opcodes/bpf-dis.c

   1 /* DO NOT EDIT!  -*- buffer-read-only: t -*- vi:set ro:  */
   2 /* Disassembler interface for targets using CGEN. -*- C -*-
   3    CGEN: Cpu tools GENerator
   4
   5    THIS FILE IS MACHINE GENERATED WITH CGEN.
   6    - the resultant file is machine generated, cgen-dis.in isn't
   7
   8    Copyright (C) 1996-2019 Free Software Foundation, Inc.
   9
  10    This file is part of libopcodes.
  11
  12    This library is free software; you can redistribute it and/or modify
  13    it under the terms of the GNU General Public License as published by
  14    the Free Software Foundation; either version 3, or (at your option)
  15    any later version.
  16
  17    It is distributed in the hope that it will be useful, but WITHOUT
  18    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  19    or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
  20    License for more details.
  21
  22    You should have received a copy of the GNU General Public License
  23    along with this program; if not, write to the Free Software Foundation, Inc.,
  24    51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA.  */
  25
  26 /* ??? Eventually more and more of this stuff can go to cpu-independent files.
  27    Keep that in mind.  */
  28
  29 #include "sysdep.h"
  30 #include <stdio.h>
  31 #include "ansidecl.h"
  32 #include "disassemble.h"
  33 #include "bfd.h"
  34 #include "symcat.h"
  35 #include "libiberty.h"
  36 #include "bpf-desc.h"
  37 #include "bpf-opc.h"
  38 #include "opintl.h"
  39
  40 /* Default text to print if an instruction isn't recognized.  */
  41 #define UNKNOWN_INSN_MSG _("*unknown*")
  42
  43 static void print_normal
  44   (CGEN_CPU_DESC, void *, long, unsigned int, bfd_vma, int);
  45 static void print_address
  46   (CGEN_CPU_DESC, void *, bfd_vma, unsigned int, bfd_vma, int) ATTRIBUTE_UNUSED;
  47 static void print_keyword
  48   (CGEN_CPU_DESC, void *, CGEN_KEYWORD *, long, unsigned int) ATTRIBUTE_UNUSED;
  49 static void print_insn_normal
  50   (CGEN_CPU_DESC, void *, const CGEN_INSN *, CGEN_FIELDS *, bfd_vma, int);
  51 static int print_insn
  52   (CGEN_CPU_DESC, bfd_vma,  disassemble_info *, bfd_byte *, unsigned);
  53 static int default_print_insn
  54   (CGEN_CPU_DESC, bfd_vma, disassemble_info *) ATTRIBUTE_UNUSED;
  55 static int read_insn
  56   (CGEN_CPU_DESC, bfd_vma, disassemble_info *, bfd_byte *, int, CGEN_EXTRACT_INFO *,
  57    unsigned long *);
  58 \f
  59 /* -- disassembler routines inserted here.  */
  60
  61 /* -- dis.c */
  62
  63 /* We need to customize the disassembler a bit:
  64    - Use 8 bytes per line by default.
  65 */
  66
  67 #define CGEN_PRINT_INSN bpf_print_insn
  68
  69 static int
  70 bpf_print_insn (CGEN_CPU_DESC cd, bfd_vma pc, disassemble_info *info)
  71 {
  72   bfd_byte buf[CGEN_MAX_INSN_SIZE];
  73   int buflen;
  74   int status;
  75
  76   info->bytes_per_chunk = 1;
  77   info->bytes_per_line = 8;
  78
  79   /* Attempt to read the base part of the insn.  */
  80   buflen = cd->base_insn_bitsize / 8;
  81   status = (*info->read_memory_func) (pc, buf, buflen, info);
  82
  83   /* Try again with the minimum part, if min < base.  */
  84   if (status != 0 && (cd->min_insn_bitsize < cd->base_insn_bitsize))
  85     {
  86       buflen = cd->min_insn_bitsize / 8;
  87       status = (*info->read_memory_func) (pc, buf, buflen, info);
  88     }
  89
  90   if (status != 0)
  91     {
  92       (*info->memory_error_func) (status, pc, info);
  93       return -1;
  94     }
  95
  96   return print_insn (cd, pc, info, buf, buflen);
  97 }
  98
  99 /* Signed immediates should be printed in hexadecimal.  */
 100
 101 static void
 102 print_immediate (CGEN_CPU_DESC cd ATTRIBUTE_UNUSED,
 103                  void *dis_info,
 104                  int64_t value,
 105                  unsigned int attrs ATTRIBUTE_UNUSED,
 106                  bfd_vma pc ATTRIBUTE_UNUSED,
 107                  int length ATTRIBUTE_UNUSED)
 108 {
 109   disassemble_info *info = (disassemble_info *) dis_info;
 110
 111   if (value <= 9)
 112     (*info->fprintf_func) (info->stream, "%" PRId64, value);
 113   else
 114     (*info->fprintf_func) (info->stream, "%#" PRIx64, value);
 115
 116   /* This is to avoid -Wunused-function for print_normal.  */
 117   if (0)
 118     print_normal (cd, dis_info, value, attrs, pc, length);
 119 }
 120
 121 /* Endianness bit sizes should be printed in decimal.  */
 122
 123 static void
 124 print_endsize (CGEN_CPU_DESC cd ATTRIBUTE_UNUSED,
 125                void *dis_info,
 126                unsigned long value,
 127                unsigned int attrs ATTRIBUTE_UNUSED,
 128                bfd_vma pc ATTRIBUTE_UNUSED,
 129                int length ATTRIBUTE_UNUSED)
 130 {
 131   disassemble_info *info = (disassemble_info *) dis_info;
 132   (*info->fprintf_func) (info->stream, "%lu", value);
 133 }
 134
 135 \f
 136 /* -- */
 137
 138 void bpf_cgen_print_operand
 139   (CGEN_CPU_DESC, int, PTR, CGEN_FIELDS *, void const *, bfd_vma, int);
 140
 141 /* Main entry point for printing operands.
 142    XINFO is a `void *' and not a `disassemble_info *' to not put a requirement
 143    of dis-asm.h on cgen.h.
 144
 145    This function is basically just a big switch statement.  Earlier versions
 146    used tables to look up the function to use, but
 147    - if the table contains both assembler and disassembler functions then
 148      the disassembler contains much of the assembler and vice-versa,
 149    - there's a lot of inlining possibilities as things grow,
 150    - using a switch statement avoids the function call overhead.
 151
 152    This function could be moved into `print_insn_normal', but keeping it
 153    separate makes clear the interface between `print_insn_normal' and each of
 154    the handlers.  */
 155
 156 void
 157 bpf_cgen_print_operand (CGEN_CPU_DESC cd,
 158                            int opindex,
 159                            void * xinfo,
 160                            CGEN_FIELDS *fields,
 161                            void const *attrs ATTRIBUTE_UNUSED,
 162                            bfd_vma pc,
 163                            int length)
 164 {
 165   disassemble_info *info = (disassemble_info *) xinfo;
 166
 167   switch (opindex)
 168     {
 169     case BPF_OPERAND_DISP16 :
 170       print_normal (cd, info, fields->f_offset16, 0|(1<<CGEN_OPERAND_SIGNED)|(1<<CGEN_OPERAND_PCREL_ADDR), pc, length);
 171       break;
 172     case BPF_OPERAND_DISP32 :
 173       print_normal (cd, info, fields->f_imm32, 0|(1<<CGEN_OPERAND_SIGNED)|(1<<CGEN_OPERAND_PCREL_ADDR), pc, length);
 174       break;
 175     case BPF_OPERAND_DSTBE :
 176       print_keyword (cd, info, & bpf_cgen_opval_h_gpr, fields->f_dstbe, 0);
 177       break;
 178     case BPF_OPERAND_DSTLE :
 179       print_keyword (cd, info, & bpf_cgen_opval_h_gpr, fields->f_dstle, 0);
 180       break;
 181     case BPF_OPERAND_ENDSIZE :
 182       print_endsize (cd, info, fields->f_imm32, 0, pc, length);
 183       break;
 184     case BPF_OPERAND_IMM32 :
 185       print_immediate (cd, info, fields->f_imm32, 0|(1<<CGEN_OPERAND_SIGNED), pc, length);
 186       break;
