/*
JPC: An x86 PC Hardware Emulator for a pure Java Virtual Machine
Release Version 2.4
A project from the Physics Dept, The University of Oxford
Copyright (C) 2007-2010 The University of Oxford
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License version 2 as published by
the Free Software Foundation.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
Details (including contact information) can be found at:
jpc.sourceforge.net
or the developer website
sourceforge.net/projects/jpc/
Conceived and Developed by:
Rhys Newman, Ian Preston, Chris Dennis
End of licence header
*/
package org.jpc.emulator.processor;
import java.io.DataOutput;
import java.io.IOException;
import org.jpc.emulator.memory.AddressSpace;
/**
*
* @author Ian Preston
*/
public class Virtual8086ModeSegment extends Segment {
private int selector;
private int base;
private int type;
private int dpl, rpl;
private long limit;
public Virtual8086ModeSegment(AddressSpace memory, int selector, boolean isCode)
{
super(memory);
this.selector = selector;
base = selector << 4;
limit = 0xffffL;
dpl = 3;
rpl = 3;
if (isCode)
type = ProtectedModeSegment.TYPE_CODE | ProtectedModeSegment.TYPE_CODE_READABLE | ProtectedModeSegment.TYPE_ACCESSED;
else
type = ProtectedModeSegment.TYPE_DATA_WRITABLE | ProtectedModeSegment.TYPE_ACCESSED;
}
public Virtual8086ModeSegment(AddressSpace memory, Segment ancestor)
{
super(memory);
selector = ancestor.getSelector();
base = ancestor.getBase();
type = ancestor.getType();
limit = 0xffffffffL & ancestor.getLimit();
}
public void saveState(DataOutput output) throws IOException
{
output.writeInt(1);
output.writeInt(selector);
if (type == (ProtectedModeSegment.TYPE_CODE | ProtectedModeSegment.TYPE_CODE_READABLE | ProtectedModeSegment.TYPE_ACCESSED))
output.writeBoolean(true);
else
output.writeBoolean(false);
output.writeInt(rpl);
}
public boolean getDefaultSizeFlag()
{
return false;
}
public int getLimit()
{
return (int)limit;
}
public int getBase()
{
return base;
}
public int getSelector()
{
return selector;
}
public boolean setSelector(int selector)
{
this.selector = selector;
base = selector << 4;
type = ProtectedModeSegment.TYPE_DATA_WRITABLE | ProtectedModeSegment.TYPE_ACCESSED;
return true;
}
public void checkAddress(int offset)
{
if ((0xffffffffL & offset) > limit)
throw ProcessorException.GENERAL_PROTECTION_0;
}
public int translateAddressRead(int offset)
{
checkAddress(offset);
return base + offset;
}
public int translateAddressWrite(int offset)
{
checkAddress(offset);
return base + offset;
}
public int getRPL()
{
return rpl;
}
public int getType()
{
return type;
}
public boolean isPresent()
{
return true;
}
public boolean isSystem()
{
return false;
}
public int getDPL()
{
return dpl;
}
public void setRPL(int cpl)
{
rpl = cpl;
}
public void printState()
{
System.out.println("VM86 Segment");
System.out.println("selector: " + Integer.toHexString(selector));
System.out.println("base: " + Integer.toHexString(base));
System.out.println("dpl: " + Integer.toHexString(dpl));
System.out.println("rpl: " + Integer.toHexString(rpl));
System.out.println("limit: " + Long.toHexString(limit));
System.out.println("type: " + Integer.toHexString(type));
}
}