/* CGEN generic opcode support.

   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 "sysdep.h"
#include <ctype.h>
#include <stdio.h>
#include "ansidecl.h"
#include "libiberty.h"
#include "bfd.h"
#include "opcode/cgen.h"

/* State variables.
   These record the state of the currently selected cpu, machine, endian, etc.
   They are set by cgen_set_cpu.  */

/* Current opcode data.  */
CGEN_OPCODE_DATA *cgen_current_opcode_data;

/* Current machine (a la BFD machine number).  */
int cgen_current_mach;

/* Current endian.  */
enum cgen_endian cgen_current_endian = CGEN_ENDIAN_UNKNOWN;

/* FIXME: To support multiple architectures, we need to return a handle
   to the state set up by this function, and pass the handle back to the
   other functions.  Later.  */

void
cgen_set_cpu (data, mach, endian)
     CGEN_OPCODE_DATA *data;
     int mach;
     enum cgen_endian endian;
{
  cgen_current_opcode_data = data;
  cgen_current_mach = mach;
  cgen_current_endian = endian;

#if 0 /* This isn't done here because it would put assembler support in the
	 disassembler, etc.  The caller is required to call these after calling
	 us.  */
  /* Reset the hash tables.  */
  cgen_asm_init ();
  cgen_dis_init ();
#endif
}

static unsigned int hash_keyword_name
  PARAMS ((const CGEN_KEYWORD *, const char *, int));
static unsigned int hash_keyword_value
  PARAMS ((const CGEN_KEYWORD *, unsigned int));
static void build_keyword_hash_tables
  PARAMS ((CGEN_KEYWORD *));

/* Return number of hash table entries to use for N elements.  */
#define KEYWORD_HASH_SIZE(n) ((n) <= 31 ? 17 : 31)

/* Look up *NAMEP in the keyword table KT.
   The result is the keyword entry or NULL if not found.  */

const CGEN_KEYWORD_ENTRY *
cgen_keyword_lookup_name (kt, name)
     CGEN_KEYWORD *kt;
     const char *name;
{
  const CGEN_KEYWORD_ENTRY *ke;
  const char *p,*n;

  if (kt->name_hash_table == NULL)
    build_keyword_hash_tables (kt);

  ke = kt->name_hash_table[hash_keyword_name (kt, name, 0)];

  /* We do case insensitive comparisons.
     If that ever becomes a problem, add an attribute that denotes
     "do case sensitive comparisons".  */

  while (ke != NULL)
    {
      n = name;
      p = ke->name;

      while (*p
	     && (*p == *n
		 || (isalpha (*p) && tolower (*p) == tolower (*n))))
	++n, ++p;

      if (!*p && !*n)
	return ke;

      ke = ke->next_name;
    }

  if (kt->null_entry)
    return kt->null_entry;
  return NULL;
}

/* Look up VALUE in the keyword table KT.
   The result is the keyword entry or NULL if not found.  */

const CGEN_KEYWORD_ENTRY *
cgen_keyword_lookup_value (kt, value)
     CGEN_KEYWORD *kt;
     int value;
{
  const CGEN_KEYWORD_ENTRY *ke;

  if (kt->name_hash_table == NULL)
    build_keyword_hash_tables (kt);

  ke = kt->value_hash_table[hash_keyword_value (kt, value)];

  while (ke != NULL)
    {
      if (value == ke->value)
	return ke;
      ke = ke->next_value;
    }

  return NULL;
}

/* Add an entry to a keyword table.  */

void
cgen_keyword_add (kt, ke)
     CGEN_KEYWORD *kt;
     CGEN_KEYWORD_ENTRY *ke;
{
  unsigned int hash;

  if (kt->name_hash_table == NULL)
    build_keyword_hash_tables (kt);

  hash = hash_keyword_name (kt, ke->name, 0);
  ke->next_name = kt->name_hash_table[hash];
  kt->name_hash_table[hash] = ke;

  hash = hash_keyword_value (kt, ke->value);
  ke->next_value = kt->value_hash_table[hash];
  kt->value_hash_table[hash] = ke;

  if (ke->name[0] == 0)
    kt->null_entry = ke;
}

/* FIXME: Need function to return count of keywords.  */

/* Initialize a keyword table search.
   SPEC is a specification of what to search for.
   A value of NULL means to find every keyword.
   Currently NULL is the only acceptable value [further specification
   deferred].
   The result is an opaque data item used to record the search status.
   It is passed to each call to cgen_keyword_search_next.  */

