compiles with -Xlint

Makefile

+# makefile for SSM, Simple Stack Machine
+
+default: ssm
+
+DIR_SRC			:= src
+DIR_HELP		:= Help
+DIR_IMGS		:= Images
+DIR_BLD			:= build
+DIR_BLD_JAR		:= build/ssm
+
+SSM_JAR			:= $(DIR_BLD)/ssm.jar
+SSM_SRC			:= $(wildcard $(DIR_SRC)/nl/uu/cs/ssm/*.java) $(wildcard $(DIR_SRC)/nl/uu/cs/ssmui/*.java)
+SSM_SRC_HELP	:= $(wildcard $(DIR_SRC)/$(DIR_HELP)/*.prop)
+SSM_SRC_IMGS	:= $(wildcard $(DIR_SRC)/$(DIR_IMGS)/*.gif) $(wildcard $(DIR_SRC)/$(DIR_IMGS)/*.GIF)
+SSM_MKF			:= Makefile
+
+JAVAC_OPTS		:= -Xlint
+
+ssm: $(SSM_JAR)
+
+$(SSM_JAR): $(SSM_SRC) $(SSM_SRC_HELP) $(SSM_SRC_IMGS) $(SSM_MKF)
+	mkdir -p $(DIR_BLD_JAR) $(DIR_BLD_JAR)/$(DIR_HELP) $(DIR_BLD_JAR)/$(DIR_IMGS)
+	cp $(SSM_SRC_HELP) $(DIR_BLD_JAR)/$(DIR_HELP)
+	cp $(SSM_SRC_IMGS) $(DIR_BLD_JAR)/$(DIR_IMGS)
+	javac $(JAVAC_OPTS) -d $(DIR_BLD_JAR) $(SSM_SRC) && \
+	cd $(DIR_BLD_JAR) && \
+	jar cf ../$(@F) .

src/nl/uu/cs/ssm/HelpSupplier.java

-/**
 * Simple Stack Machine
 *
 * Written by Atze Dijkstra, atze@cs.uu.nl,
 * Copyright Utrecht University.
 *
 */
package nl.uu.cs.ssm ;
import java.util.* ;
public interface HelpSupplier{
    public Enumeration getTopics() ;
    
    public String getHelpSupplierName() ;
    
    public String getShortSummaryForTopic( String topic ) ;
    
    public void getHelpForTopic( String topic, HelpAccumulator acc ) ;
    }
\ No newline at end of file
+/**
 * Simple Stack Machine
 *
 * Written by Atze Dijkstra, atze@cs.uu.nl,
 * Copyright Utrecht University.
 *
 */
package nl.uu.cs.ssm ;
import java.util.* ;
public interface HelpSupplier{
    public Enumeration<String> getTopics() ;
    
    public String getHelpSupplierName() ;
    
    public String getShortSummaryForTopic( String topic ) ;
    
    public void getHelpForTopic( String topic, HelpAccumulator acc ) ;
    }
\ No newline at end of file

src/nl/uu/cs/ssm/MachineStateEvent.java

@@ -12,9 +12,11 @@ import java.util.* ;
 
 public class MachineStateEvent extends UndoableEvent
 {
+	private static final long serialVersionUID = 1L ;
+
     protected MachineStateEvent( Object src, Modification mdf )
     {
         super( src, mdf ) ;
     }
     
-}
\ No newline at end of file
+}

src/nl/uu/cs/ssm/Memory.java

-/**
 * Simple Stack Machine
 *
 * Written by Atze Dijkstra, atze@cs.uu.nl,
 * Copyright Utrecht University.
 *
 */
package nl.uu.cs.ssm ;
import java.util.* ;
public class Memory extends AbstractMemoryCellModel
	implements MemoryCellModel{
    private int             cells[]         ;
    private Hashtable       annotations     ;
    private int             nUsedForCode    ;
    
    private Messenger messenger             ;
    
    protected Memory( int initCapacity, Messenger m )
    {
        messenger = m ;
        cells = new int[ initCapacity ] ;
        for ( int i = 0 ; i < cells.length ; i++ )
            cells[ i ] = 0 ;
        reset() ;
    }
    
    public void reset()
    {
    	nUsedForCode = 0 ;
    	annotations = new Hashtable() ;
        for ( int i = 0 ; i < cells.length ; i++ )
            setAt( i, 0 ) ;
    }
    
    public int getCapacity()
    {
        return cells.length ;
    }
    
    public int getUsedForCode()
    {
        return nUsedForCode ;
    }
    
    private boolean checkWithinMemory( int addr )
    {
        boolean res ;
        if ( res = ( addr < 0 || addr >= cells.length ) )
        {
            messenger.println
            	( java.text.MessageFormat.format
            		( "attempt to access location {0} outside {1}"
            		, new Object[] { Utils.asHex(addr), ""+this }
            		) ) ;
        }
        return ! res ;
    }
    
    class UndoMemoryModification implements Modification
    {
    	private int offset, value ;
    	
    	UndoMemoryModification( int o, int v )
    	{
    		offset = o ;
    		value = v ;
    	}
    	
    	public void modify()
    	{
    		setAt( offset, value ) ;
    	}
    }
    
    public void setAt( int addr, int v )
    {
        if ( checkWithinMemory( addr ) )
        {
            int oldv = cells[ addr ] ;
            cells[ addr ] = v ;
            fireCellChange( this, addr, oldv, new UndoMemoryModification( addr, oldv ) ) ;
        }
    }
    
    public void setAt( int addr, String v )
    {
        setAt( addr, Utils.fromHex( v ) ) ;
    }
    
    public int getAt( int addr )
    {
        int res = 0 ;
        if ( checkWithinMemory( addr ) )
        {
            res = cells[ addr ] ;
        }
        return res ;
    }
    
    public int[] getAt( int addr, int len )
    {
        int res[] = new int[ len ] ;
        for ( int i = 0 ; i < len && checkWithinMemory( addr + i ) ; i++ )
        {
            res[ i ] = cells[ addr + i ] ;
        }
        return res ;
    }
    
    public String getAsHexAt( int addr )
    {
        return Utils.asHex( getAt( addr ) ) ;
    }
    
    class UndoAnnotationModification implements Modification
    {
    	private int offset ;
    	private MemoryAnnotation value ;
    	
    	UndoAnnotationModification( int o, MemoryAnnotation v )
    	{
    		offset = o ;
    		value = v ;
    	}
    	
    	public void modify()
    	{
    		setAnnotationAt( offset, value ) ;
    	}
    }
    
    public void setAnnotationAt( int addr, MemoryAnnotation v )
    {
        if ( checkWithinMemory( addr ) )
        {
            //System.out.println( "mem set annote at " + addr + "=" + v ) ;
            Integer a = new Integer( addr ) ;
            Object oldv ;
            if ( v != null )
                oldv = annotations.put( a, v ) ;
            else
                oldv = annotations.remove( a ) ;
            if ( oldv != v )
                fireCellChange( this, addr, (MemoryAnnotation)oldv, new UndoAnnotationModification( addr, (MemoryAnnotation)oldv ) ) ;
        }
    }
    
    public MemoryAnnotation getAnnotationAt( int addr )
    {
        MemoryAnnotation res ;
        res = (MemoryAnnotation)annotations.get( new Integer(addr) ) ;
        //System.out.println( "mem got annote at " + addr + "=" + res ) ;
        return res ;
    }
    
    public void ensureCapacity( int nCells )
    {
        if ( nCells > (cells.length - nUsedForCode) )
        {
            int newCells[] = new int[ 2 * (nCells + 10) + cells.length ] ;
            System.arraycopy( cells, 0, newCells, 0, cells.length ) ;
            cells = newCells ;
        }
    }
    
    public void deleteAt( int pos, int n )
    {
        for( int i = pos + n ; i < nUsedForCode ; i++ )
            cells[ i-n ] = cells[ i ] ;
        nUsedForCode -= n ;
    }
    
    public void reserveAt( int pos, int n )
    {
        ensureCapacity( n ) ;
        for( int i = nUsedForCode - 1 ; i >= pos ; i-- )
        {
            cells[ i+n ] = cells[ i ] ;
        }
        for( int i = 0 ; i < n ; i++ )
            cells[ i+pos ] = 0 ;
        nUsedForCode += n ;
    }
    
    public void shiftAt( int pos, int n )
    {
        if ( n > 0 )
            reserveAt( pos, n ) ;
        else if ( n < 0 )
            deleteAt( pos, -n ) ;
    }
    
    public void copyAt( int pos, int[] vals )
    {
        for( int i = 0 ; i < vals.length ; i++ )
            cells[ i+pos ] = vals[ i ] ;
    }
    
    public void insertAt( int pos, int[] vals )
    {
        reserveAt( pos, vals.length ) ;
        copyAt( pos, vals ) ;
    }
    
    public String toString()
    {
    	return "memory [0(" + Utils.asHex(nUsedForCode,false) + ").." +  Utils.asHex(getCapacity()-1,false) + "]" ;
    }
    
}
\ No newline at end of file
+/**
 * Simple Stack Machine
 *
 * Written by Atze Dijkstra, atze@cs.uu.nl,
 * Copyright Utrecht University.
 *
 */
package nl.uu.cs.ssm ;
import java.util.* ;
public class Memory extends AbstractMemoryCellModel
	implements MemoryCellModel{
    private int             cells[]         ;
    private Hashtable<Integer,Object>       annotations     ;
    private int             nUsedForCode    ;
    
    private Messenger messenger             ;
    
    protected Memory( int initCapacity, Messenger m )
    {
        messenger = m ;
        cells = new int[ initCapacity ] ;
        for ( int i = 0 ; i < cells.length ; i++ )
            cells[ i ] = 0 ;
        reset() ;
    }
    
    public void reset()
    {
    	nUsedForCode = 0 ;
    	annotations = new Hashtable<Integer,Object>() ;
        for ( int i = 0 ; i < cells.length ; i++ )
            setAt( i, 0 ) ;
    }
    
    public int getCapacity()
    {
        return cells.length ;
    }
    
    public int getUsedForCode()
    {
        return nUsedForCode ;
    }
    
    private boolean checkWithinMemory( int addr )
    {
        boolean res ;
        if ( res = ( addr < 0 || addr >= cells.length ) )
        {
            messenger.println
            	( java.text.MessageFormat.format
            		( "attempt to access location {0} outside {1}"
            		, new Object[] { Utils.asHex(addr), ""+this }
            		) ) ;
        }
        return ! res ;
    }
    
    class UndoMemoryModification implements Modification
    {
    	private int offset, value ;
    	
    	UndoMemoryModification( int o, int v )
    	{
    		offset = o ;
    		value = v ;
    	}
    	
    	public void modify()
    	{
    		setAt( offset, value ) ;
    	}
    }
    
    public void setAt( int addr, int v )
    {
        if ( checkWithinMemory( addr ) )
        {
            int oldv = cells[ addr ] ;
            cells[ addr ] = v ;
            fireCellChange( this, addr, oldv, new UndoMemoryModification( addr, oldv ) ) ;
        }
    }
    
    public void setAt( int addr, String v )
    {
        setAt( addr, Utils.fromHex( v ) ) ;
    }
    
    public int getAt( int addr )
    {
        int res = 0 ;
        if ( checkWithinMemory( addr ) )
        {
            res = cells[ addr ] ;
        }
        return res ;
    }
    
    public int[] getAt( int addr, int len )
    {
        int res[] = new int[ len ] ;
        for ( int i = 0 ; i < len && checkWithinMemory( addr + i ) ; i++ )
        {
            res[ i ] = cells[ addr + i ] ;
        }
        return res ;
    }
    
    public String getAsHexAt( int addr )
    {
        return Utils.asHex( getAt( addr ) ) ;
    }
    
    class UndoAnnotationModification implements Modification
    {
    	private int offset ;
    	private MemoryAnnotation value ;
    	
