Stride Prefetcher

PC: LOAD reg, address

address += stride

Prev. Address

Stride

State

PC Tag

Loop

Reference Prediction Table (RPT)

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To identify such memory references, a hardware stride prefetcher looks at a particular memory instruction over time. If the addresses loaded by this instruction differs by a constant stride, then we have a candidate for stride prefetching.

In hardware, this is accomplished, by maintaining a reference prediction table. This table is index by the PC of memory instructions and it stores the memory address used by the last execution of the memory instruction. A stride can be computed on subsequent executions. A simple state machine is used to identify those memory instructions where the stride does not change over time.