In one embodiment, a processor can operate in multiple modes, including a direct execution mode and an emulation execution mode. More specifically, the processor may operate in a partial emulation model in which source instruction set architecture (ISA) instructions are directly handled in the direct execution mode and translated code generated by an emulation engine is handled in the emulation execution mode. Embodiments may also provide for efficient transitions between the modes using information that can be stored in one or more storages of the processor and elsewhere in a system. Other embodiments are described and claimed.