 187     case BPF_OPERAND_IMM64 :
 188       print_immediate (cd, info, fields->f_imm64, 0|(1<<CGEN_OPERAND_SIGNED)|(1<<CGEN_OPERAND_VIRTUAL), pc, length);
 189       break;
 190     case BPF_OPERAND_OFFSET16 :
 191       print_immediate (cd, info, fields->f_offset16, 0|(1<<CGEN_OPERAND_SIGNED), pc, length);
 192       break;
 193     case BPF_OPERAND_SRCBE :
 194       print_keyword (cd, info, & bpf_cgen_opval_h_gpr, fields->f_srcbe, 0);
 195       break;
 196     case BPF_OPERAND_SRCLE :
 197       print_keyword (cd, info, & bpf_cgen_opval_h_gpr, fields->f_srcle, 0);
 198       break;
 199
 200     default :
 201       /* xgettext:c-format */
 202       opcodes_error_handler
 203         (_("internal error: unrecognized field %d while printing insn"),
 204          opindex);
 205       abort ();
 206   }
 207 }
 208
 209 cgen_print_fn * const bpf_cgen_print_handlers[] =
 210 {
 211   print_insn_normal,
 212 };
 213
 214
 215 void
 216 bpf_cgen_init_dis (CGEN_CPU_DESC cd)
 217 {
 218   bpf_cgen_init_opcode_table (cd);
 219   bpf_cgen_init_ibld_table (cd);
 220   cd->print_handlers = & bpf_cgen_print_handlers[0];
 221   cd->print_operand = bpf_cgen_print_operand;
 222 }
 223
 224 \f
 225 /* Default print handler.  */
 226
 227 static void
 228 print_normal (CGEN_CPU_DESC cd ATTRIBUTE_UNUSED,
 229               void *dis_info,
 230               long value,
 231               unsigned int attrs,
 232               bfd_vma pc ATTRIBUTE_UNUSED,
 233               int length ATTRIBUTE_UNUSED)
 234 {
 235   disassemble_info *info = (disassemble_info *) dis_info;
 236
 237   /* Print the operand as directed by the attributes.  */
 238   if (CGEN_BOOL_ATTR (attrs, CGEN_OPERAND_SEM_ONLY))
 239     ; /* nothing to do */
 240   else if (CGEN_BOOL_ATTR (attrs, CGEN_OPERAND_SIGNED))
 241     (*info->fprintf_func) (info->stream, "%ld", value);
 242   else
 243     (*info->fprintf_func) (info->stream, "0x%lx", value);
 244 }
 245
 246 /* Default address handler.  */
 247
 248 static void
 249 print_address (CGEN_CPU_DESC cd ATTRIBUTE_UNUSED,
 250                void *dis_info,
 251                bfd_vma value,
 252                unsigned int attrs,
 253                bfd_vma pc ATTRIBUTE_UNUSED,
 254                int length ATTRIBUTE_UNUSED)
 255 {
 256   disassemble_info *info = (disassemble_info *) dis_info;
 257
 258   /* Print the operand as directed by the attributes.  */
 259   if (CGEN_BOOL_ATTR (attrs, CGEN_OPERAND_SEM_ONLY))
 260     ; /* Nothing to do.  */
 261   else if (CGEN_BOOL_ATTR (attrs, CGEN_OPERAND_PCREL_ADDR))
 262     (*info->print_address_func) (value, info);
 263   else if (CGEN_BOOL_ATTR (attrs, CGEN_OPERAND_ABS_ADDR))
 264     (*info->print_address_func) (value, info);
 265   else if (CGEN_BOOL_ATTR (attrs, CGEN_OPERAND_SIGNED))
 266     (*info->fprintf_func) (info->stream, "%ld", (long) value);
 267   else
 268     (*info->fprintf_func) (info->stream, "0x%lx", (long) value);
 269 }
 270
 271 /* Keyword print handler.  */
 272
 273 static void
 274 print_keyword (CGEN_CPU_DESC cd ATTRIBUTE_UNUSED,
 275                void *dis_info,
 276                CGEN_KEYWORD *keyword_table,
 277                long value,
 278                unsigned int attrs ATTRIBUTE_UNUSED)
 279 {
 280   disassemble_info *info = (disassemble_info *) dis_info;
 281   const CGEN_KEYWORD_ENTRY *ke;
 282
 283   ke = cgen_keyword_lookup_value (keyword_table, value);
 284   if (ke != NULL)
 285     (*info->fprintf_func) (info->stream, "%s", ke->name);
 286   else
 287     (*info->fprintf_func) (info->stream, "???");
 288 }
 289 \f
 290 /* Default insn printer.
