetachDebugger(struct GBA* gba) {
291	if (gba->debugger) {
292		ARMHotplugDetach(gba->cpu, CPU_COMPONENT_DEBUGGER);
293	}
294	gba->cpu->components[CPU_COMPONENT_DEBUGGER] = NULL;
295	gba->debugger = NULL;
296}
297#endif
298
299bool GBALoadNull(struct GBA* gba) {
300	GBAUnloadROM(gba);
301	gba->romVf = NULL;
302	gba->pristineRomSize = 0;
303	gba->memory.wram = anonymousMemoryMap(SIZE_WORKING_RAM);
304#ifndef FIXED_ROM_BUFFER
305	gba->memory.rom = anonymousMemoryMap(SIZE_CART0);
306#else
307	gba->memory.rom = romBuffer;
308#endif
309	gba->isPristine = false;
310	gba->yankedRomSize = 0;
311	gba->memory.romSize = SIZE_CART0;
312	gba->memory.romMask = SIZE_CART0 - 1;
313	gba->memory.mirroring = false;
314	gba->romCrc32 = 0;
315
316	if (gba->cpu) {
317		gba->cpu->memory.setActiveRegion(gba->cpu, gba->cpu->gprs[ARM_PC]);
318	}
319	return true;
320}
321
322bool GBALoadMB(struct GBA* gba, struct VFile* vf) {
323	GBAUnloadROM(gba);
324	gba->romVf = vf;
325	gba->pristineRomSize = vf->size(vf);
326	vf->seek(vf, 0, SEEK_SET);
327	if (gba->pristineRomSize > SIZE_WORKING_RAM) {
328		gba->pristineRomSize = SIZE_WORKING_RAM;
329	}
330	gba->isPristine = true;
331	gba->memory.wram = anonymousMemoryMap(SIZE_WORKING_RAM);
332	memset(gba->memory.wram, 0, SIZE_WORKING_RAM);
333	vf->read(vf, gba->memory.wram, gba->pristineRomSize);
334	if (!gba->memory.wram) {
335		mLOG(GBA, WARN, "Couldn't map ROM");
336		return false;
337	}
338	gba->yankedRomSize = 0;
339	gba->memory.romSize = 0;
340	gba->memory.romMask = 0;
341	gba->romCrc32 = doCrc32(gba->memory.wram, gba->pristineRomSize);
342	if (gba->cpu && gba->memory.activeRegion == REGION_WORKING_RAM) {
343		gba->cpu->memory.setActiveRegion(gba->cpu, gba->cpu->gprs[ARM_PC]);
344	}
345	return true;
346}
347
348bool GBALoadROM(struct GBA* gba, struct VFile* vf) {
349	if (!vf) {
350		return false;
351	}
352	GBAUnloadROM(gba);
353	gba->romVf = vf;
354	gba->pristineRomSize = vf->size(vf);
355	vf->seek(vf, 0, SEEK_SET);
356	if (gba->pristineRomSize > SIZE_CART0) {
357		gba->pristineRomSize = SIZE_CART0;
358	}
359	gba->isPristine = true;
360#ifdef FIXED_ROM_BUFFER
361	if (gba->pristineRomSize <= romBufferSize) {
362		gba->memory.rom = romBuffer;
363		vf->read(vf, romBuffer, gba->pristineRomSize);
364	}
365#else
366	gba->memory.rom = vf->map(vf, gba->pristineRomSize, MAP_READ);
367#endif
368	if (!gba->memory.rom) {
369		mLOG(GBA, WARN, "Couldn't map ROM");
370		return false;
371	}
372	gba->yankedRomSize = 0;
373	gba->memory.romSize = gba->pristineRomSize;
374	gba->memory.romMask = toPow2(gba->memory.romSize) - 1;
375	gba->memory.mirroring = false;
376	gba->romCrc32 = doCrc32(gba->memory.rom, gba->memory.romSize);
377	GBAHardwareInit(&gba->memory.hw, &((uint16_t*) gba->memory.rom)[GPIO_REG_DATA >> 1]);
378	GBAVFameDetect(&gba->memory.vfame, gba->memory.rom, gba->memory.romSize);
379	if (popcount32(gba->memory.romSize) != 1) {
380		// This ROM is either a bad dump or homebrew. Emulate flash cart behavior.
381#ifndef FIXED_ROM_BUFFER
382		void* newRom = anonymousMemoryMap(SIZE_CART0);
383		memcpy(newRom, gba->memory.rom, gba->pristineRomSize);
384		gba->memory.rom = newRom;
385#endif
386		gba->memory.romSize = SIZE_CART0;
387		gba->isPristine = false;
388	}
389	if (gba->cpu && gba->memory.activeRegion >= REGION_CART0) {
390		gba->cpu->memory.setActiveRegion(gba->cpu, gba->cpu->gprs[ARM_PC]);
391	}
392	// TODO: error check
393	return true;
394}
395
396bool GBALoadSave(struct GBA* gba, struct VFile* sav) {
397	GBASavedataInit(&gba->memory.savedata, sav);
398	return true;
399}
400
401void GBAYankROM(struct GBA* gba) {
402	gba->yankedRomSize = gba->memory.romSize;
403	gba->memory.romSize = 0;
404	gba->memory.romMask = 0;
405	GBARaiseIRQ(gba, IRQ_GAMEPAK);
406}
407
408void GBALoadBIOS(struct GBA* gba, struct VFile* vf) {
409	gba->biosVf = vf;
410	uint32_t* bios = vf->map(vf, SIZE_BIOS, MAP_READ);
411	if (!bios) {
412		mLOG(GBA, WARN, "Couldn't map BIOS");
413		return;
414	}
415	gba->memory.bios = bios;
416	gba->memory.fullBios = 1;
417	uint32_t checksum = GBAChecksum(gba->memory.bios, SIZE_BIOS);
418	mLOG(GBA, DEBUG, "BIOS Checksum: 0x%X", checksum);
419	if (checksum == GBA_BIOS_CHECKSUM) {
420		mLOG(GBA, INFO, "Official GBA BIOS detected");
421	} else if (checksum == GBA_DS_BIOS_CHECKSUM) {
422		mLOG(GBA, INFO, "Official GBA (DS) BIOS detected");
423	} else {
424		mLOG(GBA, WARN, "BIOS checksum incorrect");
425	}
426	gba->biosChecksum = checksum;
427	if (gba->memory.activeRegion == REGION_BIOS) {
428		gba->cpu->memory.activeRegion = gba->memory.bios;
429	}
430	// TODO: error check
431}
432
433void GBAApplyPatch(struct GBA* gba, struct Patch* patch) {
434	size_t patchedSize = patch->outputSize(patch, gba->memory.romSize);
435	if (!patchedSize || patchedSize > SIZE_CART0) {
436		return;
437	}
438	void* newRom = anonymousMemoryMap(SIZE_CART0);
439	if (!patch->applyPatch(patch, gba->memory.rom, gba->pristineRomSize, newRom, patchedSize)) {
440		mappedMemoryFree(newRom, SIZE_CART0);
441		return;
442	}
443	if (gba->romVf) {
444#ifndef FIXED_ROM_BUFFER
445		gba->romVf->unmap(gba->romVf, gba->memory.rom, gba->pristineRomSize);
446#endif
447		gba->romVf->close(gba->romVf);
448		gba->romVf = NULL;
449	}
450	gba->isPristine = false;
451	gba->memory.rom = newRom;
452	gba->memory.hw.gpioBase = &((uint16_t*) gba->memory.rom)[GPIO_REG_DATA >> 1];
453	gba->memory.romSize = patchedSize;
454	gba->memory.romMask = SIZE_CART0 - 1;
455	gba->romCrc32 = doCrc32(gba->memory.rom, gba->memory.romSize);
456}
457
458void GBAWriteIE(struct GBA* gba, uint16_t value) {
459	if (gba->memory.io[REG_IME >> 1] && value & gba->memory.io[REG_IF >> 1]) {
460		ARMRaiseIRQ(gba->cpu);
461	}
462}
463
464void GBAWriteIME(struct GBA* gba, uint16_t value) {
465	if (value && gba->memory.io[REG_IE >> 1] & gba->memory.io[REG_IF >> 1]) {
466		ARMRaiseIRQ(gba->cpu);
467	}
468}
469
470void GBARaiseIRQ(struct GBA* gba, enum GBAIRQ irq) {
471	gba->memory.io[REG_IF >> 1] |= 1 << irq;
472
473	if (gba->memory.io[REG_IE >> 1] & 1 << irq) {
474		gba->cpu->halted = 0;
475		if (gba->memory.io[REG_IME >> 1]) {
476			ARMRaiseIRQ(gba->cpu);
477		}
478	}
479}
480
481void GBATestIRQ(struct ARMCore* cpu) {
482	struct GBA* gba = (struct GBA*) cpu->master;
483	if (gba->memory.io[REG_IME >> 1] && gba->memory.io[REG_IE >> 1] & gba->memory.io[REG_IF >> 1]) {
484		gba->springIRQ = gba->memory.io[REG_IE >> 1] & gba->memory.io[REG_IF >> 1];
485		gba->cpu->nextEvent = gba->cpu->cycles;
486	}
487}
488
489void GBAHalt(struct GBA* gba) {
490	gba->cpu->nextEvent = gba->cpu->cycles;
491	gba->cpu->halted = 1;
492}
493
494void GBAStop(struct GBA* gba) {
495	size_t c;
496	for (c = 0; c < mCoreCallbacksListSize(&gba->coreCallbacks); ++c) {
497		struct mCoreCallbacks* callbacks = mCoreCallbacksListGetPointer(&gba->coreCallbacks, c);
498		if (callbacks->sleep) {
499			callbacks->sleep(callbacks->context);
500		}
501	}
502	gba->cpu->nextEvent = gba->cpu->cycles;
503}
504
505void GBADebug(struct GBA* gba, uint16_t flags) {
506	gba->debugFlags = flags;
507	if (GBADebugFlagsIsSend(gba->debugFlags)) {
508		int level = 1 << GBADebugFlagsGetLevel(gba->debugFlags);
509		level &= 0x1F;
510		char oolBuf[0x101];
511		strncpy(oolBuf, gba->debugString, sizeof(gba->debugString));
512		oolBuf[0x100] = '\0';
513		mLog(_mLOG_CAT_GBA_DEBUG(), level, "%s", oolBuf);
514	}
515	gba->debugFlags = GBADebugFlagsClearSend(gba->debugFlags);
516}
517
518bool GBAIsROM(struct VFile* vf) {
519#ifdef USE_ELF
520	struct ELF* elf = ELFOpen(vf);
521	if (elf) {
522		uint32_t entry = ELFEntry(elf);
523		bool isGBA = true;
524		isGBA = isGBA && ELFMachine(elf) == EM_ARM;
525		isGBA = isGBA && (entry == BASE_CART0 || entry == BASE_WORKING_RAM);
526		ELFClose(elf);
527		return isGBA;
528	}
529#endif
530	if (!vf) {
531		return false;
532	}
533	if (vf->seek(vf, GBA_ROM_MAGIC_OFFSET, SEEK_SET) < 0) {
534		return false;
535	}
536	uint8_t signature[sizeof(GBA_ROM_MAGIC)];
537	if (vf->read(vf, &signature, sizeof(signature)) != sizeof(signature)) {
538		return false;
539	}
540	if (GBAIsBIOS(vf)) {
541		return false;
542	}
543	return memcmp(signature, GBA_ROM_MAGIC, sizeof(signature)) == 0;
544}
545
546bool GBAIsMB(struct VFile* vf) {
547	if (!GBAIsROM(vf)) {
548		return false;
549	}
550#ifdef USE_ELF
551	struct ELF* elf = ELFOpen(vf);
552	if (elf) {
553		bool isMB = ELFEntry(elf) == BASE_WORKING_RAM;
554		ELFClose(elf);
555		return isMB;
556	}
557#endif
558	if (vf->size(vf) > SIZE_WORKING_RAM) {
559		return false;
560	}
561	if (vf->seek(vf, GBA_MB_MAGIC_OFFSET, SEEK_SET) < 0) {
562		return false;
563	}
564	uint32_t signature;
565	if (vf->read(vf, &signature, sizeof(signature)) != sizeof(signature)) {
566		return false;
567	}
568	uint32_t opcode;
569	LOAD_32(opcode, 0, &signature);
570	struct ARMInstructionInfo info;
571	ARMDecodeARM(opcode, &info);
572	if (info.branchType == ARM_BRANCH) {
573		if (info.op1.immediate <= 0) {
574			return false;
575		} else if (info.op1.immediate == 28) {
576			// Ancient toolchain that is known to throw MB detection for a loop
577			return false;
578		} else if (info.op1.immediate != 24) {
579			return true;
580		}
581	}
582
583	uint32_t pc = GBA_MB_MAGIC_OFFSET;
584	int i;
585	for (i = 0; i < 80; ++i) {
586		if (vf->read(vf, &signature, sizeof(signature)) != sizeof(signature)) {
587			break;
588		}
589		pc += 4;
590		LOAD_32(opcode, 0, &signature);
591		ARMDecodeARM(opcode, &info);
592		if (info.mnemonic != ARM_MN_LDR) {
593			continue;
594		}
595		if ((info.operandFormat & ARM_OPERAND_MEMORY) && info.memory.baseReg == ARM_PC && info.memory.format & ARM_MEMORY_IMMEDIATE_OFFSET) {
596			uint32_t immediate = info.memory.offset.immediate;
597			if (info.memory.format & ARM_MEMORY_OFFSET_SUBTRACT) {
598				immediate = -immediate;
599			}
600			immediate += pc + 8;
601			if (vf->seek(vf, immediate, SEEK_SET) < 0) {
602				break;
603			}
604			if (vf->read(vf, &signature, sizeof(signature)) != sizeof(signature)) {
605				break;
606			}
607			LOAD_32(immediate, 0, &signature);
608			if (vf->seek(vf, pc, SEEK_SET) < 0) {
609				break;
610			}
611			if ((immediate & ~0x7FF) == BASE_WORKING_RAM) {
612				return true;
613			}
614		}
615	}
616	// Found a libgba-linked cart...these are a bit harder to detect.
617	return false;
618}
619
620bool GBAIsBIOS(struct VFile* vf) {
621	if (vf->seek(vf, 0, SEEK_SET) < 0) {
622		return false;
623	}
624	uint8_t interruptTable[7 * 4];
625	if (vf->read(vf, &interruptTable, sizeof(interruptTable)) != sizeof(interruptTable)) {
626		return false;
627	}
628	int i;
629	for (i = 0; i < 7; ++i) {
630		if (interruptTable[4 * i + 3] != 0xEA || interruptTable[4 * i + 2]) {
631			return false;
632		}
633	}
634	return true;
635}
636
637void GBAGetGameCode(const struct GBA* gba, char* out) {
638	memset(out, 0, 8);
639	if (!gba->memory.rom) {
640		return;
641	}
642
643	memcpy(out, "AGB-", 4);
644	memcpy(&out[4], &((struct GBACartridge*) gba->memory.rom)->id, 4);
645}
646
647void GBAGetGameTitle(const struct GBA* gba, char* out) {
648	if (gba->memory.rom) {
649		memcpy(out, &((struct GBACartridge*) gba->memory.rom)->title, 12);
650		return;
651	}
652	if (gba->isPristine && gba->memory.wram) {
653		memcpy(out, &((struct GBACartridge*) gba->memory.wram)->title, 12);
654		return;
655	}
656	strncpy(out, "(BIOS)", 12);
657}
658
659void GBAHitStub(struct ARMCore* cpu, uint32_t opcode) {
660	struct GBA* gba = (struct GBA*) cpu->master;
661#ifdef USE_DEBUGGERS
662	if (gba->debugger) {
663		struct mDebuggerEntryInfo info = {
664			.address = _ARMPCAddress(cpu),
665			.opcode = opcode
666		};
667		mDebuggerEnter(gba->debugger->d.p, DEBUGGER_ENTER_ILLEGAL_OP, &info);
668	}
669#endif
670	// TODO: More sensible category?
