A2OS/source/Unix.Environment.Mod

(* Runtime environment for Unix *)
(* Copyright (C) Florian Negele *)

MODULE Environment;

IMPORT SYSTEM, Activities, Counters, Unix, Processors, Queues, Timer, Trace;

CONST IsNative* = FALSE;

CONST Running* = 0; ShuttingDown* = 1; Rebooting* = 2;

VAR status* := 0: WORD;
VAR clock: Timer.Counter;
VAR milliseconds: Timer.Counter;
VAR sleepingQueue: Queues.Queue;

PROCEDURE {NORETURN} Abort-;
BEGIN {UNCOOPERATIVE, UNCHECKED}
	IF Activities.GetCurrentActivity () # NIL THEN Activities.TerminateCurrentActivity END;
	Exit (1);
END Abort;

PROCEDURE Shutdown*;
BEGIN {UNCOOPERATIVE, UNCHECKED}
	Trace.StringLn ("system: shutting down...");
	Trace.StringLn ("system: shutting down...");
END Shutdown;

PROCEDURE Reboot*;
BEGIN {UNCOOPERATIVE, UNCHECKED}
	Shutdown;
	ASSERT (CAS (status, ShuttingDown, Rebooting) = ShuttingDown);
END Reboot;

PROCEDURE {NORETURN} Exit- (status: WORD);
BEGIN {UNCOOPERATIVE, UNCHECKED}
	Unix.exit (status);
END Exit;

PROCEDURE Clock- (): LONGINT;
BEGIN {UNCOOPERATIVE, UNCHECKED}
	RETURN LONGINT ((Timer.GetCounter () - clock) / milliseconds);
END Clock;

PROCEDURE Sleep- (milliseconds: LONGINT);
VAR nextActivity: Activities.Activity;
BEGIN {UNCOOPERATIVE, UNCHECKED}
	INC (milliseconds, Clock ());
	Counters.Inc (Activities.awaiting);
	WHILE Clock () - milliseconds < 0 DO
		IF Activities.Select (nextActivity, Activities.IdlePriority) THEN
			Activities.SwitchTo (nextActivity, Enqueue, NIL);
			Activities.FinalizeSwitch;
		END;
	END;
	Counters.Dec (Activities.awaiting);
END Sleep;

PROCEDURE Enqueue (previous {UNTRACED}: Activities.Activity; argument: ADDRESS);
VAR item: Queues.Item;
BEGIN {UNCOOPERATIVE, UNCHECKED}
	Queues.Enqueue (previous, sleepingQueue);
END Enqueue;

PROCEDURE GetInit- (n: SIZE; VAR val: LONGINT);
BEGIN val := 0;
END GetInit;

PROCEDURE Initialize-;
BEGIN {UNCOOPERATIVE, UNCHECKED}
	clock := Timer.GetCounter ();
	milliseconds := Timer.GetFrequency () DIV 1000;
END Initialize;

PROCEDURE Terminate-;
BEGIN {UNCOOPERATIVE, UNCHECKED}
END Terminate;

END Environment.