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 } else {
106 gb->memory.sram = anonymousMemoryMap(0x20000);
107 }
108 return gb->memory.sram;
109}
110
111void GBUnloadROM(struct GB* gb) {
112 // TODO: Share with GBAUnloadROM
113 if (gb->memory.rom && gb->pristineRom != gb->memory.rom) {
114 if (gb->yankedRomSize) {
115 gb->yankedRomSize = 0;
116 }
117 mappedMemoryFree(gb->memory.rom, 0x400000);
118 }
119 gb->memory.rom = 0;
120
121 if (gb->romVf) {
122#ifndef _3DS
123 gb->romVf->unmap(gb->romVf, gb->pristineRom, gb->pristineRomSize);
124#endif
125 gb->pristineRom = 0;
126 gb->romVf = 0;
127 }
128
129 if (gb->sramVf) {
130 gb->sramVf->unmap(gb->sramVf, gb->memory.sram, 0x8000);
131 gb->sramVf = 0;
132 } else if (gb->memory.sram) {
133 mappedMemoryFree(gb->memory.sram, 0x8000);
134 }
135 gb->memory.sram = 0;
136}
137
138void GBApplyPatch(struct GB* gb, struct Patch* patch) {
139 size_t patchedSize = patch->outputSize(patch, gb->memory.romSize);
140 if (!patchedSize) {
141 return;
142 }
143 if (patchedSize > 0x400000) {
144 patchedSize = 0x400000;
145 }
146 gb->memory.rom = anonymousMemoryMap(0x400000);
147 if (!patch->applyPatch(patch, gb->pristineRom, gb->pristineRomSize, gb->memory.rom, patchedSize)) {
148 mappedMemoryFree(gb->memory.rom, patchedSize);
149 gb->memory.rom = gb->pristineRom;
150 return;
151 }
152 gb->memory.romSize = patchedSize;
153 gb->romCrc32 = doCrc32(gb->memory.rom, gb->memory.romSize);
154}
155
156void GBDestroy(struct GB* gb) {
157 GBUnloadROM(gb);
158
159 GBMemoryDeinit(gb);
160}
161
162void GBInterruptHandlerInit(struct LR35902InterruptHandler* irqh) {
163 irqh->reset = GBReset;
164 irqh->processEvents = GBProcessEvents;
165 irqh->setInterrupts = GBSetInterrupts;
166 irqh->hitIllegal = GBIllegal;
167 irqh->stop = GBStop;
168 irqh->halt = GBHalt;
169}
170
171void GBReset(struct LR35902Core* cpu) {
172 struct GB* gb = (struct GB*) cpu->master;
173
174 const struct GBCartridge* cart = (const struct GBCartridge*) &gb->memory.rom[0x100];
175 if (cart->cgb & 0x80) {
176 gb->model = GB_MODEL_CGB;
177 gb->audio.style = GB_AUDIO_CGB;
178 cpu->a = 0x11;
179 } else {
180 // TODO: SGB
181 gb->model = GB_MODEL_DMG;
182 gb->audio.style = GB_AUDIO_DMG;
183 cpu->a = 1;
184 }
185
186 cpu->f.packed = 0xB0;
187 cpu->b = 0;
188 cpu->c = 0x13;
189 cpu->d = 0;
190 cpu->e = 0xD8;
191 cpu->h = 1;
192 cpu->l = 0x4D;
193 cpu->sp = 0xFFFE;
194 cpu->pc = 0x100;
195
196 if (gb->yankedRomSize) {
197 gb->memory.romSize = gb->yankedRomSize;
198 gb->yankedRomSize = 0;
199 }
200 GBMemoryReset(gb);
201 GBVideoReset(&gb->video);
202 GBTimerReset(&gb->timer);
203 GBIOReset(gb);
204 GBAudioReset(&gb->audio);
205}
206
207void GBUpdateIRQs(struct GB* gb) {
208 int irqs = gb->memory.ie & gb->memory.io[REG_IF];
209 if (!irqs) {
210 return;
211 }
212 gb->cpu->halted = false;
213
214 if (!gb->memory.ime) {
215 return;
216 }
217
218 if (irqs & (1 << GB_IRQ_VBLANK)) {
219 LR35902RaiseIRQ(gb->cpu, GB_VECTOR_VBLANK);
220 gb->memory.io[REG_IF] &= ~(1 << GB_IRQ_VBLANK);
221 return;
222 }
223 if (irqs & (1 << GB_IRQ_LCDSTAT)) {
224 LR35902RaiseIRQ(gb->cpu, GB_VECTOR_LCDSTAT);
225 gb->memory.io[REG_IF] &= ~(1 << GB_IRQ_LCDSTAT);
226 return;
227 }
228 if (irqs & (1 << GB_IRQ_TIMER)) {
229 LR35902RaiseIRQ(gb->cpu, GB_VECTOR_TIMER);
230 gb->memory.io[REG_IF] &= ~(1 << GB_IRQ_TIMER);
231 return;
232 }
233 if (irqs & (1 << GB_IRQ_SIO)) {
234 LR35902RaiseIRQ(gb->cpu, GB_VECTOR_SIO);
235 gb->memory.io[REG_IF] &= ~(1 << GB_IRQ_SIO);
236 return;
237 }
238 if (irqs & (1 << GB_IRQ_KEYPAD)) {
