all repos — mgba @ 35906b51fd30b829fe3d53a31b0b488e7b570773

mGBA Game Boy Advance Emulator

src/gba/io.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/io.h>
  7
  8#include <mgba/internal/arm/macros.h>
  9#include <mgba/internal/gba/dma.h>
 10#include <mgba/internal/gba/gba.h>
 11#include <mgba/internal/gba/rr/rr.h>
 12#include <mgba/internal/gba/serialize.h>
 13
 14mLOG_DEFINE_CATEGORY(GBA_IO, "GBA I/O", "gba.io");
 15
 16const char* const GBAIORegisterNames[] = {
 17	// Video
 18	"DISPCNT",
 19	0,
 20	"DISPSTAT",
 21	"VCOUNT",
 22	"BG0CNT",
 23	"BG1CNT",
 24	"BG2CNT",
 25	"BG3CNT",
 26	"BG0HOFS",
 27	"BG0VOFS",
 28	"BG1HOFS",
 29	"BG1VOFS",
 30	"BG2HOFS",
 31	"BG2VOFS",
 32	"BG3HOFS",
 33	"BG3VOFS",
 34	"BG2PA",
 35	"BG2PB",
 36	"BG2PC",
 37	"BG2PD",
 38	"BG2X_LO",
 39	"BG2X_HI",
 40	"BG2Y_LO",
 41	"BG2Y_HI",
 42	"BG3PA",
 43	"BG3PB",
 44	"BG3PC",
 45	"BG3PD",
 46	"BG3X_LO",
 47	"BG3X_HI",
 48	"BG3Y_LO",
 49	"BG3Y_HI",
 50	"WIN0H",
 51	"WIN1H",
 52	"WIN0V",
 53	"WIN1V",
 54	"WININ",
 55	"WINOUT",
 56	"MOSAIC",
 57	0,
 58	"BLDCNT",
 59	"BLDALPHA",
 60	"BLDY",
 61	0,
 62	0,
 63	0,
 64	0,
 65	0,
 66
 67	// Sound
 68	"SOUND1CNT_LO",
 69	"SOUND1CNT_HI",
 70	"SOUND1CNT_X",
 71	0,
 72	"SOUND2CNT_LO",
 73	0,
 74	"SOUND2CNT_HI",
 75	0,
 76	"SOUND3CNT_LO",
 77	"SOUND3CNT_HI",
 78	"SOUND3CNT_X",
 79	0,
 80	"SOUND4CNT_LO",
 81	0,
 82	"SOUND4CNT_HI",
 83	0,
 84	"SOUNDCNT_LO",
 85	"SOUNDCNT_HI",
 86	"SOUNDCNT_X",
 87	0,
 88	"SOUNDBIAS",
 89	0,
 90	0,
 91	0,
 92	"WAVE_RAM0_LO",
 93	"WAVE_RAM0_HI",
 94	"WAVE_RAM1_LO",
 95	"WAVE_RAM1_HI",
 96	"WAVE_RAM2_LO",
 97	"WAVE_RAM2_HI",
 98	"WAVE_RAM3_LO",
 99	"WAVE_RAM3_HI",
100	"FIFO_A_LO",
101	"FIFO_A_HI",
102	"FIFO_B_LO",
103	"FIFO_B_HI",
104	0,
105	0,
106	0,
107	0,
108
109	// DMA
110	"DMA0SAD_LO",
111	"DMA0SAD_HI",
112	"DMA0DAD_LO",
113	"DMA0DAD_HI",
114	"DMA0CNT_LO",
115	"DMA0CNT_HI",
116	"DMA1SAD_LO",
117	"DMA1SAD_HI",
118	"DMA1DAD_LO",
119	"DMA1DAD_HI",
120	"DMA1CNT_LO",
121	"DMA1CNT_HI",
122	"DMA2SAD_LO",
123	"DMA2SAD_HI",
124	"DMA2DAD_LO",
125	"DMA2DAD_HI",
126	"DMA2CNT_LO",
127	"DMA2CNT_HI",
128	"DMA3SAD_LO",
129	"DMA3SAD_HI",
130	"DMA3DAD_LO",
131	"DMA3DAD_HI",
132	"DMA3CNT_LO",
133	"DMA3CNT_HI",
134
135	0, 0, 0, 0, 0, 0, 0, 0,
136	0, 0, 0, 0, 0, 0, 0, 0,
137
138	// Timers
139	"TM0CNT_LO",
140	"TM0CNT_HI",
141	"TM1CNT_LO",
142	"TM1CNT_HI",
143	"TM2CNT_LO",
144	"TM2CNT_HI",
145	"TM3CNT_LO",
146	"TM3CNT_HI",
147
148	0, 0, 0, 0, 0, 0, 0, 0,
149
150	// SIO
151	"SIOMULTI0",
152	"SIOMULTI1",
153	"SIOMULTI2",
154	"SIOMULTI3",
155	"SIOCNT",
156	"SIOMLT_SEND",
157	0,
158	0,
159	"KEYINPUT",
160	"KEYCNT",
161	"RCNT",
162	0,
163	0,
164	0,
165	0,
166	0,
167	"JOYCNT",
168	0,
169	0,
170	0,
171	0,
172	0,
173	0,
174	0,
175	"JOY_RECV_LO",
176	"JOY_RECV_HI",
177	"JOY_TRANS_LO",
178	"JOY_TRANS_HI",
179	"JOYSTAT",
180	0,
181	0,
182	0,
183
184	0, 0, 0, 0, 0, 0, 0, 0,
185	0, 0, 0, 0, 0, 0, 0, 0,
186	0, 0, 0, 0, 0, 0, 0, 0,
187	0, 0, 0, 0, 0, 0, 0, 0,
188	0, 0, 0, 0, 0, 0, 0, 0,
189	0, 0, 0, 0, 0, 0, 0, 0,
190	0, 0, 0, 0, 0, 0, 0, 0,
191	0, 0, 0, 0, 0, 0, 0, 0,
192	0, 0, 0, 0, 0, 0, 0, 0,
193	0, 0, 0, 0, 0, 0, 0, 0,
194
195	// Interrupts, etc
196	"IE",
197	"IF",
198	"WAITCNT",
199	0,
200	"IME"
201};
202
203static const int _isValidRegister[REG_MAX >> 1] = {
204	// Video
205	1, 0, 1, 1, 1, 1, 1, 1,
206	1, 1, 1, 1, 1, 1, 1, 1,
207	1, 1, 1, 1, 1, 1, 1, 1,
208	1, 1, 1, 1, 1, 1, 1, 1,
209	1, 1, 1, 1, 1, 1, 1, 0,
210	1, 1, 1, 0, 0, 0, 0, 0,
211	// Audio
212	1, 1, 1, 0, 1, 0, 1, 0,
213	1, 1, 1, 0, 1, 0, 1, 0,
214	1, 1, 1, 0, 1, 0, 0, 0,
215	1, 1, 1, 1, 1, 1, 1, 1,
216	1, 1, 1, 1, 0, 0, 0, 0,
217	// DMA
218	1, 1, 1, 1, 1, 1, 1, 1,
219	1, 1, 1, 1, 1, 1, 1, 1,
220	1, 1, 1, 1, 1, 1, 1, 1,
221	0, 0, 0, 0, 0, 0, 0, 0,
222	0, 0, 0, 0, 0, 0, 0, 0,
223	// Timers
224	1, 1, 1, 1, 1, 1, 1, 1,
225	0, 0, 0, 0, 0, 0, 0, 0,
226	// SIO
227	1, 1, 1, 1, 1, 0, 0, 0,
228	1, 1, 1, 0, 0, 0, 0, 0,
229	1, 0, 0, 0, 0, 0, 0, 0,
230	1, 0, 1, 0, 1, 0, 0, 0,
231	0, 0, 0, 0, 0, 0, 0, 0,
232	0, 0, 0, 0, 0, 0, 0, 0,
233	0, 0, 0, 0, 0, 0, 0, 0,
234	0, 0, 0, 0, 0, 0, 0, 0,
235	0, 0, 0, 0, 0, 0, 0, 0,
236	0, 0, 0, 0, 0, 0, 0, 0,
237	0, 0, 0, 0, 0, 0, 0, 0,
238	0, 0, 0, 0, 0, 0, 0, 0,
239	0, 0, 0, 0, 0, 0, 0, 0,
240	0, 0, 0, 0, 0, 0, 0, 0,
241	// Interrupts
242	1, 1, 1, 0, 1
243};
244
245static const int _isRSpecialRegister[REG_MAX >> 1] = {
246	// Video
247	0, 0, 1, 1, 0, 0, 0, 0,
248	1, 1, 1, 1, 1, 1, 1, 1,
249	1, 1, 1, 1, 1, 1, 1, 1,
250	1, 1, 1, 1, 1, 1, 1, 1,
251	1, 1, 1, 1, 1, 1, 1, 1,
252	1, 1, 1, 1, 1, 1, 1, 1,
253	// Audio
254	0, 0, 1, 0, 0, 0, 1, 0,
255	0, 0, 1, 0, 0, 0, 1, 0,
256	0, 0, 0, 0, 1, 0, 0, 0,
257	1, 1, 1, 1, 1, 1, 1, 1,
258	1, 1, 1, 1, 0, 0, 0, 0,
259	// DMA
260	1, 1, 1, 1, 1, 1, 1, 1,
261	1, 1, 1, 1, 1, 1, 1, 1,
262	1, 1, 1, 1, 1, 1, 1, 1,
263	0, 0, 0, 0, 0, 0, 0, 0,
264	0, 0, 0, 0, 0, 0, 0, 0,
265	// Timers
266	1, 1, 1, 1, 1, 1, 1, 1,
267	0, 0, 0, 0, 0, 0, 0, 0,
268	// SIO
269	1, 1, 1, 1, 1, 0, 0, 0,
270	1, 1, 1, 0, 0, 0, 0, 0,
271	1, 0, 0, 0, 0, 0, 0, 0,
272	1, 0, 1, 0, 1, 0, 0, 0,
273	0, 0, 0, 0, 0, 0, 0, 0,
274	0, 0, 0, 0, 0, 0, 0, 0,
275	0, 0, 0, 0, 0, 0, 0, 0,
276	0, 0, 0, 0, 0, 0, 0, 0,
277	0, 0, 0, 0, 0, 0, 0, 0,
278	0, 0, 0, 0, 0, 0, 0, 0,
279	0, 0, 0, 0, 0, 0, 0, 0,
280	0, 0, 0, 0, 0, 0, 0, 0,
281	0, 0, 0, 0, 0, 0, 0, 0,
282	0, 0, 0, 0, 0, 0, 0, 0,
283	// Interrupts
284};
285
286static const int _isWSpecialRegister[REG_MAX >> 1] = {
287	// Video
288	0, 0, 1, 1, 0, 0, 0, 0,
289	0, 0, 0, 0, 0, 0, 0, 0,
290	0, 0, 0, 0, 0, 0, 0, 0,
291	0, 0, 0, 0, 0, 0, 0, 0,
292	0, 0, 0, 0, 0, 0, 0, 0,
293	0, 0, 0, 0, 0, 0, 0, 0,
294	// Audio
295	1, 1, 1, 0, 1, 0, 1, 0,
296	1, 1, 1, 0, 1, 0, 1, 0,
297	1, 0, 1, 0, 0, 0, 0, 0,
298	1, 1, 1, 1, 1, 1, 1, 1,
299	1, 1, 1, 1, 0, 0, 0, 0,
300	// DMA
301	0, 0, 0, 0, 0, 1, 0, 0,
302	0, 0, 0, 1, 0, 0, 0, 0,
303	0, 1, 0, 0, 0, 0, 0, 1,
304	0, 0, 0, 0, 0, 0, 0, 0,
305	0, 0, 0, 0, 0, 0, 0, 0,
306	// Timers
307	1, 1, 1, 1, 1, 1, 1, 1,
308	0, 0, 0, 0, 0, 0, 0, 0,
309	// SIO
310	1, 1, 1, 1, 1, 0, 0, 0,
311	1, 1, 1, 0, 0, 0, 0, 0,
312	1, 0, 0, 0, 0, 0, 0, 0,
313	1, 0, 1, 0, 1, 0, 0, 0,
314	0, 0, 0, 0, 0, 0, 0, 0,
315	0, 0, 0, 0, 0, 0, 0, 0,
316	0, 0, 0, 0, 0, 0, 0, 0,
317	0, 0, 0, 0, 0, 0, 0, 0,
318	0, 0, 0, 0, 0, 0, 0, 0,
319	0, 0, 0, 0, 0, 0, 0, 0,
320	0, 0, 0, 0, 0, 0, 0, 0,
321	0, 0, 0, 0, 0, 0, 0, 0,
322	0, 0, 0, 0, 0, 0, 0, 0,
323	0, 0, 0, 0, 0, 0, 0, 0,
324	// Interrupts
325	1, 1, 0, 0, 1
326};
327
