gas/

[thirdparty/binutils-gdb.git] / gdb / remote.c

/* Remote target communications for serial-line targets in custom GDB protocol

   Copyright (C) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996,
   1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006
   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., 51 Franklin Street, Fifth Floor,
   Boston, MA 02110-1301, USA.  */

/* See the GDB User Guide for details of the GDB remote protocol.  */

#include "defs.h"
#include "gdb_string.h"
#include <ctype.h>
#include <fcntl.h>
#include "inferior.h"
#include "bfd.h"
#include "symfile.h"
#include "exceptions.h"
#include "target.h"
/*#include "terminal.h" */
#include "gdbcmd.h"
#include "objfiles.h"
#include "gdb-stabs.h"
#include "gdbthread.h"
#include "remote.h"
#include "regcache.h"
#include "value.h"
#include "gdb_assert.h"
#include "observer.h"
#include "solib.h"
#include "cli/cli-decode.h"
#include "cli/cli-setshow.h"

#include <ctype.h>
#include <sys/time.h>

#include "event-loop.h"
#include "event-top.h"
#include "inf-loop.h"

#include <signal.h>
#include "serial.h"

#include "gdbcore.h" /* for exec_bfd */

#include "remote-fileio.h"

#include "memory-map.h"

/* The size to align memory write packets, when practical.  The protocol
   does not guarantee any alignment, and gdb will generate short
   writes and unaligned writes, but even as a best-effort attempt this
   can improve bulk transfers.  For instance, if a write is misaligned
   relative to the target's data bus, the stub may need to make an extra
   round trip fetching data from the target.  This doesn't make a
   huge difference, but it's easy to do, so we try to be helpful.

   The alignment chosen is arbitrary; usually data bus width is
   important here, not the possibly larger cache line size.  */
enum { REMOTE_ALIGN_WRITES = 16 };

/* Prototypes for local functions.  */
static void cleanup_sigint_signal_handler (void *dummy);
static void initialize_sigint_signal_handler (void);
static int getpkt_sane (char **buf, long *sizeof_buf, int forever);

static void handle_remote_sigint (int);
static void handle_remote_sigint_twice (int);
static void async_remote_interrupt (gdb_client_data);
void async_remote_interrupt_twice (gdb_client_data);

static void build_remote_gdbarch_data (void);

static void remote_files_info (struct target_ops *ignore);

static void remote_prepare_to_store (void);

static void remote_fetch_registers (int regno);

static void remote_resume (ptid_t ptid, int step,
                           enum target_signal siggnal);
static void remote_async_resume (ptid_t ptid, int step,
				 enum target_signal siggnal);
static void remote_open (char *name, int from_tty);
static void remote_async_open (char *name, int from_tty);

static void extended_remote_open (char *name, int from_tty);
static void extended_remote_async_open (char *name, int from_tty);

static void remote_open_1 (char *, int, struct target_ops *, int extended_p,
			   int async_p);

static void remote_close (int quitting);

static void remote_store_registers (int regno);

static void remote_mourn (void);
static void remote_async_mourn (void);

static void extended_remote_restart (void);

static void extended_remote_mourn (void);

static void remote_mourn_1 (struct target_ops *);

static void remote_send (char **buf, long *sizeof_buf_p);

static int readchar (int timeout);

static ptid_t remote_wait (ptid_t ptid,
                                 struct target_waitstatus *status);
static ptid_t remote_async_wait (ptid_t ptid,
                                       struct target_waitstatus *status);

static void remote_kill (void);
static void remote_async_kill (void);

static int tohex (int nib);

static void remote_detach (char *args, int from_tty);

static void remote_interrupt (int signo);

static void remote_interrupt_twice (int signo);

static void interrupt_query (void);

static void set_thread (int, int);

static int remote_thread_alive (ptid_t);

static void get_offsets (void);

static void skip_frame (void);

static long read_frame (char **buf_p, long *sizeof_buf);

static int hexnumlen (ULONGEST num);

static void init_remote_ops (void);

static void init_extended_remote_ops (void);

static void remote_stop (void);

static int ishex (int ch, int *val);

static int stubhex (int ch);

static int hexnumstr (char *, ULONGEST);

static int hexnumnstr (char *, ULONGEST, int);

static CORE_ADDR remote_address_masked (CORE_ADDR);

static void print_packet (char *);

static unsigned long crc32 (unsigned char *, int, unsigned int);

static void compare_sections_command (char *, int);

static void packet_command (char *, int);

static int stub_unpack_int (char *buff, int fieldlength);

static ptid_t remote_current_thread (ptid_t oldptid);

static void remote_find_new_threads (void);

static void record_currthread (int currthread);

static int fromhex (int a);

static int hex2bin (const char *hex, gdb_byte *bin, int count);

static int bin2hex (const gdb_byte *bin, char *hex, int count);

static int putpkt_binary (char *buf, int cnt);

static void check_binary_download (CORE_ADDR addr);

struct packet_config;

static void show_packet_config_cmd (struct packet_config *config);

static void update_packet_config (struct packet_config *config);

static void set_remote_protocol_packet_cmd (char *args, int from_tty,
					    struct cmd_list_element *c);

static void show_remote_protocol_packet_cmd (struct ui_file *file,
					     int from_tty,
					     struct cmd_list_element *c,
					     const char *value);

void _initialize_remote (void);

/* For "set remote" and "show remote".  */

static struct cmd_list_element *remote_set_cmdlist;
static struct cmd_list_element *remote_show_cmdlist;

/* Description of the remote protocol state for the currently
   connected target.  This is per-target state, and independent of the
   selected architecture.  */

struct remote_state
{
  /* A buffer to use for incoming packets, and its current size.  The
     buffer is grown dynamically for larger incoming packets.
     Outgoing packets may also be constructed in this buffer.
     BUF_SIZE is always at least REMOTE_PACKET_SIZE;
     REMOTE_PACKET_SIZE should be used to limit the length of outgoing
     packets.  */
  char *buf;
  long buf_size;

  /* If we negotiated packet size explicitly (and thus can bypass
     heuristics for the largest packet size that will not overflow
     a buffer in the stub), this will be set to that packet size.
     Otherwise zero, meaning to use the guessed size.  */
  long explicit_packet_size;
};

/* This data could be associated with a target, but we do not always
   have access to the current target when we need it, so for now it is
   static.  This will be fine for as long as only one target is in use
   at a time.  */
static struct remote_state remote_state;

static struct remote_state *
get_remote_state_raw (void)
{
  return &remote_state;
}

/* Description of the remote protocol for a given architecture.  */

struct packet_reg
{
  long offset; /* Offset into G packet.  */
  long regnum; /* GDB's internal register number.  */
  LONGEST pnum; /* Remote protocol register number.  */
  int in_g_packet; /* Always part of G packet.  */
  /* long size in bytes;  == register_size (current_gdbarch, regnum);
     at present.  */
  /* char *name; == REGISTER_NAME (regnum); at present.  */
};

struct remote_arch_state
{
  /* Description of the remote protocol registers.  */
  long sizeof_g_packet;

  /* Description of the remote protocol registers indexed by REGNUM
     (making an array of NUM_REGS + NUM_PSEUDO_REGS in size).  */
  struct packet_reg *regs;

  /* This is the size (in chars) of the first response to the ``g''
     packet.  It is used as a heuristic when determining the maximum
     size of memory-read and memory-write packets.  A target will
     typically only reserve a buffer large enough to hold the ``g''
     packet.  The size does not include packet overhead (headers and
     trailers).  */
  long actual_register_packet_size;

  /* This is the maximum size (in chars) of a non read/write packet.
     It is also used as a cap on the size of read/write packets.  */
  long remote_packet_size;
};


/* Handle for retreving the remote protocol data from gdbarch.  */
static struct gdbarch_data *remote_gdbarch_data_handle;

static struct remote_arch_state *
get_remote_arch_state (void)
{
  return gdbarch_data (current_gdbarch, remote_gdbarch_data_handle);
}

/* Fetch the global remote target state.  */

static struct remote_state *
get_remote_state (void)
{
  /* Make sure that the remote architecture state has been
     initialized, because doing so might reallocate rs->buf.  Any
     function which calls getpkt also needs to be mindful of changes
     to rs->buf, but this call limits the number of places which run
     into trouble.  */
  get_remote_arch_state ();

  return get_remote_state_raw ();
}

static void *
init_remote_state (struct gdbarch *gdbarch)
{
  int regnum;
  struct remote_state *rs = get_remote_state_raw ();
  struct remote_arch_state *rsa;

  rsa = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct remote_arch_state);

  rsa->sizeof_g_packet = 0;

  /* Assume a 1:1 regnum<->pnum table.  */
  rsa->regs = GDBARCH_OBSTACK_CALLOC (gdbarch, NUM_REGS + NUM_PSEUDO_REGS,
				      struct packet_reg);
  for (regnum = 0; regnum < NUM_REGS + NUM_PSEUDO_REGS; regnum++)
    {
      struct packet_reg *r = &rsa->regs[regnum];
      r->pnum = regnum;
      r->regnum = regnum;
      r->offset = DEPRECATED_REGISTER_BYTE (regnum);
      r->in_g_packet = (regnum < NUM_REGS);
      /* ...name = REGISTER_NAME (regnum); */

      /* Compute packet size by accumulating the size of all registers.  */
      if (regnum < NUM_REGS)
	rsa->sizeof_g_packet += register_size (current_gdbarch, regnum);
    }

  /* Default maximum number of characters in a packet body. Many
     remote stubs have a hardwired buffer size of 400 bytes
     (c.f. BUFMAX in m68k-stub.c and i386-stub.c).  BUFMAX-1 is used
     as the maximum packet-size to ensure that the packet and an extra
     NUL character can always fit in the buffer.  This stops GDB
     trashing stubs that try to squeeze an extra NUL into what is
     already a full buffer (As of 1999-12-04 that was most stubs).  */
  rsa->remote_packet_size = 400 - 1;

  /* This one is filled in when a ``g'' packet is received.  */
  rsa->actual_register_packet_size = 0;

  /* Should rsa->sizeof_g_packet needs more space than the
     default, adjust the size accordingly. Remember that each byte is
     encoded as two characters. 32 is the overhead for the packet
     header / footer. NOTE: cagney/1999-10-26: I suspect that 8
     (``$NN:G...#NN'') is a better guess, the below has been padded a
     little.  */
  if (rsa->sizeof_g_packet > ((rsa->remote_packet_size - 32) / 2))
    rsa->remote_packet_size = (rsa->sizeof_g_packet * 2 + 32);

  /* Make sure that the packet buffer is plenty big enough for
     this architecture.  */
  if (rs->buf_size < rsa->remote_packet_size)
    {
      rs->buf_size = 2 * rsa->remote_packet_size;
      rs->buf = xrealloc (rs->buf, rs->buf_size);
    }

  return rsa;
}

/* Return the current allowed size of a remote packet.  This is
   inferred from the current architecture, and should be used to
   limit the length of outgoing packets.  */
static long
get_remote_packet_size (void)
{
  struct remote_state *rs = get_remote_state ();
  struct remote_arch_state *rsa = get_remote_arch_state ();

  if (rs->explicit_packet_size)
    return rs->explicit_packet_size;

  return rsa->remote_packet_size;
}

static struct packet_reg *
packet_reg_from_regnum (struct remote_arch_state *rsa, long regnum)
{
  if (regnum < 0 && regnum >= NUM_REGS + NUM_PSEUDO_REGS)
    return NULL;
  else
    {
      struct packet_reg *r = &rsa->regs[regnum];
      gdb_assert (r->regnum == regnum);
      return r;
    }
}

static struct packet_reg *
packet_reg_from_pnum (struct remote_arch_state *rsa, LONGEST pnum)
{
  int i;
  for (i = 0; i < NUM_REGS + NUM_PSEUDO_REGS; i++)
    {
      struct packet_reg *r = &rsa->regs[i];
      if (r->pnum == pnum)
	return r;
    }
  return NULL;
}

/* FIXME: graces/2002-08-08: These variables should eventually be
   bound to an instance of the target object (as in gdbarch-tdep()),
   when such a thing exists.  */

/* This is set to the data address of the access causing the target
   to stop for a watchpoint.  */
static CORE_ADDR remote_watch_data_address;

/* This is non-zero if target stopped for a watchpoint.  */
static int remote_stopped_by_watchpoint_p;

static struct target_ops remote_ops;

static struct target_ops extended_remote_ops;

/* Temporary target ops. Just like the remote_ops and
   extended_remote_ops, but with asynchronous support.  */
static struct target_ops remote_async_ops;

static struct target_ops extended_async_remote_ops;

/* FIXME: cagney/1999-09-23: Even though getpkt was called with
   ``forever'' still use the normal timeout mechanism.  This is
   currently used by the ASYNC code to guarentee that target reads
   during the initial connect always time-out.  Once getpkt has been
   modified to return a timeout indication and, in turn
   remote_wait()/wait_for_inferior() have gained a timeout parameter
   this can go away.  */
static int wait_forever_enabled_p = 1;


/* This variable chooses whether to send a ^C or a break when the user
   requests program interruption.  Although ^C is usually what remote
   systems expect, and that is the default here, sometimes a break is
   preferable instead.  */

static int remote_break;

/* Descriptor for I/O to remote machine.  Initialize it to NULL so that
   remote_open knows that we don't have a file open when the program
   starts.  */
static struct serial *remote_desc = NULL;

/* This variable sets the number of bits in an address that are to be
   sent in a memory ("M" or "m") packet.  Normally, after stripping
   leading zeros, the entire address would be sent. This variable
   restricts the address to REMOTE_ADDRESS_SIZE bits.  HISTORY: The
   initial implementation of remote.c restricted the address sent in
   memory packets to ``host::sizeof long'' bytes - (typically 32
   bits).  Consequently, for 64 bit targets, the upper 32 bits of an
   address was never sent.  Since fixing this bug may cause a break in
   some remote targets this variable is principly provided to
   facilitate backward compatibility.  */

static int remote_address_size;

/* Tempoary to track who currently owns the terminal.  See
   target_async_terminal_* for more details.  */

static int remote_async_terminal_ours_p;

\f
/* User configurable variables for the number of characters in a
   memory read/write packet.  MIN (rsa->remote_packet_size,
   rsa->sizeof_g_packet) is the default.  Some targets need smaller
   values (fifo overruns, et.al.) and some users need larger values
   (speed up transfers).  The variables ``preferred_*'' (the user
   request), ``current_*'' (what was actually set) and ``forced_*''
   (Positive - a soft limit, negative - a hard limit).  */

struct memory_packet_config
{
  char *name;
  long size;
  int fixed_p;
};

/* Compute the current size of a read/write packet.  Since this makes
   use of ``actual_register_packet_size'' the computation is dynamic.  */

static long
get_memory_packet_size (struct memory_packet_config *config)
{
  struct remote_state *rs = get_remote_state ();
  struct remote_arch_state *rsa = get_remote_arch_state ();

  /* NOTE: The somewhat arbitrary 16k comes from the knowledge (folk
     law?) that some hosts don't cope very well with large alloca()
     calls.  Eventually the alloca() code will be replaced by calls to
     xmalloc() and make_cleanups() allowing this restriction to either
     be lifted or removed.  */
#ifndef MAX_REMOTE_PACKET_SIZE
#define MAX_REMOTE_PACKET_SIZE 16384
#endif
  /* NOTE: 20 ensures we can write at least one byte.  */
#ifndef MIN_REMOTE_PACKET_SIZE
#define MIN_REMOTE_PACKET_SIZE 20
#endif
  long what_they_get;
  if (config->fixed_p)
    {
      if (config->size <= 0)
	what_they_get = MAX_REMOTE_PACKET_SIZE;
      else
	what_they_get = config->size;
    }
  else
    {
      what_they_get = get_remote_packet_size ();
      /* Limit the packet to the size specified by the user.  */
      if (config->size > 0
	  && what_they_get > config->size)
	what_they_get = config->size;

      /* Limit it to the size of the targets ``g'' response unless we have
	 permission from the stub to use a larger packet size.  */
      if (rs->explicit_packet_size == 0
	  && rsa->actual_register_packet_size > 0
	  && what_they_get > rsa->actual_register_packet_size)
	what_they_get = rsa->actual_register_packet_size;
    }
  if (what_they_get > MAX_REMOTE_PACKET_SIZE)
    what_they_get = MAX_REMOTE_PACKET_SIZE;
  if (what_they_get < MIN_REMOTE_PACKET_SIZE)
    what_they_get = MIN_REMOTE_PACKET_SIZE;

  /* Make sure there is room in the global buffer for this packet
     (including its trailing NUL byte).  */
  if (rs->buf_size < what_they_get + 1)
    {
      rs->buf_size = 2 * what_they_get;
      rs->buf = xrealloc (rs->buf, 2 * what_they_get);
    }

  return what_they_get;
}

/* Update the size of a read/write packet. If they user wants
   something really big then do a sanity check.  */

static void
set_memory_packet_size (char *args, struct memory_packet_config *config)
{
  int fixed_p = config->fixed_p;
  long size = config->size;
  if (args == NULL)
    error (_("Argument required (integer, `fixed' or `limited')."));
  else if (strcmp (args, "hard") == 0
      || strcmp (args, "fixed") == 0)
    fixed_p = 1;
  else if (strcmp (args, "soft") == 0
	   || strcmp (args, "limit") == 0)
    fixed_p = 0;
  else
    {
      char *end;
      size = strtoul (args, &end, 0);
      if (args == end)
	error (_("Invalid %s (bad syntax)."), config->name);
#if 0
      /* Instead of explicitly capping the size of a packet to
         MAX_REMOTE_PACKET_SIZE or dissallowing it, the user is
         instead allowed to set the size to something arbitrarily
         large.  */
      if (size > MAX_REMOTE_PACKET_SIZE)
	error (_("Invalid %s (too large)."), config->name);
#endif
    }
  /* Extra checks?  */
  if (fixed_p && !config->fixed_p)
    {
      if (! query (_("The target may not be able to correctly handle a %s\n"
		   "of %ld bytes. Change the packet size? "),
		   config->name, size))
	error (_("Packet size not changed."));
    }
  /* Update the config.  */
  config->fixed_p = fixed_p;
  config->size = size;
}

static void
show_memory_packet_size (struct memory_packet_config *config)
{
  printf_filtered (_("The %s is %ld. "), config->name, config->size);
  if (config->fixed_p)
    printf_filtered (_("Packets are fixed at %ld bytes.\n"),
		     get_memory_packet_size (config));
  else
    printf_filtered (_("Packets are limited to %ld bytes.\n"),
		     get_memory_packet_size (config));
}

static struct memory_packet_config memory_write_packet_config =
{
  "memory-write-packet-size",
};

static void
set_memory_write_packet_size (char *args, int from_tty)
{
  set_memory_packet_size (args, &memory_write_packet_config);
}

static void
show_memory_write_packet_size (char *args, int from_tty)
{
  show_memory_packet_size (&memory_write_packet_config);
}

static long
get_memory_write_packet_size (void)
{
  return get_memory_packet_size (&memory_write_packet_config);
}

static struct memory_packet_config memory_read_packet_config =
{
  "memory-read-packet-size",
};

static void
set_memory_read_packet_size (char *args, int from_tty)
{
  set_memory_packet_size (args, &memory_read_packet_config);
}

static void
show_memory_read_packet_size (char *args, int from_tty)
{
  show_memory_packet_size (&memory_read_packet_config);
}

static long
get_memory_read_packet_size (void)
{
  long size = get_memory_packet_size (&memory_read_packet_config);
  /* FIXME: cagney/1999-11-07: Functions like getpkt() need to get an
     extra buffer size argument before the memory read size can be
     increased beyond this.  */
  if (size > get_remote_packet_size ())
    size = get_remote_packet_size ();
  return size;
}

\f
/* Generic configuration support for packets the stub optionally
   supports. Allows the user to specify the use of the packet as well
   as allowing GDB to auto-detect support in the remote stub.  */

enum packet_support
  {
    PACKET_SUPPORT_UNKNOWN = 0,
    PACKET_ENABLE,
    PACKET_DISABLE
  };

struct packet_config
  {
    const char *name;
    const char *title;
    enum auto_boolean detect;
    enum packet_support support;
  };

/* Analyze a packet's return value and update the packet config
   accordingly.  */

enum packet_result
{
  PACKET_ERROR,
  PACKET_OK,
  PACKET_UNKNOWN
};

static void
update_packet_config (struct packet_config *config)
{
  switch (config->detect)
    {
    case AUTO_BOOLEAN_TRUE:
      config->support = PACKET_ENABLE;
      break;
    case AUTO_BOOLEAN_FALSE:
      config->support = PACKET_DISABLE;
      break;
    case AUTO_BOOLEAN_AUTO:
      config->support = PACKET_SUPPORT_UNKNOWN;
      break;
    }
}

static void
show_packet_config_cmd (struct packet_config *config)
{
  char *support = "internal-error";
  switch (config->support)
    {
    case PACKET_ENABLE:
      support = "enabled";
      break;
    case PACKET_DISABLE:
      support = "disabled";
      break;
    case PACKET_SUPPORT_UNKNOWN:
      support = "unknown";
      break;
    }
  switch (config->detect)
    {
    case AUTO_BOOLEAN_AUTO:
      printf_filtered (_("Support for the `%s' packet is auto-detected, currently %s.\n"),
		       config->name, support);
      break;
    case AUTO_BOOLEAN_TRUE:
    case AUTO_BOOLEAN_FALSE:
      printf_filtered (_("Support for the `%s' packet is currently %s.\n"),
		       config->name, support);
      break;
    }
}

static void
add_packet_config_cmd (struct packet_config *config, const char *name,
		       const char *title, int legacy)
{
  char *set_doc;
  char *show_doc;
  char *cmd_name;

  config->name = name;
  config->title = title;
  config->detect = AUTO_BOOLEAN_AUTO;
  config->support = PACKET_SUPPORT_UNKNOWN;
  set_doc = xstrprintf ("Set use of remote protocol `%s' (%s) packet",
			name, title);
  show_doc = xstrprintf ("Show current use of remote protocol `%s' (%s) packet",
			 name, title);
  /* set/show TITLE-packet {auto,on,off} */
  cmd_name = xstrprintf ("%s-packet", title);
  add_setshow_auto_boolean_cmd (cmd_name, class_obscure,
				&config->detect, set_doc, show_doc, NULL, /* help_doc */
				set_remote_protocol_packet_cmd,
				show_remote_protocol_packet_cmd,
				&remote_set_cmdlist, &remote_show_cmdlist);
  /* set/show remote NAME-packet {auto,on,off} -- legacy.  */
  if (legacy)
    {
      char *legacy_name;
      legacy_name = xstrprintf ("%s-packet", name);
      add_alias_cmd (legacy_name, cmd_name, class_obscure, 0,
		     &remote_set_cmdlist);
      add_alias_cmd (legacy_name, cmd_name, class_obscure, 0,
		     &remote_show_cmdlist);
    }
}

static enum packet_result
packet_check_result (const char *buf)
{
  if (buf[0] != '\0')
    {
      /* The stub recognized the packet request.  Check that the
	 operation succeeded.  */
      if (buf[0] == 'E'
	  && isxdigit (buf[1]) && isxdigit (buf[2])
	  && buf[3] == '\0')
	/* "Enn"  - definitly an error.  */
	return PACKET_ERROR;

      /* Always treat "E." as an error.  This will be used for
	 more verbose error messages, such as E.memtypes.  */
      if (buf[0] == 'E' && buf[1] == '.')
	return PACKET_ERROR;

