Apparatus and method for efficient call/return emulation using a dual return stack buffer

An apparatus and method for a dual return stack buffer (RSB) for use in binary translation systems. For example, one embodiment of a processor comprises: a dual return stack buffer (DRSB) comprising a native RSB and an extended RSB (XRSB), the dual RSB to be used within a binary translation execution environment in which guest call-return instruction sequences are translated to native call-return instruction sequences to be executed directly by the processor; the native RSB to store native return addresses associated with the native call-return instruction sequences; and the XRSB to store emulated return addresses associated with the guest call-return instruction sequences, wherein each native return address stored in the RSB is associated with an emulated return address stored in the XRSB.