EFFICIENT SAVING AND RESTORING STATE IN TASK SWITCHING

摘要

The present invention discloses a method and apparatus for saving and restoring registers. A single instruction is decoded. The single instruction moves contents of a plurality of registers associated with a functional unit in a processor to a memory; the processor operates under a plurality of operational modes and operand sizes. The single instruction arranges the contents in the memory according to a predetermined format into a plurality of groups, each group is aligned at an address boundary which corresponds to a multiple of 2N bytes. The predetermined format is constant for the plurality of operational modes and operand sizes. The single instruction retains the contents of the plurality of registers after moving.