    	UndoAnnotationModification( int o, MemoryAnnotation v )
    	{
    		offset = o ;
    		value = v ;
    	}
    	
    	public void modify()
    	{
    		setAnnotationAt( offset, value ) ;
    	}
    }
    
    public void setAnnotationAt( int addr, MemoryAnnotation v )
    {
        if ( checkWithinMemory( addr ) )
        {
            //System.out.println( "mem set annote at " + addr + "=" + v ) ;
            Integer a = new Integer( addr ) ;
            Object oldv ;
            if ( v != null )
                oldv = annotations.put( a, v ) ;
            else
                oldv = annotations.remove( a ) ;
            if ( oldv != v )
                fireCellChange( this, addr, (MemoryAnnotation)oldv, new UndoAnnotationModification( addr, (MemoryAnnotation)oldv ) ) ;
        }
    }
    
    public MemoryAnnotation getAnnotationAt( int addr )
    {
        MemoryAnnotation res ;
        res = (MemoryAnnotation)annotations.get( new Integer(addr) ) ;
        //System.out.println( "mem got annote at " + addr + "=" + res ) ;
        return res ;
    }
    
    public void ensureCapacity( int nCells )
    {
        if ( nCells > (cells.length - nUsedForCode) )
        {
            int newCells[] = new int[ 2 * (nCells + 10) + cells.length ] ;
            System.arraycopy( cells, 0, newCells, 0, cells.length ) ;
            cells = newCells ;
        }
    }
    
    public void deleteAt( int pos, int n )
    {
        for( int i = pos + n ; i < nUsedForCode ; i++ )
            cells[ i-n ] = cells[ i ] ;
        nUsedForCode -= n ;
    }
    
    public void reserveAt( int pos, int n )
    {
        ensureCapacity( n ) ;
        for( int i = nUsedForCode - 1 ; i >= pos ; i-- )
        {
            cells[ i+n ] = cells[ i ] ;
        }
        for( int i = 0 ; i < n ; i++ )
            cells[ i+pos ] = 0 ;
        nUsedForCode += n ;
    }
    
    public void shiftAt( int pos, int n )
    {
        if ( n > 0 )
            reserveAt( pos, n ) ;
        else if ( n < 0 )
            deleteAt( pos, -n ) ;
    }
    
    public void copyAt( int pos, int[] vals )
    {
        for( int i = 0 ; i < vals.length ; i++ )
            cells[ i+pos ] = vals[ i ] ;
    }
    
    public void insertAt( int pos, int[] vals )
    {
        reserveAt( pos, vals.length ) ;
        copyAt( pos, vals ) ;
    }
    
    public String toString()
    {
    	return "memory [0(" + Utils.asHex(nUsedForCode,false) + ").." +  Utils.asHex(getCapacity()-1,false) + "]" ;
    }
    
}
\ No newline at end of file

src/nl/uu/cs/ssm/MemoryCellEvent.java

-/**
 * Simple Stack Machine
 *
 * Written by Atze Dijkstra, atze@cs.uu.nl,
 * Copyright Utrecht University.
 *
 */
package nl.uu.cs.ssm ;
import java.util.* ;
public class MemoryCellEvent extends UndoableEvent{
    public static final int CELL        = 0 ;
    public static final int ANNOTATION  = 1 ;
    
    public int      		cellIndex       	;
    public Object   		oldCellValue    	;
    public int      		event          		;
    
    protected MemoryCellEvent( Object src, int which, int previous, Modification mdf )
    {
        super( src, mdf ) ;
        event = CELL ;
        cellIndex = which ;
        oldCellValue = new Integer( previous ) ;
    }
    
    protected MemoryCellEvent( Object src, int which, MemoryAnnotation previous, Modification mdf )
    {
        super( src, mdf ) ;
        event = ANNOTATION ;
        cellIndex = which ;
        oldCellValue = previous ;
    }
    
    public int getCellIndex()
    {
        return cellIndex ;
    }
    
    public int getOldCellValue()
    {
        return ((Integer)oldCellValue).intValue() ;
    }
    
    public MemoryAnnotation getOldAnnotation()
    {
        return (MemoryAnnotation)oldCellValue ;
    }
    
    public String toString()
    {
    	return "MemCellEvent src=" + getSource() + " inx=" + cellIndex + " prev=" + oldCellValue ;
    }}
\ No newline at end of file
+/**
 * Simple Stack Machine
 *
 * Written by Atze Dijkstra, atze@cs.uu.nl,
 * Copyright Utrecht University.
 *
 */
package nl.uu.cs.ssm ;
import java.util.* ;
public class MemoryCellEvent extends UndoableEvent{
	private static final long serialVersionUID = 1L ;

    public static final int CELL        = 0 ;
    public static final int ANNOTATION  = 1 ;
    
    public int      		cellIndex       	;
    public Object   		oldCellValue    	;
    public int      		event          		;
    
    protected MemoryCellEvent( Object src, int which, int previous, Modification mdf )
    {
        super( src, mdf ) ;
        event = CELL ;
        cellIndex = which ;
        oldCellValue = new Integer( previous ) ;
    }
    
    protected MemoryCellEvent( Object src, int which, MemoryAnnotation previous, Modification mdf )
    {
        super( src, mdf ) ;
        event = ANNOTATION ;
        cellIndex = which ;
        oldCellValue = previous ;
    }
    
    public int getCellIndex()
    {
        return cellIndex ;
    }
    
    public int getOldCellValue()
    {
        return ((Integer)oldCellValue).intValue() ;
    }
    
    public MemoryAnnotation getOldAnnotation()
    {
        return (MemoryAnnotation)oldCellValue ;
    }
    
    public String toString()
    {
    	return "MemCellEvent src=" + getSource() + " inx=" + cellIndex + " prev=" + oldCellValue ;
    }}
\ No newline at end of file

src/nl/uu/cs/ssm/MetaInstruction.java

-/**
 * Simple Stack Machine
 *
 * Written by Atze Dijkstra, atze@cs.uu.nl,
 * Copyright Utrecht University.
 *
 */
package nl.uu.cs.ssm ;
import java.util.* ;import java.awt.* ;
public abstract class MetaInstruction{
    private static Hashtable colorMap ;
    
    static
    {
        colorMap = new Hashtable() ;
        colorMap.put( "black"       , Color.black       ) ;
        colorMap.put( "blue"        , Color.blue        ) ;
        colorMap.put( "cyan"        , Color.cyan        ) ;
        colorMap.put( "darkGray"    , Color.darkGray    ) ;
        colorMap.put( "gray"        , Color.gray        ) ;
        colorMap.put( "green"       , Color.green       ) ;
        colorMap.put( "lightGray"   , Color.lightGray   ) ;
        colorMap.put( "magenta"     , Color.magenta     ) ;
        colorMap.put( "orange"      , Color.orange      ) ;
        colorMap.put( "pink"        , Color.pink        ) ;
        colorMap.put( "red"         , Color.red         ) ;
        colorMap.put( "yellow"      , Color.yellow      ) ;

    }
    
    protected Instruction instruction ;
    
    private MetaInstruction( Instruction instr )
    {
        instruction = instr ;
    }
    
    public abstract void exec( MachineState machineState ) ;

    private static class Annote extends MetaInstruction
    {
        int register ;
        int loDispl, hiDispl ;
        Color color ;
        String text ;
        
        Annote( Instruction i, int r, int l, int h, Color c, String t )
        {
            super( i ) ;
            register = r ;
            loDispl = l ;
            hiDispl = h ;
            color = c ;
            text = t ;
        }
        
        public void exec( MachineState machineState )
        {
            Memory mem = machineState.getMemory() ;
            Registers regs = machineState.getRegisters() ;
            for ( int i = loDispl ; i <= hiDispl ; i++ )
            {
                mem.setAnnotationAt( regs.getRegDispl( register, i ), new MemoryAnnotation( text, color ) ) ;
            }
        }
        
        public String toString()
        {
        	return "Annote reg=" + register + " displ=" + loDispl + "/" + hiDispl + " col=" + color + " text=" + text ;
        }
    }
    
    public static MetaInstruction newAnnote( Instruction instr, Vector args )
    {
        int r = Registers.findRegOfName( (String)args.elementAt(0) ) ;
        int l = Utils.fromHex( (String)args.elementAt(1) ) ;
        int h = Utils.fromHex( (String)args.elementAt(2) ) ;
        Color c = (Color)colorMap.get( (String)args.elementAt(3) ) ;
        String t = (String)args.elementAt(4) ;
        
        if ( r >= 0 && l <= h && c != null && t != null )
            return new Annote( instr, r, l, h, c, t ) ;
        else
            return null ;
    }
    }
\ No newline at end of file
+/**
 * Simple Stack Machine
 *
 * Written by Atze Dijkstra, atze@cs.uu.nl,
 * Copyright Utrecht University.
 *
 */
package nl.uu.cs.ssm ;
import java.util.* ;import java.awt.* ;
public abstract class MetaInstruction{
    private static Hashtable<String,Color> colorMap ;
    
    static
    {
        colorMap = new Hashtable<String,Color>() ;
        colorMap.put( "black"       , Color.black       ) ;
        colorMap.put( "blue"        , Color.blue        ) ;
        colorMap.put( "cyan"        , Color.cyan        ) ;
        colorMap.put( "darkGray"    , Color.darkGray    ) ;
        colorMap.put( "gray"        , Color.gray        ) ;
        colorMap.put( "green"       , Color.green       ) ;
        colorMap.put( "lightGray"   , Color.lightGray   ) ;
        colorMap.put( "magenta"     , Color.magenta     ) ;
        colorMap.put( "orange"      , Color.orange      ) ;
        colorMap.put( "pink"        , Color.pink        ) ;
        colorMap.put( "red"         , Color.red         ) ;
        colorMap.put( "yellow"      , Color.yellow      ) ;

    }
    
    protected Instruction instruction ;
    
    private MetaInstruction( Instruction instr )
    {
        instruction = instr ;
    }
    
    public abstract void exec( MachineState machineState ) ;

    private static class Annote extends MetaInstruction
    {
        int register ;
        int loDispl, hiDispl ;
        Color color ;
        String text ;
        
        Annote( Instruction i, int r, int l, int h, Color c, String t )
        {
            super( i ) ;
            register = r ;
            loDispl = l ;
            hiDispl = h ;
            color = c ;
            text = t ;
        }
        
        public void exec( MachineState machineState )
        {
            Memory mem = machineState.getMemory() ;
            Registers regs = machineState.getRegisters() ;
            for ( int i = loDispl ; i <= hiDispl ; i++ )
            {
                mem.setAnnotationAt( regs.getRegDispl( register, i ), new MemoryAnnotation( text, color ) ) ;
            }
        }
        
        public String toString()
        {
        	return "Annote reg=" + register + " displ=" + loDispl + "/" + hiDispl + " col=" + color + " text=" + text ;
        }
    }
    
    public static MetaInstruction newAnnote( Instruction instr, Vector args )
    {
        int r = Registers.findRegOfName( (String)args.elementAt(0) ) ;
        int l = Utils.fromHex( (String)args.elementAt(1) ) ;
        int h = Utils.fromHex( (String)args.elementAt(2) ) ;
        Color c = (Color)colorMap.get( (String)args.elementAt(3) ) ;
        String t = (String)args.elementAt(4) ;
        
        if ( r >= 0 && l <= h && c != null && t != null )
            return new Annote( instr, r, l, h, c, t ) ;
        else
            return null ;
    }
    }
\ No newline at end of file

src/nl/uu/cs/ssm/Model.java

-/**
 * Simple Stack Machine
 *
 * Written by Atze Dijkstra, atze@cs.uu.nl,
 * Copyright Utrecht University.
 *
 */
package nl.uu.cs.ssm ;
import java.util.* ;
public class Model{
	private Vector listeners = new Vector() ;
	
	protected void addListener( EventListener l )
	{
		listeners.addElement( l ) ;
	}

	protected void removeListener( EventListener l )
	{
		listeners.removeElement( l ) ;
	}
	
	protected Enumeration getListeners()
	{
		return listeners.elements() ;
	}
}
\ No newline at end of file
+/**
 * Simple Stack Machine
 *
 * Written by Atze Dijkstra, atze@cs.uu.nl,
 * Copyright Utrecht University.
 *
 */
package nl.uu.cs.ssm ;
import java.util.* ;
public class Model{
	private Vector<EventListener> listeners = new Vector<EventListener>() ;
	
	protected void addListener( EventListener l )
	{
		listeners.addElement( l ) ;
	}

	protected void removeListener( EventListener l )
	{
		listeners.removeElement( l ) ;
	}
	
	protected Enumeration getListeners()
	{
		return listeners.elements() ;
	}
}
\ No newline at end of file

src/nl/uu/cs/ssm/Registers.java

-/**
 * Simple Stack Machine
 *
 * Written by Atze Dijkstra, atze@cs.uu.nl,
 * Copyright Utrecht University.
 *
 */
package nl.uu.cs.ssm ;
import java.util.* ;
public class Registers extends AbstractMemoryCellModel
	implements MemoryCellModel{
    public static final int     	PC = 0      ;
    public static final int     	SP = 1      ;
    public static final int     	MP = 2      ;
    //public static final int     	RR = 3      ;
    
    private static final int     	nrRegs = 8  ;
    
    private static final String[]	regNames = { "R0", "R1", "R2", "R3", "R4", "R5", "R6", "R7" } ;
    
    private static final String[]	regNamesAlias = { "PC", "SP", "MP", "RR" } ;
    
    //private MemoryCell          	cells[]  	;
    private int          	        cells[]  	;
    
    private Memory					memory		;
    
    private Messenger 				messenger   ;
    
    protected Registers( Memory m, Messenger msgr )
    {
		messenger = msgr ;
    	cells = new int[ nrRegs ] ;
        for ( int i = 0 ; i < cells.length ; i++ )
            //cells[ i ] = new MemoryCell() ;
            cells[ i ] = 0 ;
        memory = m ;
        reset() ;
    }
    
    public void reset()
    {
        for ( int i = 0 ; i < cells.length ; i++ )
            //cells[ i ].setValue( 0 ) ;
            cells[ i ] = 0 ;
    }
    
    public static int getNrRegs( )
    {
        return nrRegs ;
    }
    
    /*
    private static String[] getRegNames( )
    {
        return regNames ;
    }
    */
    
    public static String getRegName( int r )
    {
        return (r < regNames.length && r >= 0) ? regNames[ r ] : ("R"+r) ;
    }
    
    public static String getRegOrAliasName( int r )
    {
    	return r < regNamesAlias.length ? regNamesAlias[r] : getRegName( r ) ;
    }
    
    public static String getRegNAliasName( int r )
    {
        return getRegName(r) + ( r < regNamesAlias.length ? ("(" + regNamesAlias[r] + ")") : "" ) ;
    }
    
    public static Enumeration getRegNAliasNames( )
    {
        Vector v = new Vector() ;
        Utils.addAllTo( v, Utils.asVector( regNames ) ) ;
        Utils.addAllTo( v, Utils.asVector( regNamesAlias ) ) ;
        return v.elements() ;
    }
    
    public static int findRegOfName( String nm ) // should be in some kinda environment
    {
        for ( int i = 0 ; i < regNames.length ; i++ )
        {
            if ( regNames[i].equals( nm ) )
                return i ;
        }
        for ( int i = 0 ; i < regNamesAlias.length ; i++ )
        {
            if ( regNamesAlias[i].equals( nm ) )
                return i ;
        }
        return -1 ;
    }
    
    private boolean checkWithinMemory( int r )
    {
        boolean res ;
        if ( res = ( r < 0 || r >= cells.length ) )
        {
            messenger.println
            	( java.text.MessageFormat.format
            		( "attempt to access nonexisting register {0,number,integer}"
            		, new Object[] { new Integer(r) }
            		) ) ;
        }
        return ! res ;
    }
    
    public int getReg( int r )
    {
        int res = 0 ;
        if ( checkWithinMemory( r ) )
        {
            res = cells[ r ] ;
        }
        return res ;
    }
    
    public int getRegDispl( int r, int d )
    {
        return getReg( r ) + d ;
    }
    
    public int getRegDisplInd( int r, int d )
    {
        return memory.getAt( getRegDispl( r, d ) ) ;
    }
    
    public int getRegInd( int r )
    {
        return getRegDisplInd( r, 0 ) ;
    }
    
    class UndoRegistersModification implements Modification
    {
    	private int offset, value ;
    	
    	UndoRegistersModification( int o, int v )
    	{
    		offset = o ;
    		value = v ;
    	}
    	
    	public void modify()
    	{
    		setReg( offset, value ) ;
    	}
    }
    
    public void setReg( int r, int v )
    {
        if ( checkWithinMemory( r ) )
        {
            int oldv = cells[ r ] ;
            cells[ r ] = v ;
            fireCellChange( this, r, oldv, new UndoRegistersModification( r, oldv ) ) ;
        }
    }
    
    public void setRegDisplInd( int r, int d, int v )
    {
        memory.setAt( getRegDispl( r, d ), v ) ;
    }
    
    public void setRegInd( int r, int v )
    {
        setRegDisplInd( r, 0, v ) ;
    }
    
    public int swapReg( int r, int v )
    {
    	int oldVal = getReg( r ) ;
    	setReg( r, v ) ;
        return oldVal ;
    }
    
    public void adjustReg( int r, int v )
    {
        setReg( r, getReg( r ) + v ) ;
    }
    
    public void setPC( int v )
    {
        setReg( PC, v ) ;
    }
    
    public int getPC( )
    {
        return getReg( PC ) ;
    }
    
    public void adjustPC( int v )
    {
        setPC( getPC() + v ) ;
    }
    
    public void setSP( int v )
    {
        setReg( SP, v ) ;
    }
    
    public int getSP( )
    {
        return getReg( SP ) ;
    }
    
    public void adjustSP( int v )
    {
        setSP( getSP() + v ) ;
    }
    
    public void setMP( int v )
    {
        setReg( MP, v ) ;
    }
    
    public int getMP( )
    {
        return getReg( MP ) ;
    }
    
    public void adjustMP( int v )
    {
        setMP( getMP() + v ) ;
    }
    
    public int getTOS()
    {
        return getRegInd( SP ) ;
    }
    
    public String toString()
    {
    	return "Register PC=" + getReg( PC ) + " SP=" + getReg( SP )  + " MP=" + getReg( MP ) ;
    }
    
}
\ No newline at end of file
+/**
 * Simple Stack Machine
 *
 * Written by Atze Dijkstra, atze@cs.uu.nl,
 * Copyright Utrecht University.
 *
 */
package nl.uu.cs.ssm ;
import java.util.* ;
public class Registers extends AbstractMemoryCellModel
	implements MemoryCellModel{
    public static final int     	PC = 0      ;
    public static final int     	SP = 1      ;
    public static final int     	MP = 2      ;
    //public static final int     	RR = 3      ;
    
    private static final int     	nrRegs = 8  ;
    
    private static final String[]	regNames = { "R0", "R1", "R2", "R3", "R4", "R5", "R6", "R7" } ;
    
    private static final String[]	regNamesAlias = { "PC", "SP", "MP", "RR" } ;
    
    //private MemoryCell          	cells[]  	;
    private int          	        cells[]  	;
    
    private Memory					memory		;
    
    private Messenger 				messenger   ;
    
    protected Registers( Memory m, Messenger msgr )
    {
		messenger = msgr ;
    	cells = new int[ nrRegs ] ;
        for ( int i = 0 ; i < cells.length ; i++ )
            //cells[ i ] = new MemoryCell() ;
            cells[ i ] = 0 ;
        memory = m ;
        reset() ;
    }
    
    public void reset()
    {
        for ( int i = 0 ; i < cells.length ; i++ )
            //cells[ i ].setValue( 0 ) ;
            cells[ i ] = 0 ;
    }
    
    public static int getNrRegs( )
    {
        return nrRegs ;
    }
    
    /*
    private static String[] getRegNames( )
    {
        return regNames ;
    }
    */
    
    public static String getRegName( int r )
    {
        return (r < regNames.length && r >= 0) ? regNames[ r ] : ("R"+r) ;
    }
    
    public static String getRegOrAliasName( int r )
    {
    	return r < regNamesAlias.length ? regNamesAlias[r] : getRegName( r ) ;
    }
    
    public static String getRegNAliasName( int r )
    {
        return getRegName(r) + ( r < regNamesAlias.length ? ("(" + regNamesAlias[r] + ")") : "" ) ;
    }
    
    public static Enumeration<String> getRegNAliasNames( )
    {
        Vector<String> v = new Vector<String>() ;
        Utils.addAllTo( v, Utils.asVector( regNames ) ) ;
        Utils.addAllTo( v, Utils.asVector( regNamesAlias ) ) ;
        return v.elements() ;
    }
    
    public static int findRegOfName( String nm ) // should be in some kinda environment
    {
        for ( int i = 0 ; i < regNames.length ; i++ )
        {
            if ( regNames[i].equals( nm ) )
                return i ;
        }
        for ( int i = 0 ; i < regNamesAlias.length ; i++ )
        {
            if ( regNamesAlias[i].equals( nm ) )
                return i ;
        }
        return -1 ;
    }
    
    private boolean checkWithinMemory( int r )
    {
        boolean res ;
        if ( res = ( r < 0 || r >= cells.length ) )
        {
            messenger.println
            	( java.text.MessageFormat.format
            		( "attempt to access nonexisting register {0,number,integer}"
            		, new Object[] { new Integer(r) }
            		) ) ;
        }
        return ! res ;
    }
    
    public int getReg( int r )
    {
        int res = 0 ;
        if ( checkWithinMemory( r ) )
        {
            res = cells[ r ] ;
        }
        return res ;
    }
    
    public int getRegDispl( int r, int d )
    {
        return getReg( r ) + d ;
    }
    
    public int getRegDisplInd( int r, int d )
    {
        return memory.getAt( getRegDispl( r, d ) ) ;
    }
    
    public int getRegInd( int r )
    {
        return getRegDisplInd( r, 0 ) ;
    }
    
    class UndoRegistersModification implements Modification
    {
    	private int offset, value ;
    	
    	UndoRegistersModification( int o, int v )
    	{
    		offset = o ;
    		value = v ;
    	}
    	
    	public void modify()
    	{
    		setReg( offset, value ) ;
    	}
    }
    
    public void setReg( int r, int v )
    {
        if ( checkWithinMemory( r ) )
        {
            int oldv = cells[ r ] ;
            cells[ r ] = v ;
            fireCellChange( this, r, oldv, new UndoRegistersModification( r, oldv ) ) ;
        }
    }
    
    public void setRegDisplInd( int r, int d, int v )
    {
        memory.setAt( getRegDispl( r, d ), v ) ;
    }
    
    public void setRegInd( int r, int v )
    {
        setRegDisplInd( r, 0, v ) ;
    }
    
    public int swapReg( int r, int v )
    {
    	int oldVal = getReg( r ) ;
    	setReg( r, v ) ;
        return oldVal ;
    }
    
    public void adjustReg( int r, int v )
    {
        setReg( r, getReg( r ) + v ) ;
    }
    
    public void setPC( int v )
    {
        setReg( PC, v ) ;
    }
    
    public int getPC( )
    {
        return getReg( PC ) ;
    }
    
    public void adjustPC( int v )
    {
        setPC( getPC() + v ) ;
    }
    
    public void setSP( int v )
    {
        setReg( SP, v ) ;
    }
    
    public int getSP( )
    {
        return getReg( SP ) ;
    }
    
    public void adjustSP( int v )
    {
        setSP( getSP() + v ) ;
    }
    
    public void setMP( int v )
    {
        setReg( MP, v ) ;
    }
    
    public int getMP( )
    {
        return getReg( MP ) ;
    }
    
    public void adjustMP( int v )
    {
        setMP( getMP() + v ) ;
    }
    
    public int getTOS()
    {
        return getRegInd( SP ) ;
    }
    
    public String toString()
    {
    	return "Register PC=" + getReg( PC ) + " SP=" + getReg( SP )  + " MP=" + getReg( MP ) ;
    }
    
}
\ No newline at end of file

src/nl/uu/cs/ssm/UndoableEvent.java

@@ -12,6 +12,8 @@ import java.util.* ;
 
 public class UndoableEvent extends EventObject
 {
+	private static final long serialVersionUID = 1L ;
+
     private Modification	undoModification	;
     
     protected UndoableEvent( Object src, Modification mdf )
@@ -25,4 +27,4 @@ public class UndoableEvent extends EventObject
         return undoModification ;
     }
     
-}
\ No newline at end of file
+}

src/nl/uu/cs/ssm/Utils.java

-/**
 * Simple Stack Machine
 *
 * Written by Atze Dijkstra, atze@cs.uu.nl,
 * Copyright Utrecht University.
 *
 */
package nl.uu.cs.ssm ;
import java.util.* ;import java.io.* ;import java.awt.* ;import javax.swing.* ;
public class Utils{
    private static final String zeroChars = "00000000" ;
    
    private static final String hexReprPrefix = "0x" ;
    
    public static String asHex( int i, boolean hexIsDefault, boolean signed, boolean padZero )
    {
    	String sign = "" ;
    	if ( signed && i < 0 )
    	{
    		sign = "-" ;
    		i = -i ;
    	}
        String s = Integer.toHexString( i ) ;
        return
        	sign +
        	( hexIsDefault
        	? ( padZero
        	  ? zeroChars.substring( s.length() )
        	  : ""
        	  )
        	: ( i < 10
        	  ? ""
        	  : "0x"
        	  )
        	) + s ;
    }
    
    public static String asHex( int i, boolean hexIsDefault )
    {
        return asHex( i, hexIsDefault, false, true ) ;
    }
    
    public static String asHex( int i )
    {
        return asHex( i, true, false, true ) ;
    }
    
    public static void addAllTo( Vector v, Enumeration es )
    {
    	while( es.hasMoreElements() )
    		v.addElement( es.nextElement() ) ;
    }
    
    public static void addAllTo( Vector v, Vector es )
    {
    	addAllTo( v, es.elements() ) ;
    }
    
    public static Vector asVector( Object[] os )
    {
    	Vector v = new Vector() ;
    	for ( int i = 0 ; i < os.length ; i++ )
    	    v.addElement( os[i] ) ;
    	return v ;
    }
    
    public static Vector splitAt( String s, char sep )
    {
        Vector v = new Vector() ;
        while( true )
        {
            int i = s.indexOf( sep ) ;
            if ( i >= 0 )
            {
                v.addElement( s.substring( 0, i ) ) ;
                s = s.substring( i+1 ) ;
            }
            else
            {
                if ( s.length() > 0 )
                    v.addElement( s ) ;
                break ;
            }
        }
        return v ;
    }
    
    private static int toDigit( char c )
    {
        if (c >= '0' && c <= '9')
            return c - '0' ;
        if (c >= 'a' && c <= 'f')
            return c - 'a' + 10 ;
        if (c >= 'A' && c <= 'F')
            return c - 'A' + 10 ;
        return -1 ;
    }
    
    public static boolean isNumberRepr( String s, boolean hexIsDefault )
    {
        int radix = hexIsDefault ? 16 : 10 ;
        int pos = 0 ;
        if ( s.charAt( 0 ) == '-' )
            pos += 1 ;
        if ( ( ! hexIsDefault ) && s.regionMatches( pos, hexReprPrefix, 0, 2 ) )
            pos += 2 ;
        int max = s.length() ;
        for( ; pos < max ; pos++ )
        {
        	int d = toDigit( s.charAt( pos ) ) ;
            if ( d < 0 || d >= radix )
                return false ;
        }
        return true ;
    }
    
    public static int fromHex( String s, boolean hexIsDefault )
    {
        int radix = hexIsDefault ? 16 : 10 ;
        int res = 0 ;
        int pos = 0 ;
        int sign = 1 ;
        if ( s.charAt( 0 ) == '-' )
        {
            pos += 1 ;
            sign = -1 ;
        }
        if ( ( ! hexIsDefault ) && s.regionMatches( pos, hexReprPrefix, 0, 2 ) )
        {
            pos += 2 ;
            radix = 16 ;
        }
        int max = s.length() ;
        for( ; pos < max ; pos++ )
        {
            int d = toDigit( s.charAt( pos ) ) ;
            //System.out.println( "from hex " + s + " dig " + s.charAt( pos ) + "=" + d ) ;
            if ( ( d < 0 ) || ( radix <= d ) )
                return res ;
            res = res * radix + d ;
        }
        return res * sign ;
    }
    
    public static int fromHex( String s )
    {
        return fromHex( s, true ) ;
    }
    
    public static String repeat( String s, int l )
    {
    	StringBuffer b = new StringBuffer() ;
    	for ( int i = 0 ; i < l ; i++ )
    		b.append( s ) ;
    	return b.toString() ;
    }
    
	public static class ExtensionFileFilter extends javax.swing.filechooser.FileFilter
	{
		private Vector extensions = new Vector() ;
		
		public ExtensionFileFilter( Enumeration exts )
		{
			while ( exts.hasMoreElements() )
				addExtension( (String)exts.nextElement() ) ;
		}
		
		public ExtensionFileFilter( String exts )
		{
			this( new StringTokenizer( exts ) ) ;
		}
		
		public void addExtension( String ext )
		{
			extensions.addElement( ext ) ;
		}
		
		public boolean accept( File f )
		{
			boolean res = true ;
			if ( ! f.isDirectory() )
			{
			    String extension = Utils.getExtension( f ) ;
			    res = (extension != null) && (extensions.contains( extension )) ;
		    }
		    return res ;
		}
		
		public String getDescription()
		{
			return ppList( extensions.elements(), "", ", ", "" ) + " files" ;
		}
	}
	
	/*
     * Get the extension of a file.
     */  
    public static String getExtension( File f )
    {
        String ext = null ;
        String s = f.getName() ;
        int i = s.lastIndexOf( '.' ) ;

        if (i > 0 &&  i < s.length() - 1)
        {
            ext = s.substring( i+1 ).toLowerCase();
        }
        return ext;
    }
    
    public static String ppList( Object l[] )
    {
    	return ppList( Arrays.asList( l ) ) ;
    }
    
    public static String ppList( java.util.List l )
    {
    	return ppList( Collections.enumeration( l ), "[", ",", "]" ) ;
    }
    
    public static String ppList( Enumeration e, String o, String s, String c )
    {
    	StringBuffer b = new StringBuffer() ;
    	b.append( o ) ;
    	if ( e.hasMoreElements() )
    	{
    		b.append( e.nextElement().toString() ) ;
    		while ( e.hasMoreElements() )
    		{
    			b.append( s ) ;
	    		b.append( e.nextElement().toString() ) ;
    		}
    	}
    	b.append( c ) ;
    	return b.toString() ;
    }
    
    public static int indexOf( int a[], int v )
    {
    	for ( int i = 0 ; i < a.length ; i++ )
    		if ( a[i] == v )
    			return v ;
    	return -1 ;
    }

    public static boolean contains( int a[], int v )
    {
    	return indexOf( a, v ) >= 0 ;
    }

	/**
	 * Scroll a component contained in a JScrollPane to its end
	 */
	public static void scrollComponentTo( JComponent c, Rectangle r )
	{
		int extraHeight = 40 ; // 2*r.height ;
		Rectangle rr = new Rectangle( r.x, r.y-extraHeight, r.width, 2*extraHeight+r.height ) ;
		Rectangle rrr = rr.intersection( c.getBounds() ) ;
		//System.out.println( "rr=" + rr + ", rrr=" + rrr + ", bounds=" + c.getBounds() ) ;
		if ( rrr.height > 0 )
			c.scrollRectToVisible( rrr ) ;
	}
	
	/**
	 * Scroll a component contained in a JScrollPane to its end
	 */
	public static void scrollComponentToEnd( JComponent c )
	{
		Rectangle r = c.getBounds() ;
		scrollComponentTo( c, new Rectangle( 0, r.height-2, r.width, 2 ) ) ;
	}
	
}
\ No newline at end of file
+/**
 * Simple Stack Machine
 *
 * Written by Atze Dijkstra, atze@cs.uu.nl,
 * Copyright Utrecht University.
 *
 */
package nl.uu.cs.ssm ;
import java.util.* ;import java.io.* ;import java.awt.* ;import javax.swing.* ;
public class Utils{
    private static final String zeroChars = "00000000" ;
    
    private static final String hexReprPrefix = "0x" ;
    
    public static String asHex( int i, boolean hexIsDefault, boolean signed, boolean padZero )
    {
    	String sign = "" ;
    	if ( signed && i < 0 )
    	{
    		sign = "-" ;
    		i = -i ;
    	}
        String s = Integer.toHexString( i ) ;
        return
        	sign +
        	( hexIsDefault
        	? ( padZero
        	  ? zeroChars.substring( s.length() )
        	  : ""
        	  )
        	: ( i < 10
        	  ? ""
        	  : "0x"
        	  )
        	) + s ;
    }
    
    public static String asHex( int i, boolean hexIsDefault )
    {
        return asHex( i, hexIsDefault, false, true ) ;
    }
    
    public static String asHex( int i )
    {
        return asHex( i, true, false, true ) ;
    }
    
    public static <T> void addAllTo( Vector<T> v, Enumeration<T> es )
    {
    	while( es.hasMoreElements() )
    		v.addElement( es.nextElement() ) ;
    }
    
    public static <T> void addAllTo( Vector<T> v, Vector<T> es )
    {
    	addAllTo( v, es.elements() ) ;
    }
    
    public static <T> Vector<T> asVector( T[] os )
    {
    	Vector<T> v = new Vector<T>() ;
    	for ( int i = 0 ; i < os.length ; i++ )
    	    v.addElement( os[i] ) ;
    	return v ;
    }
    
    public static Vector<String> splitAt( String s, char sep )
    {
        Vector<String> v = new Vector<String>() ;
        while( true )
        {
            int i = s.indexOf( sep ) ;
            if ( i >= 0 )
            {
                v.addElement( s.substring( 0, i ) ) ;
                s = s.substring( i+1 ) ;
            }
            else
            {
                if ( s.length() > 0 )
                    v.addElement( s ) ;
                break ;
            }
        }
        return v ;
    }
    
    private static int toDigit( char c )
    {
        if (c >= '0' && c <= '9')
            return c - '0' ;
        if (c >= 'a' && c <= 'f')
            return c - 'a' + 10 ;
        if (c >= 'A' && c <= 'F')
            return c - 'A' + 10 ;
        return -1 ;
    }
    
    public static boolean isNumberRepr( String s, boolean hexIsDefault )
    {
        int radix = hexIsDefault ? 16 : 10 ;
        int pos = 0 ;
        if ( s.charAt( 0 ) == '-' )
            pos += 1 ;
        if ( ( ! hexIsDefault ) && s.regionMatches( pos, hexReprPrefix, 0, 2 ) )
            pos += 2 ;
        int max = s.length() ;
        for( ; pos < max ; pos++ )
        {
        	int d = toDigit( s.charAt( pos ) ) ;
            if ( d < 0 || d >= radix )
                return false ;
        }
        return true ;
    }
    
    public static int fromHex( String s, boolean hexIsDefault )
    {
        int radix = hexIsDefault ? 16 : 10 ;
        int res = 0 ;
        int pos = 0 ;
        int sign = 1 ;
        if ( s.charAt( 0 ) == '-' )
        {
            pos += 1 ;
            sign = -1 ;
        }
        if ( ( ! hexIsDefault ) && s.regionMatches( pos, hexReprPrefix, 0, 2 ) )
        {
            pos += 2 ;
            radix = 16 ;
        }
        int max = s.length() ;
        for( ; pos < max ; pos++ )
        {
            int d = toDigit( s.charAt( pos ) ) ;
            //System.out.println( "from hex " + s + " dig " + s.charAt( pos ) + "=" + d ) ;
            if ( ( d < 0 ) || ( radix <= d ) )
                return res ;
            res = res * radix + d ;
        }
        return res * sign ;
    }
    
    public static int fromHex( String s )
    {
        return fromHex( s, true ) ;
    }
    
    public static String repeat( String s, int l )
    {
    	StringBuffer b = new StringBuffer() ;
    	for ( int i = 0 ; i < l ; i++ )
    		b.append( s ) ;
    	return b.toString() ;
    }
    
	public static class ExtensionFileFilter extends javax.swing.filechooser.FileFilter
	{
		private Vector<Object> extensions = new Vector<Object>() ;
		
		public ExtensionFileFilter( Enumeration exts )
		{
			while ( exts.hasMoreElements() )
				addExtension( (String)exts.nextElement() ) ;
		}
		
		public ExtensionFileFilter( String exts )
		{
			this( new StringTokenizer( exts ) ) ;
		}
		
		public void addExtension( String ext )
		{
			extensions.addElement( ext ) ;
		}
		
		public boolean accept( File f )
		{
			boolean res = true ;
			if ( ! f.isDirectory() )
			{
			    String extension = Utils.getExtension( f ) ;
			    res = (extension != null) && (extensions.contains( extension )) ;
		    }
		    return res ;
		}
		
		public String getDescription()
		{
			return ppList( extensions.elements(), "", ", ", "" ) + " files" ;
		}
	}
	
