all repos — mgba @ e1b57de0356ab19713d3b6c8d77bf2e6e267c66d

mGBA Game Boy Advance Emulator

src/gba/bios.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/bios.h>
  7
  8#include <mgba/internal/arm/isa-inlines.h>
  9#include <mgba/internal/arm/macros.h>
 10#include <mgba/internal/gba/gba.h>
 11#include <mgba/internal/gba/io.h>
 12#include <mgba/internal/gba/memory.h>
 13#include <mgba-util/math.h>
 14
 15const uint32_t GBA_BIOS_CHECKSUM = 0xBAAE187F;
 16const uint32_t GBA_DS_BIOS_CHECKSUM = 0xBAAE1880;
 17
 18mLOG_DEFINE_CATEGORY(GBA_BIOS, "GBA BIOS", "gba.bios");
 19
 20static void _unLz77(struct GBA* gba, int width);
 21static void _unHuffman(struct GBA* gba);
 22static void _unRl(struct GBA* gba, int width);
 23static void _unFilter(struct GBA* gba, int inwidth, int outwidth);
 24static void _unBitPack(struct GBA* gba);
 25
 26static int _mulWait(int32_t r) {
 27	if ((r & 0xFFFFFF00) == 0xFFFFFF00 || !(r & 0xFFFFFF00)) {
 28		return 1;
 29	} else if ((r & 0xFFFF0000) == 0xFFFF0000 || !(r & 0xFFFF0000)) {
 30		return 2;
 31	} else if ((r & 0xFF000000) == 0xFF000000 || !(r & 0xFF000000)) {
 32		return 3;
 33	} else {
 34		return 4;
 35	}
 36}
 37
 38static void _SoftReset(struct GBA* gba) {
 39	struct ARMCore* cpu = gba->cpu;
 40	ARMSetPrivilegeMode(cpu, MODE_IRQ);
 41	cpu->spsr.packed = 0;
 42	cpu->gprs[ARM_LR] = 0;
 43	cpu->gprs[ARM_SP] = SP_BASE_IRQ;
 44	ARMSetPrivilegeMode(cpu, MODE_SUPERVISOR);
 45	cpu->spsr.packed = 0;
 46	cpu->gprs[ARM_LR] = 0;
 47	cpu->gprs[ARM_SP] = SP_BASE_SUPERVISOR;
 48	ARMSetPrivilegeMode(cpu, MODE_SYSTEM);
 49	cpu->gprs[ARM_LR] = 0;
 50	cpu->gprs[ARM_SP] = SP_BASE_SYSTEM;
 51	int8_t flag = ((int8_t*) gba->memory.iwram)[0x7FFA];
 52	memset(((int8_t*) gba->memory.iwram) + SIZE_WORKING_IRAM - 0x200, 0, 0x200);
 53	if (flag) {
 54		cpu->gprs[ARM_PC] = BASE_WORKING_RAM;
 55	} else {
 56		cpu->gprs[ARM_PC] = BASE_CART0;
 57	}
 58	_ARMSetMode(cpu, MODE_ARM);
 59	ARMWritePC(cpu);
 60}
 61
 62static void _RegisterRamReset(struct GBA* gba) {
 63	uint32_t registers = gba->cpu->gprs[0];
 64	struct ARMCore* cpu = gba->cpu;
 65	cpu->memory.store16(cpu, BASE_IO | REG_DISPCNT, 0x0080, 0);
 66	if (registers & 0x01) {
 67		memset(gba->memory.wram, 0, SIZE_WORKING_RAM);
 68	}
 69	if (registers & 0x02) {
 70		memset(gba->memory.iwram, 0, SIZE_WORKING_IRAM - 0x200);
 71	}
 72	if (registers & 0x04) {
 73		memset(gba->video.palette, 0, SIZE_PALETTE_RAM);
 74	}
 75	if (registers & 0x08) {
 76		memset(gba->video.vram, 0, SIZE_VRAM);
 77	}
 78	if (registers & 0x10) {
 79		memset(gba->video.oam.raw, 0, SIZE_OAM);
 80	}
 81	if (registers & 0x20) {
 82		cpu->memory.store16(cpu, BASE_IO | REG_SIOCNT, 0x0000, 0);
 83		cpu->memory.store16(cpu, BASE_IO | REG_RCNT, RCNT_INITIAL, 0);
 84		cpu->memory.store16(cpu, BASE_IO | REG_SIOMLT_SEND, 0, 0);
 85		cpu->memory.store16(cpu, BASE_IO | REG_JOYCNT, 0, 0);
 86		cpu->memory.store32(cpu, BASE_IO | REG_JOY_RECV_LO, 0, 0);
 87		cpu->memory.store32(cpu, BASE_IO | REG_JOY_TRANS_LO, 0, 0);
 88	}
 89	if (registers & 0x40) {
 90		cpu->memory.store16(cpu, BASE_IO | REG_SOUND1CNT_LO, 0, 0);
 91		cpu->memory.store16(cpu, BASE_IO | REG_SOUND1CNT_HI, 0, 0);
 92		cpu->memory.store16(cpu, BASE_IO | REG_SOUND1CNT_X, 0, 0);
 93		cpu->memory.store16(cpu, BASE_IO | REG_SOUND2CNT_LO, 0, 0);
 94		cpu->memory.store16(cpu, BASE_IO | REG_SOUND2CNT_HI, 0, 0);
 95		cpu->memory.store16(cpu, BASE_IO | REG_SOUND3CNT_LO, 0, 0);
 96		cpu->memory.store16(cpu, BASE_IO | REG_SOUND3CNT_HI, 0, 0);
 97		cpu->memory.store16(cpu, BASE_IO | REG_SOUND3CNT_X, 0, 0);
 98		cpu->memory.store16(cpu, BASE_IO | REG_SOUND4CNT_LO, 0, 0);
 99		cpu->memory.store16(cpu, BASE_IO | REG_SOUND4CNT_HI, 0, 0);
100		cpu->memory.store16(cpu, BASE_IO | REG_SOUNDCNT_LO, 0, 0);
101		cpu->memory.store16(cpu, BASE_IO | REG_SOUNDCNT_HI, 0, 0);
102		cpu->memory.store16(cpu, BASE_IO | REG_SOUNDCNT_X, 0, 0);
