1 /*
2 * Copyright (c) 2001, Zoltan Farkas All Rights Reserved.
3 *
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation; either
7 * version 2.1 of the License, or (at your option) any later version.
8 *
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
17 */
18
19 package net.sf.zel.instr;
20
21 import net.sf.zel.vm.*;
22
23 /**
24 * <p>Title: CTXCHG</p>
25 * <p>Description: Exchanges the currect mem context with the one from
26 * the top of the context stack</p>
27 */
28 public final class CTXCHG extends Instruction
29 {
30 private static final long serialVersionUID = -690448906848594522L;
31
32 private CTXCHG(){};
33
34 /**
35 * mem ctxchanger instruction microcode
36 * @param context ExecutionContext
37 * @throws VMException
38 */
39 public void execute(ExecutionContext context)
40 {
41 final Object tmp = context.memContext;
42 context.memContext = (java.util.Map) context.memContextStack.pop();
43 context.memContextStack.push(tmp);
44 context.ip++;
45 }
46 /**
47 * instance
48 */
49 public static final Instruction instance = new CTXCHG();
50 }