      /* The packet may or may not be OK.  Just assume it is.  */
      return PACKET_OK;
    }
  else
    /* The stub does not support the packet.  */
    return PACKET_UNKNOWN;
}

static enum packet_result
packet_ok (const char *buf, struct packet_config *config)
{
  enum packet_result result;

  result = packet_check_result (buf);
  switch (result)
    {
    case PACKET_OK:
    case PACKET_ERROR:
      /* The stub recognized the packet request.  */
      switch (config->support)
	{
	case PACKET_SUPPORT_UNKNOWN:
	  if (remote_debug)
	    fprintf_unfiltered (gdb_stdlog,
				    "Packet %s (%s) is supported\n",
				    config->name, config->title);
	  config->support = PACKET_ENABLE;
	  break;
	case PACKET_DISABLE:
	  internal_error (__FILE__, __LINE__,
			  _("packet_ok: attempt to use a disabled packet"));
	  break;
	case PACKET_ENABLE:
	  break;
	}
      break;
    case PACKET_UNKNOWN:
      /* The stub does not support the packet.  */
      switch (config->support)
	{
	case PACKET_ENABLE:
	  if (config->detect == AUTO_BOOLEAN_AUTO)
	    /* If the stub previously indicated that the packet was
	       supported then there is a protocol error..  */
	    error (_("Protocol error: %s (%s) conflicting enabled responses."),
		   config->name, config->title);
	  else
	    /* The user set it wrong.  */
	    error (_("Enabled packet %s (%s) not recognized by stub"),
		   config->name, config->title);
	  break;
	case PACKET_SUPPORT_UNKNOWN:
	  if (remote_debug)
	    fprintf_unfiltered (gdb_stdlog,
				"Packet %s (%s) is NOT supported\n",
				config->name, config->title);
	  config->support = PACKET_DISABLE;
	  break;
	case PACKET_DISABLE:
	  break;
	}
      break;
    }

  return result;
}

enum {
  PACKET_vCont = 0,
  PACKET_X,
  PACKET_qSymbol,
  PACKET_P,
  PACKET_p,
  PACKET_Z0,
  PACKET_Z1,
  PACKET_Z2,
  PACKET_Z3,
  PACKET_Z4,
  PACKET_qXfer_auxv,
  PACKET_qXfer_memory_map,
  PACKET_qGetTLSAddr,
  PACKET_qSupported,
  PACKET_MAX
};

static struct packet_config remote_protocol_packets[PACKET_MAX];

static void
set_remote_protocol_packet_cmd (char *args, int from_tty,
				struct cmd_list_element *c)
{
  struct packet_config *packet;

  for (packet = remote_protocol_packets;
       packet < &remote_protocol_packets[PACKET_MAX];
       packet++)
    {
      if (&packet->detect == c->var)
	{
	  update_packet_config (packet);
	  return;
	}
    }
  internal_error (__FILE__, __LINE__, "Could not find config for %s",
		  c->name);
}

static void
show_remote_protocol_packet_cmd (struct ui_file *file, int from_tty,
				 struct cmd_list_element *c,
				 const char *value)
{
  struct packet_config *packet;

  for (packet = remote_protocol_packets;
       packet < &remote_protocol_packets[PACKET_MAX];
       packet++)
    {
      if (&packet->detect == c->var)
	{
	  show_packet_config_cmd (packet);
	  return;
	}
    }
  internal_error (__FILE__, __LINE__, "Could not find config for %s",
		  c->name);
}

/* Should we try one of the 'Z' requests?  */

enum Z_packet_type
{
  Z_PACKET_SOFTWARE_BP,
  Z_PACKET_HARDWARE_BP,
  Z_PACKET_WRITE_WP,
  Z_PACKET_READ_WP,
  Z_PACKET_ACCESS_WP,
  NR_Z_PACKET_TYPES
};

/* For compatibility with older distributions.  Provide a ``set remote
   Z-packet ...'' command that updates all the Z packet types.  */

static enum auto_boolean remote_Z_packet_detect;

static void
set_remote_protocol_Z_packet_cmd (char *args, int from_tty,
				  struct cmd_list_element *c)
{
  int i;
  for (i = 0; i < NR_Z_PACKET_TYPES; i++)
    {
      remote_protocol_packets[PACKET_Z0 + i].detect = remote_Z_packet_detect;
      update_packet_config (&remote_protocol_packets[PACKET_Z0 + i]);
    }
}

static void
show_remote_protocol_Z_packet_cmd (struct ui_file *file, int from_tty,
				   struct cmd_list_element *c,
				   const char *value)
{
  int i;
  for (i = 0; i < NR_Z_PACKET_TYPES; i++)
    {
      show_packet_config_cmd (&remote_protocol_packets[PACKET_Z0 + i]);
    }
}

/* Should we try the 'ThreadInfo' query packet?

   This variable (NOT available to the user: auto-detect only!)
   determines whether GDB will use the new, simpler "ThreadInfo"
   query or the older, more complex syntax for thread queries.
   This is an auto-detect variable (set to true at each connect,
   and set to false when the target fails to recognize it).  */

static int use_threadinfo_query;
static int use_threadextra_query;

/* Tokens for use by the asynchronous signal handlers for SIGINT.  */
static void *sigint_remote_twice_token;
static void *sigint_remote_token;

/* These are pointers to hook functions that may be set in order to
   modify resume/wait behavior for a particular architecture.  */

void (*deprecated_target_resume_hook) (void);
void (*deprecated_target_wait_loop_hook) (void);
\f


/* These are the threads which we last sent to the remote system.
   -1 for all or -2 for not sent yet.  */
static int general_thread;
static int continue_thread;

/* Call this function as a result of
   1) A halt indication (T packet) containing a thread id
   2) A direct query of currthread
   3) Successful execution of set thread
 */

static void
record_currthread (int currthread)
{
  general_thread = currthread;

  /* If this is a new thread, add it to GDB's thread list.
     If we leave it up to WFI to do this, bad things will happen.  */
  if (!in_thread_list (pid_to_ptid (currthread)))
    {
      add_thread (pid_to_ptid (currthread));
      ui_out_text (uiout, "[New ");
      ui_out_text (uiout, target_pid_to_str (pid_to_ptid (currthread)));
      ui_out_text (uiout, "]\n");
    }
}

#define MAGIC_NULL_PID 42000

static void
set_thread (int th, int gen)
{
  struct remote_state *rs = get_remote_state ();
  char *buf = rs->buf;
  int state = gen ? general_thread : continue_thread;

  if (state == th)
    return;

  buf[0] = 'H';
  buf[1] = gen ? 'g' : 'c';
  if (th == MAGIC_NULL_PID)
    {
      buf[2] = '0';
      buf[3] = '\0';
    }
  else if (th < 0)
    xsnprintf (&buf[2], get_remote_packet_size () - 2, "-%x", -th);
  else
    xsnprintf (&buf[2], get_remote_packet_size () - 2, "%x", th);
  putpkt (buf);
  getpkt (&rs->buf, &rs->buf_size, 0);
  if (gen)
    general_thread = th;
  else
    continue_thread = th;
}
\f
/*  Return nonzero if the thread TH is still alive on the remote system.  */

static int
remote_thread_alive (ptid_t ptid)
{
  struct remote_state *rs = get_remote_state ();
  int tid = PIDGET (ptid);

  if (tid < 0)
    xsnprintf (rs->buf, get_remote_packet_size (), "T-%08x", -tid);
  else
    xsnprintf (rs->buf, get_remote_packet_size (), "T%08x", tid);
  putpkt (rs->buf);
  getpkt (&rs->buf, &rs->buf_size, 0);
  return (rs->buf[0] == 'O' && rs->buf[1] == 'K');
}

/* About these extended threadlist and threadinfo packets.  They are
   variable length packets but, the fields within them are often fixed
   length.  They are redundent enough to send over UDP as is the
   remote protocol in general.  There is a matching unit test module
   in libstub.  */

#define OPAQUETHREADBYTES 8

/* a 64 bit opaque identifier */
typedef unsigned char threadref[OPAQUETHREADBYTES];

/* WARNING: This threadref data structure comes from the remote O.S.,
   libstub protocol encoding, and remote.c. it is not particularly
   changable.  */

/* Right now, the internal structure is int. We want it to be bigger.
   Plan to fix this.
 */

typedef int gdb_threadref;	/* Internal GDB thread reference.  */

/* gdb_ext_thread_info is an internal GDB data structure which is
   equivalent to the reply of the remote threadinfo packet.  */

struct gdb_ext_thread_info
  {
    threadref threadid;		/* External form of thread reference.  */
    int active;			/* Has state interesting to GDB?
				   regs, stack.  */
    char display[256];		/* Brief state display, name,
				   blocked/suspended.  */
    char shortname[32];		/* To be used to name threads.  */
    char more_display[256];	/* Long info, statistics, queue depth,
				   whatever.  */
  };

/* The volume of remote transfers can be limited by submitting
   a mask containing bits specifying the desired information.
   Use a union of these values as the 'selection' parameter to
   get_thread_info. FIXME: Make these TAG names more thread specific.
 */

#define TAG_THREADID 1
#define TAG_EXISTS 2
#define TAG_DISPLAY 4
#define TAG_THREADNAME 8
#define TAG_MOREDISPLAY 16

#define BUF_THREAD_ID_SIZE (OPAQUETHREADBYTES * 2)

char *unpack_varlen_hex (char *buff, ULONGEST *result);

static char *unpack_nibble (char *buf, int *val);

static char *pack_nibble (char *buf, int nibble);

static char *pack_hex_byte (char *pkt, int /* unsigned char */ byte);

static char *unpack_byte (char *buf, int *value);

static char *pack_int (char *buf, int value);

static char *unpack_int (char *buf, int *value);

static char *unpack_string (char *src, char *dest, int length);

static char *pack_threadid (char *pkt, threadref *id);

static char *unpack_threadid (char *inbuf, threadref *id);

void int_to_threadref (threadref *id, int value);

static int threadref_to_int (threadref *ref);

static void copy_threadref (threadref *dest, threadref *src);

static int threadmatch (threadref *dest, threadref *src);

static char *pack_threadinfo_request (char *pkt, int mode,
				      threadref *id);

static int remote_unpack_thread_info_response (char *pkt,
					       threadref *expectedref,
					       struct gdb_ext_thread_info
					       *info);


static int remote_get_threadinfo (threadref *threadid,
				  int fieldset,	/*TAG mask */
				  struct gdb_ext_thread_info *info);

static char *pack_threadlist_request (char *pkt, int startflag,
				      int threadcount,
				      threadref *nextthread);

static int parse_threadlist_response (char *pkt,
				      int result_limit,
				      threadref *original_echo,
				      threadref *resultlist,
				      int *doneflag);

static int remote_get_threadlist (int startflag,
				  threadref *nextthread,
				  int result_limit,
				  int *done,
				  int *result_count,
				  threadref *threadlist);

typedef int (*rmt_thread_action) (threadref *ref, void *context);

static int remote_threadlist_iterator (rmt_thread_action stepfunction,
				       void *context, int looplimit);

static int remote_newthread_step (threadref *ref, void *context);

/* Encode 64 bits in 16 chars of hex.  */

static const char hexchars[] = "0123456789abcdef";

static int
ishex (int ch, int *val)
{
  if ((ch >= 'a') && (ch <= 'f'))
    {
      *val = ch - 'a' + 10;
      return 1;
    }
  if ((ch >= 'A') && (ch <= 'F'))
    {
      *val = ch - 'A' + 10;
      return 1;
    }
  if ((ch >= '0') && (ch <= '9'))
    {
      *val = ch - '0';
      return 1;
    }
  return 0;
}

static int
stubhex (int ch)
{
  if (ch >= 'a' && ch <= 'f')
    return ch - 'a' + 10;
  if (ch >= '0' && ch <= '9')
    return ch - '0';
  if (ch >= 'A' && ch <= 'F')
    return ch - 'A' + 10;
  return -1;
}

static int
stub_unpack_int (char *buff, int fieldlength)
{
  int nibble;
  int retval = 0;

  while (fieldlength)
    {
      nibble = stubhex (*buff++);
      retval |= nibble;
      fieldlength--;
      if (fieldlength)
	retval = retval << 4;
    }
  return retval;
}

char *
unpack_varlen_hex (char *buff,	/* packet to parse */
		   ULONGEST *result)
{
  int nibble;
  ULONGEST retval = 0;

  while (ishex (*buff, &nibble))
    {
      buff++;
      retval = retval << 4;
      retval |= nibble & 0x0f;
    }
  *result = retval;
  return buff;
}

static char *
unpack_nibble (char *buf, int *val)
{
  ishex (*buf++, val);
  return buf;
}

static char *
pack_nibble (char *buf, int nibble)
{
  *buf++ = hexchars[(nibble & 0x0f)];
  return buf;
}

static char *
pack_hex_byte (char *pkt, int byte)
{
  *pkt++ = hexchars[(byte >> 4) & 0xf];
  *pkt++ = hexchars[(byte & 0xf)];
  return pkt;
}

static char *
unpack_byte (char *buf, int *value)
{
  *value = stub_unpack_int (buf, 2);
  return buf + 2;
}

static char *
pack_int (char *buf, int value)
{
  buf = pack_hex_byte (buf, (value >> 24) & 0xff);
  buf = pack_hex_byte (buf, (value >> 16) & 0xff);
  buf = pack_hex_byte (buf, (value >> 8) & 0x0ff);
  buf = pack_hex_byte (buf, (value & 0xff));
  return buf;
}

static char *
unpack_int (char *buf, int *value)
{
  *value = stub_unpack_int (buf, 8);
  return buf + 8;
}

#if 0			/* Currently unused, uncomment when needed.  */
static char *pack_string (char *pkt, char *string);

static char *
pack_string (char *pkt, char *string)
{
  char ch;
  int len;

  len = strlen (string);
  if (len > 200)
    len = 200;		/* Bigger than most GDB packets, junk???  */
  pkt = pack_hex_byte (pkt, len);
  while (len-- > 0)
    {
      ch = *string++;
      if ((ch == '\0') || (ch == '#'))
	ch = '*';		/* Protect encapsulation.  */
      *pkt++ = ch;
    }
  return pkt;
}
#endif /* 0 (unused) */

static char *
unpack_string (char *src, char *dest, int length)
{
  while (length--)
    *dest++ = *src++;
  *dest = '\0';
  return src;
}

static char *
pack_threadid (char *pkt, threadref *id)
{
  char *limit;
  unsigned char *altid;

  altid = (unsigned char *) id;
  limit = pkt + BUF_THREAD_ID_SIZE;
  while (pkt < limit)
    pkt = pack_hex_byte (pkt, *altid++);
  return pkt;
}


static char *
unpack_threadid (char *inbuf, threadref *id)
{
  char *altref;
  char *limit = inbuf + BUF_THREAD_ID_SIZE;
  int x, y;

  altref = (char *) id;

  while (inbuf < limit)
    {
      x = stubhex (*inbuf++);
      y = stubhex (*inbuf++);
      *altref++ = (x << 4) | y;
    }
  return inbuf;
}

/* Externally, threadrefs are 64 bits but internally, they are still
   ints. This is due to a mismatch of specifications.  We would like
   to use 64bit thread references internally.  This is an adapter
   function.  */

void
int_to_threadref (threadref *id, int value)
{
  unsigned char *scan;

  scan = (unsigned char *) id;
  {
    int i = 4;
    while (i--)
      *scan++ = 0;
  }
  *scan++ = (value >> 24) & 0xff;
  *scan++ = (value >> 16) & 0xff;
  *scan++ = (value >> 8) & 0xff;
  *scan++ = (value & 0xff);
}

static int
threadref_to_int (threadref *ref)
{
  int i, value = 0;
  unsigned char *scan;

  scan = *ref;
  scan += 4;
  i = 4;
  while (i-- > 0)
    value = (value << 8) | ((*scan++) & 0xff);
  return value;
}

static void
copy_threadref (threadref *dest, threadref *src)
{
  int i;
  unsigned char *csrc, *cdest;

  csrc = (unsigned char *) src;
  cdest = (unsigned char *) dest;
  i = 8;
  while (i--)
    *cdest++ = *csrc++;
}

static int
threadmatch (threadref *dest, threadref *src)
{
  /* Things are broken right now, so just assume we got a match.  */
#if 0
  unsigned char *srcp, *destp;
  int i, result;
  srcp = (char *) src;
  destp = (char *) dest;

  result = 1;
  while (i-- > 0)
    result &= (*srcp++ == *destp++) ? 1 : 0;
  return result;
#endif
  return 1;
}

/*
   threadid:1,        # always request threadid
   context_exists:2,
   display:4,
   unique_name:8,
   more_display:16
 */

/* Encoding:  'Q':8,'P':8,mask:32,threadid:64 */

static char *
pack_threadinfo_request (char *pkt, int mode, threadref *id)
{
  *pkt++ = 'q';				/* Info Query */
  *pkt++ = 'P';				/* process or thread info */
  pkt = pack_int (pkt, mode);		/* mode */
  pkt = pack_threadid (pkt, id);	/* threadid */
  *pkt = '\0';				/* terminate */
  return pkt;
}

/* These values tag the fields in a thread info response packet.  */
/* Tagging the fields allows us to request specific fields and to
   add more fields as time goes by.  */

#define TAG_THREADID 1		/* Echo the thread identifier.  */
#define TAG_EXISTS 2		/* Is this process defined enough to
				   fetch registers and its stack?  */
#define TAG_DISPLAY 4		/* A short thing maybe to put on a window */
#define TAG_THREADNAME 8	/* string, maps 1-to-1 with a thread is.  */
#define TAG_MOREDISPLAY 16	/* Whatever the kernel wants to say about
				   the process.  */

static int
remote_unpack_thread_info_response (char *pkt, threadref *expectedref,
				    struct gdb_ext_thread_info *info)
{
  struct remote_state *rs = get_remote_state ();
  int mask, length;
  int tag;
  threadref ref;
  char *limit = pkt + rs->buf_size; /* Plausible parsing limit.  */
  int retval = 1;

  /* info->threadid = 0; FIXME: implement zero_threadref.  */
  info->active = 0;
  info->display[0] = '\0';
  info->shortname[0] = '\0';
  info->more_display[0] = '\0';

  /* Assume the characters indicating the packet type have been
     stripped.  */
  pkt = unpack_int (pkt, &mask);	/* arg mask */
  pkt = unpack_threadid (pkt, &ref);

  if (mask == 0)
    warning (_("Incomplete response to threadinfo request."));
  if (!threadmatch (&ref, expectedref))
    {			/* This is an answer to a different request.  */
      warning (_("ERROR RMT Thread info mismatch."));
      return 0;
    }
  copy_threadref (&info->threadid, &ref);

  /* Loop on tagged fields , try to bail if somthing goes wrong.  */

  /* Packets are terminated with nulls.  */
  while ((pkt < limit) && mask && *pkt)
    {
      pkt = unpack_int (pkt, &tag);	/* tag */
      pkt = unpack_byte (pkt, &length);	/* length */
      if (!(tag & mask))		/* Tags out of synch with mask.  */
	{
	  warning (_("ERROR RMT: threadinfo tag mismatch."));
	  retval = 0;
	  break;
	}
      if (tag == TAG_THREADID)
	{
	  if (length != 16)
	    {
	      warning (_("ERROR RMT: length of threadid is not 16."));
	      retval = 0;
	      break;
	    }
	  pkt = unpack_threadid (pkt, &ref);
	  mask = mask & ~TAG_THREADID;
	  continue;
	}
      if (tag == TAG_EXISTS)
	{
	  info->active = stub_unpack_int (pkt, length);
	  pkt += length;
	  mask = mask & ~(TAG_EXISTS);
	  if (length > 8)
	    {
	      warning (_("ERROR RMT: 'exists' length too long."));
	      retval = 0;
	      break;
	    }
	  continue;
	}
      if (tag == TAG_THREADNAME)
	{
	  pkt = unpack_string (pkt, &info->shortname[0], length);
	  mask = mask & ~TAG_THREADNAME;
	  continue;
	}
      if (tag == TAG_DISPLAY)
	{
	  pkt = unpack_string (pkt, &info->display[0], length);
	  mask = mask & ~TAG_DISPLAY;
	  continue;
	}
      if (tag == TAG_MOREDISPLAY)
	{
	  pkt = unpack_string (pkt, &info->more_display[0], length);
	  mask = mask & ~TAG_MOREDISPLAY;
	  continue;
	}
      warning (_("ERROR RMT: unknown thread info tag."));
      break;			/* Not a tag we know about.  */
    }
  return retval;
}

static int
remote_get_threadinfo (threadref *threadid, int fieldset,	/* TAG mask */
		       struct gdb_ext_thread_info *info)
{
  struct remote_state *rs = get_remote_state ();
  int result;

  pack_threadinfo_request (rs->buf, fieldset, threadid);
  putpkt (rs->buf);
  getpkt (&rs->buf, &rs->buf_size, 0);
  result = remote_unpack_thread_info_response (rs->buf + 2,
					       threadid, info);
  return result;
}

/*    Format: i'Q':8,i"L":8,initflag:8,batchsize:16,lastthreadid:32   */

static char *
pack_threadlist_request (char *pkt, int startflag, int threadcount,
			 threadref *nextthread)
{
  *pkt++ = 'q';			/* info query packet */
  *pkt++ = 'L';			/* Process LIST or threadLIST request */
  pkt = pack_nibble (pkt, startflag);		/* initflag 1 bytes */
  pkt = pack_hex_byte (pkt, threadcount);	/* threadcount 2 bytes */
  pkt = pack_threadid (pkt, nextthread);	/* 64 bit thread identifier */
  *pkt = '\0';
  return pkt;
}

/* Encoding:   'q':8,'M':8,count:16,done:8,argthreadid:64,(threadid:64)* */

static int
parse_threadlist_response (char *pkt, int result_limit,
			   threadref *original_echo, threadref *resultlist,
			   int *doneflag)
{
  struct remote_state *rs = get_remote_state ();
  char *limit;
  int count, resultcount, done;

  resultcount = 0;
  /* Assume the 'q' and 'M chars have been stripped.  */
  limit = pkt + (rs->buf_size - BUF_THREAD_ID_SIZE);
  /* done parse past here */
  pkt = unpack_byte (pkt, &count);	/* count field */
  pkt = unpack_nibble (pkt, &done);
  /* The first threadid is the argument threadid.  */
  pkt = unpack_threadid (pkt, original_echo);	/* should match query packet */
  while ((count-- > 0) && (pkt < limit))
    {
      pkt = unpack_threadid (pkt, resultlist++);
      if (resultcount++ >= result_limit)
	break;
    }
  if (doneflag)
    *doneflag = done;
  return resultcount;
}

static int
remote_get_threadlist (int startflag, threadref *nextthread, int result_limit,
		       int *done, int *result_count, threadref *threadlist)
{
  struct remote_state *rs = get_remote_state ();
  static threadref echo_nextthread;
  int result = 1;

  /* Trancate result limit to be smaller than the packet size.  */
  if ((((result_limit + 1) * BUF_THREAD_ID_SIZE) + 10) >= get_remote_packet_size ())
    result_limit = (get_remote_packet_size () / BUF_THREAD_ID_SIZE) - 2;

  pack_threadlist_request (rs->buf, startflag, result_limit, nextthread);
  putpkt (rs->buf);
  getpkt (&rs->buf, &rs->buf_size, 0);

  *result_count =
    parse_threadlist_response (rs->buf + 2, result_limit, &echo_nextthread,
			       threadlist, done);

  if (!threadmatch (&echo_nextthread, nextthread))
    {
      /* FIXME: This is a good reason to drop the packet.  */
      /* Possably, there is a duplicate response.  */
      /* Possabilities :
         retransmit immediatly - race conditions
         retransmit after timeout - yes
         exit
         wait for packet, then exit
       */
      warning (_("HMM: threadlist did not echo arg thread, dropping it."));
      return 0;			/* I choose simply exiting.  */
    }
  if (*result_count <= 0)
    {
      if (*done != 1)
	{
	  warning (_("RMT ERROR : failed to get remote thread list."));
	  result = 0;
	}
      return result;		/* break; */
    }
  if (*result_count > result_limit)
    {
      *result_count = 0;
      warning (_("RMT ERROR: threadlist response longer than requested."));
      return 0;
    }
  return result;
}

/* This is the interface between remote and threads, remotes upper
   interface.  */

/* remote_find_new_threads retrieves the thread list and for each
   thread in the list, looks up the thread in GDB's internal list,
   ading the thread if it does not already exist.  This involves
   getting partial thread lists from the remote target so, polling the
   quit_flag is required.  */


/* About this many threadisds fit in a packet.  */

#define MAXTHREADLISTRESULTS 32

static int
remote_threadlist_iterator (rmt_thread_action stepfunction, void *context,
			    int looplimit)
{
  int done, i, result_count;
  int startflag = 1;
  int result = 1;
  int loopcount = 0;
  static threadref nextthread;
  static threadref resultthreadlist[MAXTHREADLISTRESULTS];

  done = 0;
  while (!done)
    {
      if (loopcount++ > looplimit)
	{
	  result = 0;
	  warning (_("Remote fetch threadlist -infinite loop-."));
	  break;
	}
      if (!remote_get_threadlist (startflag, &nextthread, MAXTHREADLISTRESULTS,
				  &done, &result_count, resultthreadlist))
	{
	  result = 0;
	  break;
	}
      /* Clear for later iterations.  */
      startflag = 0;
      /* Setup to resume next batch of thread references, set nextthread.  */
      if (result_count >= 1)
	copy_threadref (&nextthread, &resultthreadlist[result_count - 1]);
      i = 0;
      while (result_count--)
	if (!(result = (*stepfunction) (&resultthreadlist[i++], context)))
	  break;
    }
  return result;
}

static int
remote_newthread_step (threadref *ref, void *context)
{
  ptid_t ptid;

  ptid = pid_to_ptid (threadref_to_int (ref));

  if (!in_thread_list (ptid))
    add_thread (ptid);
  return 1;			/* continue iterator */
}

#define CRAZY_MAX_THREADS 1000

static ptid_t
remote_current_thread (ptid_t oldpid)
{
  struct remote_state *rs = get_remote_state ();

  putpkt ("qC");
  getpkt (&rs->buf, &rs->buf_size, 0);
  if (rs->buf[0] == 'Q' && rs->buf[1] == 'C')
    /* Use strtoul here, so we'll correctly parse values whose highest
       bit is set.  The protocol carries them as a simple series of
       hex digits; in the absence of a sign, strtol will see such
       values as positive numbers out of range for signed 'long', and
       return LONG_MAX to indicate an overflow.  */
    return pid_to_ptid (strtoul (&rs->buf[2], NULL, 16));
  else
    return oldpid;
}

/* Find new threads for info threads command.
 * Original version, using John Metzler's thread protocol.
 */

static void
remote_find_new_threads (void)
{
  remote_threadlist_iterator (remote_newthread_step, 0,
			      CRAZY_MAX_THREADS);
  if (PIDGET (inferior_ptid) == MAGIC_NULL_PID)	/* ack ack ack */
    inferior_ptid = remote_current_thread (inferior_ptid);
}

/*
 * Find all threads for info threads command.
 * Uses new thread protocol contributed by Cisco.
 * Falls back and attempts to use the older method (above)
 * if the target doesn't respond to the new method.
 */

static void
remote_threads_info (void)
{
  struct remote_state *rs = get_remote_state ();
  char *bufp;
  int tid;

  if (remote_desc == 0)		/* paranoia */
    error (_("Command can only be used when connected to the remote target."));

  if (use_threadinfo_query)
    {
      putpkt ("qfThreadInfo");
      getpkt (&rs->buf, &rs->buf_size, 0);
      bufp = rs->buf;
      if (bufp[0] != '\0')		/* q packet recognized */
	{
	  while (*bufp++ == 'm')	/* reply contains one or more TID */
	    {
	      do
		{
		  /* Use strtoul here, so we'll correctly parse values
		     whose highest bit is set.  The protocol carries
		     them as a simple series of hex digits; in the
		     absence of a sign, strtol will see such values as
		     positive numbers out of range for signed 'long',
		     and return LONG_MAX to indicate an overflow.  */
		  tid = strtoul (bufp, &bufp, 16);
		  if (tid != 0 && !in_thread_list (pid_to_ptid (tid)))
		    add_thread (pid_to_ptid (tid));
		}
	      while (*bufp++ == ',');	/* comma-separated list */
	      putpkt ("qsThreadInfo");
	      getpkt (&rs->buf, &rs->buf_size, 0);
	      bufp = rs->buf;
	    }
	  return;	/* done */
	}
    }

  /* Else fall back to old method based on jmetzler protocol.  */
  use_threadinfo_query = 0;
  remote_find_new_threads ();
  return;
}

/*
 * Collect a descriptive string about the given thread.
 * The target may say anything it wants to about the thread
 * (typically info about its blocked / runnable state, name, etc.).
 * This string will appear in the info threads display.
 *
 * Optional: targets are not required to implement this function.
 */

static char *
remote_threads_extra_info (struct thread_info *tp)
{
  struct remote_state *rs = get_remote_state ();
  int result;
  int set;
  threadref id;
  struct gdb_ext_thread_info threadinfo;
  static char display_buf[100];	/* arbitrary...  */
  int n = 0;                    /* position in display_buf */

  if (remote_desc == 0)		/* paranoia */
    internal_error (__FILE__, __LINE__,
		    _("remote_threads_extra_info"));

  if (use_threadextra_query)
    {
      xsnprintf (rs->buf, get_remote_packet_size (), "qThreadExtraInfo,%x",
		 PIDGET (tp->ptid));
      putpkt (rs->buf);
      getpkt (&rs->buf, &rs->buf_size, 0);
      if (rs->buf[0] != 0)
	{
	  n = min (strlen (rs->buf) / 2, sizeof (display_buf));
	  result = hex2bin (rs->buf, (gdb_byte *) display_buf, n);
	  display_buf [result] = '\0';
	  return display_buf;
	}
    }

  /* If the above query fails, fall back to the old method.  */
  use_threadextra_query = 0;
  set = TAG_THREADID | TAG_EXISTS | TAG_THREADNAME
    | TAG_MOREDISPLAY | TAG_DISPLAY;
  int_to_threadref (&id, PIDGET (tp->ptid));
  if (remote_get_threadinfo (&id, set, &threadinfo))
    if (threadinfo.active)
      {
	if (*threadinfo.shortname)
	  n += xsnprintf (&display_buf[0], sizeof (display_buf) - n,
			  " Name: %s,", threadinfo.shortname);
	if (*threadinfo.display)
	  n += xsnprintf (&display_buf[n], sizeof (display_buf) - n,
			  " State: %s,", threadinfo.display);
	if (*threadinfo.more_display)
	  n += xsnprintf (&display_buf[n], sizeof (display_buf) - n,
			  " Priority: %s", threadinfo.more_display);

	if (n > 0)
	  {
	    /* For purely cosmetic reasons, clear up trailing commas.  */
	    if (',' == display_buf[n-1])
	      display_buf[n-1] = ' ';
	    return display_buf;
	  }
      }
  return NULL;
}
\f

/* Restart the remote side; this is an extended protocol operation.  */

static void
extended_remote_restart (void)
{
  struct remote_state *rs = get_remote_state ();

  /* Send the restart command; for reasons I don't understand the
     remote side really expects a number after the "R".  */
  xsnprintf (rs->buf, get_remote_packet_size (), "R%x", 0);
  putpkt (rs->buf);

  remote_fileio_reset ();

  /* Now query for status so this looks just like we restarted
     gdbserver from scratch.  */
  putpkt ("?");
  getpkt (&rs->buf, &rs->buf_size, 0);
}
\f
/* Clean up connection to a remote debugger.  */

static void
remote_close (int quitting)
{
  if (remote_desc)
    serial_close (remote_desc);
  remote_desc = NULL;
}

/* Query the remote side for the text, data and bss offsets.  */

static void
get_offsets (void)
{
  struct remote_state *rs = get_remote_state ();
  char *buf;
  char *ptr;
  int lose;
  CORE_ADDR text_addr, data_addr, bss_addr;
  struct section_offsets *offs;

  putpkt ("qOffsets");
  getpkt (&rs->buf, &rs->buf_size, 0);
  buf = rs->buf;

  if (buf[0] == '\000')
    return;			/* Return silently.  Stub doesn't support
				   this command.  */
  if (buf[0] == 'E')
    {
      warning (_("Remote failure reply: %s"), buf);
      return;
    }

  /* Pick up each field in turn.  This used to be done with scanf, but
     scanf will make trouble if CORE_ADDR size doesn't match
     conversion directives correctly.  The following code will work
     with any size of CORE_ADDR.  */
  text_addr = data_addr = bss_addr = 0;
  ptr = buf;
  lose = 0;

  if (strncmp (ptr, "Text=", 5) == 0)
    {
      ptr += 5;
      /* Don't use strtol, could lose on big values.  */
      while (*ptr && *ptr != ';')
	text_addr = (text_addr << 4) + fromhex (*ptr++);
    }
  else
    lose = 1;

  if (!lose && strncmp (ptr, ";Data=", 6) == 0)
    {
      ptr += 6;
      while (*ptr && *ptr != ';')
	data_addr = (data_addr << 4) + fromhex (*ptr++);
    }
  else
    lose = 1;

  if (!lose && strncmp (ptr, ";Bss=", 5) == 0)
    {
      ptr += 5;
      while (*ptr && *ptr != ';')
	bss_addr = (bss_addr << 4) + fromhex (*ptr++);
    }
  else
    lose = 1;

  if (lose)
    error (_("Malformed response to offset query, %s"), buf);

  if (symfile_objfile == NULL)
    return;

  offs = ((struct section_offsets *)
	  alloca (SIZEOF_N_SECTION_OFFSETS (symfile_objfile->num_sections)));
  memcpy (offs, symfile_objfile->section_offsets,
	  SIZEOF_N_SECTION_OFFSETS (symfile_objfile->num_sections));

  offs->offsets[SECT_OFF_TEXT (symfile_objfile)] = text_addr;

  /* This is a temporary kludge to force data and bss to use the same offsets
     because that's what nlmconv does now.  The real solution requires changes
     to the stub and remote.c that I don't have time to do right now.  */

  offs->offsets[SECT_OFF_DATA (symfile_objfile)] = data_addr;
  offs->offsets[SECT_OFF_BSS (symfile_objfile)] = data_addr;

  objfile_relocate (symfile_objfile, offs);
}

/* Stub for catch_exception.  */

static void
remote_start_remote (struct ui_out *uiout, void *from_tty_p)
{
  int from_tty = * (int *) from_tty_p;

  immediate_quit++;		/* Allow user to interrupt it.  */

  /* Ack any packet which the remote side has already sent.  */
  serial_write (remote_desc, "+", 1);

  /* Let the stub know that we want it to return the thread.  */
  set_thread (-1, 0);

  inferior_ptid = remote_current_thread (inferior_ptid);

  get_offsets ();		/* Get text, data & bss offsets.  */

  putpkt ("?");			/* Initiate a query from remote machine.  */
  immediate_quit--;

  start_remote (from_tty);	/* Initialize gdb process mechanisms.  */
}

/* Open a connection to a remote debugger.
   NAME is the filename used for communication.  */

static void
remote_open (char *name, int from_tty)
{
  remote_open_1 (name, from_tty, &remote_ops, 0, 0);
}

/* Just like remote_open, but with asynchronous support.  */
static void
remote_async_open (char *name, int from_tty)
{
  remote_open_1 (name, from_tty, &remote_async_ops, 0, 1);
}

/* Open a connection to a remote debugger using the extended
   remote gdb protocol.  NAME is the filename used for communication.  */

static void
extended_remote_open (char *name, int from_tty)
{
  remote_open_1 (name, from_tty, &extended_remote_ops, 1 /*extended_p */,
		 0 /* async_p */);
}

/* Just like extended_remote_open, but with asynchronous support.  */
static void
extended_remote_async_open (char *name, int from_tty)
{
  remote_open_1 (name, from_tty, &extended_async_remote_ops,
		 1 /*extended_p */, 1 /* async_p */);
}

/* Generic code for opening a connection to a remote target.  */

static void
init_all_packet_configs (void)
{
  int i;
  for (i = 0; i < PACKET_MAX; i++)
    update_packet_config (&remote_protocol_packets[i]);
}

/* Symbol look-up.  */

static void
remote_check_symbols (struct objfile *objfile)
{
  struct remote_state *rs = get_remote_state ();
  char *msg, *reply, *tmp;
  struct minimal_symbol *sym;
  int end;

  if (remote_protocol_packets[PACKET_qSymbol].support == PACKET_DISABLE)
    return;

  /* Allocate a message buffer.  We can't reuse the input buffer in RS,
     because we need both at the same time.  */
  msg = alloca (get_remote_packet_size ());

  /* Invite target to request symbol lookups.  */

  putpkt ("qSymbol::");
  getpkt (&rs->buf, &rs->buf_size, 0);
  packet_ok (rs->buf, &remote_protocol_packets[PACKET_qSymbol]);
  reply = rs->buf;

  while (strncmp (reply, "qSymbol:", 8) == 0)
    {
      tmp = &reply[8];
      end = hex2bin (tmp, (gdb_byte *) msg, strlen (tmp) / 2);
      msg[end] = '\0';
      sym = lookup_minimal_symbol (msg, NULL, NULL);
      if (sym == NULL)
	xsnprintf (msg, get_remote_packet_size (), "qSymbol::%s", &reply[8]);
      else
	xsnprintf (msg, get_remote_packet_size (), "qSymbol:%s:%s",
		   paddr_nz (SYMBOL_VALUE_ADDRESS (sym)),
		   &reply[8]);
      putpkt (msg);
      getpkt (&rs->buf, &rs->buf_size, 0);
      reply = rs->buf;
    }
}

static struct serial *
remote_serial_open (char *name)
{
  static int udp_warning = 0;

  /* FIXME: Parsing NAME here is a hack.  But we want to warn here instead
     of in ser-tcp.c, because it is the remote protocol assuming that the
     serial connection is reliable and not the serial connection promising
     to be.  */
  if (!udp_warning && strncmp (name, "udp:", 4) == 0)
    {
      warning (_("\
The remote protocol may be unreliable over UDP.\n\
Some events may be lost, rendering further debugging impossible."));
      udp_warning = 1;
    }

  return serial_open (name);
}

/* This type describes each known response to the qSupported
   packet.  */
struct protocol_feature
{
  /* The name of this protocol feature.  */
  const char *name;

  /* The default for this protocol feature.  */
  enum packet_support default_support;

  /* The function to call when this feature is reported, or after
     qSupported processing if the feature is not supported.
     The first argument points to this structure.  The second
     argument indicates whether the packet requested support be
     enabled, disabled, or probed (or the default, if this function
     is being called at the end of processing and this feature was
     not reported).  The third argument may be NULL; if not NULL, it
     is a NUL-terminated string taken from the packet following
     this feature's name and an equals sign.  */
  void (*func) (const struct protocol_feature *, enum packet_support,
		const char *);

  /* The corresponding packet for this feature.  Only used if
     FUNC is remote_supported_packet.  */
  int packet;
};

static void
remote_supported_packet (const struct protocol_feature *feature,
			 enum packet_support support,
			 const char *argument)
{
  if (argument)
    {
      warning (_("Remote qSupported response supplied an unexpected value for"
		 " \"%s\"."), feature->name);
      return;
    }

  if (remote_protocol_packets[feature->packet].support
      == PACKET_SUPPORT_UNKNOWN)
    remote_protocol_packets[feature->packet].support = support;
}

static void
remote_packet_size (const struct protocol_feature *feature,
		    enum packet_support support, const char *value)
{
  struct remote_state *rs = get_remote_state ();

  int packet_size;
  char *value_end;

  if (support != PACKET_ENABLE)
    return;

  if (value == NULL || *value == '\0')
    {
      warning (_("Remote target reported \"%s\" without a size."),
	       feature->name);
      return;
    }

  errno = 0;
  packet_size = strtol (value, &value_end, 16);
  if (errno != 0 || *value_end != '\0' || packet_size < 0)
    {
      warning (_("Remote target reported \"%s\" with a bad size: \"%s\"."),
	       feature->name, value);
      return;
    }

  if (packet_size > MAX_REMOTE_PACKET_SIZE)
    {
      warning (_("limiting remote suggested packet size (%d bytes) to %d"),
	       packet_size, MAX_REMOTE_PACKET_SIZE);
      packet_size = MAX_REMOTE_PACKET_SIZE;
    }

  /* Record the new maximum packet size.  */
  rs->explicit_packet_size = packet_size;
}

static struct protocol_feature remote_protocol_features[] = {
  { "PacketSize", PACKET_DISABLE, remote_packet_size, -1 },
  { "qXfer:auxv:read", PACKET_DISABLE, remote_supported_packet,
    PACKET_qXfer_auxv },
  { "qXfer:memory-map:read", PACKET_DISABLE, remote_supported_packet,
    PACKET_qXfer_memory_map }
};

static void
remote_query_supported (void)
{
  struct remote_state *rs = get_remote_state ();
  char *next;
  int i;
  unsigned char seen [ARRAY_SIZE (remote_protocol_features)];

  /* The packet support flags are handled differently for this packet
     than for most others.  We treat an error, a disabled packet, and
     an empty response identically: any features which must be reported
     to be used will be automatically disabled.  An empty buffer
     accomplishes this, since that is also the representation for a list
     containing no features.  */

  rs->buf[0] = 0;
  if (remote_protocol_packets[PACKET_qSupported].support != PACKET_DISABLE)
    {
      putpkt ("qSupported");
      getpkt (&rs->buf, &rs->buf_size, 0);

      /* If an error occured, warn, but do not return - just reset the
	 buffer to empty and go on to disable features.  */
      if (packet_ok (rs->buf, &remote_protocol_packets[PACKET_qSupported])
	  == PACKET_ERROR)
	{
	  warning (_("Remote failure reply: %s"), rs->buf);
	  rs->buf[0] = 0;
	}
    }

  memset (seen, 0, sizeof (seen));

  next = rs->buf;
  while (*next)
    {
      enum packet_support is_supported;
      char *p, *end, *name_end, *value;

      /* First separate out this item from the rest of the packet.  If
	 there's another item after this, we overwrite the separator
	 (terminated strings are much easier to work with).  */
      p = next;
      end = strchr (p, ';');
      if (end == NULL)
	{
	  end = p + strlen (p);
	  next = end;
	}
      else
	{
	  if (end == p)
	    {
	      warning (_("empty item in \"qSupported\" response"));
	      continue;
	    }

	  *end = '\0';
	  next = end + 1;
	}

      name_end = strchr (p, '=');
      if (name_end)
	{
	  /* This is a name=value entry.  */
	  is_supported = PACKET_ENABLE;
	  value = name_end + 1;
	  *name_end = '\0';
	}
      else
	{
	  value = NULL;
	  switch (end[-1])
	    {
	    case '+':
	      is_supported = PACKET_ENABLE;
	      break;

	    case '-':
	      is_supported = PACKET_DISABLE;
	      break;

	    case '?':
	      is_supported = PACKET_SUPPORT_UNKNOWN;
	      break;

	    default:
	      warning (_("unrecognized item \"%s\" in \"qSupported\" response"), p);
	      continue;
	    }
	  end[-1] = '\0';
	}

      for (i = 0; i < ARRAY_SIZE (remote_protocol_features); i++)
	if (strcmp (remote_protocol_features[i].name, p) == 0)
	  {
	    const struct protocol_feature *feature;

	    seen[i] = 1;
	    feature = &remote_protocol_features[i];
	    feature->func (feature, is_supported, value);
	    break;
	  }
    }

  /* If we increased the packet size, make sure to increase the global
     buffer size also.  We delay this until after parsing the entire
     qSupported packet, because this is the same buffer we were
     parsing.  */
  if (rs->buf_size < rs->explicit_packet_size)
    {
      rs->buf_size = rs->explicit_packet_size;
      rs->buf = xrealloc (rs->buf, rs->buf_size);
    }

  /* Handle the defaults for unmentioned features.  */
  for (i = 0; i < ARRAY_SIZE (remote_protocol_features); i++)
    if (!seen[i])
      {
	const struct protocol_feature *feature;

	feature = &remote_protocol_features[i];
	feature->func (feature, feature->default_support, NULL);
      }
}


static void
remote_open_1 (char *name, int from_tty, struct target_ops *target,
	       int extended_p, int async_p)
{
  struct remote_state *rs = get_remote_state ();
  if (name == 0)
    error (_("To open a remote debug connection, you need to specify what\n"
	   "serial device is attached to the remote system\n"
	   "(e.g. /dev/ttyS0, /dev/ttya, COM1, etc.)."));

  /* See FIXME above.  */
  if (!async_p)
    wait_forever_enabled_p = 1;

  target_preopen (from_tty);

  unpush_target (target);

  remote_fileio_reset ();
  reopen_exec_file ();
  reread_symbols ();

  remote_desc = remote_serial_open (name);
  if (!remote_desc)
    perror_with_name (name);

  if (baud_rate != -1)
    {
      if (serial_setbaudrate (remote_desc, baud_rate))
	{
	  /* The requested speed could not be set.  Error out to
	     top level after closing remote_desc.  Take care to
	     set remote_desc to NULL to avoid closing remote_desc
	     more than once.  */
	  serial_close (remote_desc);
	  remote_desc = NULL;
	  perror_with_name (name);
	}
    }

  serial_raw (remote_desc);

  /* If there is something sitting in the buffer we might take it as a
     response to a command, which would be bad.  */
  serial_flush_input (remote_desc);

  if (from_tty)
    {
      puts_filtered ("Remote debugging using ");
      puts_filtered (name);
      puts_filtered ("\n");
    }
  push_target (target);		/* Switch to using remote target now.  */

  /* Reset the target state; these things will be queried either by
     remote_query_supported or as they are needed.  */
  init_all_packet_configs ();
  rs->explicit_packet_size = 0;

  general_thread = -2;
  continue_thread = -2;

  /* Probe for ability to use "ThreadInfo" query, as required.  */
  use_threadinfo_query = 1;
  use_threadextra_query = 1;

  /* The first packet we send to the target is the optional "supported
     packets" request.  If the target can answer this, it will tell us
     which later probes to skip.  */
  remote_query_supported ();

  /* Without this, some commands which require an active target (such
     as kill) won't work.  This variable serves (at least) double duty
     as both the pid of the target process (if it has such), and as a
     flag indicating that a target is active.  These functions should
     be split out into seperate variables, especially since GDB will
     someday have a notion of debugging several processes.  */

  inferior_ptid = pid_to_ptid (MAGIC_NULL_PID);

  if (async_p)
    {
      /* With this target we start out by owning the terminal.  */
      remote_async_terminal_ours_p = 1;

      /* FIXME: cagney/1999-09-23: During the initial connection it is
	 assumed that the target is already ready and able to respond to
	 requests. Unfortunately remote_start_remote() eventually calls
	 wait_for_inferior() with no timeout.  wait_forever_enabled_p gets
	 around this. Eventually a mechanism that allows
	 wait_for_inferior() to expect/get timeouts will be
	 implemented.  */
      wait_forever_enabled_p = 0;
    }

  /* First delete any symbols previously loaded from shared libraries.  */
  no_shared_libraries (NULL, 0);

  /* Start the remote connection.  If error() or QUIT, discard this
     target (we'd otherwise be in an inconsistent state) and then
     propogate the error on up the exception chain.  This ensures that
     the caller doesn't stumble along blindly assuming that the
     function succeeded.  The CLI doesn't have this problem but other
     UI's, such as MI do.

