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/* Intel 386 native support for SYSV systems (pre-SVR4).

   Copyright 1988, 1989, 1991, 1992, 1993, 1994, 1995, 1996, 1998, 1999,

   2000 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"

#ifdef HAVE_PTRACE_H

#include <ptrace.h>

#else

#ifdef HAVE_SYS_PTRACE_H

#include <sys/ptrace.h>

#endif

#endif

#include "frame.h"

#include "inferior.h"

#include "language.h"

#include "gdbcore.h"

#ifdef USG

#include <sys/types.h>

#endif

#include <sys/param.h>

#include <sys/dir.h>

#include <signal.h>

#include <sys/user.h>

#include <sys/ioctl.h>

#include <fcntl.h>

/* FIXME: The following used to be just "#include <sys/debugreg.h>", but

 * the the Linux 2.1.x kernel and glibc 2.0.x are not in sync; including

 * <sys/debugreg.h> will result in an error.  With luck, these losers

 * will get their act together and we can trash this hack in the near future.

 * --jsm 1998-10-21

 */

#ifdef TARGET_HAS_HARDWARE_WATCHPOINTS

#ifdef HAVE_ASM_DEBUGREG_H

#include <asm/debugreg.h>

#else

#include <sys/debugreg.h>

#endif

#endif

#include <sys/file.h>

#include "gdb_stat.h"

#ifdef HAVE_SYS_REG_H

#include <sys/reg.h>

#endif

#include "floatformat.h"

#include "target.h"

/* this table must line up with REGISTER_NAMES in tm-i386v.h */

/* symbols like 'EAX' come from <sys/reg.h> */

static int regmap[] =

{

  EAX, ECX, EDX, EBX,

  UESP, EBP, ESI, EDI,

  EIP, EFL, CS, SS,

  DS, ES, FS, GS,

};

/* blockend is the value of u.u_ar0, and points to the

 * place where GS is stored

 */

int

i386_register_u_addr (int blockend, int regnum)

{

  struct user u;

  int fpstate;

  int ubase;

  ubase = blockend;

  /* FIXME:  Should have better way to test floating point range */

  if (regnum >= FP0_REGNUM && regnum <= (FP0_REGNUM + 7))

    {

#ifdef KSTKSZ                   /* SCO, and others? */

      ubase += 4 * (SS + 1) - KSTKSZ;

      fpstate = ubase + ((char *) &u.u_fps.u_fpstate - (char *) &u);

      return (fpstate + 0x1c + 10 * (regnum - FP0_REGNUM));

#else

      fpstate = ubase + ((char *) &u.i387.st_space - (char *) &u);

      return (fpstate + 10 * (regnum - FP0_REGNUM));

#endif

    }

  else

    {

      return (ubase + 4 * regmap[regnum]);

    }

}

int

kernel_u_size (void)

{

  return (sizeof (struct user));

}

#ifdef TARGET_HAS_HARDWARE_WATCHPOINTS

#if !defined (offsetof)

#define offsetof(TYPE, MEMBER) ((unsigned long) &((TYPE *)0)->MEMBER)

#endif

/* Record the value of the debug control register.  */

static int debug_control_mirror;

/* Record which address associates with which register.  */

static CORE_ADDR address_lookup[DR_LASTADDR - DR_FIRSTADDR + 1];

static int

i386_insert_aligned_watchpoint (int, CORE_ADDR, CORE_ADDR, int, int);

static int

i386_insert_nonaligned_watchpoint (int, CORE_ADDR, CORE_ADDR, int, int);

/* Insert a watchpoint.  */

int

i386_insert_watchpoint (int pid, CORE_ADDR addr, int len, int rw)

{

  return i386_insert_aligned_watchpoint (pid, addr, addr, len, rw);

}

static int

i386_insert_aligned_watchpoint (int pid, CORE_ADDR waddr, CORE_ADDR addr,

                                int len, int rw)

{

  int i;

  int read_write_bits, len_bits;

  int free_debug_register;

  int register_number;

