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 gb->sync = NULL;
46
47 GBInterruptHandlerInit(&gb->cpu->irqh);
48 GBMemoryInit(gb);
49
50 gb->video.p = gb;
51 GBVideoInit(&gb->video);
52
53 gb->audio.p = gb;
54 GBAudioInit(&gb->audio, 2048, &gb->memory.io[REG_NR52], GB_AUDIO_DMG); // TODO: Remove magic constant
55
56 gb->timer.p = gb;
57
58 gb->romVf = 0;
59 gb->sramVf = 0;
60
61 gb->pristineRom = 0;
62 gb->pristineRomSize = 0;
63 gb->yankedRomSize = 0;
64
65 gb->stream = NULL;
66
67 gb->eiPending = false;
68 gb->doubleSpeed = 0;
69}
70
71bool GBLoadROM(struct GB* gb, struct VFile* vf) {
72 GBUnloadROM(gb);
73 gb->romVf = vf;
74 gb->pristineRomSize = vf->size(vf);
75 vf->seek(vf, 0, SEEK_SET);
76#ifdef _3DS
77 gb->pristineRom = 0;
78 if (gb->pristineRomSize <= romBufferSize) {
79 gb->pristineRom = romBuffer;
80 vf->read(vf, romBuffer, gb->pristineRomSize);
81 }
82#else
83 gb->pristineRom = vf->map(vf, gb->pristineRomSize, MAP_READ);
84#endif
85 if (!gb->pristineRom) {
86 return false;
87 }
88 gb->yankedRomSize = 0;
89 gb->memory.rom = gb->pristineRom;
90 gb->memory.romSize = gb->pristineRomSize;
91 gb->romCrc32 = doCrc32(gb->memory.rom, gb->memory.romSize);
92
93 // TODO: error check
94 return true;
95}
96
97bool GBLoadSave(struct GB* gb, struct VFile* vf) {
98 gb->sramVf = vf;
99 if (vf) {
100 // TODO: Do this in bank-switching code
101 if (vf->size(vf) < 0x20000) {
102 vf->truncate(vf, 0x20000);
103 }
104 gb->memory.sram = vf->map(vf, 0x20000, MAP_WRITE);
105 }
106 return gb->memory.sram;
107}
108
109void GBUnloadROM(struct GB* gb) {
110 // TODO: Share with GBAUnloadROM
111 if (gb->memory.rom && gb->pristineRom != gb->memory.rom) {
112 if (gb->yankedRomSize) {
113 gb->yankedRomSize = 0;
114 }
115 mappedMemoryFree(gb->memory.rom, GB_SIZE_CART_MAX);
116 }
117 gb->memory.rom = 0;
118
119 if (gb->romVf) {
120#ifndef _3DS
121 gb->romVf->unmap(gb->romVf, gb->pristineRom, gb->pristineRomSize);
122#endif
123 gb->romVf->close(gb->romVf);
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 > GB_SIZE_CART_MAX) {
143 patchedSize = GB_SIZE_CART_MAX;
144 }
145 gb->memory.rom = anonymousMemoryMap(GB_SIZE_CART_MAX);
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 cpu->f.packed = 0x80;
179 cpu->c = 0;
180 cpu->e = 0x08;
181 cpu->h = 0;
182 cpu->l = 0x7C;
183 } else {
184 // TODO: SGB
185 gb->model = GB_MODEL_DMG;
186 gb->audio.style = GB_AUDIO_DMG;
187 cpu->a = 1;
188 cpu->f.packed = 0xB0;
189 cpu->c = 0x13;
190 cpu->e = 0xD8;
191 cpu->h = 1;
192 cpu->l = 0x4D;
193 }
194 cpu->b = 0;
195 cpu->d = 0;
196 cpu->sp = 0xFFFE;
197 cpu->pc = 0x100;
198
199 if (gb->yankedRomSize) {
200 gb->memory.romSize = gb->yankedRomSize;
201 gb->yankedRomSize = 0;
202 }
203 GBMemoryReset(gb);
204 GBVideoReset(&gb->video);
205 GBTimerReset(&gb->timer);
206 GBIOReset(gb);
207 GBAudioReset(&gb->audio);
208}
209
210void GBUpdateIRQs(struct GB* gb) {
211 int irqs = gb->memory.ie & gb->memory.io[REG_IF];
212 if (!irqs) {
213 return;
214 }
215 gb->cpu->halted = false;
216
217 if (!gb->memory.ime) {
218 return;
219 }
220
221 if (irqs & (1 << GB_IRQ_VBLANK)) {
222 LR35902RaiseIRQ(gb->cpu, GB_VECTOR_VBLANK);
223 gb->memory.io[REG_IF] &= ~(1 << GB_IRQ_VBLANK);
224 return;
225 }
226 if (irqs & (1 << GB_IRQ_LCDSTAT)) {
227 LR35902RaiseIRQ(gb->cpu, GB_VECTOR_LCDSTAT);
228 gb->memory.io[REG_IF] &= ~(1 << GB_IRQ_LCDSTAT);
229 return;
230 }
231 if (irqs & (1 << GB_IRQ_TIMER)) {
232 LR35902RaiseIRQ(gb->cpu, GB_VECTOR_TIMER);
233 gb->memory.io[REG_IF] &= ~(1 << GB_IRQ_TIMER);
234 return;
235 }
236 if (irqs & (1 << GB_IRQ_SIO)) {
237 LR35902RaiseIRQ(gb->cpu, GB_VECTOR_SIO);
238 gb->memory.io[REG_IF] &= ~(1 << GB_IRQ_SIO);
239 return;
240 }