     FIXME: cagney/2002-05-19: Instead of re-throwing the exception,
     this function should return an error indication letting the
     caller restore the previous state.  Unfortunately the command
     ``target remote'' is directly wired to this function making that
     impossible.  On a positive note, the CLI side of this problem has
     been fixed - the function set_cmd_context() makes it possible for
     all the ``target ....'' commands to share a common callback
     function.  See cli-dump.c.  */
  {
    struct gdb_exception ex
      = catch_exception (uiout, remote_start_remote, &from_tty,
			 RETURN_MASK_ALL);
    if (ex.reason < 0)
      {
	pop_target ();
	if (async_p)
	  wait_forever_enabled_p = 1;
	throw_exception (ex);
      }
  }

  if (async_p)
    wait_forever_enabled_p = 1;

  if (extended_p)
    {
      /* Tell the remote that we are using the extended protocol.  */
      putpkt ("!");
      getpkt (&rs->buf, &rs->buf_size, 0);
    }

  if (exec_bfd) 	/* No use without an exec file.  */
    remote_check_symbols (symfile_objfile);
}

/* This takes a program previously attached to and detaches it.  After
   this is done, GDB can be used to debug some other program.  We
   better not have left any breakpoints in the target program or it'll
   die when it hits one.  */

static void
remote_detach (char *args, int from_tty)
{
  struct remote_state *rs = get_remote_state ();

  if (args)
    error (_("Argument given to \"detach\" when remotely debugging."));

  /* Tell the remote target to detach.  */
  strcpy (rs->buf, "D");
  remote_send (&rs->buf, &rs->buf_size);

  /* Unregister the file descriptor from the event loop.  */
  if (target_is_async_p ())
    serial_async (remote_desc, NULL, 0);

  target_mourn_inferior ();
  if (from_tty)
    puts_filtered ("Ending remote debugging.\n");
}

/* Same as remote_detach, but don't send the "D" packet; just disconnect.  */

static void
remote_disconnect (struct target_ops *target, char *args, int from_tty)
{
  if (args)
    error (_("Argument given to \"detach\" when remotely debugging."));

  /* Unregister the file descriptor from the event loop.  */
  if (target_is_async_p ())
    serial_async (remote_desc, NULL, 0);

  target_mourn_inferior ();
  if (from_tty)
    puts_filtered ("Ending remote debugging.\n");
}

/* Convert hex digit A to a number.  */

static int
fromhex (int a)
{
  if (a >= '0' && a <= '9')
    return a - '0';
  else if (a >= 'a' && a <= 'f')
    return a - 'a' + 10;
  else if (a >= 'A' && a <= 'F')
    return a - 'A' + 10;
  else
    error (_("Reply contains invalid hex digit %d"), a);
}

static int
hex2bin (const char *hex, gdb_byte *bin, int count)
{
  int i;

  for (i = 0; i < count; i++)
    {
      if (hex[0] == 0 || hex[1] == 0)
	{
	  /* Hex string is short, or of uneven length.
	     Return the count that has been converted so far.  */
	  return i;
	}
      *bin++ = fromhex (hex[0]) * 16 + fromhex (hex[1]);
      hex += 2;
    }
  return i;
}

/* Convert number NIB to a hex digit.  */

static int
tohex (int nib)
{
  if (nib < 10)
    return '0' + nib;
  else
    return 'a' + nib - 10;
}

static int
bin2hex (const gdb_byte *bin, char *hex, int count)
{
  int i;
  /* May use a length, or a nul-terminated string as input.  */
  if (count == 0)
    count = strlen ((char *) bin);

  for (i = 0; i < count; i++)
    {
      *hex++ = tohex ((*bin >> 4) & 0xf);
      *hex++ = tohex (*bin++ & 0xf);
    }
  *hex = 0;
  return i;
}
\f
/* Check for the availability of vCont.  This function should also check
   the response.  */

static void
remote_vcont_probe (struct remote_state *rs)
{
  char *buf;

  strcpy (rs->buf, "vCont?");
  putpkt (rs->buf);
  getpkt (&rs->buf, &rs->buf_size, 0);
  buf = rs->buf;

  /* Make sure that the features we assume are supported.  */
  if (strncmp (buf, "vCont", 5) == 0)
    {
      char *p = &buf[5];
      int support_s, support_S, support_c, support_C;

      support_s = 0;
      support_S = 0;
      support_c = 0;
      support_C = 0;
      while (p && *p == ';')
	{
	  p++;
	  if (*p == 's' && (*(p + 1) == ';' || *(p + 1) == 0))
	    support_s = 1;
	  else if (*p == 'S' && (*(p + 1) == ';' || *(p + 1) == 0))
	    support_S = 1;
	  else if (*p == 'c' && (*(p + 1) == ';' || *(p + 1) == 0))
	    support_c = 1;
	  else if (*p == 'C' && (*(p + 1) == ';' || *(p + 1) == 0))
	    support_C = 1;

	  p = strchr (p, ';');
	}

      /* If s, S, c, and C are not all supported, we can't use vCont.  Clearing
         BUF will make packet_ok disable the packet.  */
      if (!support_s || !support_S || !support_c || !support_C)
	buf[0] = 0;
    }

  packet_ok (buf, &remote_protocol_packets[PACKET_vCont]);
}

/* Resume the remote inferior by using a "vCont" packet.  The thread
   to be resumed is PTID; STEP and SIGGNAL indicate whether the
   resumed thread should be single-stepped and/or signalled.  If PTID's
   PID is -1, then all threads are resumed; the thread to be stepped and/or
   signalled is given in the global INFERIOR_PTID.  This function returns
   non-zero iff it resumes the inferior.

   This function issues a strict subset of all possible vCont commands at the
   moment.  */

static int
remote_vcont_resume (ptid_t ptid, int step, enum target_signal siggnal)
{
  struct remote_state *rs = get_remote_state ();
  int pid = PIDGET (ptid);
  char *buf = NULL, *outbuf;
  struct cleanup *old_cleanup;

  if (remote_protocol_packets[PACKET_vCont].support == PACKET_SUPPORT_UNKNOWN)
    remote_vcont_probe (rs);

  if (remote_protocol_packets[PACKET_vCont].support == PACKET_DISABLE)
    return 0;

  /* If we could generate a wider range of packets, we'd have to worry
     about overflowing BUF.  Should there be a generic
     "multi-part-packet" packet?  */

  if (PIDGET (inferior_ptid) == MAGIC_NULL_PID)
    {
      /* MAGIC_NULL_PTID means that we don't have any active threads, so we
	 don't have any PID numbers the inferior will understand.  Make sure
	 to only send forms that do not specify a PID.  */
      if (step && siggnal != TARGET_SIGNAL_0)
	outbuf = xstrprintf ("vCont;S%02x", siggnal);
      else if (step)
	outbuf = xstrprintf ("vCont;s");
      else if (siggnal != TARGET_SIGNAL_0)
	outbuf = xstrprintf ("vCont;C%02x", siggnal);
      else
	outbuf = xstrprintf ("vCont;c");
    }
  else if (pid == -1)
    {
      /* Resume all threads, with preference for INFERIOR_PTID.  */
      if (step && siggnal != TARGET_SIGNAL_0)
	outbuf = xstrprintf ("vCont;S%02x:%x;c", siggnal,
			     PIDGET (inferior_ptid));
      else if (step)
	outbuf = xstrprintf ("vCont;s:%x;c", PIDGET (inferior_ptid));
      else if (siggnal != TARGET_SIGNAL_0)
	outbuf = xstrprintf ("vCont;C%02x:%x;c", siggnal,
			     PIDGET (inferior_ptid));
      else
	outbuf = xstrprintf ("vCont;c");
    }
  else
    {
      /* Scheduler locking; resume only PTID.  */
      if (step && siggnal != TARGET_SIGNAL_0)
	outbuf = xstrprintf ("vCont;S%02x:%x", siggnal, pid);
      else if (step)
	outbuf = xstrprintf ("vCont;s:%x", pid);
      else if (siggnal != TARGET_SIGNAL_0)
	outbuf = xstrprintf ("vCont;C%02x:%x", siggnal, pid);
      else
	outbuf = xstrprintf ("vCont;c:%x", pid);
    }

  gdb_assert (outbuf && strlen (outbuf) < get_remote_packet_size ());
  old_cleanup = make_cleanup (xfree, outbuf);

  putpkt (outbuf);

  do_cleanups (old_cleanup);

  return 1;
}

/* Tell the remote machine to resume.  */

static enum target_signal last_sent_signal = TARGET_SIGNAL_0;

static int last_sent_step;

static void
remote_resume (ptid_t ptid, int step, enum target_signal siggnal)
{
  struct remote_state *rs = get_remote_state ();
  char *buf;
  int pid = PIDGET (ptid);

  last_sent_signal = siggnal;
  last_sent_step = step;

  /* A hook for when we need to do something at the last moment before
     resumption.  */
  if (deprecated_target_resume_hook)
    (*deprecated_target_resume_hook) ();

  /* The vCont packet doesn't need to specify threads via Hc.  */
  if (remote_vcont_resume (ptid, step, siggnal))
    return;

  /* All other supported resume packets do use Hc, so call set_thread.  */
  if (pid == -1)
    set_thread (0, 0);		/* Run any thread.  */
  else
    set_thread (pid, 0);	/* Run this thread.  */

  buf = rs->buf;
  if (siggnal != TARGET_SIGNAL_0)
    {
      buf[0] = step ? 'S' : 'C';
      buf[1] = tohex (((int) siggnal >> 4) & 0xf);
      buf[2] = tohex (((int) siggnal) & 0xf);
      buf[3] = '\0';
    }
  else
    strcpy (buf, step ? "s" : "c");

  putpkt (buf);
}

/* Same as remote_resume, but with async support.  */
static void
remote_async_resume (ptid_t ptid, int step, enum target_signal siggnal)
{
  remote_resume (ptid, step, siggnal);

  /* We are about to start executing the inferior, let's register it
     with the event loop. NOTE: this is the one place where all the
     execution commands end up. We could alternatively do this in each
     of the execution commands in infcmd.c.  */
  /* FIXME: ezannoni 1999-09-28: We may need to move this out of here
     into infcmd.c in order to allow inferior function calls to work
     NOT asynchronously.  */
  if (target_can_async_p ())
    target_async (inferior_event_handler, 0);
  /* Tell the world that the target is now executing.  */
  /* FIXME: cagney/1999-09-23: Is it the targets responsibility to set
     this?  Instead, should the client of target just assume (for
     async targets) that the target is going to start executing?  Is
     this information already found in the continuation block?  */
  if (target_is_async_p ())
    target_executing = 1;
}
\f

/* Set up the signal handler for SIGINT, while the target is
   executing, ovewriting the 'regular' SIGINT signal handler.  */
static void
initialize_sigint_signal_handler (void)
{
  sigint_remote_token =
    create_async_signal_handler (async_remote_interrupt, NULL);
  signal (SIGINT, handle_remote_sigint);
}

/* Signal handler for SIGINT, while the target is executing.  */
static void
handle_remote_sigint (int sig)
{
  signal (sig, handle_remote_sigint_twice);
  sigint_remote_twice_token =
    create_async_signal_handler (async_remote_interrupt_twice, NULL);
  mark_async_signal_handler_wrapper (sigint_remote_token);
}

/* Signal handler for SIGINT, installed after SIGINT has already been
   sent once.  It will take effect the second time that the user sends
   a ^C.  */
static void
handle_remote_sigint_twice (int sig)
{
  signal (sig, handle_sigint);
  sigint_remote_twice_token =
    create_async_signal_handler (inferior_event_handler_wrapper, NULL);
  mark_async_signal_handler_wrapper (sigint_remote_twice_token);
}

/* Perform the real interruption of the target execution, in response
   to a ^C.  */
static void
async_remote_interrupt (gdb_client_data arg)
{
  if (remote_debug)
    fprintf_unfiltered (gdb_stdlog, "remote_interrupt called\n");

  target_stop ();
}

/* Perform interrupt, if the first attempt did not succeed. Just give
   up on the target alltogether.  */
void
async_remote_interrupt_twice (gdb_client_data arg)
{
  if (remote_debug)
    fprintf_unfiltered (gdb_stdlog, "remote_interrupt_twice called\n");
  /* Do something only if the target was not killed by the previous
     cntl-C.  */
  if (target_executing)
    {
      interrupt_query ();
      signal (SIGINT, handle_remote_sigint);
    }
}

/* Reinstall the usual SIGINT handlers, after the target has
   stopped.  */
static void
cleanup_sigint_signal_handler (void *dummy)
{
  signal (SIGINT, handle_sigint);
  if (sigint_remote_twice_token)
    delete_async_signal_handler ((struct async_signal_handler **)
				 &sigint_remote_twice_token);
  if (sigint_remote_token)
    delete_async_signal_handler ((struct async_signal_handler **)
				 &sigint_remote_token);
}

/* Send ^C to target to halt it.  Target will respond, and send us a
   packet.  */
static void (*ofunc) (int);

/* The command line interface's stop routine. This function is installed
   as a signal handler for SIGINT. The first time a user requests a
   stop, we call remote_stop to send a break or ^C. If there is no
   response from the target (it didn't stop when the user requested it),
   we ask the user if he'd like to detach from the target.  */
static void
remote_interrupt (int signo)
{
  /* If this doesn't work, try more severe steps.  */
  signal (signo, remote_interrupt_twice);

  if (remote_debug)
    fprintf_unfiltered (gdb_stdlog, "remote_interrupt called\n");

  target_stop ();
}

/* The user typed ^C twice.  */

static void
remote_interrupt_twice (int signo)
{
  signal (signo, ofunc);
  interrupt_query ();
  signal (signo, remote_interrupt);
}

/* This is the generic stop called via the target vector. When a target
   interrupt is requested, either by the command line or the GUI, we
   will eventually end up here.  */
static void
remote_stop (void)
{
  /* Send a break or a ^C, depending on user preference.  */
  if (remote_debug)
    fprintf_unfiltered (gdb_stdlog, "remote_stop called\n");

  if (remote_break)
    serial_send_break (remote_desc);
  else
    serial_write (remote_desc, "\003", 1);
}

/* Ask the user what to do when an interrupt is received.  */

static void
interrupt_query (void)
{
  target_terminal_ours ();

  if (query ("Interrupted while waiting for the program.\n\
Give up (and stop debugging it)? "))
    {
      target_mourn_inferior ();
      deprecated_throw_reason (RETURN_QUIT);
    }

  target_terminal_inferior ();
}

/* Enable/disable target terminal ownership.  Most targets can use
   terminal groups to control terminal ownership.  Remote targets are
   different in that explicit transfer of ownership to/from GDB/target
   is required.  */

static void
remote_async_terminal_inferior (void)
{
  /* FIXME: cagney/1999-09-27: Shouldn't need to test for
     sync_execution here.  This function should only be called when
     GDB is resuming the inferior in the forground.  A background
     resume (``run&'') should leave GDB in control of the terminal and
     consequently should not call this code.  */
  if (!sync_execution)
    return;
  /* FIXME: cagney/1999-09-27: Closely related to the above.  Make
     calls target_terminal_*() idenpotent. The event-loop GDB talking
     to an asynchronous target with a synchronous command calls this
     function from both event-top.c and infrun.c/infcmd.c.  Once GDB
     stops trying to transfer the terminal to the target when it
     shouldn't this guard can go away.  */
  if (!remote_async_terminal_ours_p)
    return;
  delete_file_handler (input_fd);
  remote_async_terminal_ours_p = 0;
  initialize_sigint_signal_handler ();
  /* NOTE: At this point we could also register our selves as the
     recipient of all input.  Any characters typed could then be
     passed on down to the target.  */
}

static void
remote_async_terminal_ours (void)
{
  /* See FIXME in remote_async_terminal_inferior.  */
  if (!sync_execution)
    return;
  /* See FIXME in remote_async_terminal_inferior.  */
  if (remote_async_terminal_ours_p)
    return;
  cleanup_sigint_signal_handler (NULL);
  add_file_handler (input_fd, stdin_event_handler, 0);
  remote_async_terminal_ours_p = 1;
}

/* If nonzero, ignore the next kill.  */

int kill_kludge;

void
remote_console_output (char *msg)
{
  char *p;

  for (p = msg; p[0] && p[1]; p += 2)
    {
      char tb[2];
      char c = fromhex (p[0]) * 16 + fromhex (p[1]);
      tb[0] = c;
      tb[1] = 0;
      fputs_unfiltered (tb, gdb_stdtarg);
    }
  gdb_flush (gdb_stdtarg);
}

/* Wait until the remote machine stops, then return,
   storing status in STATUS just as `wait' would.
   Returns "pid", which in the case of a multi-threaded
   remote OS, is the thread-id.  */

static ptid_t
remote_wait (ptid_t ptid, struct target_waitstatus *status)
{
  struct remote_state *rs = get_remote_state ();
  struct remote_arch_state *rsa = get_remote_arch_state ();
  ULONGEST thread_num = -1;
  ULONGEST addr;

  status->kind = TARGET_WAITKIND_EXITED;
  status->value.integer = 0;

  while (1)
    {
      char *buf, *p;

      ofunc = signal (SIGINT, remote_interrupt);
      getpkt (&rs->buf, &rs->buf_size, 1);
      signal (SIGINT, ofunc);

      buf = rs->buf;

      /* This is a hook for when we need to do something (perhaps the
         collection of trace data) every time the target stops.  */
      if (deprecated_target_wait_loop_hook)
	(*deprecated_target_wait_loop_hook) ();

      remote_stopped_by_watchpoint_p = 0;

      switch (buf[0])
	{
	case 'E':		/* Error of some sort.  */
	  warning (_("Remote failure reply: %s"), buf);
	  continue;
	case 'F':		/* File-I/O request.  */
	  remote_fileio_request (buf);
	  continue;
	case 'T':		/* Status with PC, SP, FP, ...  */
	  {
	    gdb_byte regs[MAX_REGISTER_SIZE];

	    /* Expedited reply, containing Signal, {regno, reg} repeat.  */
	    /*  format is:  'Tssn...:r...;n...:r...;n...:r...;#cc', where
	       ss = signal number
	       n... = register number
	       r... = register contents
	     */
	    p = &buf[3];	/* after Txx */

	    while (*p)
	      {
		char *p1;
		char *p_temp;
		int fieldsize;
		LONGEST pnum = 0;

		/* If the packet contains a register number save it in
		   pnum and set p1 to point to the character following
		   it.  Otherwise p1 points to p.  */

		/* If this packet is an awatch packet, don't parse the
		   'a' as a register number.  */

		if (strncmp (p, "awatch", strlen("awatch")) != 0)
		  {
		    /* Read the ``P'' register number.  */
		    pnum = strtol (p, &p_temp, 16);
		    p1 = p_temp;
		  }
		else
		  p1 = p;

		if (p1 == p)	/* No register number present here.  */
		  {
		    p1 = strchr (p, ':');
		    if (p1 == NULL)
		      error (_("Malformed packet(a) (missing colon): %s\n\
Packet: '%s'\n"),
			     p, buf);
		    if (strncmp (p, "thread", p1 - p) == 0)
		      {
			p_temp = unpack_varlen_hex (++p1, &thread_num);
			record_currthread (thread_num);
			p = p_temp;
		      }
		    else if ((strncmp (p, "watch", p1 - p) == 0)
			     || (strncmp (p, "rwatch", p1 - p) == 0)
			     || (strncmp (p, "awatch", p1 - p) == 0))
		      {
			remote_stopped_by_watchpoint_p = 1;
			p = unpack_varlen_hex (++p1, &addr);
			remote_watch_data_address = (CORE_ADDR)addr;
		      }
		    else
 		      {
 			/* Silently skip unknown optional info.  */
 			p_temp = strchr (p1 + 1, ';');
 			if (p_temp)
			  p = p_temp;
 		      }
		  }
		else
		  {
		    struct packet_reg *reg = packet_reg_from_pnum (rsa, pnum);
		    p = p1;

		    if (*p++ != ':')
		      error (_("Malformed packet(b) (missing colon): %s\n\
Packet: '%s'\n"),
			     p, buf);

		    if (reg == NULL)
		      error (_("Remote sent bad register number %s: %s\n\
Packet: '%s'\n"),
			     phex_nz (pnum, 0), p, buf);

		    fieldsize = hex2bin (p, regs,
					 register_size (current_gdbarch,
							reg->regnum));
		    p += 2 * fieldsize;
		    if (fieldsize < register_size (current_gdbarch,
						   reg->regnum))
		      warning (_("Remote reply is too short: %s"), buf);
		    regcache_raw_supply (current_regcache,
					 reg->regnum, regs);
		  }

		if (*p++ != ';')
		  error (_("Remote register badly formatted: %s\nhere: %s"),
			 buf, p);
	      }
	  }
	  /* fall through */
	case 'S':		/* Old style status, just signal only.  */
	  status->kind = TARGET_WAITKIND_STOPPED;
	  status->value.sig = (enum target_signal)
	    (((fromhex (buf[1])) << 4) + (fromhex (buf[2])));

	  if (buf[3] == 'p')
	    {
	      thread_num = strtol ((const char *) &buf[4], NULL, 16);
	      record_currthread (thread_num);
	    }
	  goto got_status;
	case 'W':		/* Target exited.  */
	  {
	    /* The remote process exited.  */
	    status->kind = TARGET_WAITKIND_EXITED;
	    status->value.integer = (fromhex (buf[1]) << 4) + fromhex (buf[2]);
	    goto got_status;
	  }
	case 'X':
	  status->kind = TARGET_WAITKIND_SIGNALLED;
	  status->value.sig = (enum target_signal)
	    (((fromhex (buf[1])) << 4) + (fromhex (buf[2])));
	  kill_kludge = 1;

	  goto got_status;
	case 'O':		/* Console output.  */
	  remote_console_output (buf + 1);
	  continue;
	case '\0':
	  if (last_sent_signal != TARGET_SIGNAL_0)
	    {
	      /* Zero length reply means that we tried 'S' or 'C' and
	         the remote system doesn't support it.  */
	      target_terminal_ours_for_output ();
	      printf_filtered
		("Can't send signals to this remote system.  %s not sent.\n",
		 target_signal_to_name (last_sent_signal));
	      last_sent_signal = TARGET_SIGNAL_0;
	      target_terminal_inferior ();

	      strcpy ((char *) buf, last_sent_step ? "s" : "c");
	      putpkt ((char *) buf);
	      continue;
	    }
	  /* else fallthrough */
	default:
	  warning (_("Invalid remote reply: %s"), buf);
	  continue;
	}
    }
got_status:
  if (thread_num != -1)
    {
      return pid_to_ptid (thread_num);
    }
  return inferior_ptid;
}

/* Async version of remote_wait.  */
static ptid_t
remote_async_wait (ptid_t ptid, struct target_waitstatus *status)
{
  struct remote_state *rs = get_remote_state ();
  struct remote_arch_state *rsa = get_remote_arch_state ();
  ULONGEST thread_num = -1;
  ULONGEST addr;

  status->kind = TARGET_WAITKIND_EXITED;
  status->value.integer = 0;

  remote_stopped_by_watchpoint_p = 0;

  while (1)
    {
      char *buf, *p;

      if (!target_is_async_p ())
	ofunc = signal (SIGINT, remote_interrupt);
      /* FIXME: cagney/1999-09-27: If we're in async mode we should
         _never_ wait for ever -> test on target_is_async_p().
         However, before we do that we need to ensure that the caller
         knows how to take the target into/out of async mode.  */
      getpkt (&rs->buf, &rs->buf_size, wait_forever_enabled_p);
      if (!target_is_async_p ())
	signal (SIGINT, ofunc);

      buf = rs->buf;

      /* This is a hook for when we need to do something (perhaps the
         collection of trace data) every time the target stops.  */
      if (deprecated_target_wait_loop_hook)
	(*deprecated_target_wait_loop_hook) ();

      switch (buf[0])
	{
	case 'E':		/* Error of some sort.  */
	  warning (_("Remote failure reply: %s"), buf);
	  continue;
	case 'F':		/* File-I/O request.  */
	  remote_fileio_request (buf);
	  continue;
	case 'T':		/* Status with PC, SP, FP, ...  */
	  {
	    gdb_byte regs[MAX_REGISTER_SIZE];

	    /* Expedited reply, containing Signal, {regno, reg} repeat.  */
	    /*  format is:  'Tssn...:r...;n...:r...;n...:r...;#cc', where
	       ss = signal number
	       n... = register number
	       r... = register contents
	     */
	    p = &buf[3];	/* after Txx */

	    while (*p)
	      {
		char *p1;
		char *p_temp;
		int fieldsize;
		long pnum = 0;

		/* If the packet contains a register number, save it
		   in pnum and set p1 to point to the character
		   following it.  Otherwise p1 points to p.  */

		/* If this packet is an awatch packet, don't parse the 'a'
		   as a register number.  */

		if (!strncmp (p, "awatch", strlen ("awatch")) != 0)
		  {
		    /* Read the register number.  */
		    pnum = strtol (p, &p_temp, 16);
		    p1 = p_temp;
		  }
		else
		  p1 = p;

		if (p1 == p)	/* No register number present here.  */
		  {
		    p1 = strchr (p, ':');
		    if (p1 == NULL)
		      error (_("Malformed packet(a) (missing colon): %s\n\
Packet: '%s'\n"),
			     p, buf);
		    if (strncmp (p, "thread", p1 - p) == 0)
		      {
			p_temp = unpack_varlen_hex (++p1, &thread_num);
			record_currthread (thread_num);
			p = p_temp;
		      }
		    else if ((strncmp (p, "watch", p1 - p) == 0)
			     || (strncmp (p, "rwatch", p1 - p) == 0)
			     || (strncmp (p, "awatch", p1 - p) == 0))
		      {
			remote_stopped_by_watchpoint_p = 1;
			p = unpack_varlen_hex (++p1, &addr);
			remote_watch_data_address = (CORE_ADDR)addr;
		      }
		    else
 		      {
 			/* Silently skip unknown optional info.  */
 			p_temp = strchr (p1 + 1, ';');
 			if (p_temp)
			  p = p_temp;
 		      }
		  }

		else
		  {
		    struct packet_reg *reg = packet_reg_from_pnum (rsa, pnum);
		    p = p1;
		    if (*p++ != ':')
		      error (_("Malformed packet(b) (missing colon): %s\n\
Packet: '%s'\n"),
			     p, buf);

		    if (reg == NULL)
		      error (_("Remote sent bad register number %ld: %s\n\
Packet: '%s'\n"),
			     pnum, p, buf);

		    fieldsize = hex2bin (p, regs,
					 register_size (current_gdbarch,
							reg->regnum));
		    p += 2 * fieldsize;
		    if (fieldsize < register_size (current_gdbarch,
						   reg->regnum))
		      warning (_("Remote reply is too short: %s"), buf);
		    regcache_raw_supply (current_regcache, reg->regnum, regs);
		  }

		if (*p++ != ';')
		  error (_("Remote register badly formatted: %s\nhere: %s"),
			 buf, p);
	      }
	  }
	  /* fall through */
	case 'S':		/* Old style status, just signal only.  */
	  status->kind = TARGET_WAITKIND_STOPPED;
	  status->value.sig = (enum target_signal)
	    (((fromhex (buf[1])) << 4) + (fromhex (buf[2])));

	  if (buf[3] == 'p')
	    {
	      thread_num = strtol ((const char *) &buf[4], NULL, 16);
	      record_currthread (thread_num);
	    }
	  goto got_status;
	case 'W':		/* Target exited.  */
	  {
	    /* The remote process exited.  */
	    status->kind = TARGET_WAITKIND_EXITED;
	    status->value.integer = (fromhex (buf[1]) << 4) + fromhex (buf[2]);
	    goto got_status;
	  }
	case 'X':
	  status->kind = TARGET_WAITKIND_SIGNALLED;
	  status->value.sig = (enum target_signal)
	    (((fromhex (buf[1])) << 4) + (fromhex (buf[2])));
	  kill_kludge = 1;

	  goto got_status;
	case 'O':		/* Console output.  */
	  remote_console_output (buf + 1);
	  /* Return immediately to the event loop. The event loop will
             still be waiting on the inferior afterwards.  */
          status->kind = TARGET_WAITKIND_IGNORE;
          goto got_status;
	case '\0':
	  if (last_sent_signal != TARGET_SIGNAL_0)
	    {
	      /* Zero length reply means that we tried 'S' or 'C' and
	         the remote system doesn't support it.  */
	      target_terminal_ours_for_output ();
	      printf_filtered
		("Can't send signals to this remote system.  %s not sent.\n",
		 target_signal_to_name (last_sent_signal));
	      last_sent_signal = TARGET_SIGNAL_0;
	      target_terminal_inferior ();

	      strcpy ((char *) buf, last_sent_step ? "s" : "c");
	      putpkt ((char *) buf);
	      continue;
	    }
	  /* else fallthrough */
	default:
	  warning (_("Invalid remote reply: %s"), buf);
	  continue;
	}
    }
got_status:
  if (thread_num != -1)
    {
      return pid_to_ptid (thread_num);
    }
  return inferior_ptid;
}

/* Number of bytes of registers this stub implements.  */

static int register_bytes_found;

/* Read the remote registers into the block REGS.  */
/* Currently we just read all the registers, so we don't use regnum.  */

static int
fetch_register_using_p (int regnum)
{
  struct remote_state *rs = get_remote_state ();
  char *buf, *p;
  char regp[MAX_REGISTER_SIZE];
  int i;

  p = rs->buf;
  *p++ = 'p';
  p += hexnumstr (p, regnum);
  *p++ = '\0';
  remote_send (&rs->buf, &rs->buf_size);

  buf = rs->buf;

  /* If the stub didn't recognize the packet, or if we got an error,
     tell our caller.  */
  if (buf[0] == '\0' || buf[0] == 'E')
    return 0;

  /* If this register is unfetchable, tell the regcache.  */
  if (buf[0] == 'x')
    {
      regcache_raw_supply (current_regcache, regnum, NULL);
      set_register_cached (regnum, -1);
      return 1;
    }

  /* Otherwise, parse and supply the value.  */
  p = buf;
  i = 0;
  while (p[0] != 0)
    {
      if (p[1] == 0)
        {
          error (_("fetch_register_using_p: early buf termination"));
          return 0;
        }

      regp[i++] = fromhex (p[0]) * 16 + fromhex (p[1]);
      p += 2;
    }
  regcache_raw_supply (current_regcache, regnum, regp);
  return 1;
}

static void
remote_fetch_registers (int regnum)
{
  struct remote_state *rs = get_remote_state ();
  struct remote_arch_state *rsa = get_remote_arch_state ();
  char *buf;
  int i;
  char *p;
  char *regs = alloca (rsa->sizeof_g_packet);

  set_thread (PIDGET (inferior_ptid), 1);

  if (regnum >= 0)
    {
      struct packet_reg *reg = packet_reg_from_regnum (rsa, regnum);
      gdb_assert (reg != NULL);
      if (!reg->in_g_packet)
	internal_error (__FILE__, __LINE__,
			_("Attempt to fetch a non G-packet register when this "
			"remote.c does not support the p-packet."));
    }
      switch (remote_protocol_packets[PACKET_p].support)
	{
	case PACKET_DISABLE:
	  break;
	case PACKET_ENABLE:
	  if (fetch_register_using_p (regnum))
	    return;
	  else
	    error (_("Protocol error: p packet not recognized by stub"));
	case PACKET_SUPPORT_UNKNOWN:
	  if (fetch_register_using_p (regnum))
	    {
	      /* The stub recognized the 'p' packet.  Remember this.  */
	      remote_protocol_packets[PACKET_p].support = PACKET_ENABLE;
	      return;
	    }
	  else
	    {
	      /* The stub does not support the 'P' packet.  Use 'G'
	         instead, and don't try using 'P' in the future (it
	         will just waste our time).  */
	      remote_protocol_packets[PACKET_p].support = PACKET_DISABLE;
	      break;
	    }
	}

  sprintf (rs->buf, "g");
  remote_send (&rs->buf, &rs->buf_size);
  buf = rs->buf;

  /* Save the size of the packet sent to us by the target.  Its used
     as a heuristic when determining the max size of packets that the
     target can safely receive.  */
  if ((rsa->actual_register_packet_size) == 0)
    (rsa->actual_register_packet_size) = strlen (buf);

  /* Unimplemented registers read as all bits zero.  */
  memset (regs, 0, rsa->sizeof_g_packet);

  /* We can get out of synch in various cases.  If the first character
     in the buffer is not a hex character, assume that has happened
     and try to fetch another packet to read.  */
  while ((buf[0] < '0' || buf[0] > '9')
	 && (buf[0] < 'A' || buf[0] > 'F')
	 && (buf[0] < 'a' || buf[0] > 'f')
	 && buf[0] != 'x')	/* New: unavailable register value.  */
    {
      if (remote_debug)
	fprintf_unfiltered (gdb_stdlog,
			    "Bad register packet; fetching a new packet\n");
      getpkt (&rs->buf, &rs->buf_size, 0);
      buf = rs->buf;
    }

  /* Reply describes registers byte by byte, each byte encoded as two
     hex characters.  Suck them all up, then supply them to the
     register cacheing/storage mechanism.  */

  p = buf;
  for (i = 0; i < rsa->sizeof_g_packet; i++)
    {
      if (p[0] == 0)
	break;
      if (p[1] == 0)
	{
	  warning (_("Remote reply is of odd length: %s"), buf);
	  /* Don't change register_bytes_found in this case, and don't
	     print a second warning.  */
	  goto supply_them;
	}
      if (p[0] == 'x' && p[1] == 'x')
	regs[i] = 0;		/* 'x' */
      else
	regs[i] = fromhex (p[0]) * 16 + fromhex (p[1]);
      p += 2;
    }

  if (i != register_bytes_found)
    {
      register_bytes_found = i;
      if (REGISTER_BYTES_OK_P ()
	  && !REGISTER_BYTES_OK (i))
	warning (_("Remote reply is wrong length: %s"), buf);
    }

 supply_them:
  {
    int i;
    for (i = 0; i < NUM_REGS + NUM_PSEUDO_REGS; i++)
      {
	struct packet_reg *r = &rsa->regs[i];
	if (r->in_g_packet)
	  {
	    if (r->offset * 2 >= strlen (buf))
	      /* A short packet that didn't include the register's
                 value, this implies that the register is zero (and
                 not that the register is unavailable).  Supply that
                 zero value.  */
	      regcache_raw_supply (current_regcache, r->regnum, NULL);
	    else if (buf[r->offset * 2] == 'x')
	      {
		gdb_assert (r->offset * 2 < strlen (buf));
		/* The register isn't available, mark it as such (at
                   the same time setting the value to zero).  */
		regcache_raw_supply (current_regcache, r->regnum, NULL);
		set_register_cached (i, -1);
	      }
	    else
	      regcache_raw_supply (current_regcache, r->regnum,
				   regs + r->offset);
	  }
      }
  }
}

/* Prepare to store registers.  Since we may send them all (using a
   'G' request), we have to read out the ones we don't want to change
   first.  */

static void
remote_prepare_to_store (void)
{
  struct remote_arch_state *rsa = get_remote_arch_state ();
  int i;
  gdb_byte buf[MAX_REGISTER_SIZE];

  /* Make sure the entire registers array is valid.  */
  switch (remote_protocol_packets[PACKET_P].support)
    {
    case PACKET_DISABLE:
    case PACKET_SUPPORT_UNKNOWN:
      /* Make sure all the necessary registers are cached.  */
      for (i = 0; i < NUM_REGS; i++)
	if (rsa->regs[i].in_g_packet)
	  regcache_raw_read (current_regcache, rsa->regs[i].regnum, buf);
      break;
    case PACKET_ENABLE:
      break;
    }
}

/* Helper: Attempt to store REGNUM using the P packet.  Return fail IFF
   packet was not recognized.  */

static int
store_register_using_P (int regnum)
{
  struct remote_state *rs = get_remote_state ();
  struct remote_arch_state *rsa = get_remote_arch_state ();
  struct packet_reg *reg = packet_reg_from_regnum (rsa, regnum);
  /* Try storing a single register.  */
  char *buf = rs->buf;
  gdb_byte regp[MAX_REGISTER_SIZE];
  char *p;

  xsnprintf (buf, get_remote_packet_size (), "P%s=", phex_nz (reg->pnum, 0));
  p = buf + strlen (buf);
  regcache_raw_collect (current_regcache, reg->regnum, regp);
  bin2hex (regp, p, register_size (current_gdbarch, reg->regnum));
  remote_send (&rs->buf, &rs->buf_size);

  return rs->buf[0] != '\0';
}


/* Store register REGNUM, or all registers if REGNUM == -1, from the
   contents of the register cache buffer.  FIXME: ignores errors.  */

static void
remote_store_registers (int regnum)
{
  struct remote_state *rs = get_remote_state ();
  struct remote_arch_state *rsa = get_remote_arch_state ();
  gdb_byte *regs;
  char *p;

  set_thread (PIDGET (inferior_ptid), 1);

  if (regnum >= 0)
    {
      switch (remote_protocol_packets[PACKET_P].support)
	{
	case PACKET_DISABLE:
	  break;
	case PACKET_ENABLE:
	  if (store_register_using_P (regnum))
	    return;
	  else
	    error (_("Protocol error: P packet not recognized by stub"));
	case PACKET_SUPPORT_UNKNOWN:
	  if (store_register_using_P (regnum))
	    {
	      /* The stub recognized the 'P' packet.  Remember this.  */
	      remote_protocol_packets[PACKET_P].support = PACKET_ENABLE;
	      return;
	    }
	  else
	    {
	      /* The stub does not support the 'P' packet.  Use 'G'
	         instead, and don't try using 'P' in the future (it
	         will just waste our time).  */
	      remote_protocol_packets[PACKET_P].support = PACKET_DISABLE;
	      break;
	    }
	}
    }

  /* Extract all the registers in the regcache copying them into a
     local buffer.  */
  {
    int i;
    regs = alloca (rsa->sizeof_g_packet);
    memset (regs, 0, rsa->sizeof_g_packet);
    for (i = 0; i < NUM_REGS + NUM_PSEUDO_REGS; i++)
      {
	struct packet_reg *r = &rsa->regs[i];
	if (r->in_g_packet)
	  regcache_raw_collect (current_regcache, r->regnum, regs + r->offset);
      }
  }

  /* Command describes registers byte by byte,
     each byte encoded as two hex characters.  */
  p = rs->buf;
  *p++ = 'G';
  /* remote_prepare_to_store insures that register_bytes_found gets set.  */
  bin2hex (regs, p, register_bytes_found);
  remote_send (&rs->buf, &rs->buf_size);
}
\f

/* Return the number of hex digits in num.  */

static int
hexnumlen (ULONGEST num)
{
  int i;

  for (i = 0; num != 0; i++)
    num >>= 4;

  return max (i, 1);
}

/* Set BUF to the minimum number of hex digits representing NUM.  */

static int
hexnumstr (char *buf, ULONGEST num)
{
  int len = hexnumlen (num);
  return hexnumnstr (buf, num, len);
}


/* Set BUF to the hex digits representing NUM, padded to WIDTH characters.  */

static int
hexnumnstr (char *buf, ULONGEST num, int width)
{
  int i;

  buf[width] = '\0';

  for (i = width - 1; i >= 0; i--)
    {
      buf[i] = "0123456789abcdef"[(num & 0xf)];
      num >>= 4;
    }

  return width;
}

/* Mask all but the least significant REMOTE_ADDRESS_SIZE bits.  */

static CORE_ADDR
remote_address_masked (CORE_ADDR addr)
{
  if (remote_address_size > 0
      && remote_address_size < (sizeof (ULONGEST) * 8))
    {
      /* Only create a mask when that mask can safely be constructed
         in a ULONGEST variable.  */
      ULONGEST mask = 1;
      mask = (mask << remote_address_size) - 1;
      addr &= mask;
    }
  return addr;
}

/* Convert BUFFER, binary data at least LEN bytes long, into escaped
   binary data in OUT_BUF.  Set *OUT_LEN to the length of the data
   encoded in OUT_BUF, and return the number of bytes in OUT_BUF
   (which may be more than *OUT_LEN due to escape characters).  The
   total number of bytes in the output buffer will be at most
   OUT_MAXLEN.  */

static int
remote_escape_output (const gdb_byte *buffer, int len,
		      gdb_byte *out_buf, int *out_len,
		      int out_maxlen)
{
  int input_index, output_index;

  output_index = 0;
  for (input_index = 0; input_index < len; input_index++)
    {
      gdb_byte b = buffer[input_index];

      if (b == '$' || b == '#' || b == '}')
	{
	  /* These must be escaped.  */
	  if (output_index + 2 > out_maxlen)
	    break;
	  out_buf[output_index++] = '}';
	  out_buf[output_index++] = b ^ 0x20;
	}
      else
	{
	  if (output_index + 1 > out_maxlen)
	    break;
	  out_buf[output_index++] = b;
	}
    }

  *out_len = input_index;
  return output_index;
}

/* Convert BUFFER, escaped data LEN bytes long, into binary data
   in OUT_BUF.  Return the number of bytes written to OUT_BUF.
   Raise an error if the total number of bytes exceeds OUT_MAXLEN.

   This function reverses remote_escape_output.  It allows more
   escaped characters than that function does, in particular because
   '*' must be escaped to avoid the run-length encoding processing
   in reading packets.  */

static int
remote_unescape_input (const gdb_byte *buffer, int len,
		       gdb_byte *out_buf, int out_maxlen)
{
  int input_index, output_index;
  int escaped;

  output_index = 0;
  escaped = 0;
  for (input_index = 0; input_index < len; input_index++)
    {
      gdb_byte b = buffer[input_index];

      if (output_index + 1 > out_maxlen)
	{
	  warning (_("Received too much data from remote target;"
		     " ignoring overflow."));
	  return output_index;
	}

      if (escaped)
	{
	  out_buf[output_index++] = b ^ 0x20;
	  escaped = 0;
	}
      else if (b == '}')
	escaped = 1;
      else
	out_buf[output_index++] = b;
    }

  if (escaped)
    error (_("Unmatched escape character in target response."));

  return output_index;
}

/* Determine whether the remote target supports binary downloading.
   This is accomplished by sending a no-op memory write of zero length
   to the target at the specified address. It does not suffice to send
   the whole packet, since many stubs strip the eighth bit and
   subsequently compute a wrong checksum, which causes real havoc with
   remote_write_bytes.

   NOTE: This can still lose if the serial line is not eight-bit
   clean. In cases like this, the user should clear "remote
   X-packet".  */

static void
check_binary_download (CORE_ADDR addr)
{
  struct remote_state *rs = get_remote_state ();

  switch (remote_protocol_packets[PACKET_X].support)
    {
    case PACKET_DISABLE:
      break;
    case PACKET_ENABLE:
      break;
    case PACKET_SUPPORT_UNKNOWN:
      {
	char *p;

	p = rs->buf;
	*p++ = 'X';
	p += hexnumstr (p, (ULONGEST) addr);
	*p++ = ',';
	p += hexnumstr (p, (ULONGEST) 0);
	*p++ = ':';
	*p = '\0';

	putpkt_binary (rs->buf, (int) (p - rs->buf));
	getpkt (&rs->buf, &rs->buf_size, 0);

	if (rs->buf[0] == '\0')
	  {
	    if (remote_debug)
	      fprintf_unfiltered (gdb_stdlog,
				  "binary downloading NOT suppported by target\n");
	    remote_protocol_packets[PACKET_X].support = PACKET_DISABLE;
	  }
	else
	  {
	    if (remote_debug)
	      fprintf_unfiltered (gdb_stdlog,
				  "binary downloading suppported by target\n");
	    remote_protocol_packets[PACKET_X].support = PACKET_ENABLE;
	  }
	break;
      }
    }
}

/* Write memory data directly to the remote machine.
   This does not inform the data cache; the data cache uses this.
   HEADER is the starting part of the packet.
   MEMADDR is the address in the remote memory space.
   MYADDR is the address of the buffer in our space.
   LEN is the number of bytes.
   PACKET_FORMAT should be either 'X' or 'M', and indicates if we
   should send data as binary ('X'), or hex-encoded ('M').

   The function creates packet of the form
       <HEADER><ADDRESS>,<LENGTH>:<DATA>

   where encoding of <DATA> is termined by PACKET_FORMAT.

   If USE_LENGTH is 0, then the <LENGTH> field and the preceding comma
   are omitted.

   Returns the number of bytes transferred, or 0 (setting errno) for
   error.  Only transfer a single packet.  */

static int
remote_write_bytes_aux (const char *header, CORE_ADDR memaddr,
			const gdb_byte *myaddr, int len,
			char packet_format, int use_length)
{
  struct remote_state *rs = get_remote_state ();
  char *p;
  char *plen = NULL;
  int plenlen = 0;
  int todo;
  int nr_bytes;
  int payload_size;
  int payload_length;
  int header_length;

  if (packet_format != 'X' && packet_format != 'M')
    internal_error (__FILE__, __LINE__,
		    "remote_write_bytes_aux: bad packet format");

  /* Should this be the selected frame?  */
  gdbarch_remote_translate_xfer_address (current_gdbarch,
					 current_regcache,
					 memaddr, len,
					 &memaddr, &len);

  if (len <= 0)
    return 0;

  payload_size = get_memory_write_packet_size ();

  /* The packet buffer will be large enough for the payload;
     get_memory_packet_size ensures this.  */
  rs->buf[0] = '\0';

  /* Compute the size of the actual payload by subtracting out the
     packet header and footer overhead: "$M<memaddr>,<len>:...#nn".
     */
  payload_size -= strlen ("$,:#NN");
  if (!use_length)
    /* The comma won't be used. */
    payload_size += 1;
  header_length = strlen (header);
  payload_size -= header_length;
  payload_size -= hexnumlen (memaddr);

  /* Construct the packet excluding the data: "<header><memaddr>,<len>:".  */

  strcat (rs->buf, header);
  p = rs->buf + strlen (header);

  /* Compute a best guess of the number of bytes actually transfered.  */
  if (packet_format == 'X')
    {
      /* Best guess at number of bytes that will fit.  */
      todo = min (len, payload_size);
      if (use_length)
	payload_size -= hexnumlen (todo);
      todo = min (todo, payload_size);
    }
  else
    {
      /* Num bytes that will fit.  */
      todo = min (len, payload_size / 2);
      if (use_length)
	payload_size -= hexnumlen (todo);
      todo = min (todo, payload_size / 2);
    }

  if (todo <= 0)
    internal_error (__FILE__, __LINE__,
		    _("minumum packet size too small to write data"));

  /* If we already need another packet, then try to align the end
     of this packet to a useful boundary.  */
  if (todo > 2 * REMOTE_ALIGN_WRITES && todo < len)
    todo = ((memaddr + todo) & ~(REMOTE_ALIGN_WRITES - 1)) - memaddr;

  /* Append "<memaddr>".  */
  memaddr = remote_address_masked (memaddr);
  p += hexnumstr (p, (ULONGEST) memaddr);

  if (use_length)
    {
      /* Append ",".  */
      *p++ = ',';

      /* Append <len>.  Retain the location/size of <len>.  It may need to
	 be adjusted once the packet body has been created.  */
      plen = p;
      plenlen = hexnumstr (p, (ULONGEST) todo);
      p += plenlen;
    }

  /* Append ":".  */
  *p++ = ':';
  *p = '\0';

  /* Append the packet body.  */
  if (packet_format == 'X')
    {
      /* Binary mode.  Send target system values byte by byte, in
	 increasing byte addresses.  Only escape certain critical
	 characters.  */
      payload_length = remote_escape_output (myaddr, todo, p, &nr_bytes,
					     payload_size);

      /* If not all TODO bytes fit, then we'll need another packet.  Make
	 a second try to keep the end of the packet aligned.  Don't do
	 this if the packet is tiny.  */
      if (nr_bytes < todo && nr_bytes > 2 * REMOTE_ALIGN_WRITES)
	{
	  int new_nr_bytes;

	  new_nr_bytes = (((memaddr + nr_bytes) & ~(REMOTE_ALIGN_WRITES - 1))
			  - memaddr);
	  if (new_nr_bytes != nr_bytes)
	    payload_length = remote_escape_output (myaddr, new_nr_bytes,
						   p, &nr_bytes,
						   payload_size);
	}

      p += payload_length;
      if (use_length && nr_bytes < todo)
	{
	  /* Escape chars have filled up the buffer prematurely,
	     and we have actually sent fewer bytes than planned.
	     Fix-up the length field of the packet.  Use the same
	     number of characters as before.  */
	  plen += hexnumnstr (plen, (ULONGEST) nr_bytes, plenlen);
	  *plen = ':';  /* overwrite \0 from hexnumnstr() */
	}
    }
  else
    {
      /* Normal mode: Send target system values byte by byte, in
	 increasing byte addresses.  Each byte is encoded as a two hex
	 value.  */
      nr_bytes = bin2hex (myaddr, p, todo);
      p += 2 * nr_bytes;
    }

  putpkt_binary (rs->buf, (int) (p - rs->buf));
  getpkt (&rs->buf, &rs->buf_size, 0);

  if (rs->buf[0] == 'E')
    {
      /* There is no correspondance between what the remote protocol
	 uses for errors and errno codes.  We would like a cleaner way
	 of representing errors (big enough to include errno codes,
	 bfd_error codes, and others).  But for now just return EIO.  */
      errno = EIO;
      return 0;
    }

  /* Return NR_BYTES, not TODO, in case escape chars caused us to send
     fewer bytes than we'd planned.  */
  return nr_bytes;
}

/* Write memory data directly to the remote machine.
   This does not inform the data cache; the data cache uses this.
   MEMADDR is the address in the remote memory space.
   MYADDR is the address of the buffer in our space.
   LEN is the number of bytes.

