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