239 LR35902RaiseIRQ(gb->cpu, GB_VECTOR_KEYPAD);
240 gb->memory.io[REG_IF] &= ~(1 << GB_IRQ_KEYPAD);
241 }
242}
243
244void GBProcessEvents(struct LR35902Core* cpu) {
245 struct GB* gb = (struct GB*) cpu->master;
246 do {
247 int32_t cycles = cpu->nextEvent;
248 int32_t nextEvent = INT_MAX;
249 int32_t testEvent;
250
251 if (gb->eiPending) {
252 gb->eiPending -= cycles;
253 if (gb->eiPending <= 0) {
254 gb->memory.ime = true;
255 GBUpdateIRQs(gb);
256 gb->eiPending = 0;
257 }
258 }
259
260 testEvent = GBVideoProcessEvents(&gb->video, cycles >> gb->doubleSpeed);
261 if (testEvent != INT_MAX) {
262 testEvent <<= gb->doubleSpeed;
263 if (testEvent < nextEvent) {
264 nextEvent = testEvent;
265 }
266 }
267
268 testEvent = GBAudioProcessEvents(&gb->audio, cycles >> gb->doubleSpeed);
269 if (testEvent != INT_MAX) {
270 testEvent <<= gb->doubleSpeed;
271 if (testEvent < nextEvent) {
272 nextEvent = testEvent;
273 }
274 }
275
276 testEvent = GBTimerProcessEvents(&gb->timer, cycles);
277 if (testEvent < nextEvent) {
278 nextEvent = testEvent;
279 }
280
281 testEvent = GBMemoryProcessEvents(gb, cycles);
282 if (testEvent < nextEvent) {
283 nextEvent = testEvent;
284 }
285
286 cpu->cycles -= cycles;
287 cpu->nextEvent = nextEvent;
288
289 if (cpu->halted) {
290 cpu->cycles = cpu->nextEvent;
291 }
292 } while (cpu->cycles >= cpu->nextEvent);
293}
294
295void GBSetInterrupts(struct LR35902Core* cpu, bool enable) {
296 struct GB* gb = (struct GB*) cpu->master;
297 if (!enable) {
298 gb->memory.ime = enable;
299 gb->eiPending = 0;
300 GBUpdateIRQs(gb);
301 } else {
302 if (cpu->nextEvent > cpu->cycles + 4) {
303 cpu->nextEvent = cpu->cycles + 4;
304 }
305 gb->eiPending = cpu->cycles + 4;
306 }
307}
308
309void GBHalt(struct LR35902Core* cpu) {
310 cpu->cycles = cpu->nextEvent;
311 cpu->halted = true;
312}
313
314void GBStop(struct LR35902Core* cpu) {
315 struct GB* gb = (struct GB*) cpu->master;
316 if (gb->memory.io[REG_KEY1] & 1) {
317 gb->doubleSpeed ^= 1;
318 gb->memory.io[REG_KEY1] &= 1;
319 gb->memory.io[REG_KEY1] |= gb->doubleSpeed << 7;
320 }
321 // TODO: Actually stop
322}
323
324void GBIllegal(struct LR35902Core* cpu) {
325 // TODO
326 mLOG(GB, GAME_ERROR, "Hit illegal opcode at address %04X:%02X\n", cpu->pc, cpu->bus);
327}
328
329bool GBIsROM(struct VFile* vf) {
330 vf->seek(vf, 0x104, SEEK_SET);
331 uint8_t header[4];
332 static const uint8_t knownHeader[4] = { 0xCE, 0xED, 0x66, 0x66};
333
334 if (vf->read(vf, &header, sizeof(header)) < (ssize_t) sizeof(header)) {
335 return false;
336 }
337 if (memcmp(header, knownHeader, sizeof(header))) {
338 return false;
339 }
340 return true;
341}
342
343void GBGetGameTitle(struct GB* gb, char* out) {
344 const struct GBCartridge* cart = NULL;
345 if (gb->memory.rom) {
346 cart = (const struct GBCartridge*) &gb->memory.rom[0x100];
347 }
348 if (gb->pristineRom) {
349 cart = (const struct GBCartridge*) &((uint8_t*) gb->pristineRom)[0x100];
350 }
351 if (!cart) {
352 return;
353 }
354 if (cart->oldLicensee != 0x33) {
355 memcpy(out, cart->titleLong, 16);
356 } else {
357 memcpy(out, cart->titleShort, 11);
358 }
359}
360
361void GBGetGameCode(struct GB* gb, char* out) {
362 memset(out, 0, 4);
363 const struct GBCartridge* cart = NULL;
364 if (gb->memory.rom) {
365 cart = (const struct GBCartridge*) &gb->memory.rom[0x100];
366 }
367 if (gb->pristineRom) {
368 cart = (const struct GBCartridge*) &((uint8_t*) gb->pristineRom)[0x100];
369 }
370 if (!cart) {
371 return;
372 }
373 if (cart->oldLicensee == 0x33) {
374 memcpy(out, cart->maker, 11);
375 }
376}