671	mLOG(GBA, ERROR, "Stub opcode: %08x", opcode);
672}
673
674void GBAIllegal(struct ARMCore* cpu, uint32_t opcode) {
675	struct GBA* gba = (struct GBA*) cpu->master;
676	if (!gba->yankedRomSize) {
677		// TODO: More sensible category?
678		mLOG(GBA, WARN, "Illegal opcode: %08x", opcode);
679	}
680	if (cpu->executionMode == MODE_THUMB && (opcode & 0xFFC0) == 0xE800) {
681		mLOG(GBA, DEBUG, "Hit Wii U VC opcode: %08x", opcode);
682		return;
683	}
684#ifdef USE_DEBUGGERS
685	if (gba->debugger) {
686		struct mDebuggerEntryInfo info = {
687			.address = _ARMPCAddress(cpu),
688			.opcode = opcode
689		};
690		mDebuggerEnter(gba->debugger->d.p, DEBUGGER_ENTER_ILLEGAL_OP, &info);
691	} else
692#endif
693	{
694		ARMRaiseUndefined(cpu);
695	}
696}
697
698void GBABreakpoint(struct ARMCore* cpu, int immediate) {
699	struct GBA* gba = (struct GBA*) cpu->master;
700	if (immediate >= CPU_COMPONENT_MAX) {
701		return;
702	}
703	switch (immediate) {
704#ifdef USE_DEBUGGERS
705	case CPU_COMPONENT_DEBUGGER:
706		if (gba->debugger) {
707			struct mDebuggerEntryInfo info = {
708				.address = _ARMPCAddress(cpu),
709				.breakType = BREAKPOINT_SOFTWARE
710			};
711			mDebuggerEnter(gba->debugger->d.p, DEBUGGER_ENTER_BREAKPOINT, &info);
712		}
713		break;
714#endif
715	case CPU_COMPONENT_CHEAT_DEVICE:
716		if (gba->cpu->components[CPU_COMPONENT_CHEAT_DEVICE]) {
717			struct mCheatDevice* device = (struct mCheatDevice*) gba->cpu->components[CPU_COMPONENT_CHEAT_DEVICE];
718			struct GBACheatHook* hook = 0;
719			size_t i;
720			for (i = 0; i < mCheatSetsSize(&device->cheats); ++i) {
721				struct GBACheatSet* cheats = (struct GBACheatSet*) *mCheatSetsGetPointer(&device->cheats, i);
722				if (cheats->hook && cheats->hook->address == _ARMPCAddress(cpu)) {
723					mCheatRefresh(device, &cheats->d);
724					hook = cheats->hook;
725				}
726			}
727			if (hook) {
728				ARMRunFake(cpu, hook->patchedOpcode);
729			}
730		}
731		break;
732	default:
733		break;
734	}
735}
736
737void GBAFrameStarted(struct GBA* gba) {
738	GBATestKeypadIRQ(gba);
739
740	size_t c;
741	for (c = 0; c < mCoreCallbacksListSize(&gba->coreCallbacks); ++c) {
742		struct mCoreCallbacks* callbacks = mCoreCallbacksListGetPointer(&gba->coreCallbacks, c);
743		if (callbacks->videoFrameStarted) {
744			callbacks->videoFrameStarted(callbacks->context);
745		}
746	}
747}
748
749void GBAFrameEnded(struct GBA* gba) {
750	GBASavedataClean(&gba->memory.savedata, gba->video.frameCounter);
751
752	if (gba->rr) {
753		gba->rr->nextFrame(gba->rr);
754	}
755
756	if (gba->cpu->components && gba->cpu->components[CPU_COMPONENT_CHEAT_DEVICE]) {
757		struct mCheatDevice* device = (struct mCheatDevice*) gba->cpu->components[CPU_COMPONENT_CHEAT_DEVICE];
758		size_t i;
759		for (i = 0; i < mCheatSetsSize(&device->cheats); ++i) {
