Saving a program counter value as the return address in an arbitrary general purpose register

摘要

An information processor comprises an instruction decoder for executing a subroutine calling instruction including designation of a general-purpose register for calling a subroutine, a circuit for selecting a specific general-purpose register designated by an instruction based on a result of the execution of a subroutine calling instruction among a plurality of general-purpose registers, and a circuit for saving, in a selected general-purpose register, a value obtained by adding a length of a subroutine calling instruction to a program counter value as a return address.