/* Print NS 32000 instructions for GDB, the GNU debugger.
   Copyright 1986, 1988, 1991, 1992, 1994, 1995
   Free Software Foundation, Inc.

This file is part of GDB.

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 of the License, 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 "defs.h"

void
_initialize_ns32k_tdep ()
{
  tm_print_insn = print_insn_ns32k;
}

sign_extend (value, bits)
{
  value = value & ((1 << bits) - 1);
  return (value & (1 << (bits-1))
	  ? value | (~((1 << bits) - 1))
	  : value);
}

void
flip_bytes (ptr, count)
     char *ptr;
     int count;
{
  char tmp;

  while (count > 0)
    {
      tmp = *ptr;
      ptr[0] = ptr[count-1];
      ptr[count-1] = tmp;
      ptr++;
      count -= 2;
    }
}

/* Return the number of locals in the current frame given a pc
   pointing to the enter instruction.  This is used in the macro
   FRAME_FIND_SAVED_REGS.  */

int
ns32k_localcount (enter_pc)
     CORE_ADDR enter_pc;
{
  unsigned char localtype;
  int localcount;

  localtype = read_memory_integer (enter_pc+2, 1);
  if ((localtype & 0x80) == 0)
    localcount = localtype;
  else if ((localtype & 0xc0) == 0x80)
    localcount = (((localtype & 0x3f) << 8)
		  | (read_memory_integer (enter_pc+3, 1) & 0xff));
  else
    localcount = (((localtype & 0x3f) << 24)
		  | ((read_memory_integer (enter_pc+3, 1) & 0xff) << 16)
		  | ((read_memory_integer (enter_pc+4, 1) & 0xff) << 8 )
		  | (read_memory_integer (enter_pc+5, 1) & 0xff));
  return localcount;
}


/* Nonzero if instruction at PC is a return instruction.  */

static int
ns32k_about_to_return (pc)
     CORE_ADDR pc;
{
  return (read_memory_integer (pc, 1) == 0x12);
}


/*
 * Get the address of the enter opcode for the function
 * containing PC, if there is an enter for the function,
 * and if the pc is between the enter and exit.
 * Returns positive address if pc is between enter/exit,
 * 1 if pc before enter or after exit, 0 otherwise.
 */

CORE_ADDR
ns32k_get_enter_addr (pc)
     CORE_ADDR pc;
{
  CORE_ADDR enter_addr;
  unsigned char op;

  if (pc == 0)
    return 0;

  if (ns32k_about_to_return (pc))
    return 1;		/* after exit */

  enter_addr = get_pc_function_start (pc);

  if (pc == enter_addr) 
    return 1;		/* before enter */

  op = read_memory_integer (enter_addr, 1);

  if (op != 0x82)
    return 0;		/* function has no enter/exit */

  return enter_addr;	/* pc is between enter and exit */
}