gm2-libs-coroutines/Executive (The GNU Modula-2 Compiler) (original) (raw)

DEFINITION MODULE Executive ;

EXPORT QUALIFIED SEMAPHORE, DESCRIPTOR, InitProcess, KillProcess, Resume, Suspend, InitSemaphore, Wait, Signal, WaitForIO, Ps, GetCurrentProcess, RotateRunQueue, ProcessName, DebugProcess ;

TYPE SEMAPHORE ; (* defines Dijkstra's semaphores ) DESCRIPTOR ; ( handle onto a process *)

(* InitProcess - initializes a process which is held in the suspended state. When the process is resumed it will start executing procedure, p. The process has a maximum stack size of, StackSize, bytes and its textual name is, Name. The StackSize should be at least 5000 bytes. *)

PROCEDURE InitProcess (p: PROC; StackSize: CARDINAL; Name: ARRAY OF CHAR) : DESCRIPTOR ;

(* KillProcess - kills the current process. Notice that if InitProcess is called again, it might reuse the DESCRIPTOR of the killed process. It is the responsibility of the caller to ensure all other processes understand this process is different. *)

PROCEDURE KillProcess ;

(* Resume - resumes a suspended process. If all is successful then the process, p, is returned. If it fails then NIL is returned. *)

PROCEDURE Resume (d: DESCRIPTOR) : DESCRIPTOR ;

(* Suspend - suspend the calling process. The process can only continue running if another process Resumes it. *)

PROCEDURE Suspend ;

(* InitSemaphore - creates a semaphore whose initial value is, v, and whose name is, Name. *)

PROCEDURE InitSemaphore (v: CARDINAL; Name: ARRAY OF CHAR) : SEMAPHORE ;

(* Wait - performs dijkstra's P operation on a semaphore. A process which calls this procedure will wait until the value of the semaphore is > 0 and then it will decrement this value. *)

PROCEDURE Wait (s: SEMAPHORE) ;

(* Signal - performs dijkstra's V operation on a semaphore. A process which calls the procedure will increment the semaphores value. *)

PROCEDURE Signal (s: SEMAPHORE) ;

(* WaitForIO - waits for an interrupt to occur on vector, VectorNo. *)

PROCEDURE WaitForIO (VectorNo: CARDINAL) ;

(* Ps - displays a process list together with process status. *)

PROCEDURE Ps ;

(* GetCurrentProcess - returns the descriptor of the current running process. *)

PROCEDURE GetCurrentProcess () : DESCRIPTOR ;

(* RotateRunQueue - rotates the process run queue. It does not call the scheduler. *)

PROCEDURE RotateRunQueue ;

(* ProcessName - displays the name of process, d, through DebugString. *)

PROCEDURE ProcessName (d: DESCRIPTOR) ;

(* DebugProcess - gdb debug handle to enable users to debug deadlocked semaphore processes. *)

PROCEDURE DebugProcess (d: DESCRIPTOR) ;

END Executive.