opcodes/xstormy16-dis.c

   1 /* Disassembler interface for targets using CGEN. -*- C -*-
   2    CGEN: Cpu tools GENerator
   3
   4    THIS FILE IS MACHINE GENERATED WITH CGEN.
   5    - the resultant file is machine generated, cgen-dis.in isn't
   6
   7    Copyright 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2005
   8    Free Software Foundation, Inc.
   9
  10    This file is part of the GNU Binutils and GDB, the GNU debugger.
  11
  12    This program 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 2, or (at your option)
  15    any later version.
  16
  17    This program is distributed in the hope that it will be useful,
  18    but WITHOUT ANY WARRANTY; without even the implied warranty of
  19    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20    GNU General Public 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 "dis-asm.h"
  33 #include "bfd.h"
  34 #include "symcat.h"
  35 #include "libiberty.h"
  36 #include "xstormy16-desc.h"
  37 #include "xstormy16-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
  62 void xstormy16_cgen_print_operand
  63   (CGEN_CPU_DESC, int, PTR, CGEN_FIELDS *, void const *, bfd_vma, int);
  64
  65 /* Main entry point for printing operands.
  66    XINFO is a `void *' and not a `disassemble_info *' to not put a requirement
  67    of dis-asm.h on cgen.h.
  68
  69    This function is basically just a big switch statement.  Earlier versions
  70    used tables to look up the function to use, but
  71    - if the table contains both assembler and disassembler functions then
  72      the disassembler contains much of the assembler and vice-versa,
  73    - there's a lot of inlining possibilities as things grow,
  74    - using a switch statement avoids the function call overhead.
  75
  76    This function could be moved into `print_insn_normal', but keeping it
  77    separate makes clear the interface between `print_insn_normal' and each of
  78    the handlers.  */
  79
  80 void
  81 xstormy16_cgen_print_operand (CGEN_CPU_DESC cd,
  82                            int opindex,
  83                            void * xinfo,
  84                            CGEN_FIELDS *fields,
  85                            void const *attrs ATTRIBUTE_UNUSED,
  86                            bfd_vma pc,
  87                            int length)
  88 {
  89   disassemble_info *info = (disassemble_info *) xinfo;
  90
  91   switch (opindex)
  92     {
  93     case XSTORMY16_OPERAND_RB :
  94       print_keyword (cd, info, & xstormy16_cgen_opval_gr_Rb_names, fields->f_Rb, 0);
  95       break;
  96     case XSTORMY16_OPERAND_RBJ :
  97       print_keyword (cd, info, & xstormy16_cgen_opval_gr_Rb_names, fields->f_Rbj, 0);
  98       break;
  99     case XSTORMY16_OPERAND_RD :
 100       print_keyword (cd, info, & xstormy16_cgen_opval_gr_names, fields->f_Rd, 0);
 101       break;
 102     case XSTORMY16_OPERAND_RDM :
 103       print_keyword (cd, info, & xstormy16_cgen_opval_gr_names, fields->f_Rdm, 0);
 104       break;
 105     case XSTORMY16_OPERAND_RM :
 106       print_keyword (cd, info, & xstormy16_cgen_opval_gr_names, fields->f_Rm, 0);
 107       break;
 108     case XSTORMY16_OPERAND_RS :
 109       print_keyword (cd, info, & xstormy16_cgen_opval_gr_names, fields->f_Rs, 0);
 110       break;
 111     case XSTORMY16_OPERAND_ABS24 :
 112       print_normal (cd, info, fields->f_abs24, 0|(1<<CGEN_OPERAND_ABS_ADDR)|(1<<CGEN_OPERAND_VIRTUAL), pc, length);
 113       break;
 114     case XSTORMY16_OPERAND_BCOND2 :
 115       print_keyword (cd, info, & xstormy16_cgen_opval_h_branchcond, fields->f_op2, 0);
 116       break;
 117     case XSTORMY16_OPERAND_BCOND5 :
 118       print_keyword (cd, info, & xstormy16_cgen_opval_h_branchcond, fields->f_op5, 0);
 119       break;
 120     case XSTORMY16_OPERAND_HMEM8 :
 121       print_normal (cd, info, fields->f_hmem8, 0|(1<<CGEN_OPERAND_ABS_ADDR), pc, length);
 122       break;
 123     case XSTORMY16_OPERAND_IMM12 :
 124       print_normal (cd, info, fields->f_imm12, 0|(1<<CGEN_OPERAND_SIGNED), pc, length);
 125       break;
 126     case XSTORMY16_OPERAND_IMM16 :
 127       print_normal (cd, info, fields->f_imm16, 0|(1<<CGEN_OPERAND_SIGN_OPT), pc, length);
 128       break;
 129     case XSTORMY16_OPERAND_IMM2 :
 130       print_normal (cd, info, fields->f_imm2, 0, pc, length);
 131       break;
 132     case XSTORMY16_OPERAND_IMM3 :
 133       print_normal (cd, info, fields->f_imm3, 0, pc, length);
 134       break;
 135     case XSTORMY16_OPERAND_IMM3B :
 136       print_normal (cd, info, fields->f_imm3b, 0, pc, length);
 137       break;
 138     case XSTORMY16_OPERAND_IMM4 :
 139       print_normal (cd, info, fields->f_imm4, 0, pc, length);
 140       break;
 141     case XSTORMY16_OPERAND_IMM8 :
 142       print_normal (cd, info, fields->f_imm8, 0, pc, length);
 143       break;
 144     case XSTORMY16_OPERAND_IMM8SMALL :
 145       print_normal (cd, info, fields->f_imm8, 0, pc, length);
 146       break;
 147     case XSTORMY16_OPERAND_LMEM8 :
 148       print_normal (cd, info, fields->f_lmem8, 0|(1<<CGEN_OPERAND_ABS_ADDR), pc, length);
 149       break;
 150     case XSTORMY16_OPERAND_REL12 :
 151       print_normal (cd, info, fields->f_rel12, 0|(1<<CGEN_OPERAND_PCREL_ADDR), pc, length);
 152       break;
 153     case XSTORMY16_OPERAND_REL12A :
 154       print_normal (cd, info, fields->f_rel12a, 0|(1<<CGEN_OPERAND_PCREL_ADDR), pc, length);
 155       break;
 156     case XSTORMY16_OPERAND_REL8_2 :
 157       print_normal (cd, info, fields->f_rel8_2, 0|(1<<CGEN_OPERAND_PCREL_ADDR), pc, length);
 158       break;
 159     case XSTORMY16_OPERAND_REL8_4 :
 160       print_normal (cd, info, fields->f_rel8_4, 0|(1<<CGEN_OPERAND_PCREL_ADDR), pc, length);
 161       break;
 162     case XSTORMY16_OPERAND_WS2 :
 163       print_keyword (cd, info, & xstormy16_cgen_opval_h_wordsize, fields->f_op2m, 0);
 164       break;
 165
 166     default :
 167       /* xgettext:c-format */
 168       fprintf (stderr, _("Unrecognized field %d while printing insn.\n"),
 169                opindex);
 170     abort ();
 171   }
 172 }
 173
 174 cgen_print_fn * const xstormy16_cgen_print_handlers[] =
 175 {
 176   print_insn_normal,
 177 };
 178
 179
 180 void
 181 xstormy16_cgen_init_dis (CGEN_CPU_DESC cd)
 182 {
 183   xstormy16_cgen_init_opcode_table (cd);
 184   xstormy16_cgen_init_ibld_table (cd);
 185   cd->print_handlers = & xstormy16_cgen_print_handlers[0];
 186   cd->print_operand = xstormy16_cgen_print_operand;
 187 }
 188
 189 \f
 190 /* Default print handler.  */
 191
 192 static void
 193 print_normal (CGEN_CPU_DESC cd ATTRIBUTE_UNUSED,
 194               void *dis_info,
 195               long value,
 196               unsigned int attrs,
 197               bfd_vma pc ATTRIBUTE_UNUSED,
 198               int length ATTRIBUTE_UNUSED)
 199 {
 200   disassemble_info *info = (disassemble_info *) dis_info;
 201
 202 #ifdef CGEN_PRINT_NORMAL
 203   CGEN_PRINT_NORMAL (cd, info, value, attrs, pc, length);
 204 #endif
 205
 206   /* Print the operand as directed by the attributes.  */
 207   if (CGEN_BOOL_ATTR (attrs, CGEN_OPERAND_SEM_ONLY))
 208     ; /* nothing to do */
 209   else if (CGEN_BOOL_ATTR (attrs, CGEN_OPERAND_SIGNED))
 210     (*info->fprintf_func) (info->stream, "%ld", value);
 211   else
 212     (*info->fprintf_func) (info->stream, "0x%lx", value);
 213 }
 214
 215 /* Default address handler.  */
 216
 217 static void
 218 print_address (CGEN_CPU_DESC cd ATTRIBUTE_UNUSED,
 219                void *dis_info,
 220                bfd_vma value,
 221                unsigned int attrs,
 222                bfd_vma pc ATTRIBUTE_UNUSED,
 223                int length ATTRIBUTE_UNUSED)
 224 {
 225   disassemble_info *info = (disassemble_info *) dis_info;
 226
 227 #ifdef CGEN_PRINT_ADDRESS
 228   CGEN_PRINT_ADDRESS (cd, info, value, attrs, pc, length);
 229 #endif
 230
 231   /* Print the operand as directed by the attributes.  */
 232   if (CGEN_BOOL_ATTR (attrs, CGEN_OPERAND_SEM_ONLY))
 233     ; /* Nothing to do.  */
 234   else if (CGEN_BOOL_ATTR (attrs, CGEN_OPERAND_PCREL_ADDR))
 235     (*info->print_address_func) (value, info);
 236   else if (CGEN_BOOL_ATTR (attrs, CGEN_OPERAND_ABS_ADDR))
 237     (*info->print_address_func) (value, info);
 238   else if (CGEN_BOOL_ATTR (attrs, CGEN_OPERAND_SIGNED))
 239     (*info->fprintf_func) (info->stream, "%ld", (long) value);
 240   else
 241     (*info->fprintf_func) (info->stream, "0x%lx", (long) value);
 242 }
 243
 244 /* Keyword print handler.  */
 245
 246 static void
 247 print_keyword (CGEN_CPU_DESC cd ATTRIBUTE_UNUSED,
 248                void *dis_info,
 249                CGEN_KEYWORD *keyword_table,
 250                long value,
 251                unsigned int attrs ATTRIBUTE_UNUSED)
 252 {
 253   disassemble_info *info = (disassemble_info *) dis_info;
 254   const CGEN_KEYWORD_ENTRY *ke;
 255
 256   ke = cgen_keyword_lookup_value (keyword_table, value);
 257   if (ke != NULL)
 258     (*info->fprintf_func) (info->stream, "%s", ke->name);
 259   else
 260     (*info->fprintf_func) (info->stream, "???");
 261 }
 262 \f
 263 /* Default insn printer.
 264
 265    DIS_INFO is defined as `void *' so the disassembler needn't know anything
 266    about disassemble_info.  */
 267
 268 static void
 269 print_insn_normal (CGEN_CPU_DESC cd,
 270                    void *dis_info,
 271                    const CGEN_INSN *insn,
 272                    CGEN_FIELDS *fields,
 273                    bfd_vma pc,
 274                    int length)
 275 {
 276   const CGEN_SYNTAX *syntax = CGEN_INSN_SYNTAX (insn);
 277   disassemble_info *info = (disassemble_info *) dis_info;
 278   const CGEN_SYNTAX_CHAR_TYPE *syn;
 279
 280   CGEN_INIT_PRINT (cd);
 281
 282   for (syn = CGEN_SYNTAX_STRING (syntax); *syn; ++syn)
 283     {
 284       if (CGEN_SYNTAX_MNEMONIC_P (*syn))
 285         {
 286           (*info->fprintf_func) (info->stream, "%s", CGEN_INSN_MNEMONIC (insn));
 287           continue;
 288         }
 289       if (CGEN_SYNTAX_CHAR_P (*syn))
 290         {
 291           (*info->fprintf_func) (info->stream, "%c", CGEN_SYNTAX_CHAR (*syn));
 292           continue;
 293         }
 294
 295       /* We have an operand.  */
 296       xstormy16_cgen_print_operand (cd, CGEN_SYNTAX_FIELD (*syn), info,
 297                                  fields, CGEN_INSN_ATTRS (insn), pc, length);
 298     }
 299 }
 300 \f
 301 /* Subroutine of print_insn. Reads an insn into the given buffers and updates
 302    the extract info.