328void GBAIOInit(struct GBA* gba) {
329	gba->memory.io[REG_DISPCNT >> 1] = 0x0080;
330	gba->memory.io[REG_RCNT >> 1] = RCNT_INITIAL;
331	gba->memory.io[REG_KEYINPUT >> 1] = 0x3FF;
332	gba->memory.io[REG_SOUNDBIAS >> 1] = 0x200;
333	gba->memory.io[REG_BG2PA >> 1] = 0x100;
334	gba->memory.io[REG_BG2PD >> 1] = 0x100;
335	gba->memory.io[REG_BG3PA >> 1] = 0x100;
336	gba->memory.io[REG_BG3PD >> 1] = 0x100;
337
338	if (!gba->biosVf) {
339		gba->memory.io[REG_VCOUNT >> 1] = 0x7E;
340		gba->memory.io[REG_POSTFLG >> 1] = 1;
341	}
342}
343
344void GBAIOWrite(struct GBA* gba, uint32_t address, uint16_t value) {
345	if (address < REG_SOUND1CNT_LO && (address > REG_VCOUNT || address == REG_DISPCNT)) {
346		value = gba->video.renderer->writeVideoRegister(gba->video.renderer, address, value);
347	} else {
348		switch (address) {
349		// Video
350		case REG_DISPSTAT:
351			value &= 0xFFF8;
352			GBAVideoWriteDISPSTAT(&gba->video, value);
353			return;
354
355		case REG_VCOUNT:
356			mLOG(GBA_IO, GAME_ERROR, "Write to read-only I/O register: %03X", address);
357			return;
358
359		// Audio
360		case REG_SOUND1CNT_LO:
361			GBAAudioWriteSOUND1CNT_LO(&gba->audio, value);
362			value &= 0x007F;
363			break;
364		case REG_SOUND1CNT_HI:
365			GBAAudioWriteSOUND1CNT_HI(&gba->audio, value);
366			break;
367		case REG_SOUND1CNT_X:
368			GBAAudioWriteSOUND1CNT_X(&gba->audio, value);
369			value &= 0x47FF;
370			break;
371		case REG_SOUND2CNT_LO:
372			GBAAudioWriteSOUND2CNT_LO(&gba->audio, value);
373			break;
374		case REG_SOUND2CNT_HI:
375			GBAAudioWriteSOUND2CNT_HI(&gba->audio, value);
376			value &= 0x47FF;
377			break;
378		case REG_SOUND3CNT_LO:
379			GBAAudioWriteSOUND3CNT_LO(&gba->audio, value);
380			value &= 0x00E0;
381			break;
382		case REG_SOUND3CNT_HI:
383			GBAAudioWriteSOUND3CNT_HI(&gba->audio, value);
384			value &= 0xE03F;
385			break;
386		case REG_SOUND3CNT_X:
387			GBAAudioWriteSOUND3CNT_X(&gba->audio, value);
388			// TODO: The low bits need to not be readable, but still 8-bit writable
389			value &= 0x47FF;
390			break;
391		case REG_SOUND4CNT_LO:
392			GBAAudioWriteSOUND4CNT_LO(&gba->audio, value);
393			value &= 0xFF3F;
394			break;
395		case REG_SOUND4CNT_HI:
396			GBAAudioWriteSOUND4CNT_HI(&gba->audio, value);
397			value &= 0x40FF;
398			break;
399		case REG_SOUNDCNT_LO:
400			GBAAudioWriteSOUNDCNT_LO(&gba->audio, value);
401			value &= 0xFF77;
402			break;
403		case REG_SOUNDCNT_HI:
404			GBAAudioWriteSOUNDCNT_HI(&gba->audio, value);
405			value &= 0x770F;
406			break;
407		case REG_SOUNDCNT_X:
408			GBAAudioWriteSOUNDCNT_X(&gba->audio, value);
409			value &= 0x0080;
410			value |= gba->memory.io[REG_SOUNDCNT_X >> 1] & 0xF;
411			break;
412		case REG_SOUNDBIAS:
413			GBAAudioWriteSOUNDBIAS(&gba->audio, value);
414			break;
415
416		case REG_WAVE_RAM0_LO:
417		case REG_WAVE_RAM1_LO:
418		case REG_WAVE_RAM2_LO:
419		case REG_WAVE_RAM3_LO:
420			GBAIOWrite32(gba, address, (gba->memory.io[(address >> 1) + 1] << 16) | value);
421			break;
422
423		case REG_WAVE_RAM0_HI:
424		case REG_WAVE_RAM1_HI:
425		case REG_WAVE_RAM2_HI:
426		case REG_WAVE_RAM3_HI:
427			GBAIOWrite32(gba, address - 2, gba->memory.io[(address >> 1) - 1] | (value << 16));
