/*
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.util.logging.Level;
import java.util.logging.Logger;
import org.jpc.emulator.memory.AddressSpace;
/**
*
* @author Ian Preston
*/
public abstract class ProtectedModeExpandDownSegment extends ProtectedModeSegment
{
private static final Logger LOGGING = Logger.getLogger(ProtectedModeSegment.class.getName());
private final int minOffset, maxOffset;
private final int rawLimit;
public ProtectedModeExpandDownSegment(AddressSpace memory, int selector, long descriptor)
{
super(memory, selector, descriptor);
rawLimit = (int) ((descriptor & 0xffffL) | ((descriptor >>> 32) & 0xf0000L));
if (defaultSize)
{
//base = (int) (tmpbase + tmplimit - 0x10000000L);
//limit = 0xFFFFFFFF - tmplimit;
minOffset = (int) (base + limit - 1);
maxOffset = 0xFFFFFFFF;
} else
{
//base = tmpbase + (int) tmplimit - 0x10000;
//limit = 0xFFFF-tmplimit;
minOffset = (int) (base + limit - 1);
maxOffset = 0xFFFF;
}
}
public void checkAddress(int offset)
{
if (((offset < 0) && (maxOffset < 0)) | ((offset > 0) && (maxOffset > 0)))
{
if (offset >= maxOffset)
{
LOGGING.log(Level.INFO, this + "expand down segment: offset not within bounds.");
throw new ProcessorException(ProcessorException.Type.GENERAL_PROTECTION,0,true);
}
} else if (offset > 0)
{
return;
} else
{
LOGGING.log(Level.INFO, this + "expand down segment: offset not within bounds.");
throw new ProcessorException(ProcessorException.Type.GENERAL_PROTECTION,0,true);
}
}
public int getRawLimit()
{
return rawLimit;
}
public boolean setSelector(int selector)
{
throw new IllegalStateException("Cannot set a selector for a Protected Mode segment");
}
static final class ReadWriteDataSegment extends ProtectedModeExpandDownSegment
{
public ReadWriteDataSegment(AddressSpace memory, int selector, long descriptor)
{
super(memory, selector, descriptor);
}
public int getType()
{
return DESCRIPTOR_TYPE_CODE_DATA | TYPE_DATA_WRITABLE;
}
}
}