1. A method for executing instructions in a digital system having a processor, comprising the steps of: fetching and decoding a first instruction of a first type, wherein a first type instruction requires use of a least a first register of the processor; saving first data stored in the first register automatically in response to the step of decoding the first instruction; executing the first instruction in a manner that uses the first register; and restoring the first register with the saved first data automatically after the step of executing.