--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/com.oracle.max.asmdis/src/com/sun/max/asm/gen/cisc/x86/X86Opcode.java	Sat Dec 17 19:59:18 2011 +0100
@@ -0,0 +1,70 @@
+/*
+ * Copyright (c) 2007, 2011, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package com.sun.max.asm.gen.cisc.x86;
+
+import static com.sun.max.asm.gen.cisc.x86.HexByte.*;
+
+/**
+ * x86 instruction prefix bytes.
+ */
+public final class X86Opcode {
+
+    private X86Opcode() {
+    }
+
+    public static final HexByte SEG_ES = _26;
+    public static final HexByte SEG_SS = _36;
+    public static final HexByte SEG_CS = _2E;
+    public static final HexByte SEG_DS = _3E;
+    public static final HexByte REX_MIN = _40;
+    public static final HexByte REX_MAX = _4F;
+    public static final HexByte SEG_FS = _64;
+    public static final HexByte SEG_GS = _65;
+    public static final HexByte OPERAND_SIZE = _66;
+    public static final HexByte ADDRESS_SIZE = _67;
+    public static final HexByte FWAIT = _9B;
+    public static final HexByte LOCK = _F0;
+    public static final HexByte REPNE = _F2;
+    public static final HexByte REPE = _F3;
+
+    public static boolean isRexPrefix(HexByte opcode) {
+        return X86Opcode.REX_MIN.ordinal() <= opcode.ordinal() && opcode.ordinal() <= X86Opcode.REX_MAX.ordinal();
+    }
+
+    public static boolean isFloatingPointEscape(HexByte opcode) {
+        switch (opcode) {
+            case _D8:
+            case _D9:
+            case _DA:
+            case _DB:
+            case _DC:
+            case _DD:
+            case _DE:
+            case _DF:
+                return true;
+            default:
+                return false;
+        }
+    }
+
+}