	/*
     * Get the extension of a file.
     */  
    public static String getExtension( File f )
    {
        String ext = null ;
        String s = f.getName() ;
        int i = s.lastIndexOf( '.' ) ;

        if (i > 0 &&  i < s.length() - 1)
        {
            ext = s.substring( i+1 ).toLowerCase();
        }
        return ext;
    }
    
    public static String ppList( Object l[] )
    {
    	return ppList( Arrays.asList( l ) ) ;
    }
    
    public static String ppList( java.util.List<Object> l )
    {
    	return ppList( Collections.enumeration( l ), "[", ",", "]" ) ;
    }
    
    public static String ppList( Enumeration<Object> e, String o, String s, String c )
    {
    	StringBuffer b = new StringBuffer() ;
    	b.append( o ) ;
    	if ( e.hasMoreElements() )
    	{
    		b.append( e.nextElement().toString() ) ;
    		while ( e.hasMoreElements() )
    		{
    			b.append( s ) ;
	    		b.append( e.nextElement().toString() ) ;
    		}
    	}
    	b.append( c ) ;
    	return b.toString() ;
    }
    
    public static int indexOf( int a[], int v )
    {
    	for ( int i = 0 ; i < a.length ; i++ )
    		if ( a[i] == v )
    			return v ;
    	return -1 ;
    }

    public static boolean contains( int a[], int v )
    {
    	return indexOf( a, v ) >= 0 ;
    }

	/**
	 * Scroll a component contained in a JScrollPane to its end
	 */
	public static void scrollComponentTo( JComponent c, Rectangle r )
	{
		int extraHeight = 40 ; // 2*r.height ;
		Rectangle rr = new Rectangle( r.x, r.y-extraHeight, r.width, 2*extraHeight+r.height ) ;
		Rectangle rrr = rr.intersection( c.getBounds() ) ;
		//System.out.println( "rr=" + rr + ", rrr=" + rrr + ", bounds=" + c.getBounds() ) ;
		if ( rrr.height > 0 )
			c.scrollRectToVisible( rrr ) ;
	}
	
	/**
	 * Scroll a component contained in a JScrollPane to its end
	 */
	public static void scrollComponentToEnd( JComponent c )
	{
		Rectangle r = c.getBounds() ;
		scrollComponentTo( c, new Rectangle( 0, r.height-2, r.width, 2 ) ) ;
	}
	
}
\ No newline at end of file

src/nl/uu/cs/ssmui/AssemblyParseResult.java

-/* 
	Runner.java

	Title:			Simple Stack Machine Runner
	Author:			atze
	Description:	
*/
package nl.uu.cs.ssmui;
import javax.swing.*;
import java.util.* ;
import nl.uu.cs.ssm.* ;
class AssemblyParseResult {
    protected int lineNr ;
    protected String message ;
    protected Vector definedLabels ;
    protected Vector instrNArgs ;
    
    protected AssemblyParseResult( int l, String m, String lb, Vector ia )
    {
        definedLabels = new Vector() ;
        addInfo( l, m, lb, ia ) ;
    }
    
    protected AssemblyParseResult addInfo( int l, String m, String lb, Vector ia )
    {
        lineNr = l ;
        message = m ;
        if ( lb != null )
            definedLabels.addElement( lb ) ;
        instrNArgs = ia ;
        return this ;
    }
    
    public String toString()
    {
        return "line " + lineNr + "(" + message + "), " + definedLabels + ": " + instrNArgs ;
    }
    
    public void addLabels( Vector ls )
    {
        Utils.addAllTo( definedLabels, ls.elements() ) ;
    }
    }
\ No newline at end of file
+/* 
	Runner.java

	Title:			Simple Stack Machine Runner
	Author:			atze
	Description:	
*/
package nl.uu.cs.ssmui;
import javax.swing.*;
import java.util.* ;
import nl.uu.cs.ssm.* ;
class AssemblyParseResult {
    protected int lineNr ;
    protected String message ;
    protected Vector<String> definedLabels ;
    protected Vector<String> instrNArgs ;
    
    protected AssemblyParseResult( int l, String m, String lb, Vector<String> ia )
    {
        definedLabels = new Vector<String>() ;
        addInfo( l, m, lb, ia ) ;
    }
    
    protected AssemblyParseResult addInfo( int l, String m, String lb, Vector<String> ia )
    {
        lineNr = l ;
        message = m ;
        if ( lb != null )
            definedLabels.addElement( lb ) ;
        instrNArgs = ia ;
        return this ;
    }
    
    public String toString()
    {
        return "line " + lineNr + "(" + message + "), " + definedLabels + ": " + instrNArgs ;
    }
    
    public void addLabels( Vector<String> ls )
    {
        Utils.addAllTo( definedLabels, ls.elements() ) ;
    }
    }
\ No newline at end of file

src/nl/uu/cs/ssmui/AssemblyParser.java

-/* 
	Runner.java

	Title:			Simple Stack Machine Runner
	Author:			atze
	Description:	
*/
package nl.uu.cs.ssmui;
import javax.swing.*;
import java.io.* ;import java.util.* ;
public class AssemblyParser {
    private StreamTokenizer tokens ;
    private int tok ;
    
    protected AssemblyParser( Reader input )
    {
        tokens = new StreamTokenizer( input ) ;
        tokens.resetSyntax() ;
        tokens.wordChars( '0', '9' ) ;
        tokens.wordChars( 'a', 'z' ) ;
        tokens.wordChars( 'A', 'Z' ) ;
        tokens.wordChars( 0xA0, 0xF0 ) ;
        tokens.wordChars( '_', '_' ) ;
        tokens.wordChars( '-', '-' ) ;
        tokens.whitespaceChars( 0x00, 0x20 ) ;
        tokens.commentChar( ';' ) ;
        tokens.quoteChar( '"' ) ;
        tokens.eolIsSignificant( true ) ;
        tokens.slashSlashComments( true ) ;
        next() ;
    }
    
    private void next()
    {
        try
        {
            if ( ! isAtEOF() )
                tok = tokens.nextToken() ;
        }
        catch ( IOException ex )
        {
            tok = tokens.TT_EOF ;
        }
    }
    
    public boolean isAtEOF()
    {
        return tok == tokens.TT_EOF ;
    }
    
    private boolean isAtEOL()
    {
        return tok == tokens.TT_EOL || isAtEOF() ;
    }
    
    protected AssemblyParseResult parse1Line( AssemblyParseResult prevAPR )
    {
        int lineNr = tokens.lineno() ;
        String label = null ;
        String msg = null ;
        Vector instrNArgs = new Vector() ;
        
        if ( ! isAtEOL() )
        {
            if ( tok == tokens.TT_WORD )
            {
                String s = tokens.sval ;
                next() ;
                if ( tok == ':' )
                {
                    label = s ;
                    next() ;
                }
                else
                {
                    instrNArgs.addElement( s ) ;
                }
                
                while( ! isAtEOL() )
                {
                    if ( tok == tokens.TT_WORD || tok == '"' )
                    {
                        instrNArgs.addElement( tokens.sval ) ;
                    }
                    else if ( tok == tokens.TT_NUMBER )
                    {
                        msg = "did not expect number " + tokens.nval ;
                    }
                    else
                    {
                        msg = "did not expect `" + (char)tok + "'" ;
                    }
                    next() ;
                }
            }
            else
            {
                msg = "expected label or instruction" ;
            }
        }
        next() ;

        if ( prevAPR == null )
            return new AssemblyParseResult( lineNr, msg, label, instrNArgs ) ;
        else
            return prevAPR.addInfo( lineNr, msg, label, instrNArgs ) ;
    }
    }
\ No newline at end of file
+/* 
	Runner.java

	Title:			Simple Stack Machine Runner
	Author:			atze
	Description:	
*/
package nl.uu.cs.ssmui;
import javax.swing.*;
import java.io.* ;import java.util.* ;
public class AssemblyParser {
    private StreamTokenizer tokens ;
    private int tok ;
    
    protected AssemblyParser( Reader input )
    {
        tokens = new StreamTokenizer( input ) ;
        tokens.resetSyntax() ;
        tokens.wordChars( '0', '9' ) ;
        tokens.wordChars( 'a', 'z' ) ;
        tokens.wordChars( 'A', 'Z' ) ;
        tokens.wordChars( 0xA0, 0xF0 ) ;
        tokens.wordChars( '_', '_' ) ;
        tokens.wordChars( '-', '-' ) ;
        tokens.whitespaceChars( 0x00, 0x20 ) ;
        tokens.commentChar( ';' ) ;
        tokens.quoteChar( '"' ) ;
        tokens.eolIsSignificant( true ) ;
        tokens.slashSlashComments( true ) ;
        next() ;
    }
    
    private void next()
    {
        try
        {
            if ( ! isAtEOF() )
                tok = tokens.nextToken() ;
        }
        catch ( IOException ex )
        {
            tok = tokens.TT_EOF ;
        }
    }
    
    public boolean isAtEOF()
    {
        return tok == tokens.TT_EOF ;
    }
    
    private boolean isAtEOL()
    {
        return tok == tokens.TT_EOL || isAtEOF() ;
    }
    
    protected AssemblyParseResult parse1Line( AssemblyParseResult prevAPR )
    {
        int lineNr = tokens.lineno() ;
        String label = null ;
        String msg = null ;
        Vector<String> instrNArgs = new Vector<String>() ;
        
        if ( ! isAtEOL() )
        {
            if ( tok == tokens.TT_WORD )
            {
                String s = tokens.sval ;
                next() ;
                if ( tok == ':' )
                {
                    label = s ;
                    next() ;
                }
                else
                {
                    instrNArgs.addElement( s ) ;
                }
                
                while( ! isAtEOL() )
                {
                    if ( tok == tokens.TT_WORD || tok == '"' )
                    {
                        instrNArgs.addElement( tokens.sval ) ;
                    }
                    else if ( tok == tokens.TT_NUMBER )
                    {
                        msg = "did not expect number " + tokens.nval ;
                    }
                    else
                    {
                        msg = "did not expect `" + (char)tok + "'" ;
                    }
                    next() ;
                }
            }
            else
            {
                msg = "expected label or instruction" ;
            }
        }
        next() ;

        if ( prevAPR == null )
            return new AssemblyParseResult( lineNr, msg, label, instrNArgs ) ;
        else
            return prevAPR.addInfo( lineNr, msg, label, instrNArgs ) ;
    }
    }
\ No newline at end of file

src/nl/uu/cs/ssmui/Help.java

-/* 
	Help.java

	Title:			Simple Stack Machine Runner
	Author:			atze
	Description:	
*/
package nl.uu.cs.ssmui;
//import javax.swing.*;
import java.util.* ;

