/* Copyright (C) 2001 Free Software Foundation, Inc.
 *
 * 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 software; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
 * Boston, MA 02111-1307 USA
 *
 * As a special exception, the Free Software Foundation gives permission
 * for additional uses of the text contained in its release of GUILE.
 *
 * The exception is that, if you link the GUILE library with other files
 * to produce an executable, this does not by itself cause the
 * resulting executable to be covered by the GNU General Public License.
 * Your use of that executable is in no way restricted on account of
 * linking the GUILE library code into it.
 *
 * This exception does not however invalidate any other reasons why
 * the executable file might be covered by the GNU General Public License.
 *
 * This exception applies only to the code released by the
 * Free Software Foundation under the name GUILE.  If you copy
 * code from other Free Software Foundation releases into a copy of
 * GUILE, as the General Public License permits, the exception does
 * not apply to the code that you add in this way.  To avoid misleading
 * anyone as to the status of such modified files, you must delete
 * this exception notice from them.
 *
 * If you write modifications of your own for GUILE, it is your choice
 * whether to permit this exception to apply to your modifications.
 * If you do not wish that, delete this exception notice.  */

#if HAVE_CONFIG_H
#  include <config.h>
#endif

#include <string.h>
#include "vm-bootstrap.h"
#include "instructions.h"

struct scm_instruction {
  enum scm_opcode opcode;	/* opcode */
  const char *name;		/* instruction name */
  signed char len;		/* Instruction length.  This may be -1 for
				   the loader (see the `VM_LOADER'
				   macro).  */
  signed char npop;		/* The number of values popped.  This may be
				   -1 for insns like `call' which can take
				   any number of arguments.  */
  char npush;			/* the number of values pushed */
  SCM symname;                  /* filled in later */
};

#define SCM_VALIDATE_LOOKUP_INSTRUCTION(pos, var, cvar)               \
  do {                                                                \
    cvar = scm_lookup_instruction_by_name (var);                      \
    SCM_ASSERT_TYPE (cvar, var, pos, FUNC_NAME, "INSTRUCTION_P");     \
  } while (0)


static struct scm_instruction*
fetch_instruction_table ()
{
  static struct scm_instruction *table = NULL;

  if (SCM_UNLIKELY (!table))
    {
      size_t bytes = scm_op_last * sizeof(struct scm_instruction);
      int i;
      table = malloc (bytes);
      memset (table, 0, bytes);
#define VM_INSTRUCTION_TO_TABLE 1
#include "vm-expand.h"
#include "vm-i-system.i"
#include "vm-i-scheme.i"
#include "vm-i-loader.i"
#undef VM_INSTRUCTION_TO_TABLE
      for (i = 0; i < scm_op_last; i++)
        {
          table[i].opcode = i;
          if (table[i].name)
            table[i].symname = scm_from_locale_symbol (table[i].name);
          else
            table[i].symname = SCM_BOOL_F;
        }
    }
  return table;
}

static struct scm_instruction *
scm_lookup_instruction_by_name (SCM name)
{
  static SCM instructions_by_name = SCM_BOOL_F;
  struct scm_instruction *table = fetch_instruction_table ();
  SCM op;

  if (SCM_UNLIKELY (SCM_FALSEP (instructions_by_name)))
    { 
      int i;
      instructions_by_name = scm_make_hash_table (SCM_I_MAKINUM (scm_op_last));
      for (i = 0; i < scm_op_last; i++)
        if (scm_is_true (table[i].symname))
          scm_hashq_set_x (instructions_by_name, table[i].symname,
                           SCM_I_MAKINUM (i));
      instructions_by_name = scm_permanent_object (instructions_by_name);
    }
  
  op = scm_hashq_ref (instructions_by_name, name, SCM_UNDEFINED);
  if (SCM_I_INUMP (op))
    return &table[SCM_I_INUM (op)];

  return NULL;
}


/* Scheme interface */

SCM_DEFINE (scm_instruction_list, "instruction-list", 0, 0, 0,
	    (void),
	    "")
#define FUNC_NAME s_scm_instruction_list
{
  SCM list = SCM_EOL;
  struct scm_instruction *ip;
  for (ip = fetch_instruction_table (); ip->opcode != scm_op_last; ip++)
    if (ip->name)
      list = scm_cons (ip->symname, list);
  return scm_reverse_x (list, SCM_EOL);
}
#undef FUNC_NAME

SCM_DEFINE (scm_instruction_p, "instruction?", 1, 0, 0,
	    (SCM obj),
	    "")
#define FUNC_NAME s_scm_instruction_p
{
  return SCM_BOOL (scm_lookup_instruction_by_name (obj));
}
#undef FUNC_NAME

SCM_DEFINE (scm_instruction_length, "instruction-length", 1, 0, 0,
	    (SCM inst),
	    "")
#define FUNC_NAME s_scm_instruction_length
{
  struct scm_instruction *ip;
  SCM_VALIDATE_LOOKUP_INSTRUCTION (1, inst, ip);
  return SCM_I_MAKINUM (ip->len);
}
#undef FUNC_NAME

SCM_DEFINE (scm_instruction_pops, "instruction-pops", 1, 0, 0,
	    (SCM inst),
	    "")
#define FUNC_NAME s_scm_instruction_pops
{
  struct scm_instruction *ip;
  SCM_VALIDATE_LOOKUP_INSTRUCTION (1, inst, ip);
  return SCM_I_MAKINUM (ip->npop);
}
#undef FUNC_NAME

SCM_DEFINE (scm_instruction_pushes, "instruction-pushes", 1, 0, 0,
	    (SCM inst),
	    "")
#define FUNC_NAME s_scm_instruction_pushes
{
  struct scm_instruction *ip;
  SCM_VALIDATE_LOOKUP_INSTRUCTION (1, inst, ip);
  return SCM_I_MAKINUM (ip->npush);
}
#undef FUNC_NAME

SCM_DEFINE (scm_instruction_to_opcode, "instruction->opcode", 1, 0, 0,
	    (SCM inst),
	    "")
#define FUNC_NAME s_scm_instruction_to_opcode
{
  struct scm_instruction *ip;
  SCM_VALIDATE_LOOKUP_INSTRUCTION (1, inst, ip);
  return SCM_I_MAKINUM (ip->opcode);
}
#undef FUNC_NAME

SCM_DEFINE (scm_opcode_to_instruction, "opcode->instruction", 1, 0, 0,
	    (SCM op),
	    "")
#define FUNC_NAME s_scm_opcode_to_instruction
{
  int opcode;
  SCM ret = SCM_BOOL_F;

  SCM_MAKE_VALIDATE (1, op, I_INUMP);
  opcode = SCM_I_INUM (op);

  if (opcode < scm_op_last)
    ret = fetch_instruction_table ()[opcode].symname;

  if (scm_is_false (ret))
    scm_wrong_type_arg_msg (FUNC_NAME, 1, op, "INSTRUCTION_P");

  return ret;
}
#undef FUNC_NAME

void
scm_bootstrap_instructions (void)
{
}

void
scm_init_instructions (void)
{
  scm_bootstrap_vm ();

#ifndef SCM_MAGIC_SNARFER
#include "instructions.x"
#endif
}

/*
  Local Variables:
  c-file-style: "gnu"
  End:
*/