A method and apparatus for sending thread-execution-state-sensitive supervisory commands to a simultaneous multi-threaded processor provides a mechanism for sending supervisory commands that must be executed only for live threads. The commands may be sent from a service processor or another primary processor in the system or may be supplied by the processor itself through supervisory software control. Since the state of execution of one or more threads may change dynamically within a processor core, an external processor will not know the thread execution state at the time the command operates. The method and apparatus provide a command set and logic that supports selective execution of particular commands directed at "alive" threads (or threads in some other determinable execution state), whereby the command is performed only on resources and/or execution units depending on the actual state of thread execution when the command operates within the processor.