System for simultaneously accessing one or more stack elements by

Abstract

Embodiments of the present invention provide a stack renaming method and apparatus for stack based processors. Using principles of the present invention, a stack can be accessed simultaneously by one or more functional units in a stack processor. The stack apparatus includes a stack renaming unit capable of renaming a logical stack address to a real stack address. Each logical stack address corresponds to a storage element in the stack renaming unit which stores a real stack address. A circular counter is used in the stack renaming unit to sequentially cycle through each of the logical stack addresses. The real stack addresses corresponding to each of the logical stack addresses can be stored out of order in the stack renaming unit. A stack control unit is coupled to the stack renaming unit and provides one or more control signals to the stack renaming unit and coordinates the operation of the stack renaming unit within the stack apparatus. A stack memory circuit coupled to the stack renaming unit receives the real stack address and generates a data value to be used in a functional unit. The real address is provided to a functional unit by a real address output port coupled to the stack renaming unit. As long as there are no data dependencies or structural dependences, a functional unit is able to operate on the data value associated with the real address while other functional units may be accessing and using other stack values.