CPUs and architecture

In an out-of-order CPU, which mechanism commits (retires) the results of instructions executed out of order in the program's original order?

  1. AReorder buffer
  2. BSnoop filter
  3. CTLB
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Answer: A. Reorder buffer

The reorder buffer temporarily holds the results of instructions executed out of order and commits them in program order. When an exception or branch misprediction occurs, results of later instructions can be discarded to restore the correct state (precise exceptions).

  • A. Correct. It commits results in the original order.
  • B. A snoop filter reduces cache-coherence traffic.
  • C. The TLB is a cache for address translations.
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