1 /* 2 * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 package sun.jvm.hotspot.gc.z; 26 27 import sun.jvm.hotspot.debugger.Address; 28 import sun.jvm.hotspot.debugger.OopHandle; 29 import sun.jvm.hotspot.runtime.VM; 30 31 class ZOop { 32 private static final long MSB = ~0L ^ (~0L >>> 1); 33 34 private static Address msbAddress() { 35 return VM.getVM().getUniverse().heap().start().orWithMask(MSB).andWithMask(MSB); 36 } 37 38 static Address to_address(long value) { 39 // If the value of an Address becomes 0, null is returned instead of an Address. 40 // Start with a one-bit address and as a last step, remove that bit. 41 Address oneAddress = msbAddress(); 42 return oneAddress.orWithMask(value).xorWithMask(ZAddress.as_long(oneAddress)); 43 } 44 45 static Address to_address(OopHandle oop) { 46 return to_address(ZAddress.as_long(oop)); 47 } 48 }