Initial import of gdbserver FreeBSD support

svn path=/cvs2svn/branches/TRAINA/; revision=25149

gnu/usr.bin/binutils/gdbserver/Makefile

@@ -0,0 +1,17 @@
+#	$Id: Makefile,v 1.13.2.1 1997/02/02 20:46:32 joerg Exp $
+
+GDBDIR=	${.CURDIR}/../../../../contrib/gdb
+.PATH:	${GDBDIR}/gdb/gdbserver
+.PATH:	${GDBDIR}/gdb
+.PATH:	${GDBDIR}/opcodes
+
+PROG=	gdbserver
+BINDIR=	/usr/bin
+
+SRCS=	remote-utils.c utils.c server.c
+SRCS+=	low-fbsd.c
+
+CFLAGS+=-I${.CURDIR}/../gdb -I${.CURDIR}/../bfd -I${GDBDIR}/gdb -I${GDBDIR}/bfd
+CFLAGS+=-DNO_MMALLOC
+
+.include <bsd.prog.mk>

gnu/usr.bin/binutils/gdbserver/low-fbsd.c

@@ -0,0 +1,433 @@
+/* Low level interface to ptrace, for the remote server for GDB.
+   Copyright (C) 1995 Free Software Foundation, Inc.
+
+This file is part of GDB.
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
+
+#include "defs.h"
+#include <sys/wait.h>
+#include "frame.h"
+#include "inferior.h"
+
+#include <stdio.h>
+#include <sys/param.h>
+#include <sys/dir.h>
+#include <sys/user.h>
+#include <signal.h>
+#include <sys/ioctl.h>
+#include <sgtty.h>
+#include <fcntl.h>
+
+/***************Begin MY defs*********************/
+int quit_flag = 0;
+char registers[REGISTER_BYTES];
+
+/* Index within `registers' of the first byte of the space for
+   register N.  */
+
+
+char buf2[MAX_REGISTER_RAW_SIZE];
+/***************End MY defs*********************/
+
+#include <sys/ptrace.h>
+#include <machine/reg.h>
+
+extern char **environ;
+extern int inferior_pid;
+void quit (), perror_with_name ();
+int query ();
+
+/* Start an inferior process and returns its pid.
+   ALLARGS is a vector of program-name and args.
+   ENV is the environment vector to pass.  */
+
+int
+create_inferior (program, allargs)
+     char *program;
+     char **allargs;
+{
+  int pid;
+
+  pid = fork ();
+  if (pid < 0)
+    perror_with_name ("fork");
+
+  if (pid == 0)
+    {
+      ptrace (PT_TRACE_ME, 0, 0, 0);
+
+      execv (program, allargs);
+
+      fprintf (stderr, "Cannot exec %s: %s.\n", program, strerror(errno));
+      fflush (stderr);
+      _exit (0177);
+    }
+
+  return pid;
+}
+
+/* Kill the inferior process.  Make us have no inferior.  */
+
+void
+kill_inferior ()
+{
+  if (inferior_pid == 0)
+    return;
+  ptrace (PT_KILL, inferior_pid, 0, 0);
+  wait (0);
+  /*************inferior_died ();****VK**************/
+}
+
+/* Return nonzero if the given thread is still alive.  */
+int
+mythread_alive (pid)
+     int pid;
+{
+  return 1;
+}
+
+/* Wait for process, returns status */
+
+unsigned char
+mywait (status)
+     char *status;
+{
+  int pid;
+  int w;
+
+  pid = wait (&w);
+  if (pid != inferior_pid)
+    perror_with_name ("wait");
+
+  if (WIFEXITED (w))
+    {
+      fprintf (stderr, "\nChild exited with retcode = %x \n", WEXITSTATUS (w));
+      *status = 'W';
+      return ((unsigned char) WEXITSTATUS (w));
+    }
+  else if (!WIFSTOPPED (w))
+    {
+      fprintf (stderr, "\nChild terminated with signal = %x \n", WTERMSIG (w));
+      *status = 'X';
+      return ((unsigned char) WTERMSIG (w));
+    }
+
+  fetch_inferior_registers (0);
+
+  *status = 'T';
+  return ((unsigned char) WSTOPSIG (w));
+}
+
+/* Resume execution of the inferior process.
+   If STEP is nonzero, single-step it.
+   If SIGNAL is nonzero, give it that signal.  */
+
+void
+myresume (step, signal)
+     int step;
+     int signal;
+{
+  errno = 0;
+  ptrace (step ? PT_STEP : PT_CONTINUE, inferior_pid,
+	  (PTRACE_ARG3_TYPE) 1, signal);
+  if (errno)
+    perror_with_name ("ptrace");
+}
+
+
+#if !defined (offsetof)
+#define offsetof(TYPE, MEMBER) ((unsigned long) &((TYPE *)0)->MEMBER)
+#endif
+
+/* U_REGS_OFFSET is the offset of the registers within the u area.  */
+#if !defined (U_REGS_OFFSET)
+#define U_REGS_OFFSET \
+  ptrace (PT_READ_U, inferior_pid, \
+          (PTRACE_ARG3_TYPE) (offsetof (struct user, u_ar0)), 0) \
+    - KERNEL_U_ADDR
+#endif
+
+unsigned int
+register_addr (regno, blockend)
+     int regno;
+     int blockend;
+{
+  int addr;
+
+  if (regno < 0 || regno >= ARCH_NUM_REGS)
+    error ("Invalid register number %d.", regno);
+
+  REGISTER_U_ADDR (addr, blockend, regno);
+
+  return addr;
+}
+
+/* Fetch one register.  */
+
+static void
+fetch_register (regno)
+     int regno;
+{
+  register unsigned int regaddr;
+  char buf[MAX_REGISTER_RAW_SIZE];
+  register int i;
+
+  /* Offset of registers within the u area.  */
+  unsigned int offset;
+
+  offset = U_REGS_OFFSET;
+
+  regaddr = register_addr (regno, offset);
+  for (i = 0; i < REGISTER_RAW_SIZE (regno); i += sizeof (int))
+    {
+      errno = 0;
+      *(int *) &registers[ regno * sizeof(int) + i] = 
+	  ptrace (PT_READ_U, inferior_pid, (PTRACE_ARG3_TYPE) regaddr, 0);
+      regaddr += sizeof (int);
+      if (errno != 0)
+	{
+	  /* Warning, not error, in case we are attached; sometimes the
+	     kernel doesn't let us at the registers.  */
+	  char *err = strerror (errno);
+	  char *msg = alloca (strlen (err) + 128);
+	  sprintf (msg, "reading register %d: %s", regno, err);
+	  error (msg);
+	  goto error_exit;
+	}
+    }
+ error_exit:;
+}
+
+/* Fetch all registers, or just one, from the child process.  */
+
+void
+fetch_inferior_registers (regno)
+     int regno;
+{
+  if (regno == -1 || regno == 0)
+    for (regno = 0; regno < NUM_REGS; regno++)
+      fetch_register (regno);
+  else
+    fetch_register (regno);
+}
+
+/* Store our register values back into the inferior.
+   If REGNO is -1, do this for all registers.
+   Otherwise, REGNO specifies which register (so we can save time).  */
+
+void
+store_inferior_registers (regno)
+     int regno;
+{
+  register unsigned int regaddr;
+  char buf[80];
+  extern char registers[];
+  register int i;
+  unsigned int offset = U_REGS_OFFSET;
+  int scratch;
+
+  if (regno >= 0)
+    {
+      regaddr = register_addr (regno, offset);
+      errno = 0;
+      for (i = 0; i < REGISTER_RAW_SIZE (regno); i += sizeof(int))
+	{
+	  errno = 0;
+	  ptrace (PT_WRITE_U, inferior_pid, (PTRACE_ARG3_TYPE) regaddr,
+		  *(int *) &registers[REGISTER_BYTE (regno) + i]);
+	  if (errno != 0)
+	    {
+	      /* Warning, not error, in case we are attached; sometimes the
+		 kernel doesn't let us at the registers.  */
+	      char *err = strerror (errno);
+	      char *msg = alloca (strlen (err) + 128);
+	      sprintf (msg, "writing register %d: %s",
+		       regno, err);
+	      error (msg);
+	      return;
+	    }
+	  regaddr += sizeof(int);
+	}
+    }
+  else
+    for (regno = 0; regno < NUM_REGS; regno++)
+      store_inferior_registers (regno);
+}
+
+/* NOTE! I tried using PTRACE_READDATA, etc., to read and write memory
+   in the NEW_SUN_PTRACE case.
+   It ought to be straightforward.  But it appears that writing did
+   not write the data that I specified.  I cannot understand where
+   it got the data that it actually did write.  */
+
+/* Copy LEN bytes from inferior's memory starting at MEMADDR
+   to debugger memory starting at MYADDR.  */
+
+read_inferior_memory (memaddr, myaddr, len)
+     CORE_ADDR memaddr;
+     char *myaddr;
+     int len;
+{
+  register int i;
+  /* Round starting address down to longword boundary.  */
+  register CORE_ADDR addr = memaddr & -sizeof (int);
+  /* Round ending address up; get number of longwords that makes.  */
+  register int count
+  = (((memaddr + len) - addr) + sizeof (int) - 1) / sizeof (int);
+  /* Allocate buffer of that many longwords.  */
+  register int *buffer = (int *) alloca (count * sizeof (int));
+
+  /* Read all the longwords */
+  for (i = 0; i < count; i++, addr += sizeof (int))
+    {
+      buffer[i] = ptrace (PT_READ_I, inferior_pid, (PTRACE_ARG3_TYPE) addr, 0);
+    }
+
+  /* Copy appropriate bytes out of the buffer.  */
+  memcpy (myaddr, (char *) buffer + (memaddr & (sizeof (int) - 1)), len);
+}
+
+/* Copy LEN bytes of data from debugger memory at MYADDR
+   to inferior's memory at MEMADDR.
+   On failure (cannot write the inferior)
+   returns the value of errno.  */
+
+int
+write_inferior_memory (memaddr, myaddr, len)
+     CORE_ADDR memaddr;
+     char *myaddr;
+     int len;
+{
+  register int i;
+  /* Round starting address down to longword boundary.  */
+  register CORE_ADDR addr = memaddr & -sizeof (int);
+  /* Round ending address up; get number of longwords that makes.  */
+  register int count
+  = (((memaddr + len) - addr) + sizeof (int) - 1) / sizeof (int);
+  /* Allocate buffer of that many longwords.  */
+  register int *buffer = (int *) alloca (count * sizeof (int));
+  extern int errno;
+
+  /* Fill start and end extra bytes of buffer with existing memory data.  */
+
+  buffer[0] = ptrace (PT_READ_I, inferior_pid,
+		      (PTRACE_ARG3_TYPE) addr, 0);
+
+  if (count > 1)
+    {
+      buffer[count - 1]
+	= ptrace (PT_READ_I, inferior_pid,
+	      	  (PTRACE_ARG3_TYPE) addr + (count - 1) * sizeof (int), 0);
+    }
+
+  /* Copy data to be written over corresponding part of buffer */
+
+  memcpy ((char *) buffer + (memaddr & (sizeof (int) - 1)), myaddr, len);
+
+  /* Write the entire buffer.  */
+
+  for (i = 0; i < count; i++, addr += sizeof (int))
+    {
+      errno = 0;
+      ptrace (PT_WRITE_I, inferior_pid, (PTRACE_ARG3_TYPE) addr, buffer[i]);
+      if (errno)
+	return errno;
+    }
+
+  return 0;
+}
+
+void
+initialize ()
+{
+  inferior_pid = 0;
+}
+
+int
+have_inferior_p ()
+{
+  return inferior_pid != 0;
+}
+
+/* Some systems don't provide all the registers on a trap.  Use SS as a
+   default if so.  */
+
+#ifndef tDS
+#define tDS tSS
+#endif
+#ifndef tES
+#define tES tSS
+#endif
+#ifndef tFS
+#define tFS tSS
+#endif
+#ifndef tGS
+#define tGS tSS
+#endif
+
+/* These tables map between the registers on a trap frame, and the register
+   order used by the rest of GDB.  */
+/* this table must line up with REGISTER_NAMES in tm-i386.h */
+/* symbols like 'tEAX' come from <machine/reg.h> */
+static int tregmap[] = 
+{
+  tEAX, tECX, tEDX, tEBX,
+  tESP, tEBP, tESI, tEDI,
+  tEIP, tEFLAGS, tCS, tSS,
+  tDS, tES, tFS, tGS
+};
+
+#ifdef sEAX
+static int sregmap[] = 
+{
+  sEAX, sECX, sEDX, sEBX,
+  sESP, sEBP, sESI, sEDI,
+  sEIP, sEFLAGS, sCS, sSS
+};
+#else /* No sEAX */
+
+/* FreeBSD has decided to collapse the s* and t* symbols.  So if the s*
+   ones aren't around, use the t* ones for sregmap too.  */
+
+static int sregmap[] = 
+{
+  tEAX, tECX, tEDX, tEBX,
+  tESP, tEBP, tESI, tEDI,
+  tEIP, tEFLAGS, tCS, tSS,
+  tDS, tES, tFS, tGS
+};
+#endif /* No sEAX */
+
+/* blockend is the value of u.u_ar0, and points to the
+   place where ES is stored.  */
+
+int
+i386_register_u_addr (blockend, regnum)
+     int blockend;
+     int regnum;
+{
+  /* The following condition is a kludge to get at the proper register map
+     depending upon the state of pcb_flag.
+     The proper condition would be
+     if (u.u_pcb.pcb_flag & FM_TRAP)
+     but that would require a ptrace call here and wouldn't work
+     for corefiles.  */
+
+  if (blockend < 0x1fcc)
+    return (blockend + 4 * tregmap[regnum]);
+  else
+    return (blockend + 4 * sregmap[regnum]);
+}

gnu/usr.bin/gdb/gdbserver/Makefile

@@ -0,0 +1,17 @@
+#	$Id: Makefile,v 1.13.2.1 1997/02/02 20:46:32 joerg Exp $
+
+GDBDIR=	${.CURDIR}/../../../../contrib/gdb
+.PATH:	${GDBDIR}/gdb/gdbserver
+.PATH:	${GDBDIR}/gdb
+.PATH:	${GDBDIR}/opcodes
+
+PROG=	gdbserver
+BINDIR=	/usr/bin
+
+SRCS=	remote-utils.c utils.c server.c
+SRCS+=	low-fbsd.c
+
+CFLAGS+=-I${.CURDIR}/../gdb -I${.CURDIR}/../bfd -I${GDBDIR}/gdb -I${GDBDIR}/bfd
+CFLAGS+=-DNO_MMALLOC
+
+.include <bsd.prog.mk>

gnu/usr.bin/gdb/gdbserver/low-fbsd.c

@@ -0,0 +1,433 @@
+/* Low level interface to ptrace, for the remote server for GDB.
+   Copyright (C) 1995 Free Software Foundation, Inc.
+
+This file is part of GDB.
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
+
+#include "defs.h"
+#include <sys/wait.h>
+#include "frame.h"
+#include "inferior.h"
+
+#include <stdio.h>
+#include <sys/param.h>
+#include <sys/dir.h>
+#include <sys/user.h>
+#include <signal.h>
+#include <sys/ioctl.h>
+#include <sgtty.h>
+#include <fcntl.h>
+
+/***************Begin MY defs*********************/
+int quit_flag = 0;
+char registers[REGISTER_BYTES];
+
+/* Index within `registers' of the first byte of the space for
+   register N.  */
+
+
+char buf2[MAX_REGISTER_RAW_SIZE];
+/***************End MY defs*********************/
+
+#include <sys/ptrace.h>
+#include <machine/reg.h>
+
+extern char **environ;
+extern int inferior_pid;
+void quit (), perror_with_name ();
+int query ();
+
+/* Start an inferior process and returns its pid.
+   ALLARGS is a vector of program-name and args.
+   ENV is the environment vector to pass.  */
+
+int
+create_inferior (program, allargs)
+     char *program;
+     char **allargs;
+{
+  int pid;
+
+  pid = fork ();
+  if (pid < 0)
+    perror_with_name ("fork");
+
+  if (pid == 0)
+    {
+      ptrace (PT_TRACE_ME, 0, 0, 0);
+
+      execv (program, allargs);
+
+      fprintf (stderr, "Cannot exec %s: %s.\n", program, strerror(errno));
+      fflush (stderr);
+      _exit (0177);
+    }
+
+  return pid;
+}
+
+/* Kill the inferior process.  Make us have no inferior.  */
+
+void
+kill_inferior ()
+{
+  if (inferior_pid == 0)
+    return;
+  ptrace (PT_KILL, inferior_pid, 0, 0);
+  wait (0);
+  /*************inferior_died ();****VK**************/
+}
+
+/* Return nonzero if the given thread is still alive.  */
+int
+mythread_alive (pid)
+     int pid;
+{
+  return 1;
+}
+
+/* Wait for process, returns status */
+
+unsigned char
+mywait (status)
+     char *status;
+{
+  int pid;
+  int w;
+
+  pid = wait (&w);
+  if (pid != inferior_pid)
+    perror_with_name ("wait");
+
+  if (WIFEXITED (w))
+    {
+      fprintf (stderr, "\nChild exited with retcode = %x \n", WEXITSTATUS (w));
+      *status = 'W';
+      return ((unsigned char) WEXITSTATUS (w));
+    }
+  else if (!WIFSTOPPED (w))
+    {
+      fprintf (stderr, "\nChild terminated with signal = %x \n", WTERMSIG (w));
+      *status = 'X';
+      return ((unsigned char) WTERMSIG (w));
+    }
+
+  fetch_inferior_registers (0);
+
+  *status = 'T';
+  return ((unsigned char) WSTOPSIG (w));
+}
+
+/* Resume execution of the inferior process.
+   If STEP is nonzero, single-step it.
+   If SIGNAL is nonzero, give it that signal.  */
+
+void
+myresume (step, signal)
+     int step;
+     int signal;
+{
+  errno = 0;
+  ptrace (step ? PT_STEP : PT_CONTINUE, inferior_pid,
+	  (PTRACE_ARG3_TYPE) 1, signal);
+  if (errno)
+    perror_with_name ("ptrace");
+}
+
+
+#if !defined (offsetof)
+#define offsetof(TYPE, MEMBER) ((unsigned long) &((TYPE *)0)->MEMBER)
+#endif
+
+/* U_REGS_OFFSET is the offset of the registers within the u area.  */
+#if !defined (U_REGS_OFFSET)
+#define U_REGS_OFFSET \
+  ptrace (PT_READ_U, inferior_pid, \
+          (PTRACE_ARG3_TYPE) (offsetof (struct user, u_ar0)), 0) \
+    - KERNEL_U_ADDR
+#endif
+
+unsigned int
+register_addr (regno, blockend)
+     int regno;
+     int blockend;
+{
+  int addr;
+
+  if (regno < 0 || regno >= ARCH_NUM_REGS)
+    error ("Invalid register number %d.", regno);
+
+  REGISTER_U_ADDR (addr, blockend, regno);
+
+  return addr;
+}
+
+/* Fetch one register.  */
+
+static void
+fetch_register (regno)
+     int regno;
+{
+  register unsigned int regaddr;
+  char buf[MAX_REGISTER_RAW_SIZE];
+  register int i;
+
+  /* Offset of registers within the u area.  */
+  unsigned int offset;
+
+  offset = U_REGS_OFFSET;
+
+  regaddr = register_addr (regno, offset);
+  for (i = 0; i < REGISTER_RAW_SIZE (regno); i += sizeof (int))
+    {
+      errno = 0;
+      *(int *) &registers[ regno * sizeof(int) + i] = 
+	  ptrace (PT_READ_U, inferior_pid, (PTRACE_ARG3_TYPE) regaddr, 0);
+      regaddr += sizeof (int);
+      if (errno != 0)
+	{
+	  /* Warning, not error, in case we are attached; sometimes the
+	     kernel doesn't let us at the registers.  */
+	  char *err = strerror (errno);
+	  char *msg = alloca (strlen (err) + 128);
+	  sprintf (msg, "reading register %d: %s", regno, err);
+	  error (msg);
+	  goto error_exit;
+	}
+    }
+ error_exit:;
+}
+
+/* Fetch all registers, or just one, from the child process.  */
+
+void
+fetch_inferior_registers (regno)
+     int regno;
+{
+  if (regno == -1 || regno == 0)
+    for (regno = 0; regno < NUM_REGS; regno++)
+      fetch_register (regno);
+  else
+    fetch_register (regno);
+}
+
+/* Store our register values back into the inferior.
