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