1 files changed, 95 insertions, 0 deletions
diff --git a/gcc-4.9/libgcc/config/vxlib.c b/gcc-4.9/libgcc/config/vxlib.c
new file mode 100644
index 000000000..8fddc9a86
--- /dev/null
+++ b/gcc-4.9/libgcc/config/vxlib.c
@@ -0,0 +1,95 @@
+/* Copyright (C) 2002-2014 Free Software Foundation, Inc.
+   Contributed by Zack Weinberg <zack@codesourcery.com>
+
+This file is part of GCC.
+
+GCC 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 3, or (at your option) any later
+version.
+
+GCC 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.
+
+Under Section 7 of GPL version 3, you are granted additional
+permissions described in the GCC Runtime Library Exception, version
+3.1, as published by the Free Software Foundation.
+
+You should have received a copy of the GNU General Public License and
+a copy of the GCC Runtime Library Exception along with this program;
+see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+<http://www.gnu.org/licenses/>.  */
+
+/* Threads compatibility routines for libgcc2 for VxWorks.
+   These are out-of-line routines called from gthr-vxworks.h.  */
+
+#include "tconfig.h"
+#include "tsystem.h"
+#include "gthr.h"
+
+#if defined(__GTHREADS)
+#include <vxWorks.h>
+#ifndef __RTP__
+#include <vxLib.h>
+#endif
+#include <taskLib.h>
+#ifndef __RTP__
+#include <taskHookLib.h>
+#else
+# include <errno.h>
+#endif
+
+/* Init-once operation.
+
+   This would be a clone of the implementation from gthr-solaris.h,
+   except that we have a bootstrap problem - the whole point of this
+   exercise is to prevent double initialization, but if two threads
+   are racing with each other, once->mutex is liable to be initialized
+   by both.  Then each thread will lock its own mutex, and proceed to
+   call the initialization routine.
+
+   So instead we use a bare atomic primitive (vxTas()) to handle
+   mutual exclusion.  Threads losing the race then busy-wait, calling
+   taskDelay() to yield the processor, until the initialization is
+   completed.  Inefficient, but reliable.  */
+
+int
+__gthread_once (__gthread_once_t *guard, void (*func)(void))
+{
+  if (guard->done)
+    return 0;
+
+#ifdef __RTP__
+  __gthread_lock_library ();
+#else
+  while (!vxTas ((void *)&guard->busy))
+    {
+#ifdef __PPC__
+      /* This can happen on powerpc, which is using all 32 bits
+	 of the gthread_once_t structure.  */
+      if (guard->done)
+	return;
+#endif
+      taskDelay (1);
+    }
+#endif
+
+  /* Only one thread at a time gets here.  Check ->done again, then
+     go ahead and call func() if no one has done it yet.  */
+  if (!guard->done)
+    {
+      func ();
+      guard->done = 1;
+    }
+
+#ifdef __RTP__
+  __gthread_unlock_library ();
+#else
+  guard->busy = 0;
+#endif
+  return 0;
+}
+
+#endif /* __GTHREADS */