1. A method for operating a digital processor by accessing a current instruction, the method comprising: determining if a virtual address associated with the current instruction belongs to first or second alias space wherein: a first operating mode is associated with the first alias space and a second operating mode is associated with the second alias space; and at least one virtual address in the first alias space and at least one virtual address in the second alias space correspond to a single physical-memory address; and setting the processor in the first or second operating mode according to alias space to which the virtual address associated with the current instruction belongs.