Johns release

1 files changed, 983 insertions, 0 deletions

diff --git a/gdb/convex-xdep.c b/gdb/convex-xdep.c
new file mode 100644
index 0000000..f9f44a0
--- /dev/null
+++ b/gdb/convex-xdep.c
@@ -0,0 +1,983 @@
+/* Convex stuff for GDB.
+   Copyright (C) 1990-1991 Free Software Foundation, Inc.
+
+This file is part of GDB.
+
+GDB 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 1, or (at your option)
+any later version.
+
+GDB 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 GDB; see the file COPYING.  If not, write to
+the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
+
+#include <stdio.h>
+#include "defs.h"
+#include "param.h"
+#include "command.h"
+#include "symtab.h"
+#include "value.h"
+#include "frame.h"
+#include "inferior.h"
+#include "wait.h"
+
+#include <signal.h>
+#include <fcntl.h>
+#include "gdbcore.h"
+
+#include <sys/param.h>
+#include <sys/dir.h>
+#include <sys/user.h>
+#include <sys/ioctl.h>
+#include <sys/pcntl.h>
+#include <sys/thread.h>
+#include <sys/proc.h>
+#include <sys/file.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+
+#include <convex/vmparam.h>
+#include <convex/filehdr.h>
+#include <convex/opthdr.h>
+#include <convex/scnhdr.h>
+#include <convex/core.h>
+
+/* Per-thread data, read from the inferior at each stop and written
+   back at each resume.  */
+
+/* Number of active threads.
+   Tables are valid for thread numbers less than this.  */
+
+static int n_threads;
+
+#define MAXTHREADS 8
+		
+/* Thread state.  The remaining data is valid only if this is PI_TALIVE.  */
+
+static int thread_state[MAXTHREADS];
+
+/* Stop pc, signal, signal subcode */
+
+static int thread_pc[MAXTHREADS];
+static int thread_signal[MAXTHREADS];
+static int thread_sigcode[MAXTHREADS];	
+
+/* Thread registers.
+   If thread is selected, the regs are in registers[] instead.  */
+
+static char thread_regs[MAXTHREADS][REGISTER_BYTES];
+
+/* 1 if the top frame on the thread's stack was a context frame,
+   meaning that the kernel is up to something and we should not
+   touch the thread at all except to resume it.  */
+
+static char thread_is_in_kernel[MAXTHREADS];
+
+/* The currently selected thread's number.  */
+
+static int inferior_thread;
+
+/* Inferior process's file handle and a process control block
+   to feed args to ioctl with.  */
+
+static int inferior_fd;
+static struct pcntl ps;
+
+/* SOFF file headers for exec or core file.  */
+
+static FILEHDR filehdr;
+static OPTHDR opthdr;
+static SCNHDR scnhdr;
+
+/* Address maps constructed from section headers of exec and core files.
+   Defines process address -> file address translation.  */
+
+struct pmap 
+{
+    long mem_addr;		/* process start address */
+    long mem_end;		/* process end+1 address */
+    long file_addr;		/* file start address */
+    long thread;		/* -1 shared; 0,1,... thread-local */
+    long type;			/* S_TEXT S_DATA S_BSS S_TBSS etc */
+    long which;			/* used to sort map for info files */
+};
+
+static int n_exec, n_core;
+static struct pmap exec_map[100];
+static struct pmap core_map[100];
+
+/* Offsets in the core file of core_context and core_tcontext blocks.  */
+
+static int context_offset;
+static int tcontext_offset[MAXTHREADS];
+
+/* Core file control blocks.  */
+
+static struct core_context_v70 c;
+static struct core_tcontext_v70 tc;
+static struct user u;
+static thread_t th;
+static proc_t pr;
+
+/* The registers of the currently selected thread.  */
+
+extern char registers[REGISTER_BYTES];
+
+/* Vector and communication registers from core dump or from inferior.
+   These are read on demand, ie, not normally valid.  */
+
+static struct vecst vector_registers;
+static struct creg_ctx comm_registers;
+
+/* Flag, set on a vanilla CONT command and cleared when the inferior
+   is continued.  */
+
+static int all_continue;
+
+/* Flag, set when the inferior is continued by a vanilla CONT command,
+   cleared if it is continued for any other purpose.  */
+
+static int thread_switch_ok;
+
+/* Stack of signals recieved from threads but not yet delivered to gdb.  */
+
+struct threadpid 
+{
+    int pid;
+    int thread;
+    int signo;
+    int subsig;
+    int pc;
+};
+
+static struct threadpid signal_stack_bot[100];
+static struct threadpid *signal_stack = signal_stack_bot;
+
+/* How to detect empty stack -- bottom frame is all zero.  */
+
+#define signal_stack_is_empty() (signal_stack->pid == 0)
+
+/* Mode controlled by SET PIPE command, controls the psw SEQ bit
+   which forces each instruction to complete before the next one starts.  */
+
+static int sequential = 0;
+
+/* Mode controlled by the SET PARALLEL command.  Values are:
+   0  concurrency limit 1 thread, dynamic scheduling
+   1  no concurrency limit, dynamic scheduling
+   2  no concurrency limit, fixed scheduling  */
+
+static int parallel = 1;
+
+/* Mode controlled by SET BASE command, output radix for unformatted
+   integer typeout, as in argument lists, aggregates, and so on.
+   Zero means guess whether it's an address (hex) or not (decimal).  */
+
+static int output_radix = 0;
+
+/* Signal subcode at last thread stop.  */
+
+static int stop_sigcode;
+
+/* Hack, see wait() below.  */
+
+static int exec_trap_timer;
+
+#include "gdbcmd.h"
+
+/* Nonzero if we are debugging an attached outside process
+   rather than an inferior.  */
+
+extern int attach_flag;
+
+
+
+static struct type *vector_type ();
+static long *read_vector_register ();
+static long *read_vector_register_1 ();
+static void write_vector_register ();
+static REGISTER_TYPE read_comm_register ();
+static void write_comm_register ();
+static void convex_cont_command ();
+static void thread_continue ();
+static void select_thread ();
+static void scan_stack ();
+static void set_fixed_scheduling ();
+static char *subsig_name ();
+static void psw_info ();
+static sig_noop ();
+static ptr_cmp ();
+
+extern char *sys_siglist[];
+
+/* Execute ptrace.  Convex V7 replaced ptrace with pattach.
+   Allow ptrace (0) as a no-op.  */
+
+int
+call_ptrace (request, pid, procaddr, buf)
+     int request, pid, procaddr, buf;
+{
+  if (request == 0)
+    return;
+  error ("no ptrace");
+}
+
+/* Replacement for system execle routine.
+   Convert it to an equivalent exect, which pattach insists on.  */
+
+execle (name, argv)
+     char *name, *argv;
+{
+  char ***envp = (char ***) &argv;
+  while (*envp++) ;
+
+  signal (SIGTRAP, sig_noop);
+  exect (name, &argv, *envp);
+}
+
+/* Stupid handler for stupid trace trap that otherwise causes
+   startup to stupidly hang.  */
+
+static sig_noop () 
+{}
+
+/* Read registers from inferior into registers[] array.
+   For convex, they are already there, read in when the inferior stops.  */
+
+void
+fetch_inferior_registers (regno)
+     int regno;
+{
+}
+
+/* Store our register values back into the inferior.
+   For Convex, do this only once, right before resuming inferior.  */
+
+store_inferior_registers (regno)
+     int regno;
+{
+}
+
+/* Copy LEN bytes from inferior's memory starting at MEMADDR
+   to debugger memory starting at MYADDR. 