241 if (irqs & (1 << GB_IRQ_KEYPAD)) {
242 LR35902RaiseIRQ(gb->cpu, GB_VECTOR_KEYPAD);
243 gb->memory.io[REG_IF] &= ~(1 << GB_IRQ_KEYPAD);
244 }
245}
246
247void GBProcessEvents(struct LR35902Core* cpu) {
248 struct GB* gb = (struct GB*) cpu->master;
249 do {
250 int32_t cycles = cpu->nextEvent;
251 int32_t nextEvent = INT_MAX;
252 int32_t testEvent;
253
254 if (gb->eiPending) {
255 gb->eiPending -= cycles;
256 if (gb->eiPending <= 0) {
257 gb->memory.ime = true;
258 GBUpdateIRQs(gb);
259 gb->eiPending = 0;
260 }
261 }
262
263 testEvent = GBVideoProcessEvents(&gb->video, cycles >> gb->doubleSpeed);
264 if (testEvent != INT_MAX) {
265 testEvent <<= gb->doubleSpeed;
266 if (testEvent < nextEvent) {
267 nextEvent = testEvent;
268 }
269 }
270
271 testEvent = GBAudioProcessEvents(&gb->audio, cycles >> gb->doubleSpeed);
272 if (testEvent != INT_MAX) {
273 testEvent <<= gb->doubleSpeed;
274 if (testEvent < nextEvent) {
275 nextEvent = testEvent;
276 }
277 }
278
279 testEvent = GBTimerProcessEvents(&gb->timer, cycles);
280 if (testEvent < nextEvent) {
281 nextEvent = testEvent;
282 }
283
284 testEvent = GBMemoryProcessEvents(gb, cycles);
285 if (testEvent < nextEvent) {
286 nextEvent = testEvent;
287 }
288
289 cpu->cycles -= cycles;
290 cpu->nextEvent = nextEvent;
291
292 if (cpu->halted) {
293 cpu->cycles = cpu->nextEvent;
294 }
295 } while (cpu->cycles >= cpu->nextEvent);
296}
297
298void GBSetInterrupts(struct LR35902Core* cpu, bool enable) {
299 struct GB* gb = (struct GB*) cpu->master;
300 if (!enable) {
301 gb->memory.ime = enable;
302 gb->eiPending = 0;
303 GBUpdateIRQs(gb);
304 } else {
305 if (cpu->nextEvent > cpu->cycles + 4) {
306 cpu->nextEvent = cpu->cycles + 4;
307 }
308 gb->eiPending = cpu->cycles + 4;
309 }
310}
311
312void GBHalt(struct LR35902Core* cpu) {
313 cpu->cycles = cpu->nextEvent;
314 cpu->halted = true;
315}
316
317void GBStop(struct LR35902Core* cpu) {
318 struct GB* gb = (struct GB*) cpu->master;
319 if (gb->memory.io[REG_KEY1] & 1) {
320 gb->doubleSpeed ^= 1;
321 gb->memory.io[REG_KEY1] &= 1;
322 gb->memory.io[REG_KEY1] |= gb->doubleSpeed << 7;
323 }
324 // TODO: Actually stop
325}
326
327void GBIllegal(struct LR35902Core* cpu) {
328 // TODO
329 mLOG(GB, GAME_ERROR, "Hit illegal opcode at address %04X:%02X\n", cpu->pc, cpu->bus);
330}
331
332bool GBIsROM(struct VFile* vf) {
333 vf->seek(vf, 0x104, SEEK_SET);
334 uint8_t header[4];
335 static const uint8_t knownHeader[4] = { 0xCE, 0xED, 0x66, 0x66};
336
337 if (vf->read(vf, &header, sizeof(header)) < (ssize_t) sizeof(header)) {
338 return false;
339 }
340 if (memcmp(header, knownHeader, sizeof(header))) {
341 return false;
342 }
343 return true;
344}
345
346void GBGetGameTitle(struct GB* gb, char* out) {
347 const struct GBCartridge* cart = NULL;
348 if (gb->memory.rom) {
349 cart = (const struct GBCartridge*) &gb->memory.rom[0x100];
350 }
351 if (gb->pristineRom) {
352 cart = (const struct GBCartridge*) &((uint8_t*) gb->pristineRom)[0x100];
353 }
354 if (!cart) {
355 return;
356 }
357 if (cart->oldLicensee != 0x33) {
358 memcpy(out, cart->titleLong, 16);
359 } else {
360 memcpy(out, cart->titleShort, 11);
361 }
362}
363
364void GBGetGameCode(struct GB* gb, char* out) {
365 memset(out, 0, 8);
366 const struct GBCartridge* cart = NULL;
367 if (gb->memory.rom) {
368 cart = (const struct GBCartridge*) &gb->memory.rom[0x100];
369 }
370 if (gb->pristineRom) {
371 cart = (const struct GBCartridge*) &((uint8_t*) gb->pristineRom)[0x100];
372 }
373 if (!cart) {
374 return;
375 }
376 if (cart->cgb == 0xC0) {
377 memcpy(out, "CGB-????", 8);
378 } else {
379 memcpy(out, "DMG-????", 8);
380 }
381 if (cart->oldLicensee == 0x33) {
382 memcpy(&out[4], cart->maker, 4);
383 }
384}