b67ef287 |
1 | /* Decode a Game Genie code into an M68000 address/data pair. |
2 | * The Game Genie code is made of the characters |
3 | * ABCDEFGHJKLMNPRSTVWXYZ0123456789 (notice the missing I, O, Q and U). |
4 | * Where A = 00000, B = 00001, C = 00010, ... , on to 9 = 11111. |
5 | * |
6 | * These come out to a very scrambled bit pattern like this: |
7 | * (SCRA-MBLE is just an example) |
8 | * |
9 | * S C R A - M B L E |
10 | * 01111 00010 01110 00000 01011 00001 01010 00100 |
11 | * ijklm nopIJ KLMNO PABCD EFGHd efgha bcQRS TUVWX |
12 | * |
13 | * Our goal is to rearrange that to this: |
14 | * |
15 | * 0000 0101 1001 1100 0100 0100 : 1011 0000 0111 1000 |
16 | * ABCD EFGH IJKL MNOP QRST UVWX : abcd efgh ijkl mnop |
17 | * |
18 | * which in Hexadecimal is 059C44:B078. Simple, huh? ;) |
19 | * |
20 | * So, then, we dutifully change memory location 059C44 to B078! |
21 | * (of course, that's handled by a different source file :) |
22 | */ |
23 | |
efcba75f |
24 | #include "pico_int.h" |
8655fd04 |
25 | #include "memory.h" |
efcba75f |
26 | #include "patch.h" |
b67ef287 |
27 | |
28 | struct patch |
29 | { |
30 | unsigned int addr; |
31 | unsigned short data; |
ed4a2193 |
32 | unsigned char comp; |
b67ef287 |
33 | }; |
34 | |
35 | struct patch_inst *PicoPatches = NULL; |
36 | int PicoPatchCount = 0; |
37 | |
ed4a2193 |
38 | static char genie_chars_md[] = "AaBbCcDdEeFfGgHhJjKkLlMmNnPpRrSsTtVvWwXxYyZz0O1I2233445566778899"; |
b67ef287 |
39 | |
40 | /* genie_decode |
41 | * This function converts a Game Genie code to an address:data pair. |
42 | * The code is given as an 8-character string, like "BJX0SA1C". It need not |
43 | * be null terminated, since only the first 8 characters are taken. It is |
44 | * assumed that the code is already made of valid characters, i.e. there are no |
45 | * Q's, U's, or symbols. If such a character is |
46 | * encountered, the function will return with a warning on stderr. |
47 | * |
48 | * The resulting address:data pair is returned in the struct patch pointed to |
49 | * by result. If an error results, both the address and data will be set to -1. |
50 | */ |
51 | |
ed4a2193 |
52 | static void genie_decode_md(const char* code, struct patch* result) |
b67ef287 |
53 | { |
54 | int i = 0, n; |
55 | char* x; |
56 | |
ed4a2193 |
57 | for(; i < 9; ++i) |
b67ef287 |
58 | { |
ed4a2193 |
59 | /* Skip i=4; it's going to be the separating hyphen */ |
60 | if (i==4) continue; |
61 | |
b67ef287 |
62 | /* If strchr returns NULL, we were given a bad character */ |
ed4a2193 |
63 | if(!(x = strchr(genie_chars_md, code[i]))) |
b67ef287 |
64 | { |
65 | result->addr = -1; result->data = -1; |
66 | return; |
67 | } |
ed4a2193 |
68 | n = (x - genie_chars_md) >> 1; |
b67ef287 |
69 | /* Now, based on which character this is, fit it into the result */ |
70 | switch(i) |
71 | { |
72 | case 0: |
73 | /* ____ ____ ____ ____ ____ ____ : ____ ____ ABCD E___ */ |
74 | result->data |= n << 3; |
75 | break; |
76 | case 1: |
77 | /* ____ ____ DE__ ____ ____ ____ : ____ ____ ____ _ABC */ |
78 | result->data |= n >> 2; |
79 | result->addr |= (n & 3) << 14; |
80 | break; |
81 | case 2: |
82 | /* ____ ____ __AB CDE_ ____ ____ : ____ ____ ____ ____ */ |
83 | result->addr |= n << 9; |