428			break;
429
430		case REG_FIFO_A_LO:
431		case REG_FIFO_B_LO:
432			GBAIOWrite32(gba, address, (gba->memory.io[(address >> 1) + 1] << 16) | value);
433			break;
434
435		case REG_FIFO_A_HI:
436		case REG_FIFO_B_HI:
437			GBAIOWrite32(gba, address - 2, gba->memory.io[(address >> 1) - 1] | (value << 16));
438			break;
439
440		// DMA
441		case REG_DMA0SAD_LO:
442		case REG_DMA0DAD_LO:
443		case REG_DMA1SAD_LO:
444		case REG_DMA1DAD_LO:
445		case REG_DMA2SAD_LO:
446		case REG_DMA2DAD_LO:
447		case REG_DMA3SAD_LO:
448		case REG_DMA3DAD_LO:
449			GBAIOWrite32(gba, address, (gba->memory.io[(address >> 1) + 1] << 16) | value);
450			break;
451
452		case REG_DMA0SAD_HI:
453		case REG_DMA0DAD_HI:
454		case REG_DMA1SAD_HI:
455		case REG_DMA1DAD_HI:
456		case REG_DMA2SAD_HI:
457		case REG_DMA2DAD_HI:
458		case REG_DMA3SAD_HI:
459		case REG_DMA3DAD_HI:
460			GBAIOWrite32(gba, address - 2, gba->memory.io[(address >> 1) - 1] | (value << 16));
461			break;
462
463		case REG_DMA0CNT_LO:
464			GBADMAWriteCNT_LO(gba, 0, value);
465			break;
466		case REG_DMA0CNT_HI:
467			value = GBADMAWriteCNT_HI(gba, 0, value);
468			break;
469		case REG_DMA1CNT_LO:
470			GBADMAWriteCNT_LO(gba, 1, value);
471			break;
472		case REG_DMA1CNT_HI:
473			value = GBADMAWriteCNT_HI(gba, 1, value);
474			break;
475		case REG_DMA2CNT_LO:
476			GBADMAWriteCNT_LO(gba, 2, value);
477			break;
478		case REG_DMA2CNT_HI:
479			value = GBADMAWriteCNT_HI(gba, 2, value);
480			break;
481		case REG_DMA3CNT_LO:
482			GBADMAWriteCNT_LO(gba, 3, value);
483			break;
484		case REG_DMA3CNT_HI:
485			value = GBADMAWriteCNT_HI(gba, 3, value);
486			break;
487
488		// Timers
489		case REG_TM0CNT_LO:
490			GBATimerWriteTMCNT_LO(gba, 0, value);
491			return;
492		case REG_TM1CNT_LO:
493			GBATimerWriteTMCNT_LO(gba, 1, value);
494			return;
495		case REG_TM2CNT_LO:
496			GBATimerWriteTMCNT_LO(gba, 2, value);
497			return;
498		case REG_TM3CNT_LO:
499			GBATimerWriteTMCNT_LO(gba, 3, value);
500			return;
501
502		case REG_TM0CNT_HI:
503			value &= 0x00C7;
504			GBATimerWriteTMCNT_HI(gba, 0, value);
505			break;
506		case REG_TM1CNT_HI:
507			value &= 0x00C7;
508			GBATimerWriteTMCNT_HI(gba, 1, value);
509			break;
510		case REG_TM2CNT_HI:
511			value &= 0x00C7;
512			GBATimerWriteTMCNT_HI(gba, 2, value);
513			break;
514		case REG_TM3CNT_HI:
515			value &= 0x00C7;
516			GBATimerWriteTMCNT_HI(gba, 3, value);
517			break;
518
519		// SIO
520		case REG_SIOCNT:
521			GBASIOWriteSIOCNT(&gba->sio, value);
522			break;
523		case REG_RCNT:
524			value &= 0xC1FF;
525			GBASIOWriteRCNT(&gba->sio, value);
526			break;
527		case REG_JOY_TRANS_LO:
528		case REG_JOY_TRANS_HI:
529			gba->memory.io[REG_JOYSTAT >> 1] |= JOYSTAT_TRANS_BIT;
530			// Fall through
531		case REG_SIOMLT_SEND:
532		case REG_JOYCNT:
533		case REG_JOYSTAT:
534		case REG_JOY_RECV_LO:
535		case REG_JOY_RECV_HI:
536			value = GBASIOWriteRegister(&gba->sio, address, value);
537			break;
538
539		// Interrupts and misc
540		case REG_KEYCNT:
541			value &= 0xC3FF;
542			gba->memory.io[address >> 1] = value;
543			GBATestKeypadIRQ(gba);
544			return;
545		case REG_WAITCNT:
546			value &= 0x5FFF;
547			GBAAdjustWaitstates(gba, value);
548			break;
549		case REG_IE:
550			GBAWriteIE(gba, value);
551			break;
552		case REG_IF:
553			gba->springIRQ &= ~value;
554			value = gba->memory.io[REG_IF >> 1] & ~value;
555			break;
556		case REG_IME:
557			GBAWriteIME(gba, value);
558			break;
559		case REG_MAX:
560			// Some bad interrupt libraries will write to this
561			break;
562		case REG_DEBUG_ENABLE:
563			gba->debug = value == 0xC0DE;
564			return;
565		case REG_DEBUG_FLAGS:
566			if (gba->debug) {
567				GBADebug(gba, value);
568				return;
569			}
570			// Fall through
571		default:
572			if (address >= REG_DEBUG_STRING && address - REG_DEBUG_STRING < sizeof(gba->debugString)) {
573				STORE_16LE(value, address - REG_DEBUG_STRING, gba->debugString);
574				return;
575			}
576			mLOG(GBA_IO, STUB, "Stub I/O register write: %03X", address);
577			if (address >= REG_MAX) {
578				mLOG(GBA_IO, GAME_ERROR, "Write to unused I/O register: %03X", address);
579				return;
580			}
581			break;
582		}
583	}
584	gba->memory.io[address >> 1] = value;
585}
586
587void GBAIOWrite8(struct GBA* gba, uint32_t address, uint8_t value) {
588	if (address == REG_HALTCNT) {
589		value &= 0x80;
590		if (!value) {
591			GBAHalt(gba);
592		} else {
593			GBAStop(gba);
594		}
595		return;
596	}
597	if (address == REG_POSTFLG) {
598		gba->memory.io[(address & (SIZE_IO - 1)) >> 1] = value;
599		return;
600	}
601	if (address >= REG_DEBUG_STRING && address - REG_DEBUG_STRING < sizeof(gba->debugString)) {
602		gba->debugString[address - REG_DEBUG_STRING] = value;
603		return;
604	}
605	if (address > SIZE_IO) {
606		return;
607	}
608	uint16_t value16 = value << (8 * (address & 1));
609	value16 |= (gba->memory.io[(address & (SIZE_IO - 1)) >> 1]) & ~(0xFF << (8 * (address & 1)));
610	GBAIOWrite(gba, address & 0xFFFFFFFE, value16);
611}
612
613void GBAIOWrite32(struct GBA* gba, uint32_t address, uint32_t value) {
614	switch (address) {
615	case REG_WAVE_RAM0_LO:
616		GBAAudioWriteWaveRAM(&gba->audio, 0, value);
617		break;
618	case REG_WAVE_RAM1_LO:
619		GBAAudioWriteWaveRAM(&gba->audio, 1, value);
620		break;
621	case REG_WAVE_RAM2_LO:
622		GBAAudioWriteWaveRAM(&gba->audio, 2, value);
623		break;
624	case REG_WAVE_RAM3_LO:
625		GBAAudioWriteWaveRAM(&gba->audio, 3, value);
626		break;
627	case REG_FIFO_A_LO:
628	case REG_FIFO_B_LO:
629		GBAAudioWriteFIFO(&gba->audio, address, value);
630		break;
631	case REG_DMA0SAD_LO:
632		value = GBADMAWriteSAD(gba, 0, value);
633		break;
634	case REG_DMA0DAD_LO:
635		value = GBADMAWriteDAD(gba, 0, value);
636		break;
637	case REG_DMA1SAD_LO:
638		value = GBADMAWriteSAD(gba, 1, value);
639		break;
640	case REG_DMA1DAD_LO:
641		value = GBADMAWriteDAD(gba, 1, value);
642		break;
643	case REG_DMA2SAD_LO:
644		value = GBADMAWriteSAD(gba, 2, value);
645		break;
646	case REG_DMA2DAD_LO:
647		value = GBADMAWriteDAD(gba, 2, value);
648		break;
649	case REG_DMA3SAD_LO:
650		value = GBADMAWriteSAD(gba, 3, value);
651		break;
652	case REG_DMA3DAD_LO:
653		value = GBADMAWriteDAD(gba, 3, value);
654		break;
655	default:
656		if (address >= REG_DEBUG_STRING && address - REG_DEBUG_STRING < sizeof(gba->debugString)) {
657			STORE_32LE(value, address - REG_DEBUG_STRING, gba->debugString);
