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 "bios.h"
7
8#include "gba/gba.h"
9#include "gba/io.h"
10#include "gba/memory.h"
11#include "isa-inlines.h"
12
13const uint32_t GBA_BIOS_CHECKSUM = 0xBAAE187F;
14const uint32_t GBA_DS_BIOS_CHECKSUM = 0xBAAE1880;
15
16static void _unLz77(struct GBA* gba, int width);
17static void _unHuffman(struct GBA* gba);
18static void _unRl(struct GBA* gba, int width);
19static void _unFilter(struct GBA* gba, int inwidth, int outwidth);
20
21static void _SoftReset(struct GBA* gba) {
22 struct ARMCore* cpu = gba->cpu;
23 ARMSetPrivilegeMode(cpu, MODE_IRQ);
24 cpu->spsr.packed = 0;
25 cpu->gprs[ARM_LR] = 0;
26 cpu->gprs[ARM_SP] = SP_BASE_IRQ;
27 ARMSetPrivilegeMode(cpu, MODE_SUPERVISOR);
28 cpu->spsr.packed = 0;
29 cpu->gprs[ARM_LR] = 0;
30 cpu->gprs[ARM_SP] = SP_BASE_SUPERVISOR;
31 ARMSetPrivilegeMode(cpu, MODE_SYSTEM);
32 cpu->gprs[ARM_LR] = 0;
33 cpu->gprs[ARM_SP] = SP_BASE_SYSTEM;
34 int8_t flag = ((int8_t*) gba->memory.iwram)[0x7FFA];
35 memset(((int8_t*) gba->memory.iwram) + SIZE_WORKING_IRAM - 0x200, 0, 0x200);
36 if (flag) {
37 cpu->gprs[ARM_PC] = BASE_WORKING_RAM;
38 } else {
39 cpu->gprs[ARM_PC] = BASE_CART0;
40 }
41 _ARMSetMode(cpu, MODE_ARM);
42 int currentCycles = 0;
43 ARM_WRITE_PC;
44}
45
46static void _RegisterRamReset(struct GBA* gba) {
47 uint32_t registers = gba->cpu->gprs[0];
48 struct ARMCore* cpu = gba->cpu;
49 cpu->memory.store16(cpu, BASE_IO | REG_DISPCNT, 0x0080, 0);
50 if (registers & 0x01) {
51 memset(gba->memory.wram, 0, SIZE_WORKING_RAM);
52 }
53 if (registers & 0x02) {
54 memset(gba->memory.iwram, 0, SIZE_WORKING_IRAM - 0x200);
55 }
56 if (registers & 0x04) {
57 memset(gba->video.palette, 0, SIZE_PALETTE_RAM);
58 }
59 if (registers & 0x08) {
60 memset(gba->video.renderer->vram, 0, SIZE_VRAM);
61 }
62 if (registers & 0x10) {
63 memset(gba->video.oam.raw, 0, SIZE_OAM);
64 }
65 if (registers & 0x20) {
66 GBALog(gba, GBA_LOG_STUB, "RegisterRamReset on SIO unimplemented");
67 }
68 if (registers & 0x40) {
69 GBALog(gba, GBA_LOG_STUB, "RegisterRamReset on Audio unimplemented");
70 }
71 if (registers & 0x80) {
72 GBALog(gba, GBA_LOG_STUB, "RegisterRamReset on IO unimplemented");
73 }
74}
75
76static void _BgAffineSet(struct GBA* gba) {
77 struct ARMCore* cpu = gba->cpu;
78 int i = cpu->gprs[2];
79 float ox, oy;
80 float cx, cy;
81 float sx, sy;
82 float theta;
83 int offset = cpu->gprs[0];
84 int destination = cpu->gprs[1];
85 float a, b, c, d;
86 float rx, ry;
87 while (i--) {
88 // [ sx 0 0 ] [ cos(theta) -sin(theta) 0 ] [ 1 0 cx - ox ] [ A B rx ]
89 // [ 0 sy 0 ] * [ sin(theta) cos(theta) 0 ] * [ 0 1 cy - oy ] = [ C D ry ]
90 // [ 0 0 1 ] [ 0 0 1 ] [ 0 0 1 ] [ 0 0 1 ]
91 ox = (int32_t) cpu->memory.load32(cpu, offset, 0) / 256.f;
