/* Native-dependent code for VAX UNIXen (including older BSD's).

   Copyright (C) 2004, 2005, 2007, 2008, 2009, 2010, 2011
   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 3 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, see <http://www.gnu.org/licenses/>.  */

#include "defs.h"
#include "inferior.h"

#include "gdb_assert.h"
#include <sys/types.h>
#include <sys/dir.h>
#include <sys/user.h>

#ifdef HAVE_SYS_PTRACE_H
#include <sys/ptrace.h>
#endif

#ifndef PT_READ_U
#define PT_READ_U 3
#endif

#ifdef SYS_REG_H
/* UNIX 32V and derivatives (including 3BSD).  */
#include <sys/reg.h>
#else
/* 4.2BSD and derivatives.  */
#include <machine/reg.h>
#endif

#include "vax-tdep.h"
#include "inf-ptrace.h"

/* Address of the user structure.  This is the value for 32V; 3BSD
   uses a different value, but hey, who's still using those systems?  */
static CORE_ADDR vax_kernel_u_addr = 0x80020000;

/* Location of the user's stored registers; usage is `u.u_ar0[XX]'.
   For 4.2BSD and ULTRIX these are negative!  See <machine/reg.h>.  */
static int vax_register_index[] =
{
  R0, R1, R2, R3, R4, R5,
  R6, R7, R8, R9, R10, R11,
  AP, FP, SP, PC, PS
};

static CORE_ADDR
vax_register_u_addr (CORE_ADDR u_ar0, int regnum)
{
  gdb_assert (regnum >= 0 && regnum < ARRAY_SIZE (vax_register_index));

  /* Type is `int *u_ar0'.  See <sys/user.h>.  */
  return u_ar0 + vax_register_index[regnum - VAX_R0_REGNUM] * 4;
}

static CORE_ADDR
vax_register_u_offset (struct gdbarch *gdbarch, int regnum, int store_p)
{
  size_t u_ar0_offset = offsetof (struct user, u_ar0);
  CORE_ADDR u_ar0;
  int pid;

  errno = 0;
  pid = PIDGET (inferior_ptid);
  u_ar0 = ptrace (PT_READ_U, pid, u_ar0_offset, 0);
  if (errno)
    perror_with_name (_("Unable to determine location of registers"));

  return vax_register_u_addr (u_ar0, regnum) - vax_kernel_u_addr;
}


#include <nlist.h>

#ifndef _PATH_UNIX
#define _PATH_UNIX "/vmunix"
#endif

/* Provide a prototype to silence -Wmissing-prototypes.  */
void _initialize_vax_nat (void);

void
_initialize_vax_nat (void)
{
  struct nlist names[2];

  names[0].n_name = "_u";
  names[1].n_name = NULL;
  if (nlist (_PATH_UNIX, names) == 0)
    vax_kernel_u_addr = names[0].n_value;

  add_target (inf_ptrace_trad_target (vax_register_u_offset));
}