 303    Returns 0 if all is well, non-zero otherwise.  */
 304
 305 static int
 306 read_insn (CGEN_CPU_DESC cd ATTRIBUTE_UNUSED,
 307            bfd_vma pc,
 308            disassemble_info *info,
 309            bfd_byte *buf,
 310            int buflen,
 311            CGEN_EXTRACT_INFO *ex_info,
 312            unsigned long *insn_value)
 313 {
 314   int status = (*info->read_memory_func) (pc, buf, buflen, info);
 315
 316   if (status != 0)
 317     {
 318       (*info->memory_error_func) (status, pc, info);
 319       return -1;
 320     }
 321
 322   ex_info->dis_info = info;
 323   ex_info->valid = (1 << buflen) - 1;
 324   ex_info->insn_bytes = buf;
 325
 326   *insn_value = bfd_get_bits (buf, buflen * 8, info->endian == BFD_ENDIAN_BIG);
 327   return 0;
 328 }
 329
 330 /* Utility to print an insn.
 331    BUF is the base part of the insn, target byte order, BUFLEN bytes long.
 332    The result is the size of the insn in bytes or zero for an unknown insn
 333    or -1 if an error occurs fetching data (memory_error_func will have
 334    been called).  */
 335
 336 static int
 337 print_insn (CGEN_CPU_DESC cd,
 338             bfd_vma pc,
 339             disassemble_info *info,
 340             bfd_byte *buf,
 341             unsigned int buflen)
 342 {
 343   CGEN_INSN_INT insn_value;
 344   const CGEN_INSN_LIST *insn_list;
 345   CGEN_EXTRACT_INFO ex_info;
 346   int basesize;
 347
 348   /* Extract base part of instruction, just in case CGEN_DIS_* uses it. */
 349   basesize = cd->base_insn_bitsize < buflen * 8 ?
 350                                      cd->base_insn_bitsize : buflen * 8;
 351   insn_value = cgen_get_insn_value (cd, buf, basesize);
 352
 353
 354   /* Fill in ex_info fields like read_insn would.  Don't actually call
 355      read_insn, since the incoming buffer is already read (and possibly
 356      modified a la m32r).  */
 357   ex_info.valid = (1 << buflen) - 1;
 358   ex_info.dis_info = info;
 359   ex_info.insn_bytes = buf;
 360
 361   /* The instructions are stored in hash lists.
