Initial creation of sourceware repositorygdb-4_18-branchpoint

1 files changed, 1003 insertions, 0 deletions

diff --git a/gdb/remote-sim.c b/gdb/remote-sim.c
new file mode 100644
index 0000000..e10fced
--- /dev/null
+++ b/gdb/remote-sim.c
@@ -0,0 +1,1003 @@
+/* Generic remote debugging interface for simulators.
+   Copyright 1993, 1994, 1996, 1997 Free Software Foundation, Inc.
+   Contributed by Cygnus Support.
+   Steve Chamberlain (sac@cygnus.com).
+
+This file is part of GDB.
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
+
+#include "defs.h"
+#include "inferior.h"
+#include "wait.h"
+#include "value.h"
+#include "gdb_string.h"
+#include <ctype.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <setjmp.h>
+#include <errno.h>
+#include "terminal.h"
+#include "target.h"
+#include "gdbcore.h"
+#include "callback.h"
+#include "remote-sim.h"
+#include "remote-utils.h"
+#include "command.h"
+
+/* Prototypes */
+
+static void dump_mem PARAMS ((char *buf, int len));
+
+static void init_callbacks PARAMS ((void));
+
+static void end_callbacks PARAMS ((void));
+
+static int gdb_os_write_stdout PARAMS ((host_callback *, const char *, int));
+
+static void gdb_os_flush_stdout PARAMS ((host_callback *));
+
+static int gdb_os_write_stderr PARAMS ((host_callback *, const char *, int));
+
+static void gdb_os_flush_stderr PARAMS ((host_callback *));
+
+static int gdb_os_poll_quit PARAMS ((host_callback *));
+
+/* printf_filtered is depreciated */
+static void gdb_os_printf_filtered PARAMS ((host_callback *, const char *, ...));
+
+static void gdb_os_vprintf_filtered PARAMS ((host_callback *, const char *, va_list));
+
+static void gdb_os_evprintf_filtered PARAMS ((host_callback *, const char *, va_list));
+
+static void gdb_os_error PARAMS ((host_callback *, const char *, ...));
+
+static void gdbsim_fetch_register PARAMS ((int regno));
+
+static void gdbsim_store_register PARAMS ((int regno));
+
+static void gdbsim_kill PARAMS ((void));
+
+static void gdbsim_load PARAMS ((char *prog, int fromtty));
+
+static void gdbsim_create_inferior PARAMS ((char *exec_file, char *args, char **env));
+
+static void gdbsim_open PARAMS ((char *args, int from_tty));
+
+static void gdbsim_close PARAMS ((int quitting));
+
+static void gdbsim_detach PARAMS ((char *args, int from_tty));
+
+static void gdbsim_resume PARAMS ((int pid, int step, enum target_signal siggnal));
+
+static int gdbsim_wait PARAMS ((int pid, struct target_waitstatus *status));
+
+static void gdbsim_prepare_to_store PARAMS ((void));
+
+static int gdbsim_xfer_inferior_memory PARAMS ((CORE_ADDR memaddr,
+						char *myaddr, int len,
+						int write,
+						struct target_ops *target));
+
+static void gdbsim_files_info PARAMS ((struct target_ops *target));
+
+static void gdbsim_mourn_inferior PARAMS ((void));
+
+static void gdbsim_stop PARAMS ((void));
+
+void simulator_command PARAMS ((char *args, int from_tty));
+
+/* Naming convention:
+
+   sim_* are the interface to the simulator (see remote-sim.h).
+   gdbsim_* are stuff which is internal to gdb.  */
+
+/* Forward data declarations */
+extern struct target_ops gdbsim_ops;
+
+static int program_loaded = 0;
+
+/* We must keep track of whether the simulator has been opened or not because
+   GDB can call a target's close routine twice, but sim_close doesn't allow
+   this.  We also need to record the result of sim_open so we can pass it
+   back to the other sim_foo routines.  */
+static SIM_DESC gdbsim_desc = 0;
+
+static void
+dump_mem (buf, len)
+     char *buf;
+     int len;
+{
+  if (len <= 8)
+    {
+      if (len == 8 || len == 4)
+	{
+	  long l[2];
+	  memcpy (l, buf, len);
+	  printf_filtered ("\t0x%x", l[0]);
+	  printf_filtered (len == 8 ? " 0x%x\n" : "\n", l[1]);
+	}
+      else
+	{
+	  int i;
+	  printf_filtered ("\t");
+	  for (i = 0; i < len; i++)
+	    printf_filtered ("0x%x ", buf[i]);
+	  printf_filtered ("\n");
+	}
+    }
+}
+
+static host_callback gdb_callback;
+static int callbacks_initialized = 0;
+
+/* Initialize gdb_callback.  */
+
+static void
+init_callbacks ()
+{
+  if (! callbacks_initialized)
+    {
+      gdb_callback = default_callback;
+      gdb_callback.init (&gdb_callback);
+      gdb_callback.write_stdout = gdb_os_write_stdout;
+      gdb_callback.flush_stdout = gdb_os_flush_stdout;
+      gdb_callback.write_stderr = gdb_os_write_stderr;
+      gdb_callback.flush_stderr = gdb_os_flush_stderr;
+      gdb_callback.printf_filtered = gdb_os_printf_filtered;
+      gdb_callback.vprintf_filtered = gdb_os_vprintf_filtered;
+      gdb_callback.evprintf_filtered = gdb_os_evprintf_filtered;
+      gdb_callback.error = gdb_os_error;
+      gdb_callback.poll_quit = gdb_os_poll_quit;
+      gdb_callback.magic = HOST_CALLBACK_MAGIC;
+      callbacks_initialized = 1;
+    }
+}
+
+/* Release callbacks (free resources used by them).  */
+
+static void
+end_callbacks ()
+{
+  if (callbacks_initialized)
+    {
+      gdb_callback.shutdown (&gdb_callback);
+      callbacks_initialized = 0;
+    }
+}
+
+/* GDB version of os_write_stdout callback.  */
+
+static int 
+gdb_os_write_stdout (p, buf, len)
+     host_callback *p;
+     const char *buf;
+     int len;
+{
+  int i;
+  char b[2];
+
+  for (i = 0; i < len; i++) 
+    {
+      b[0] = buf[i];
+      b[1] = 0;
+      if (target_output_hook)
+	target_output_hook (b);
+      else
+	fputs_filtered (b, gdb_stdout);
+    }
+  return len;
+}
+
+/* GDB version of os_flush_stdout callback.  */
+
+static void
+gdb_os_flush_stdout (p)
+     host_callback *p;
+{
+  gdb_flush (gdb_stdout);
+}
+
+/* GDB version of os_write_stderr callback.  */
+
+static int 
+gdb_os_write_stderr (p, buf, len)
+     host_callback *p;
+     const char *buf;
+     int len;
+{
+  int i;
+  char b[2];
+
+  for (i = 0; i < len; i++) 
+    {
+      b[0] = buf[i];
+      b[1] = 0;
+      if (target_output_hook)
+	target_output_hook (b);
+      else
+	fputs_filtered (b, gdb_stderr);
+    }
+  return len;
+}
+
+/* GDB version of os_flush_stderr callback.  */
+
+static void
+gdb_os_flush_stderr (p)
+     host_callback *p;
+{
+  gdb_flush (gdb_stderr);
+}
+
+/* GDB version of printf_filtered callback.  */
+
+/* VARARGS */
+static void
+#ifdef ANSI_PROTOTYPES
+gdb_os_printf_filtered (host_callback *p, const char *format, ...)
+#else
+gdb_os_printf_filtered (p, va_alist)
+     host_callback *p;
+     va_dcl
+#endif
+{
+  va_list args;
+#ifdef ANSI_PROTOTYPES
+  va_start (args, format);
+#else
+  char *format;
+
+  va_start (args);
+  format = va_arg (args, char *);
+#endif
+
+  vfprintf_filtered (gdb_stdout, format, args);
+
+  va_end (args);
+}
+
+/* GDB version of error vprintf_filtered.  */
+
+/* VARARGS */
+static void
+#ifdef ANSI_PROTOTYPES
+gdb_os_vprintf_filtered (host_callback *p, const char *format, va_list ap)
+#else
+gdb_os_vprintf_filtered (p, format, ap)
+     host_callback *p;
+     char *format;
+     va_list ap;
+#endif
+{
+  vfprintf_filtered (gdb_stdout, format, ap);
+}
+
+/* GDB version of error evprintf_filtered.  */
+
+/* VARARGS */
+static void
+#ifdef ANSI_PROTOTYPES
+gdb_os_evprintf_filtered (host_callback *p, const char *format, va_list ap)
+#else
+gdb_os_evprintf_filtered (p, format, ap)
+     host_callback *p;
+     char *format;
+     va_list ap;
+#endif
+{
+  vfprintf_filtered (gdb_stderr, format, ap);
+}
+
+/* GDB version of error callback.  */
+
+/* VARARGS */
+static void
+#ifdef ANSI_PROTOTYPES
+gdb_os_error (host_callback *p, const char *format, ...)
