src/gb/gb.c (view raw)
1/* Copyright (c) 2013-2016 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 "gb.h"
7
8#include "gb/io.h"
9
10#include "core/core.h"
11#include "util/crc32.h"
12#include "util/memory.h"
13#include "util/math.h"
14#include "util/patch.h"
15#include "util/vfs.h"
16
17const uint32_t CGB_LR35902_FREQUENCY = 0x800000;
18const uint32_t SGB_LR35902_FREQUENCY = 0x418B1E;
19
20const uint32_t GB_COMPONENT_MAGIC = 0x400000;
21
22mLOG_DEFINE_CATEGORY(GB, "GB");
23
24static void GBInit(void* cpu, struct mCPUComponent* component);
25static void GBInterruptHandlerInit(struct LR35902InterruptHandler* irqh);
26static void GBProcessEvents(struct LR35902Core* cpu);
27static void GBSetInterrupts(struct LR35902Core* cpu, bool enable);
28static void GBIllegal(struct LR35902Core* cpu);
29static void GBStop(struct LR35902Core* cpu);
30
31#ifdef _3DS
32extern uint32_t* romBuffer;
33extern size_t romBufferSize;
34#endif
35
36void GBCreate(struct GB* gb) {
37 gb->d.id = GB_COMPONENT_MAGIC;
38 gb->d.init = GBInit;
39 gb->d.deinit = 0;
40}
41
42static void GBInit(void* cpu, struct mCPUComponent* component) {
43 struct GB* gb = (struct GB*) component;
44 gb->cpu = cpu;
45
46 GBInterruptHandlerInit(&gb->cpu->irqh);
47 GBMemoryInit(gb);
48
49 gb->video.p = gb;
50 GBVideoInit(&gb->video);
51
52 gb->audio.p = gb;
53 GBAudioInit(&gb->audio, 2048, &gb->memory.io[REG_NR52], GB_AUDIO_DMG); // TODO: Remove magic constant
54
55 gb->timer.p = gb;
56
57 gb->romVf = 0;
58 gb->sramVf = 0;
59
60 gb->pristineRom = 0;
61 gb->pristineRomSize = 0;
62 gb->yankedRomSize = 0;
63
64 gb->stream = NULL;
65
66 gb->eiPending = false;
67 gb->doubleSpeed = 0;
68}
69
70bool GBLoadROM(struct GB* gb, struct VFile* vf) {
71 GBUnloadROM(gb);
72 gb->romVf = vf;
73 gb->pristineRomSize = vf->size(vf);
74 vf->seek(vf, 0, SEEK_SET);
75#ifdef _3DS
76 gb->pristineRom = 0;
77 if (gb->pristineRomSize <= romBufferSize) {
78 gb->pristineRom = romBuffer;
79 vf->read(vf, romBuffer, gb->pristineRomSize);
80 }
81#else
82 gb->pristineRom = vf->map(vf, gb->pristineRomSize, MAP_READ);
83#endif
84 if (!gb->pristineRom) {
85 return false;
86 }
87 gb->yankedRomSize = 0;
88 gb->memory.rom = gb->pristineRom;
89 gb->memory.romSize = gb->pristineRomSize;
90 gb->romCrc32 = doCrc32(gb->memory.rom, gb->memory.romSize);
91
92 // TODO: error check
93 return true;
94}
95
96bool GBLoadSave(struct GB* gb, struct VFile* vf) {
97 gb->sramVf = vf;
98 if (vf) {
99 // TODO: Do this in bank-switching code
100 if (vf->size(vf) < 0x20000) {
101 vf->truncate(vf, 0x20000);
102 }
103 gb->memory.sram = vf->map(vf, 0x20000, MAP_WRITE);
104 } else {
105 gb->memory.sram = anonymousMemoryMap(0x20000);
106 }
107 return gb->memory.sram;
108}
109
110void GBUnloadROM(struct GB* gb) {
111 // TODO: Share with GBAUnloadROM
112 if (gb->memory.rom && gb->pristineRom != gb->memory.rom) {
113 if (gb->yankedRomSize) {
114 gb->yankedRomSize = 0;
115 }
116 mappedMemoryFree(gb->memory.rom, 0x400000);
117 }
118 gb->memory.rom = 0;
119
120 if (gb->romVf) {
121#ifndef _3DS
122 gb->romVf->unmap(gb->romVf, gb->pristineRom, gb->pristineRomSize);
123#endif
124 gb->pristineRom = 0;
125 gb->romVf = 0;
126 }
127
128 if (gb->sramVf) {
129 gb->sramVf->unmap(gb->sramVf, gb->memory.sram, 0x8000);
130 gb->sramVf = 0;
131 } else if (gb->memory.sram) {
132 mappedMemoryFree(gb->memory.sram, 0x8000);
133 }
134 gb->memory.sram = 0;
135}
136
137void GBApplyPatch(struct GB* gb, struct Patch* patch) {
138 size_t patchedSize = patch->outputSize(patch, gb->memory.romSize);
139 if (!patchedSize) {
140 return;
141 }
142 if (patchedSize > 0x400000) {
143 patchedSize = 0x400000;
144 }
145 gb->memory.rom = anonymousMemoryMap(0x400000);
146 if (!patch->applyPatch(patch, gb->pristineRom, gb->pristineRomSize, gb->memory.rom, patchedSize)) {
147 mappedMemoryFree(gb->memory.rom, patchedSize);
148 gb->memory.rom = gb->pristineRom;
149 return;
150 }
151 gb->memory.romSize = patchedSize;
152 gb->romCrc32 = doCrc32(gb->memory.rom, gb->memory.romSize);
153}
154
155void GBDestroy(struct GB* gb) {
156 GBUnloadROM(gb);
157
158 GBMemoryDeinit(gb);
159}
160
161void GBInterruptHandlerInit(struct LR35902InterruptHandler* irqh) {
162 irqh->reset = GBReset;
163 irqh->processEvents = GBProcessEvents;
164 irqh->setInterrupts = GBSetInterrupts;
165 irqh->hitIllegal = GBIllegal;
166 irqh->stop = GBStop;
167 irqh->halt = GBHalt;
168}
169
170void GBReset(struct LR35902Core* cpu) {
171 struct GB* gb = (struct GB*) cpu->master;
172
173 const struct GBCartridge* cart = (const struct GBCartridge*) &gb->memory.rom[0x100];
174 if (cart->cgb & 0x80) {
175 gb->model = GB_MODEL_CGB;
176 gb->audio.style = GB_AUDIO_CGB;
177 cpu->a = 0x11;
178 } else {
179 // TODO: SGB
180 gb->model = GB_MODEL_DMG;
181 gb->audio.style = GB_AUDIO_DMG;
182 cpu->a = 1;
183 }
184
185 cpu->f.packed = 0xB0;
186 cpu->b = 0;
187 cpu->c = 0x13;
188 cpu->d = 0;
189 cpu->e = 0xD8;
190 cpu->h = 1;
191 cpu->l = 0x4D;
192 cpu->sp = 0xFFFE;
193 cpu->pc = 0x100;
194
195 if (gb->yankedRomSize) {
196 gb->memory.romSize = gb->yankedRomSize;
197 gb->yankedRomSize = 0;
198 }
199 GBMemoryReset(gb);
200 GBVideoReset(&gb->video);
201 GBTimerReset(&gb->timer);
202 GBIOReset(gb);
203 GBAudioReset(&gb->audio);
204}
205
206void GBUpdateIRQs(struct GB* gb) {
207 int irqs = gb->memory.ie & gb->memory.io[REG_IF];
208 if (!irqs) {
209 return;
210 }
211 gb->cpu->halted = false;
212
213 if (!gb->memory.ime) {
214 return;
215 }
216
217 if (irqs & (1 << GB_IRQ_VBLANK)) {
218 LR35902RaiseIRQ(gb->cpu, GB_VECTOR_VBLANK);
219 gb->memory.io[REG_IF] &= ~(1 << GB_IRQ_VBLANK);
220 return;
221 }
222 if (irqs & (1 << GB_IRQ_LCDSTAT)) {
223 LR35902RaiseIRQ(gb->cpu, GB_VECTOR_LCDSTAT);
224 gb->memory.io[REG_IF] &= ~(1 << GB_IRQ_LCDSTAT);
225 return;
226 }
227 if (irqs & (1 << GB_IRQ_TIMER)) {
228 LR35902RaiseIRQ(gb->cpu, GB_VECTOR_TIMER);
229 gb->memory.io[REG_IF] &= ~(1 << GB_IRQ_TIMER);
230 return;
231 }
232 if (irqs & (1 << GB_IRQ_SIO)) {
233 LR35902RaiseIRQ(gb->cpu, GB_VECTOR_SIO);
234 gb->memory.io[REG_IF] &= ~(1 << GB_IRQ_SIO);
235 return;
236 }
237 if (irqs & (1 << GB_IRQ_KEYPAD)) {
238 LR35902RaiseIRQ(gb->cpu, GB_VECTOR_KEYPAD);
239 gb->memory.io[REG_IF] &= ~(1 << GB_IRQ_KEYPAD);
240 }
241}
242
243void GBProcessEvents(struct LR35902Core* cpu) {
244 struct GB* gb = (struct GB*) cpu->master;
245 do {
246 int32_t cycles = cpu->nextEvent;
247 int32_t nextEvent = INT_MAX;
248 int32_t testEvent;
249
250 if (gb->eiPending) {