658			return;
659		}
660		GBAIOWrite(gba, address, value & 0xFFFF);
661		GBAIOWrite(gba, address | 2, value >> 16);
662		return;
663	}
664	gba->memory.io[address >> 1] = value;
665	gba->memory.io[(address >> 1) + 1] = value >> 16;
666}
667
668bool GBAIOIsReadConstant(uint32_t address) {
669	switch (address) {
670	default:
671		return false;
672	case REG_BG0CNT:
673	case REG_BG1CNT:
674	case REG_BG2CNT:
675	case REG_BG3CNT:
676	case REG_WININ:
677	case REG_WINOUT:
678	case REG_BLDCNT:
679	case REG_BLDALPHA:
680	case REG_SOUND1CNT_LO:
681	case REG_SOUND1CNT_HI:
682	case REG_SOUND1CNT_X:
683	case REG_SOUND2CNT_LO:
684	case REG_SOUND2CNT_HI:
685	case REG_SOUND3CNT_LO:
686	case REG_SOUND3CNT_HI:
687	case REG_SOUND3CNT_X:
688	case REG_SOUND4CNT_LO:
689	case REG_SOUND4CNT_HI:
690	case REG_SOUNDCNT_LO:
691	case REG_SOUNDCNT_HI:
692	case REG_TM0CNT_HI:
693	case REG_TM1CNT_HI:
694	case REG_TM2CNT_HI:
695	case REG_TM3CNT_HI:
696	case REG_KEYINPUT:
697	case REG_KEYCNT:
698	case REG_IE:
699		return true;
700	}
701}
702
703uint16_t GBAIORead(struct GBA* gba, uint32_t address) {
704	if (!GBAIOIsReadConstant(address)) {
705		// Most IO reads need to disable idle removal
706		gba->haltPending = false;
707	}
708
709	switch (address) {
710	case REG_TM0CNT_LO:
711		GBATimerUpdateRegister(gba, 0);
712		break;
713	case REG_TM1CNT_LO:
714		GBATimerUpdateRegister(gba, 1);
715		break;
716	case REG_TM2CNT_LO:
717		GBATimerUpdateRegister(gba, 2);
718		break;
719	case REG_TM3CNT_LO:
720		GBATimerUpdateRegister(gba, 3);
721		break;
722
723	case REG_KEYINPUT:
724		if (gba->rr && gba->rr->isPlaying(gba->rr)) {
725			return 0x3FF ^ gba->rr->queryInput(gba->rr);
726		} else {
727			uint16_t input = 0x3FF;
728			if (gba->keyCallback) {
729				input = gba->keyCallback->readKeys(gba->keyCallback);
730				if (gba->keySource) {
731					*gba->keySource = input;
732				}
733			} else if (gba->keySource) {
734				input = *gba->keySource;
735			}
736			if (!gba->allowOpposingDirections) {
737				unsigned rl = input & 0x030;
738				unsigned ud = input & 0x0C0;
739				input &= 0x30F;
740				if (rl != 0x030) {
741					input |= rl;
742				}
743				if (ud != 0x0C0) {
744					input |= ud;
745				}
746			}
747			if (gba->rr && gba->rr->isRecording(gba->rr)) {
748				gba->rr->logInput(gba->rr, input);
749			}
750			return 0x3FF ^ input;
751		}
752
753	case REG_SIOCNT:
754		return gba->sio.siocnt;
755	case REG_RCNT:
756		return gba->sio.rcnt;
757
758	case REG_BG0HOFS:
759	case REG_BG0VOFS:
760	case REG_BG1HOFS:
761	case REG_BG1VOFS:
762	case REG_BG2HOFS:
763	case REG_BG2VOFS:
764	case REG_BG3HOFS:
765	case REG_BG3VOFS:
766	case REG_BG2PA:
767	case REG_BG2PB:
768	case REG_BG2PC:
769	case REG_BG2PD:
770	case REG_BG2X_LO:
771	case REG_BG2X_HI:
772	case REG_BG2Y_LO:
773	case REG_BG2Y_HI:
774	case REG_BG3PA:
775	case REG_BG3PB:
776	case REG_BG3PC:
777	case REG_BG3PD:
778	case REG_BG3X_LO:
779	case REG_BG3X_HI:
780	case REG_BG3Y_LO:
781	case REG_BG3Y_HI:
782	case REG_WIN0H:
783	case REG_WIN1H:
784	case REG_WIN0V:
785	case REG_WIN1V:
786	case REG_MOSAIC:
787	case REG_BLDY:
788	case REG_FIFO_A_LO:
789	case REG_FIFO_A_HI:
790	case REG_FIFO_B_LO:
