--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/runtime/prefetch.hpp	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,44 @@
+/*
+ * Copyright 2003 Sun Microsystems, Inc.  All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code 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
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ */
+
+// If calls to prefetch methods are in a loop, the loop should be cloned
+// such that if Prefetch{Scan,Copy}Interval and/or PrefetchFieldInterval
+// say not to do prefetching, these methods aren't called.  At the very
+// least, they take up a memory issue slot.  They should be implemented
+// as inline assembly code: doing an actual call isn't worth the cost.
+
+class Prefetch : AllStatic {
+ public:
+  enum style {
+    do_none,  // Do no prefetching
+    do_read,  // Do read prefetching
+    do_write  // Do write prefetching
+  };
+
+  // Prefetch anticipating read; must not fault, semantically a no-op
+  static void read(void* loc, intx interval);
+
+  // Prefetch anticipating write; must not fault, semantically a no-op
+  static void write(void* loc, intx interval);
+};