  /* Look for a free debug register.  */

  for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)

    {

      if (address_lookup[i - DR_FIRSTADDR] == 0)

        break;

    }

  /* No more debug registers!  */

  if (i > DR_LASTADDR)

    return -1;

  read_write_bits = (rw & 1) ? DR_RW_READ : DR_RW_WRITE;

  if (len == 1)

    len_bits = DR_LEN_1;

  else if (len == 2)

    {

      if (addr % 2)

        return i386_insert_nonaligned_watchpoint (pid, waddr, addr, len, rw);

      len_bits = DR_LEN_2;

    }

  else if (len == 4)

    {

      if (addr % 4)

        return i386_insert_nonaligned_watchpoint (pid, waddr, addr, len, rw);

      len_bits = DR_LEN_4;

    }

  else

    return i386_insert_nonaligned_watchpoint (pid, waddr, addr, len, rw);

  free_debug_register = i;

  register_number = free_debug_register - DR_FIRSTADDR;

  debug_control_mirror |=

    ((read_write_bits | len_bits)

     << (DR_CONTROL_SHIFT + DR_CONTROL_SIZE * register_number));

  debug_control_mirror |=

    (1 << (DR_LOCAL_ENABLE_SHIFT + DR_ENABLE_SIZE * register_number));

  debug_control_mirror |= DR_LOCAL_SLOWDOWN;

  debug_control_mirror &= ~DR_CONTROL_RESERVED;

  ptrace (6, pid, offsetof (struct user, u_debugreg[DR_CONTROL]),

          debug_control_mirror);

  ptrace (6, pid, offsetof (struct user, u_debugreg[free_debug_register]),

          addr);

  /* Record where we came from.  */

  address_lookup[register_number] = addr;

  return 0;

}

static int

i386_insert_nonaligned_watchpoint (int pid, CORE_ADDR waddr, CORE_ADDR addr,

                                   int len, int rw)

{

  int align;

  int size;

  int rv;

  static int size_try_array[4][4] =

  {

    { 1, 1, 1, 1 },             /* trying size one */

    { 2, 1, 2, 1 },             /* trying size two */

    { 2, 1, 2, 1 },             /* trying size three */

    { 4, 1, 2, 1 }              /* trying size four */

  };

  rv = 0;

  while (len > 0)

    {

      align = addr % 4;

      /* Four is the maximum length for 386.  */

      size = size_try_array[len > 4 ? 3 : len - 1][align];

      rv = i386_insert_aligned_watchpoint (pid, waddr, addr, size, rw);

      if (rv)

        {

          i386_remove_watchpoint (pid, waddr, size);

          return rv;

        }

      addr += size;

      len -= size;

    }

  return rv;

}

/* Remove a watchpoint.  */

int

i386_remove_watchpoint (int pid, CORE_ADDR addr, int len)

{

  int i;

  int register_number;

  for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)

    {

      register_number = i - DR_FIRSTADDR;

      if (address_lookup[register_number] == addr)

        {

          debug_control_mirror &=

            ~(1 << (DR_LOCAL_ENABLE_SHIFT + DR_ENABLE_SIZE * register_number));

          address_lookup[register_number] = 0;

        }

    }

  ptrace (6, pid, offsetof (struct user, u_debugreg[DR_CONTROL]),

          debug_control_mirror);

  ptrace (6, pid, offsetof (struct user, u_debugreg[DR_STATUS]), 0);

  return 0;

}

/* Check if stopped by a watchpoint.  */

CORE_ADDR

i386_stopped_by_watchpoint (int pid)

{

  int i;

  int status;

  status = ptrace (3, pid, offsetof (struct user, u_debugreg[DR_STATUS]), 0);

  ptrace (6, pid, offsetof (struct user, u_debugreg[DR_STATUS]), 0);

  for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)

    {

      if (status & (1 << (i - DR_FIRSTADDR)))

        return address_lookup[i - DR_FIRSTADDR];

    }

  return 0;

}

#endif /* TARGET_HAS_HARDWARE_WATCHPOINTS */