+#else
+gdb_os_error (p, va_alist)
+     host_callback *p;
+     va_dcl
+#endif
+{
+  if (error_hook)
+    (*error_hook) ();
+  else 
+    {
+      va_list args;
+#ifdef ANSI_PROTOTYPES
+      va_start (args, format);
+#else
+      char *format;
+
+      va_start (args);
+      format = va_arg (args, char *);
+#endif
+
+      error_begin ();
+      vfprintf_filtered (gdb_stderr, format, args);
+      fprintf_filtered (gdb_stderr, "\n");
+      va_end (args);
+      return_to_top_level (RETURN_ERROR);
+    }
+}
+
+static void
+gdbsim_fetch_register (regno)
+     int regno;
+{
+  static int warn_user = 1;
+  if (regno == -1) 
+    {
+      for (regno = 0; regno < NUM_REGS; regno++)
+	gdbsim_fetch_register (regno);
+    }
+  else if (REGISTER_NAME (regno) != NULL && *REGISTER_NAME (regno) != '\0')
+    {
+      char buf[MAX_REGISTER_RAW_SIZE];
+      int nr_bytes = sim_fetch_register (gdbsim_desc, regno, buf, REGISTER_RAW_SIZE (regno));
+      if (nr_bytes == 0)
+	/* register not applicable, supply zero's */
+	memset (buf, 0, MAX_REGISTER_RAW_SIZE);
+      else if (nr_bytes > 0 && nr_bytes != REGISTER_RAW_SIZE (regno)
+	       && warn_user)
+	{
+	  printf_unfiltered ("Size of register %s (%d) incorrect (%d instead of %d))",
+			     REGISTER_NAME (regno), regno,
+			     nr_bytes, REGISTER_RAW_SIZE (regno));
+	  warn_user = 0;
+	}
+      supply_register (regno, buf);
+      if (sr_get_debug ())
+	{
+	  printf_filtered ("gdbsim_fetch_register: %d", regno);
+	  /* FIXME: We could print something more intelligible.  */
+	  dump_mem (buf, REGISTER_RAW_SIZE (regno));
+	}
+    }
+}
+
+
+static void
+gdbsim_store_register (regno)
+     int regno;
+{
+  if (regno  == -1) 
+    {
+      for (regno = 0; regno < NUM_REGS; regno++)
+	gdbsim_store_register (regno);
+    }
+  else if (REGISTER_NAME (regno) != NULL && *REGISTER_NAME (regno) != '\0')
+    {
+      char tmp[MAX_REGISTER_RAW_SIZE];
+      int nr_bytes;
+      read_register_gen (regno, tmp);
+      nr_bytes = sim_store_register (gdbsim_desc, regno, tmp, REGISTER_RAW_SIZE (regno));
+      if (nr_bytes > 0 && nr_bytes != REGISTER_RAW_SIZE (regno))
+	fatal ("Register size different to expected");
+      if (sr_get_debug ())
+	{
+	  printf_filtered ("gdbsim_store_register: %d", regno);
+	  /* FIXME: We could print something more intelligible.  */
+	  dump_mem (tmp, REGISTER_RAW_SIZE (regno));
+	}
+    }
+}
+
+/* Kill the running program.  This may involve closing any open files
+   and releasing other resources acquired by the simulated program.  */
+
+static void
+gdbsim_kill ()
+{
+  if (sr_get_debug ())
+    printf_filtered ("gdbsim_kill\n");
+
+  /* There is no need to `kill' running simulator - the simulator is
+     not running */
+  inferior_pid = 0;
+}
+
+/* Load an executable file into the target process.  This is expected to
+   not only bring new code into the target process, but also to update
+   GDB's symbol tables to match.  */
+
+static void
+gdbsim_load (prog, fromtty)
+     char *prog;
+     int fromtty;
+{
+  if (sr_get_debug ())
+    printf_filtered ("gdbsim_load: prog \"%s\"\n", prog);
+
+  inferior_pid = 0;
+
+  /* FIXME: We will print two messages on error.
+     Need error to either not print anything if passed NULL or need
+     another routine that doesn't take any arguments.  */
+  if (sim_load (gdbsim_desc, prog, NULL, fromtty) == SIM_RC_FAIL)
+    error ("unable to load program");
+
+  /* FIXME: If a load command should reset the targets registers then
+     a call to sim_create_inferior() should go here. */
+
+  program_loaded = 1;
+}
+
+
+/* Start an inferior process and set inferior_pid to its pid.
+   EXEC_FILE is the file to run.
+   ARGS is a string containing the arguments to the program.
+   ENV is the environment vector to pass.  Errors reported with error().
+   On VxWorks and various standalone systems, we ignore exec_file.  */
+/* This is called not only when we first attach, but also when the
+   user types "run" after having attached.  */
+
+static void
+gdbsim_create_inferior (exec_file, args, env)
+     char *exec_file;
+     char *args;
+     char **env;
+{
+  int len;
+  char *arg_buf,**argv;
+
+  if (exec_file == 0 || exec_bfd == 0)
+    warning ("No executable file specified.");
+  if (! program_loaded)
+    warning ("No program loaded.");
+
+  if (sr_get_debug ())
+    printf_filtered ("gdbsim_create_inferior: exec_file \"%s\", args \"%s\"\n",
+		     (exec_file ? exec_file: "(NULL)"),
+		     args);
+
+  gdbsim_kill ();	 
+  remove_breakpoints ();
+  init_wait_for_inferior ();
+
+  if (exec_file != NULL)
+    {
+      len = strlen (exec_file) + 1 + strlen (args) + 1 + /*slop*/ 10;
+      arg_buf = (char *) alloca (len);
+      arg_buf[0] = '\0';
+      strcat (arg_buf, exec_file);
+      strcat (arg_buf, " ");
+      strcat (arg_buf, args);
+      argv = buildargv (arg_buf);
+      make_cleanup ((make_cleanup_func) freeargv, argv);
+    }
+  else
+    argv = NULL;
+  sim_create_inferior (gdbsim_desc, exec_bfd, argv, env);
+
+  inferior_pid = 42;
+  insert_breakpoints (); /* Needed to get correct instruction in cache */
+
+  clear_proceed_status ();
+
+  /* NB: Entry point already set by sim_create_inferior. */
+  proceed ((CORE_ADDR)-1, TARGET_SIGNAL_DEFAULT, 0);
+}
+
+/* The open routine takes the rest of the parameters from the command,
+   and (if successful) pushes a new target onto the stack.
+   Targets should supply this routine, if only to provide an error message.  */
+/* Called when selecting the simulator. EG: (gdb) target sim name.  */
+
+static void
+gdbsim_open (args, from_tty)
+     char *args;
+     int from_tty;
+{
+  int len;
+  char *arg_buf;
+  char **argv;
+
+  if (sr_get_debug ())
+    printf_filtered ("gdbsim_open: args \"%s\"\n", args ? args : "(null)");
+
+  /* Remove current simulator if one exists.  Only do this if the simulator
+     has been opened because sim_close requires it.
+     This is important because the call to push_target below will cause
+     sim_close to be called if the simulator is already open, but push_target
+     is called after sim_open!  We can't move the call to push_target before
+     the call to sim_open because sim_open may invoke `error'.  */
+  if (gdbsim_desc != NULL)
+    unpush_target (&gdbsim_ops);
+
+  len = (7 + 1 /* gdbsim */
+	 + strlen (" -E little")
+	 + strlen (" --architecture=xxxxxxxxxx")
+	 + (args ? strlen (args) : 0)
+	 + 50) /* slack */;
+  arg_buf = (char *) alloca (len);
+  strcpy (arg_buf, "gdbsim"); /* 7 */
+  /* Specify the byte order for the target when it is both selectable
+     and explicitly specified by the user (not auto detected). */
+  if (TARGET_BYTE_ORDER_SELECTABLE_P
+      && !TARGET_BYTE_ORDER_AUTO)
+    {
+      switch (TARGET_BYTE_ORDER)
+	{
+	case BIG_ENDIAN:
+	  strcat (arg_buf, " -E big");
+	  break;
+	case LITTLE_ENDIAN:
+	  strcat (arg_buf, " -E little");
+	  break;
+	default:
+	  fatal ("Value of TARGET_BYTE_ORDER unknown");
+	}
+    }
+  /* Specify the architecture of the target when it has been
+     explicitly specified */
+  if (!TARGET_ARCHITECTURE_AUTO)
+    {
+      strcat (arg_buf, " --architecture=");
+      strcat (arg_buf, TARGET_ARCHITECTURE->printable_name);
+    }
+  /* finally, any explicit args */
+  if (args)
+    {
+      strcat (arg_buf, " "); /* 1 */
+      strcat (arg_buf, args);
+    }
+  argv = buildargv (arg_buf);
+  if (argv == NULL)
+    error ("Insufficient memory available to allocate simulator arg list.");
+  make_cleanup ((make_cleanup_func) freeargv, argv);
+
+  init_callbacks ();
+  gdbsim_desc = sim_open (SIM_OPEN_DEBUG, &gdb_callback, exec_bfd, argv);
+
+  if (gdbsim_desc == 0)
+    error ("unable to create simulator instance");
+
+  push_target (&gdbsim_ops);
+  target_fetch_registers (-1);
+  printf_filtered ("Connected to the simulator.\n");
+}
+
+/* Does whatever cleanup is required for a target that we are no longer
+   going to be calling.  Argument says whether we are quitting gdb and
+   should not get hung in case of errors, or whether we want a clean
+   termination even if it takes a while.  This routine is automatically
+   always called just before a routine is popped off the target stack.
+   Closing file descriptors and freeing memory are typical things it should
+   do.  */
+/* Close out all files and local state before this target loses control. */
+
+static void
+gdbsim_close (quitting)
+     int quitting;
+{
+  if (sr_get_debug ())
+    printf_filtered ("gdbsim_close: quitting %d\n", quitting);
+
+  program_loaded = 0;
+
+  if (gdbsim_desc != NULL)
+    {
+      sim_close (gdbsim_desc, quitting);
+      gdbsim_desc = NULL;
+    }
+
+  end_callbacks ();
+}
+
+/* Takes a program previously attached to and detaches it.
+   The program may resume execution (some targets do, some don't) and will
+   no longer stop on signals, etc.  We better not have left any breakpoints
+   in the program or it'll die when it hits one.  ARGS is arguments
+   typed by the user (e.g. a signal to send the process).  FROM_TTY
+   says whether to be verbose or not.  */
+/* Terminate the open connection to the remote debugger.
+   Use this when you want to detach and do something else with your gdb.  */
+
+static void
+gdbsim_detach (args,from_tty)
+     char *args;
+     int from_tty;
+{
+  if (sr_get_debug ())
+    printf_filtered ("gdbsim_detach: args \"%s\"\n", args);
+
+  pop_target ();		/* calls gdbsim_close to do the real work */
+  if (from_tty)
+    printf_filtered ("Ending simulator %s debugging\n", target_shortname);
+}
+ 
+/* Resume execution of the target process.  STEP says whether to single-step
+   or to run free; SIGGNAL is the signal value (e.g. SIGINT) to be given
+   to the target, or zero for no signal.  */
+
+static enum target_signal resume_siggnal;
+static int resume_step;
+
+static void
+gdbsim_resume (pid, step, siggnal)
+     int pid, step;
+     enum target_signal siggnal;
+{
+  if (inferior_pid != 42)
+    error ("The program is not being run.");
+
+  if (sr_get_debug ())
+    printf_filtered ("gdbsim_resume: step %d, signal %d\n", step, siggnal);
+
+  resume_siggnal = siggnal;
+  resume_step = step;
+}
+
+/* Notify the simulator of an asynchronous request to stop.
+   
+   The simulator shall ensure that the stop request is eventually
+   delivered to the simulator.  If the call is made while the
+   simulator is not running then the stop request is processed when
+   the simulator is next resumed.
+
+   For simulators that do not support this operation, just abort */
+
+static void
+gdbsim_stop ()
+{
+  if (! sim_stop (gdbsim_desc))
+    {
+      quit ();
+    }
+}
+
+/* GDB version of os_poll_quit callback.
+   Taken from gdb/util.c - should be in a library */
+
+static int
+gdb_os_poll_quit (p)
+     host_callback *p;
+{
+  notice_quit ();
+  if (quit_flag) /* gdb's idea of quit */
+    {
+      quit_flag = 0; /* we've stolen it */
+      return 1;
+    }
+  else if (immediate_quit)
+    {
+      return 1;
+    }
+  return 0;
+}
+
+/* Wait for inferior process to do something.  Return pid of child,
+   or -1 in case of error; store status through argument pointer STATUS,
+   just as `wait' would. */
+
+static void
+gdbsim_cntrl_c (signo)
+     int signo;
+{
+  gdbsim_stop ();
+}
+
+static int
+gdbsim_wait (pid, status)
+     int pid;
+     struct target_waitstatus *status;
+{
+  static RETSIGTYPE (*prev_sigint) ();
+  int sigrc = 0;
+  enum sim_stop reason = sim_running;
+
+  if (sr_get_debug ())
+    printf_filtered ("gdbsim_wait\n");
+
+#if defined (HAVE_SIGACTION) && defined (SA_RESTART)
+  {
+    struct sigaction sa, osa;
+    sa.sa_handler = gdbsim_cntrl_c;
+    sigemptyset (&sa.sa_mask);
+    sa.sa_flags = 0;
+    sigaction (SIGINT, &sa, &osa);
+    prev_sigint = osa.sa_handler;
+  }
+#else
+  prev_sigint = signal (SIGINT, gdbsim_cntrl_c);
+#endif
+  sim_resume (gdbsim_desc, resume_step,
+	      target_signal_to_host (resume_siggnal));
+  signal (SIGINT, prev_sigint);
+  resume_step = 0;
+
+  sim_stop_reason (gdbsim_desc, &reason, &sigrc);
+
+  switch (reason)
+    {
+    case sim_exited:
+      status->kind = TARGET_WAITKIND_EXITED;
+      status->value.integer = sigrc;
+      break;
+    case sim_stopped:
+      switch (sigrc)
+	{
+	case SIGABRT:
+	  quit ();
+	  break;
+	case SIGINT:
+	case SIGTRAP:
+	default:
+	  status->kind = TARGET_WAITKIND_STOPPED;
+	  /* The signal in sigrc is a host signal.  That probably
+	     should be fixed.  */
+	  status->value.sig = target_signal_from_host (sigrc);
+	  break;
+	}
+      break;
+    case sim_signalled:
+      status->kind = TARGET_WAITKIND_SIGNALLED;
+      /* The signal in sigrc is a host signal.  That probably
+	 should be fixed.  */
+      status->value.sig = target_signal_from_host (sigrc);
+      break;
+    case sim_running:
+    case sim_polling:
+      /* FIXME: Is this correct? */
+      break;
+    }
+
+  return inferior_pid;
+}
+
+/* Get ready to modify the registers array.  On machines which store
+   individual registers, this doesn't need to do anything.  On machines
+   which store all the registers in one fell swoop, this makes sure
+   that registers contains all the registers from the program being
+   debugged.  */
+
+static void
+gdbsim_prepare_to_store ()
+{
+  /* Do nothing, since we can store individual regs */
+}
+
+static int
+gdbsim_xfer_inferior_memory (memaddr, myaddr, len, write, target)