CGEN_KEYWORD_SEARCH
cgen_keyword_search_init (kt, spec)
     CGEN_KEYWORD *kt;
     const char *spec;
{
  CGEN_KEYWORD_SEARCH search;

  /* FIXME: Need to specify format of PARAMS.  */
  if (spec != NULL)
    abort ();

  if (kt->name_hash_table == NULL)
    build_keyword_hash_tables (kt);

  search.table = kt;
  search.spec = spec;
  search.current_hash = 0;
  search.current_entry = NULL;
  return search;
}

/* Return the next keyword specified by SEARCH.
   The result is the next entry or NULL if there are no more.  */

const CGEN_KEYWORD_ENTRY *
cgen_keyword_search_next (search)
     CGEN_KEYWORD_SEARCH *search;
{
  const CGEN_KEYWORD_ENTRY *ke;

  /* Has search finished?  */
  if (search->current_hash == search->table->hash_table_size)
    return NULL;

  /* Search in progress?  */
  if (search->current_entry != NULL
      /* Anything left on this hash chain?  */
      && search->current_entry->next_name != NULL)
    {
      search->current_entry = search->current_entry->next_name;
      return search->current_entry;
    }

  /* Move to next hash chain [unless we haven't started yet].  */
  if (search->current_entry != NULL)
    ++search->current_hash;

  while (search->current_hash < search->table->hash_table_size)
    {
      search->current_entry = search->table->name_hash_table[search->current_hash];
      if (search->current_entry != NULL)
	return search->current_entry;
      ++search->current_hash;
    }

  return NULL;
}

/* Return first entry in hash chain for NAME.
   If CASE_SENSITIVE_P is non-zero, return a case sensitive hash.  */

static unsigned int
hash_keyword_name (kt, name, case_sensitive_p)
     const CGEN_KEYWORD *kt;
     const char *name;
     int case_sensitive_p;
{
  unsigned int hash;

  if (case_sensitive_p)
    for (hash = 0; *name; ++name)
      hash = (hash * 97) + (unsigned char) *name;
  else
    for (hash = 0; *name; ++name)
      hash = (hash * 97) + (unsigned char) tolower (*name);
  return hash % kt->hash_table_size;
}

/* Return first entry in hash chain for VALUE.  */

static unsigned int
hash_keyword_value (kt, value)
     const CGEN_KEYWORD *kt;
     unsigned int value;
{
  return value % kt->hash_table_size;
}

/* Build a keyword table's hash tables.
   We probably needn't build the value hash table for the assembler when
   we're using the disassembler, but we keep things simple.  */

static void
build_keyword_hash_tables (kt)
     CGEN_KEYWORD *kt;
{
  int i;
  /* Use the number of compiled in entries as an estimate for the
     typical sized table [not too many added at runtime].  */
  unsigned int size = KEYWORD_HASH_SIZE (kt->num_init_entries);

  kt->hash_table_size = size;
  kt->name_hash_table = (CGEN_KEYWORD_ENTRY **)
    xmalloc (size * sizeof (CGEN_KEYWORD_ENTRY *));
  memset (kt->name_hash_table, 0, size * sizeof (CGEN_KEYWORD_ENTRY *));
  kt->value_hash_table = (CGEN_KEYWORD_ENTRY **)
    xmalloc (size * sizeof (CGEN_KEYWORD_ENTRY *));
  memset (kt->value_hash_table, 0, size * sizeof (CGEN_KEYWORD_ENTRY *));

  /* The table is scanned backwards as we want keywords appearing earlier to
     be prefered over later ones.  */
  for (i = kt->num_init_entries - 1; i >= 0; --i)
    cgen_keyword_add (kt, &kt->init_entries[i]);
}

/* Hardware support.  */

CGEN_HW_ENTRY *
cgen_hw_lookup (name)
     const char *name;
{
  CGEN_HW_ENTRY *hw = cgen_current_opcode_data->hw_list;

  while (hw != NULL)
    {
      if (strcmp (name, hw->name) == 0)
	return hw;
      hw = hw->next;
    }

  return NULL;
}

/* Instruction support.  */

/* Return number of instructions.  This includes any added at runtime.  */

int
cgen_insn_count ()
{
  int count = cgen_current_opcode_data->insn_table->num_init_entries;
  CGEN_INSN_LIST *insn = cgen_current_opcode_data->insn_table->new_entries;

  for ( ; insn != NULL; insn = insn->next)
    ++count;

  return count;
}
