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/* Target-dependent code for NetBSD/Alpha.

   Copyright 2002 Free Software Foundation, Inc.

   Contributed by Wasabi Systems, 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 "gdbcore.h"

#include "frame.h"

#include "regcache.h"

#include "value.h"

#include "solib-svr4.h"

#include "alpha-tdep.h"

#include "alphabsd-tdep.h"

#include "nbsd-tdep.h"

static void

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

                      CORE_ADDR ignore)

{

  char *regs, *fpregs;

  int regno;

  /* Table to map a gdb register number to a trapframe register index.  */

  static const int regmap[] =

  {

     0,   1,   2,   3,

     4,   5,   6,   7,

     8,   9,  10,  11,

    12,  13,  14,  15,

    30,  31,  32,  16,

    17,  18,  19,  20,

    21,  22,  23,  24,

    25,  29,  26

  };

#define SIZEOF_TRAPFRAME (33 * 8)

  /* We get everything from one section.  */

  if (which != 0)

    return;

  regs = core_reg_sect;

  fpregs = core_reg_sect + SIZEOF_TRAPFRAME;

  if (core_reg_size < (SIZEOF_TRAPFRAME + SIZEOF_STRUCT_FPREG))

    {

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

      return;

    }

  /* Integer registers.  */

  for (regno = 0; regno < ALPHA_ZERO_REGNUM; regno++)

    supply_register (regno, regs + (regmap[regno] * 8));

  supply_register (ALPHA_ZERO_REGNUM, NULL);

  supply_register (FP_REGNUM, NULL);

  supply_register (PC_REGNUM, regs + (28 * 8));

  /* Floating point registers.  */

  alphabsd_supply_fpreg (fpregs, -1);

}

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

        alphabsd_supply_reg (core_reg_sect, -1);

      break;

    case 2:  /* Floating point registers.  */

      if (core_reg_size != SIZEOF_STRUCT_FPREG)

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

      else

        alphabsd_supply_fpreg (core_reg_sect, -1);

      break;

    default:

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

      break;

    }

}

static struct core_fns alphanbsd_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 alphanbsd_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/alpha, 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:

        ldq     a0, 0(sp)

        lda     sp, 16(sp)

        lda     v0, 295(zero)   # __sigreturn14

        call_pal callsys

   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.  */

static const unsigned char sigtramp_retcode[] =

{

  0x00, 0x00, 0x1e, 0xa6,       /* ldq a0, 0(sp) */

  0x10, 0x00, 0xde, 0x23,       /* lda sp, 16(sp) */

  0x27, 0x01, 0x1f, 0x20,       /* lda v0, 295(zero) */

  0x83, 0x00, 0x00, 0x00,       /* call_pal callsys */

};

#define RETCODE_NWORDS          4

#define RETCODE_SIZE            (RETCODE_NWORDS * 4)

LONGEST

alphanbsd_sigtramp_offset (CORE_ADDR pc)

{

  unsigned char ret[RETCODE_SIZE], w[4];

  LONGEST off;

  int i;

  if (read_memory_nobpt (pc, (char *) w, 4) != 0)

    return -1;

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

    {

      if (memcmp (w, sigtramp_retcode + (i * 4), 4) == 0)

        break;

    }

  if (i == RETCODE_NWORDS)

    return (-1);

  off = i * 4;

  pc -= off;

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

    return -1;

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

    return off;

  return -1;

}

static int

alphanbsd_pc_in_sigtramp (CORE_ADDR pc, char *func_name)

{

  return (nbsd_pc_in_sigtramp (pc, func_name)

          || alphanbsd_sigtramp_offset (pc) >= 0);

}

static CORE_ADDR

alphanbsd_sigcontext_addr (struct frame_info *frame)

{

  /* FIXME: This is not correct for all versions of NetBSD/alpha.

     We will probably need to disassemble the trampoline to figure

     out which trampoline frame type we have.  */

  return frame->frame;

}

static CORE_ADDR

alphanbsd_skip_sigtramp_frame (struct frame_info *frame, CORE_ADDR pc)

{

  char *name;

  /* FIXME: This is not correct for all versions of NetBSD/alpha.

     We will probably need to disassemble the trampoline to figure

     out which trampoline frame type we have.  */

  find_pc_partial_function (pc, &name, (CORE_ADDR *) NULL, (CORE_ADDR *) NULL);

  if (PC_IN_SIGTRAMP (pc, name))

    return frame->frame;

  return 0;

}

static void

alphanbsd_init_abi (struct gdbarch_info info,

                    struct gdbarch *gdbarch)

{

  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);

  set_gdbarch_pc_in_sigtramp (gdbarch, alphanbsd_pc_in_sigtramp);

  /* NetBSD/alpha does not provide single step support via ptrace(2); we

     must use software single-stepping.  */

  set_gdbarch_software_single_step (gdbarch, alpha_software_single_step);

  set_solib_svr4_fetch_link_map_offsets (gdbarch,

                                 nbsd_lp64_solib_svr4_fetch_link_map_offsets);

  tdep->skip_sigtramp_frame = alphanbsd_skip_sigtramp_frame;

  tdep->dynamic_sigtramp_offset = alphanbsd_sigtramp_offset;

  tdep->sigcontext_addr = alphanbsd_sigcontext_addr;

  tdep->jb_pc = 2;

  tdep->jb_elt_size = 8;

}

void

_initialize_alphanbsd_tdep (void)

{

  gdbarch_register_osabi (bfd_arch_alpha, GDB_OSABI_NETBSD_ELF,

                          alphanbsd_init_abi);

  add_core_fns (&alphanbsd_core_fns);

  add_core_fns (&alphanbsd_elfcore_fns);

}