103		cpu->memory.store16(cpu, BASE_IO | REG_SOUNDBIAS, 0x200, 0);
104		memset(gba->audio.psg.ch3.wavedata32, 0, sizeof(gba->audio.psg.ch3.wavedata32));
105	}
106	if (registers & 0x80) {
107		cpu->memory.store16(cpu, BASE_IO | REG_DISPSTAT, 0, 0);
108		cpu->memory.store16(cpu, BASE_IO | REG_VCOUNT, 0, 0);
109		cpu->memory.store16(cpu, BASE_IO | REG_BG0CNT, 0, 0);
110		cpu->memory.store16(cpu, BASE_IO | REG_BG1CNT, 0, 0);
111		cpu->memory.store16(cpu, BASE_IO | REG_BG2CNT, 0, 0);
112		cpu->memory.store16(cpu, BASE_IO | REG_BG3CNT, 0, 0);
113		cpu->memory.store16(cpu, BASE_IO | REG_BG0HOFS, 0, 0);
114		cpu->memory.store16(cpu, BASE_IO | REG_BG0VOFS, 0, 0);
115		cpu->memory.store16(cpu, BASE_IO | REG_BG1HOFS, 0, 0);
116		cpu->memory.store16(cpu, BASE_IO | REG_BG1VOFS, 0, 0);
117		cpu->memory.store16(cpu, BASE_IO | REG_BG2HOFS, 0, 0);
118		cpu->memory.store16(cpu, BASE_IO | REG_BG2VOFS, 0, 0);
119		cpu->memory.store16(cpu, BASE_IO | REG_BG3HOFS, 0, 0);
120		cpu->memory.store16(cpu, BASE_IO | REG_BG3VOFS, 0, 0);
121		cpu->memory.store16(cpu, BASE_IO | REG_BG2PA, 0x100, 0);
122		cpu->memory.store16(cpu, BASE_IO | REG_BG2PB, 0, 0);
123		cpu->memory.store16(cpu, BASE_IO | REG_BG2PC, 0, 0);
124		cpu->memory.store16(cpu, BASE_IO | REG_BG2PD, 0x100, 0);
125		cpu->memory.store32(cpu, BASE_IO | REG_BG2X_LO, 0, 0);
126		cpu->memory.store32(cpu, BASE_IO | REG_BG2Y_LO, 0, 0);
127		cpu->memory.store16(cpu, BASE_IO | REG_BG3PA, 0x100, 0);
128		cpu->memory.store16(cpu, BASE_IO | REG_BG3PB, 0, 0);
129		cpu->memory.store16(cpu, BASE_IO | REG_BG3PC, 0, 0);
130		cpu->memory.store16(cpu, BASE_IO | REG_BG3PD, 0x100, 0);
131		cpu->memory.store32(cpu, BASE_IO | REG_BG3X_LO, 0, 0);
132		cpu->memory.store32(cpu, BASE_IO | REG_BG3Y_LO, 0, 0);
133		cpu->memory.store16(cpu, BASE_IO | REG_WIN0H, 0, 0);
134		cpu->memory.store16(cpu, BASE_IO | REG_WIN1H, 0, 0);
135		cpu->memory.store16(cpu, BASE_IO | REG_WIN0V, 0, 0);
136		cpu->memory.store16(cpu, BASE_IO | REG_WIN1V, 0, 0);
137		cpu->memory.store16(cpu, BASE_IO | REG_WININ, 0, 0);
138		cpu->memory.store16(cpu, BASE_IO | REG_WINOUT, 0, 0);
139		cpu->memory.store16(cpu, BASE_IO | REG_MOSAIC, 0, 0);
140		cpu->memory.store16(cpu, BASE_IO | REG_BLDCNT, 0, 0);
141		cpu->memory.store16(cpu, BASE_IO | REG_BLDALPHA, 0, 0);
142		cpu->memory.store16(cpu, BASE_IO | REG_BLDY, 0, 0);
143		cpu->memory.store16(cpu, BASE_IO | REG_DMA0SAD_LO, 0, 0);
144		cpu->memory.store16(cpu, BASE_IO | REG_DMA0SAD_HI, 0, 0);
145		cpu->memory.store16(cpu, BASE_IO | REG_DMA0DAD_LO, 0, 0);
146		cpu->memory.store16(cpu, BASE_IO | REG_DMA0DAD_HI, 0, 0);
147		cpu->memory.store16(cpu, BASE_IO | REG_DMA0CNT_LO, 0, 0);
148		cpu->memory.store16(cpu, BASE_IO | REG_DMA0CNT_HI, 0, 0);
149		cpu->memory.store16(cpu, BASE_IO | REG_DMA1SAD_LO, 0, 0);
150		cpu->memory.store16(cpu, BASE_IO | REG_DMA1SAD_HI, 0, 0);
151		cpu->memory.store16(cpu, BASE_IO | REG_DMA1DAD_LO, 0, 0);
152		cpu->memory.store16(cpu, BASE_IO | REG_DMA1DAD_HI, 0, 0);
153		cpu->memory.store16(cpu, BASE_IO | REG_DMA1CNT_LO, 0, 0);
154		cpu->memory.store16(cpu, BASE_IO | REG_DMA1CNT_HI, 0, 0);
155		cpu->memory.store16(cpu, BASE_IO | REG_DMA2SAD_LO, 0, 0);
156		cpu->memory.store16(cpu, BASE_IO | REG_DMA2SAD_HI, 0, 0);
157		cpu->memory.store16(cpu, BASE_IO | REG_DMA2DAD_LO, 0, 0);
158		cpu->memory.store16(cpu, BASE_IO | REG_DMA2DAD_HI, 0, 0);
159		cpu->memory.store16(cpu, BASE_IO | REG_DMA2CNT_LO, 0, 0);
160		cpu->memory.store16(cpu, BASE_IO | REG_DMA2CNT_HI, 0, 0);
161		cpu->memory.store16(cpu, BASE_IO | REG_DMA3SAD_LO, 0, 0);
162		cpu->memory.store16(cpu, BASE_IO | REG_DMA3SAD_HI, 0, 0);
163		cpu->memory.store16(cpu, BASE_IO | REG_DMA3DAD_LO, 0, 0);
164		cpu->memory.store16(cpu, BASE_IO | REG_DMA3DAD_HI, 0, 0);
165		cpu->memory.store16(cpu, BASE_IO | REG_DMA3CNT_LO, 0, 0);
166		cpu->memory.store16(cpu, BASE_IO | REG_DMA3CNT_HI, 0, 0);
167		cpu->memory.store16(cpu, BASE_IO | REG_TM0CNT_LO, 0, 0);
168		cpu->memory.store16(cpu, BASE_IO | REG_TM0CNT_HI, 0, 0);
169		cpu->memory.store16(cpu, BASE_IO | REG_TM1CNT_LO, 0, 0);
170		cpu->memory.store16(cpu, BASE_IO | REG_TM1CNT_HI, 0, 0);
171		cpu->memory.store16(cpu, BASE_IO | REG_TM2CNT_LO, 0, 0);
172		cpu->memory.store16(cpu, BASE_IO | REG_TM2CNT_HI, 0, 0);
173		cpu->memory.store16(cpu, BASE_IO | REG_TM3CNT_LO, 0, 0);
174		cpu->memory.store16(cpu, BASE_IO | REG_TM3CNT_HI, 0, 0);
175		cpu->memory.store16(cpu, BASE_IO | REG_IE, 0, 0);
176		cpu->memory.store16(cpu, BASE_IO | REG_IF, 0xFFFF, 0);
177		cpu->memory.store16(cpu, BASE_IO | REG_WAITCNT, 0, 0);
178		cpu->memory.store16(cpu, BASE_IO | REG_IME, 0, 0);
179	}
180	if (registers & 0x9C) {
181		gba->video.renderer->reset(gba->video.renderer);
182		gba->video.renderer->writeVideoRegister(gba->video.renderer, REG_DISPCNT, gba->memory.io[REG_DISPCNT >> 1]);
183		int i;
184		for (i = REG_BG0CNT; i < REG_SOUND1CNT_LO; i += 2) {
185			gba->video.renderer->writeVideoRegister(gba->video.renderer, i, gba->memory.io[i >> 1]);
186		}
187	}
188}
189
190static void _BgAffineSet(struct GBA* gba) {
191	struct ARMCore* cpu = gba->cpu;
192	int i = cpu->gprs[2];
193	float ox, oy;
194	float cx, cy;
195	float sx, sy;
196	float theta;
197	int offset = cpu->gprs[0];
198	int destination = cpu->gprs[1];
199	float a, b, c, d;
200	float rx, ry;
201	while (i--) {
202		// [ sx   0  0 ]   [ cos(theta)  -sin(theta)  0 ]   [ 1  0  cx - ox ]   [ A B rx ]
203		// [  0  sy  0 ] * [ sin(theta)   cos(theta)  0 ] * [ 0  1  cy - oy ] = [ C D ry ]
204		// [  0   0  1 ]   [     0            0       1 ]   [ 0  0     1    ]   [ 0 0  1 ]
205		ox = (int32_t) cpu->memory.load32(cpu, offset, 0) / 256.f;
206		oy = (int32_t) cpu->memory.load32(cpu, offset + 4, 0) / 256.f;
207		cx = (int16_t) cpu->memory.load16(cpu, offset + 8, 0);
208		cy = (int16_t) cpu->memory.load16(cpu, offset + 10, 0);
209		sx = (int16_t) cpu->memory.load16(cpu, offset + 12, 0) / 256.f;
210		sy = (int16_t) cpu->memory.load16(cpu, offset + 14, 0) / 256.f;
211		theta = (cpu->memory.load16(cpu, offset + 16, 0) >> 8) / 128.f * M_PI;
212		offset += 20;
213		// Rotation
214		a = d = cosf(theta);
215		b = c = sinf(theta);
216		// Scale
217		a *= sx;
218		b *= -sx;
219		c *= sy;
220		d *= sy;
221		// Translate
222		rx = ox - (a * cx + b * cy);
223		ry = oy - (c * cx + d * cy);
224		cpu->memory.store16(cpu, destination, a * 256, 0);
225		cpu->memory.store16(cpu, destination + 2, b * 256, 0);
226		cpu->memory.store16(cpu, destination + 4, c * 256, 0);
227		cpu->memory.store16(cpu, destination + 6, d * 256, 0);
228		cpu->memory.store32(cpu, destination + 8, rx * 256, 0);
229		cpu->memory.store32(cpu, destination + 12, ry * 256, 0);
230		destination += 16;
231	}
232}
233
234static void _ObjAffineSet(struct GBA* gba) {
235	struct ARMCore* cpu = gba->cpu;
236	int i = cpu->gprs[2];
237	float sx, sy;
238	float theta;
239	int offset = cpu->gprs[0];
240	int destination = cpu->gprs[1];
241	int diff = cpu->gprs[3];
242	float a, b, c, d;
243	while (i--) {
244		// [ sx   0 ]   [ cos(theta)  -sin(theta) ]   [ A B ]
245		// [  0  sy ] * [ sin(theta)   cos(theta) ] = [ C D ]
246		sx = (int16_t) cpu->memory.load16(cpu, offset, 0) / 256.f;
247		sy = (int16_t) cpu->memory.load16(cpu, offset + 2, 0) / 256.f;
248		theta = (cpu->memory.load16(cpu, offset + 4, 0) >> 8) / 128.f * M_PI;
249		offset += 8;
250		// Rotation
251		a = d = cosf(theta);
252		b = c = sinf(theta);
253		// Scale
254		a *= sx;
255		b *= -sx;
256		c *= sy;
257		d *= sy;
258		cpu->memory.store16(cpu, destination, a * 256, 0);
259		cpu->memory.store16(cpu, destination + diff, b * 256, 0);
260		cpu->memory.store16(cpu, destination + diff * 2, c * 256, 0);
261		cpu->memory.store16(cpu, destination + diff * 3, d * 256, 0);
262		destination += diff * 4;
263	}
264}
265
266static void _MidiKey2Freq(struct GBA* gba) {