92 oy = (int32_t) cpu->memory.load32(cpu, offset + 4, 0) / 256.f;
93 cx = (int16_t) cpu->memory.load16(cpu, offset + 8, 0);
94 cy = (int16_t) cpu->memory.load16(cpu, offset + 10, 0);
95 sx = (int16_t) cpu->memory.load16(cpu, offset + 12, 0) / 256.f;
96 sy = (int16_t) cpu->memory.load16(cpu, offset + 14, 0) / 256.f;
97 theta = (cpu->memory.load16(cpu, offset + 16, 0) >> 8) / 128.f * M_PI;
98 offset += 20;
99 // Rotation
100 a = d = cosf(theta);
101 b = c = sinf(theta);
102 // Scale
103 a *= sx;
104 b *= -sx;
105 c *= sy;
106 d *= sy;
107 // Translate
108 rx = ox - (a * cx + b * cy);
109 ry = oy - (c * cx + d * cy);
110 cpu->memory.store16(cpu, destination, a * 256, 0);
111 cpu->memory.store16(cpu, destination + 2, b * 256, 0);
112 cpu->memory.store16(cpu, destination + 4, c * 256, 0);
113 cpu->memory.store16(cpu, destination + 6, d * 256, 0);
114 cpu->memory.store32(cpu, destination + 8, rx * 256, 0);
115 cpu->memory.store32(cpu, destination + 12, ry * 256, 0);
116 destination += 16;
117 }
118}
119
120static void _ObjAffineSet(struct GBA* gba) {
121 struct ARMCore* cpu = gba->cpu;
122 int i = cpu->gprs[2];
123 float sx, sy;
124 float theta;
125 int offset = cpu->gprs[0];
126 int destination = cpu->gprs[1];
127 int diff = cpu->gprs[3];
128 float a, b, c, d;
129 while (i--) {
130 // [ sx 0 ] [ cos(theta) -sin(theta) ] [ A B ]
131 // [ 0 sy ] * [ sin(theta) cos(theta) ] = [ C D ]
132 sx = (int16_t) cpu->memory.load16(cpu, offset, 0) / 256.f;
133 sy = (int16_t) cpu->memory.load16(cpu, offset + 2, 0) / 256.f;
134 theta = (cpu->memory.load16(cpu, offset + 4, 0) >> 8) / 128.f * M_PI;
135 offset += 8;
136 // Rotation
137 a = d = cosf(theta);
138 b = c = sinf(theta);
139 // Scale
140 a *= sx;
141 b *= -sx;
142 c *= sy;
143 d *= sy;
144 cpu->memory.store16(cpu, destination, a * 256, 0);
145 cpu->memory.store16(cpu, destination + diff, b * 256, 0);
146 cpu->memory.store16(cpu, destination + diff * 2, c * 256, 0);
147 cpu->memory.store16(cpu, destination + diff * 3, d * 256, 0);
148 destination += diff * 4;
149 }
150}
151
152static void _MidiKey2Freq(struct GBA* gba) {
153 struct ARMCore* cpu = gba->cpu;
154 uint32_t key = cpu->memory.load32(cpu, cpu->gprs[0] + 4, 0);
155 cpu->gprs[0] = key / powf(2, (180.f - cpu->gprs[1] - cpu->gprs[2] / 256.f) / 12.f);
156}
157
158static void _Div(struct GBA* gba, int32_t num, int32_t denom) {
159 struct ARMCore* cpu = gba->cpu;
160 if (denom != 0) {
161 div_t result = div(num, denom);
162 cpu->gprs[0] = result.quot;
163 cpu->gprs[1] = result.rem;
164 cpu->gprs[3] = abs(result.quot);
165 } else {
166 GBALog(gba, GBA_LOG_GAME_ERROR, "Attempting to divide %i by zero!", num);
167 // If abs(num) > 1, this should hang, but that would be painful to
168 // emulate in HLE, and no game will get into a state where it hangs...