+   On failure (cannot read from inferior, usually because address is out
+   of bounds) returns the value of errno. */
+
+int
+read_inferior_memory (memaddr, myaddr, len)
+     CORE_ADDR memaddr;
+     char *myaddr;
+     int len;
+{
+  errno = 0;
+  while (len > 0)
+    {
+      /* little-known undocumented max request size */
+      int i = (len < 12288) ? len : 12288;
+
+      lseek (inferior_fd, memaddr, 0);
+      read (inferior_fd, myaddr, i);
+
+      memaddr += i;
+      myaddr += i;
+      len -= i;
+    }
+  if (errno) 
+    bzero (myaddr, len);
+  return errno;
+}
+
+/* Copy LEN bytes of data from debugger memory at MYADDR
+   to inferior's memory at MEMADDR.
+   Returns errno on failure (cannot write the inferior) */
+
+int
+write_inferior_memory (memaddr, myaddr, len)
+     CORE_ADDR memaddr;
+     char *myaddr;
+     int len;
+{
+  errno = 0;
+  lseek (inferior_fd, memaddr, 0);
+  write (inferior_fd, myaddr, len);
+  return errno;
+}
+
+/* Here from create_inferior when the inferior process has been created
+   and started up.  We must do a pattach to grab it for debugging.
+
+   Also, intercept the CONT command by altering its dispatch address.  */
+
+create_inferior_hook (pid)
+    int pid;
+{
+  static char cont[] = "cont";
+  static char cont1[] = "c";
+  char *linep = cont;
+  char *linep1 = cont1;
+  char **line = &linep;
+  char **line1 = &linep1;
+  struct cmd_list_element *c;
+
+  c = lookup_cmd (line, cmdlist, "", 0);
+  c->function = convex_cont_command;
+  c = lookup_cmd (line1, cmdlist, "", 0);
+  c->function = convex_cont_command;
+
+  inferior_fd = pattach (pid, O_EXCL);
+  if (inferior_fd < 0)
+    perror_with_name ("pattach");
+  inferior_thread = 0;
+  set_fixed_scheduling (pid, parallel == 2);
+}
+
+/* Attach process PID for debugging.  */
+
+attach (pid)
+    int pid;
+{
+  int fd = pattach (pid, O_EXCL);
+  if (fd < 0)
+    perror_with_name ("pattach");
+  attach_flag = 1;
+  /* wait for strange kernel reverberations to go away */
+  sleep (1);
+
+  setpgrp (pid, pid);
+
+  inferior_fd = fd;
+  inferior_thread = 0;
+  return pid;
+}
+
+/* Stop debugging the process whose number is PID
+   and continue it with signal number SIGNAL.
+   SIGNAL = 0 means just continue it.  */
+
+void
+detach (signal)
+     int signal;
+{
+  signal_stack = signal_stack_bot;
+  thread_continue (-1, 0, signal);
+  ioctl (inferior_fd, PIXDETACH, &ps);
+  close (inferior_fd);
+  inferior_fd = 0;
+  attach_flag = 0;
+}
+
+/* Kill off the inferior process.  */
+
+kill_inferior ()
+{
+  if (inferior_pid == 0)
+    return;
+  ioctl (inferior_fd, PIXTERMINATE, 0);
+  wait (0);
+  target_mourn_inferior ();
+}
+
+/* This is used when GDB is exiting.  It gives less chance of error.*/
+
+kill_inferior_fast ()
+{
+  if (inferior_pid == 0)
+    return;
+  ioctl (inferior_fd, PIXTERMINATE, 0);
+  wait (0);
+}
+
+/* Read vector register REG, and return a pointer to the value.  */
+
+static long *
+read_vector_register (reg)
+    int reg;
+{
+  if (have_inferior_p ())
+    {
+      errno = 0;
+      ps.pi_buffer = (char *) &vector_registers;
+      ps.pi_nbytes = sizeof vector_registers;
+      ps.pi_offset = 0;
+      ps.pi_thread = inferior_thread;
+      ioctl (inferior_fd, PIXRDVREGS, &ps);
+      if (errno)
+	bzero (&vector_registers, sizeof vector_registers);
