{HEAD ~ An IOM} tracks the order of instruction execution through the pipeline—that is, which instructions are older or newer than a given instruction—by maintaining representations of {TAIL ~ instructions} in true program order, such as in a circular buffer, FIFO, or the like 
{ HEAD ~ An IOM } tracks the order of instruction execution through the pipeline — that is , which instructions are older or newer than a given instruction — by maintaining representations of { TAIL ~ instructions } in true program order , such as in a circular buffer , FIFO , or the like
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH