A processing device employs a stack memory in a region of an external memory. The processing device has a stack pointer register to store a current top address for the stack memory. One of several techniques is used to determine which portion or portions of the external memory correspond to the stack region. A more efficient memory policy is implemented, whereby pushes to the stack do not have to read data from the external memory in to a cache, and whereby pops from the stack do not cause stale stack data to be written back from the cache to the external memory.