791	case REG_FIFO_B_HI:
792	case REG_DMA0SAD_LO:
793	case REG_DMA0SAD_HI:
794	case REG_DMA0DAD_LO:
795	case REG_DMA0DAD_HI:
796	case REG_DMA1SAD_LO:
797	case REG_DMA1SAD_HI:
798	case REG_DMA1DAD_LO:
799	case REG_DMA1DAD_HI:
800	case REG_DMA2SAD_LO:
801	case REG_DMA2SAD_HI:
802	case REG_DMA2DAD_LO:
803	case REG_DMA2DAD_HI:
804	case REG_DMA3SAD_LO:
805	case REG_DMA3SAD_HI:
806	case REG_DMA3DAD_LO:
807	case REG_DMA3DAD_HI:
808		// Write-only register
809		mLOG(GBA_IO, GAME_ERROR, "Read from write-only I/O register: %03X", address);
810		return GBALoadBad(gba->cpu);
811
812	case REG_DMA0CNT_LO:
813	case REG_DMA1CNT_LO:
814	case REG_DMA2CNT_LO:
815	case REG_DMA3CNT_LO:
816		// Write-only register
817		mLOG(GBA_IO, GAME_ERROR, "Read from write-only I/O register: %03X", address);
818		return 0;
819
820	case REG_JOY_RECV_LO:
821	case REG_JOY_RECV_HI:
822		gba->memory.io[REG_JOYSTAT >> 1] &= ~JOYSTAT_RECV_BIT;
823		break;
824
825	case REG_SOUNDBIAS:
826	case REG_POSTFLG:
827		mLOG(GBA_IO, STUB, "Stub I/O register read: %03x", address);
828		break;
829	case REG_SOUND1CNT_LO:
830	case REG_SOUND1CNT_HI:
831	case REG_SOUND1CNT_X:
832	case REG_SOUND2CNT_LO:
833	case REG_SOUND2CNT_HI:
834	case REG_SOUND3CNT_LO:
835	case REG_SOUND3CNT_HI:
836	case REG_SOUND3CNT_X:
837	case REG_SOUND4CNT_LO:
838	case REG_SOUND4CNT_HI:
839	case REG_SOUNDCNT_LO:
840	case REG_SOUNDCNT_HI:
841		if (!GBAudioEnableIsEnable(gba->memory.io[REG_SOUNDCNT_X >> 1])) {
842			// TODO: Is writing allowed when the circuit is disabled?
843			return 0;
844		}
845		// Fall through
846	case REG_DISPCNT:
847	case REG_DISPSTAT:
848	case REG_VCOUNT:
849	case REG_BG0CNT:
850	case REG_BG1CNT:
851	case REG_BG2CNT:
852	case REG_BG3CNT:
853	case REG_WININ:
854	case REG_WINOUT:
855	case REG_BLDCNT:
856	case REG_BLDALPHA:
857	case REG_SOUNDCNT_X:
858	case REG_WAVE_RAM0_LO:
859	case REG_WAVE_RAM0_HI:
860	case REG_WAVE_RAM1_LO:
861	case REG_WAVE_RAM1_HI:
862	case REG_WAVE_RAM2_LO:
863	case REG_WAVE_RAM2_HI:
864	case REG_WAVE_RAM3_LO:
865	case REG_WAVE_RAM3_HI:
866	case REG_DMA0CNT_HI:
867	case REG_DMA1CNT_HI:
868	case REG_DMA2CNT_HI:
869	case REG_DMA3CNT_HI:
870	case REG_TM0CNT_HI:
871	case REG_TM1CNT_HI:
872	case REG_TM2CNT_HI:
873	case REG_TM3CNT_HI:
874	case REG_KEYCNT:
875	case REG_SIOMULTI0:
876	case REG_SIOMULTI1:
877	case REG_SIOMULTI2:
878	case REG_SIOMULTI3:
879	case REG_SIOMLT_SEND:
880	case REG_JOYCNT:
881	case REG_JOY_TRANS_LO:
882	case REG_JOY_TRANS_HI:
883	case REG_JOYSTAT:
884	case REG_IE:
885	case REG_IF:
886	case REG_WAITCNT:
887	case REG_IME:
888		// Handled transparently by registers
889		break;
890	case REG_MAX:
891		// Some bad interrupt libraries will read from this
892		break;
893	case 0x66:
894	case 0x6E:
895	case 0x76:
896	case 0x7A:
897	case 0x7E:
898	case 0x86:
899	case 0x8A:
900		mLOG(GBA_IO, GAME_ERROR, "Read from unused I/O register: %03X", address);
901		return 0;
902	case REG_DEBUG_ENABLE:
903		if (gba->debug) {
904			return 0x1DEA;
905		}
906		// Fall through
907	default:
908		mLOG(GBA_IO, GAME_ERROR, "Read from unused I/O register: %03X", address);
909		return GBALoadBad(gba->cpu);
910	}
911	return gba->memory.io[address >> 1];
912}
913
