Copyright (C) 1994, Digital Equipment Corp. UNSAFE MODULE--------------------------------------------------- process termination ---; IMPORT WinBase, WinNT, WinCon, WinDef; RTOS
PROCEDURE------------------------------------------------------------- allocator ---Exit (n: INTEGER) = BEGIN WinBase.ExitProcess (n); END Exit; PROCEDURECrash () = VAR ptr := LOOPHOLE(-99, UNTRACED REF INTEGER); BEGIN ptr^ := 99; (* try to get to the debugger... *) WinBase.FatalExit (-1); END Crash;
PROCEDURE------------------------------------------------------------- collector --- These procedures provide synchronization primitives for the allocator and collector. This is the Windows/NT version, and depends on the NT thread implementation.GetMemory (size: INTEGER): ADDRESS = (* Return the address of "size" bytes of unused storage *) BEGIN RETURN LOOPHOLE(WinBase.LocalAlloc(WinBase.LMEM_FIXED, size), ADDRESS); END GetMemory;
LockHeap() enters a critical section; the same thread may enter the critical section multiple times. It could be written at user level as:
VAR mutex : MUTEX := NEW(MUTEX); condition: Thread.Condition := NEW(Thread.Condition); thread : Thread.T := NIL; count : CARDINAL := 0;
PROCEDURE LockHeap () = BEGIN LOCK mutex DO IF count = 0 THEN thread := Thread.Self(); INC(count); ELSIF thread = Thread.Self() THEN INC(count); ELSE Thread.Wait(mutex, condition); END; END; END LockHeap;However, it must be possible to call it from anywhere in the collector.
VAR cs: WinBase.LPCRITICAL_SECTION := NIL; csstorage: WinNT.RTL_CRITICAL_SECTION; PROCEDUREUnlockHeap() leaves the critical section. It could be written at user level as:LockHeap () = BEGIN IF (cs = NIL) THEN cs := ADR(csstorage); WinBase.InitializeCriticalSection(cs); END; WinBase.EnterCriticalSection(cs); END LockHeap;
PROCEDURE UnlockHeap () = BEGIN LOCK mutex DO DEC(count); END; IF count = 0 THEN Thread.Signal(condition); END; END UnlockHeap;However, it must be possible to call it from anywhere inside the collector.
PROCEDURE------------------------------------------------------------------- I/O ---UnlockHeap () = BEGIN WinBase.LeaveCriticalSection(cs); END UnlockHeap;
VAR ready := FALSE; stderr : WinDef.HANDLE; (* Perhaps we should explicitly open CONERR$ et al, in case of redirection by parent? *) PROCEDUREWrite (a: ADDRESS; n: INTEGER) = VAR nWritten: INTEGER; BEGIN IF NOT ready THEN EVAL WinCon.AllocConsole(); (* make sure we've got one! *) stderr := WinBase.GetStdHandle(WinBase.STD_ERROR_HANDLE); ready := TRUE; END; EVAL WinBase.WriteFile(stderr, a, n, ADR(nWritten), NIL); END Write; BEGIN END RTOS.