84 | break; |
85 | case 3: |
86 | /* BCDE ____ ____ ___A ____ ____ : ____ ____ ____ ____ */ |
87 | result->addr |= (n & 0xF) << 20 | (n >> 4) << 8; |
88 | break; |
ed4a2193 |
89 | case 5: |
b67ef287 |
90 | /* ____ ABCD ____ ____ ____ ____ : ___E ____ ____ ____ */ |
91 | result->data |= (n & 1) << 12; |
92 | result->addr |= (n >> 1) << 16; |
93 | break; |
ed4a2193 |
94 | case 6: |
b67ef287 |
95 | /* ____ ____ ____ ____ ____ ____ : E___ ABCD ____ ____ */ |
96 | result->data |= (n & 1) << 15 | (n >> 1) << 8; |
97 | break; |
ed4a2193 |
98 | case 7: |
b67ef287 |
99 | /* ____ ____ ____ ____ CDE_ ____ : _AB_ ____ ____ ____ */ |
100 | result->data |= (n >> 3) << 13; |
101 | result->addr |= (n & 7) << 5; |
102 | break; |
ed4a2193 |
103 | case 8: |
b67ef287 |
104 | /* ____ ____ ____ ____ ___A BCDE : ____ ____ ____ ____ */ |
105 | result->addr |= n; |
106 | break; |
107 | } |
108 | /* Go around again */ |
109 | } |
110 | return; |
111 | } |
112 | |
113 | /* "Decode" an address/data pair into a structure. This is for "012345:ABCD" |
114 | * type codes. You're more likely to find Genie codes circulating around, but |
115 | * there's a chance you could come on to one of these. Which is nice, since |
116 | * they're MUCH easier to implement ;) Once again, the input should be depunc- |
117 | * tuated already. */ |
118 | |
119 | static char hex_chars[] = "00112233445566778899AaBbCcDdEeFf"; |
120 | |
ed4a2193 |
121 | static void hex_decode_md(const char *code, struct patch *result) |
b67ef287 |
122 | { |
123 | char *x; |
124 | int i; |
125 | /* 6 digits for address */ |
126 | for(i = 0; i < 6; ++i) |
ed4a2193 |
127 | { |
128 | if(!(x = strchr(hex_chars, code[i]))) |
b67ef287 |
129 | { |
ed4a2193 |
130 | result->addr = result->data = -1; |
131 | return; |
b67ef287 |
132 | } |
ed4a2193 |
133 | result->addr = (result->addr << 4) | ((x - hex_chars) >> 1); |
134 | } |
b67ef287 |
135 | /* 4 digits for data */ |
ed4a2193 |
136 | for(i = 7; i < 11; ++i) |
137 | { |
138 | if(!(x = strchr(hex_chars, code[i]))) |
139 | { |
140 | if (i==8) break; |
141 | result->addr = result->data = -1; |
142 | return; |
143 | } |
144 | result->data = (result->data << 4) | ((x - hex_chars) >> 1); |
145 | } |
146 | } |
147 | |
148 | void genie_decode_ms(const char *code, struct patch *result) |
149 | { |
150 | char *x; |
151 | int i; |
152 | /* 2 digits for data */ |
153 | for(i=0;i<2;++i) |
154 | { |
155 | if(!(x = strchr(hex_chars, code[i]))) |
156 | { |
157 | result->addr = result->data = -1; |
158 | return; |
159 | } |
160 | result->data = (result->data << 4) | ((x - hex_chars) >> 1); |
161 | } |
162 | /* 4 digits for address */ |
163 | for(i=2;i<7;++i) |
164 | { |
165 | /* 4th character is hyphen and can be skipped*/ |
166 | if (i==3) continue; |
167 | if(!(x = strchr(hex_chars, code[i]))) |
168 | { |
169 | result->addr = result->data = -1; |
170 | return; |
171 | } |
172 | result->addr = (result->addr << 4) | ((x - hex_chars) >> 1); |
173 | } |
174 | /* Correct the address */ |
175 | result->addr = ((result->addr >> 4) | (result->addr << 12 & 0xF000)) ^ 0xF000; |
176 | /* Optional: 3 digits for comp */ |
9a570a67 |
177 | if (code[8]=='-'){ |
ed4a2193 |
178 | for(i=8;i<11;++i) |
b67ef287 |
179 | { |
ed4a2193 |