+     CORE_ADDR memaddr;
+     char *myaddr;
+     int len;
+     int write;
+     struct target_ops *target;			/* ignored */
+{
+  if (! program_loaded)
+    error ("No program loaded.");
+
+  if (sr_get_debug ())
+    {
+      printf_filtered ("gdbsim_xfer_inferior_memory: myaddr 0x%x, memaddr 0x%x, len %d, write %d\n",
+		       myaddr, memaddr, len, write);
+      if (sr_get_debug () && write)
+	dump_mem(myaddr, len);
+    }
+
+  if (write)
+    {
+      len = sim_write (gdbsim_desc, memaddr, myaddr, len);
+    }
+  else 
+    {
+      len = sim_read (gdbsim_desc, memaddr, myaddr, len);
+      if (sr_get_debug () && len > 0)
+	dump_mem(myaddr, len);
+    } 
+  return len;
+}
+
+static void
+gdbsim_files_info (target)
+     struct target_ops *target;
+{
+  char *file = "nothing";
+
+  if (exec_bfd)
+    file = bfd_get_filename (exec_bfd);
+
+  if (sr_get_debug ())
+    printf_filtered ("gdbsim_files_info: file \"%s\"\n", file);
+
+  if (exec_bfd)
+    {
+      printf_filtered ("\tAttached to %s running program %s\n",
+		       target_shortname, file);
+      sim_info (gdbsim_desc, 0);
+    }
+}
+
+/* Clear the simulator's notion of what the break points are.  */
+
+static void
+gdbsim_mourn_inferior () 
+{ 
+  if (sr_get_debug ())
+    printf_filtered ("gdbsim_mourn_inferior:\n");
+
+  remove_breakpoints ();
+  generic_mourn_inferior ();
+}
+
+static int
+gdbsim_insert_breakpoint (addr, contents_cache)
+     CORE_ADDR addr;
+     char *contents_cache;
+{
+#ifdef SIM_HAS_BREAKPOINTS
+  SIM_RC retcode;
+
+  retcode = sim_set_breakpoint (gdbsim_desc, addr);
+
+  switch (retcode)
+    {
+    case SIM_RC_OK:
+      return 0;
+    case SIM_RC_INSUFFICIENT_RESOURCES:
+      return ENOMEM;
+    default:
+      return EIO;
+    }
+#else
+  return memory_insert_breakpoint (addr, contents_cache);
+#endif
+}
+
+static int
+gdbsim_remove_breakpoint (addr, contents_cache)
+     CORE_ADDR addr;
+     char *contents_cache;
+{
+#ifdef SIM_HAS_BREAKPOINTS
+  SIM_RC retcode;
+
+  retcode = sim_clear_breakpoint (gdbsim_desc, addr);
+
+  switch (retcode)
+    {
+    case SIM_RC_OK:
+    case SIM_RC_UNKNOWN_BREAKPOINT:
+      return 0;
+    case SIM_RC_INSUFFICIENT_RESOURCES:
+      return ENOMEM;
+    default:
+      return EIO;
+    }
+#else
+  return memory_remove_breakpoint (addr, contents_cache);
+#endif
+}
+
+/* Pass the command argument through to the simulator verbatim.  The
+   simulator must do any command interpretation work.  */
+
+void
+simulator_command (args, from_tty)
+     char *args;
+     int from_tty;
+{
+  if (gdbsim_desc == NULL)
+    {
+
+      /* PREVIOUSLY: The user may give a command before the simulator
+         is opened. [...] (??? assuming of course one wishes to
+         continue to allow commands to be sent to unopened simulators,
+         which isn't entirely unreasonable). */
+
+      /* The simulator is a builtin abstraction of a remote target.
+         Consistent with that model, access to the simulator, via sim
+         commands, is restricted to the period when the channel to the
+         simulator is open. */
+
+      error ("Not connected to the simulator target");
+    }
+
+  sim_do_command (gdbsim_desc, args);
+
+  /* Invalidate the register cache, in case the simulator command does
+     something funny. */
+  registers_changed (); 
+}
+
+/* Define the target subroutine names */
+
+struct target_ops gdbsim_ops ;
+
+static void 
+init_gdbsim_ops(void)
+{
+  gdbsim_ops.to_shortname =   "sim";		
+  gdbsim_ops.to_longname =   "simulator";		
+  gdbsim_ops.to_doc =   "Use the compiled-in simulator.";  
+  gdbsim_ops.to_open =   gdbsim_open;		
+  gdbsim_ops.to_close =   gdbsim_close;		
+  gdbsim_ops.to_attach =   NULL;
+  gdbsim_ops.to_post_attach = NULL;  
+  gdbsim_ops.to_require_attach = NULL;	
+  gdbsim_ops.to_detach =   gdbsim_detach;
+  gdbsim_ops.to_require_detach = NULL;	
+  gdbsim_ops.to_resume =   gdbsim_resume;	
+  gdbsim_ops.to_wait  =   gdbsim_wait;
+  gdbsim_ops.to_post_wait = NULL;		
+  gdbsim_ops.to_fetch_registers  =   gdbsim_fetch_register;
+  gdbsim_ops.to_store_registers  =   gdbsim_store_register;
+  gdbsim_ops.to_prepare_to_store =   gdbsim_prepare_to_store;
+  gdbsim_ops.to_xfer_memory  =   gdbsim_xfer_inferior_memory;
+  gdbsim_ops.to_files_info  =   gdbsim_files_info;	
+  gdbsim_ops.to_insert_breakpoint =   gdbsim_insert_breakpoint;
+  gdbsim_ops.to_remove_breakpoint =   gdbsim_remove_breakpoint;
+  gdbsim_ops.to_terminal_init  =   NULL;		
+  gdbsim_ops.to_terminal_inferior =   NULL;		
+  gdbsim_ops.to_terminal_ours_for_output =   NULL;
+  gdbsim_ops.to_terminal_ours  =   NULL;
+  gdbsim_ops.to_terminal_info  =   NULL;
+  gdbsim_ops.to_kill  =   gdbsim_kill;	
+  gdbsim_ops.to_load  =   gdbsim_load;	
+  gdbsim_ops.to_lookup_symbol =   NULL;	
+  gdbsim_ops.to_create_inferior =   gdbsim_create_inferior;
+  gdbsim_ops.to_post_startup_inferior = NULL;
+  gdbsim_ops.to_acknowledge_created_inferior = NULL;
+  gdbsim_ops.to_clone_and_follow_inferior = NULL;
+  gdbsim_ops.to_post_follow_inferior_by_clone = NULL;
+  gdbsim_ops.to_insert_fork_catchpoint = NULL;
+  gdbsim_ops.to_remove_fork_catchpoint = NULL;
+  gdbsim_ops.to_insert_vfork_catchpoint = NULL;
+  gdbsim_ops.to_remove_vfork_catchpoint = NULL;
+  gdbsim_ops.to_has_forked = NULL;
+  gdbsim_ops.to_has_vforked = NULL;
+  gdbsim_ops.to_can_follow_vfork_prior_to_exec = NULL;
+  gdbsim_ops.to_post_follow_vfork = NULL;
+  gdbsim_ops.to_insert_exec_catchpoint = NULL;
+  gdbsim_ops.to_remove_exec_catchpoint = NULL;
+  gdbsim_ops.to_has_execd = NULL;
+  gdbsim_ops.to_reported_exec_events_per_exec_call = NULL;
+  gdbsim_ops.to_has_exited = NULL;
+  gdbsim_ops.to_mourn_inferior =   gdbsim_mourn_inferior;
+  gdbsim_ops.to_can_run  =   0;			
+  gdbsim_ops.to_notice_signals =   0;		
+  gdbsim_ops.to_thread_alive  =   0;		
+  gdbsim_ops.to_stop  =   gdbsim_stop;
+  gdbsim_ops.to_pid_to_exec_file = NULL;	
+  gdbsim_ops.to_core_file_to_sym_file = NULL;	
+  gdbsim_ops.to_stratum =   process_stratum;	
+  gdbsim_ops.DONT_USE =   NULL;		
+  gdbsim_ops.to_has_all_memory =   1;	
+  gdbsim_ops.to_has_memory =   1;	
+  gdbsim_ops.to_has_stack =   1;	
+  gdbsim_ops.to_has_registers =   1;	
+  gdbsim_ops.to_has_execution =   1;	
+  gdbsim_ops.to_sections =   NULL;	
+  gdbsim_ops.to_sections_end =   NULL;	
+  gdbsim_ops.to_magic =   OPS_MAGIC;	
+
+#ifdef TARGET_REDEFINE_DEFAULT_OPS
+  TARGET_REDEFINE_DEFAULT_OPS (&gdbsim_ops);
+#endif
+}
+
+void
+_initialize_remote_sim ()
+{
+  init_gdbsim_ops() ;
+  add_target (&gdbsim_ops);
+
+  add_com ("sim <command>", class_obscure, simulator_command,
+	   "Send a command to the simulator."); 
+}