267	struct ARMCore* cpu = gba->cpu;
268
269	int oldRegion = gba->memory.activeRegion;
270	gba->memory.activeRegion = REGION_BIOS;
271	uint32_t key = cpu->memory.load32(cpu, cpu->gprs[0] + 4, 0);
272	gba->memory.activeRegion = oldRegion;
273
274	cpu->gprs[0] = key / exp2f((180.f - cpu->gprs[1] - cpu->gprs[2] / 256.f) / 12.f);
275}
276
277static void _Div(struct GBA* gba, int32_t num, int32_t denom) {
278	struct ARMCore* cpu = gba->cpu;
279	if (denom != 0 && (denom != -1 || num != INT32_MIN)) {
280		div_t result = div(num, denom);
281		cpu->gprs[0] = result.quot;
282		cpu->gprs[1] = result.rem;
283		cpu->gprs[3] = abs(result.quot);
284	} else if (denom == 0) {
285		mLOG(GBA_BIOS, GAME_ERROR, "Attempting to divide %i by zero!", num);
286		// If abs(num) > 1, this should hang, but that would be painful to
287		// emulate in HLE, and no game will get into a state where it hangs...
288		cpu->gprs[0] = (num < 0) ? -1 : 1;
289		cpu->gprs[1] = num;
290		cpu->gprs[3] = 1;
291	} else {
292		mLOG(GBA_BIOS, GAME_ERROR, "Attempting to divide INT_MIN by -1!");
293		cpu->gprs[0] = INT32_MIN;
294		cpu->gprs[1] = 0;
295		cpu->gprs[3] = INT32_MIN;
296	}
297	int loops = clz32(denom) - clz32(num);
298	if (loops < 1) {
299		loops = 1;
300	}
301	gba->biosStall = 4 /* prologue */ + 13 * loops + 7 /* epilogue */;
302}
303
304static int16_t _ArcTan(int32_t i, int32_t* r1, int32_t* r3, uint32_t* cycles) {
305	int currentCycles = 37;
306	currentCycles += _mulWait(i * i);
307	int32_t a = -((i * i) >> 14);
308	currentCycles += _mulWait(0xA9 * a);
309	int32_t b = ((0xA9 * a) >> 14) + 0x390;
310	currentCycles += _mulWait(b * a);
311	b = ((b * a) >> 14) + 0x91C;
312	currentCycles += _mulWait(b * a);
313	b = ((b * a) >> 14) + 0xFB6;
314	currentCycles += _mulWait(b * a);
315	b = ((b * a) >> 14) + 0x16AA;
316	currentCycles += _mulWait(b * a);
317	b = ((b * a) >> 14) + 0x2081;
318	currentCycles += _mulWait(b * a);
319	b = ((b * a) >> 14) + 0x3651;
320	currentCycles += _mulWait(b * a);
321	b = ((b * a) >> 14) + 0xA2F9;
322	if (r1) {
323		*r1 = a;
324	}
325	if (r3) {
326		*r3 = b;
327	}
328	*cycles = currentCycles;
329	return (i * b) >> 16;
330}
331
332static int16_t _ArcTan2(int32_t x, int32_t y, int32_t* r1, uint32_t* cycles) {
333	if (!y) {
334		if (x >= 0) {
335			return 0;
336		}
337		return 0x8000;
338	}
339	if (!x) {
340		if (y >= 0) {
341			return 0x4000;
342		}
343		return 0xC000;
344	}
345	if (y >= 0) {
346		if (x >= 0) {
347			if (x >= y) {
348				return _ArcTan((y << 14) / x, r1, NULL, cycles);
349			}
350		} else if (-x >= y) {
351			return _ArcTan((y << 14) / x, r1, NULL, cycles) + 0x8000;
352		}
353		return 0x4000 - _ArcTan((x << 14) / y, r1, NULL, cycles);
354	} else {
355		if (x <= 0) {
356			if (-x > -y) {
357				return _ArcTan((y << 14) / x, r1, NULL, cycles) + 0x8000;
358			}
359		} else if (x >= -y) {
360			return _ArcTan((y << 14) / x, r1, NULL, cycles) + 0x10000;
361		}
362		return 0xC000 - _ArcTan((x << 14) / y, r1, NULL, cycles);
363	}
364}
365
366static int32_t _Sqrt(uint32_t x, uint32_t* cycles) {
367	if (!x) {
368		*cycles = 53;
369		return 0;
370	}
371	int32_t currentCycles = 15;
372	uint32_t lower;
373	uint32_t upper = x;
374	uint32_t bound = 1;
375	while (bound < upper) {
376		upper >>= 1;
377		bound <<= 1;
378		currentCycles += 6;
379	}
380	while (true) {
381		currentCycles += 6;
382		upper = x;
383		uint32_t accum = 0;
384		lower = bound;
385		while (true) {
386			currentCycles += 5;
387			uint32_t oldLower = lower;
388			if (lower <= upper >> 1) {
389				lower <<= 1;
390			}
391			if (oldLower >= upper >> 1) {
392				break;
393			}
394		}
395		while (true) {
396			currentCycles += 8;
397			accum <<= 1;
398			if (upper >= lower) {
399				++accum;
400				upper -= lower;
401			}
402			if (lower == bound) {
403				break;
404			}
405			lower >>= 1;
406		}
407		uint32_t oldBound = bound;
408		bound += accum;
409		bound >>= 1;
410		if (bound >= oldBound) {
411			bound = oldBound;
412			break;
413		}
414	}
415	*cycles = currentCycles;
416	return bound;
417}
418
419void GBASwi16(struct ARMCore* cpu, int immediate) {
420	struct GBA* gba = (struct GBA*) cpu->master;
421	mLOG(GBA_BIOS, DEBUG, "SWI: %02X r0: %08X r1: %08X r2: %08X r3: %08X",
422	    immediate, cpu->gprs[0], cpu->gprs[1], cpu->gprs[2], cpu->gprs[3]);
423
424	switch (immediate) {
425	case 0xF0: // Used for internal stall counting
426		cpu->gprs[12] = gba->biosStall;
427		return;
428	case 0xFA:
429		GBAPrintFlush(gba);
430		return;
431	}
432
433	if (gba->memory.fullBios) {
434		ARMRaiseSWI(cpu);
435		return;
436	}
437
438	bool useStall = false;
439	switch (immediate) {
440	case GBA_SWI_SOFT_RESET:
441		_SoftReset(gba);
442		break;
443	case GBA_SWI_REGISTER_RAM_RESET:
444		_RegisterRamReset(gba);
445		break;
446	case GBA_SWI_HALT:
447		ARMRaiseSWI(cpu);
448		return;
449	case GBA_SWI_STOP:
450		GBAStop(gba);
451		break;
452	case GBA_SWI_VBLANK_INTR_WAIT:
453	// VBlankIntrWait
454	// Fall through:
455	case GBA_SWI_INTR_WAIT:
456		// IntrWait
457		ARMRaiseSWI(cpu);
458		return;
459	case GBA_SWI_DIV:
460		useStall = true;
461		_Div(gba, cpu->gprs[0], cpu->gprs[1]);
462		break;
463	case GBA_SWI_DIV_ARM:
464		useStall = true;
465		_Div(gba, cpu->gprs[1], cpu->gprs[0]);
466		break;
467	case GBA_SWI_SQRT:
468		useStall = true;
469		cpu->gprs[0] = _Sqrt(cpu->gprs[0], &gba->biosStall);
470		break;
471	case GBA_SWI_ARCTAN:
472		useStall = true;
473		cpu->gprs[0] = _ArcTan(cpu->gprs[0], &cpu->gprs[1], &cpu->gprs[3], &gba->biosStall);
474		break;
475	case GBA_SWI_ARCTAN2:
476		useStall = true;
477		cpu->gprs[0] = (uint16_t) _ArcTan2(cpu->gprs[0], cpu->gprs[1], &cpu->gprs[1], &gba->biosStall);
478		cpu->gprs[3] = 0x170;
479		break;
480	case GBA_SWI_CPU_SET:
481	case GBA_SWI_CPU_FAST_SET:
482		if (cpu->gprs[0] >> BASE_OFFSET < REGION_WORKING_RAM) {
483			mLOG(GBA_BIOS, GAME_ERROR, "Cannot CpuSet from BIOS");
484			break;
485		}
486		if (cpu->gprs[0] & (cpu->gprs[2] & (1 << 26) ? 3 : 1)) {
487			mLOG(GBA_BIOS, GAME_ERROR, "Misaligned CpuSet source");
488		}
489		if (cpu->gprs[1] & (cpu->gprs[2] & (1 << 26) ? 3 : 1)) {
490			mLOG(GBA_BIOS, GAME_ERROR, "Misaligned CpuSet destination");
491		}
492		ARMRaiseSWI(cpu);
493		return;
494	case GBA_SWI_GET_BIOS_CHECKSUM:
495		cpu->gprs[0] = GBA_BIOS_CHECKSUM;
496		cpu->gprs[1] = 1;
497		cpu->gprs[3] = SIZE_BIOS;
498		break;
499	case GBA_SWI_BG_AFFINE_SET:
500		_BgAffineSet(gba);
501		break;
502	case GBA_SWI_OBJ_AFFINE_SET:
503		_ObjAffineSet(gba);
504		break;
505	case GBA_SWI_BIT_UNPACK:
506		if (cpu->gprs[0] < BASE_WORKING_RAM) {
507			mLOG(GBA_BIOS, GAME_ERROR, "Bad BitUnPack source");
508			break;
509		}
510		switch (cpu->gprs[1] >> BASE_OFFSET) {
511		default:
512			mLOG(GBA_BIOS, GAME_ERROR, "Bad BitUnPack destination");
513		// Fall through
514		case REGION_WORKING_RAM:
515		case REGION_WORKING_IRAM:
516		case REGION_VRAM:
517			_unBitPack(gba);
518			break;
519		}
520		break;
521	case GBA_SWI_LZ77_UNCOMP_WRAM:
522	case GBA_SWI_LZ77_UNCOMP_VRAM:
523		if (cpu->gprs[0] < BASE_WORKING_RAM) {
524			mLOG(GBA_BIOS, GAME_ERROR, "Bad LZ77 source");
525			break;
526		}
527		switch (cpu->gprs[1] >> BASE_OFFSET) {
528		default:
529			mLOG(GBA_BIOS, GAME_ERROR, "Bad LZ77 destination");
530		// Fall through
531		case REGION_WORKING_RAM:
532		case REGION_WORKING_IRAM:
533		case REGION_VRAM:
534			_unLz77(gba, immediate == GBA_SWI_LZ77_UNCOMP_WRAM ? 1 : 2);
535			break;
536		}
537		break;
538	case GBA_SWI_HUFFMAN_UNCOMP:
539		if (cpu->gprs[0] < BASE_WORKING_RAM) {
540			mLOG(GBA_BIOS, GAME_ERROR, "Bad Huffman source");
541			break;
542		}
543		switch (cpu->gprs[1] >> BASE_OFFSET) {
544		default:
545			mLOG(GBA_BIOS, GAME_ERROR, "Bad Huffman destination");
546		// Fall through
547		case REGION_WORKING_RAM:
548		case REGION_WORKING_IRAM:
549		case REGION_VRAM:
550			_unHuffman(gba);
551			break;
552		}
553		break;
554	case GBA_SWI_RL_UNCOMP_WRAM:
555	case GBA_SWI_RL_UNCOMP_VRAM:
556		if (cpu->gprs[0] < BASE_WORKING_RAM) {
557			mLOG(GBA_BIOS, GAME_ERROR, "Bad RL source");
558			break;
559		}
560		switch (cpu->gprs[1] >> BASE_OFFSET) {
561		default:
562			mLOG(GBA_BIOS, GAME_ERROR, "Bad RL destination");
563		// Fall through
564		case REGION_WORKING_RAM:
565		case REGION_WORKING_IRAM:
566		case REGION_VRAM:
567			_unRl(gba, immediate == GBA_SWI_RL_UNCOMP_WRAM ? 1 : 2);
568			break;
569		}
570		break;
571	case GBA_SWI_DIFF_8BIT_UNFILTER_WRAM:
572	case GBA_SWI_DIFF_8BIT_UNFILTER_VRAM:
573	case GBA_SWI_DIFF_16BIT_UNFILTER:
574		if (cpu->gprs[0] < BASE_WORKING_RAM) {
575			mLOG(GBA_BIOS, GAME_ERROR, "Bad UnFilter source");
576			break;
577		}
578		switch (cpu->gprs[1] >> BASE_OFFSET) {
579		default:
580			mLOG(GBA_BIOS, GAME_ERROR, "Bad UnFilter destination");
581		// Fall through
582		case REGION_WORKING_RAM:
583		case REGION_WORKING_IRAM:
584		case REGION_VRAM:
585			_unFilter(gba, immediate == GBA_SWI_DIFF_16BIT_UNFILTER ? 2 : 1, immediate == GBA_SWI_DIFF_8BIT_UNFILTER_WRAM ? 1 : 2);
586			break;
587		}
588		break;
589	case GBA_SWI_SOUND_BIAS:
590		// SoundBias is mostly meaningless here
591		mLOG(GBA_BIOS, STUB, "Stub software interrupt: SoundBias (19)");
592		break;
593	case GBA_SWI_MIDI_KEY_2_FREQ:
594		_MidiKey2Freq(gba);
595		break;
596	case GBA_SWI_SOUND_DRIVER_GET_JUMP_LIST:
597		ARMRaiseSWI(cpu);
598		return;
599	default:
600		mLOG(GBA_BIOS, STUB, "Stub software interrupt: %02X", immediate);
601	}
602	if (useStall) {
603		if (gba->biosStall >= 18) {
604			gba->biosStall -= 18;
605			gba->cpu->cycles += gba->biosStall & 3;
606			gba->biosStall &= ~3;
607			ARMRaiseSWI(cpu);
608		} else {
609			gba->cpu->cycles += gba->biosStall;
610			useStall = false;
611		}
612	}
613	if (!useStall) {
614		gba->cpu->cycles += 45 + cpu->memory.activeNonseqCycles16 /* 8 bit load for SWI # */;
615		// Return cycles
616		if (gba->cpu->executionMode == MODE_ARM) {
617			gba->cpu->cycles += cpu->memory.activeNonseqCycles32 + cpu->memory.activeSeqCycles32;
618		} else {
619			gba->cpu->cycles += cpu->memory.activeNonseqCycles16 + cpu->memory.activeSeqCycles16;
620		}
621	}
622	gba->memory.biosPrefetch = 0xE3A02004;
623}
624
625void GBASwi32(struct ARMCore* cpu, int immediate) {
626	GBASwi16(cpu, immediate >> 16);
627}
628
629uint32_t GBAChecksum(uint32_t* memory, size_t size) {
630	size_t i;
631	uint32_t sum = 0;
632	for (i = 0; i < size; i += 4) {
633		sum += memory[i >> 2];
634	}
635	return sum;
636}
637
638static void _unLz77(struct GBA* gba, int width) {
639	struct ARMCore* cpu = gba->cpu;
640	uint32_t source = cpu->gprs[0];
641	uint32_t dest = cpu->gprs[1];
642	int remaining = (cpu->memory.load32(cpu, source, 0) & 0xFFFFFF00) >> 8;
643	// We assume the signature byte (0x10) is correct
644	int blockheader = 0; // Some compilers warn if this isn't set, even though it's trivially provably always set
645	source += 4;
646	int blocksRemaining = 0;
647	uint32_t disp;
648	int bytes;
649	int byte;
650	int halfword = 0;
651	while (remaining > 0) {
652		if (blocksRemaining) {
653			if (blockheader & 0x80) {
654				// Compressed
655				int block = cpu->memory.load8(cpu, source + 1, 0) | (cpu->memory.load8(cpu, source, 0) << 8);
656				source += 2;
657				disp = dest - (block & 0x0FFF) - 1;
658				bytes = (block >> 12) + 3;
659				while (bytes--) {
660					if (remaining) {
661						--remaining;
662					}
663					if (width == 2) {
664						byte = (int16_t) cpu->memory.load16(cpu, disp & ~1, 0);
665						if (dest & 1) {
666							byte >>= (disp & 1) * 8;
667							halfword |= byte << 8;
668							cpu->memory.store16(cpu, dest ^ 1, halfword, 0);
669						} else {
670							byte >>= (disp & 1) * 8;
671							halfword = byte & 0xFF;
672						}
673					} else {
674						byte = cpu->memory.load8(cpu, disp, 0);
675						cpu->memory.store8(cpu, dest, byte, 0);
676					}
677					++disp;
678					++dest;
679				}
680			} else {
681				// Uncompressed
682				byte = cpu->memory.load8(cpu, source, 0);
683				++source;
684				if (width == 2) {
685					if (dest & 1) {
686						halfword |= byte << 8;
687						cpu->memory.store16(cpu, dest ^ 1, halfword, 0);
688					} else {
689						halfword = byte;
690					}
691				} else {
692					cpu->memory.store8(cpu, dest, byte, 0);
693				}
694				++dest;
695				--remaining;
696			}
697			blockheader <<= 1;
698			--blocksRemaining;
699		} else {
700			blockheader = cpu->memory.load8(cpu, source, 0);
701			++source;
702			blocksRemaining = 8;
703		}
704	}
705	cpu->gprs[0] = source;
706	cpu->gprs[1] = dest;
707	cpu->gprs[3] = 0;
708}
709
710DECL_BITFIELD(HuffmanNode, uint8_t);
711DECL_BITS(HuffmanNode, Offset, 0, 6);
712DECL_BIT(HuffmanNode, RTerm, 6);
713DECL_BIT(HuffmanNode, LTerm, 7);
714
715static void _unHuffman(struct GBA* gba) {
716	struct ARMCore* cpu = gba->cpu;
717	uint32_t source = cpu->gprs[0] & 0xFFFFFFFC;
718	uint32_t dest = cpu->gprs[1];
719	uint32_t header = cpu->memory.load32(cpu, source, 0);
720	int remaining = header >> 8;
721	unsigned bits = header & 0xF;
722	if (bits == 0) {
723		mLOG(GBA_BIOS, GAME_ERROR, "Invalid Huffman bits");
724		bits = 8;
725	}
726	if (32 % bits || bits == 1) {
727		mLOG(GBA_BIOS, STUB, "Unimplemented unaligned Huffman");
728		return;
729	}
730	// We assume the signature byte (0x20) is correct
731	int treesize = (cpu->memory.load8(cpu, source + 4, 0) << 1) + 1;
732	int block = 0;
733	uint32_t treeBase = source + 5;
734	source += 5 + treesize;
735	uint32_t nPointer = treeBase;
736	HuffmanNode node;
737	int bitsRemaining;
738	int readBits;
739	int bitsSeen = 0;
740	node = cpu->memory.load8(cpu, nPointer, 0);
741	while (remaining > 0) {
742		uint32_t bitstream = cpu->memory.load32(cpu, source, 0);
743		source += 4;
744		for (bitsRemaining = 32; bitsRemaining > 0 && remaining > 0; --bitsRemaining, bitstream <<= 1) {
745			uint32_t next = (nPointer & ~1) + HuffmanNodeGetOffset(node) * 2 + 2;
746			if (bitstream & 0x80000000) {
747				// Go right
748				if (HuffmanNodeIsRTerm(node)) {
749					readBits = cpu->memory.load8(cpu, next + 1, 0);
750				} else {
751					nPointer = next + 1;
752					node = cpu->memory.load8(cpu, nPointer, 0);
753					continue;
754				}
755			} else {
756				// Go left
757				if (HuffmanNodeIsLTerm(node)) {
758					readBits = cpu->memory.load8(cpu, next, 0);
759				} else {
760					nPointer = next;
761					node = cpu->memory.load8(cpu, nPointer, 0);
762					continue;
763				}
764			}
765
766			block |= (readBits & ((1 << bits) - 1)) << bitsSeen;
767			bitsSeen += bits;
768			nPointer = treeBase;
769			node = cpu->memory.load8(cpu, nPointer, 0);
770			if (bitsSeen == 32) {
771				bitsSeen = 0;
772				cpu->memory.store32(cpu, dest, block, 0);
773				dest += 4;
774				remaining -= 4;
775				block = 0;
776			}
777		}
778	}
779	cpu->gprs[0] = source;
780	cpu->gprs[1] = dest;
781}
782
783static void _unRl(struct GBA* gba, int width) {
784	struct ARMCore* cpu = gba->cpu;
785	uint32_t source = cpu->gprs[0];
786	int remaining = (cpu->memory.load32(cpu, source & 0xFFFFFFFC, 0) & 0xFFFFFF00) >> 8;
787	int padding = (4 - remaining) & 0x3;
788	// We assume the signature byte (0x30) is correct
789	int blockheader;
790	int block;
791	source += 4;
792	uint32_t dest = cpu->gprs[1];
793	int halfword = 0;
794	while (remaining > 0) {
795		blockheader = cpu->memory.load8(cpu, source, 0);
796		++source;
797		if (blockheader & 0x80) {
798			// Compressed
799			blockheader &= 0x7F;
800			blockheader += 3;
801			block = cpu->memory.load8(cpu, source, 0);
802			++source;
803			while (blockheader-- && remaining) {
804				--remaining;
805				if (width == 2) {
806					if (dest & 1) {