760			struct GBACheatSet* cheats = (struct GBACheatSet*) *mCheatSetsGetPointer(&device->cheats, i);
761			mCheatRefresh(device, &cheats->d);
762		}
763	}
764
765	if (gba->stream && gba->stream->postVideoFrame) {
766		const color_t* pixels;
767		size_t stride;
768		gba->video.renderer->getPixels(gba->video.renderer, &stride, (const void**) &pixels);
769		gba->stream->postVideoFrame(gba->stream, pixels, stride);
770	}
771
772	if (gba->memory.hw.devices & (HW_GB_PLAYER | HW_GB_PLAYER_DETECTION)) {
773		GBAHardwarePlayerUpdate(gba);
774	}
775
776	size_t c;
777	for (c = 0; c < mCoreCallbacksListSize(&gba->coreCallbacks); ++c) {
778		struct mCoreCallbacks* callbacks = mCoreCallbacksListGetPointer(&gba->coreCallbacks, c);
779		if (callbacks->videoFrameEnded) {
780			callbacks->videoFrameEnded(callbacks->context);
781		}
782	}
783}
784
785void GBATestKeypadIRQ(struct GBA* gba) {
786	uint16_t keycnt = gba->memory.io[REG_KEYCNT >> 1];
787	if (!(keycnt & 0x4000)) {
788		return;
789	}
790	int isAnd = keycnt & 0x8000;
791	if (!gba->keySource) {
792		// TODO?
793		return;
794	}
795
796	keycnt &= 0x3FF;
797	uint16_t keyInput = *gba->keySource & keycnt;
798
799	if (isAnd && keycnt == keyInput) {
800		GBARaiseIRQ(gba, IRQ_KEYPAD);
801	} else if (!isAnd && keyInput) {
802		GBARaiseIRQ(gba, IRQ_KEYPAD);
803	}
804}
805
806void GBASetBreakpoint(struct GBA* gba, struct mCPUComponent* component, uint32_t address, enum ExecutionMode mode, uint32_t* opcode) {
807	size_t immediate;
808	for (immediate = 0; immediate < gba->cpu->numComponents; ++immediate) {
809		if (gba->cpu->components[immediate] == component) {
810			break;
811		}
812	}
813	if (immediate == gba->cpu->numComponents) {
814		return;
815	}
816	if (mode == MODE_ARM) {
817		int32_t value;
818		int32_t old;
819		value = 0xE1200070;
820		value |= immediate & 0xF;
821		value |= (immediate & 0xFFF0) << 4;
822		GBAPatch32(gba->cpu, address, value, &old);
823		*opcode = old;
824	} else {
825		int16_t value;
826		int16_t old;
827		value = 0xBE00;
828		value |= immediate & 0xFF;
829		GBAPatch16(gba->cpu, address, value, &old);
830		*opcode = (uint16_t) old;
831	}
832}
833
834void GBAClearBreakpoint(struct GBA* gba, uint32_t address, enum ExecutionMode mode, uint32_t opcode) {
835	if (mode == MODE_ARM) {
836		GBAPatch32(gba->cpu, address, opcode, 0);
837	} else {
838		GBAPatch16(gba->cpu, address, opcode, 0);
839	}
840}
841
842static bool _setSoftwareBreakpoint(struct ARMDebugger* debugger, uint32_t address, enum ExecutionMode mode, uint32_t* opcode) {
843	GBASetBreakpoint((struct GBA*) debugger->cpu->master, &debugger->d.p->d, address, mode, opcode);
844	return true;
845}
846
847static bool _clearSoftwareBreakpoint(struct ARMDebugger* debugger, uint32_t address, enum ExecutionMode mode, uint32_t opcode) {
848	GBAClearBreakpoint((struct GBA*) debugger->cpu->master, address, mode, opcode);
849	return true;
850}