 291
 292    DIS_INFO is defined as `void *' so the disassembler needn't know anything
 293    about disassemble_info.  */
 294
 295 static void
 296 print_insn_normal (CGEN_CPU_DESC cd,
 297                    void *dis_info,
 298                    const CGEN_INSN *insn,
 299                    CGEN_FIELDS *fields,
 300                    bfd_vma pc,
 301                    int length)
 302 {
 303   const CGEN_SYNTAX *syntax = CGEN_INSN_SYNTAX (insn);
 304   disassemble_info *info = (disassemble_info *) dis_info;
 305   const CGEN_SYNTAX_CHAR_TYPE *syn;
 306
 307   CGEN_INIT_PRINT (cd);
 308
 309   for (syn = CGEN_SYNTAX_STRING (syntax); *syn; ++syn)
 310     {
 311       if (CGEN_SYNTAX_MNEMONIC_P (*syn))
 312         {
 313           (*info->fprintf_func) (info->stream, "%s", CGEN_INSN_MNEMONIC (insn));
 314           continue;
 315         }
 316       if (CGEN_SYNTAX_CHAR_P (*syn))
 317         {
 318           (*info->fprintf_func) (info->stream, "%c", CGEN_SYNTAX_CHAR (*syn));
 319           continue;
 320         }
 321
 322       /* We have an operand.  */
 323       bpf_cgen_print_operand (cd, CGEN_SYNTAX_FIELD (*syn), info,
 324                                  fields, CGEN_INSN_ATTRS (insn), pc, length);
 325     }
 326 }
 327 \f
 328 /* Subroutine of print_insn. Reads an insn into the given buffers and updates
 329    the extract info.
 330    Returns 0 if all is well, non-zero otherwise.  */
 331
 332 static int
 333 read_insn (CGEN_CPU_DESC cd ATTRIBUTE_UNUSED,
 334            bfd_vma pc,
 335            disassemble_info *info,
 336            bfd_byte *buf,
 337            int buflen,
 338            CGEN_EXTRACT_INFO *ex_info,
 339            unsigned long *insn_value)
 340 {
 341   int status = (*info->read_memory_func) (pc, buf, buflen, info);
 342
 343   if (status != 0)
 344     {
 345       (*info->memory_error_func) (status, pc, info);
 346       return -1;
 347     }
 348
 349   ex_info->dis_info = info;
 350   ex_info->valid = (1 << buflen) - 1;
 351   ex_info->insn_bytes = buf;
 352
 353   *insn_value = bfd_get_bits (buf, buflen * 8, info->endian == BFD_ENDIAN_BIG);
 354   return 0;
 355 }
 356
 357 /* Utility to print an insn.
 358    BUF is the base part of the insn, target byte order, BUFLEN bytes long.
 359    The result is the size of the insn in bytes or zero for an unknown insn
 360    or -1 if an error occurs fetching data (memory_error_func will have
 361    been called).  */
 362
 363 static int
 364 print_insn (CGEN_CPU_DESC cd,
 365             bfd_vma pc,
 366             disassemble_info *info,
 367             bfd_byte *buf,
 368             unsigned int buflen)
 369 {
 370   CGEN_INSN_INT insn_value;
 371   const CGEN_INSN_LIST *insn_list;
 372   CGEN_EXTRACT_INFO ex_info;
 373   int basesize;
 374
 375   /* Extract base part of instruction, just in case CGEN_DIS_* uses it. */
 376   basesize = cd->base_insn_bitsize < buflen * 8 ?
 377                                      cd->base_insn_bitsize : buflen * 8;
 378   insn_value = cgen_get_insn_value (cd, buf, basesize);
 379
 380
 381   /* Fill in ex_info fields like read_insn would.  Don't actually call
 382      read_insn, since the incoming buffer is already read (and possibly
 383      modified a la m32r).  */
 384   ex_info.valid = (1 << buflen) - 1;
 385   ex_info.dis_info = info;
 386   ex_info.insn_bytes = buf;
 387
 388   /* The instructions are stored in hash lists.