251 gb->eiPending -= cycles;
252 if (gb->eiPending <= 0) {
253 gb->memory.ime = true;
254 GBUpdateIRQs(gb);
255 gb->eiPending = 0;
256 }
257 }
258
259 testEvent = GBVideoProcessEvents(&gb->video, cycles >> gb->doubleSpeed);
260 if (testEvent != INT_MAX) {
261 testEvent <<= gb->doubleSpeed;
262 if (testEvent < nextEvent) {
263 nextEvent = testEvent;
264 }
265 }
266
267 testEvent = GBAudioProcessEvents(&gb->audio, cycles >> gb->doubleSpeed);
268 if (testEvent != INT_MAX) {
269 testEvent <<= gb->doubleSpeed;
270 if (testEvent < nextEvent) {
271 nextEvent = testEvent;
272 }
273 }
274
275 testEvent = GBTimerProcessEvents(&gb->timer, cycles);
276 if (testEvent < nextEvent) {
277 nextEvent = testEvent;
278 }
279
280 testEvent = GBMemoryProcessEvents(gb, cycles);
281 if (testEvent < nextEvent) {
282 nextEvent = testEvent;
283 }
284
285 cpu->cycles -= cycles;
286 cpu->nextEvent = nextEvent;
287
288 if (cpu->halted) {
289 cpu->cycles = cpu->nextEvent;
290 }
291 } while (cpu->cycles >= cpu->nextEvent);
292}
293
294void GBSetInterrupts(struct LR35902Core* cpu, bool enable) {
295 struct GB* gb = (struct GB*) cpu->master;
296 if (!enable) {
297 gb->memory.ime = enable;
298 gb->eiPending = 0;
299 GBUpdateIRQs(gb);
300 } else {
301 if (cpu->nextEvent > cpu->cycles + 4) {
302 cpu->nextEvent = cpu->cycles + 4;
303 }
304 gb->eiPending = cpu->cycles + 4;
305 }
306}
307
308void GBHalt(struct LR35902Core* cpu) {
309 cpu->cycles = cpu->nextEvent;
310 cpu->halted = true;
311}
312
313void GBStop(struct LR35902Core* cpu) {
314 struct GB* gb = (struct GB*) cpu->master;
315 if (gb->memory.io[REG_KEY1] & 1) {
316 gb->doubleSpeed ^= 1;
317 gb->memory.io[REG_KEY1] &= 1;
318 gb->memory.io[REG_KEY1] |= gb->doubleSpeed << 7;
319 }
320 // TODO: Actually stop
321}
322
323void GBIllegal(struct LR35902Core* cpu) {
324 // TODO
325 mLOG(GB, GAME_ERROR, "Hit illegal opcode at address %04X:%02X\n", cpu->pc, cpu->bus);
326}
327
328bool GBIsROM(struct VFile* vf) {
329 vf->seek(vf, 0x104, SEEK_SET);
330 uint8_t header[4];
331 static const uint8_t knownHeader[4] = { 0xCE, 0xED, 0x66, 0x66};
332
333 if (vf->read(vf, &header, sizeof(header)) < (ssize_t) sizeof(header)) {
334 return false;
335 }
336 if (memcmp(header, knownHeader, sizeof(header))) {
337 return false;
338 }
339 return true;
340}
341
342void GBGetGameTitle(struct GB* gb, char* out) {
343 const struct GBCartridge* cart = NULL;
344 if (gb->memory.rom) {
345 cart = (const struct GBCartridge*) &gb->memory.rom[0x100];
346 }
347 if (gb->pristineRom) {
348 cart = (const struct GBCartridge*) &((uint8_t*) gb->pristineRom)[0x100];
349 }
350 if (!cart) {
351 return;
352 }
353 if (cart->oldLicensee != 0x33) {
354 memcpy(out, cart->titleLong, 16);
355 } else {
356 memcpy(out, cart->titleShort, 11);
357 }
358}
359
360void GBGetGameCode(struct GB* gb, char* out) {
361 memset(out, 0, 4);
362 const struct GBCartridge* cart = NULL;
363 if (gb->memory.rom) {
364 cart = (const struct GBCartridge*) &gb->memory.rom[0x100];
365 }
366 if (gb->pristineRom) {
367 cart = (const struct GBCartridge*) &((uint8_t*) gb->pristineRom)[0x100];
368 }
369 if (!cart) {
370 return;
371 }
372 if (cart->oldLicensee == 0x33) {
373 memcpy(out, cart->maker, 11);
374 }
375}