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/* Target-dependent code for NetBSD/i386, for GDB.

   Copyright 1988, 1989, 1991, 1992, 1994, 1996, 2000, 2001, 2002

   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"

#include "gdbtypes.h"

#include "gdbcore.h"

#include "regcache.h"

#include "arch-utils.h"

#include "i386-tdep.h"

#include "i387-tdep.h"

#include "nbsd-tdep.h"

#include "solib-svr4.h"

/* Map a GDB register number to an offset in the reg structure.  */

static int regmap[] =

{

  ( 0 * 4),              /* %eax */

  ( 1 * 4),             /* %ecx */

  ( 2 * 4),             /* %edx */

  ( 3 * 4),             /* %ebx */

  ( 4 * 4),             /* %esp */

  ( 5 * 4),             /* %epb */

  ( 6 * 4),             /* %esi */

  ( 7 * 4),             /* %edi */

  ( 8 * 4),             /* %eip */

  ( 9 * 4),             /* %eflags */

  (10 * 4),             /* %cs */

  (11 * 4),             /* %ss */

  (12 * 4),             /* %ds */

  (13 * 4),             /* %es */

  (14 * 4),             /* %fs */

  (15 * 4),             /* %gs */

};

#define SIZEOF_STRUCT_REG       (16 * 4)

static void

i386nbsd_supply_reg (char *regs, int regno)

{

  int i;

  for (i = 0; i <= 15; i++)

    if (regno == i || regno == -1)

      supply_register (i, regs + regmap[i]);

}

static void

fetch_core_registers (char *core_reg_sect, unsigned core_reg_size, int which,

                      CORE_ADDR ignore)

{

  char *regs, *fsave;

  /* We get everything from one section.  */

  if (which != 0)

    return;

  if (core_reg_size < (SIZEOF_STRUCT_REG + 108))

    {

      warning ("Wrong size register set in core file.");

      return;

    }

  regs = core_reg_sect;

  fsave = core_reg_sect + SIZEOF_STRUCT_REG;

  /* Integer registers.  */

  i386nbsd_supply_reg (regs, -1);

  /* Floating point registers.  */

  i387_supply_fsave (fsave);

}

static void

fetch_elfcore_registers (char *core_reg_sect, unsigned core_reg_size,

                         int which, CORE_ADDR ignore)

{

  switch (which)

    {

    case 0:  /* Integer registers.  */

      if (core_reg_size != SIZEOF_STRUCT_REG)

        warning ("Wrong size register set in core file.");

      else

        i386nbsd_supply_reg (core_reg_sect, -1);

      break;

    case 2:  /* Floating point registers.  */

      if (core_reg_size != 108)

        warning ("Wrong size FP register set in core file.");

      else

        i387_supply_fsave (core_reg_sect);

      break;

    case 3:  /* "Extended" floating point registers.  This is gdb-speak

                for SSE/SSE2. */

      if (core_reg_size != 512)

        warning ("Wrong size XMM register set in core file.");

      else

        i387_supply_fxsave (core_reg_sect);

      break;

    default:

      /* Don't know what kind of register request this is; just ignore it.  */

      break;

    }

}

static struct core_fns i386nbsd_core_fns =

{

  bfd_target_unknown_flavour,           /* core_flavour */

  default_check_format,                 /* check_format */

  default_core_sniffer,                 /* core_sniffer */

  fetch_core_registers,                 /* core_read_registers */

  NULL                                  /* next */

};

static struct core_fns i386nbsd_elfcore_fns =

{

  bfd_target_elf_flavour,               /* core_flavour */

  default_check_format,                 /* check_format */

  default_core_sniffer,                 /* core_sniffer */

  fetch_elfcore_registers,              /* core_read_registers */

  NULL                                  /* next */

};

/* Under NetBSD/i386, signal handler invocations can be identified by the

   designated code sequence that is used to return from a signal handler.

   In particular, the return address of a signal handler points to the

   following code sequence:

        leal    0x10(%esp), %eax

        pushl   %eax

        pushl   %eax

        movl    $0x127, %eax            # __sigreturn14

        int     $0x80

   Each instruction has a unique encoding, so we simply attempt to match

   the instruction the PC is pointing to with any of the above instructions.

