Medium access control (MAC) implementations control access of network devices to a transmission medium. For emerging communication protocols, the MAC is typically implemented in software, to enable adaptation to evolving de-facto or industry standards. Software MAC implementations are typically realized as state machines, executing code related to successive MAC states within periodic interrupts. This software construct yields minimal memory footprint and energy efficiency, but the resulting implementations are often tightly coupled to the platform's system software, and are thus nonportable across hardware and system platforms. This article presents an architecture that decouples MAC and system software, enabling portability, while preserving software efficiency.