 389      Pick the first one and keep trying until we find the right one.  */
 390
 391   insn_list = CGEN_DIS_LOOKUP_INSN (cd, (char *) buf, insn_value);
 392   while (insn_list != NULL)
 393     {
 394       const CGEN_INSN *insn = insn_list->insn;
 395       CGEN_FIELDS fields;
 396       int length;
 397       unsigned long insn_value_cropped;
 398
 399 #ifdef CGEN_VALIDATE_INSN_SUPPORTED
 400       /* Not needed as insn shouldn't be in hash lists if not supported.  */
 401       /* Supported by this cpu?  */
 402       if (! bpf_cgen_insn_supported (cd, insn))
 403         {
 404           insn_list = CGEN_DIS_NEXT_INSN (insn_list);
 405           continue;
 406         }
 407 #endif
 408
 409       /* Basic bit mask must be correct.  */
 410       /* ??? May wish to allow target to defer this check until the extract
 411          handler.  */
 412
 413       /* Base size may exceed this instruction's size.  Extract the
 414          relevant part from the buffer. */
 415       if ((unsigned) (CGEN_INSN_BITSIZE (insn) / 8) < buflen &&
 416           (unsigned) (CGEN_INSN_BITSIZE (insn) / 8) <= sizeof (unsigned long))
 417         insn_value_cropped = bfd_get_bits (buf, CGEN_INSN_BITSIZE (insn),
 418                                            info->endian == BFD_ENDIAN_BIG);
 419       else
 420         insn_value_cropped = insn_value;
 421
 422       if ((insn_value_cropped & CGEN_INSN_BASE_MASK (insn))
 423           == CGEN_INSN_BASE_VALUE (insn))
 424         {
 425           /* Printing is handled in two passes.  The first pass parses the
 426              machine insn and extracts the fields.  The second pass prints
 427              them.  */
 428
 429           /* Make sure the entire insn is loaded into insn_value, if it
 430              can fit.  */
 431           if (((unsigned) CGEN_INSN_BITSIZE (insn) > cd->base_insn_bitsize) &&
 432               (unsigned) (CGEN_INSN_BITSIZE (insn) / 8) <= sizeof (unsigned long))
 433             {
 434               unsigned long full_insn_value;
 435               int rc = read_insn (cd, pc, info, buf,
 436                                   CGEN_INSN_BITSIZE (insn) / 8,
 437                                   & ex_info, & full_insn_value);
 438               if (rc != 0)
 439                 return rc;
 440               length = CGEN_EXTRACT_FN (cd, insn)
 441                 (cd, insn, &ex_info, full_insn_value, &fields, pc);
 442             }
 443           else
 444             length = CGEN_EXTRACT_FN (cd, insn)
 445               (cd, insn, &ex_info, insn_value_cropped, &fields, pc);
 446
 447           /* Length < 0 -> error.  */
 448           if (length < 0)
 449             return length;
 450           if (length > 0)
 451             {
 452               CGEN_PRINT_FN (cd, insn) (cd, info, insn, &fields, pc, length);
 453               /* Length is in bits, result is in bytes.  */
 454               return length / 8;
 455             }
 456         }
 457
 458       insn_list = CGEN_DIS_NEXT_INSN (insn_list);
 459     }
 460
 461   return 0;
 462 }
 463
 464 /* Default value for CGEN_PRINT_INSN.
 465    The result is the size of the insn in bytes or zero for an unknown insn
 466    or -1 if an error occured fetching bytes.  */
 467
 468 #ifndef CGEN_PRINT_INSN
 469 #define CGEN_PRINT_INSN default_print_insn
 470 #endif
 471
 472 static int
 473 default_print_insn (CGEN_CPU_DESC cd, bfd_vma pc, disassemble_info *info)
 474 {
 475   bfd_byte buf[CGEN_MAX_INSN_SIZE];
 476   int buflen;
 477   int status;
 478
 479   /* Attempt to read the base part of the insn.  */
 480   buflen = cd->base_insn_bitsize / 8;
 481   status = (*info->read_memory_func) (pc, buf, buflen, info);
 482
 483   /* Try again with the minimum part, if min < base.  */
 484   if (status != 0 && (cd->min_insn_bitsize < cd->base_insn_bitsize))
 485     {
 486       buflen = cd->min_insn_bitsize / 8;
 487       status = (*info->read_memory_func) (pc, buf, buflen, info);
 488     }
 489
 490   if (status != 0)
 491     {
 492       (*info->memory_error_func) (status, pc, info);
 493       return -1;
 494     }
 495
 496   return print_insn (cd, pc, info, buf, buflen);
 497 }
 498
 499 /* Main entry point.
 500    Print one instruction from PC on INFO->STREAM.
 501    Return the size of the instruction (in bytes).  */
 502
 503 typedef struct cpu_desc_list
 504 {
 505   struct cpu_desc_list *next;
 506   CGEN_BITSET *isa;
 507   int mach;
 508   int endian;
 509   CGEN_CPU_DESC cd;
 510 } cpu_desc_list;
 511
 512 int
 513 print_insn_bpf (bfd_vma pc, disassemble_info *info)
 514 {
 515   static cpu_desc_list *cd_list = 0;
 516   cpu_desc_list *cl = 0;
 517   static CGEN_CPU_DESC cd = 0;
 518   static CGEN_BITSET *prev_isa;
 519   static int prev_mach;
 520   static int prev_endian;
 521   int length;
 522   CGEN_BITSET *isa;
 523   int mach;
 524   int endian = (info->endian == BFD_ENDIAN_BIG
 525                 ? CGEN_ENDIAN_BIG
 526                 : CGEN_ENDIAN_LITTLE);
 527   enum bfd_architecture arch;
 528
 529   /* ??? gdb will set mach but leave the architecture as "unknown" */
 530 #ifndef CGEN_BFD_ARCH
 531 #define CGEN_BFD_ARCH bfd_arch_bpf
 532 #endif
 533   arch = info->arch;
 534   if (arch == bfd_arch_unknown)
 535     arch = CGEN_BFD_ARCH;
 536
 537   /* There's no standard way to compute the machine or isa number
 538      so we leave it to the target.  */
 539 #ifdef CGEN_COMPUTE_MACH
 540   mach = CGEN_COMPUTE_MACH (info);
 541 #else
 542   mach = info->mach;
 543 #endif
 544
 545 #ifdef CGEN_COMPUTE_ISA
 546   {
 547     static CGEN_BITSET *permanent_isa;
 548
 549     if (!permanent_isa)
 550       permanent_isa = cgen_bitset_create (MAX_ISAS);
 551     isa = permanent_isa;
 552     cgen_bitset_clear (isa);
 553     cgen_bitset_add (isa, CGEN_COMPUTE_ISA (info));
 554   }
 555 #else
 556   isa = info->insn_sets;
 557 #endif
 558
 559   /* If we've switched cpu's, try to find a handle we've used before */
 560   if (cd
 561       && (cgen_bitset_compare (isa, prev_isa) != 0
 562           || mach != prev_mach
 563           || endian != prev_endian))
 564     {
 565       cd = 0;
 566       for (cl = cd_list; cl; cl = cl->next)
 567         {
 568           if (cgen_bitset_compare (cl->isa, isa) == 0 &&
 569               cl->mach == mach &&
 570               cl->endian == endian)
 571             {
 572               cd = cl->cd;
 573               prev_isa = cd->isas;
 574               break;
 575             }
 576         }
 577     }
 578
 579   /* If we haven't initialized yet, initialize the opcode table.  */
 580   if (! cd)
 581     {
 582       const bfd_arch_info_type *arch_type = bfd_lookup_arch (arch, mach);
 583       const char *mach_name;
 584
 585       if (!arch_type)
 586         abort ();
 587       mach_name = arch_type->printable_name;
 588
 589       prev_isa = cgen_bitset_copy (isa);
 590       prev_mach = mach;
 591       prev_endian = endian;
 592       cd = bpf_cgen_cpu_open (CGEN_CPU_OPEN_ISAS, prev_isa,
 593                                  CGEN_CPU_OPEN_BFDMACH, mach_name,
 594                                  CGEN_CPU_OPEN_ENDIAN, prev_endian,
 595                                  CGEN_CPU_OPEN_END);
 596       if (!cd)
 597         abort ();
 598
 599       /* Save this away for future reference.  */
 600       cl = xmalloc (sizeof (struct cpu_desc_list));
 601       cl->cd = cd;
 602       cl->isa = prev_isa;
 603       cl->mach = mach;
 604       cl->endian = endian;
 605       cl->next = cd_list;
 606       cd_list = cl;
 607
 608       bpf_cgen_init_dis (cd);
 609     }
 610
 611   /* We try to have as much common code as possible.
 612      But at this point some targets need to take over.  */
 613   /* ??? Some targets may need a hook elsewhere.  Try to avoid this,
 614      but if not possible try to move this hook elsewhere rather than
 615      have two hooks.  */
 616   length = CGEN_PRINT_INSN (cd, pc, info);
 617   if (length > 0)
 618     return length;
 619   if (length < 0)
 620     return -1;
 621
 622   (*info->fprintf_func) (info->stream, UNKNOWN_INSN_MSG);
 623   return cd->default_insn_bitsize / 8;
 624 }