   If there is a hit, we know the offset to the start of the designated

   sequence and can then check whether we really are executing in the

   signal trampoline.  If not, -1 is returned, otherwise the offset from the

   start of the return sequence is returned.  */

#define RETCODE_INSN1           0x8d

#define RETCODE_INSN2           0x50

#define RETCODE_INSN3           0x50

#define RETCODE_INSN4           0xb8

#define RETCODE_INSN5           0xcd

#define RETCODE_INSN2_OFF       4

#define RETCODE_INSN3_OFF       5

#define RETCODE_INSN4_OFF       6

#define RETCODE_INSN5_OFF       11

static const unsigned char sigtramp_retcode[] =

{

  RETCODE_INSN1, 0x44, 0x24, 0x10,

  RETCODE_INSN2,

  RETCODE_INSN3,

  RETCODE_INSN4, 0x27, 0x01, 0x00, 0x00,

  RETCODE_INSN5, 0x80,

};

static LONGEST

i386nbsd_sigtramp_offset (CORE_ADDR pc)

{

  unsigned char ret[sizeof(sigtramp_retcode)], insn;

  LONGEST off;

  int i;

  if (read_memory_nobpt (pc, &insn, 1) != 0)

    return -1;

  switch (insn)

    {

    case RETCODE_INSN1:

      off = 0;

      break;

    case RETCODE_INSN2:

      /* INSN2 and INSN3 are the same.  Read at the location of PC+1

         to determine if we're actually looking at INSN2 or INSN3.  */

      if (read_memory_nobpt (pc + 1, &insn, 1) != 0)

        return -1;

      if (insn == RETCODE_INSN3)

        off = RETCODE_INSN2_OFF;

      else

        off = RETCODE_INSN3_OFF;

      break;

    case RETCODE_INSN4:

      off = RETCODE_INSN4_OFF;

      break;

    case RETCODE_INSN5:

      off = RETCODE_INSN5_OFF;

      break;

    default:

      return -1;

    }

  pc -= off;

  if (read_memory_nobpt (pc, (char *) ret, sizeof (ret)) != 0)

    return -1;

  if (memcmp (ret, sigtramp_retcode, sizeof (ret)) == 0)

    return off;

  return -1;

}

static int

i386nbsd_pc_in_sigtramp (CORE_ADDR pc, char *name)

{

  return (nbsd_pc_in_sigtramp (pc, name)

          || i386nbsd_sigtramp_offset (pc) >= 0);

}

/* From <machine/signal.h>.  */

int i386nbsd_sc_pc_offset = 44;

int i386nbsd_sc_sp_offset = 56;

static void

i386nbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)

{

  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);

  /* Obviously NetBSD is BSD-based.  */

  i386bsd_init_abi (info, gdbarch);

  /* NetBSD has different signal trampoline conventions.  */

  set_gdbarch_pc_in_sigtramp (gdbarch, i386nbsd_pc_in_sigtramp);

  /* NetBSD uses -freg-struct-return by default.  */

  tdep->struct_return = reg_struct_return;

  /* NetBSD has a `struct sigcontext' that's different from the

     origional 4.3 BSD.  */

  tdep->sc_pc_offset = i386nbsd_sc_pc_offset;

  tdep->sc_sp_offset = i386nbsd_sc_sp_offset;

}

/* NetBSD ELF.  */

static void

i386nbsdelf_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)

{

  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);

  /* It's still NetBSD.  */

  i386nbsd_init_abi (info, gdbarch);

  /* But ELF-based.  */

  i386_elf_init_abi (info, gdbarch);

  /* NetBSD ELF uses SVR4-style shared libraries.  */

  set_gdbarch_in_solib_call_trampoline (gdbarch,

                                        generic_in_solib_call_trampoline);

  set_solib_svr4_fetch_link_map_offsets (gdbarch,

                                 nbsd_ilp32_solib_svr4_fetch_link_map_offsets);

  /* NetBSD ELF uses -fpcc-struct-return by default.  */

  tdep->struct_return = pcc_struct_return;

  /* We support the SSE registers on NetBSD ELF.  */

  tdep->num_xmm_regs = I386_NUM_XREGS - 1;

  set_gdbarch_num_regs (gdbarch, I386_NUM_GREGS + I386_NUM_FREGS

                        + I386_NUM_XREGS);

}

void

_initialize_i386nbsd_tdep (void)

{

  add_core_fns (&i386nbsd_core_fns);

  add_core_fns (&i386nbsd_elfcore_fns);

  gdbarch_register_osabi (bfd_arch_i386, GDB_OSABI_NETBSD_AOUT,

                          i386nbsd_init_abi);

  gdbarch_register_osabi (bfd_arch_i386, GDB_OSABI_NETBSD_ELF,

                          i386nbsdelf_init_abi);

}