+    }
+  else if (corechan >= 0)
+    {
+      lseek (corechan, tcontext_offset[inferior_thread], 0);
+      if (myread (corechan, &tc, sizeof tc) < 0)
+	perror_with_name (corefile);
+      lseek (corechan, tc.core_thread_p, 0);
+      if (myread (corechan, &th, sizeof th) < 0)
+	perror_with_name (corefile);
+      lseek (corechan, tc.core_vregs_p, 0);
+      if (myread (corechan, &vector_registers, 16*128) < 0)
+	perror_with_name (corefile);
+      vector_registers.vm[0] = th.t_vect_ctx.vc_vm[0];
+      vector_registers.vm[1] = th.t_vect_ctx.vc_vm[1];
+      vector_registers.vls = th.t_vect_ctx.vc_vls;
+    }
+
+  return read_vector_register_1 (reg);
+}
+
+/* Return a pointer to vector register REG, which must already have been
+   fetched from the inferior or core file.  */
+
+static long *
+read_vector_register_1 (reg) 
+    int reg;
+{
+  switch (reg)
+    {
+    case VM_REGNUM:
+      return (long *) vector_registers.vm;
+    case VS_REGNUM:
+      return (long *) &vector_registers.vls;
+    case VL_REGNUM:
+      return 1 + (long *) &vector_registers.vls;
+    default:
+      return (long *) &vector_registers.vr[reg];
+    }
+}
+
+/* Write vector register REG, element ELEMENT, new value VAL.
+   NB: must use read-modify-write on the entire vector state,
+   since pattach does not do offsetted writes correctly.  */
+
+static void
+write_vector_register (reg, element, val)
+    int reg, element;
+    REGISTER_TYPE val;
+{
+  if (have_inferior_p ())
+    {
+      errno = 0;
+      ps.pi_thread = inferior_thread;
+      ps.pi_offset = 0;
+      ps.pi_buffer = (char *) &vector_registers;
+      ps.pi_nbytes = sizeof vector_registers;
+
+      ioctl (inferior_fd, PIXRDVREGS, &ps);
+
+      switch (reg)
+	{
+	case VL_REGNUM:
+	  vector_registers.vls =
+	    (vector_registers.vls & 0xffffffff00000000LL)
+	      + (unsigned long) val;
+	  break;
+
+	case VS_REGNUM:
+	  vector_registers.vls =
+	    (val << 32) + (unsigned long) vector_registers.vls;
+	  break;
+	    
+	default:
+	  vector_registers.vr[reg].el[element] = val;
+	  break;
+	}
+
+      ioctl (inferior_fd, PIXWRVREGS, &ps);
+
+      if (errno)
+	perror_with_name ("writing vector register");
+    }
+}
+
+/* Return the contents of communication register NUM.  */ 
+
+static REGISTER_TYPE 
+read_comm_register (num)
+     int num;
+{
+  if (have_inferior_p ())
+    {
+      ps.pi_buffer = (char *) &comm_registers;
+      ps.pi_nbytes = sizeof comm_registers;
+      ps.pi_offset = 0;
+      ps.pi_thread = inferior_thread;
+      ioctl (inferior_fd, PIXRDCREGS, &ps);
+    }
+  return comm_registers.crreg.r4[num];
+}
+
+/* Store a new value VAL into communication register NUM.  
+   NB: Must use read-modify-write on the whole comm register set
+   since pattach does not do offsetted writes correctly.  */
+
+static void
+write_comm_register (num, val)
+     int num;
+     REGISTER_TYPE val;
+{
+  if (have_inferior_p ())
+    {
+      ps.pi_buffer = (char *) &comm_registers;
+      ps.pi_nbytes = sizeof comm_registers;
+      ps.pi_offset = 0;
+      ps.pi_thread = inferior_thread;
+      ioctl (inferior_fd, PIXRDCREGS, &ps);
+      comm_registers.crreg.r4[num] = val;
+      ioctl (inferior_fd, PIXWRCREGS, &ps);
+    }
+}
+
+/* Resume execution of the inferior process.
+   If STEP is nonzero, single-step it.