 362      Pick the first one and keep trying until we find the right one.  */
 363
 364   insn_list = CGEN_DIS_LOOKUP_INSN (cd, (char *) buf, insn_value);
 365   while (insn_list != NULL)
 366     {
 367       const CGEN_INSN *insn = insn_list->insn;
 368       CGEN_FIELDS fields;
 369       int length;
 370       unsigned long insn_value_cropped;
 371
 372 #ifdef CGEN_VALIDATE_INSN_SUPPORTED
 373       /* Not needed as insn shouldn't be in hash lists if not supported.  */
 374       /* Supported by this cpu?  */
 375       if (! xstormy16_cgen_insn_supported (cd, insn))
 376         {
 377           insn_list = CGEN_DIS_NEXT_INSN (insn_list);
 378           continue;
 379         }
 380 #endif
 381
 382       /* Basic bit mask must be correct.  */
 383       /* ??? May wish to allow target to defer this check until the extract
 384          handler.  */
 385
 386       /* Base size may exceed this instruction's size.  Extract the
 387          relevant part from the buffer. */
 388       if ((unsigned) (CGEN_INSN_BITSIZE (insn) / 8) < buflen &&
 389           (unsigned) (CGEN_INSN_BITSIZE (insn) / 8) <= sizeof (unsigned long))
 390         insn_value_cropped = bfd_get_bits (buf, CGEN_INSN_BITSIZE (insn),
 391                                            info->endian == BFD_ENDIAN_BIG);
 392       else
 393         insn_value_cropped = insn_value;
 394
 395       if ((insn_value_cropped & CGEN_INSN_BASE_MASK (insn))
 396           == CGEN_INSN_BASE_VALUE (insn))
 397         {
 398           /* Printing is handled in two passes.  The first pass parses the
 399              machine insn and extracts the fields.  The second pass prints
 400              them.  */
 401
 402           /* Make sure the entire insn is loaded into insn_value, if it
 403              can fit.  */
 404           if (((unsigned) CGEN_INSN_BITSIZE (insn) > cd->base_insn_bitsize) &&
 405               (unsigned) (CGEN_INSN_BITSIZE (insn) / 8) <= sizeof (unsigned long))
 406             {
 407               unsigned long full_insn_value;
 408               int rc = read_insn (cd, pc, info, buf,
 409                                   CGEN_INSN_BITSIZE (insn) / 8,
 410                                   & ex_info, & full_insn_value);
 411               if (rc != 0)
 412                 return rc;
 413               length = CGEN_EXTRACT_FN (cd, insn)
 414                 (cd, insn, &ex_info, full_insn_value, &fields, pc);
 415             }
 416           else
 417             length = CGEN_EXTRACT_FN (cd, insn)
 418               (cd, insn, &ex_info, insn_value_cropped, &fields, pc);
 419
 420           /* Length < 0 -> error.  */
 421           if (length < 0)
 422             return length;
 423           if (length > 0)
 424             {
 425               CGEN_PRINT_FN (cd, insn) (cd, info, insn, &fields, pc, length);
 426               /* Length is in bits, result is in bytes.  */
 427               return length / 8;
 428             }
 429         }
 430
 431       insn_list = CGEN_DIS_NEXT_INSN (insn_list);
 432     }
 433
 434   return 0;
 435 }
 436
 437 /* Default value for CGEN_PRINT_INSN.
 438    The result is the size of the insn in bytes or zero for an unknown insn
 439    or -1 if an error occured fetching bytes.  */
 440
 441 #ifndef CGEN_PRINT_INSN
 442 #define CGEN_PRINT_INSN default_print_insn
 443 #endif
 444
 445 static int
 446 default_print_insn (CGEN_CPU_DESC cd, bfd_vma pc, disassemble_info *info)
 447 {
 448   bfd_byte buf[CGEN_MAX_INSN_SIZE];
 449   int buflen;
 450   int status;
 451
 452   /* Attempt to read the base part of the insn.  */
 453   buflen = cd->base_insn_bitsize / 8;
 454   status = (*info->read_memory_func) (pc, buf, buflen, info);
 455
 456   /* Try again with the minimum part, if min < base.  */
 457   if (status != 0 && (cd->min_insn_bitsize < cd->base_insn_bitsize))
 458     {
 459       buflen = cd->min_insn_bitsize / 8;
 460       status = (*info->read_memory_func) (pc, buf, buflen, info);
 461     }
 462
 463   if (status != 0)
 464     {
 465       (*info->memory_error_func) (status, pc, info);
 466       return -1;
 467     }
 468
 469   return print_insn (cd, pc, info, buf, buflen);
 470 }
 471
 472 /* Main entry point.
