Hard Processor System Technical Reference Manual: Agilex™ 5 SoCs

ID 814346
Date 7/19/2024
Public

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3.5.3.5.3. Data Prefetching

The Cortex* -A76 core supports the AArch64 Prefetch Memory (PRFM) instructions and the AArch32 Prefetch Data (PLD) and Preload Data with Intent to Write (PLDW) instructions. These instructions signal to the memory system that memory accesses from a specified address are likely to occur soon. The memory system acts by taking actions that aim to reduce the latency of memory access when they occur.

PRFM instructions perform a lookup in the cache, and if they miss and are to a cacheable address, a line fill starts. However, the PRFM instruction retires when its line fill is started, rather than waiting for the line fill to complete. This enables other instructions to execute while the line fill continues in the background.