+   If REGNO is -1, do this for all registers.
+   Otherwise, REGNO specifies which register (so we can save time).  */
+
+void
+store_inferior_registers (regno)
+     int regno;
+{
+  register unsigned int regaddr;
+  char buf[80];
+  extern char registers[];
+  register int i;
+  unsigned int offset = U_REGS_OFFSET;
+  int scratch;
+
+  if (regno >= 0)
+    {
+      regaddr = register_addr (regno, offset);
+      errno = 0;
+      for (i = 0; i < REGISTER_RAW_SIZE (regno); i += sizeof(int))
+	{
+	  errno = 0;
+	  ptrace (PT_WRITE_U, inferior_pid, (PTRACE_ARG3_TYPE) regaddr,
+		  *(int *) &registers[REGISTER_BYTE (regno) + i]);
+	  if (errno != 0)
+	    {
+	      /* Warning, not error, in case we are attached; sometimes the
+		 kernel doesn't let us at the registers.  */
+	      char *err = strerror (errno);
+	      char *msg = alloca (strlen (err) + 128);
+	      sprintf (msg, "writing register %d: %s",
+		       regno, err);
+	      error (msg);
+	      return;
+	    }
+	  regaddr += sizeof(int);
+	}
+    }
+  else
+    for (regno = 0; regno < NUM_REGS; regno++)
+      store_inferior_registers (regno);
+}
+
+/* NOTE! I tried using PTRACE_READDATA, etc., to read and write memory
+   in the NEW_SUN_PTRACE case.
+   It ought to be straightforward.  But it appears that writing did
+   not write the data that I specified.  I cannot understand where
+   it got the data that it actually did write.  */
+
+/* Copy LEN bytes from inferior's memory starting at MEMADDR
+   to debugger memory starting at MYADDR.  */
+
+read_inferior_memory (memaddr, myaddr, len)
+     CORE_ADDR memaddr;
+     char *myaddr;
+     int len;
+{
+  register int i;
+  /* Round starting address down to longword boundary.  */
+  register CORE_ADDR addr = memaddr & -sizeof (int);
+  /* Round ending address up; get number of longwords that makes.  */
+  register int count
+  = (((memaddr + len) - addr) + sizeof (int) - 1) / sizeof (int);
+  /* Allocate buffer of that many longwords.  */
+  register int *buffer = (int *) alloca (count * sizeof (int));
+
+  /* Read all the longwords */
+  for (i = 0; i < count; i++, addr += sizeof (int))
+    {
+      buffer[i] = ptrace (PT_READ_I, inferior_pid, (PTRACE_ARG3_TYPE) addr, 0);
+    }
+
+  /* Copy appropriate bytes out of the buffer.  */
+  memcpy (myaddr, (char *) buffer + (memaddr & (sizeof (int) - 1)), len);
+}
+
+/* Copy LEN bytes of data from debugger memory at MYADDR
+   to inferior's memory at MEMADDR.
