Abstract: An improved system for performing call and return operations in a computer system in which every call and return operation changes the program counter and the frame pointer but some call and return operations change other state. Included in the state which may change in the computer system of the present invention is addresses used in calculating other addresses, an identifier specifying which instruction set the processor is executing, and protection state which determines what data may be accessed during execution of a procedure. In the system, the state saved and restored in the call and return operations is divided into basic state saved and restored on every call and return and extended state saved and restored on only some calls and returns. The frame associated with an execution accordingly contains either saved basic state or saved basic state and saved extended state.