INT 2F - DOS 5+ - ALLOCATE HMAsee High Memory Area SPACE
	AX = 4A02h
	BX = number of bytes
Return: ES:DI -> start of allocated HMAsee High Memory Area block or FFFFh:FFFFh
	BX = number of bytes actually allocated (rounded up to next paragraph
	      for DOS 5.0 and 6.0)
Notes:	this call is not valid unless DOS is loaded in the HMAsee High Memory Area (DOS=HIGH)
	called by Windows 3.1 DOSX.EXE
	supported by Novell DOS 7
SeeAlso: AX=4A01h,AX=4A03h