| (1) A thread models a concurrent task or an active object, that is, a schedulable unit that can execute concurrently with other threads. Each thread represents a sequential flow of control that executes instructions within a binary image produced from the source text. One or more AADL threads may be implemented in a single operating system thread. A thread always executes within the virtual address space of a process; that is, the binary images making up the virtual address space must be loaded before any thread can execute in that virtual address space. Threads are dispatched; that is, their execution is initiated periodically by the clock or by the arrival of data or events on ports, or by the arrival of subprogram calls from other threads. | definition thread_thread2system_valid:: “(′s, ′Dispatcher, ′Port, ′Dataaccess, ′Subpaccess, ′Parameter, ′Subprogramcall, ′Subprogramcalls, ′Connection, ′Data, ′Subprogram, ′Thread, ′Process, ′System, ′BehaviorAnnex) AADL_model ⇒ bool”
where “thread_thread2system_valid m ≡ ∀sys. ∃sc1 sc2. (if ((system_im m)≠None ∧ (the (system_im m) sys)≠None ∧ (impl_subcomps (get_sysimpl m sys))≠{})
then (sc1∈(impl_subcomps (get_sysimpl m sys))
⟶ (case sc1 of SCThd _ ⇒ True
| SCPro pro ⇒ (if ((process_im m)≠None ∧ (the (process_im m) pro)≠None ∧ (impl_subcomps (get_proimpl m pro))≠{})
then (sc2∈(impl_subcomps (get_proimpl m pro)) ⟶
(case sc2 of SCThd _ ⇒ True
| _ ⇒ False))
else False)
| _ ⇒ False))
else False)” definition thread_thread2process_valid:: “(′s, ′Dispatcher, ′Port, ′Dataaccess, ′Subpaccess, ′Parameter, ′Subprogramcall, ′Subprogramcalls, ′Connection, ′Data, ′Subprogram, ′Thread, ′Process, ′System, ′BehaviorAnnex) AADL_model ⇒ bool”
where “thread_thread2process_valid m ≡ ∀pro. ∃sc. (if ((process_im m)≠None ∧ (the (process_im m) pro)≠None ∧ (impl_subcomps (get_proimpl m pro))≠{})
then (sc∈(impl_subcomps (get_proimpl m pro)) ⟶ (case sc of SCThd _ ⇒ True
| _ ⇒ False))
else False)” |