import nl.uu.cs.ssm.* ;

public class Help 
{
	private Vector helpSuppliers ;
	
	public Help()
	{
		helpSuppliers = new Vector() ;
	}
	
	public void addHelpSupplier( HelpSupplier hs )
	{
		helpSuppliers.addElement( hs ) ;
	}
	
	private static void addSorted( Vector v, HelpTopic ht )
	{
	    int max = v.size() ;
	    int i ;
	    for ( i = 0 ; i < max ; i++ )
	    {
	        if ( ht.toString().toLowerCase().compareTo( v.elementAt(i).toString().toLowerCase() ) < 0 )
	            break ;
	    }
	    if ( i >= max )
	        v.addElement( ht ) ;
	    else
	        v.insertElementAt( ht, i ) ;
	}
	
	public Vector findTopics( String key )
	{
		Vector topics = new Vector() ;
		if ( key != null )
    		key = key.toLowerCase() ;
		
		for ( Enumeration hss = helpSuppliers.elements() ; hss.hasMoreElements() ; )
		{
			HelpSupplier hs = (HelpSupplier)hss.nextElement() ;
			for ( Enumeration ts = hs.getTopics() ; ts.hasMoreElements() ; )
			{
				String t = (String)ts.nextElement() ;
				if ( key == null || t.toLowerCase().indexOf( key ) >= 0 )
    				addSorted( topics, new HelpTopic( hs, t ) ) ;
			}
		}
		
		return topics ;
	}
	
	
}
\ No newline at end of file
+/* 
	Help.java

	Title:			Simple Stack Machine Runner
	Author:			atze
	Description:	
*/
package nl.uu.cs.ssmui;
//import javax.swing.*;
import java.util.* ;

import nl.uu.cs.ssm.* ;

public class Help 
{
	private Vector<HelpSupplier> helpSuppliers ;
	
	public Help()
	{
		helpSuppliers = new Vector<HelpSupplier>() ;
	}
	
	public void addHelpSupplier( HelpSupplier hs )
	{
		helpSuppliers.addElement( hs ) ;
	}
	
	private static void addSorted( Vector<HelpTopic> v, HelpTopic ht )
	{
	    int max = v.size() ;
	    int i ;
	    for ( i = 0 ; i < max ; i++ )
	    {
	        if ( ht.toString().toLowerCase().compareTo( v.elementAt(i).toString().toLowerCase() ) < 0 )
	            break ;
	    }
	    if ( i >= max )
	        v.addElement( ht ) ;
	    else
	        v.insertElementAt( ht, i ) ;
	}
	
	public Vector<HelpTopic> findTopics( String key )
	{
		Vector<HelpTopic> topics = new Vector<HelpTopic>() ;
		if ( key != null )
    		key = key.toLowerCase() ;
		
		for ( Enumeration<HelpSupplier> hss = helpSuppliers.elements() ; hss.hasMoreElements() ; )
		{
			HelpSupplier hs = (HelpSupplier)hss.nextElement() ;
			for ( Enumeration<String> ts = hs.getTopics() ; ts.hasMoreElements() ; )
			{
				String t = (String)ts.nextElement() ;
				if ( key == null || t.toLowerCase().indexOf( key ) >= 0 )
    				addSorted( topics, new HelpTopic( hs, t ) ) ;
			}
		}
		
		return topics ;
	}
	
	
}
\ No newline at end of file

src/nl/uu/cs/ssmui/HelpFromProp.java

-/* 
	Runner.java

	Title:			Simple Stack Machine Runner
	Author:			atze
	Description:	
*/
package nl.uu.cs.ssmui;
import nl.uu.cs.ssm.* ;
import java.net.* ;import java.util.* ;import java.io.* ;
public class HelpFromProp
	implements HelpSupplier{
	private static final char 		US 				= '_' 			;
	private static final char 		SEP 			= ',' 			;
	private static final char 		INDIRECT		= '@' 			;
	
	private static final String 	PROP_DESCR 		= "descr" 		;
	private static final String 	PROP_PREPOST 	= "prepost" 	;
	private static final String 	PROP_EXAMPLE 	= "example" 	;
	
	private boolean                 doForInstr                       ;
	
	private static Properties getProps( String nm )
	{
		URL url = nm.getClass().getResource( "/Help/" + nm + ".prop" ) ;
		Properties props = new Properties() ;
		try
		{
			props.load( url.openStream() ) ;
		}
		catch( IOException ex )
		{
		}
		return props ;
	}
	
	private Properties props ;
	private Vector topics = null ;
	private HelpSupplier instrHelpSupplier ;
	
	protected HelpFromProp( String propnm, HelpSupplier ih, boolean doForInstr )
	{
		this.doForInstr = doForInstr ;
		props = getProps( propnm ) ;
		instrHelpSupplier = ih ;
	}

	private void checkTopics()
	{
		if ( topics == null )
		{
			Hashtable ts = new Hashtable() ;
			for ( Enumeration ps = props.propertyNames() ; ps.hasMoreElements() ; )
			{
				String s = (String)ps.nextElement() ;
				if ( doForInstr )
				{
    				int i = s.indexOf( US ) ;
    				if ( i > 0 )
    					s = s.substring( 0, i ) ;
				}
				ts.put( s, s ) ;
			}
			topics = new Vector( ) ;
			Utils.addAllTo( topics, ts.elements() ) ;
		}
	}
	
    public Enumeration getTopics()
    {
    	checkTopics() ;
    	return topics.elements() ;
    }
    
    public String getHelpSupplierName()
    {
    	return doForInstr ? "Semantics" : "General" ;
    }
    
    public String getShortSummaryForTopic( String topic )
    {
        return topic + " " + getHelpSupplierName().toLowerCase() ;
    }
    
    private String getTopicProperty( String topicProp )
    {
    	String p = props.getProperty( topicProp ) ;
    	if ( p != null && p.length() > 0 && p.charAt(0) == INDIRECT )
    	{
    		p = getTopicProperty( p.substring(1) ) ;
    	}
    	if ( p == null )
    	    p = "No info" ;
    	return p ;
    }
    
    private String getTopicProperty( String topic, String prop )
    {
    	return getTopicProperty( topic + US + prop ) ;
    }
    
    /*
    private void commasep( String s, HelpAccumulator acc )
    {
        Vector v = Utils.splitAt( s, SEP ) ;
        if ( v.size() < 1 )
            return ;
            
        int max = v.size() - 1 ;
        for ( int i = 0  ; i < max ; i++ )
        {
            acc.append( ((String)v.elementAt(i)).trim() ) ;
            acc.linebreak() ;
        }
        acc.append( ((String)v.elementAt( max )).trim() ) ;
    }
    */
    
    private Enumeration splitByComma( String s )
    {
        Vector v = Utils.splitAt( s, SEP ) ;
        Vector vv = new Vector() ;
        for ( Enumeration e = v.elements() ; e.hasMoreElements() ; )
        	vv.addElement( ((String)e.nextElement()).trim() ) ;
        return vv.elements() ;
    }
    
    public void getHelpForTopic( String topic, HelpAccumulator acc )
    {
        Vector v ;
        Enumeration e ;
        
        if ( doForInstr )
        {
            instrHelpSupplier.getHelpForTopic( topic, acc ) ;
            acc.linebreak() ;
            
            acc.beginAttributeList() ;
            acc.attributeName( "Description" ) ;
            acc.beginAttributeValue() ;
            acc.append( getTopicProperty( topic, PROP_DESCR ) ) ;
            acc.endAttributeValue() ;

            acc.attributeName( "Pre and Post State" ) ;
            acc.beginAttributeValue() ;
            e = splitByComma( getTopicProperty( topic, PROP_PREPOST) ) ;
            acc.mathEquationList( e, US ) ;
            acc.endAttributeValue() ;

            acc.attributeName( "Example" ) ;
            acc.beginAttributeValue() ;
            e = splitByComma( getTopicProperty( topic, PROP_EXAMPLE) ) ;
            acc.verbatimList( e ) ;
            acc.endAttributeValue() ;
            acc.endAttributeList() ;
        }
        else
        {
            acc.beginBlockQuote() ;
            acc.append( getTopicProperty( topic ) ) ;
            acc.endBlockQuote() ;
        }
    }
    }
\ No newline at end of file
+/* 
	Runner.java

	Title:			Simple Stack Machine Runner
	Author:			atze
	Description:	
*/
package nl.uu.cs.ssmui;
import nl.uu.cs.ssm.* ;
import java.net.* ;import java.util.* ;import java.io.* ;
public class HelpFromProp
	implements HelpSupplier{
	private static final char 		US 				= '_' 			;
	private static final char 		SEP 			= ',' 			;
	private static final char 		INDIRECT		= '@' 			;
	
	private static final String 	PROP_DESCR 		= "descr" 		;
	private static final String 	PROP_PREPOST 	= "prepost" 	;
	private static final String 	PROP_EXAMPLE 	= "example" 	;
	
	private boolean                 doForInstr                       ;
	
	private static Properties getProps( String nm )
	{
		URL url = nm.getClass().getResource( "/Help/" + nm + ".prop" ) ;
		Properties props = new Properties() ;
		try
		{
			props.load( url.openStream() ) ;
		}
		catch( IOException ex )
		{
		}
		return props ;
	}
	
	private Properties props ;
	private Vector<String> topics = null ;
	private HelpSupplier instrHelpSupplier ;
	
	protected HelpFromProp( String propnm, HelpSupplier ih, boolean doForInstr )
	{
		this.doForInstr = doForInstr ;
		props = getProps( propnm ) ;
		instrHelpSupplier = ih ;
	}

	private void checkTopics()
	{
		if ( topics == null )
		{
			Hashtable<String,String> ts = new Hashtable<String,String>() ;
			for ( Enumeration ps = props.propertyNames() ; ps.hasMoreElements() ; )
			{
				String s = (String)ps.nextElement() ;
				if ( doForInstr )
				{
    				int i = s.indexOf( US ) ;
    				if ( i > 0 )
    					s = s.substring( 0, i ) ;
				}
				ts.put( s, s ) ;
			}
			topics = new Vector<String>( ) ;
			Utils.addAllTo( topics, ts.elements() ) ;
		}
	}
	
    public Enumeration<String> getTopics()
    {
    	checkTopics() ;
    	return topics.elements() ;
    }
    
    public String getHelpSupplierName()
    {
    	return doForInstr ? "Semantics" : "General" ;
    }
    
    public String getShortSummaryForTopic( String topic )
    {
        return topic + " " + getHelpSupplierName().toLowerCase() ;
    }
    
    private String getTopicProperty( String topicProp )
    {
    	String p = props.getProperty( topicProp ) ;
    	if ( p != null && p.length() > 0 && p.charAt(0) == INDIRECT )
    	{
    		p = getTopicProperty( p.substring(1) ) ;
    	}
    	if ( p == null )
    	    p = "No info" ;
    	return p ;
    }
    
    private String getTopicProperty( String topic, String prop )
    {
    	return getTopicProperty( topic + US + prop ) ;
    }
    