169 cpu->gprs[0] = (num < 0) ? -1 : 1;
170 cpu->gprs[1] = num;
171 cpu->gprs[3] = 1;
172 }
173}
174
175void GBASwi16(struct ARMCore* cpu, int immediate) {
176 struct GBA* gba = (struct GBA*) cpu->master;
177 GBALog(gba, GBA_LOG_SWI, "SWI: %02X r0: %08X r1: %08X r2: %08X r3: %08X",
178 immediate, cpu->gprs[0], cpu->gprs[1], cpu->gprs[2], cpu->gprs[3]);
179
180 if (gba->memory.fullBios) {
181 ARMRaiseSWI(cpu);
182 return;
183 }
184 switch (immediate) {
185 case 0x0:
186 _SoftReset(gba);
187 break;
188 case 0x1:
189 _RegisterRamReset(gba);
190 break;
191 case 0x2:
192 GBAHalt(gba);
193 break;
194 case 0x3:
195 GBAStop(gba);
196 break;
197 case 0x05:
198 // VBlankIntrWait
199 // Fall through:
200 case 0x04:
201 // IntrWait
202 ARMRaiseSWI(cpu);
203 break;
204 case 0x6:
205 _Div(gba, cpu->gprs[0], cpu->gprs[1]);
206 break;
207 case 0x7:
208 _Div(gba, cpu->gprs[1], cpu->gprs[0]);
209 break;
210 case 0x8:
211 cpu->gprs[0] = sqrt(cpu->gprs[0]);
212 break;
213 case 0xA:
214 cpu->gprs[0] = atan2f(cpu->gprs[1] / 16384.f, cpu->gprs[0] / 16384.f) / (2 * M_PI) * 0x10000;
215 break;
216 case 0xB:
217 case 0xC:
218 if (cpu->gprs[0] >> BASE_OFFSET == REGION_BIOS) {
219 GBALog(gba, GBA_LOG_GAME_ERROR, "Cannot CpuSet from BIOS");
220 return;
221 }
222 ARMRaiseSWI(cpu);
223 break;
224 case 0xD:
225 cpu->gprs[0] = GBA_BIOS_CHECKSUM;
226 cpu->gprs[1] = 1;
227 cpu->gprs[3] = SIZE_BIOS;
228 break;
229 case 0xE:
230 _BgAffineSet(gba);
231 break;
232 case 0xF:
233 _ObjAffineSet(gba);
234 break;
235 case 0x11:
236 case 0x12:
237 if (cpu->gprs[0] < BASE_WORKING_RAM) {
238 GBALog(gba, GBA_LOG_GAME_ERROR, "Bad LZ77 source");
239 break;
240 }
241 switch (cpu->gprs[1] >> BASE_OFFSET) {
242 default:
243 GBALog(gba, GBA_LOG_GAME_ERROR, "Bad LZ77 destination");
244 // Fall through
245 case REGION_WORKING_RAM:
246 case REGION_WORKING_IRAM:
247 case REGION_VRAM:
248 _unLz77(gba, immediate == 0x11 ? 1 : 2);
249 break;
250 }
251 break;
252 case 0x13:
253 if (cpu->gprs[0] < BASE_WORKING_RAM) {
254 GBALog(gba, GBA_LOG_GAME_ERROR, "Bad Huffman source");
255 break;
256 }
257 switch (cpu->gprs[1] >> BASE_OFFSET) {
258 default:
259 GBALog(gba, GBA_LOG_GAME_ERROR, "Bad Huffman destination");
260 // Fall through
261 case REGION_WORKING_RAM:
262 case REGION_WORKING_IRAM:
263 case REGION_VRAM:
264 _unHuffman(gba);
265 break;
266 }
267 break;
268 case 0x14:
269 case 0x15:
270 if (cpu->gprs[0] < BASE_WORKING_RAM) {
271 GBALog(gba, GBA_LOG_GAME_ERROR, "Bad RL source");
272 break;
273 }
274 switch (cpu->gprs[1] >> BASE_OFFSET) {
275 default:
276 GBALog(gba, GBA_LOG_GAME_ERROR, "Bad RL destination");
277 // Fall through
278 case REGION_WORKING_RAM:
279 case REGION_WORKING_IRAM:
280 case REGION_VRAM:
281 _unRl(gba, immediate == 0x14 ? 1 : 2);
282 break;
283 }
284 break;
285 case 0x16:
286 case 0x17:
287 case 0x18:
288 if (cpu->gprs[0] < BASE_WORKING_RAM) {
289 GBALog(gba, GBA_LOG_GAME_ERROR, "Bad UnFilter source");
290 break;
291 }
292 switch (cpu->gprs[1] >> BASE_OFFSET) {
293 default:
294 GBALog(gba, GBA_LOG_GAME_ERROR, "Bad UnFilter destination");
295 // Fall through
296 case REGION_WORKING_RAM:
297 case REGION_WORKING_IRAM:
298 case REGION_VRAM:
299 _unFilter(gba, immediate == 0x18 ? 2 : 1, immediate == 0x16 ? 1 : 2);
300 break;
301 }
302 break;
303 case 0x19:
304 // SoundBias is mostly meaningless here
305 GBALog(gba, GBA_LOG_STUB, "Stub software interrupt: SoundBias (19)");
306 break;
307 case 0x1F:
308 _MidiKey2Freq(gba);
309 break;
310 default:
311 GBALog(gba, GBA_LOG_STUB, "Stub software interrupt: %02X", immediate);
312 }
313 gba->memory.biosPrefetch = 0xE3A02004;
314}
315
316void GBASwi32(struct ARMCore* cpu, int immediate) {
317 GBASwi16(cpu, immediate >> 16);
318}
319
320uint32_t GBAChecksum(uint32_t* memory, size_t size) {
321 size_t i;
322 uint32_t sum = 0;
323 for (i = 0; i < size; i += 4) {
324 sum += memory[i >> 2];
325 }
326 return sum;
327}
328
329static void _unLz77(struct GBA* gba, int width) {
330 struct ARMCore* cpu = gba->cpu;
331 uint32_t source = cpu->gprs[0];
332 uint32_t dest = cpu->gprs[1];
333 int remaining = (cpu->memory.load32(cpu, source, 0) & 0xFFFFFF00) >> 8;
334 // We assume the signature byte (0x10) is correct
335 int blockheader = 0; // Some compilers warn if this isn't set, even though it's trivially provably always set
336 source += 4;
337 int blocksRemaining = 0;
338 uint32_t disp;
339 int bytes;
340 int byte;
341 int halfword = 0;
342 while (remaining > 0) {
343 if (blocksRemaining) {
344 if (blockheader & 0x80) {
345 // Compressed
346 int block = cpu->memory.load8(cpu, source + 1, 0) | (cpu->memory.load8(cpu, source, 0) << 8);
347 source += 2;
348 disp = dest - (block & 0x0FFF) - 1;
349 bytes = (block >> 12) + 3;
350 while (bytes-- && remaining) {
351 --remaining;
352 if (width == 2) {
353 byte = (int16_t) cpu->memory.load16(cpu, disp & ~1, 0);
354 if (dest & 1) {
355 byte >>= (disp & 1) * 8;
356 halfword |= byte << 8;
357 cpu->memory.store16(cpu, dest ^ 1, halfword, 0);
358 } else {
359 byte >>= (disp & 1) * 8;
360 halfword = byte & 0xFF;
361 }
362 } else {
363 byte = cpu->memory.load8(cpu, disp, 0);
364 cpu->memory.store8(cpu, dest, byte, 0);
365 }
366 ++disp;
367 ++dest;
368 }
369 } else {
370 // Uncompressed
371 byte = cpu->memory.load8(cpu, source, 0);
372 ++source;
373 if (width == 2) {
374 if (dest & 1) {
375 halfword |= byte << 8;
376 cpu->memory.store16(cpu, dest ^ 1, halfword, 0);
377 } else {
378 halfword = byte;
379 }
380 } else {
381 cpu->memory.store8(cpu, dest, byte, 0);
382 }
383 ++dest;
384 --remaining;
385 }
386 blockheader <<= 1;
387 --blocksRemaining;
388 } else {
389 blockheader = cpu->memory.load8(cpu, source, 0);
390 ++source;
391 blocksRemaining = 8;
392 }
393 }
394 cpu->gprs[0] = source;
395 cpu->gprs[1] = dest;
396 cpu->gprs[3] = 0;
397}
398
399DECL_BITFIELD(HuffmanNode, uint8_t);
400DECL_BITS(HuffmanNode, Offset, 0, 6);
401DECL_BIT(HuffmanNode, RTerm, 6);
402DECL_BIT(HuffmanNode, LTerm, 7);
403
404static void _unHuffman(struct GBA* gba) {
405 struct ARMCore* cpu = gba->cpu;
406 uint32_t source = cpu->gprs[0] & 0xFFFFFFFC;
407 uint32_t dest = cpu->gprs[1];
408 uint32_t header = cpu->memory.load32(cpu, source, 0);
409 int remaining = header >> 8;
410 int bits = header & 0xF;
411 if (bits == 0) {
412 GBALog(gba, GBA_LOG_GAME_ERROR, "Invalid Huffman bits");
413 bits = 8;
414 }
415 if (32 % bits || bits == 1) {
416 GBALog(gba, GBA_LOG_STUB, "Unimplemented unaligned Huffman");
417 return;
418 }
419 // We assume the signature byte (0x20) is correct
420 int treesize = (cpu->memory.load8(cpu, source + 4, 0) << 1) + 1;
421 int block = 0;
422 uint32_t treeBase = source + 5;
423 source += 5 + treesize;
424 uint32_t nPointer = treeBase;
425 HuffmanNode node;
426 int bitsRemaining;
427 int readBits;
428 int bitsSeen = 0;
429 node = cpu->memory.load8(cpu, nPointer, 0);
430 while (remaining > 0) {
431 uint32_t bitstream = cpu->memory.load32(cpu, source, 0);
432 source += 4;
433 for (bitsRemaining = 32; bitsRemaining > 0 && remaining > 0; --bitsRemaining, bitstream <<= 1) {
434 uint32_t next = (nPointer & ~1) + HuffmanNodeGetOffset(node) * 2 + 2;
435 if (bitstream & 0x80000000) {
436 // Go right
437 if (HuffmanNodeIsRTerm(node)) {
438 readBits = cpu->memory.load8(cpu, next + 1, 0);
439 } else {
440 nPointer = next + 1;
441 node = cpu->memory.load8(cpu, nPointer, 0);
442 continue;
443 }
444 } else {
445 // Go left
446 if (HuffmanNodeIsLTerm(node)) {
447 readBits = cpu->memory.load8(cpu, next, 0);
448 } else {
449 nPointer = next;
450 node = cpu->memory.load8(cpu, nPointer, 0);
451 continue;
452 }
453 }
454
455 block |= (readBits & ((1 << bits) - 1)) << bitsSeen;
456 bitsSeen += bits;
457 nPointer = treeBase;
458 node = cpu->memory.load8(cpu, nPointer, 0);
459 if (bitsSeen == 32) {
460 bitsSeen = 0;
461 cpu->memory.store32(cpu, dest, block, 0);
462 dest += 4;
463 remaining -= 4;
464 block = 0;
465 }
466 }
467 }
468 cpu->gprs[0] = source;
469 cpu->gprs[1] = dest;
470}
471
472static void _unRl(struct GBA* gba, int width) {
473 struct ARMCore* cpu = gba->cpu;
474 uint32_t source = cpu->gprs[0] & 0xFFFFFFFC;
475 int remaining = (cpu->memory.load32(cpu, source, 0) & 0xFFFFFF00) >> 8;
476 int padding = (4 - remaining) & 0x3;
477 // We assume the signature byte (0x30) is correct
478 int blockheader;
479 int block;
480 source += 4;
481 uint32_t dest = cpu->gprs[1];
482 int halfword = 0;
483 while (remaining > 0) {
484 blockheader = cpu->memory.load8(cpu, source, 0);
485 ++source;
486 if (blockheader & 0x80) {
487 // Compressed
488 blockheader &= 0x7F;
489 blockheader += 3;
490 block = cpu->memory.load8(cpu, source, 0);
491 ++source;
492 while (blockheader-- && remaining) {
493 --remaining;
494 if (width == 2) {
495 if (dest & 1) {
496 halfword |= block << 8;
497 cpu->memory.store16(cpu, dest ^ 1, halfword, 0);
498 } else {
499 halfword = block;
500 }
501 } else {
502 cpu->memory.store8(cpu, dest, block, 0);
503 }
504 ++dest;
505 }
506 } else {
507 // Uncompressed
508 blockheader++;
509 while (blockheader-- && remaining) {
510 --remaining;
511 int byte = cpu->memory.load8(cpu, source, 0);
512 ++source;
513 if (width == 2) {
514 if (dest & 1) {
515 halfword |= byte << 8;
516 cpu->memory.store16(cpu, dest ^ 1, halfword, 0);
517 } else {
518 halfword = byte;
519 }
520 } else {
521 cpu->memory.store8(cpu, dest, byte, 0);
522 }
523 ++dest;
524 }
525 }
526 }
527 if (width == 2) {
528 if (dest & 1) {
529 --padding;
530 ++dest;
531 }
532 for (; padding > 0; padding -= 2, dest += 2) {
533 cpu->memory.store16(cpu, dest, 0, 0);
534 }
535 } else {
536 while (padding--) {
537 cpu->memory.store8(cpu, dest, 0, 0);
538 ++dest;
539 }
540 }
541 cpu->gprs[0] = source;
542 cpu->gprs[1] = dest;
543}
544
545static void _unFilter(struct GBA* gba, int inwidth, int outwidth) {
546 struct ARMCore* cpu = gba->cpu;
547 uint32_t source = cpu->gprs[0] & 0xFFFFFFFC;
548 uint32_t dest = cpu->gprs[1];
549 uint32_t header = cpu->memory.load32(cpu, source, 0);
550 int remaining = header >> 8;
551 // We assume the signature nybble (0x8) is correct
552 uint16_t halfword = 0;
553 uint16_t old = 0;
554 source += 4;
555 while (remaining > 0) {
556 uint16_t new;
557 if (inwidth == 1) {
558 new = cpu->memory.load8(cpu, source, 0);
559 } else {
560 new = cpu->memory.load16(cpu, source, 0);
561 }
562 new += old;
563 if (outwidth > inwidth) {
564 halfword >>= 8;
565 halfword |= (new << 8);
566 if (source & 1) {
567 cpu->memory.store16(cpu, dest, halfword, 0);
568 dest += outwidth;
569 remaining -= outwidth;
570 }
571 } else if (outwidth == 1) {
572 cpu->memory.store8(cpu, dest, new, 0);
573 dest += outwidth;
574 remaining -= outwidth;
575 } else {
576 cpu->memory.store16(cpu, dest, new, 0);
577 dest += outwidth;
578 remaining -= outwidth;
579 }
580 old = new;
581 source += inwidth;
582 }
583 cpu->gprs[0] = source;
584 cpu->gprs[1] = dest;
585}