Read-After-Write(RAW) Hazard

Abstract

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• x is only available at t=5, as that’s when the first instruction (x <- y + z) completes. However, the second instruction (w <- x) requires x at t=3. If not handled properly, this discrepancy can lead to incorrect results.

How to handle this?

A RAW (Read After Write) hazard can be addressed with a Pipeline Stall which is a performance hit. Luckily, we can optimise this using Operand Forwarding and Out-of-Order Execution.