180 | if (i==9) continue; /* 2nd character is ignored */ |
b67ef287 |
181 | if(!(x = strchr(hex_chars, code[i]))) |
182 | { |
183 | result->addr = result->data = -1; |
184 | return; |
185 | } |
ed4a2193 |
186 | result->comp = (result->comp << 4) | ((x - hex_chars) >> 1); |
187 | } |
188 | /* Correct the comp */ |
189 | result->comp = ((result->comp >> 2) | ((result->comp << 6) & 0xC0)) ^ 0xBA; |
190 | } |
191 | } |
192 | |
193 | void ar_decode_ms(const char *code, struct patch *result){ |
194 | char *x; |
195 | int i; |
196 | /* 2 digits of padding*/ |
197 | /* 4 digits for address */ |
198 | for(i=2;i<7;++i) |
199 | { |
200 | /* 5th character is hyphen and can be skipped*/ |
201 | if (i==4) continue; |
202 | if(!(x = strchr(hex_chars, code[i]))) |
203 | { |
204 | result->addr = result->data = -1; |
205 | return; |
206 | } |
207 | result->addr = (result->addr << 4) | ((x - hex_chars) >> 1); |
208 | } |
209 | /* 2 digits for data */ |
210 | for(i=7;i<9;++i) |
211 | { |
212 | if(!(x = strchr(hex_chars, code[i]))) |
213 | { |
214 | result->addr = result->data = -1; |
215 | return; |
216 | } |
217 | result->data = (result->data << 4) | ((x - hex_chars) >> 1); |
218 | } |
219 | } |
220 | |
221 | void fusion_ram_decode(const char *code, struct patch *result){ |
222 | char *x; |
223 | int i; |
224 | /* 4 digits for address */ |
225 | for(i=0;i<4;++i) |
226 | { |
227 | if(!(x = strchr(hex_chars, code[i]))) |
228 | { |
229 | result->addr = result->data = -1; |
230 | return; |
231 | } |
232 | result->addr = (result->addr << 4) | ((x - hex_chars) >> 1); |
233 | } |
234 | /* Skip the ':' */ |
235 | /* 2 digits for data */ |
236 | for(i=5;i<7;++i) |
237 | { |
238 | if(!(x = strchr(hex_chars, code[i]))) |
239 | { |
240 | result->addr = result->data = -1; |
241 | return; |
242 | } |
243 | result->data = (result->data << 4) | ((x - hex_chars) >> 1); |
244 | } |
245 | } |
246 | |
247 | void fusion_rom_decode(const char *code, struct patch *result){ |
248 | char *x; |
249 | int i; |
250 | /* 2 digits for comp */ |
251 | for(i=0;i<2;++i) |
252 | { |
253 | if(!(x = strchr(hex_chars, code[i]))) |
254 | { |
255 | result->addr = result->data = -1; |
256 | return; |
257 | } |
258 | result->comp = (result->comp << 4) | ((x - hex_chars) >> 1); |
259 | } |
260 | /* 4 digits for address */ |
261 | for(i=2;i<6;++i) |
262 | { |
263 | if(!(x = strchr(hex_chars, code[i]))) |
264 | { |
265 | result->addr = result->data = -1; |
266 | return; |
b67ef287 |
267 | } |
ed4a2193 |
268 | result->addr = (result->addr << 4) | ((x - hex_chars) >> 1); |
269 | } |
270 | /* 2 digits for data */ |
271 | for(i=7;i<9;++i) |
272 | { |
273 | if(!(x = strchr(hex_chars, code[i]))) |
274 | { |
275 | result->addr = result->data = -1; |
276 | return; |
277 | } |
278 | result->data = (result->data << 4) | ((x - hex_chars) >> 1); |
279 | } |
b67ef287 |
280 | } |
281 | |
282 | /* THIS is the function you call from the MegaDrive or whatever. This figures |
283 | * out whether it's a genie or hex code, depunctuates it, and calls the proper |
284 | * decoder. */ |
8655fd04 |
285 | void decode(const char* code, struct patch* result) |
b67ef287 |
286 | { |
ed4a2193 |
287 | int len = strlen(code); |
b67ef287 |
288 | |
289 | /* Initialize the result */ |
ed4a2193 |
290 | result->addr = result->data = result->comp = 0; |
b67ef287 |
291 | |
ed4a2193 |
292 | if(!(PicoAHW & PAHW_SMS)) |
b67ef287 |
293 | { |
ed4a2193 |
294 | //If Genesis |
b67ef287 |
295 | |
ed4a2193 |
296 | //Game Genie |
b67ef287 |
297 | if(len == 9 && code[4] == '-') |
298 | { |
ed4a2193 |
299 | genie_decode_md(code, result); |
b67ef287 |
300 | return; |
301 | } |
302 | |
ed4a2193 |
303 | //Master |
304 | else if(len >=9 && code[6] == ':') |
305 | { |
306 | hex_decode_md(code, result); |
307 | } |
308 | |
309 | else |
310 | { |
311 | goto bad_code; |
312 | } |
313 | } else { |
314 | //If Master System |
b67ef287 |
315 | |
ed4a2193 |
316 | //Genie |
9a570a67 |
317 | if(len >= 7 && code[3] == '-') |
ed4a2193 |
318 | { |
319 | genie_decode_ms(code, result); |
320 | } |
b67ef287 |
321 | |
ed4a2193 |
322 | //AR |
323 | else if(len == 9 && code[4] == '-') |
324 | { |
325 | ar_decode_ms(code, result); |
326 | } |
b67ef287 |
327 | |
ed4a2193 |
328 | //Fusion RAM |
329 | else if(len == 7 && code[4] == ':') |
330 | { |
331 | fusion_ram_decode(code, result); |
332 | } |
b67ef287 |
333 | |
ed4a2193 |
334 | //Fusion ROM |
335 | else if(len == 9 && code[6] == ':') |
336 | { |
337 | fusion_rom_decode(code, result); |
338 | } |
b67ef287 |
339 | |
ed4a2193 |
340 | else |
341 | { |
342 | goto bad_code; |
343 | } |
344 | |
345 | //Convert RAM address space to Genesis location. |
346 | if (result->addr>=0xC000) |
347 | result->addr= 0xFF0000 | (0x1FFF & result->addr); |
348 | } |
b67ef287 |
349 | |
ed4a2193 |
350 | return; |
b67ef287 |
351 | |
ed4a2193 |
352 | bad_code: |
b67ef287 |
353 | result->data = result->addr = -1; |
354 | return; |
355 | } |
356 | |
b67ef287 |
357 | void PicoPatchUnload(void) |
358 | { |
359 | if (PicoPatches != NULL) |
360 | { |
361 | free(PicoPatches); |
362 | PicoPatches = NULL; |
363 | } |
364 | PicoPatchCount = 0; |
365 | } |
366 | |
367 | int PicoPatchLoad(const char *fname) |
368 | { |
369 | FILE *f; |
370 | char buff[256]; |
371 | struct patch pt; |
372 | int array_len = 0; |
373 | |
374 | PicoPatchUnload(); |
375 | |
376 | f = fopen(fname, "r"); |
377 | if (f == NULL) |
378 | { |
379 | return -1; |
380 | } |
381 | |
382 | while (fgets(buff, sizeof(buff), f)) |
383 | { |
384 | int llen, clen; |
385 | |
386 | llen = strlen(buff); |
387 | for (clen = 0; clen < llen; clen++) |
ee2a3bdf |
388 | if (isspace_(buff[clen])) |
389 | break; |
b67ef287 |
390 | buff[clen] = 0; |
391 | |
392 | if (clen > 11 || clen < 8) |
393 | continue; |
394 | |
395 | decode(buff, &pt); |
396 | if (pt.addr == (unsigned int)-1 || pt.data == (unsigned short)-1) |
397 | continue; |
398 | |
399 | /* code was good, add it */ |
400 | if (array_len < PicoPatchCount + 1) |
401 | { |
402 | void *ptr; |
403 | array_len *= 2; |
404 | array_len++; |
405 | ptr = realloc(PicoPatches, array_len * sizeof(PicoPatches[0])); |
406 | if (ptr == NULL) break; |
407 | PicoPatches = ptr; |
408 | } |
409 | strcpy(PicoPatches[PicoPatchCount].code, buff); |
410 | /* strip */ |
411 | for (clen++; clen < llen; clen++) |
ee2a3bdf |
412 | if (!isspace_(buff[clen])) |
413 | break; |
b67ef287 |
414 | for (llen--; llen > 0; llen--) |
ee2a3bdf |
415 | if (!isspace_(buff[llen])) |
416 | break; |
b67ef287 |
417 | buff[llen+1] = 0; |