+   If SIGNAL is nonzero, give it that signal.  */
+
+void
+resume (step, signal)
+     int step;
+     int signal;
+{
+  errno = 0;
+  if (step || signal)
+    thread_continue (inferior_thread, step, signal);
+  else
+    thread_continue (-1, 0, 0);
+}
+
+/* Maybe resume some threads.
+   THREAD is which thread to resume, or -1 to resume them all.
+   STEP and SIGNAL are as in resume.
+
+   Global variable ALL_CONTINUE is set when we are here to do a
+   `cont' command; otherwise we may be doing `finish' or a call or
+   something else that will not tolerate an automatic thread switch.
+
+   If there are stopped threads waiting to deliver signals, and
+   ALL_CONTINUE, do not actually resume anything.  gdb will do a wait
+   and see one of the stopped threads in the queue.  */
+
+static void
+thread_continue (thread, step, signal)
+     int thread, step, signal;
+{
+  int n;
+
+  /* If we are to continue all threads, but not for the CONTINUE command,
+     pay no attention and continue only the selected thread.  */
+
+  if (thread < 0 && ! all_continue)
+    thread = inferior_thread;
+
+  /* If we are not stepping, we have now executed the continue part
+     of a CONTINUE command.  */
+
+  if (! step)
+    all_continue = 0;
+
+  /* Allow wait() to switch threads if this is an all-out continue.  */
+
+  thread_switch_ok = thread < 0;
+
+  /* If there are threads queued up, don't resume.  */
+
+  if (thread_switch_ok && ! signal_stack_is_empty ())
+    return;
+
+  /* OK, do it.  */
+
+  for (n = 0; n < n_threads; n++)
+    if (thread_state[n] == PI_TALIVE)
+      {
+	select_thread (n);
+
+	if ((thread < 0 || n == thread) && ! thread_is_in_kernel[n])
+	  {
+	    /* Blam the trace bits in the stack's saved psws to match 
+	       the desired step mode.  This is required so that
+	       single-stepping a return doesn't restore a psw with a
+	       clear trace bit and fly away, and conversely,
+	       proceeding through a return in a routine that was
+	       stepped into doesn't cause a phantom break by restoring
+	       a psw with the trace bit set. */
+	    scan_stack (PSW_T_BIT, step);
+	    scan_stack (PSW_S_BIT, sequential);
+	  }
+
+	ps.pi_buffer = registers;
+	ps.pi_nbytes = REGISTER_BYTES;
+	ps.pi_offset = 0;
+	ps.pi_thread = n;
+	if (! thread_is_in_kernel[n])
+	  if (ioctl (inferior_fd, PIXWRREGS, &ps))
+	    perror_with_name ("PIXWRREGS");
+
+	if (thread < 0 || n == thread)
+	  {
+	    ps.pi_pc = 1;
+	    ps.pi_signo = signal;
+	    if (ioctl (inferior_fd, step ? PIXSTEP : PIXCONTINUE, &ps) < 0)
+	      perror_with_name ("PIXCONTINUE");
+	  }
+      }
+
+  if (ioctl (inferior_fd, PIXRUN, &ps) < 0)
+    perror_with_name ("PIXRUN");
+}
+
+/* Replacement for system wait routine.  
+
+   The system wait returns with one or more threads stopped by
+   signals.  Put stopped threads on a stack and return them one by
+   one, so that it appears that wait returns one thread at a time.
+
+   Global variable THREAD_SWITCH_OK is set when gdb can tolerate wait
+   returning a new thread.  If it is false, then only one thread is
+   running; we will do a real wait, the thread will do something, and
+   we will return that.  */
+
+pid_t
+wait (w)
+    union wait *w;
+{
+  int pid;
+
+  if (!w)
+    return wait3 (0, 0, 0);
+
+  /* Do a real wait if we were told to, or if there are no queued threads.  */
+
+  if (! thread_switch_ok || signal_stack_is_empty ())
+    {
+      int thread;
+
+      pid = wait3 (w, 0, 0);
+
+      if (!WIFSTOPPED (*w) || pid != inferior_pid)
+	return pid;
+
+      /* The inferior has done something and stopped.  Read in all the
+	 threads' registers, and queue up any signals that happened.  */
+
+      if (ioctl (inferior_fd, PIXGETTHCOUNT, &ps) < 0)
+	perror_with_name ("PIXGETTHCOUNT");
+      
+      n_threads = ps.pi_othdcnt;
+      for (thread = 0; thread < n_threads; thread++)
+	{
+	  ps.pi_thread = thread;
+	  if (ioctl (inferior_fd, PIXGETSUBCODE, &ps) < 0)
+	    perror_with_name ("PIXGETSUBCODE");
+	  thread_state[thread] = ps.pi_otstate;
+
+	  if (ps.pi_otstate == PI_TALIVE)
+	    {
+	      select_thread (thread);
+	      ps.pi_buffer = registers;
+	      ps.pi_nbytes = REGISTER_BYTES;
+	      ps.pi_offset = 0;
+	      ps.pi_thread = thread;
+	      if (ioctl (inferior_fd, PIXRDREGS, &ps) < 0)
+		perror_with_name ("PIXRDREGS");
+
+	      registers_fetched ();
+
+	      thread_pc[thread] = read_pc ();
+	      thread_signal[thread] = ps.pi_osigno;
+	      thread_sigcode[thread] = ps.pi_osigcode;
+
+	      /* If the thread's stack has a context frame
+		 on top, something fucked is going on.  I do not
+		 know what, but do I know this: the only thing you
+		 can do with such a thread is continue it.  */
+
+	      thread_is_in_kernel[thread] = 
+		((read_register (PS_REGNUM) >> 25) & 3) == 0;
+
+	      /* Signals push an extended frame and then fault
+		 with a ridiculous pc.  Pop the frame.  */
+
+	      if (thread_pc[thread] > STACK_END_ADDR)
+		{
+		  POP_FRAME;
+		  if (is_break_pc (thread_pc[thread]))
+		    thread_pc[thread] = read_pc () - 2;
+		  else
+		    thread_pc[thread] = read_pc ();
+		  write_register (PC_REGNUM, thread_pc[thread]);
+		}
+	      
+	      if (ps.pi_osigno || ps.pi_osigcode)
+		{
+		  signal_stack++;
+		  signal_stack->pid = pid;
+		  signal_stack->thread = thread;
+		  signal_stack->signo = thread_signal[thread];
+		  signal_stack->subsig = thread_sigcode[thread];
+		  signal_stack->pc = thread_pc[thread];
+		}
+
+	      /* The following hackery is caused by a unix 7.1 feature:
+		 the inferior's fixed scheduling mode is cleared when
+		 it execs the shell (since the shell is not a parallel
+		 program).  So, note the 5.4 trap we get when
+		 the shell does its exec, then catch the 5.0 trap 
+		 that occurs when the debuggee starts, and set fixed
+		 scheduling mode properly.  */
+
+	      if (ps.pi_osigno == 5 && ps.pi_osigcode == 4)
+		exec_trap_timer = 1;
+	      else
+		exec_trap_timer--;
+	      
+	      if (ps.pi_osigno == 5 && exec_trap_timer == 0)
+		set_fixed_scheduling (pid, parallel == 2);
+	    }
+	}
+
+      if (signal_stack_is_empty ())
+	error ("no active threads?!");
+    }
+
+  /* Select the thread that stopped, and return *w saying why.  */
+
+  select_thread (signal_stack->thread);
+
+  stop_signal = signal_stack->signo;
+  stop_sigcode = signal_stack->subsig;
+
+  WSETSTOP (*w, signal_stack->signo);
+  w->w_thread = signal_stack->thread;
+  return (signal_stack--)->pid;
+}
+
+/* Select thread THREAD -- its registers, stack, per-thread memory.
