{HEAD ~ The mutex registers} can be configured as {TAIL ~ sets} of mutex request registers and mutex release registers 
configured as
{ HEAD ~ The mutex registers } can be configured as { TAIL ~ sets } of mutex request registers and mutex release registers
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH