Method and apparatus for executing a flush rs instruction to synchronize a register stack with instructions executed by a processor

Abstract

A processor that is configured to execute a programmed flow of instructions is disclosed. The processor includes a register stack (RS). The register stack (RS) has a portion allocated for dirty registers. The processor also includes a register stack engine (RSE) to exchange information, in one of an instruction execution dependent and independent modes, between the RS and storage area. The processor also includes a flush control circuit to generate to the RSE, dependent of instruction execution a signal, in response to which, the RSE spills to the storage area all dirty registers, from the RS. A computer implemented method in a processor is also provided. The processor includes a register stack (RS) device that includes a portion allocated for dirty registers. The portion is defined by first and second physical register numbers. The processor further includes a register stack engine (RSE) to exchange information in one of an instruction execution dependent and independent modes between a storage area and the RS. The storage area is defined by first and second pointers. At step a, it is determined whether the first and second physical register numbers have a predetermined logical relationship relative to each other. At step b, it is stored by the RSE, a register of the portion of the RS to a first location in the storage area corresponding to the first pointer, if the first and second physical register numbers have a predetermined logical relationship relative to each other. At step c, it is pointed to a next location in the storage area and the first physical register number is incremented. Therefore, the RSE is synchronized with the instructions executed by the processor.