   Returns number of bytes transferred, or 0 (setting errno) for
   error.  Only transfer a single packet.  */

int
remote_write_bytes (CORE_ADDR memaddr, const gdb_byte *myaddr, int len)
{
  char *packet_format = 0;

  /* Check whether the target supports binary download.  */
  check_binary_download (memaddr);

  switch (remote_protocol_packets[PACKET_X].support)
    {
    case PACKET_ENABLE:
      packet_format = "X";
      break;
    case PACKET_DISABLE:
      packet_format = "M";
      break;
    case PACKET_SUPPORT_UNKNOWN:
      internal_error (__FILE__, __LINE__,
		      _("remote_write_bytes: bad internal state"));
    default:
      internal_error (__FILE__, __LINE__, _("bad switch"));
    }

  return remote_write_bytes_aux (packet_format,
				 memaddr, myaddr, len, packet_format[0], 1);
}

/* Read memory data directly from the remote machine.
   This does not use the data cache; the data cache uses this.
   MEMADDR is the address in the remote memory space.
   MYADDR is the address of the buffer in our space.
   LEN is the number of bytes.

   Returns number of bytes transferred, or 0 for error.  */

/* NOTE: cagney/1999-10-18: This function (and its siblings in other
   remote targets) shouldn't attempt to read the entire buffer.
   Instead it should read a single packet worth of data and then
   return the byte size of that packet to the caller.  The caller (its
   caller and its callers caller ;-) already contains code for
   handling partial reads.  */

int
remote_read_bytes (CORE_ADDR memaddr, gdb_byte *myaddr, int len)
{
  struct remote_state *rs = get_remote_state ();
  int max_buf_size;		/* Max size of packet output buffer.  */
  int origlen;

  /* Should this be the selected frame?  */
  gdbarch_remote_translate_xfer_address (current_gdbarch,
					 current_regcache,
					 memaddr, len,
					 &memaddr, &len);

  if (len <= 0)
    return 0;

  max_buf_size = get_memory_read_packet_size ();
  /* The packet buffer will be large enough for the payload;
     get_memory_packet_size ensures this.  */

  origlen = len;
  while (len > 0)
    {
      char *p;
      int todo;
      int i;

      todo = min (len, max_buf_size / 2);	/* num bytes that will fit */

      /* construct "m"<memaddr>","<len>" */
      /* sprintf (rs->buf, "m%lx,%x", (unsigned long) memaddr, todo); */
      memaddr = remote_address_masked (memaddr);
      p = rs->buf;
      *p++ = 'm';
      p += hexnumstr (p, (ULONGEST) memaddr);
      *p++ = ',';
      p += hexnumstr (p, (ULONGEST) todo);
      *p = '\0';

      putpkt (rs->buf);
      getpkt (&rs->buf, &rs->buf_size, 0);

      if (rs->buf[0] == 'E'
	  && isxdigit (rs->buf[1]) && isxdigit (rs->buf[2])
	  && rs->buf[3] == '\0')
	{
	  /* There is no correspondance between what the remote
	     protocol uses for errors and errno codes.  We would like
	     a cleaner way of representing errors (big enough to
	     include errno codes, bfd_error codes, and others).  But
	     for now just return EIO.  */
	  errno = EIO;
	  return 0;
	}

      /* Reply describes memory byte by byte,
         each byte encoded as two hex characters.  */

      p = rs->buf;
      if ((i = hex2bin (p, myaddr, todo)) < todo)
	{
	  /* Reply is short.  This means that we were able to read
	     only part of what we wanted to.  */
	  return i + (origlen - len);
	}
      myaddr += todo;
      memaddr += todo;
      len -= todo;
    }
  return origlen;
}
\f
/* Read or write LEN bytes from inferior memory at MEMADDR,
   transferring to or from debugger address BUFFER.  Write to inferior
   if SHOULD_WRITE is nonzero.  Returns length of data written or
   read; 0 for error.  TARGET is unused.  */

static int
remote_xfer_memory (CORE_ADDR mem_addr, gdb_byte *buffer, int mem_len,
		    int should_write, struct mem_attrib *attrib,
		    struct target_ops *target)
{
  int res;

  if (should_write)
    res = remote_write_bytes (mem_addr, buffer, mem_len);
  else
    res = remote_read_bytes (mem_addr, buffer, mem_len);

  return res;
}

/* Sends a packet with content determined by the printf format string
   FORMAT and the remaining arguments, then gets the reply.  Returns
   whether the packet was a success, a failure, or unknown.  */

enum packet_result
remote_send_printf (const char *format, ...)
{
  struct remote_state *rs = get_remote_state ();
  int max_size = get_remote_packet_size ();

  va_list ap;
  va_start (ap, format);

  rs->buf[0] = '\0';
  if (vsnprintf (rs->buf, max_size, format, ap) >= max_size)
    internal_error (__FILE__, __LINE__, "Too long remote packet.");

  if (putpkt (rs->buf) < 0)
    error (_("Communication problem with target."));

  rs->buf[0] = '\0';
  getpkt (&rs->buf, &rs->buf_size, 0);

  return packet_check_result (rs->buf);
}

static void
restore_remote_timeout (void *p)
{
  int value = *(int *)p;
  remote_timeout = value;
}

/* Flash writing can take quite some time.  We'll set
   effectively infinite timeout for flash operations.
   In future, we'll need to decide on a better approach.  */
static const int remote_flash_timeout = 1000;

static void
remote_flash_erase (struct target_ops *ops,
                    ULONGEST address, LONGEST length)
{
  int saved_remote_timeout = remote_timeout;
  enum packet_result ret;

  struct cleanup *back_to = make_cleanup (restore_remote_timeout,
                                          &saved_remote_timeout);
  remote_timeout = remote_flash_timeout;

  ret = remote_send_printf ("vFlashErase:%s,%s",
			    paddr (address),
			    phex (length, 4));
  switch (ret)
    {
    case PACKET_UNKNOWN:
      error (_("Remote target does not support flash erase"));
    case PACKET_ERROR:
      error (_("Error erasing flash with vFlashErase packet"));
    default:
      break;
    }

  do_cleanups (back_to);
}

static LONGEST
remote_flash_write (struct target_ops *ops,
                    ULONGEST address, LONGEST length,
                    const gdb_byte *data)
{
  int saved_remote_timeout = remote_timeout;
  int ret;
  struct cleanup *back_to = make_cleanup (restore_remote_timeout,
                                          &saved_remote_timeout);

  remote_timeout = remote_flash_timeout;
  ret = remote_write_bytes_aux ("vFlashWrite:", address, data, length, 'X', 0);
  do_cleanups (back_to);

  return ret;
}

static void
remote_flash_done (struct target_ops *ops)
{
  int saved_remote_timeout = remote_timeout;
  int ret;
  struct cleanup *back_to = make_cleanup (restore_remote_timeout,
                                          &saved_remote_timeout);

  remote_timeout = remote_flash_timeout;
  ret = remote_send_printf ("vFlashDone");
  do_cleanups (back_to);

  switch (ret)
    {
    case PACKET_UNKNOWN:
      error (_("Remote target does not support vFlashDone"));
    case PACKET_ERROR:
      error (_("Error finishing flash operation"));
    default:
      break;
    }
}

static void
remote_files_info (struct target_ops *ignore)
{
  puts_filtered ("Debugging a target over a serial line.\n");
}
\f
/* Stuff for dealing with the packets which are part of this protocol.
   See comment at top of file for details.  */

/* Read a single character from the remote end.  */

static int
readchar (int timeout)
{
  int ch;

  ch = serial_readchar (remote_desc, timeout);

  if (ch >= 0)
    return ch;

  switch ((enum serial_rc) ch)
    {
    case SERIAL_EOF:
      target_mourn_inferior ();
      error (_("Remote connection closed"));
      /* no return */
    case SERIAL_ERROR:
      perror_with_name (_("Remote communication error"));
      /* no return */
    case SERIAL_TIMEOUT:
      break;
    }
  return ch;
}

/* Send the command in *BUF to the remote machine, and read the reply
   into *BUF.  Report an error if we get an error reply.  Resize
   *BUF using xrealloc if necessary to hold the result, and update
   *SIZEOF_BUF.  */

static void
remote_send (char **buf,
	     long *sizeof_buf)
{
  putpkt (*buf);
  getpkt (buf, sizeof_buf, 0);

  if ((*buf)[0] == 'E')
    error (_("Remote failure reply: %s"), *buf);
}

/* Display a null-terminated packet on stdout, for debugging, using C
   string notation.  */

static void
print_packet (char *buf)
{
  puts_filtered ("\"");
  fputstr_filtered (buf, '"', gdb_stdout);
  puts_filtered ("\"");
}

int
putpkt (char *buf)
{
  return putpkt_binary (buf, strlen (buf));
}

/* Send a packet to the remote machine, with error checking.  The data
   of the packet is in BUF.  The string in BUF can be at most
   get_remote_packet_size () - 5 to account for the $, # and checksum,
   and for a possible /0 if we are debugging (remote_debug) and want
   to print the sent packet as a string.  */

static int
putpkt_binary (char *buf, int cnt)
{
  int i;
  unsigned char csum = 0;
  char *buf2 = alloca (cnt + 6);

  int ch;
  int tcount = 0;
  char *p;

  /* Copy the packet into buffer BUF2, encapsulating it
     and giving it a checksum.  */

  p = buf2;
  *p++ = '$';

  for (i = 0; i < cnt; i++)
    {
      csum += buf[i];
      *p++ = buf[i];
    }
  *p++ = '#';
  *p++ = tohex ((csum >> 4) & 0xf);
  *p++ = tohex (csum & 0xf);

  /* Send it over and over until we get a positive ack.  */

  while (1)
    {
      int started_error_output = 0;

      if (remote_debug)
	{
	  *p = '\0';
	  fprintf_unfiltered (gdb_stdlog, "Sending packet: ");
	  fputstrn_unfiltered (buf2, p - buf2, 0, gdb_stdlog);
	  fprintf_unfiltered (gdb_stdlog, "...");
	  gdb_flush (gdb_stdlog);
	}
      if (serial_write (remote_desc, buf2, p - buf2))
	perror_with_name (_("putpkt: write failed"));

      /* Read until either a timeout occurs (-2) or '+' is read.  */
      while (1)
	{
	  ch = readchar (remote_timeout);

	  if (remote_debug)
	    {
	      switch (ch)
		{
		case '+':
		case '-':
		case SERIAL_TIMEOUT:
		case '$':
		  if (started_error_output)
		    {
		      putchar_unfiltered ('\n');
		      started_error_output = 0;
		    }
		}
	    }

	  switch (ch)
	    {
	    case '+':
	      if (remote_debug)
		fprintf_unfiltered (gdb_stdlog, "Ack\n");
	      return 1;
	    case '-':
	      if (remote_debug)
		fprintf_unfiltered (gdb_stdlog, "Nak\n");
	    case SERIAL_TIMEOUT:
	      tcount++;
	      if (tcount > 3)
		return 0;
	      break;		/* Retransmit buffer.  */
	    case '$':
	      {
	        if (remote_debug)
		  fprintf_unfiltered (gdb_stdlog,
				      "Packet instead of Ack, ignoring it\n");
		/* It's probably an old response sent because an ACK
		   was lost.  Gobble up the packet and ack it so it
		   doesn't get retransmitted when we resend this
		   packet.  */
		skip_frame ();
		serial_write (remote_desc, "+", 1);
		continue;	/* Now, go look for +.  */
	      }
	    default:
	      if (remote_debug)
		{
		  if (!started_error_output)
		    {
		      started_error_output = 1;
		      fprintf_unfiltered (gdb_stdlog, "putpkt: Junk: ");
		    }
		  fputc_unfiltered (ch & 0177, gdb_stdlog);
		}
	      continue;
	    }
	  break;		/* Here to retransmit.  */
	}

#if 0
      /* This is wrong.  If doing a long backtrace, the user should be
         able to get out next time we call QUIT, without anything as
         violent as interrupt_query.  If we want to provide a way out of
         here without getting to the next QUIT, it should be based on
         hitting ^C twice as in remote_wait.  */
      if (quit_flag)
	{
	  quit_flag = 0;
	  interrupt_query ();
	}
#endif
    }
}

/* Come here after finding the start of a frame when we expected an
   ack.  Do our best to discard the rest of this packet.  */

static void
skip_frame (void)
{
  int c;

  while (1)
    {
      c = readchar (remote_timeout);
      switch (c)
	{
	case SERIAL_TIMEOUT:
	  /* Nothing we can do.  */
	  return;
	case '#':
	  /* Discard the two bytes of checksum and stop.  */
	  c = readchar (remote_timeout);
	  if (c >= 0)
	    c = readchar (remote_timeout);

	  return;
	case '*':		/* Run length encoding.  */
	  /* Discard the repeat count.  */
	  c = readchar (remote_timeout);
	  if (c < 0)
	    return;
	  break;
	default:
	  /* A regular character.  */
	  break;
	}
    }
}

/* Come here after finding the start of the frame.  Collect the rest
   into *BUF, verifying the checksum, length, and handling run-length
   compression.  NUL terminate the buffer.  If there is not enough room,
   expand *BUF using xrealloc.

   Returns -1 on error, number of characters in buffer (ignoring the
   trailing NULL) on success. (could be extended to return one of the
   SERIAL status indications).  */

static long
read_frame (char **buf_p,
	    long *sizeof_buf)
{
  unsigned char csum;
  long bc;
  int c;
  char *buf = *buf_p;

  csum = 0;
  bc = 0;

  while (1)
    {
      c = readchar (remote_timeout);
      switch (c)
	{
	case SERIAL_TIMEOUT:
	  if (remote_debug)
	    fputs_filtered ("Timeout in mid-packet, retrying\n", gdb_stdlog);
	  return -1;
	case '$':
	  if (remote_debug)
	    fputs_filtered ("Saw new packet start in middle of old one\n",
			    gdb_stdlog);
	  return -1;		/* Start a new packet, count retries.  */
	case '#':
	  {
	    unsigned char pktcsum;
	    int check_0 = 0;
	    int check_1 = 0;

	    buf[bc] = '\0';

	    check_0 = readchar (remote_timeout);
	    if (check_0 >= 0)
	      check_1 = readchar (remote_timeout);

	    if (check_0 == SERIAL_TIMEOUT || check_1 == SERIAL_TIMEOUT)
	      {
		if (remote_debug)
		  fputs_filtered ("Timeout in checksum, retrying\n",
				  gdb_stdlog);
		return -1;
	      }
	    else if (check_0 < 0 || check_1 < 0)
	      {
		if (remote_debug)
		  fputs_filtered ("Communication error in checksum\n",
				  gdb_stdlog);
		return -1;
	      }

	    pktcsum = (fromhex (check_0) << 4) | fromhex (check_1);
	    if (csum == pktcsum)
              return bc;

	    if (remote_debug)
	      {
		fprintf_filtered (gdb_stdlog,
			      "Bad checksum, sentsum=0x%x, csum=0x%x, buf=",
				  pktcsum, csum);
		fputstrn_filtered (buf, bc, 0, gdb_stdlog);
		fputs_filtered ("\n", gdb_stdlog);
	      }
	    /* Number of characters in buffer ignoring trailing
               NULL.  */
	    return -1;
	  }
	case '*':		/* Run length encoding.  */
          {
	    int repeat;
 	    csum += c;

	    c = readchar (remote_timeout);
	    csum += c;
	    repeat = c - ' ' + 3;	/* Compute repeat count.  */

	    /* The character before ``*'' is repeated.  */

	    if (repeat > 0 && repeat <= 255 && bc > 0)
	      {
		if (bc + repeat - 1 >= *sizeof_buf - 1)
		  {
		    /* Make some more room in the buffer.  */
		    *sizeof_buf += repeat;
		    *buf_p = xrealloc (*buf_p, *sizeof_buf);
		    buf = *buf_p;
		  }

		memset (&buf[bc], buf[bc - 1], repeat);
		bc += repeat;
		continue;
	      }

	    buf[bc] = '\0';
	    printf_filtered (_("Invalid run length encoding: %s\n"), buf);
	    return -1;
	  }
	default:
	  if (bc >= *sizeof_buf - 1)
	    {
	      /* Make some more room in the buffer.  */
	      *sizeof_buf *= 2;
	      *buf_p = xrealloc (*buf_p, *sizeof_buf);
	      buf = *buf_p;
	    }

	  buf[bc++] = c;
	  csum += c;
	  continue;
	}
    }
}

/* Read a packet from the remote machine, with error checking, and
   store it in *BUF.  Resize *BUF using xrealloc if necessary to hold
   the result, and update *SIZEOF_BUF.  If FOREVER, wait forever
   rather than timing out; this is used (in synchronous mode) to wait
   for a target that is is executing user code to stop.  */
/* FIXME: ezannoni 2000-02-01 this wrapper is necessary so that we
   don't have to change all the calls to getpkt to deal with the
   return value, because at the moment I don't know what the right
   thing to do it for those.  */
void
getpkt (char **buf,
	long *sizeof_buf,
	int forever)
{
  int timed_out;

  timed_out = getpkt_sane (buf, sizeof_buf, forever);
}


/* Read a packet from the remote machine, with error checking, and
   store it in *BUF.  Resize *BUF using xrealloc if necessary to hold
   the result, and update *SIZEOF_BUF.  If FOREVER, wait forever
   rather than timing out; this is used (in synchronous mode) to wait
   for a target that is is executing user code to stop.  If FOREVER ==
   0, this function is allowed to time out gracefully and return an
   indication of this to the caller.  Otherwise return the number
   of bytes read.  */
static int
getpkt_sane (char **buf, long *sizeof_buf, int forever)
{
  int c;
  int tries;
  int timeout;
  int val;

  strcpy (*buf, "timeout");

  if (forever)
    {
      timeout = watchdog > 0 ? watchdog : -1;
    }

  else
    timeout = remote_timeout;

#define MAX_TRIES 3

  for (tries = 1; tries <= MAX_TRIES; tries++)
    {
      /* This can loop forever if the remote side sends us characters
         continuously, but if it pauses, we'll get a zero from
         readchar because of timeout.  Then we'll count that as a
         retry.  */

      /* Note that we will only wait forever prior to the start of a
         packet.  After that, we expect characters to arrive at a
         brisk pace.  They should show up within remote_timeout
         intervals.  */

      do
	{
	  c = readchar (timeout);

	  if (c == SERIAL_TIMEOUT)
	    {
	      if (forever)	/* Watchdog went off?  Kill the target.  */
		{
		  QUIT;
		  target_mourn_inferior ();
		  error (_("Watchdog has expired.  Target detached."));
		}
	      if (remote_debug)
		fputs_filtered ("Timed out.\n", gdb_stdlog);
	      goto retry;
	    }
	}
      while (c != '$');

      /* We've found the start of a packet, now collect the data.  */

      val = read_frame (buf, sizeof_buf);

      if (val >= 0)
	{
	  if (remote_debug)
	    {
	      fprintf_unfiltered (gdb_stdlog, "Packet received: ");
	      fputstrn_unfiltered (*buf, val, 0, gdb_stdlog);
	      fprintf_unfiltered (gdb_stdlog, "\n");
	    }
	  serial_write (remote_desc, "+", 1);
	  return val;
	}

      /* Try the whole thing again.  */
    retry:
      serial_write (remote_desc, "-", 1);
    }

  /* We have tried hard enough, and just can't receive the packet.
     Give up.  */

  printf_unfiltered (_("Ignoring packet error, continuing...\n"));
  serial_write (remote_desc, "+", 1);
  return -1;
}
\f
static void
remote_kill (void)
{
  /* For some mysterious reason, wait_for_inferior calls kill instead of
     mourn after it gets TARGET_WAITKIND_SIGNALLED.  Work around it.  */
  if (kill_kludge)
    {
      kill_kludge = 0;
      target_mourn_inferior ();
      return;
    }

  /* Use catch_errors so the user can quit from gdb even when we aren't on
     speaking terms with the remote system.  */
  catch_errors ((catch_errors_ftype *) putpkt, "k", "", RETURN_MASK_ERROR);

  /* Don't wait for it to die.  I'm not really sure it matters whether
     we do or not.  For the existing stubs, kill is a noop.  */
  target_mourn_inferior ();
}

/* Async version of remote_kill.  */
static void
remote_async_kill (void)
{
  /* Unregister the file descriptor from the event loop.  */
  if (target_is_async_p ())
    serial_async (remote_desc, NULL, 0);

  /* For some mysterious reason, wait_for_inferior calls kill instead of
     mourn after it gets TARGET_WAITKIND_SIGNALLED.  Work around it.  */
  if (kill_kludge)
    {
      kill_kludge = 0;
      target_mourn_inferior ();
      return;
    }

  /* Use catch_errors so the user can quit from gdb even when we
     aren't on speaking terms with the remote system.  */
  catch_errors ((catch_errors_ftype *) putpkt, "k", "", RETURN_MASK_ERROR);

  /* Don't wait for it to die.  I'm not really sure it matters whether
     we do or not.  For the existing stubs, kill is a noop.  */
  target_mourn_inferior ();
}

static void
remote_mourn (void)
{
  remote_mourn_1 (&remote_ops);
}

static void
remote_async_mourn (void)
{
  remote_mourn_1 (&remote_async_ops);
}

static void
extended_remote_mourn (void)
{
  /* We do _not_ want to mourn the target like this; this will
     remove the extended remote target  from the target stack,
     and the next time the user says "run" it'll fail.

     FIXME: What is the right thing to do here?  */
#if 0
  remote_mourn_1 (&extended_remote_ops);
#endif
}

/* Worker function for remote_mourn.  */
static void
remote_mourn_1 (struct target_ops *target)
{
  unpush_target (target);
  generic_mourn_inferior ();
}

/* In the extended protocol we want to be able to do things like
   "run" and have them basically work as expected.  So we need
   a special create_inferior function.

