neatas.c

   1 /*
   2  * neatas - a small arm assembler
   3  *
   4  * Copyright (C) 2011 Ali Gholami Rudi
   5  *
   6  * This program is released under GNU GPL version 2.
   7  */
   8 #include <ctype.h>
   9 #include <fcntl.h>
  10 #include <stdio.h>
  11 #include <stdlib.h>
  12 #include <string.h>
  13 #include <unistd.h>
  14 #include <sys/types.h>
  15 #include <sys/stat.h>
  16 #include "out.h"
  17
  18 #define BUFSIZE         (1 << 14)
  19 #define TOKLEN          128
  20
  21 #define DELIMS          ",:{}[]#=-+ \t\n/!^"
  22 #define TOK2(a)         ((a)[0] << 16 | (a)[1] << 8)
  23 #define TOK3(a)         ((a)[0] << 16 | (a)[1] << 8 | (a)[2])
  24
  25 static char buf[BUFSIZE];
  26 static int cur;
  27
  28 static char cs[BUFSIZE];
  29 static int cslen;
  30
  31 static void gen(unsigned long i)
  32 {
  33         memcpy(cs + cslen, &i, 4);
  34         cslen += 4;
  35 }
  36
  37 static int tok_read(char *s)
  38 {
  39         while (1) {
  40                 while (isspace(buf[cur]))
  41                         cur++;
  42                 if (buf[cur] == '/' && buf[cur + 1] == '*') {
  43                         while (buf[cur] && (buf[cur] != '*' || buf[cur + 1] != '/'))
  44                                 cur++;
  45                         continue;
  46                 }
  47                 if (buf[cur] == ';' || buf[cur] == '@') {
  48                         while (buf[cur] && buf[cur] != '\n')
  49                                 cur++;
  50                         continue;
  51                 }
  52                 break;
  53         }
  54         if (!strchr(DELIMS, buf[cur])) {
  55                 while (!strchr(DELIMS, buf[cur]))
  56                         *s++ = buf[cur++];
  57                 *s = '\0';
  58                 return 0;
  59         }
  60         s[0] = buf[cur++];
  61         s[1] = '\0';
  62         return s[0] != 0;
  63 }
  64
  65 static char tok[TOKLEN];
  66 static char tokc[TOKLEN];
  67 static int tok_next;
  68
  69 /* next token in lower-case */
  70 static char *tok_get(void)
  71 {
  72         char *s = tokc;
  73         char *d = tok;
  74         if (!tok_next) {
  75                 tok_read(tokc);
  76                 while (*s)
  77                         *d++ = tolower(*s++);
  78                 *d = '\0';
  79         }
  80         tok_next = 0;
  81         return tok;
  82 }
  83
  84 /* next token in original case */
  85 static char *tok_case(void)
  86 {
  87         tok_get();
  88         return tokc;
  89 }
  90
  91 /* have a look at the next token */
  92 static char *tok_see(void)
  93 {
  94         if (!tok_next)
  95                 tok_get();
  96         tok_next = 1;
  97         return tok;
  98 }
  99
 100 static char *digs = "0123456789abcdef";
 101
 102 static long num(char *s, int bits)
 103 {
 104         int b = 10;
 105         int neg = 0;
 106         long n = 0;
 107         if (*s == '-' || *s == '+') {
 108                 neg = *s == '-';
 109                 s++;
 110         }
 111         if (s[0] == '0' && s[1] == 'x') {
 112                 b = 16;
 113                 s += 2;
 114         }
 115         while (*s) {
 116                 int d = strchr(digs, *s) - digs;
 117                 n *= b;
 118                 n += d;
 119                 s++;
 120         }
 121         if (neg)
 122                 n = -n;
 123         return bits < 32 ? n & ((1ul << bits) - 1) : n;
 124 }
 125
 126 #define NLOCALS         1024
 127 #define NEXTERNS        1024
 128 #define NAMELEN         32
 129
 130 static char locals[NLOCALS][NAMELEN];
 131 static char loffs[NLOCALS];
 132 static int nlocals;
 133 static char externs[NEXTERNS][NAMELEN];
 134 static int nexterns;
 135 static char globals[NEXTERNS][NAMELEN];
 136 static int nglobals;
 137
 138 static void label_extern(char *name)
 139 {
 140         int idx = nexterns++;
 141         strcpy(externs[idx], name);
 142 }
 143
 144 static void label_global(char *name)
 145 {
 146         int idx = nglobals++;
 147         strcpy(globals[idx], name);
 148 }
 149
 150 static void label_local(char *name)
 151 {
 152         int idx = nlocals++;
 153         strcpy(locals[idx], name);
 154         loffs[idx] = cslen;
 155         out_sym(locals[idx], OUT_CS, loffs[idx], 0);
 156 }
 157
 158 static int label_isextern(char *name)
 159 {
 160         int i;
 161         for (i = 0; i < nexterns; i++)
 162                 if (!strcmp(name, externs[i]))
 163                         return 1;
 164         return 0;
 165 }
 166
 167 static int label_offset(char *name)
 168 {
 169         int i;
 170         for (i = 0; i < nlocals; i++)
 171                 if (!strcmp(name, locals[i]))
 172                         return loffs[i];
 173         return 0;
 174 }
 175
 176 static void label_write(void)
 177 {
 178         int i;
 179         for (i = 0; i < nglobals; i++)
 180                 out_sym(globals[i], OUT_GLOB | OUT_CS,
 181                         label_offset(globals[i]), 0);
 182 }
 183
 184 #define NRELOCS         1024
 185
 186 /* absolute relocations */
 187 static char absns[NRELOCS][NAMELEN];    /* symbol name */
 188 static long absos[NRELOCS];             /* relocation location */
 189 static int nabs;
 190 /* relative relocations */
 191 static char relns[NRELOCS][NAMELEN];    /* symbol name */
 192 static long relos[NRELOCS];             /* relocation location */
 193 static long relas[NRELOCS];             /* relocation addend */
 194 static long relbs[NRELOCS];             /* relocation bits: ldrh=8, 12=ldr, 24=bl */
 195 static int nrel;
 196
 197 static void reloc_rel(char *name, long off, int bits)
 198 {
 199         int idx = nrel++;
 200         strcpy(relns[idx], name);
 201         relos[idx] = cslen;
 202         relas[idx] = off;
 203         relbs[idx] = bits;
 204 }
 205
 206 static void reloc_abs(char *name)
 207 {
 208         int idx = nabs++;
 209         strcpy(absns[idx], name);
 210         absos[idx] = cslen;
 211 }
 212
 213 #define CSBEG_NAME              "__neatas_cs"
 214
 215 /* fill immediate value for bl instruction */
 216 static void bl_imm(long *dst, long imm)
 217 {
 218         imm = ((*dst << 2) + imm) >> 2;
 219         *dst = (*dst & 0xff000000) | (imm & 0x00ffffff);
 220 }
 221
 222 /* fill immediate value for ldr instruction */
 223 static void ldr_imm(long *dst, long imm, int half)
 224 {
 225         /* set u-bit for negative offsets */
 226         if (imm < 0) {
 227                 *dst ^= (1 << 23);
 228                 imm = -imm;
 229         }
 230         if (!half)
 231                 *dst = (*dst & 0xfffff000) | ((*dst + imm) & 0x00000fff);
 232         if (half)
 233                 *dst = (*dst & 0xfffff0f0) |
 234                                 (imm & 0x0f) | ((imm & 0xf0) << 4);
 235 }
 236
 237 static void reloc_write(void)
 238 {
 239         int i;
 240         out_sym(CSBEG_NAME, OUT_CS, 0, 0);
 241         for (i = 0; i < nabs; i++) {
 242                 if (label_isextern(absns[i])) {
 243                         out_rel(absns[i], OUT_CS, absos[i]);
 244                 } else {
 245                         long off = label_offset(absns[i]);
 246                         out_rel(CSBEG_NAME, OUT_CS, absos[i]);
 247                         *(long *) (cs + absos[i]) += off;
 248                 }
 249         }
 250         for (i = 0; i < nrel; i++) {
 251                 long *dst = (void *) cs + relos[i];
 252                 long off;
 253                 if (label_isextern(relns[i])) {
 254                         out_rel(relns[i], OUT_CS | OUT_REL24, relos[i]);
 255                         bl_imm(dst, relas[i] - 8);
 256                         continue;
 257                 }
 258                 off = relas[i] + label_offset(relns[i]) - relos[i] - 8;
 259                 /* bl instruction */
 260                 if (relbs[i] == 24)
 261                         bl_imm(dst, off);
 262                 else
 263                         ldr_imm(dst, off, relbs[i] == 8);
 264         }
 265 }
 266
 267 #define NDATS           1024
 268
 269 /* data pool */
 270 static long dat_offs[NDATS];            /* data immediate value */
 271 static long dat_locs[NDATS];            /* address of pointing ldr */
 272 static char dat_names[NDATS][NAMELEN];  /* relocation data symbol name */
 273 static int ndats;
 274
 275 static void pool_num(long num)
 276 {
 277         int idx = ndats++;
 278         dat_offs[idx] = num;
 279         dat_locs[idx] = cslen;
 280 }
 281
 282 static void pool_reloc(char *name, long off)
 283 {
 284         int idx = ndats++;
 285         dat_offs[idx] = off;
 286         dat_locs[idx] = cslen;
 287         strcpy(dat_names[idx], name);
 288 }
 289
 290 static void pool_write(void)
 291 {
 292         int i;
 293         for (i = 0; i < ndats; i++) {
 294                 if (dat_names[i]) {
 295                         long *loc = (void *) cs + dat_locs[i];
 296                         int off = cslen - dat_locs[i] - 8;
 297                         reloc_abs(dat_names[i]);
 298                         /* ldrh needs special care */
 299                         if (*loc & (1 << 26))
 300                                 *loc = (*loc & 0xfffff000) | (off & 0x00000fff);
 301                         else
 302                                 *loc = (*loc & 0xfffff0f0) | (off & 0x0f) |
 303                                         ((off & 0xf0) << 4);
 304                 }
 305                 gen(dat_offs[i]);
 306         }
 307 }
 308
 309 static char *dpops[] = {
 310         "and", "eor", "sub", "rsb", "add", "adc", "sbc", "rsc",
 311         "tst", "teq", "cmp", "cmn", "orr", "mov", "bic", "mvn"
 312 };
 313
 314 static char *conds[] = {
 315         "eq", "ne", "cs", "cc", "mi", "pl", "vs", "vc",
 316         "hi", "ls", "ge", "lt", "gt", "le", "al", "nv"
 317 };
 318
 319 static char *regs[] = {
 320         "a1", "a2", "a3", "a4", "v1", "v2", "v3", "v4",
 321         "v5", "v6", "v7", "v8", "ip", "sp", "lr", "pc"
 322 };
 323
 324 static int get_reg(char *s)
 325 {
 326         int i;
 327         if (s[0] == 'f' && s[1] == 'p')
 328                 return 11;
 329         for (i = 0; i < 16; i++)
 330                 if (TOK2(s) == TOK2(regs[i]))
 331                         return i;
 332         if (s[0] == 'r')
 333                 return atoi(s + 1);
 334         return -1;
 335 }
 336
 337 static void fill_buf(int fd)
 338 {
 339         int len = 0;
 340         int nr;
 341         while ((nr = read(fd, buf + len, sizeof(buf) - len - 1)) > 0)
 342                 len += nr;
 343         buf[len] = '\0';
 344 }
 345
 346 static int tok_jmp(char *s)
 347 {
 348         if (!strcmp(s, tok_see())) {
 349                 tok_get();
 350                 return 0;
 351         }
 352         return 1;
 353 }
 354
 355 static void tok_expect(char *s)
 356 {
 357         if (strcmp(s, tok_get())) {
 358                 fprintf(stderr, "syntax error\n");
 359                 exit(1);
 360         }
 361 }
 362
 363 static int get_cond(char *s)
 364 {
 365         int i;
 366         if (s[0] == 'h' && s[1] == 's')
 367                 return 2;
 368         if (s[0] == 'l' && s[1] == 'o')
 369                 return 3;
 370         for (i = 0; i < 16; i++)
 371                 if (TOK2(s) == TOK2(conds[i]))
 372                         return i;
 373         return -1;
 374 }
 375
 376 static int add_op(char *s)
 377 {
 378         int i;
 379         for (i = 0; i < 16; i++)
 380                 if (TOK3(s) == TOK3(dpops[i]))
 381                         return i;
 382         return -1;
 383 }
 384
 385 static int shiftmode(char *s)
 386 {
 387         if (TOK3(s) == TOK3("lsl"))
 388                 return 0;
 389         if (TOK3(s) == TOK3("lsr"))
 390                 return 1;
 391         if (TOK3(s) == TOK3("asr"))
 392                 return 2;
 393         if (TOK3(s) == TOK3("ror"))
 394                 return 3;
 395         return 0;
 396 }
 397
 398 static int ldr_word(void)
 399 {
 400         int sm = 0;
 401         int rm;
 402         int shifts = 0;
 403         int u = 1;
 404         if (tok_jmp(","))
 405                 return 0;
 406         if (!tok_jmp("#")) {
 407                 u = tok_jmp("-");
 408                 return (u << 23) | num(tok_get(), 12);
 409         }
 410         if (!tok_jmp("-"))
 411                 u = 0;
 412         rm = get_reg(tok_get());
 413         if (!tok_jmp(",")) {
 414                 sm = shiftmode(tok_get());
 415                 tok_expect("#");
 416                 shifts = num(tok_get(), 8);
 417         }
 418         return (1 << 25) | (u << 23) | (shifts << 7) | (sm << 5) | rm;
 419 }
 420
 421 static int ldr_half(int s, int h)
 422 {
 423         int u, n;
 424         int o = 0x90 | (s << 6) | (h << 5);
 425         if (tok_jmp(","))
 426                 return o | (1 << 22);
 427         if (!tok_jmp("#")) {
 428                 u = tok_jmp("-");
 429                 n = num(tok_get(), 8);
 430                 return o | (1 << 22) | (u << 23) | (n & 0x0f) | ((n & 0xf0) << 4);
 431         }
 432         u = tok_jmp("-");
 433         return o | (u << 23) | get_reg(tok_get());
 434 }
 435
 436 static long ldr_off(void)
 437 {
 438         long off = 0;
 439         while (1) {
 440                 if (!tok_jmp("-")) {
 441                         off -= num(tok_get(), 32);
 442                         continue;
 443                 }
 444                 if (!tok_jmp("+")) {
 445                         off += num(tok_get(), 32);
 446                         continue;
 447                 }
 448                 break;
 449         }
 450         return off;
 451 }
 452
 453 /*
 454  * single data transfer:
 455  * +------------------------------------------+
 456  * |COND|01|I|P|U|B|W|L| Rn | Rd |   offset   |
 457  * +------------------------------------------+
 458  *
 459  * I: immediate/offset
 460  * P: post/pre indexing
 461  * U: down/up
 462  * B: byte/word
 463  * W: writeback
 464  * L: store/load
 465  * Rn: base register
 466  * Rd: source/destination register
 467  *
 468  * I=1 offset=| immediate |
 469  * I=0 offset=| shift  | Rm |
 470  *
 471  * halfword and signed data transfer
 472  * +----------------------------------------------+
 473  * |COND|000|P|U|0|W|L| Rn | Rd |0000|1|S|H|1| Rm |
 474  * +----------------------------------------------+
 475  *
 476  * +----------------------------------------------+
 477  * |COND|000|P|U|1|W|L| Rn | Rd |off1|1|S|H|1|off2|
 478  * +----------------------------------------------+
 479  *
 480  * S: singed
 481  * H: halfword
 482  */
 483 static int ldr(char *cmd)
 484 {
 485         int l = 0;
 486         int rd, rn;
 487         int cond;
 488         int w = 0;
 489         int sign = 0;
 490         int byte = 0;
 491         int half = 0;
 492         int o;
 493         if (TOK3(cmd) != TOK3("ldr") && TOK3(cmd) != TOK3("str"))
 494                 return 1;
 495         if (TOK3(cmd) == TOK3("ldr"))
 496                 l = 1;
 497         cond = get_cond(cmd + 3);
 498         cmd += cond < 0 ? 2 : 5;
 499         if (cond < 0)
 500                 cond = 14;
 501         while (*++cmd) {
 502                 if (*cmd == 't')
 503                         w = 1;
 504                 if (*cmd == 'b')
 505                         byte = 1;
 506                 if (*cmd == 'h')
 507                         half = 1;
 508                 if (*cmd == 's')
 509                         sign = 1;
 510         }
 511         rd = get_reg(tok_get());
 512         tok_expect(",");
 513         o = (cond << 28) | (l << 20) | (rd << 12) | (half << 5) | (sign << 6);
 514         if (half || sign)
 515                 o |= 0x90;
 516         else
 517                 o |= (1 << 26);
 518         if (tok_jmp("[")) {
 519                 char sym[NAMELEN];
 520                 rn = 15;
 521                 if (!tok_jmp("=")) {
 522                         strcpy(sym, tok_case());
 523                         pool_reloc(sym, ldr_off());
 524                 } else {
 525                         strcpy(sym, tok_case());
 526                         reloc_rel(sym, ldr_off(), (half || sign) ? 8 : 12);
 527                 }
 528                 if (half || sign)
 529                         o |= (1 << 22);
 530                 else
 531                         o |= (1 << 26);
 532                 gen(o | (1 << 23) | (1 << 24) | (rn << 16));
 533                 return 0;
 534         }
 535         rn = get_reg(tok_get());
 536         o |= (rn << 16);
 537         if (!tok_jmp("]")) {
 538                 gen(o | (w << 21) | ((half || sign) ? ldr_half(sign, half) :
 539                                                 ldr_word()));
 540                 return 0;
 541         }
 542         o |= (1 << 24) | ((half || sign) ? ldr_half(sign, half) : ldr_word());
 543         tok_expect("]");
 544         if (!tok_jmp("!"))
 545                 o |= (1 << 21);
 546         gen(o);
 547         return 0;
 548 }
 549
 550 static int ldm_regs(void)
 551 {
 552         int o = 0;
 553         tok_expect("{");
 554         while (1) {
 555                 int r1 = get_reg(tok_get());
 556                 int r2 = r1;
 557                 int i;
 558                 if (!tok_jmp("-"))
 559                         r2 = get_reg(tok_get());
 560                 for (i = r1; i <= r2; i++)
 561                         o |= (1 << i);
 562                 if (tok_jmp(","))
 563                         break;
 564         }
 565         tok_expect("}");
 566         return o;
 567 }
 568
 569 static int ldm_type(char *s, int l)
 570 {
 571         int p = 0;
 572         int u = 0;
 573         if (*s == 'i' || *s == 'd') {
 574                 p = s[0] == 'i';
 575                 u = s[1] == 'b';
 576         } else {
 577                 p = s[0] == (l ? 'e' : 'f');
 578                 u = s[1] == (l ? 'd' : 'a');
 579         }
 580         return (p << 24) | (u << 23);
 581 }
 582
 583 /*
 584  * block data transfer
 585  * +----------------------------------------+
 586  * |COND|100|P|U|S|W|L| Rn |    reg list    |
 587  * +----------------------------------------+
 588  *
 589  * P: post/pre indexing
 590  * U: down/up
 591  * S: PSR/user bit
 592  * W: write back
 593  * L: load/store
 594  * Rn: base register
 595  */
 596 static int ldm(char *cmd)
 597 {
 598         int rn;
 599         int cond;
 600         int l = 0, w = 0, s = 0;
 601         int o = 4 << 25;
 602         if (TOK3(cmd) != TOK3("ldm") && TOK3(cmd) != TOK3("stm"))
 603                 return 1;
 604         if (TOK3(cmd) == TOK3("ldm"))
 605                 l = 1;
 606         cond = get_cond(cmd + 3);
 607         o |= ldm_type(cond < 0 ? cmd + 3 : cmd + 5, l);
 608         rn = get_reg(tok_get());
 609         if (!tok_jmp("!"))
 610                 w = 1;
 611         tok_expect(",");
 612         if (cond < 0)
 613                 cond = 14;
 614         o |= ldm_regs();
 615         if (!tok_jmp("^"))
 616                 s = 1;
 617         gen(o | (cond << 28) | (s << 22) | (w << 21) | (l << 20) | (rn << 16));
 618         return 0;
 619 }
 620
 621 static int add_encimm(unsigned n)
 622 {
 623         int i = 0;
 624         while (i < 12 && (n >> ((4 + i) << 1)))
 625                 i++;
 626         return (n >> (i << 1)) | (((16 - i) & 0x0f) << 8);
 627 }
 628
 629 static int add_op2(void)
 630 {
 631         int sm, rm;
 632         if (!tok_jmp("#"))
 633                 return (1 << 25) | add_encimm(num(tok_get(), 32));
 634         rm = get_reg(tok_get());
 635         if (tok_jmp(","))
 636                 return rm;
 637         sm = shiftmode(tok_get());
 638         if (!tok_jmp("#"))
 639                 return (num(tok_get(), 4) << 7) | (sm << 5) | (rm << 0);
 640         return (get_reg(tok_get()) << 8) | (sm << 5) | (1 << 4) | (rm << 0);
 641 }
 642
 643 /*
 644  * data processing:
 645  * +---------------------------------------+
 646  * |COND|00|I| op |S| Rn | Rd |  operand2  |
 647  * +---------------------------------------+
 648  *
 649  * S: set condition code
 650  * Rn: first operand
 651  * Rd: destination operand
 652  *
 653  * I=0 operand2=| shift  | Rm |
 654  * I=1 operand2=|rota|  imm   |
 655  */
 656 static int add(char *cmd)
 657 {
 658         int op, cond;
 659         int rd = 0, rn = 0;
 660         int nops = 2;
 661         int s = 0;
 662         op = add_op(cmd);
 663         if (op < 0)
 664                 return 1;
 665         cond = get_cond(cmd + 3);
 666         s = cmd[cond < 0 ? 3 : 6] == 's';
 667         if (op == 13 || op == 15)
 668                 nops = 1;
 669         if ((op & 0x0c) == 0x08)
 670                 s = 1;
 671         if (cond < 0)
 672                 cond = 14;
 673         if ((op & 0xc) != 0x8) {
 674                 rd = get_reg(tok_get());
 675                 tok_expect(",");
 676         }
 677         if (nops > 1) {
 678                 rn = get_reg(tok_get());
 679                 tok_expect(",");
 680         }
 681         gen((cond << 28) | (s << 20) | (op << 21) | (rn << 16) | (rd << 12) | add_op2());
 682         return 0;
 683 }
 684
 685 /*
 686  * multiply
 687  * +----------------------------------------+
 688  * |COND|000000|A|S| Rd | Rn | Rs |1001| Rm |
 689  * +----------------------------------------+
 690  *
 691  * Rd: destination
 692  * A: accumulate
 693  * C: set condition codes
 694  *
 695  * I=0 operand2=| shift  | Rm |
 696  * I=1 operand2=|rota|  imm   |
 697  */
 698 static int mul(char *cmd)
 699 {
 700         int cond;
 701         int rd, rm, rs, rn = 0;
 702         int s = 0;
 703         int a = 0;
 704         if (TOK3(cmd) != TOK3("mul") && TOK3(cmd) != TOK3("mla"))
 705                 return 1;
 706         if (TOK3(cmd) == TOK3("mla"))
 707                 a = 1;
 708         cond = get_cond(cmd + 3);
 709         s = cmd[cond < 0 ? 3 : 6] == 's';
 710         if (cond < 0)
 711                 cond = 14;
 712         rd = get_reg(tok_get());
 713         tok_expect(",");
 714         rm = get_reg(tok_get());
 715         tok_expect(",");
 716         rs = get_reg(tok_get());
 717         if (a) {
 718                 tok_expect(",");
 719                 rn = get_reg(tok_get());
 720         }
 721         gen((cond << 28) | (a << 21) | (s << 20) | (rd << 16) |
 722                 (rn << 12) | (rs << 8) | (9 << 4) | (rm << 0));
 723         return 0;
 724 }
 725
 726 /*
 727  * software interrupt:
 728  * +----------------------------------+
 729  * |COND|1111|                        |
 730  * +----------------------------------+
 731  *
 732  */
 733 static int swi(char *cmd)
 734 {
 735         int n;
 736         int cond;
 737         if (TOK3(cmd) != TOK3("swi"))
 738                 return 1;
 739         cond = get_cond(cmd + 3);
 740         if (cond == -1)
 741                 cond = 14;
 742         tok_jmp("#");
 743         n = num(tok_get(), 24);
 744         gen((cond << 28) | (0xf << 24) | n);
 745         return 0;
 746 }
 747
 748 /*
 749  * branch:
 750  * +-----------------------------------+
 751  * |COND|101|L|         offset         |
 752  * +-----------------------------------+
 753  *
 754  * L: link
 755  */
 756 static int bl(char *cmd)
 757 {
 758         int l = 0;
 759         int cond;
 760         char sym[NAMELEN];
 761         if (*cmd++ != 'b')
 762                 return 1;
 763         if (*cmd == 'l') {
 764                 l = 1;
 765                 cmd++;
 766         }
 767         cond = get_cond(cmd);
 768         if (cond == -1)
 769                 cond = 14;
 770         strcpy(sym, tok_case());
 771         reloc_rel(sym, ldr_off(), 24);
 772         gen((cond << 28) | (5 << 25) | (l << 24));
 773         return 0;
 774 }
 775
 776 /*
 777  * move PSR to a register
 778  * +-------------------------------------+
 779  * |COND|00010|P|001111| Rd |000000000000|
 780  * +-------------------------------------+
 781  *
 782  * move a register to PSR
 783  * +--------------------------------------+
 784  * |COND|00|I|10|P|1010001111| source op  |
 785  * +--------------------------------------+
 786  *
 787  * P: CPSR/SPSR_cur
 788  *
 789  * I=0 source=|00000000| Rm |
 790  * I=1 source=|rot | imm_u8 |
 791  */
 792 static int msr(char *cmd)
 793 {
 794         return 1;
 795 }
 796
 797 static int directive(char *cmd)
 798 {
 799         if (cmd[0] != '.')
 800                 return 1;
 801         if (!strcmp(".extern", cmd)) {
 802                 label_extern(tok_case());
 803         }
 804         if (!strcmp(".global", cmd)) {
 805                 label_global(tok_case());
 806         }
 807         if (!strcmp(".word", cmd)) {
 808                 do {
 809                         if (!tok_jmp("=")) {
 810                                 reloc_abs(tok_case());
 811                                 gen(ldr_off());
 812                         } else {
 813                                 gen(num(tok_get(), 32));
 814                         }
 815                 } while (!tok_jmp(","));
 816         }
 817         return 0;
 818 }
 819
 820 static int stmt(void)
 821 {
 822         char first[TOKLEN];
 823         char first_case[TOKLEN];
 824         strcpy(first, tok_see());
 825         strcpy(first_case, tok_case());
 826         /* a label */
 827         if (!tok_jmp(":")) {
 828                 label_local(first_case);
 829                 return 0;
 830         }
 831         if (!directive(first))
 832                 return 0;
 833         if (!add(first))
 834                 return 0;
 835         if (!mul(first))
 836                 return 0;
 837         if (!ldr(first))
 838                 return 0;
 839         if (!ldm(first))
 840                 return 0;
 841         if (!msr(first))
 842                 return 0;
 843         if (!swi(first))
 844                 return 0;
 845         if (!bl(first))
 846                 return 0;
 847         return 1;
 848 }
 849
 850 int main(int argc, char *argv[])
 851 {
 852         char obj[128] = "";
 853         char *src;
 854         int ofd, ifd;
 855         int i = 1;
 856         while (i < argc && argv[i][0] == '-') {
 857                 if (argv[i][1] == 'o')
 858                         strcpy(obj, argv[++i]);
 859                 i++;
 860         }
 861         if (i == argc) {
 862                 fprintf(stderr, "neatcc: no file given\n");
 863                 return 1;
 864         }
 865         src = argv[i];
 866         ifd = open(src, O_RDONLY);
 867         fill_buf(ifd);
 868         close(ifd);
 869         out_init(0);
 870         while (!stmt())
 871                 ;
 872         label_write();
 873         pool_write();
 874         reloc_write();
 875         if (!*obj) {
 876                 char *s = obj;
 877                 strcpy(obj, src);
 878                 while (*s && *s != '.')
 879                         s++;
 880                 *s++ = '.';
 881                 *s++ = 'o';
 882                 *s++ = '\0';
 883         }
 884         ofd = open(obj, O_WRONLY | O_TRUNC | O_CREAT, 0600);
 885         out_write(ofd, cs, cslen, cs, 0);
 886         close(ofd);
 887         return 0;
 888 }