org/jpc/emulator/memory/codeblock/SpanningProtectedModeCodeBlock.java

   1 /*
   2     JPC-RR: A x86 PC Hardware Emulator
   3     Release 1
   4
   5     Copyright (C) 2007-2009 Isis Innovation Limited
   6     Copyright (C) 2009 H. Ilari Liusvaara
   7
   8     This program is free software; you can redistribute it and/or modify
   9     it under the terms of the GNU General Public License version 2 as published by
  10     the Free Software Foundation.
  11
  12     This program is distributed in the hope that it will be useful,
  13     but WITHOUT ANY WARRANTY; without even the implied warranty of
  14     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15     GNU General Public License for more details.
  16
  17     You should have received a copy of the GNU General Public License along
  18     with this program; if not, write to the Free Software Foundation, Inc.,
  19     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  20
  21     Based on JPC x86 PC Hardware emulator,
  22     A project from the Physics Dept, The University of Oxford
  23
  24     Details about original JPC can be found at:
  25
  26     www-jpc.physics.ox.ac.uk
  27
  28 */
  29
  30 package org.jpc.emulator.memory.codeblock;
  31
  32 import org.jpc.emulator.processor.Processor;
  33 import org.jpc.emulator.memory.AddressSpace;
  34
  35 /**
  36  *
  37  * @author Chris Dennis
  38  */
  39 class SpanningProtectedModeCodeBlock extends SpanningCodeBlock implements ProtectedModeCodeBlock
  40 {
  41     private ByteSourceWrappedMemory byteSource = new ByteSourceWrappedMemory();
  42
  43     private CodeBlockFactory[] factories;
  44     private int length;
  45
  46     public SpanningProtectedModeCodeBlock(CodeBlockFactory[] factories)
  47     {
  48         this.factories = factories;
  49     }
  50
  51     public int getX86Length()
  52     {
  53         return length;
  54     }
  55
  56     protected CodeBlock decode(Processor cpu)
  57     {
  58         ProtectedModeCodeBlock block = null;
  59         AddressSpace memory = cpu.linearMemory;
  60         int address = cpu.getInstructionPointer();
  61         boolean opSize = cpu.cs.getDefaultSizeFlag();
  62         for(int i = 0; (i < factories.length) && (block == null); i++)
  63             try {
  64                 byteSource.set(memory, address);
  65                 block = factories[i].getProtectedModeCodeBlock(byteSource, opSize);
  66             } catch (IllegalStateException e) {
  67             }
  68         length = block.getX86Length();
  69         byteSource.set(null, 0);
  70         return block;
  71     }
  72
  73     public String toString()
  74     {
  75         return "Spanning Protected Mode CodeBlock";
  76     }
  77 }