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comparison graal/com.oracle.max.asmdis/src/com/sun/max/asm/OffsetLiteral.java @ 3733:e233f5660da4

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Added Java files from Maxine project.
author Thomas Wuerthinger <thomas.wuerthinger@oracle.com>
date Sat, 17 Dec 2011 19:59:18 +0100
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3732:3e2e8b8abdaf 3733:e233f5660da4
1 /*
2 * Copyright (c) 2007, 2011, 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 package com.sun.max.asm;
24
25 /**
26 * Represents an offset between two positions (represented by given labels) in the assembled code.
27 */
28 public class OffsetLiteral extends MutableAssembledObject {
29
30 /**
31 * Creates an offset between two positions (represented by given labels) in the assembled code.
32 *
33 * @param base the label whose position marks the base of the offset
34 * @param target the label whose position marks the target of the offset
35 */
36 protected OffsetLiteral(Assembler assembler, int startPosition, int endPosition, Label target, Label base) {
37 super(assembler, startPosition, endPosition);
38 assembler.addFixedSizeAssembledObject(this);
39 this.target = target;
40 this.base = base;
41 }
42
43 private final Label target;
44 private final Label base;
45
46 @Override
47 protected final void assemble() throws AssemblyException {
48 final Assembler assembler = assembler();
49 final long offset = offset();
50 // select the correct assembler function to emit the offset.
51 // The assembler knows the endianness to use
52 switch(size()) {
53 case 1:
54 assembler.emitByte((byte) (offset & 0xFF));
55 break;
56 case 2:
57 assembler.emitShort((short) (offset & 0xFFFF));
58 break;
59 case 4:
60 assembler.emitInt((int) (offset & 0xFFFFFFFF));
61 break;
62 case 8:
63 assembler.emitLong(offset);
64 break;
65 default:
66 throw new AssemblyException("Invalid size for offset literal");
67 }
68 }
69
70 public final long offset() throws AssemblyException {
71 return target.position() - base.position();
72 }
73
74 public final boolean isCode() {
75 return false;
76 }
77 }