{HEAD ~ Each stage} begins with {TAIL ~ four 32 bit values} in an A register, a B register; a C register; and a D register 
begins with
{ HEAD ~ Each stage } begins with { TAIL ~ four 32 bit values } in an A register , a B register ; a C register ; and a D register
HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH