+ * Copyright (c) 1991-1994 by Xerox Corporation. All rights reserved.
+ * Copyright (c) 1996-1999 by Silicon Graphics. All rights reserved.
+ * Copyright (c) 1999-2004 Hewlett-Packard Development Company, L.P.
+ * Copyright (c) 2009-2015 Mathieu Desnoyers
+ * Copyright (c) 2010 Paul E. McKenney, IBM Corporation
+ * (Adapted from uatomic_arch_ppc.h)