physicaladdressspace.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。

        
        public byte getByte(int offset)
        {
            offset = baseAddress | offset;
            return memory.getByte(offset);
        }
        
        public short getWord(int offset)
        {
            offset = baseAddress | offset;
            return memory.getWord(offset);
        }
        
        public int getDoubleWord(int offset)
        {
            offset = baseAddress | offset;
            return memory.getDoubleWord(offset);   
        }

        public long getQuadWord(int offset)
        {
            offset = baseAddress | offset;
            return memory.getQuadWord(offset);   
        }

        public long getLowerDoubleQuadWord(int offset)
        {
            offset = baseAddress | offset;
            return memory.getQuadWord(offset);   
        }
        
        public long getUpperDoubleQuadWord(int offset)
        {
            offset += 8;
            offset = baseAddress | offset;
            return memory.getQuadWord(offset);
        }
        
        public void setByte(int offset, byte data)
        {
            offset = baseAddress | offset;
            memory.setByte(offset, data);
        }
        
        public void setWord(int offset, short data)
        {
            offset = baseAddress | offset;
            memory.setWord(offset, data);
        }
        
        public void setDoubleWord(int offset, int data)
        {
            offset = baseAddress | offset;
            memory.setDoubleWord(offset, data);
        }

        public void setQuadWord(int offset, long data)
        {
            offset = baseAddress | offset;
            memory.setQuadWord(offset, data);
        }

        public void setLowerDoubleQuadWord(int offset, long data)
        {
            offset = baseAddress | offset;
            memory.setQuadWord(offset, data);
        }
        
        public void setUpperDoubleQuadWord(int offset, long data)
        {
            offset += 8;
            offset = baseAddress | offset;
            memory.setQuadWord(offset, data);
        }

	public int execute(Processor cpu, int offset)
	{
	    offset = baseAddress | offset;
	    return memory.execute(cpu, offset);
	}
	
	public CodeBlock decodeCodeBlockAt(Processor cpu, int offset)
	{
	    offset = baseAddress | offset;
	    CodeBlock block= memory.decodeCodeBlockAt(cpu, offset);
	    if(block!=null)
		System.out.println(getClass().getName()+":1");
	    else
		System.out.println(getClass().getName()+":0");
	    return block;
	}
    }

    public void clear()
    {
        for (int i=0; i<quickNonA20MaskedIndex.length; i++)
            quickNonA20MaskedIndex[i].clear();

	for (int i = 0; i < nonA20MaskedIndex.length; i++) {
	    Memory[] subArray = nonA20MaskedIndex[i];
	    try {
		for (int j = 0; j < subArray.length; j++) {
		    try {
			subArray[j].clear();
		    } catch (NullPointerException e) {}
		}
	    } catch (NullPointerException e) {}
	}
    }
    
    public void unmap(int start, int length)
    {
        if ((start % BLOCK_SIZE) != 0)
            throw new IllegalStateException("Cannot deallocate memory starting at "+Integer.toHexString(start)+"; this is not block aligned at "+BLOCK_SIZE+" boundaries");
        if ((length % BLOCK_SIZE) != 0)
            throw new IllegalStateException("Cannot deallocate memory in partial blocks. "+length+" is not a multiple of "+BLOCK_SIZE);
	
        for (int i=start; i<start+length; i+=BLOCK_SIZE)
        {
	    if (getMemoryBlockAt(i) != UNCONNECTED) 
                mappedRegionCount--;
	    setMemoryBlockAt(i, UNCONNECTED);
        }
    }

    public void mapMemoryRegion(Memory underlying, int start, int length)
    {
        if (underlying.getSize() < length)
            throw new IllegalStateException("Underlying memory (length="+underlying.getSize()+") is too short for mapping into region "+length+" bytes long");
        if ((start % BLOCK_SIZE) != 0)
            throw new IllegalStateException("Cannot map memory starting at "+Integer.toHexString(start)+"; this is not aligned to "+BLOCK_SIZE+" blocks");
        if ((length % BLOCK_SIZE) != 0)
            throw new IllegalStateException("Cannot map memory in partial blocks: "+length+" is not a multiple of "+BLOCK_SIZE);

        unmap(start, length);

        long s = 0xFFFFFFFFl & start;
        for (long i=s; i<s+length; i += BLOCK_SIZE)
        {
            Memory w = new MapWrapper(underlying, (int)(i-s));
	    setMemoryBlockAt((int)i, w);
            mappedRegionCount++;
        }
    }

    public void allocateMemory(int start, Memory block)
    {
        if ((start % BLOCK_SIZE) != 0)
            throw new IllegalStateException("Cannot allocate memory starting at "+Integer.toHexString(start)+"; this is not aligned to "+BLOCK_SIZE+" blocks");
        if (block.getSize() != BLOCK_SIZE)
            throw new IllegalStateException("Can only allocate memory in blocks of "+BLOCK_SIZE);
        
        unmap(start, BLOCK_SIZE);

        long s = 0xFFFFFFFFl & start;
	setMemoryBlockAt((int)s, block);
        mappedRegionCount++;
    }


    public static final class UnconnectedMemoryBlock extends Memory
    {
	public void clear() {}

	public void clear(int start, int length) {}

	public void copyContentsInto(int address, byte[] buffer, int off, int len) {}
	
	public void copyContentsFrom(int address, byte[] buffer, int off, int len)
	{
	    len = Math.min(BLOCK_SIZE - address, Math.min(buffer.length - off, len));
	    for (int i=off; i<len; i++)
		buffer[i] = getByte(0);
	}

	public long getSize()
	{
	    return BLOCK_SIZE;
	}
	
	public byte getByte(int offset)
	{
	    return (byte) 0xFF;
	}	

	public short getWord(int offset)
	{
	    return (short) 0xFFFF;
	}

	public int getDoubleWord(int offset)
	{
	    return 0xFFFFFFFF;
	}

        public long getQuadWord(int offset)
        {
            return -1l;
        }

        public long getLowerDoubleQuadWord(int offset)
        {
            return -1l;
        }

        public long getUpperDoubleQuadWord(int offset)
        {
            return -1l;
        }

	public void setByte(int offset, byte data) {}

	public void setWord(int offset, short data) {}

	public void setDoubleWord(int offset, int data) {}

        public void setQuadWord(int offset, long data) {}
        
        public void setLowerDoubleQuadWord(int offset, long data) {}
        
        public void setUpperDoubleQuadWord(int offset, long data) {}

	public int execute(Processor cpu, int offset)
	{
	    throw new IllegalStateException("Trying to execute in Unconnected Block @ 0x" + Integer.toHexString(offset));
	}
	
	public CodeBlock decodeCodeBlockAt(Processor cpu, int offset)
	{
	    throw new IllegalStateException("Trying to execute in Unconnected Block @ 0x" + Integer.toHexString(offset));
	}
    }

    public void reset()
    {
        clear();
	setGateA20State(false);
	linearAddr = null;
    }

    public boolean updated()
    {
        return true;
    }

    public void updateComponent(HardwareComponent component)
    {    }
    
    public boolean initialised()
    {
        return (linearAddr != null);
    }

    public void acceptComponent(HardwareComponent component)
    {
	if (component instanceof LinearAddressSpace)
	    linearAddr = (LinearAddressSpace) component;
    }

    public String toString()
    {
        return "Physical Address Bus";
    }
    
    private Memory getMemoryBlockAt(int i)
    {
	try {
	    return quickIndex[i >>> INDEX_SHIFT];
	} catch (ArrayIndexOutOfBoundsException e) {
	    try {
		return index[i >>> TOP_INDEX_SHIFT][(i >>> BOTTOM_INDEX_SHIFT) & BOTTOM_INDEX_MASK];
	    } catch (NullPointerException n) {
		return UNCONNECTED;
	    }
	}
    }
    
    private void setMemoryBlockAt(int i, Memory b)
    {
	try {
	    int idx = i >>> INDEX_SHIFT;
	    quickNonA20MaskedIndex[idx] = b;
	    if ((idx & (GATEA20_MASK >>> INDEX_SHIFT)) == idx) {
		quickA20MaskedIndex[idx] = b;
		quickA20MaskedIndex[idx | ((~GATEA20_MASK) >>> INDEX_SHIFT)] = b;
	    }
	} catch (ArrayIndexOutOfBoundsException e) {
	    try {
		nonA20MaskedIndex[i >>> TOP_INDEX_SHIFT][(i >>> BOTTOM_INDEX_SHIFT) & BOTTOM_INDEX_MASK] = b;
	    } catch (NullPointerException n) {
		nonA20MaskedIndex[i >>> TOP_INDEX_SHIFT] = new Memory[BOTTOM_INDEX_SIZE];
		nonA20MaskedIndex[i >>> TOP_INDEX_SHIFT][(i >>> BOTTOM_INDEX_SHIFT) & BOTTOM_INDEX_MASK] = b;
	    }
	    
	    if ((i & GATEA20_MASK) == i) {
		try {
		    a20MaskedIndex[i >>> TOP_INDEX_SHIFT][(i >>> BOTTOM_INDEX_SHIFT) & BOTTOM_INDEX_MASK] = b;
		} catch (NullPointerException n) {
		    a20MaskedIndex[i >>> TOP_INDEX_SHIFT] = new Memory[BOTTOM_INDEX_SIZE];
		    a20MaskedIndex[i >>> TOP_INDEX_SHIFT][(i >>> BOTTOM_INDEX_SHIFT) & BOTTOM_INDEX_MASK] = b;
		}

		int modi = i | ~GATEA20_MASK;
		try {
		    a20MaskedIndex[modi >>> TOP_INDEX_SHIFT][(modi >>> BOTTOM_INDEX_SHIFT) & BOTTOM_INDEX_MASK] = b;
		} catch (NullPointerException n) {
		    a20MaskedIndex[modi >>> TOP_INDEX_SHIFT] = new Memory[BOTTOM_INDEX_SIZE];
		    a20MaskedIndex[modi >>> TOP_INDEX_SHIFT][(modi >>> BOTTOM_INDEX_SHIFT) & BOTTOM_INDEX_MASK] = b;
		}
	    }
	}
    }

    public void timerCallback() {}
}