A state machine for an assembler capable of processing structured assembly language is disclosed. The state machine for an assembler capable of processing structured assembly language IF constructs includes five states, namely, an IF state, an ELSE state, an END_—IF state, an ELSE_—IF state, and a SETUP_—IF state. In response to recognizing a SETUP_—IF clause during the IF state or the ELSE_—IF state, the process transitions to the SETUP_—IF state. In response to recognizing an ELSE_—IF clause during the SETUP_—IF state, the process transitions to the ELSE_—IF state.