A2OS/ARM/Minos/UncachedHeaps.Mos

MODULE UncachedHeap; (** AUTHOR "Timothée Martiel"; PURPOSE "Secondary heap for uncached memory region of bootloader."; *)

IMPORT SYSTEM, Board, Trace;

CONST
	(** Initialize Allocated memory to 0 *)
	Initialize = Board.InitializeUncachedHeap;
VAR
	start, stop, last: ADDRESS;

	(** Returns the beginning address of a reserved memory block of size 'size' *)
	PROCEDURE New * (size: SIZE): ADDRESS;
	VAR
		adr: ADDRESS;
		i: LONGINT;
	BEGIN
		adr := last;
		INC(last, size);
		ASSERT(last < stop);
		ASSERT(start <= last);
		IF Initialize THEN
			FOR i := 0 TO size - 1 DO SYSTEM.PUT8(adr + i, 0) END
		END;
		RETURN adr
	END New;

	(** Free size available on the heap, in bytes. *)
	PROCEDURE Free * (): SIZE;
	BEGIN
		RETURN stop - last
	END Free;

	PROCEDURE Show *;
	BEGIN
		Trace.String("Uncached Heap base = ");
		Trace.Address(start);
		Trace.String("; current = ");
		Trace.Address(last);
		Trace.String("; end = ");
		Trace.Address(stop);
		Trace.Ln
	END Show;
BEGIN
	stop := Board.UncachedHeapEnd;
	start := Board.UncachedHeapBase;
	last := start;
END UncachedHeap.