Gannet is an architecture for service-level reconfigurable Systems-on-Chip. From a computing perspective, the Gannet architecture can be regarded as a distributed demand-driven dataflow processor. The "Gannet machine" uses a functional language as its machine language. The main feature of this language is that every language construct is provided by a "service", which is mapped to a functional construct. In this talk we will present the operational semantics of the Gannet machine language using Felleisen's rewriting semantics.