INT 31 - CauseWay - "GetMem" - ALLOCATE BLOCK OF MEMORY

	AX = FF0Bh
	CX:DX = size in bytes (FFFFh:FFFFh to get size of largest available)
Return: CF clear if successful
	    BX = selector for accessing block if requested size not FFFFh:FFFFh
	    CX:DX = size of largest available block if requested FFFFh:FFFFh
	CF set on error
SeeAlso: AX=FF0Ch,AX=FF0Dh,AX=FF0Fh,AX=FF10h,AX=FF2Ch