processorexception.java

JPC: x86 PC Hardware Emulator. 牛津大学开发的一个纯JAVA的x86系统结构硬件模拟器。

/*
    JPC: A x86 PC Hardware Emulator for a pure Java Virtual Machine
    Release Version 2.0

    A project from the Physics Dept, The University of Oxford

    Copyright (C) 2007 Isis Innovation Limited

    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: 

    www.physics.ox.ac.uk/jpc
*/

package org.jpc.emulator.processor;

public final class ProcessorException extends RuntimeException
{
    private int vector;
    private int errorCode;
    private boolean pointsToSelf;
    private boolean hasErrorCode;

    public ProcessorException(int vector, int errorCode, boolean pointsToSelf)
    {
        this.vector = vector;
        this.hasErrorCode = true;
        this.errorCode = errorCode;
        this.pointsToSelf = pointsToSelf;
    }

    public ProcessorException(int vector, boolean pointsToSelf)
    {
        this.vector = vector;
        this.hasErrorCode = false;
        this.errorCode = 0;
        this.pointsToSelf = pointsToSelf;
    }
    
    public int getVector()
    {
        return vector;
    }
    
    public boolean hasErrorCode()
    {
        return hasErrorCode;
    }
    
    public int getErrorCode()
    {
	    return errorCode;
    }
    
    public boolean pointsToSelf()
    {
        return pointsToSelf;
    }

    private static final boolean isContributory(int vector)
    {
	switch (vector) {
	case Processor.PROC_EXCEPTION_DE:
	case Processor.PROC_EXCEPTION_TS:
	case Processor.PROC_EXCEPTION_NP:
	case Processor.PROC_EXCEPTION_SS:
	case Processor.PROC_EXCEPTION_GP:
	    return true;
	default:
	    return false;
	}
    }

    private static final boolean isPageFault(int vector)
    {
	return (vector == Processor.PROC_EXCEPTION_PF);
    }

    public boolean combinesToDoubleFault(int vector)
    {
	//Here we are the "second exception"
	return isContributory(vector) && isContributory(this.getVector()) ||
	    isPageFault(vector) && (isContributory(this.getVector()) || isPageFault(this.getVector()));
    }

    public String toString()
    {
	if (hasErrorCode())
	    return "Processor Exception: " + getVector() + " [errorcode:0x" + Integer.toHexString(getErrorCode()) + "]";
	else
	    return "Processor Exception: " + getVector();
    }
}