dasm_mips.h (12327B)
1 /* 2 ** DynASM MIPS encoding engine. 3 ** Copyright (C) 2005-2016 Mike Pall. All rights reserved. 4 ** Released under the MIT license. See dynasm.lua for full copyright notice. 5 */ 6 7 #include <stddef.h> 8 #include <stdarg.h> 9 #include <string.h> 10 #include <stdlib.h> 11 12 #define DASM_ARCH "mips" 13 14 #ifndef DASM_EXTERN 15 #define DASM_EXTERN(a,b,c,d) 0 16 #endif 17 18 /* Action definitions. */ 19 enum { 20 DASM_STOP, DASM_SECTION, DASM_ESC, DASM_REL_EXT, 21 /* The following actions need a buffer position. */ 22 DASM_ALIGN, DASM_REL_LG, DASM_LABEL_LG, 23 /* The following actions also have an argument. */ 24 DASM_REL_PC, DASM_LABEL_PC, DASM_IMM, DASM_IMMS, 25 DASM__MAX 26 }; 27 28 /* Maximum number of section buffer positions for a single dasm_put() call. */ 29 #define DASM_MAXSECPOS 25 30 31 /* DynASM encoder status codes. Action list offset or number are or'ed in. */ 32 #define DASM_S_OK 0x00000000 33 #define DASM_S_NOMEM 0x01000000 34 #define DASM_S_PHASE 0x02000000 35 #define DASM_S_MATCH_SEC 0x03000000 36 #define DASM_S_RANGE_I 0x11000000 37 #define DASM_S_RANGE_SEC 0x12000000 38 #define DASM_S_RANGE_LG 0x13000000 39 #define DASM_S_RANGE_PC 0x14000000 40 #define DASM_S_RANGE_REL 0x15000000 41 #define DASM_S_UNDEF_LG 0x21000000 42 #define DASM_S_UNDEF_PC 0x22000000 43 44 /* Macros to convert positions (8 bit section + 24 bit index). */ 45 #define DASM_POS2IDX(pos) ((pos)&0x00ffffff) 46 #define DASM_POS2BIAS(pos) ((pos)&0xff000000) 47 #define DASM_SEC2POS(sec) ((sec)<<24) 48 #define DASM_POS2SEC(pos) ((pos)>>24) 49 #define DASM_POS2PTR(D, pos) (D->sections[DASM_POS2SEC(pos)].rbuf + (pos)) 50 51 /* Action list type. */ 52 typedef const unsigned int *dasm_ActList; 53 54 /* Per-section structure. */ 55 typedef struct dasm_Section { 56 int *rbuf; /* Biased buffer pointer (negative section bias). */ 57 int *buf; /* True buffer pointer. */ 58 size_t bsize; /* Buffer size in bytes. */ 59 int pos; /* Biased buffer position. */ 60 int epos; /* End of biased buffer position - max single put. */ 61 int ofs; /* Byte offset into section. */ 62 } dasm_Section; 63 64 /* Core structure holding the DynASM encoding state. */ 65 struct dasm_State { 66 size_t psize; /* Allocated size of this structure. */ 67 dasm_ActList actionlist; /* Current actionlist pointer. */ 68 int *lglabels; /* Local/global chain/pos ptrs. */ 69 size_t lgsize; 70 int *pclabels; /* PC label chains/pos ptrs. */ 71 size_t pcsize; 72 void **globals; /* Array of globals (bias -10). */ 73 dasm_Section *section; /* Pointer to active section. */ 74 size_t codesize; /* Total size of all code sections. */ 75 int maxsection; /* 0 <= sectionidx < maxsection. */ 76 int status; /* Status code. */ 77 dasm_Section sections[1]; /* All sections. Alloc-extended. */ 78 }; 79 80 /* The size of the core structure depends on the max. number of sections. */ 81 #define DASM_PSZ(ms) (sizeof(dasm_State)+(ms-1)*sizeof(dasm_Section)) 82 83 84 /* Initialize DynASM state. */ 85 void dasm_init(Dst_DECL, int maxsection) 86 { 87 dasm_State *D; 88 size_t psz = 0; 89 int i; 90 Dst_REF = NULL; 91 DASM_M_GROW(Dst, struct dasm_State, Dst_REF, psz, DASM_PSZ(maxsection)); 92 D = Dst_REF; 93 D->psize = psz; 94 D->lglabels = NULL; 95 D->lgsize = 0; 96 D->pclabels = NULL; 97 D->pcsize = 0; 98 D->globals = NULL; 99 D->maxsection = maxsection; 100 for (i = 0; i < maxsection; i++) { 101 D->sections[i].buf = NULL; /* Need this for pass3. */ 102 D->sections[i].rbuf = D->sections[i].buf - DASM_SEC2POS(i); 103 D->sections[i].bsize = 0; 104 D->sections[i].epos = 0; /* Wrong, but is recalculated after resize. */ 105 } 106 } 107 108 /* Free DynASM state. */ 109 void dasm_free(Dst_DECL) 110 { 111 dasm_State *D = Dst_REF; 112 int i; 113 for (i = 0; i < D->maxsection; i++) 114 if (D->sections[i].buf) 115 DASM_M_FREE(Dst, D->sections[i].buf, D->sections[i].bsize); 116 if (D->pclabels) DASM_M_FREE(Dst, D->pclabels, D->pcsize); 117 if (D->lglabels) DASM_M_FREE(Dst, D->lglabels, D->lgsize); 118 DASM_M_FREE(Dst, D, D->psize); 119 } 120 121 /* Setup global label array. Must be called before dasm_setup(). */ 122 void dasm_setupglobal(Dst_DECL, void **gl, unsigned int maxgl) 123 { 124 dasm_State *D = Dst_REF; 125 D->globals = gl - 10; /* Negative bias to compensate for locals. */ 126 DASM_M_GROW(Dst, int, D->lglabels, D->lgsize, (10+maxgl)*sizeof(int)); 127 } 128 129 /* Grow PC label array. Can be called after dasm_setup(), too. */ 130 void dasm_growpc(Dst_DECL, unsigned int maxpc) 131 { 132 dasm_State *D = Dst_REF; 133 size_t osz = D->pcsize; 134 DASM_M_GROW(Dst, int, D->pclabels, D->pcsize, maxpc*sizeof(int)); 135 memset((void *)(((unsigned char *)D->pclabels)+osz), 0, D->pcsize-osz); 136 } 137 138 /* Setup encoder. */ 139 void dasm_setup(Dst_DECL, const void *actionlist) 140 { 141 dasm_State *D = Dst_REF; 142 int i; 143 D->actionlist = (dasm_ActList)actionlist; 144 D->status = DASM_S_OK; 145 D->section = &D->sections[0]; 146 memset((void *)D->lglabels, 0, D->lgsize); 147 if (D->pclabels) memset((void *)D->pclabels, 0, D->pcsize); 148 for (i = 0; i < D->maxsection; i++) { 149 D->sections[i].pos = DASM_SEC2POS(i); 150 D->sections[i].ofs = 0; 151 } 152 } 153 154 155 #ifdef DASM_CHECKS 156 #define CK(x, st) \ 157 do { if (!(x)) { \ 158 D->status = DASM_S_##st|(p-D->actionlist-1); return; } } while (0) 159 #define CKPL(kind, st) \ 160 do { if ((size_t)((char *)pl-(char *)D->kind##labels) >= D->kind##size) { \ 161 D->status = DASM_S_RANGE_##st|(p-D->actionlist-1); return; } } while (0) 162 #else 163 #define CK(x, st) ((void)0) 164 #define CKPL(kind, st) ((void)0) 165 #endif 166 167 /* Pass 1: Store actions and args, link branches/labels, estimate offsets. */ 168 void dasm_put(Dst_DECL, int start, ...) 169 { 170 va_list ap; 171 dasm_State *D = Dst_REF; 172 dasm_ActList p = D->actionlist + start; 173 dasm_Section *sec = D->section; 174 int pos = sec->pos, ofs = sec->ofs; 175 int *b; 176 177 if (pos >= sec->epos) { 178 DASM_M_GROW(Dst, int, sec->buf, sec->bsize, 179 sec->bsize + 2*DASM_MAXSECPOS*sizeof(int)); 180 sec->rbuf = sec->buf - DASM_POS2BIAS(pos); 181 sec->epos = (int)sec->bsize/sizeof(int) - DASM_MAXSECPOS+DASM_POS2BIAS(pos); 182 } 183 184 b = sec->rbuf; 185 b[pos++] = start; 186 187 va_start(ap, start); 188 while (1) { 189 unsigned int ins = *p++; 190 unsigned int action = (ins >> 16) - 0xff00; 191 if (action >= DASM__MAX) { 192 ofs += 4; 193 } else { 194 int *pl, n = action >= DASM_REL_PC ? va_arg(ap, int) : 0; 195 switch (action) { 196 case DASM_STOP: goto stop; 197 case DASM_SECTION: 198 n = (ins & 255); CK(n < D->maxsection, RANGE_SEC); 199 D->section = &D->sections[n]; goto stop; 200 case DASM_ESC: p++; ofs += 4; break; 201 case DASM_REL_EXT: break; 202 case DASM_ALIGN: ofs += (ins & 255); b[pos++] = ofs; break; 203 case DASM_REL_LG: 204 n = (ins & 2047) - 10; pl = D->lglabels + n; 205 /* Bkwd rel or global. */ 206 if (n >= 0) { CK(n>=10||*pl<0, RANGE_LG); CKPL(lg, LG); goto putrel; } 207 pl += 10; n = *pl; 208 if (n < 0) n = 0; /* Start new chain for fwd rel if label exists. */ 209 goto linkrel; 210 case DASM_REL_PC: 211 pl = D->pclabels + n; CKPL(pc, PC); 212 putrel: 213 n = *pl; 214 if (n < 0) { /* Label exists. Get label pos and store it. */ 215 b[pos] = -n; 216 } else { 217 linkrel: 218 b[pos] = n; /* Else link to rel chain, anchored at label. */ 219 *pl = pos; 220 } 221 pos++; 222 break; 223 case DASM_LABEL_LG: 224 pl = D->lglabels + (ins & 2047) - 10; CKPL(lg, LG); goto putlabel; 225 case DASM_LABEL_PC: 226 pl = D->pclabels + n; CKPL(pc, PC); 227 putlabel: 228 n = *pl; /* n > 0: Collapse rel chain and replace with label pos. */ 229 while (n > 0) { int *pb = DASM_POS2PTR(D, n); n = *pb; *pb = pos; 230 } 231 *pl = -pos; /* Label exists now. */ 232 b[pos++] = ofs; /* Store pass1 offset estimate. */ 233 break; 234 case DASM_IMM: case DASM_IMMS: 235 #ifdef DASM_CHECKS 236 CK((n & ((1<<((ins>>10)&31))-1)) == 0, RANGE_I); 237 #endif 238 n >>= ((ins>>10)&31); 239 #ifdef DASM_CHECKS 240 if (ins & 0x8000) 241 CK(((n + (1<<(((ins>>5)&31)-1)))>>((ins>>5)&31)) == 0, RANGE_I); 242 else 243 CK((n>>((ins>>5)&31)) == 0, RANGE_I); 244 #endif 245 b[pos++] = n; 246 break; 247 } 248 } 249 } 250 stop: 251 va_end(ap); 252 sec->pos = pos; 253 sec->ofs = ofs; 254 } 255 #undef CK 256 257 /* Pass 2: Link sections, shrink aligns, fix label offsets. */ 258 int dasm_link(Dst_DECL, size_t *szp) 259 { 260 dasm_State *D = Dst_REF; 261 int secnum; 262 int ofs = 0; 263 264 #ifdef DASM_CHECKS 265 *szp = 0; 266 if (D->status != DASM_S_OK) return D->status; 267 { 268 int pc; 269 for (pc = 0; pc*sizeof(int) < D->pcsize; pc++) 270 if (D->pclabels[pc] > 0) return DASM_S_UNDEF_PC|pc; 271 } 272 #endif 273 274 { /* Handle globals not defined in this translation unit. */ 275 int idx; 276 for (idx = 20; idx*sizeof(int) < D->lgsize; idx++) { 277 int n = D->lglabels[idx]; 278 /* Undefined label: Collapse rel chain and replace with marker (< 0). */ 279 while (n > 0) { int *pb = DASM_POS2PTR(D, n); n = *pb; *pb = -idx; } 280 } 281 } 282 283 /* Combine all code sections. No support for data sections (yet). */ 284 for (secnum = 0; secnum < D->maxsection; secnum++) { 285 dasm_Section *sec = D->sections + secnum; 286 int *b = sec->rbuf; 287 int pos = DASM_SEC2POS(secnum); 288 int lastpos = sec->pos; 289 290 while (pos != lastpos) { 291 dasm_ActList p = D->actionlist + b[pos++]; 292 while (1) { 293 unsigned int ins = *p++; 294 unsigned int action = (ins >> 16) - 0xff00; 295 switch (action) { 296 case DASM_STOP: case DASM_SECTION: goto stop; 297 case DASM_ESC: p++; break; 298 case DASM_REL_EXT: break; 299 case DASM_ALIGN: ofs -= (b[pos++] + ofs) & (ins & 255); break; 300 case DASM_REL_LG: case DASM_REL_PC: pos++; break; 301 case DASM_LABEL_LG: case DASM_LABEL_PC: b[pos++] += ofs; break; 302 case DASM_IMM: case DASM_IMMS: pos++; break; 303 } 304 } 305 stop: (void)0; 306 } 307 ofs += sec->ofs; /* Next section starts right after current section. */ 308 } 309 310 D->codesize = ofs; /* Total size of all code sections */ 311 *szp = ofs; 312 return DASM_S_OK; 313 } 314 315 #ifdef DASM_CHECKS 316 #define CK(x, st) \ 317 do { if (!(x)) return DASM_S_##st|(p-D->actionlist-1); } while (0) 318 #else 319 #define CK(x, st) ((void)0) 320 #endif 321 322 /* Pass 3: Encode sections. */ 323 int dasm_encode(Dst_DECL, void *buffer) 324 { 325 dasm_State *D = Dst_REF; 326 char *base = (char *)buffer; 327 unsigned int *cp = (unsigned int *)buffer; 328 int secnum; 329 330 /* Encode all code sections. No support for data sections (yet). */ 331 for (secnum = 0; secnum < D->maxsection; secnum++) { 332 dasm_Section *sec = D->sections + secnum; 333 int *b = sec->buf; 334 int *endb = sec->rbuf + sec->pos; 335 336 while (b != endb) { 337 dasm_ActList p = D->actionlist + *b++; 338 while (1) { 339 unsigned int ins = *p++; 340 unsigned int action = (ins >> 16) - 0xff00; 341 int n = (action >= DASM_ALIGN && action < DASM__MAX) ? *b++ : 0; 342 switch (action) { 343 case DASM_STOP: case DASM_SECTION: goto stop; 344 case DASM_ESC: *cp++ = *p++; break; 345 case DASM_REL_EXT: 346 n = DASM_EXTERN(Dst, (unsigned char *)cp, (ins & 2047), 1); 347 goto patchrel; 348 case DASM_ALIGN: 349 ins &= 255; while ((((char *)cp - base) & ins)) *cp++ = 0x60000000; 350 break; 351 case DASM_REL_LG: 352 CK(n >= 0, UNDEF_LG); 353 case DASM_REL_PC: 354 CK(n >= 0, UNDEF_PC); 355 n = *DASM_POS2PTR(D, n); 356 if (ins & 2048) 357 n = n - (int)((char *)cp - base); 358 else 359 n = (n + (int)(size_t)base) & 0x0fffffff; 360 patchrel: 361 CK((n & 3) == 0 && 362 ((n + ((ins & 2048) ? 0x00020000 : 0)) >> 363 ((ins & 2048) ? 18 : 28)) == 0, RANGE_REL); 364 cp[-1] |= ((n>>2) & ((ins & 2048) ? 0x0000ffff: 0x03ffffff)); 365 break; 366 case DASM_LABEL_LG: 367 ins &= 2047; if (ins >= 20) D->globals[ins-10] = (void *)(base + n); 368 break; 369 case DASM_LABEL_PC: break; 370 case DASM_IMMS: 371 cp[-1] |= ((n>>3) & 4); n &= 0x1f; 372 /* fallthrough */ 373 case DASM_IMM: 374 cp[-1] |= (n & ((1<<((ins>>5)&31))-1)) << (ins&31); 375 break; 376 default: *cp++ = ins; break; 377 } 378 } 379 stop: (void)0; 380 } 381 } 382 383 if (base + D->codesize != (char *)cp) /* Check for phase errors. */ 384 return DASM_S_PHASE; 385 return DASM_S_OK; 386 } 387 #undef CK 388 389 /* Get PC label offset. */ 390 int dasm_getpclabel(Dst_DECL, unsigned int pc) 391 { 392 dasm_State *D = Dst_REF; 393 if (pc*sizeof(int) < D->pcsize) { 394 int pos = D->pclabels[pc]; 395 if (pos < 0) return *DASM_POS2PTR(D, -pos); 396 if (pos > 0) return -1; /* Undefined. */ 397 } 398 return -2; /* Unused or out of range. */ 399 } 400 401 #ifdef DASM_CHECKS 402 /* Optional sanity checker to call between isolated encoding steps. */ 403 int dasm_checkstep(Dst_DECL, int secmatch) 404 { 405 dasm_State *D = Dst_REF; 406 if (D->status == DASM_S_OK) { 407 int i; 408 for (i = 1; i <= 9; i++) { 409 if (D->lglabels[i] > 0) { D->status = DASM_S_UNDEF_LG|i; break; } 410 D->lglabels[i] = 0; 411 } 412 } 413 if (D->status == DASM_S_OK && secmatch >= 0 && 414 D->section != &D->sections[secmatch]) 415 D->status = DASM_S_MATCH_SEC|(D->section-D->sections); 416 return D->status; 417 } 418 #endif 419