<p>One aspect of the present invention provides processor comprising: an execution unit arranged to execute a sequence of instructions each comprising a respective opcode; and a counter coupled to the execution unit and arranged to generate a periodically updated counter value during execution. The execution unit comprises logic configured to identify an opcode representing a trap-if-late instruction in said sequence, and in response to execute the trap-if-late instruction by comparing a target value to the counter value and generating an exception on condition that the counter value represents a time that is late relative to said target value. Another aspect provides a compiler for inserting trap-if-late instructions based on timing constraints in higher-level code.</p>
