1 /*
   2  * Copyright 2001 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  20  * CA 95054 USA or visit www.sun.com if you need additional information or
  21  * have any questions.
  22  *
  23  */
  24 
  25 package sun.jvm.hotspot.debugger.cdbg.basic.x86;
  26 
  27 import sun.jvm.hotspot.debugger.*;
  28 import sun.jvm.hotspot.debugger.cdbg.*;
  29 import sun.jvm.hotspot.debugger.cdbg.basic.*;
  30 
  31 /** Basic X86 frame functionality providing sender() functionality. */
  32 
  33 public class X86CFrame extends BasicCFrame {
  34   private Address ebp;
  35   private Address pc;
  36 
  37   private static final int ADDRESS_SIZE = 4;
  38 
  39   /** Constructor for topmost frame */
  40   public X86CFrame(CDebugger dbg, Address ebp, Address pc) {
  41     super(dbg);
  42     this.ebp = ebp;
  43     this.pc  = pc;
  44   }
  45 
  46   public CFrame sender() {
  47     if (ebp == null) {
  48       return null;
  49     }
  50 
  51     Address nextEBP = ebp.getAddressAt( 0 * ADDRESS_SIZE);
  52     if (nextEBP == null) {
  53       return null;
  54     }
  55     Address nextPC  = ebp.getAddressAt( 1 * ADDRESS_SIZE);
  56     if (nextPC == null) {
  57       return null;
  58     }
  59     return new X86CFrame(dbg(), nextEBP, nextPC);
  60   }
  61 
  62   public Address pc() {
  63     return pc;
  64   }
  65 
  66   public Address localVariableBase() {
  67     return ebp;
  68   }
  69 }