   FIXME: One day add support for changing the exec file
   we're debugging, arguments and an environment.  */

static void
extended_remote_create_inferior (char *exec_file, char *args,
				 char **env, int from_tty)
{
  /* Rip out the breakpoints; we'll reinsert them after restarting
     the remote server.  */
  remove_breakpoints ();

  /* Now restart the remote server.  */
  extended_remote_restart ();

  /* Now put the breakpoints back in.  This way we're safe if the
     restart function works via a unix fork on the remote side.  */
  insert_breakpoints ();

  /* Clean up from the last time we were running.  */
  clear_proceed_status ();
}

/* Async version of extended_remote_create_inferior.  */
static void
extended_remote_async_create_inferior (char *exec_file, char *args,
				       char **env, int from_tty)
{
  /* Rip out the breakpoints; we'll reinsert them after restarting
     the remote server.  */
  remove_breakpoints ();

  /* If running asynchronously, register the target file descriptor
     with the event loop.  */
  if (target_can_async_p ())
    target_async (inferior_event_handler, 0);

  /* Now restart the remote server.  */
  extended_remote_restart ();

  /* Now put the breakpoints back in.  This way we're safe if the
     restart function works via a unix fork on the remote side.  */
  insert_breakpoints ();

  /* Clean up from the last time we were running.  */
  clear_proceed_status ();
}
\f

/* On some machines, e.g. 68k, we may use a different breakpoint
   instruction than other targets; in those use
   DEPRECATED_REMOTE_BREAKPOINT instead of just BREAKPOINT_FROM_PC.
   Also, bi-endian targets may define
   DEPRECATED_LITTLE_REMOTE_BREAKPOINT and
   DEPRECATED_BIG_REMOTE_BREAKPOINT.  If none of these are defined, we
   just call the standard routines that are in mem-break.c.  */

/* NOTE: cagney/2003-06-08: This is silly.  A remote and simulator
   target should use an identical BREAKPOINT_FROM_PC.  As for native,
   the ARCH-OS-tdep.c code can override the default.  */

#if defined (DEPRECATED_LITTLE_REMOTE_BREAKPOINT) && defined (DEPRECATED_BIG_REMOTE_BREAKPOINT) && !defined(DEPRECATED_REMOTE_BREAKPOINT)
#define DEPRECATED_REMOTE_BREAKPOINT
#endif

#ifdef DEPRECATED_REMOTE_BREAKPOINT

/* If the target isn't bi-endian, just pretend it is.  */
#if !defined (DEPRECATED_LITTLE_REMOTE_BREAKPOINT) && !defined (DEPRECATED_BIG_REMOTE_BREAKPOINT)
#define DEPRECATED_LITTLE_REMOTE_BREAKPOINT DEPRECATED_REMOTE_BREAKPOINT
#define DEPRECATED_BIG_REMOTE_BREAKPOINT DEPRECATED_REMOTE_BREAKPOINT
#endif

static unsigned char big_break_insn[] = DEPRECATED_BIG_REMOTE_BREAKPOINT;
static unsigned char little_break_insn[] = DEPRECATED_LITTLE_REMOTE_BREAKPOINT;

#endif /* DEPRECATED_REMOTE_BREAKPOINT */

/* Insert a breakpoint.  On targets that have software breakpoint
   support, we ask the remote target to do the work; on targets
   which don't, we insert a traditional memory breakpoint.  */

static int
remote_insert_breakpoint (struct bp_target_info *bp_tgt)
{
  CORE_ADDR addr = bp_tgt->placed_address;
  struct remote_state *rs = get_remote_state ();
#ifdef DEPRECATED_REMOTE_BREAKPOINT
  int val;
#endif

  /* Try the "Z" s/w breakpoint packet if it is not already disabled.
     If it succeeds, then set the support to PACKET_ENABLE.  If it
     fails, and the user has explicitly requested the Z support then
     report an error, otherwise, mark it disabled and go on.  */

  if (remote_protocol_packets[PACKET_Z0].support != PACKET_DISABLE)
    {
      char *p = rs->buf;

      *(p++) = 'Z';
      *(p++) = '0';
      *(p++) = ',';
      BREAKPOINT_FROM_PC (&bp_tgt->placed_address, &bp_tgt->placed_size);
      addr = (ULONGEST) remote_address_masked (bp_tgt->placed_address);
      p += hexnumstr (p, addr);
      sprintf (p, ",%d", bp_tgt->placed_size);

      putpkt (rs->buf);
      getpkt (&rs->buf, &rs->buf_size, 0);

      switch (packet_ok (rs->buf, &remote_protocol_packets[PACKET_Z0]))
	{
	case PACKET_ERROR:
	  return -1;
	case PACKET_OK:
	  return 0;
	case PACKET_UNKNOWN:
	  break;
	}
    }

#ifdef DEPRECATED_REMOTE_BREAKPOINT
  bp_tgt->placed_size = bp_tgt->shadow_len = sizeof big_break_insn;
  val = target_read_memory (addr, bp_tgt->shadow_contents, bp_tgt->shadow_len);

  if (val == 0)
    {
      if (TARGET_BYTE_ORDER == BFD_ENDIAN_BIG)
	val = target_write_memory (addr, (char *) big_break_insn,
				   sizeof big_break_insn);
      else
	val = target_write_memory (addr, (char *) little_break_insn,
				   sizeof little_break_insn);
    }

  return val;
#else
  return memory_insert_breakpoint (bp_tgt);
#endif /* DEPRECATED_REMOTE_BREAKPOINT */
}

static int
remote_remove_breakpoint (struct bp_target_info *bp_tgt)
{
  CORE_ADDR addr = bp_tgt->placed_address;
  struct remote_state *rs = get_remote_state ();
  int bp_size;

  if (remote_protocol_packets[PACKET_Z0].support != PACKET_DISABLE)
    {
      char *p = rs->buf;

      *(p++) = 'z';
      *(p++) = '0';
      *(p++) = ',';

      addr = (ULONGEST) remote_address_masked (bp_tgt->placed_address);
      p += hexnumstr (p, addr);
      sprintf (p, ",%d", bp_tgt->placed_size);

      putpkt (rs->buf);
      getpkt (&rs->buf, &rs->buf_size, 0);

      return (rs->buf[0] == 'E');
    }

#ifdef DEPRECATED_REMOTE_BREAKPOINT
  return target_write_memory (bp_tgt->placed_address, bp_tgt->shadow_contents,
			      bp_tgt->shadow_len);
#else
  return memory_remove_breakpoint (bp_tgt);
#endif /* DEPRECATED_REMOTE_BREAKPOINT */
}

static int
watchpoint_to_Z_packet (int type)
{
  switch (type)
    {
    case hw_write:
      return Z_PACKET_WRITE_WP;
      break;
    case hw_read:
      return Z_PACKET_READ_WP;
      break;
    case hw_access:
      return Z_PACKET_ACCESS_WP;
      break;
    default:
      internal_error (__FILE__, __LINE__,
		      _("hw_bp_to_z: bad watchpoint type %d"), type);
    }
}

static int
remote_insert_watchpoint (CORE_ADDR addr, int len, int type)
{
  struct remote_state *rs = get_remote_state ();
  char *p;
  enum Z_packet_type packet = watchpoint_to_Z_packet (type);

  if (remote_protocol_packets[PACKET_Z0 + packet].support == PACKET_DISABLE)
    return -1;

  sprintf (rs->buf, "Z%x,", packet);
  p = strchr (rs->buf, '\0');
  addr = remote_address_masked (addr);
  p += hexnumstr (p, (ULONGEST) addr);
  sprintf (p, ",%x", len);

  putpkt (rs->buf);
  getpkt (&rs->buf, &rs->buf_size, 0);

  switch (packet_ok (rs->buf, &remote_protocol_packets[PACKET_Z0 + packet]))
    {
    case PACKET_ERROR:
    case PACKET_UNKNOWN:
      return -1;
    case PACKET_OK:
      return 0;
    }
  internal_error (__FILE__, __LINE__,
		  _("remote_insert_watchpoint: reached end of function"));
}


static int
remote_remove_watchpoint (CORE_ADDR addr, int len, int type)
{
  struct remote_state *rs = get_remote_state ();
  char *p;
  enum Z_packet_type packet = watchpoint_to_Z_packet (type);

  if (remote_protocol_packets[PACKET_Z0 + packet].support == PACKET_DISABLE)
    return -1;

  sprintf (rs->buf, "z%x,", packet);
  p = strchr (rs->buf, '\0');
  addr = remote_address_masked (addr);
  p += hexnumstr (p, (ULONGEST) addr);
  sprintf (p, ",%x", len);
  putpkt (rs->buf);
  getpkt (&rs->buf, &rs->buf_size, 0);

  switch (packet_ok (rs->buf, &remote_protocol_packets[PACKET_Z0 + packet]))
    {
    case PACKET_ERROR:
    case PACKET_UNKNOWN:
      return -1;
    case PACKET_OK:
      return 0;
    }
  internal_error (__FILE__, __LINE__,
		  _("remote_remove_watchpoint: reached end of function"));
}


int remote_hw_watchpoint_limit = -1;
int remote_hw_breakpoint_limit = -1;

static int
remote_check_watch_resources (int type, int cnt, int ot)
{
  if (type == bp_hardware_breakpoint)
    {
      if (remote_hw_breakpoint_limit == 0)
	return 0;
      else if (remote_hw_breakpoint_limit < 0)
	return 1;
      else if (cnt <= remote_hw_breakpoint_limit)
	return 1;
    }
  else
    {
      if (remote_hw_watchpoint_limit == 0)
	return 0;
      else if (remote_hw_watchpoint_limit < 0)
	return 1;
      else if (ot)
	return -1;
      else if (cnt <= remote_hw_watchpoint_limit)
	return 1;
    }
  return -1;
}

static int
remote_stopped_by_watchpoint (void)
{
    return remote_stopped_by_watchpoint_p;
}

extern int stepped_after_stopped_by_watchpoint;

static int
remote_stopped_data_address (struct target_ops *target, CORE_ADDR *addr_p)
{
  int rc = 0;
  if (remote_stopped_by_watchpoint ()
      || stepped_after_stopped_by_watchpoint)
    {
      *addr_p = remote_watch_data_address;
      rc = 1;
    }

  return rc;
}


static int
remote_insert_hw_breakpoint (struct bp_target_info *bp_tgt)
{
  CORE_ADDR addr;
  struct remote_state *rs = get_remote_state ();
  char *p = rs->buf;

  /* The length field should be set to the size of a breakpoint
     instruction, even though we aren't inserting one ourselves.  */

  BREAKPOINT_FROM_PC (&bp_tgt->placed_address, &bp_tgt->placed_size);

  if (remote_protocol_packets[PACKET_Z1].support == PACKET_DISABLE)
    return -1;

  *(p++) = 'Z';
  *(p++) = '1';
  *(p++) = ',';

  addr = remote_address_masked (bp_tgt->placed_address);
  p += hexnumstr (p, (ULONGEST) addr);
  sprintf (p, ",%x", bp_tgt->placed_size);

  putpkt (rs->buf);
  getpkt (&rs->buf, &rs->buf_size, 0);

  switch (packet_ok (rs->buf, &remote_protocol_packets[PACKET_Z1]))
    {
    case PACKET_ERROR:
    case PACKET_UNKNOWN:
      return -1;
    case PACKET_OK:
      return 0;
    }
  internal_error (__FILE__, __LINE__,
		  _("remote_insert_hw_breakpoint: reached end of function"));
}


static int
remote_remove_hw_breakpoint (struct bp_target_info *bp_tgt)
{
  CORE_ADDR addr;
  struct remote_state *rs = get_remote_state ();
  char *p = rs->buf;

  if (remote_protocol_packets[PACKET_Z1].support == PACKET_DISABLE)
    return -1;

  *(p++) = 'z';
  *(p++) = '1';
  *(p++) = ',';

  addr = remote_address_masked (bp_tgt->placed_address);
  p += hexnumstr (p, (ULONGEST) addr);
  sprintf (p, ",%x", bp_tgt->placed_size);

  putpkt (rs->buf);
  getpkt (&rs->buf, &rs->buf_size, 0);

  switch (packet_ok (rs->buf, &remote_protocol_packets[PACKET_Z1]))
    {
    case PACKET_ERROR:
    case PACKET_UNKNOWN:
      return -1;
    case PACKET_OK:
      return 0;
    }
  internal_error (__FILE__, __LINE__,
		  _("remote_remove_hw_breakpoint: reached end of function"));
}

/* Some targets are only capable of doing downloads, and afterwards
   they switch to the remote serial protocol.  This function provides
   a clean way to get from the download target to the remote target.
   It's basically just a wrapper so that we don't have to expose any
   of the internal workings of remote.c.

   Prior to calling this routine, you should shutdown the current
   target code, else you will get the "A program is being debugged
   already..." message.  Usually a call to pop_target() suffices.  */

void
push_remote_target (char *name, int from_tty)
{
  printf_filtered (_("Switching to remote protocol\n"));
  remote_open (name, from_tty);
}

/* Table used by the crc32 function to calcuate the checksum.  */

static unsigned long crc32_table[256] =
{0, 0};

static unsigned long
crc32 (unsigned char *buf, int len, unsigned int crc)
{
  if (!crc32_table[1])
    {
      /* Initialize the CRC table and the decoding table.  */
      int i, j;
      unsigned int c;

      for (i = 0; i < 256; i++)
	{
	  for (c = i << 24, j = 8; j > 0; --j)
	    c = c & 0x80000000 ? (c << 1) ^ 0x04c11db7 : (c << 1);
	  crc32_table[i] = c;
	}
    }

  while (len--)
    {
      crc = (crc << 8) ^ crc32_table[((crc >> 24) ^ *buf) & 255];
      buf++;
    }
  return crc;
}

/* compare-sections command

   With no arguments, compares each loadable section in the exec bfd
   with the same memory range on the target, and reports mismatches.
   Useful for verifying the image on the target against the exec file.
   Depends on the target understanding the new "qCRC:" request.  */

/* FIXME: cagney/1999-10-26: This command should be broken down into a
   target method (target verify memory) and generic version of the
   actual command.  This will allow other high-level code (especially
   generic_load()) to make use of this target functionality.  */

static void
compare_sections_command (char *args, int from_tty)
{
  struct remote_state *rs = get_remote_state ();
  asection *s;
  unsigned long host_crc, target_crc;
  extern bfd *exec_bfd;
  struct cleanup *old_chain;
  char *tmp;
  char *sectdata;
  const char *sectname;
  bfd_size_type size;
  bfd_vma lma;
  int matched = 0;
  int mismatched = 0;

  if (!exec_bfd)
    error (_("command cannot be used without an exec file"));
  if (!current_target.to_shortname ||
      strcmp (current_target.to_shortname, "remote") != 0)
    error (_("command can only be used with remote target"));

  for (s = exec_bfd->sections; s; s = s->next)
    {
      if (!(s->flags & SEC_LOAD))
	continue;		/* skip non-loadable section */

      size = bfd_get_section_size (s);
      if (size == 0)
	continue;		/* skip zero-length section */

      sectname = bfd_get_section_name (exec_bfd, s);
      if (args && strcmp (args, sectname) != 0)
	continue;		/* not the section selected by user */

      matched = 1;		/* do this section */
      lma = s->lma;
      /* FIXME: assumes lma can fit into long.  */
      xsnprintf (rs->buf, get_remote_packet_size (), "qCRC:%lx,%lx",
		 (long) lma, (long) size);
      putpkt (rs->buf);

      /* Be clever; compute the host_crc before waiting for target
	 reply.  */
      sectdata = xmalloc (size);
      old_chain = make_cleanup (xfree, sectdata);
      bfd_get_section_contents (exec_bfd, s, sectdata, 0, size);
      host_crc = crc32 ((unsigned char *) sectdata, size, 0xffffffff);

      getpkt (&rs->buf, &rs->buf_size, 0);
      if (rs->buf[0] == 'E')
	error (_("target memory fault, section %s, range 0x%s -- 0x%s"),
	       sectname, paddr (lma), paddr (lma + size));
      if (rs->buf[0] != 'C')
	error (_("remote target does not support this operation"));

      for (target_crc = 0, tmp = &rs->buf[1]; *tmp; tmp++)
	target_crc = target_crc * 16 + fromhex (*tmp);

      printf_filtered ("Section %s, range 0x%s -- 0x%s: ",
		       sectname, paddr (lma), paddr (lma + size));
      if (host_crc == target_crc)
	printf_filtered ("matched.\n");
      else
	{
	  printf_filtered ("MIS-MATCHED!\n");
	  mismatched++;
	}

      do_cleanups (old_chain);
    }
  if (mismatched > 0)
    warning (_("One or more sections of the remote executable does not match\n\
the loaded file\n"));
  if (args && !matched)
    printf_filtered (_("No loaded section named '%s'.\n"), args);
}

/* Read OBJECT_NAME/ANNEX from the remote target using a qXfer packet.
   Data at OFFSET, of up to LEN bytes, is read into READBUF; the
   number of bytes read is returned, or 0 for EOF, or -1 for error.
   The number of bytes read may be less than LEN without indicating an
   EOF.  PACKET is checked and updated to indicate whether the remote
   target supports this object.  */

static LONGEST
remote_read_qxfer (struct target_ops *ops, const char *object_name,
		   const char *annex,
		   gdb_byte *readbuf, ULONGEST offset, LONGEST len,
		   struct packet_config *packet)
{
  static char *finished_object;
  static char *finished_annex;
  static ULONGEST finished_offset;

  struct remote_state *rs = get_remote_state ();
  unsigned int total = 0;
  LONGEST i, n, packet_len;

  if (packet->support == PACKET_DISABLE)
    return -1;

  /* Check whether we've cached an end-of-object packet that matches
     this request.  */
  if (finished_object)
    {
      if (strcmp (object_name, finished_object) == 0
	  && strcmp (annex ? annex : "", finished_annex) == 0
	  && offset == finished_offset)
	return 0;

      /* Otherwise, we're now reading something different.  Discard
	 the cache.  */
      xfree (finished_object);
      xfree (finished_annex);
      finished_object = NULL;
      finished_annex = NULL;
    }

  /* Request only enough to fit in a single packet.  The actual data
     may not, since we don't know how much of it will need to be escaped;
     the target is free to respond with slightly less data.  We subtract
     five to account for the response type and the protocol frame.  */
  n = min (get_remote_packet_size () - 5, len);
  snprintf (rs->buf, get_remote_packet_size () - 4, "qXfer:%s:read:%s:%s,%s",
	    object_name, annex ? annex : "",
	    phex_nz (offset, sizeof offset),
	    phex_nz (n, sizeof n));
  i = putpkt (rs->buf);
  if (i < 0)
    return -1;

  rs->buf[0] = '\0';
  packet_len = getpkt_sane (&rs->buf, &rs->buf_size, 0);
  if (packet_len < 0 || packet_ok (rs->buf, packet) != PACKET_OK)
    return -1;

  if (rs->buf[0] != 'l' && rs->buf[0] != 'm')
    error (_("Unknown remote qXfer reply: %s"), rs->buf);

  /* 'm' means there is (or at least might be) more data after this
     batch.  That does not make sense unless there's at least one byte
     of data in this reply.  */
  if (rs->buf[0] == 'm' && packet_len == 1)
    error (_("Remote qXfer reply contained no data."));

  /* Got some data.  */
  i = remote_unescape_input (rs->buf + 1, packet_len - 1, readbuf, n);

  /* 'l' is an EOF marker, possibly including a final block of data,
     or possibly empty.  Record it to bypass the next read, if one is
     issued.  */
  if (rs->buf[0] == 'l')
    {
      finished_object = xstrdup (object_name);
      finished_annex = xstrdup (annex ? annex : "");
      finished_offset = offset + i;
    }

  return i;
}

static LONGEST
remote_xfer_partial (struct target_ops *ops, enum target_object object,
		     const char *annex, gdb_byte *readbuf,
		     const gdb_byte *writebuf, ULONGEST offset, LONGEST len)
{
  struct remote_state *rs = get_remote_state ();
  int i;
  char *p2;
  char query_type;

  /* Handle memory using the standard memory routines.  */
  if (object == TARGET_OBJECT_MEMORY)
    {
      int xfered;
      errno = 0;

      if (writebuf != NULL)
	xfered = remote_write_bytes (offset, writebuf, len);
      else
	xfered = remote_read_bytes (offset, readbuf, len);

      if (xfered > 0)
	return xfered;
      else if (xfered == 0 && errno == 0)
	return 0;
      else
	return -1;
    }

  /* Only handle flash writes.  */
  if (writebuf != NULL)
    {
      LONGEST xfered;

      switch (object)
	{
	case TARGET_OBJECT_FLASH:
	  xfered = remote_flash_write (ops, offset, len, writebuf);

	  if (xfered > 0)
	    return xfered;
	  else if (xfered == 0 && errno == 0)
	    return 0;
	  else
	    return -1;

	default:
	  return -1;
	}
    }

  /* Map pre-existing objects onto letters.  DO NOT do this for new
     objects!!!  Instead specify new query packets.  */
  switch (object)
    {
    case TARGET_OBJECT_AVR:
      query_type = 'R';
      break;

    case TARGET_OBJECT_AUXV:
      gdb_assert (annex == NULL);
      return remote_read_qxfer (ops, "auxv", annex, readbuf, offset, len,
				&remote_protocol_packets[PACKET_qXfer_auxv]);

    case TARGET_OBJECT_MEMORY_MAP:
      gdb_assert (annex == NULL);
      return remote_read_qxfer (ops, "memory-map", annex, readbuf, offset, len,
				&remote_protocol_packets[PACKET_qXfer_memory_map]);

    default:
      return -1;
    }

  /* Note: a zero OFFSET and LEN can be used to query the minimum
     buffer size.  */
  if (offset == 0 && len == 0)
    return (get_remote_packet_size ());
  /* Minimum outbuf size is get_remote_packet_size (). If LEN is not
     large enough let the caller deal with it.  */
  if (len < get_remote_packet_size ())
    return -1;
  len = get_remote_packet_size ();

  /* Except for querying the minimum buffer size, target must be open.  */
  if (!remote_desc)
    error (_("remote query is only available after target open"));

  gdb_assert (annex != NULL);
  gdb_assert (readbuf != NULL);

  p2 = rs->buf;
  *p2++ = 'q';
  *p2++ = query_type;

  /* We used one buffer char for the remote protocol q command and
     another for the query type.  As the remote protocol encapsulation
     uses 4 chars plus one extra in case we are debugging
     (remote_debug), we have PBUFZIZ - 7 left to pack the query
     string.  */
  i = 0;
  while (annex[i] && (i < (get_remote_packet_size () - 8)))
    {
      /* Bad caller may have sent forbidden characters.  */
      gdb_assert (isprint (annex[i]) && annex[i] != '$' && annex[i] != '#');
      *p2++ = annex[i];
      i++;
    }
  *p2 = '\0';
  gdb_assert (annex[i] == '\0');

  i = putpkt (rs->buf);
  if (i < 0)
    return i;

  getpkt (&rs->buf, &rs->buf_size, 0);
  strcpy ((char *) readbuf, rs->buf);

  return strlen ((char *) readbuf);
}

static void
remote_rcmd (char *command,
	     struct ui_file *outbuf)
{
  struct remote_state *rs = get_remote_state ();
  char *p = rs->buf;

  if (!remote_desc)
    error (_("remote rcmd is only available after target open"));

  /* Send a NULL command across as an empty command.  */
  if (command == NULL)
    command = "";

  /* The query prefix.  */
  strcpy (rs->buf, "qRcmd,");
  p = strchr (rs->buf, '\0');

  if ((strlen (rs->buf) + strlen (command) * 2 + 8/*misc*/) > get_remote_packet_size ())
    error (_("\"monitor\" command ``%s'' is too long."), command);

  /* Encode the actual command.  */
  bin2hex ((gdb_byte *) command, p, 0);

  if (putpkt (rs->buf) < 0)
    error (_("Communication problem with target."));

  /* get/display the response */
  while (1)
    {
      char *buf;

      /* XXX - see also tracepoint.c:remote_get_noisy_reply().  */
      rs->buf[0] = '\0';
      getpkt (&rs->buf, &rs->buf_size, 0);
      buf = rs->buf;
      if (buf[0] == '\0')
	error (_("Target does not support this command."));
      if (buf[0] == 'O' && buf[1] != 'K')
	{
	  remote_console_output (buf + 1); /* 'O' message from stub.  */
	  continue;
	}
      if (strcmp (buf, "OK") == 0)
	break;
      if (strlen (buf) == 3 && buf[0] == 'E'
	  && isdigit (buf[1]) && isdigit (buf[2]))
	{
	  error (_("Protocol error with Rcmd"));
	}
      for (p = buf; p[0] != '\0' && p[1] != '\0'; p += 2)
	{
	  char c = (fromhex (p[0]) << 4) + fromhex (p[1]);
	  fputc_unfiltered (c, outbuf);
	}
      break;
    }
}

static VEC(mem_region_s) *
remote_memory_map (struct target_ops *ops)
{
  VEC(mem_region_s) *result = NULL;
  char *text = target_read_stralloc (&current_target,
				     TARGET_OBJECT_MEMORY_MAP, NULL);

  if (text)
    {
      struct cleanup *back_to = make_cleanup (xfree, text);
      result = parse_memory_map (text);
      do_cleanups (back_to);
    }

  return result;
}

static void
packet_command (char *args, int from_tty)
{
  struct remote_state *rs = get_remote_state ();

  if (!remote_desc)
    error (_("command can only be used with remote target"));

  if (!args)
    error (_("remote-packet command requires packet text as argument"));

  puts_filtered ("sending: ");
  print_packet (args);
  puts_filtered ("\n");
  putpkt (args);

  getpkt (&rs->buf, &rs->buf_size, 0);
  puts_filtered ("received: ");
  print_packet (rs->buf);
  puts_filtered ("\n");
}

#if 0
/* --------- UNIT_TEST for THREAD oriented PACKETS ------------------- */

static void display_thread_info (struct gdb_ext_thread_info *info);

static void threadset_test_cmd (char *cmd, int tty);

static void threadalive_test (char *cmd, int tty);

static void threadlist_test_cmd (char *cmd, int tty);

int get_and_display_threadinfo (threadref *ref);

static void threadinfo_test_cmd (char *cmd, int tty);

static int thread_display_step (threadref *ref, void *context);

static void threadlist_update_test_cmd (char *cmd, int tty);

static void init_remote_threadtests (void);