+   This is the only routine that may assign to inferior_thread
+   or thread_regs[].  */
+
+static void
+select_thread (thread)
+     int thread;
+{
+  if (thread == inferior_thread)
+    return;
+
+  bcopy (registers, thread_regs[inferior_thread], REGISTER_BYTES);
+  ps.pi_thread = inferior_thread = thread;
+  if (have_inferior_p ())
+    ioctl (inferior_fd, PISETRWTID, &ps);
+  bcopy (thread_regs[thread], registers, REGISTER_BYTES);
+}
+  
+/* Routine to set or clear a psw bit in the psw and also all psws
+   saved on the stack.  Quits when we get to a frame in which the
+   saved psw is correct. */
+
+static void
+scan_stack (bit, val)
+    long bit, val;
+{
+  long ps = read_register (PS_REGNUM);
+  long fp;
+  if (val ? !(ps & bit) : (ps & bit))
+    {    
+      ps ^= bit;
+      write_register (PS_REGNUM, ps);
+
+      fp = read_register (FP_REGNUM);
+      while (fp & 0x80000000)
+	{
+	  ps = read_memory_integer (fp + 4, 4);
+	  if (val ? (ps & bit) : !(ps & bit))
+	    break;
+	  ps ^= bit;
+	  write_memory (fp + 4, &ps, 4);
+	  fp = read_memory_integer (fp + 8, 4);
+	}
+    }
+}
+
+/* Set fixed scheduling (alliant mode) of process PID to ARG (0 or 1).  */
+
+static void
+set_fixed_scheduling (pid, arg)
+      int arg;
+{
+  struct pattributes pattr;
+  getpattr (pid, &pattr);
+  pattr.pattr_pfixed = arg;
+  setpattr (pid, &pattr);
+}
+
+void
+core_file_command (filename, from_tty)
+     char *filename;
+     int from_tty;
+{
+  int n;
+
+  /* Discard all vestiges of any previous core file
+     and mark data and stack spaces as empty.  */
+
+  if (corefile)
+    free (corefile);
+  corefile = 0;
+
+  if (corechan >= 0)
+    close (corechan);
+  corechan = -1;
+
+  data_start = 0;
+  data_end = 0;
+  stack_start = STACK_END_ADDR;
+  stack_end = STACK_END_ADDR;
+  n_core = 0;
+
+  /* Now, if a new core file was specified, open it and digest it.  */
+
+  if (filename)
+    {
+      filename = tilde_expand (filename);
+      make_cleanup (free, filename);
+      
+      if (have_inferior_p ())
+	error ("To look at a core file, you must kill the inferior with \"kill\".");
+      corechan = open (filename, O_RDONLY, 0);
+      if (corechan < 0)
+	perror_with_name (filename);
+
+      if (myread (corechan, &filehdr, sizeof filehdr) < 0)
+	perror_with_name (filename);
+
+      if (!IS_CORE_SOFF_MAGIC (filehdr.h_magic))
+	error ("%s: not a core file.\n", filename);
+
+      if (myread (corechan, &opthdr, filehdr.h_opthdr) < 0)
+	perror_with_name (filename);
+
+      /* Read through the section headers.
+	 For text, data, etc, record an entry in the core file map.
