--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libgomp/config/linux/mutex.c	Fri Jul 17 14:47:48 2009 +0900
@@ -0,0 +1,50 @@
+/* Copyright (C) 2005, 2008, 2009 Free Software Foundation, Inc.
+   Contributed by Richard Henderson <rth@redhat.com>.
+
+   This file is part of the GNU OpenMP Library (libgomp).
+
+   Libgomp 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.
+
+   Libgomp 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/>.  */
+
+/* This is a Linux specific implementation of a mutex synchronization
+   mechanism for libgomp.  This type is private to the library.  This
+   implementation uses atomic instructions and the futex syscall.  */
+
+#include "wait.h"
+
+long int gomp_futex_wake = FUTEX_WAKE | FUTEX_PRIVATE_FLAG;
+long int gomp_futex_wait = FUTEX_WAIT | FUTEX_PRIVATE_FLAG;
+
+void
+gomp_mutex_lock_slow (gomp_mutex_t *mutex)
+{
+  do
+    {
+      int oldval = __sync_val_compare_and_swap (mutex, 1, 2);
+      if (oldval != 0)
+	do_wait (mutex, 2);
+    }
+  while (!__sync_bool_compare_and_swap (mutex, 0, 2));
+}
+
+void
+gomp_mutex_unlock_slow (gomp_mutex_t *mutex)
+{
+  futex_wake (mutex, 1);
+}