807						halfword |= block << 8;
808						cpu->memory.store16(cpu, dest ^ 1, halfword, 0);
809					} else {
810						halfword = block;
811					}
812				} else {
813					cpu->memory.store8(cpu, dest, block, 0);
814				}
815				++dest;
816			}
817		} else {
818			// Uncompressed
819			blockheader++;
820			while (blockheader-- && remaining) {
821				--remaining;
822				int byte = cpu->memory.load8(cpu, source, 0);
823				++source;
824				if (width == 2) {
825					if (dest & 1) {
826						halfword |= byte << 8;
827						cpu->memory.store16(cpu, dest ^ 1, halfword, 0);
828					} else {
829						halfword = byte;
830					}
831				} else {
832					cpu->memory.store8(cpu, dest, byte, 0);
833				}
834				++dest;
835			}
836		}
837	}
838	if (width == 2) {
839		if (dest & 1) {
840			--padding;
841			++dest;
842		}
843		for (; padding > 0; padding -= 2, dest += 2) {
844			cpu->memory.store16(cpu, dest, 0, 0);
845		}
846	} else {
847		while (padding--) {
848			cpu->memory.store8(cpu, dest, 0, 0);
849			++dest;
850		}
851	}
852	cpu->gprs[0] = source;
853	cpu->gprs[1] = dest;
854}
855
856static void _unFilter(struct GBA* gba, int inwidth, int outwidth) {
857	struct ARMCore* cpu = gba->cpu;
858	uint32_t source = cpu->gprs[0] & 0xFFFFFFFC;
859	uint32_t dest = cpu->gprs[1];
860	uint32_t header = cpu->memory.load32(cpu, source, 0);
861	int remaining = header >> 8;
862	// We assume the signature nybble (0x8) is correct
863	uint16_t halfword = 0;
864	uint16_t old = 0;
865	source += 4;
866	while (remaining > 0) {
867		uint16_t new;
868		if (inwidth == 1) {
869			new = cpu->memory.load8(cpu, source, 0);
870		} else {
871			new = cpu->memory.load16(cpu, source, 0);
872		}
873		new += old;
874		if (outwidth > inwidth) {
875			halfword >>= 8;
876			halfword |= (new << 8);
877			if (source & 1) {
878				cpu->memory.store16(cpu, dest, halfword, 0);
879				dest += outwidth;
880				remaining -= outwidth;
881			}
882		} else if (outwidth == 1) {
883			cpu->memory.store8(cpu, dest, new, 0);
884			dest += outwidth;
885			remaining -= outwidth;
886		} else {
887			cpu->memory.store16(cpu, dest, new, 0);
888			dest += outwidth;
889			remaining -= outwidth;
890		}
891		old = new;
892		source += inwidth;
893	}
894	cpu->gprs[0] = source;
895	cpu->gprs[1] = dest;
896}
897
898static void _unBitPack(struct GBA* gba) {
899	struct ARMCore* cpu = gba->cpu;
900	uint32_t source = cpu->gprs[0];
901	uint32_t dest = cpu->gprs[1];
902	uint32_t info = cpu->gprs[2];
903	unsigned sourceLen = cpu->memory.load16(cpu, info, 0);
904	unsigned sourceWidth = cpu->memory.load8(cpu, info + 2, 0);
905	unsigned destWidth = cpu->memory.load8(cpu, info + 3, 0);
906	switch (sourceWidth) {
907	case 1:
908	case 2:
909	case 4:
910	case 8:
911		break;
912	default:
913		mLOG(GBA_BIOS, GAME_ERROR, "Bad BitUnPack source width: %u", sourceWidth);
914		return;
915	}
916	switch (destWidth) {
917	case 1:
918	case 2:
919	case 4:
920	case 8:
921	case 16:
922	case 32:
923		break;
924	default:
925		mLOG(GBA_BIOS, GAME_ERROR, "Bad BitUnPack destination width: %u", destWidth);
926		return;
927	}
928	uint32_t bias = cpu->memory.load32(cpu, info + 4, 0);
929	uint8_t in = 0;
930	uint32_t out = 0;
931	int bitsRemaining = 0;
932	int bitsEaten = 0;
933	while (sourceLen > 0 || bitsRemaining) {
934		if (!bitsRemaining) {
935			in = cpu->memory.load8(cpu, source, 0);
936			bitsRemaining = 8;
937			++source;
938			--sourceLen;
939		}
940		unsigned scaled = in & ((1 << sourceWidth) - 1);
941		in >>= sourceWidth;
942		if (scaled || bias & 0x80000000) {
943			scaled += bias & 0x7FFFFFFF;
944		}
945		bitsRemaining -= sourceWidth;
946		out |= scaled << bitsEaten;
947		bitsEaten += destWidth;
948		if (bitsEaten == 32) {
949			cpu->memory.store32(cpu, dest, out, 0);
950			bitsEaten = 0;
951			out = 0;
952			dest += 4;
953		}
954	}
955	cpu->gprs[0] = source;
956	cpu->gprs[1] = dest;
957}