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[/] [openrisc/] [trunk/] [gnu-src/] [gdb-6.8/] [opcodes/] [cgen-dis.c] - Blame information for rev 24

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1 24 jeremybenn
/* CGEN generic disassembler support code.
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   Copyright 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2007
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   Free Software Foundation, Inc.
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   This file is part of libopcodes.
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   This library is free software; you can redistribute it and/or modify
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   it under the terms of the GNU General Public License as published by
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   the Free Software Foundation; either version 3, or (at your option)
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   any later version.
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   It is distributed in the hope that it will be useful, but WITHOUT
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   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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   or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
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   License for more details.
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   You should have received a copy of the GNU General Public License along
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   with this program; if not, write to the Free Software Foundation, Inc.,
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   51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA.  */
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#include "sysdep.h"
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#include <stdio.h>
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#include "ansidecl.h"
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#include "libiberty.h"
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#include "bfd.h"
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#include "symcat.h"
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#include "opcode/cgen.h"
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static CGEN_INSN_LIST *  hash_insn_array        (CGEN_CPU_DESC, const CGEN_INSN *, int, int, CGEN_INSN_LIST **, CGEN_INSN_LIST *);
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static CGEN_INSN_LIST *  hash_insn_list         (CGEN_CPU_DESC, const CGEN_INSN_LIST *, CGEN_INSN_LIST **, CGEN_INSN_LIST *);
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static void              build_dis_hash_table   (CGEN_CPU_DESC);
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static int               count_decodable_bits   (const CGEN_INSN *);
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static void              add_insn_to_hash_chain (CGEN_INSN_LIST *,
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                                                 const CGEN_INSN *,
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                                                 CGEN_INSN_LIST **,
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                                                 unsigned int);
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/* Return the number of decodable bits in this insn.  */
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static int
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count_decodable_bits (const CGEN_INSN *insn)
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{
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  unsigned mask = CGEN_INSN_BASE_MASK (insn);
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  int bits = 0;
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  int m;
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  for (m = 1; m != 0; m <<= 1)
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    {
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      if (mask & m)
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        ++bits;
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    }
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  return bits;
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}
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/* Add an instruction to the hash chain.  */
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static void
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add_insn_to_hash_chain (CGEN_INSN_LIST *hentbuf,
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                        const CGEN_INSN *insn,
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                        CGEN_INSN_LIST **htable,
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                        unsigned int hash)
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{
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  CGEN_INSN_LIST *current_buf;
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  CGEN_INSN_LIST *previous_buf;
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  int insn_decodable_bits;
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  /* Add insns sorted by the number of decodable bits, in decreasing order.
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     This ensures that any insn which is a special case of another will be
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     checked first.  */
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  insn_decodable_bits = count_decodable_bits (insn);
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  previous_buf = NULL;
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  for (current_buf = htable[hash]; current_buf != NULL;
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       current_buf = current_buf->next)
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    {
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      int current_decodable_bits = count_decodable_bits (current_buf->insn);
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      if (insn_decodable_bits >= current_decodable_bits)
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        break;
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      previous_buf = current_buf;
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    }
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  /* Now insert the new insn.  */
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  hentbuf->insn = insn;
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  hentbuf->next = current_buf;
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  if (previous_buf == NULL)
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    htable[hash] = hentbuf;
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  else
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    previous_buf->next = hentbuf;
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}
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/* Subroutine of build_dis_hash_table to add INSNS to the hash table.
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   COUNT is the number of elements in INSNS.
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   ENTSIZE is sizeof (CGEN_IBASE) for the target.
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   ??? No longer used but leave in for now.
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   HTABLE points to the hash table.
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   HENTBUF is a pointer to sufficiently large buffer of hash entries.
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   The result is a pointer to the next entry to use.
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   The table is scanned backwards as additions are made to the front of the
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   list and we want earlier ones to be prefered.  */
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static CGEN_INSN_LIST *
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hash_insn_array (CGEN_CPU_DESC cd,
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                 const CGEN_INSN * insns,
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                 int count,
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                 int entsize ATTRIBUTE_UNUSED,
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                 CGEN_INSN_LIST ** htable,
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                 CGEN_INSN_LIST * hentbuf)
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{
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  int big_p = CGEN_CPU_ENDIAN (cd) == CGEN_ENDIAN_BIG;
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  int i;
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  for (i = count - 1; i >= 0; --i, ++hentbuf)
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    {
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      unsigned int hash;
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      char buf [4];
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      unsigned long value;
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      const CGEN_INSN *insn = &insns[i];
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      if (! (* cd->dis_hash_p) (insn))
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        continue;
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      /* We don't know whether the target uses the buffer or the base insn
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         to hash on, so set both up.  */
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      value = CGEN_INSN_BASE_VALUE (insn);
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      bfd_put_bits ((bfd_vma) value,
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                    buf,
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                    CGEN_INSN_MASK_BITSIZE (insn),
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                    big_p);
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      hash = (* cd->dis_hash) (buf, value);
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      add_insn_to_hash_chain (hentbuf, insn, htable, hash);
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    }
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  return hentbuf;
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}
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/* Subroutine of build_dis_hash_table to add INSNS to the hash table.
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   This function is identical to hash_insn_array except the insns are
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   in a list.  */
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static CGEN_INSN_LIST *
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hash_insn_list (CGEN_CPU_DESC cd,
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                const CGEN_INSN_LIST *insns,
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                CGEN_INSN_LIST **htable,
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                CGEN_INSN_LIST *hentbuf)
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{
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  int big_p = CGEN_CPU_ENDIAN (cd) == CGEN_ENDIAN_BIG;
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  const CGEN_INSN_LIST *ilist;
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  for (ilist = insns; ilist != NULL; ilist = ilist->next, ++ hentbuf)
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    {
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      unsigned int hash;
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      char buf[4];
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      unsigned long value;
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      if (! (* cd->dis_hash_p) (ilist->insn))
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        continue;
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      /* We don't know whether the target uses the buffer or the base insn
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         to hash on, so set both up.  */
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      value = CGEN_INSN_BASE_VALUE (ilist->insn);
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      bfd_put_bits((bfd_vma) value,
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                   buf,
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                   CGEN_INSN_MASK_BITSIZE (ilist->insn),
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                   big_p);
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      hash = (* cd->dis_hash) (buf, value);
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      add_insn_to_hash_chain (hentbuf, ilist->insn, htable, hash);
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    }
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  return hentbuf;
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}
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/* Build the disassembler instruction hash table.  */
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static void
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build_dis_hash_table (CGEN_CPU_DESC cd)
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{
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  int count = cgen_insn_count (cd) + cgen_macro_insn_count (cd);
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  CGEN_INSN_TABLE *insn_table = & cd->insn_table;
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  CGEN_INSN_TABLE *macro_insn_table = & cd->macro_insn_table;
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  unsigned int hash_size = cd->dis_hash_size;
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  CGEN_INSN_LIST *hash_entry_buf;
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  CGEN_INSN_LIST **dis_hash_table;
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  CGEN_INSN_LIST *dis_hash_table_entries;
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  /* The space allocated for the hash table consists of two parts:
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     the hash table and the hash lists.  */
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  dis_hash_table = (CGEN_INSN_LIST **)
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    xmalloc (hash_size * sizeof (CGEN_INSN_LIST *));
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  memset (dis_hash_table, 0, hash_size * sizeof (CGEN_INSN_LIST *));
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  dis_hash_table_entries = hash_entry_buf = (CGEN_INSN_LIST *)
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    xmalloc (count * sizeof (CGEN_INSN_LIST));
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  /* Add compiled in insns.
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     Don't include the first one as it is a reserved entry.  */
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  /* ??? It was the end of all hash chains, and also the special
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     "invalid insn" marker.  May be able to do it differently now.  */
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  hash_entry_buf = hash_insn_array (cd,
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                                    insn_table->init_entries + 1,
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                                    insn_table->num_init_entries - 1,
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                                    insn_table->entry_size,
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                                    dis_hash_table, hash_entry_buf);
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  /* Add compiled in macro-insns.  */
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  hash_entry_buf = hash_insn_array (cd, macro_insn_table->init_entries,
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                                    macro_insn_table->num_init_entries,
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                                    macro_insn_table->entry_size,
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                                    dis_hash_table, hash_entry_buf);
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  /* Add runtime added insns.
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     Later added insns will be prefered over earlier ones.  */
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  hash_entry_buf = hash_insn_list (cd, insn_table->new_entries,
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                                   dis_hash_table, hash_entry_buf);
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  /* Add runtime added macro-insns.  */
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  hash_insn_list (cd, macro_insn_table->new_entries,
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                  dis_hash_table, hash_entry_buf);
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  cd->dis_hash_table = dis_hash_table;
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  cd->dis_hash_table_entries = dis_hash_table_entries;
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}
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/* Return the first entry in the hash list for INSN.  */
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CGEN_INSN_LIST *
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cgen_dis_lookup_insn (CGEN_CPU_DESC cd, const char * buf, CGEN_INSN_INT value)
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{
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  unsigned int hash;
233
 
234
  if (cd->dis_hash_table == NULL)
235
    build_dis_hash_table (cd);
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237
  hash = (* cd->dis_hash) (buf, value);
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  return cd->dis_hash_table[hash];
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}

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