+   On failure (cannot write the inferior)
+   returns the value of errno.  */
+
+int
+write_inferior_memory (memaddr, myaddr, len)
+     CORE_ADDR memaddr;
+     char *myaddr;
+     int len;
+{
+  register int i;
+  /* Round starting address down to longword boundary.  */
+  register CORE_ADDR addr = memaddr & -sizeof (int);
+  /* Round ending address up; get number of longwords that makes.  */
+  register int count
+  = (((memaddr + len) - addr) + sizeof (int) - 1) / sizeof (int);
+  /* Allocate buffer of that many longwords.  */
+  register int *buffer = (int *) alloca (count * sizeof (int));
+  extern int errno;
+
+  /* Fill start and end extra bytes of buffer with existing memory data.  */
+
+  buffer[0] = ptrace (PT_READ_I, inferior_pid,
+		      (PTRACE_ARG3_TYPE) addr, 0);
+
+  if (count > 1)
+    {
+      buffer[count - 1]
+	= ptrace (PT_READ_I, inferior_pid,
+	      	  (PTRACE_ARG3_TYPE) addr + (count - 1) * sizeof (int), 0);
+    }
+
+  /* Copy data to be written over corresponding part of buffer */
+
+  memcpy ((char *) buffer + (memaddr & (sizeof (int) - 1)), myaddr, len);
+
+  /* Write the entire buffer.  */
+
+  for (i = 0; i < count; i++, addr += sizeof (int))
+    {
+      errno = 0;
+      ptrace (PT_WRITE_I, inferior_pid, (PTRACE_ARG3_TYPE) addr, buffer[i]);
+      if (errno)
+	return errno;
+    }
+
+  return 0;
+}
+
+void
+initialize ()
+{
+  inferior_pid = 0;
+}
+
+int
+have_inferior_p ()
+{
+  return inferior_pid != 0;
+}
+
+/* Some systems don't provide all the registers on a trap.  Use SS as a
+   default if so.  */
+
+#ifndef tDS
+#define tDS tSS
+#endif
+#ifndef tES
+#define tES tSS
+#endif
+#ifndef tFS
+#define tFS tSS
+#endif
+#ifndef tGS
+#define tGS tSS
+#endif
+
+/* These tables map between the registers on a trap frame, and the register
+   order used by the rest of GDB.  */
+/* this table must line up with REGISTER_NAMES in tm-i386.h */
+/* symbols like 'tEAX' come from <machine/reg.h> */
+static int tregmap[] = 
+{
+  tEAX, tECX, tEDX, tEBX,
+  tESP, tEBP, tESI, tEDI,
+  tEIP, tEFLAGS, tCS, tSS,
+  tDS, tES, tFS, tGS
+};
+
+#ifdef sEAX
+static int sregmap[] = 
+{
+  sEAX, sECX, sEDX, sEBX,
+  sESP, sEBP, sESI, sEDI,
+  sEIP, sEFLAGS, sCS, sSS
+};
+#else /* No sEAX */
+
+/* FreeBSD has decided to collapse the s* and t* symbols.  So if the s*
+   ones aren't around, use the t* ones for sregmap too.  */
+
+static int sregmap[] = 
+{
+  tEAX, tECX, tEDX, tEBX,
+  tESP, tEBP, tESI, tEDI,
+  tEIP, tEFLAGS, tCS, tSS,
+  tDS, tES, tFS, tGS
+};
+#endif /* No sEAX */
+
+/* blockend is the value of u.u_ar0, and points to the
+   place where ES is stored.  */
+
+int
+i386_register_u_addr (blockend, regnum)
+     int blockend;
+     int regnum;
+{
+  /* The following condition is a kludge to get at the proper register map
+     depending upon the state of pcb_flag.
+     The proper condition would be
+     if (u.u_pcb.pcb_flag & FM_TRAP)
+     but that would require a ptrace call here and wouldn't work
+     for corefiles.  */
+
+  if (blockend < 0x1fcc)
+    return (blockend + 4 * tregmap[regnum]);
+  else
+    return (blockend + 4 * sregmap[regnum]);
+}