 473    Print one instruction from PC on INFO->STREAM.
 474    Return the size of the instruction (in bytes).  */
 475
 476 typedef struct cpu_desc_list
 477 {
 478   struct cpu_desc_list *next;
 479   int isa;
 480   int mach;
 481   int endian;
 482   CGEN_CPU_DESC cd;
 483 } cpu_desc_list;
 484
 485 int
 486 print_insn_xstormy16 (bfd_vma pc, disassemble_info *info)
 487 {
 488   static cpu_desc_list *cd_list = 0;
 489   cpu_desc_list *cl = 0;
 490   static CGEN_CPU_DESC cd = 0;
 491   static int prev_isa;
 492   static int prev_mach;
 493   static int prev_endian;
 494   int length;
 495   int isa,mach;
 496   int endian = (info->endian == BFD_ENDIAN_BIG
 497                 ? CGEN_ENDIAN_BIG
 498                 : CGEN_ENDIAN_LITTLE);
 499   enum bfd_architecture arch;
 500
 501   /* ??? gdb will set mach but leave the architecture as "unknown" */
 502 #ifndef CGEN_BFD_ARCH
 503 #define CGEN_BFD_ARCH bfd_arch_xstormy16
 504 #endif
 505   arch = info->arch;
 506   if (arch == bfd_arch_unknown)
 507     arch = CGEN_BFD_ARCH;
 508
 509   /* There's no standard way to compute the machine or isa number
 510      so we leave it to the target.  */
 511 #ifdef CGEN_COMPUTE_MACH
 512   mach = CGEN_COMPUTE_MACH (info);
 513 #else
 514   mach = info->mach;
 515 #endif
 516
 517 #ifdef CGEN_COMPUTE_ISA
 518   isa = CGEN_COMPUTE_ISA (info);
 519 #else
 520   isa = info->insn_sets;
 521 #endif
 522
 523   /* If we've switched cpu's, try to find a handle we've used before */
 524   if (cd
 525       && (isa != prev_isa
 526           || mach != prev_mach
 527           || endian != prev_endian))
 528     {
 529       cd = 0;
 530       for (cl = cd_list; cl; cl = cl->next)
 531         {
 532           if (cl->isa == isa &&
 533               cl->mach == mach &&
 534               cl->endian == endian)
 535             {
 536               cd = cl->cd;
 537               break;
 538             }
 539         }
 540     }
 541
 542   /* If we haven't initialized yet, initialize the opcode table.  */
 543   if (! cd)
 544     {
 545       const bfd_arch_info_type *arch_type = bfd_lookup_arch (arch, mach);
 546       const char *mach_name;
 547
 548       if (!arch_type)
 549         abort ();
 550       mach_name = arch_type->printable_name;
 551
 552       prev_isa = isa;
 553       prev_mach = mach;
 554       prev_endian = endian;
 555       cd = xstormy16_cgen_cpu_open (CGEN_CPU_OPEN_ISAS, prev_isa,
 556                                  CGEN_CPU_OPEN_BFDMACH, mach_name,
 557                                  CGEN_CPU_OPEN_ENDIAN, prev_endian,
 558                                  CGEN_CPU_OPEN_END);
 559       if (!cd)
 560         abort ();
 561
 562       /* Save this away for future reference.  */
 563       cl = xmalloc (sizeof (struct cpu_desc_list));
 564       cl->cd = cd;
 565       cl->isa = isa;
 566       cl->mach = mach;
 567       cl->endian = endian;
 568       cl->next = cd_list;
 569       cd_list = cl;
 570
 571       xstormy16_cgen_init_dis (cd);
 572     }
 573
 574   /* We try to have as much common code as possible.
 575      But at this point some targets need to take over.  */
 576   /* ??? Some targets may need a hook elsewhere.  Try to avoid this,
 577      but if not possible try to move this hook elsewhere rather than
 578      have two hooks.  */
 579   length = CGEN_PRINT_INSN (cd, pc, info);
 580   if (length > 0)
 581     return length;
 582   if (length < 0)
 583     return -1;
 584
 585   (*info->fprintf_func) (info->stream, UNKNOWN_INSN_MSG);
 586   return cd->default_insn_bitsize / 8;
 587 }