    /*
    private void commasep( String s, HelpAccumulator acc )
    {
        Vector v = Utils.splitAt( s, SEP ) ;
        if ( v.size() < 1 )
            return ;
            
        int max = v.size() - 1 ;
        for ( int i = 0  ; i < max ; i++ )
        {
            acc.append( ((String)v.elementAt(i)).trim() ) ;
            acc.linebreak() ;
        }
        acc.append( ((String)v.elementAt( max )).trim() ) ;
    }
    */
    
    private Enumeration<String> splitByComma( String s )
    {
        Vector<String> v = Utils.splitAt( s, SEP ) ;
        Vector<String> vv = new Vector<String>() ;
        for ( Enumeration<String> e = v.elements() ; e.hasMoreElements() ; )
        	vv.addElement( ((String)e.nextElement()).trim() ) ;
        return vv.elements() ;
    }
    
    public void getHelpForTopic( String topic, HelpAccumulator acc )
    {
        Vector v ;
        Enumeration e ;
        
        if ( doForInstr )
        {
            instrHelpSupplier.getHelpForTopic( topic, acc ) ;
            acc.linebreak() ;
            
            acc.beginAttributeList() ;
            acc.attributeName( "Description" ) ;
            acc.beginAttributeValue() ;
            acc.append( getTopicProperty( topic, PROP_DESCR ) ) ;
            acc.endAttributeValue() ;

            acc.attributeName( "Pre and Post State" ) ;
            acc.beginAttributeValue() ;
            e = splitByComma( getTopicProperty( topic, PROP_PREPOST) ) ;
            acc.mathEquationList( e, US ) ;
            acc.endAttributeValue() ;

            acc.attributeName( "Example" ) ;
            acc.beginAttributeValue() ;
            e = splitByComma( getTopicProperty( topic, PROP_EXAMPLE) ) ;
            acc.verbatimList( e ) ;
            acc.endAttributeValue() ;
            acc.endAttributeList() ;
        }
        else
        {
            acc.beginBlockQuote() ;
            acc.append( getTopicProperty( topic ) ) ;
            acc.endBlockQuote() ;
        }
    }
    }
\ No newline at end of file

src/nl/uu/cs/ssmui/Labels.java

-/* 
	Title:			Simple Stack Machine Runner
	Author:			atze
	Description:	
*/
package nl.uu.cs.ssmui;
import java.util.*;
class Labels{
    public static final int UNDEFINED = Integer.MAX_VALUE ;
    
    private class Label
    {
        String      label ;
        boolean     isAbsolute ;
        boolean     isWhatItIs ;
        boolean     isResolved ;
        int         row ;
        
        Label( String nm, int r, boolean reslv )
        {
            label = nm ;
            row = r ;
            isAbsolute = false ;
            isResolved = reslv ;
            isWhatItIs = false ;
        }
    }
    
    private class UnresolvedLabelUsage
    {
        Label       label ;
        int         row ;
        int         insideInstOffset ;
        int         pcOffset ;
        boolean     isRelative ;
        
        UnresolvedLabelUsage( Label l, int r, int offs, int pcoffs, boolean isRel )
        {
            label = l ;
            row = r ;
            insideInstOffset = offs ;
            pcOffset = pcoffs ;
            isRelative = isRel ;
        }
        
        public String toString()
        {
            return label.label ;
        }
    }
    
    private Hashtable       labels              ;
    private Vector          unresolvedUsages    ;
    
    private CodeRowSupplier codeSupplier        ;
    
    protected Labels( CodeRowSupplier cs )
    {
        codeSupplier = cs ;
        reset(null) ;
    }
    
    protected void reset( Enumeration regNames )
    {
        if ( regNames != null )
        {
            labels = new Hashtable() ;
            for ( ; regNames.hasMoreElements() ; )
            {
                String nm = (String)regNames.nextElement() ;
                defineRegName( nm, nl.uu.cs.ssm.Registers.findRegOfName( nm ) ) ; // not neat, ??? TBD
            }
        }
        unresolvedUsages = new Vector() ;
    }
    
    protected void shiftAt( int row, int v )
    {
    }
    
    private Label findLabelByName( String nm )
    {
        Label res = (Label)labels.get( nm ) ;
        return res ;
    }
    
    protected String findLabelNameAtRow( int row )
    {
        for ( Enumeration e = labels.elements() ; e.hasMoreElements() ; )
        {
            Label l = (Label)e.nextElement() ;
            if ( l.row == row )
                return l.label ;
        }
        return "" ;
    }
    
    protected boolean labelIsDefined( String nm )
    {
        return findLabelByName( nm ) != null ;
    }
    
    private void defineRegName( String nm, int val )
    {
        Label l = new Label( nm, val, true ) ;
        l.isAbsolute = l.isWhatItIs = true ;
        labels.put( nm, l ) ;
    }
    
    private Label defineLabel( String nm, int row, boolean resolved )
    {
        Label l ;
        if ( ( l = findLabelByName( nm ) ) != null )
        {
            if ( ! l.isResolved )
            {
                l.isResolved = true ;
                l.row = row ;
            }
        }
        else
        {
            l = new Label( nm, row, resolved ) ;
            labels.put( nm, l ) ;
        }
        //System.out.println( "defined label " + nm + " row=" + row + " loc=" + codeSupplier.memLocOfRow(row) ) ;
        return l ;
    }
    
    protected void defineLabel( String nm, int row )
    {
        defineLabel( nm, row, true ) ;
    }
    
    protected int useLabel( String nm, int row, int offset, int pcOffset, boolean isRelative )
    {
        return useLabel( nm, row, offset, pcOffset, true, isRelative) ;
    }
    
    private int useLabel( String nm, int row, int offset, int pcOffset, boolean doAddUnresolved, boolean isRelative )
    {
        int res ;
        Label l = findLabelByName( nm ) ;
        if ( l != null && l.isResolved )
        {
            if ( l.isWhatItIs )
            {
                res = l.row ;
            }
            else
            {
                int labelLoc = codeSupplier.memLocOfRow( l.row ) ;
                int useLoc = codeSupplier.memLocOfRow( row ) + pcOffset ;
                res = ( (l.isAbsolute || (! isRelative)) ? labelLoc : labelLoc - useLoc ) ;
                //System.out.println( "use label " + nm + " res=" + res + " useloc=" + useLoc ) ;
            }
        }
        else
        {
            if ( l == null )
            {
                l = defineLabel( nm, 0, false ) ;
            }
            if ( doAddUnresolved )
                unresolvedUsages.addElement( new UnresolvedLabelUsage( l, row, offset, pcOffset, isRelative ) ) ;
            res = UNDEFINED ;
        }
        return res ;
    }
    
    protected Vector resolveUnresolved()
    {
        Vector stillUnresolved = new Vector() ;
        
        for ( Enumeration ls = unresolvedUsages.elements() ; ls.hasMoreElements() ; )
        {
            UnresolvedLabelUsage ul = (UnresolvedLabelUsage)ls.nextElement() ;
            int val = useLabel( ul.label.label, ul.row, ul.insideInstOffset, ul.pcOffset, false, ul.isRelative ) ;
            if ( val == UNDEFINED )
                stillUnresolved.addElement( ul ) ;
            else
                codeSupplier.setInstrArgAt( ul.row, ul.insideInstOffset, val ) ;
        }
        
        return stillUnresolved ;
    }
    
}
\ No newline at end of file
+/* 
	Title:			Simple Stack Machine Runner
	Author:			atze
	Description:	
*/
package nl.uu.cs.ssmui;
import java.util.*;
class Labels{
    public static final int UNDEFINED = Integer.MAX_VALUE ;
    
    private class Label
    {
        String      label ;
        boolean     isAbsolute ;
        boolean     isWhatItIs ;
        boolean     isResolved ;
        int         row ;
        
        Label( String nm, int r, boolean reslv )
        {
            label = nm ;
            row = r ;
            isAbsolute = false ;
            isResolved = reslv ;
            isWhatItIs = false ;
        }
    }
    
    private class UnresolvedLabelUsage
    {
        Label       label ;
        int         row ;
        int         insideInstOffset ;
        int         pcOffset ;
        boolean     isRelative ;
        
        UnresolvedLabelUsage( Label l, int r, int offs, int pcoffs, boolean isRel )
        {
            label = l ;
            row = r ;
            insideInstOffset = offs ;
            pcOffset = pcoffs ;
            isRelative = isRel ;
        }
        
        public String toString()
        {
            return label.label ;
        }
    }
    
    private Hashtable<String,Label>       labels              ;
    private Vector<UnresolvedLabelUsage>          unresolvedUsages    ;
    
    private CodeRowSupplier codeSupplier        ;
    
    protected Labels( CodeRowSupplier cs )
    {
        codeSupplier = cs ;
        reset(null) ;
    }
    
    protected void reset( Enumeration regNames )
    {
        if ( regNames != null )
        {
            labels = new Hashtable<String,Label>() ;
            for ( ; regNames.hasMoreElements() ; )
            {
                String nm = (String)regNames.nextElement() ;
                defineRegName( nm, nl.uu.cs.ssm.Registers.findRegOfName( nm ) ) ; // not neat, ??? TBD
            }
        }
        unresolvedUsages = new Vector<UnresolvedLabelUsage>() ;
    }
    
    protected void shiftAt( int row, int v )
    {
    }
    
    private Label findLabelByName( String nm )
    {
        Label res = (Label)labels.get( nm ) ;
        return res ;
    }
    
    protected String findLabelNameAtRow( int row )
    {
        for ( Enumeration<Label> e = labels.elements() ; e.hasMoreElements() ; )
        {
            Label l = (Label)e.nextElement() ;
            if ( l.row == row )
                return l.label ;
        }
        return "" ;
    }
    
    protected boolean labelIsDefined( String nm )
    {
        return findLabelByName( nm ) != null ;
    }
    
    private void defineRegName( String nm, int val )
    {
        Label l = new Label( nm, val, true ) ;
        l.isAbsolute = l.isWhatItIs = true ;
        labels.put( nm, l ) ;
    }
    
    private Label defineLabel( String nm, int row, boolean resolved )
    {
        Label l ;
        if ( ( l = findLabelByName( nm ) ) != null )
        {
            if ( ! l.isResolved )
            {
                l.isResolved = true ;
                l.row = row ;
            }
        }
        else
        {
            l = new Label( nm, row, resolved ) ;
            labels.put( nm, l ) ;
        }
        //System.out.println( "defined label " + nm + " row=" + row + " loc=" + codeSupplier.memLocOfRow(row) ) ;
        return l ;
    }
    
    protected void defineLabel( String nm, int row )
    {
        defineLabel( nm, row, true ) ;
    }
    
    protected int useLabel( String nm, int row, int offset, int pcOffset, boolean isRelative )
    {
        return useLabel( nm, row, offset, pcOffset, true, isRelative) ;
    }
    
    private int useLabel( String nm, int row, int offset, int pcOffset, boolean doAddUnresolved, boolean isRelative )
    {
        int res ;
        Label l = findLabelByName( nm ) ;
        if ( l != null && l.isResolved )
        {
            if ( l.isWhatItIs )
            {
                res = l.row ;
            }
            else
            {
                int labelLoc = codeSupplier.memLocOfRow( l.row ) ;
                int useLoc = codeSupplier.memLocOfRow( row ) + pcOffset ;
                res = ( (l.isAbsolute || (! isRelative)) ? labelLoc : labelLoc - useLoc ) ;
                //System.out.println( "use label " + nm + " res=" + res + " useloc=" + useLoc ) ;
            }
        }
        else
        {
            if ( l == null )
            {
                l = defineLabel( nm, 0, false ) ;
            }
            if ( doAddUnresolved )
                unresolvedUsages.addElement( new UnresolvedLabelUsage( l, row, offset, pcOffset, isRelative ) ) ;
            res = UNDEFINED ;
        }
        return res ;
    }
    
    protected Vector resolveUnresolved()
    {
        Vector<UnresolvedLabelUsage> stillUnresolved = new Vector<UnresolvedLabelUsage>() ;
        
        for ( Enumeration<UnresolvedLabelUsage> ls = unresolvedUsages.elements() ; ls.hasMoreElements() ; )
        {
            UnresolvedLabelUsage ul = (UnresolvedLabelUsage)ls.nextElement() ;
            int val = useLabel( ul.label.label, ul.row, ul.insideInstOffset, ul.pcOffset, false, ul.isRelative ) ;
            if ( val == UNDEFINED )
                stillUnresolved.addElement( ul ) ;
            else
                codeSupplier.setInstrArgAt( ul.row, ul.insideInstOffset, val ) ;
        }
        
        return stillUnresolved ;
    }
    
}
\ No newline at end of file

src/nl/uu/cs/ssmui/SSMAbout.java

-package nl.uu.cs.ssmui;
import java.awt.*;import java.awt.event.*;import javax.swing.*;
import nl.uu.cs.ssm.* ;
public class SSMAbout extends JFrame {
// IMPORTANT: Source code between BEGIN/END comment pair will be regenerated
// every time the form is saved. All manual changes will be overwritten.
// BEGIN GENERATED CODE
	// member declarations
	javax.swing.JPanel onTopOfAllPanel = new javax.swing.JPanel();
	javax.swing.JLabel versionLabel = new javax.swing.JLabel();
	javax.swing.JLabel authorLabel = new javax.swing.JLabel();
	javax.swing.JLabel dateLabel = new javax.swing.JLabel();
	javax.swing.JTextField versionTextField = new javax.swing.JTextField();
	javax.swing.JTextField dateTextField = new javax.swing.JTextField();
	javax.swing.JTextField authorTextField = new javax.swing.JTextField();
	javax.swing.JLabel authorEmailLabel = new javax.swing.JLabel();
	javax.swing.JTextField authorEmailTextField = new javax.swing.JTextField();
// END GENERATED CODE

	public SSMAbout()
	{
	    try { initComponents() ; } catch( Exception ex ) {}
	    setVisible( true ) ;
	}

	public void initComponents() throws Exception
	{
// IMPORTANT: Source code between BEGIN/END comment pair will be regenerated
// every time the form is saved. All manual changes will be overwritten.
// BEGIN GENERATED CODE
		// the following code sets the frame's initial state
		onTopOfAllPanel.setForeground(null);
		onTopOfAllPanel.setLocation(new java.awt.Point(0, 0));
		onTopOfAllPanel.setVisible(true);
		onTopOfAllPanel.setBackground(null);
		onTopOfAllPanel.setFont(null);
		onTopOfAllPanel.setLayout(null);
		onTopOfAllPanel.setOpaque(false);
		onTopOfAllPanel.setSize(new java.awt.Dimension(320, 120));

		versionLabel.setText("Version:");
		versionLabel.setLocation(new java.awt.Point(10, 10));
		versionLabel.setVisible(true);
		versionLabel.setFont(null);
		versionLabel.setSize(new java.awt.Dimension(80, 20));

		authorLabel.setText("Author & :");
		authorLabel.setLocation(new java.awt.Point(10, 50));
		authorLabel.setVisible(true);
		authorLabel.setFont(null);
		authorLabel.setSize(new java.awt.Dimension(80, 20));

		dateLabel.setText("Date:");
		dateLabel.setLocation(new java.awt.Point(10, 30));
		dateLabel.setVisible(true);
		dateLabel.setFont(null);
		dateLabel.setSize(new java.awt.Dimension(80, 20));

		versionTextField.setLocation(new java.awt.Point(90, 10));
		versionTextField.setVisible(true);
		versionTextField.setFont(null);
		versionTextField.setSize(new java.awt.Dimension(220, 20));
		versionTextField.setEditable(false);

		dateTextField.setLocation(new java.awt.Point(90, 30));
		dateTextField.setVisible(true);
		dateTextField.setFont(null);
		dateTextField.setSize(new java.awt.Dimension(220, 20));
		dateTextField.setEditable(false);

		authorTextField.setLocation(new java.awt.Point(90, 50));
		authorTextField.setVisible(true);
		authorTextField.setFont(null);
		authorTextField.setSize(new java.awt.Dimension(220, 20));
		authorTextField.setEditable(false);

		authorEmailLabel.setText("Email:");
		authorEmailLabel.setLocation(new java.awt.Point(10, 70));
		authorEmailLabel.setVisible(true);
		authorEmailLabel.setFont(null);
		authorEmailLabel.setSize(new java.awt.Dimension(80, 20));

		authorEmailTextField.setLocation(new java.awt.Point(90, 70));
		authorEmailTextField.setVisible(true);
		authorEmailTextField.setFont(null);
		authorEmailTextField.setSize(new java.awt.Dimension(220, 20));
		authorEmailTextField.setEditable(false);

		setLocation(new java.awt.Point(0, 0));
		setTitle("About the Simple Stack Machine");
		setResizable(false);
		setFont(new java.awt.Font("SansSerif", 0, 10));
		getContentPane().setLayout(null);
		setSize(new java.awt.Dimension(321, 121));
		getContentPane().add(onTopOfAllPanel);
		getContentPane().add(versionLabel);
		getContentPane().add(authorLabel);
		getContentPane().add(dateLabel);
		getContentPane().add(versionTextField);
		getContentPane().add(dateTextField);
		getContentPane().add(authorTextField);
		getContentPane().add(authorEmailLabel);
		getContentPane().add(authorEmailTextField);


		onTopOfAllPanel.addMouseListener(new java.awt.event.MouseAdapter() {
			public void mouseClicked(java.awt.event.MouseEvent e) {
				onTopOfAllPanelMouseClicked(e);
			}
		});
		addWindowListener(new java.awt.event.WindowAdapter() {
			public void windowClosing(java.awt.event.WindowEvent e) {
				thisWindowClosing(e);
			}
		});
// END GENERATED CODE

        versionTextField.setText( Config.version() ) ;
        dateTextField.setText( Config.versionDate() ) ;
        authorTextField.setText( Config.author() ) ;
        authorEmailTextField.setText( Config.authorEmail() ) ;
	}
  
  	/*
  	private boolean mShown = false;
  	
	public void addNotify() 
	{
		super.addNotify();
		
		if (mShown)
			return;
			
		// resize frame to account for menubar
		JMenuBar jMenuBar = getJMenuBar();
		if (jMenuBar != null) {
			int jMenuBarHeight = jMenuBar.getPreferredSize().height;
			Dimension dimension = getSize();
			dimension.height += jMenuBarHeight;
			setSize(dimension);
		}

		mShown = true;
	}
	*/

	private void done()
	{
		setVisible(false);
		dispose();
	}
	
	// Close the window when the close box is clicked
	void thisWindowClosing(java.awt.event.WindowEvent e)
	{
		done() ;
	}

	public void onTopOfAllPanelMouseClicked(java.awt.event.MouseEvent e)
	{
		done() ;
	}
	
	
}
\ No newline at end of file
+package nl.uu.cs.ssmui;
import java.awt.*;import java.awt.event.*;import javax.swing.*;
import nl.uu.cs.ssm.* ;
public class SSMAbout extends JFrame {

	private static final long serialVersionUID = 1L ;
// IMPORTANT: Source code between BEGIN/END comment pair will be regenerated
// every time the form is saved. All manual changes will be overwritten.
// BEGIN GENERATED CODE
	// member declarations
	javax.swing.JPanel onTopOfAllPanel = new javax.swing.JPanel();
	javax.swing.JLabel versionLabel = new javax.swing.JLabel();
	javax.swing.JLabel authorLabel = new javax.swing.JLabel();
	javax.swing.JLabel dateLabel = new javax.swing.JLabel();
	javax.swing.JTextField versionTextField = new javax.swing.JTextField();
	javax.swing.JTextField dateTextField = new javax.swing.JTextField();
	javax.swing.JTextField authorTextField = new javax.swing.JTextField();
	javax.swing.JLabel authorEmailLabel = new javax.swing.JLabel();
	javax.swing.JTextField authorEmailTextField = new javax.swing.JTextField();
// END GENERATED CODE

	public SSMAbout()
	{
	    try { initComponents() ; } catch( Exception ex ) {}
	    setVisible( true ) ;
	}

	public void initComponents() throws Exception
	{
// IMPORTANT: Source code between BEGIN/END comment pair will be regenerated
// every time the form is saved. All manual changes will be overwritten.
// BEGIN GENERATED CODE
		// the following code sets the frame's initial state
		onTopOfAllPanel.setForeground(null);
		onTopOfAllPanel.setLocation(new java.awt.Point(0, 0));
		onTopOfAllPanel.setVisible(true);
		onTopOfAllPanel.setBackground(null);
		onTopOfAllPanel.setFont(null);
		onTopOfAllPanel.setLayout(null);
		onTopOfAllPanel.setOpaque(false);
		onTopOfAllPanel.setSize(new java.awt.Dimension(320, 120));

		versionLabel.setText("Version:");
		versionLabel.setLocation(new java.awt.Point(10, 10));
		versionLabel.setVisible(true);
		versionLabel.setFont(null);
		versionLabel.setSize(new java.awt.Dimension(80, 20));

		authorLabel.setText("Author & :");
		authorLabel.setLocation(new java.awt.Point(10, 50));
		authorLabel.setVisible(true);
		authorLabel.setFont(null);
		authorLabel.setSize(new java.awt.Dimension(80, 20));

		dateLabel.setText("Date:");
		dateLabel.setLocation(new java.awt.Point(10, 30));
		dateLabel.setVisible(true);
		dateLabel.setFont(null);
		dateLabel.setSize(new java.awt.Dimension(80, 20));

		versionTextField.setLocation(new java.awt.Point(90, 10));
		versionTextField.setVisible(true);
		versionTextField.setFont(null);
		versionTextField.setSize(new java.awt.Dimension(220, 20));
		versionTextField.setEditable(false);

		dateTextField.setLocation(new java.awt.Point(90, 30));
		dateTextField.setVisible(true);
		dateTextField.setFont(null);
		dateTextField.setSize(new java.awt.Dimension(220, 20));
		dateTextField.setEditable(false);

		authorTextField.setLocation(new java.awt.Point(90, 50));
		authorTextField.setVisible(true);
		authorTextField.setFont(null);
		authorTextField.setSize(new java.awt.Dimension(220, 20));
		authorTextField.setEditable(false);

		authorEmailLabel.setText("Email:");
		authorEmailLabel.setLocation(new java.awt.Point(10, 70));
		authorEmailLabel.setVisible(true);
		authorEmailLabel.setFont(null);
		authorEmailLabel.setSize(new java.awt.Dimension(80, 20));

		authorEmailTextField.setLocation(new java.awt.Point(90, 70));
		authorEmailTextField.setVisible(true);
		authorEmailTextField.setFont(null);
		authorEmailTextField.setSize(new java.awt.Dimension(220, 20));
		authorEmailTextField.setEditable(false);

		setLocation(new java.awt.Point(0, 0));
		setTitle("About the Simple Stack Machine");
		setResizable(false);
		setFont(new java.awt.Font("SansSerif", 0, 10));
		getContentPane().setLayout(null);
		setSize(new java.awt.Dimension(321, 121));
		getContentPane().add(onTopOfAllPanel);
		getContentPane().add(versionLabel);
		getContentPane().add(authorLabel);
		getContentPane().add(dateLabel);
		getContentPane().add(versionTextField);
		getContentPane().add(dateTextField);
		getContentPane().add(authorTextField);
		getContentPane().add(authorEmailLabel);
		getContentPane().add(authorEmailTextField);


		onTopOfAllPanel.addMouseListener(new java.awt.event.MouseAdapter() {
			public void mouseClicked(java.awt.event.MouseEvent e) {
				onTopOfAllPanelMouseClicked(e);
			}
		});
		addWindowListener(new java.awt.event.WindowAdapter() {
			public void windowClosing(java.awt.event.WindowEvent e) {
				thisWindowClosing(e);
			}
		});
// END GENERATED CODE

        versionTextField.setText( Config.version() ) ;
        dateTextField.setText( Config.versionDate() ) ;
        authorTextField.setText( Config.author() ) ;
        authorEmailTextField.setText( Config.authorEmail() ) ;
	}
  
  	/*
  	private boolean mShown = false;
  	
	public void addNotify() 
	{
		super.addNotify();
		
		if (mShown)
			return;
			
		// resize frame to account for menubar
		JMenuBar jMenuBar = getJMenuBar();
		if (jMenuBar != null) {
			int jMenuBarHeight = jMenuBar.getPreferredSize().height;
			Dimension dimension = getSize();
			dimension.height += jMenuBarHeight;
			setSize(dimension);
		}

		mShown = true;
	}
	*/

	private void done()
	{
		setVisible(false);
		dispose();
	}
	
	// Close the window when the close box is clicked
	void thisWindowClosing(java.awt.event.WindowEvent e)
	{
		done() ;
	}

	public void onTopOfAllPanelMouseClicked(java.awt.event.MouseEvent e)
	{
		done() ;
	}
	
	
}
\ No newline at end of file