+	 For context and tcontext, record the file address of
+	 the context blocks.  */
+
+      lseek (corechan, (long) filehdr.h_scnptr, 0);
+
+      n_threads = 0;
+      for (n = 0; n < filehdr.h_nscns; n++)
+	{
+	  if (myread (corechan, &scnhdr, sizeof scnhdr) < 0)
+	    perror_with_name (filename);
+	  if ((scnhdr.s_flags & S_TYPMASK) >= S_TEXT
+	      && (scnhdr.s_flags & S_TYPMASK) <= S_COMON)
+	    {
+	      core_map[n_core].mem_addr = scnhdr.s_vaddr;
+	      core_map[n_core].mem_end = scnhdr.s_vaddr + scnhdr.s_size;
+	      core_map[n_core].file_addr = scnhdr.s_scnptr;
+	      core_map[n_core].type = scnhdr.s_flags & S_TYPMASK;
+	      if (core_map[n_core].type != S_TBSS
+		  && core_map[n_core].type != S_TDATA
+		  && core_map[n_core].type != S_TTEXT)
+		core_map[n_core].thread = -1;
+	      else if (n_core == 0
+		       || core_map[n_core-1].mem_addr != scnhdr.s_vaddr)
+		core_map[n_core].thread = 0;
+	      else 
+		core_map[n_core].thread = core_map[n_core-1].thread + 1;
+	      n_core++;
+	    }
+	  else if ((scnhdr.s_flags & S_TYPMASK) == S_CONTEXT)
+	    context_offset = scnhdr.s_scnptr;
+	  else if ((scnhdr.s_flags & S_TYPMASK) == S_TCONTEXT) 
+	    tcontext_offset[n_threads++] = scnhdr.s_scnptr;
+	}
+
+      /* Read the context block, struct user, struct proc,
+	 and the comm regs.  */
+
+      lseek (corechan, context_offset, 0);
+      if (myread (corechan, &c, sizeof c) < 0)
+	perror_with_name (filename);
+      lseek (corechan, c.core_user_p, 0);
+      if (myread (corechan, &u, sizeof u) < 0)
+	perror_with_name (filename);
+      lseek (corechan, c.core_proc_p, 0);
+      if (myread (corechan, &pr, sizeof pr) < 0)
+	perror_with_name (filename);
+      comm_registers = pr.p_creg;
+
+      /* Core file apparently is really there.  Make it really exist
+	 for xfer_core_file so we can do read_memory on it. */
+
+      if (filename[0] == '/')
+	corefile = savestring (filename, strlen (filename));
+      else
+	corefile = concat (current_directory, "/", filename);
+
+      printf_filtered ("Program %s ", u.u_comm);
+
+      /* Read the thread registers and fill in the thread_xxx[] data.  */
+
+      for (n = 0; n < n_threads; n++)
+	{
+	  select_thread (n);
+
+	  lseek (corechan, tcontext_offset[n], 0);
+	  if (myread (corechan, &tc, sizeof tc) < 0)
+	    perror_with_name (corefile);
+	  lseek (corechan, tc.core_thread_p, 0);
+	  if (myread (corechan, &th, sizeof th) < 0)
+	    perror_with_name (corefile);
+
+	  lseek (corechan, tc.core_syscall_context_p, 0);
+	  if (myread (corechan, registers, REGISTER_BYTES) < 0)
+	    perror_with_name (corefile);
+
+	  thread_signal[n] = th.t_cursig;
+	  thread_sigcode[n] = th.t_code;
+	  thread_state[n] = th.t_state;
+	  thread_pc[n] = read_pc ();
+
+	  if (thread_pc[n] > STACK_END_ADDR)
+	    {
+	      POP_FRAME;
+	      if (is_break_pc (thread_pc[n]))
+		thread_pc[n] = read_pc () - 2;
+	      else
+		thread_pc[n] = read_pc ();
+	      write_register (PC_REGNUM, thread_pc[n]);
+	    }
+
+	  printf_filtered ("thread %d received signal %d, %s\n",
+			   n, thread_signal[n],
+			   thread_signal[n] < NSIG
+			   ? sys_siglist[thread_signal[n]]
+			   : "(undocumented)");
+	}
+
+      /* Select an interesting thread -- also-rans died with SIGKILL,
+	 so find one that didn't.  */
+
+      for (n = 0; n < n_threads; n++)
+	if (thread_signal[n] != 0 && thread_signal[n] != SIGKILL)
+	  {
+	    select_thread (n);
+	    stop_signal = thread_signal[n];
+	    stop_sigcode = thread_sigcode[n];
+	    break;
+	  }
+
+      core_aouthdr.a_magic = 0;
+
+      flush_cached_frames ();
+      set_current_frame (create_new_frame (read_register (FP_REGNUM),
+					     read_pc ()));
+      select_frame (get_current_frame (), 0);
+      validate_files ();
+
+      print_sel_frame (1);
+    }
+  else if (from_tty)
+    printf_filtered ("No core file now.\n");
+}