shifting {HEAD ~ the contents} of {TAIL ~ said plurality} of memory locations 2N+1 to 1 to respective ones of memory locations 2N to 0 
of
shifting { HEAD ~ the contents } of { TAIL ~ said plurality } of memory locations 2N+1 to 1 to respective ones of memory locations 2N to 0
OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH