The Virtual PORT registers map the most frequently used regular PORT registers
         into the I/O Register space with single-cycle bit access. 
Access to
            the Virtual PORT registers has the same outcome as access to the regular registers but
            allows for memory specific instructions, such as bit manipulation instructions, which
            cannot be used in the extended I/O Register space where the regular PORT registers
            reside.
         The following table shows the
         mapping between the PORT and VPORT registers.
Table 16-1. Virtual Port Mapping| Regular PORT Register | Mapped to Virtual PORT Register | 
|---|
| PORTx.DIR | VPORTx.DIR | 
| PORTx.OUT | VPORTx.OUT | 
| PORTx.IN | VPORTx.IN | 
| PORTx.INTFLAGS | VPORTx.INTFLAGS |