914void GBAIOSerialize(struct GBA* gba, struct GBASerializedState* state) {
915	int i;
916	for (i = 0; i < REG_MAX; i += 2) {
917		if (_isRSpecialRegister[i >> 1]) {
918			STORE_16(gba->memory.io[i >> 1], i, state->io);
919		} else if (_isValidRegister[i >> 1]) {
920			uint16_t reg = GBAIORead(gba, i);
921			STORE_16(reg, i, state->io);
922		}
923	}
924
925	for (i = 0; i < 4; ++i) {
926		STORE_16(gba->memory.io[(REG_DMA0CNT_LO + i * 12) >> 1], (REG_DMA0CNT_LO + i * 12), state->io);
927		STORE_16(gba->timers[i].reload, 0, &state->timers[i].reload);
928		STORE_16(gba->timers[i].oldReload, 0, &state->timers[i].oldReload);
929		STORE_32(gba->timers[i].lastEvent - mTimingCurrentTime(&gba->timing), 0, &state->timers[i].lastEvent);
930		STORE_32(gba->timers[i].event.when - mTimingCurrentTime(&gba->timing), 0, &state->timers[i].nextEvent);
931		STORE_32(gba->timers[i].overflowInterval, 0, &state->timers[i].overflowInterval);
932		STORE_32(gba->timers[i].flags, 0, &state->timers[i].flags);
933		STORE_32(gba->memory.dma[i].nextSource, 0, &state->dma[i].nextSource);
934		STORE_32(gba->memory.dma[i].nextDest, 0, &state->dma[i].nextDest);
935		STORE_32(gba->memory.dma[i].nextCount, 0, &state->dma[i].nextCount);
936		STORE_32(gba->memory.dma[i].when, 0, &state->dma[i].when);
937	}
938
939	GBAHardwareSerialize(&gba->memory.hw, state);
940}
941
942void GBAIODeserialize(struct GBA* gba, const struct GBASerializedState* state) {
943	int i;
944	for (i = 0; i < REG_MAX; i += 2) {
945		if (_isWSpecialRegister[i >> 1]) {
946			LOAD_16(gba->memory.io[i >> 1], i, state->io);
947		} else if (_isValidRegister[i >> 1]) {
948			uint16_t reg;
949			LOAD_16(reg, i, state->io);
950			GBAIOWrite(gba, i, reg);
951		}
952	}
953
954	uint32_t when;
955	for (i = 0; i < 4; ++i) {
956		LOAD_16(gba->timers[i].reload, 0, &state->timers[i].reload);
957		LOAD_16(gba->timers[i].oldReload, 0, &state->timers[i].oldReload);
958		LOAD_32(gba->timers[i].overflowInterval, 0, &state->timers[i].overflowInterval);
959		LOAD_32(gba->timers[i].flags, 0, &state->timers[i].flags);
960		if (i > 0 && GBATimerFlagsIsCountUp(gba->timers[i].flags)) {
961			// Overwrite invalid values in savestate
962			gba->timers[i].lastEvent = 0;
963		} else {
964			LOAD_32(when, 0, &state->timers[i].lastEvent);
965			gba->timers[i].lastEvent = when + mTimingCurrentTime(&gba->timing);
966		}
967		LOAD_32(when, 0, &state->timers[i].nextEvent);
968		if (GBATimerFlagsIsEnable(gba->timers[i].flags)) {
969			mTimingSchedule(&gba->timing, &gba->timers[i].event, when);
970		}
971
972		LOAD_16(gba->memory.dma[i].reg, (REG_DMA0CNT_HI + i * 12), state->io);
973		LOAD_32(gba->memory.dma[i].nextSource, 0, &state->dma[i].nextSource);
974		LOAD_32(gba->memory.dma[i].nextDest, 0, &state->dma[i].nextDest);
975		LOAD_32(gba->memory.dma[i].nextCount, 0, &state->dma[i].nextCount);
976		LOAD_32(gba->memory.dma[i].when, 0, &state->dma[i].when);
977		if (GBADMARegisterGetTiming(gba->memory.dma[i].reg) != DMA_TIMING_NOW) {
978			GBADMASchedule(gba, i, &gba->memory.dma[i]);
979		}
980	}
981	GBAAudioWriteSOUNDCNT_X(&gba->audio, gba->memory.io[REG_SOUNDCNT_X >> 1]);
982	GBADMAUpdate(gba);
983	GBAHardwareDeserialize(&gba->memory.hw, state);
984}