#define SAMPLE_THREAD  0x05060708	/* Truncated 64 bit threadid.  */

static void
threadset_test_cmd (char *cmd, int tty)
{
  int sample_thread = SAMPLE_THREAD;

  printf_filtered (_("Remote threadset test\n"));
  set_thread (sample_thread, 1);
}


static void
threadalive_test (char *cmd, int tty)
{
  int sample_thread = SAMPLE_THREAD;

  if (remote_thread_alive (pid_to_ptid (sample_thread)))
    printf_filtered ("PASS: Thread alive test\n");
  else
    printf_filtered ("FAIL: Thread alive test\n");
}

void output_threadid (char *title, threadref *ref);

void
output_threadid (char *title, threadref *ref)
{
  char hexid[20];

  pack_threadid (&hexid[0], ref);	/* Convert threead id into hex.  */
  hexid[16] = 0;
  printf_filtered ("%s  %s\n", title, (&hexid[0]));
}

static void
threadlist_test_cmd (char *cmd, int tty)
{
  int startflag = 1;
  threadref nextthread;
  int done, result_count;
  threadref threadlist[3];

  printf_filtered ("Remote Threadlist test\n");
  if (!remote_get_threadlist (startflag, &nextthread, 3, &done,
			      &result_count, &threadlist[0]))
    printf_filtered ("FAIL: threadlist test\n");
  else
    {
      threadref *scan = threadlist;
      threadref *limit = scan + result_count;

      while (scan < limit)
	output_threadid (" thread ", scan++);
    }
}

void
display_thread_info (struct gdb_ext_thread_info *info)
{
  output_threadid ("Threadid: ", &info->threadid);
  printf_filtered ("Name: %s\n ", info->shortname);
  printf_filtered ("State: %s\n", info->display);
  printf_filtered ("other: %s\n\n", info->more_display);
}

int
get_and_display_threadinfo (threadref *ref)
{
  int result;
  int set;
  struct gdb_ext_thread_info threadinfo;

  set = TAG_THREADID | TAG_EXISTS | TAG_THREADNAME
    | TAG_MOREDISPLAY | TAG_DISPLAY;
  if (0 != (result = remote_get_threadinfo (ref, set, &threadinfo)))
    display_thread_info (&threadinfo);
  return result;
}

static void
threadinfo_test_cmd (char *cmd, int tty)
{
  int athread = SAMPLE_THREAD;
  threadref thread;
  int set;

  int_to_threadref (&thread, athread);
  printf_filtered ("Remote Threadinfo test\n");
  if (!get_and_display_threadinfo (&thread))
    printf_filtered ("FAIL cannot get thread info\n");
}

static int
thread_display_step (threadref *ref, void *context)
{
  /* output_threadid(" threadstep ",ref); *//* simple test */
  return get_and_display_threadinfo (ref);
}

static void
threadlist_update_test_cmd (char *cmd, int tty)
{
  printf_filtered ("Remote Threadlist update test\n");
  remote_threadlist_iterator (thread_display_step, 0, CRAZY_MAX_THREADS);
}

static void
init_remote_threadtests (void)
{
  add_com ("tlist", class_obscure, threadlist_test_cmd, _("\
Fetch and print the remote list of thread identifiers, one pkt only"));
  add_com ("tinfo", class_obscure, threadinfo_test_cmd,
	   _("Fetch and display info about one thread"));
  add_com ("tset", class_obscure, threadset_test_cmd,
	   _("Test setting to a different thread"));
  add_com ("tupd", class_obscure, threadlist_update_test_cmd,
	   _("Iterate through updating all remote thread info"));
  add_com ("talive", class_obscure, threadalive_test,
	   _(" Remote thread alive test "));
}

#endif /* 0 */

/* Convert a thread ID to a string.  Returns the string in a static
   buffer.  */

static char *
remote_pid_to_str (ptid_t ptid)
{
  static char buf[32];

  xsnprintf (buf, sizeof buf, "Thread %d", ptid_get_pid (ptid));
  return buf;
}

/* Get the address of the thread local variable in OBJFILE which is
   stored at OFFSET within the thread local storage for thread PTID.  */

static CORE_ADDR
remote_get_thread_local_address (ptid_t ptid, CORE_ADDR lm, CORE_ADDR offset)
{
  if (remote_protocol_packets[PACKET_qGetTLSAddr].support != PACKET_DISABLE)
    {
      struct remote_state *rs = get_remote_state ();
      char *p = rs->buf;
      enum packet_result result;

      strcpy (p, "qGetTLSAddr:");
      p += strlen (p);
      p += hexnumstr (p, PIDGET (ptid));
      *p++ = ',';
      p += hexnumstr (p, offset);
      *p++ = ',';
      p += hexnumstr (p, lm);
      *p++ = '\0';

      putpkt (rs->buf);
      getpkt (&rs->buf, &rs->buf_size, 0);
      result = packet_ok (rs->buf, &remote_protocol_packets[PACKET_qGetTLSAddr]);
      if (result == PACKET_OK)
	{
	  ULONGEST result;

	  unpack_varlen_hex (rs->buf, &result);
	  return result;
	}
      else if (result == PACKET_UNKNOWN)
	throw_error (TLS_GENERIC_ERROR,
		     _("Remote target doesn't support qGetTLSAddr packet"));
      else
	throw_error (TLS_GENERIC_ERROR,
		     _("Remote target failed to process qGetTLSAddr request"));
    }
  else
    throw_error (TLS_GENERIC_ERROR,
		 _("TLS not supported or disabled on this target"));
  /* Not reached.  */
  return 0;
}

static void
init_remote_ops (void)
{
  remote_ops.to_shortname = "remote";
  remote_ops.to_longname = "Remote serial target in gdb-specific protocol";
  remote_ops.to_doc =
    "Use a remote computer via a serial line, using a gdb-specific protocol.\n\
Specify the serial device it is connected to\n\
(e.g. /dev/ttyS0, /dev/ttya, COM1, etc.).";
  remote_ops.to_open = remote_open;
  remote_ops.to_close = remote_close;
  remote_ops.to_detach = remote_detach;
  remote_ops.to_disconnect = remote_disconnect;
  remote_ops.to_resume = remote_resume;
  remote_ops.to_wait = remote_wait;
  remote_ops.to_fetch_registers = remote_fetch_registers;
  remote_ops.to_store_registers = remote_store_registers;
  remote_ops.to_prepare_to_store = remote_prepare_to_store;
  remote_ops.deprecated_xfer_memory = remote_xfer_memory;
  remote_ops.to_files_info = remote_files_info;
  remote_ops.to_insert_breakpoint = remote_insert_breakpoint;
  remote_ops.to_remove_breakpoint = remote_remove_breakpoint;
  remote_ops.to_stopped_by_watchpoint = remote_stopped_by_watchpoint;
  remote_ops.to_stopped_data_address = remote_stopped_data_address;
  remote_ops.to_can_use_hw_breakpoint = remote_check_watch_resources;
  remote_ops.to_insert_hw_breakpoint = remote_insert_hw_breakpoint;
  remote_ops.to_remove_hw_breakpoint = remote_remove_hw_breakpoint;
  remote_ops.to_insert_watchpoint = remote_insert_watchpoint;
  remote_ops.to_remove_watchpoint = remote_remove_watchpoint;
  remote_ops.to_kill = remote_kill;
  remote_ops.to_load = generic_load;
  remote_ops.to_mourn_inferior = remote_mourn;
  remote_ops.to_thread_alive = remote_thread_alive;
  remote_ops.to_find_new_threads = remote_threads_info;
  remote_ops.to_pid_to_str = remote_pid_to_str;
  remote_ops.to_extra_thread_info = remote_threads_extra_info;
  remote_ops.to_stop = remote_stop;
  remote_ops.to_xfer_partial = remote_xfer_partial;
  remote_ops.to_rcmd = remote_rcmd;
  remote_ops.to_get_thread_local_address = remote_get_thread_local_address;
  remote_ops.to_stratum = process_stratum;
  remote_ops.to_has_all_memory = 1;
  remote_ops.to_has_memory = 1;
  remote_ops.to_has_stack = 1;
  remote_ops.to_has_registers = 1;
  remote_ops.to_has_execution = 1;
  remote_ops.to_has_thread_control = tc_schedlock;	/* can lock scheduler */
  remote_ops.to_magic = OPS_MAGIC;
  remote_ops.to_memory_map = remote_memory_map;
  remote_ops.to_flash_erase = remote_flash_erase;
  remote_ops.to_flash_done = remote_flash_done;
}

/* Set up the extended remote vector by making a copy of the standard
   remote vector and adding to it.  */

static void
init_extended_remote_ops (void)
{
  extended_remote_ops = remote_ops;

  extended_remote_ops.to_shortname = "extended-remote";
  extended_remote_ops.to_longname =
    "Extended remote serial target in gdb-specific protocol";
  extended_remote_ops.to_doc =
    "Use a remote computer via a serial line, using a gdb-specific protocol.\n\
Specify the serial device it is connected to (e.g. /dev/ttya).",
    extended_remote_ops.to_open = extended_remote_open;
  extended_remote_ops.to_create_inferior = extended_remote_create_inferior;
  extended_remote_ops.to_mourn_inferior = extended_remote_mourn;
}

static int
remote_can_async_p (void)
{
  /* We're async whenever the serial device is.  */
  return (current_target.to_async_mask_value) && serial_can_async_p (remote_desc);
}

static int
remote_is_async_p (void)
{
  /* We're async whenever the serial device is.  */
  return (current_target.to_async_mask_value) && serial_is_async_p (remote_desc);
}

/* Pass the SERIAL event on and up to the client.  One day this code
   will be able to delay notifying the client of an event until the
   point where an entire packet has been received.  */

static void (*async_client_callback) (enum inferior_event_type event_type,
				      void *context);
static void *async_client_context;
static serial_event_ftype remote_async_serial_handler;

static void
remote_async_serial_handler (struct serial *scb, void *context)
{
  /* Don't propogate error information up to the client.  Instead let
     the client find out about the error by querying the target.  */
  async_client_callback (INF_REG_EVENT, async_client_context);
}

static void
remote_async (void (*callback) (enum inferior_event_type event_type,
				void *context), void *context)
{
  if (current_target.to_async_mask_value == 0)
    internal_error (__FILE__, __LINE__,
		    _("Calling remote_async when async is masked"));

  if (callback != NULL)
    {
      serial_async (remote_desc, remote_async_serial_handler, NULL);
      async_client_callback = callback;
      async_client_context = context;
    }
  else
    serial_async (remote_desc, NULL, NULL);
}

/* Target async and target extended-async.

   This are temporary targets, until it is all tested.  Eventually
   async support will be incorporated int the usual 'remote'
   target.  */

static void
init_remote_async_ops (void)
{
  remote_async_ops.to_shortname = "async";
  remote_async_ops.to_longname =
    "Remote serial target in async version of the gdb-specific protocol";
  remote_async_ops.to_doc =
    "Use a remote computer via a serial line, using a gdb-specific protocol.\n\
Specify the serial device it is connected to (e.g. /dev/ttya).";
  remote_async_ops.to_open = remote_async_open;
  remote_async_ops.to_close = remote_close;
  remote_async_ops.to_detach = remote_detach;
  remote_async_ops.to_disconnect = remote_disconnect;
  remote_async_ops.to_resume = remote_async_resume;
  remote_async_ops.to_wait = remote_async_wait;
  remote_async_ops.to_fetch_registers = remote_fetch_registers;
  remote_async_ops.to_store_registers = remote_store_registers;
  remote_async_ops.to_prepare_to_store = remote_prepare_to_store;
  remote_async_ops.deprecated_xfer_memory = remote_xfer_memory;
  remote_async_ops.to_files_info = remote_files_info;
  remote_async_ops.to_insert_breakpoint = remote_insert_breakpoint;
  remote_async_ops.to_remove_breakpoint = remote_remove_breakpoint;
  remote_async_ops.to_can_use_hw_breakpoint = remote_check_watch_resources;
  remote_async_ops.to_insert_hw_breakpoint = remote_insert_hw_breakpoint;
  remote_async_ops.to_remove_hw_breakpoint = remote_remove_hw_breakpoint;
  remote_async_ops.to_insert_watchpoint = remote_insert_watchpoint;
  remote_async_ops.to_remove_watchpoint = remote_remove_watchpoint;
  remote_async_ops.to_stopped_by_watchpoint = remote_stopped_by_watchpoint;
  remote_async_ops.to_stopped_data_address = remote_stopped_data_address;
  remote_async_ops.to_terminal_inferior = remote_async_terminal_inferior;
  remote_async_ops.to_terminal_ours = remote_async_terminal_ours;
  remote_async_ops.to_kill = remote_async_kill;
  remote_async_ops.to_load = generic_load;
  remote_async_ops.to_mourn_inferior = remote_async_mourn;
  remote_async_ops.to_thread_alive = remote_thread_alive;
  remote_async_ops.to_find_new_threads = remote_threads_info;
  remote_async_ops.to_pid_to_str = remote_pid_to_str;
  remote_async_ops.to_extra_thread_info = remote_threads_extra_info;
  remote_async_ops.to_stop = remote_stop;
  remote_async_ops.to_xfer_partial = remote_xfer_partial;
  remote_async_ops.to_rcmd = remote_rcmd;
  remote_async_ops.to_stratum = process_stratum;
  remote_async_ops.to_has_all_memory = 1;
  remote_async_ops.to_has_memory = 1;
  remote_async_ops.to_has_stack = 1;
  remote_async_ops.to_has_registers = 1;
  remote_async_ops.to_has_execution = 1;
  remote_async_ops.to_has_thread_control = tc_schedlock;	/* can lock scheduler */
  remote_async_ops.to_can_async_p = remote_can_async_p;
  remote_async_ops.to_is_async_p = remote_is_async_p;
  remote_async_ops.to_async = remote_async;
  remote_async_ops.to_async_mask_value = 1;
  remote_async_ops.to_magic = OPS_MAGIC;
  remote_async_ops.to_memory_map = remote_memory_map;
  remote_async_ops.to_flash_erase = remote_flash_erase;
  remote_async_ops.to_flash_done = remote_flash_done;
}

/* Set up the async extended remote vector by making a copy of the standard
   remote vector and adding to it.  */

static void
init_extended_async_remote_ops (void)
{
  extended_async_remote_ops = remote_async_ops;

  extended_async_remote_ops.to_shortname = "extended-async";
  extended_async_remote_ops.to_longname =
    "Extended remote serial target in async gdb-specific protocol";
  extended_async_remote_ops.to_doc =
    "Use a remote computer via a serial line, using an async gdb-specific protocol.\n\
Specify the serial device it is connected to (e.g. /dev/ttya).",
    extended_async_remote_ops.to_open = extended_remote_async_open;
  extended_async_remote_ops.to_create_inferior = extended_remote_async_create_inferior;
  extended_async_remote_ops.to_mourn_inferior = extended_remote_mourn;
}

static void
set_remote_cmd (char *args, int from_tty)
{
  help_list (remote_set_cmdlist, "set remote ", -1, gdb_stdout);
}

static void
show_remote_cmd (char *args, int from_tty)
{
  /* We can't just use cmd_show_list here, because we want to skip
     the redundant "show remote Z-packet" and the legacy aliases.  */
  struct cleanup *showlist_chain;
  struct cmd_list_element *list = remote_show_cmdlist;

  showlist_chain = make_cleanup_ui_out_tuple_begin_end (uiout, "showlist");
  for (; list != NULL; list = list->next)
    if (strcmp (list->name, "Z-packet") == 0)
      continue;
    else if (list->type == not_set_cmd)
      /* Alias commands are exactly like the original, except they
	 don't have the normal type.  */
      continue;
    else
      {
	struct cleanup *option_chain
	  = make_cleanup_ui_out_tuple_begin_end (uiout, "option");
	ui_out_field_string (uiout, "name", list->name);
	ui_out_text (uiout, ":  ");
	if (list->type == show_cmd)
	  do_setshow_command ((char *) NULL, from_tty, list);
	else
	  cmd_func (list, NULL, from_tty);
	/* Close the tuple.  */
	do_cleanups (option_chain);
      }

  /* Close the tuple.  */
  do_cleanups (showlist_chain);
}

static void
build_remote_gdbarch_data (void)
{
  remote_address_size = TARGET_ADDR_BIT;
}

/* Saved pointer to previous owner of the new_objfile event.  */
static void (*remote_new_objfile_chain) (struct objfile *);

/* Function to be called whenever a new objfile (shlib) is detected.  */
static void
remote_new_objfile (struct objfile *objfile)
{
  if (remote_desc != 0)		/* Have a remote connection.  */
    {
      remote_check_symbols (objfile);
    }
  /* Call predecessor on chain, if any.  */
  if (remote_new_objfile_chain)
    remote_new_objfile_chain (objfile);
}

void
_initialize_remote (void)
{
  struct remote_state *rs;

  /* architecture specific data */
  remote_gdbarch_data_handle =
    gdbarch_data_register_post_init (init_remote_state);

  /* Old tacky stuff.  NOTE: This comes after the remote protocol so
     that the remote protocol has been initialized.  */
  DEPRECATED_REGISTER_GDBARCH_SWAP (remote_address_size);
  deprecated_register_gdbarch_swap (NULL, 0, build_remote_gdbarch_data);

  /* Initialize the per-target state.  At the moment there is only one
     of these, not one per target.  Only one target is active at a
     time.  The default buffer size is unimportant; it will be expanded
     whenever a larger buffer is needed.  */
  rs = get_remote_state_raw ();
  rs->buf_size = 400;
  rs->buf = xmalloc (rs->buf_size);

  init_remote_ops ();
  add_target (&remote_ops);

  init_extended_remote_ops ();
  add_target (&extended_remote_ops);

  init_remote_async_ops ();
  add_target (&remote_async_ops);

  init_extended_async_remote_ops ();
  add_target (&extended_async_remote_ops);

  /* Hook into new objfile notification.  */
  remote_new_objfile_chain = deprecated_target_new_objfile_hook;
  deprecated_target_new_objfile_hook  = remote_new_objfile;

#if 0
  init_remote_threadtests ();
#endif

  /* set/show remote ...  */

  add_prefix_cmd ("remote", class_maintenance, set_remote_cmd, _("\
Remote protocol specific variables\n\
Configure various remote-protocol specific variables such as\n\
the packets being used"),
		  &remote_set_cmdlist, "set remote ",
		  0 /* allow-unknown */, &setlist);
  add_prefix_cmd ("remote", class_maintenance, show_remote_cmd, _("\
Remote protocol specific variables\n\
Configure various remote-protocol specific variables such as\n\
the packets being used"),
		  &remote_show_cmdlist, "show remote ",
		  0 /* allow-unknown */, &showlist);

  add_cmd ("compare-sections", class_obscure, compare_sections_command, _("\
Compare section data on target to the exec file.\n\
Argument is a single section name (default: all loaded sections)."),
	   &cmdlist);

  add_cmd ("packet", class_maintenance, packet_command, _("\
Send an arbitrary packet to a remote target.\n\
   maintenance packet TEXT\n\
If GDB is talking to an inferior via the GDB serial protocol, then\n\
this command sends the string TEXT to the inferior, and displays the\n\
response packet.  GDB supplies the initial `$' character, and the\n\
terminating `#' character and checksum."),
	   &maintenancelist);

  add_setshow_boolean_cmd ("remotebreak", no_class, &remote_break, _("\
Set whether to send break if interrupted."), _("\
Show whether to send break if interrupted."), _("\
If set, a break, instead of a cntrl-c, is sent to the remote target."),
			   NULL, NULL, /* FIXME: i18n: Whether to send break if interrupted is %s.  */
			   &setlist, &showlist);

  /* Install commands for configuring memory read/write packets.  */

  add_cmd ("remotewritesize", no_class, set_memory_write_packet_size, _("\
Set the maximum number of bytes per memory write packet (deprecated)."),
	   &setlist);
  add_cmd ("remotewritesize", no_class, show_memory_write_packet_size, _("\
Show the maximum number of bytes per memory write packet (deprecated)."),
	   &showlist);
  add_cmd ("memory-write-packet-size", no_class,
	   set_memory_write_packet_size, _("\
Set the maximum number of bytes per memory-write packet.\n\
Specify the number of bytes in a packet or 0 (zero) for the\n\
default packet size.  The actual limit is further reduced\n\
dependent on the target.  Specify ``fixed'' to disable the\n\
further restriction and ``limit'' to enable that restriction."),
	   &remote_set_cmdlist);
  add_cmd ("memory-read-packet-size", no_class,
	   set_memory_read_packet_size, _("\
Set the maximum number of bytes per memory-read packet.\n\
Specify the number of bytes in a packet or 0 (zero) for the\n\
default packet size.  The actual limit is further reduced\n\
dependent on the target.  Specify ``fixed'' to disable the\n\
further restriction and ``limit'' to enable that restriction."),
	   &remote_set_cmdlist);
  add_cmd ("memory-write-packet-size", no_class,
	   show_memory_write_packet_size,
	   _("Show the maximum number of bytes per memory-write packet."),
	   &remote_show_cmdlist);
  add_cmd ("memory-read-packet-size", no_class,
	   show_memory_read_packet_size,
	   _("Show the maximum number of bytes per memory-read packet."),
	   &remote_show_cmdlist);

  add_setshow_zinteger_cmd ("hardware-watchpoint-limit", no_class,
			    &remote_hw_watchpoint_limit, _("\
Set the maximum number of target hardware watchpoints."), _("\
Show the maximum number of target hardware watchpoints."), _("\
Specify a negative limit for unlimited."),
			    NULL, NULL, /* FIXME: i18n: The maximum number of target hardware watchpoints is %s.  */
			    &remote_set_cmdlist, &remote_show_cmdlist);
  add_setshow_zinteger_cmd ("hardware-breakpoint-limit", no_class,
			    &remote_hw_breakpoint_limit, _("\
Set the maximum number of target hardware breakpoints."), _("\
Show the maximum number of target hardware breakpoints."), _("\
Specify a negative limit for unlimited."),
			    NULL, NULL, /* FIXME: i18n: The maximum number of target hardware breakpoints is %s.  */
			    &remote_set_cmdlist, &remote_show_cmdlist);

  add_setshow_integer_cmd ("remoteaddresssize", class_obscure,
			   &remote_address_size, _("\
Set the maximum size of the address (in bits) in a memory packet."), _("\
Show the maximum size of the address (in bits) in a memory packet."), NULL,
			   NULL,
			   NULL, /* FIXME: i18n: */
			   &setlist, &showlist);

  add_packet_config_cmd (&remote_protocol_packets[PACKET_X],
			 "X", "binary-download", 1);

  add_packet_config_cmd (&remote_protocol_packets[PACKET_vCont],
			 "vCont", "verbose-resume", 0);

  add_packet_config_cmd (&remote_protocol_packets[PACKET_qSymbol],
			 "qSymbol", "symbol-lookup", 0);

  add_packet_config_cmd (&remote_protocol_packets[PACKET_P],
			 "P", "set-register", 1);

  add_packet_config_cmd (&remote_protocol_packets[PACKET_p],
			 "p", "fetch-register", 1);

  add_packet_config_cmd (&remote_protocol_packets[PACKET_Z0],
			 "Z0", "software-breakpoint", 0);

  add_packet_config_cmd (&remote_protocol_packets[PACKET_Z1],
			 "Z1", "hardware-breakpoint", 0);

  add_packet_config_cmd (&remote_protocol_packets[PACKET_Z2],
			 "Z2", "write-watchpoint", 0);

  add_packet_config_cmd (&remote_protocol_packets[PACKET_Z3],
			 "Z3", "read-watchpoint", 0);

  add_packet_config_cmd (&remote_protocol_packets[PACKET_Z4],
			 "Z4", "access-watchpoint", 0);

  add_packet_config_cmd (&remote_protocol_packets[PACKET_qXfer_auxv],
			 "qXfer:auxv:read", "read-aux-vector", 0);

  add_packet_config_cmd (&remote_protocol_packets[PACKET_qXfer_memory_map],
			 "qXfer:memory-map:read", "memory-map", 0);

  add_packet_config_cmd (&remote_protocol_packets[PACKET_qGetTLSAddr],
			 "qGetTLSAddr", "get-thread-local-storage-address",
			 0);

  add_packet_config_cmd (&remote_protocol_packets[PACKET_qSupported],
			 "qSupported", "supported-packets", 0);

  /* Keep the old ``set remote Z-packet ...'' working.  Each individual
     Z sub-packet has its own set and show commands, but users may
     have sets to this variable in their .gdbinit files (or in their
     documentation).  */
  add_setshow_auto_boolean_cmd ("Z-packet", class_obscure,
				&remote_Z_packet_detect, _("\
Set use of remote protocol `Z' packets"), _("\
Show use of remote protocol `Z' packets "), _("\
When set, GDB will attempt to use the remote breakpoint and watchpoint\n\
packets."),
				set_remote_protocol_Z_packet_cmd,
				show_remote_protocol_Z_packet_cmd, /* FIXME: i18n: Use of remote protocol `Z' packets is %s.  */
				&remote_set_cmdlist, &remote_show_cmdlist);

  /* Eventually initialize fileio.  See fileio.c */
  initialize_remote_fileio (remote_set_cmdlist, remote_show_cmdlist);
}