418 | strncpy(PicoPatches[PicoPatchCount].name, buff + clen, 51); |
419 | PicoPatches[PicoPatchCount].name[51] = 0; |
420 | PicoPatches[PicoPatchCount].active = 0; |
421 | PicoPatches[PicoPatchCount].addr = pt.addr; |
422 | PicoPatches[PicoPatchCount].data = pt.data; |
423 | PicoPatches[PicoPatchCount].data_old = 0; |
424 | PicoPatchCount++; |
425 | // fprintf(stderr, "loaded patch #%i: %06x:%04x \"%s\"\n", PicoPatchCount-1, pt.addr, pt.data, |
426 | // PicoPatches[PicoPatchCount-1].name); |
427 | } |
428 | fclose(f); |
429 | |
430 | return 0; |
431 | } |
432 | |
433 | /* to be called when the Rom is loaded and byteswapped */ |
434 | void PicoPatchPrepare(void) |
435 | { |
ed4a2193 |
436 | int i; |
437 | int addr; |
b67ef287 |
438 | |
ed4a2193 |
439 | for (i = 0; i < PicoPatchCount; i++) |
440 | { |
441 | addr=PicoPatches[i].addr; |
442 | addr &= ~1; |
443 | if (addr < Pico.romsize) |
444 | PicoPatches[i].data_old = *(unsigned short *)(Pico.rom + addr); |
445 | else |
446 | { |
447 | if(!(PicoAHW & PAHW_SMS)) |
448 | PicoPatches[i].data_old = (unsigned short) m68k_read16(addr); |
449 | else |
450 | ; // wrong: PicoPatches[i].data_old = (unsigned char) PicoRead8_z80(addr); |
451 | } |
452 | if (strstr(PicoPatches[i].name, "AUTO")) |
453 | PicoPatches[i].active = 1; |
454 | } |
b67ef287 |
455 | } |
456 | |
457 | void PicoPatchApply(void) |
458 | { |
ed4a2193 |
459 | int i, u; |
460 | unsigned int addr; |
b67ef287 |
461 | |
ed4a2193 |
462 | for (i = 0; i < PicoPatchCount; i++) |
463 | { |
464 | addr = PicoPatches[i].addr; |
465 | |
466 | if (addr < Pico.romsize) |
467 | { |
468 | if (PicoPatches[i].active) |
469 | { |
470 | if (!(PicoAHW & PAHW_SMS)) |
471 | *(unsigned short *)(Pico.rom + addr) = PicoPatches[i].data; |
472 | else if (!PicoPatches[i].comp || PicoPatches[i].comp == *(char *)(Pico.rom + addr)) |
473 | *(char *)(Pico.rom + addr) = (char) PicoPatches[i].data; |
474 | } |
475 | else |
476 | { |
477 | // if current addr is not patched by older patch, write back original val |
478 | for (u = 0; u < i; u++) |
479 | if (PicoPatches[u].addr == addr) break; |
480 | if (u == i) |
b67ef287 |
481 | { |
ed4a2193 |
482 | if (!(PicoAHW & PAHW_SMS)) |
483 | *(unsigned short *)(Pico.rom + addr) = PicoPatches[i].data_old; |
484 | else |
485 | *(char *)(Pico.rom + addr) = (char) PicoPatches[i].data_old; |
b67ef287 |
486 | } |
ed4a2193 |
487 | } |
488 | // fprintf(stderr, "patched %i: %06x:%04x\n", PicoPatches[i].active, addr, |
489 | // *(unsigned short *)(Pico.rom + addr)); |
490 | } |
491 | else |
492 | { |
493 | if (PicoPatches[i].active) |
494 | { |
495 | if (!(PicoAHW & PAHW_SMS)) |
496 | m68k_write16(addr,PicoPatches[i].data); |
497 | else |
498 | ;// wrong: PicoWrite8_z80(addr,PicoPatches[i].data); |
499 | } |
500 | else |
501 | { |
502 | // if current addr is not patched by older patch, write back original val |
503 | for (u = 0; u < i; u++) |
504 | if (PicoPatches[u].addr == addr) break; |
505 | if (u == i) |
506 | { |
507 | if (!(PicoAHW & PAHW_SMS)) |
508 | m68k_write16(PicoPatches[i].addr,PicoPatches[i].data_old); |
509 | else |
510 | ;// wrong: PicoWrite8_z80(PicoPatches[i].addr,PicoPatches[i].data_old); |
511 | } |
512 | } |
513 | } |
514 | } |
b67ef287 |
515 | } |
516 | |