/* CGEN generic disassembler support code.

Copyright (C) 1996, 1997 Free Software Foundation, Inc.

This file is part of the GNU Binutils and GDB, the GNU debugger.

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */

#include "config.h"
#include <stdio.h>
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#ifdef HAVE_STRINGS_H
#include <strings.h>
#endif
#include "ansidecl.h"
#include "libiberty.h"
#include "bfd.h"
#include "opcode/cgen.h"

/* This is not published as part of the public interface so we don't
   declare this in cgen.h.  */
extern CGEN_OPCODE_DATA *cgen_current_opcode_data;

/* Disassembler instruction hash table.  */
static CGEN_INSN_LIST **dis_hash_table;

void
cgen_dis_init ()
{
  if (dis_hash_table)
    {
      free (dis_hash_table);
      dis_hash_table = NULL;
    }
}

/* Build the disassembler instruction hash table.  */

static void
build_dis_hash_table ()
{
  int i;
  int big_p = cgen_current_endian == CGEN_ENDIAN_BIG;
  unsigned int hash;
  char buf[4];
  unsigned long value;
  int count = cgen_insn_count ();
  CGEN_OPCODE_DATA *data = cgen_current_opcode_data;
  CGEN_INSN_TABLE *insn_table = data->insn_table;
  unsigned int hash_size = insn_table->dis_hash_table_size;
  const CGEN_INSN *insn;
  CGEN_INSN_LIST *insn_lists,*new_insns;

  /* The space allocated for the hash table consists of two parts:
     the hash table and the hash lists.  */

  dis_hash_table = (CGEN_INSN_LIST **)
    xmalloc (hash_size * sizeof (CGEN_INSN_LIST *)
	     + count * sizeof (CGEN_INSN_LIST));
  memset (dis_hash_table, 0,
	  hash_size * sizeof (CGEN_INSN_LIST *)
	  + count * sizeof (CGEN_INSN_LIST));
  insn_lists = (CGEN_INSN_LIST *) (dis_hash_table + hash_size);

  /* Add compiled in insns.
     The table is scanned backwards as later additions are inserted in
     front of earlier ones and we want earlier ones to be prefered.
     We stop at the first one as it is a reserved entry.  */

  for (insn = insn_table->init_entries + insn_table->num_init_entries - 1;
       insn > insn_table->init_entries;
       --insn, ++insn_lists)
    {
      /* We don't know whether the target uses the buffer or the base insn
	 to hash on, so set both up.  */
      value = insn->syntax.value;
      switch (CGEN_INSN_BITSIZE (insn))
	{
	case 8:
	  buf[0] = value;
	  break;
	case 16:
	  if (big_p)
	    bfd_putb16 ((bfd_vma) value, buf);
	  else
	    bfd_putl16 ((bfd_vma) value, buf);
	  break;
	case 32:
	  if (big_p)
	    bfd_putb32 ((bfd_vma) value, buf);
	  else
	    bfd_putl32 ((bfd_vma) value, buf);
	  break;
	default:
	  abort ();
	}
      hash = (*insn_table->dis_hash) (buf, value);
      insn_lists->next = dis_hash_table[hash];
      insn_lists->insn = insn;
      dis_hash_table[hash] = insn_lists;
    }

  /* Add runtime added insns.
     ??? Currently later added insns will be prefered over earlier ones.
     Not sure this is a bug or not.  */
  for (new_insns = insn_table->new_entries;
       new_insns != NULL;
       new_insns = new_insns->next, ++insn_lists)
    {
      /* We don't know whether the target uses the buffer or the base insn
	 to hash on, so set both up.  */
      value = new_insns->insn->syntax.value;
      switch (CGEN_INSN_BITSIZE (new_insns->insn))
	{
	case 8:
	  buf[0] = value;
	  break;
	case 16:
	  if (big_p)
	    bfd_putb16 ((bfd_vma) value, buf);
	  else
	    bfd_putl16 ((bfd_vma) value, buf);
	  break;
	case 32:
	  if (big_p)
	    bfd_putb32 ((bfd_vma) value, buf);
	  else
	    bfd_putl32 ((bfd_vma) value, buf);
	  break;
	default:
	  abort ();
	}
      hash = (*insn_table->dis_hash) (buf, value);
      insn_lists->next = dis_hash_table[hash];
      insn_lists->insn = new_insns->insn;
      dis_hash_table[hash] = insn_lists;
    }
}

/* Return the first entry in the hash list for INSN.  */

CGEN_INSN_LIST *
cgen_dis_lookup_insn (buf, value)
     const char *buf;
     unsigned long value;
{
  unsigned int hash;

  if (dis_hash_table == NULL)
    build_dis_hash_table ();

  hash = (*cgen_current_opcode_data->insn_table->dis_hash) (buf, value);
  return dis_hash_table[hash];
}