Sequence of events

• Issue: as before except ROB register is allocated and passed tag of the FU which will generate the result.

  Branches are also passed to the ROB

• Execute: no change
• Write result: broadcast on CDB as before, but result is collected in ROB register instead of true register
• Commit: ROB register is allocated for each uncommitted inst$^{\rm n}$. Process them in order, writing results to true destination

Note

• true registers are only updated by ROB