PRFB (vector plus immediate)

Gather prefetch bytes (vector plus immediate)

Gather prefetch of bytes from the active memory addresses generated by a vector base plus immediate index. The index is in the range 0 to 31. Inactive addresses are not prefetched from memory.

The <prfop> symbol specifies the prefetch hint as a combination of three options: access type PLD for load or PST for store; target cache level L1, L2 or L3; temporality (KEEP for temporal or STRM for non-temporal).

This instruction is illegal when executed in Streaming SVE mode, unless FEAT_SME_FA64 is implemented and enabled.

It has encodings from 2 classes: 32-bit element and 64-bit element

32-bit element

if !IsFeatureImplemented(FEAT_SVE) then UNDEFINED; constant integer esize = 32; constant integer g = UInt(Pg); constant integer n = UInt(Zn); constant integer level = UInt(prfop<2:1>); constant boolean stream = (prfop<0> == '1'); constant PrefetchHint pref_hint = if prfop<3> == '0' then Prefetch_READ else Prefetch_WRITE; constant integer scale = 0; constant integer offset = UInt(imm5);

64-bit element

if !IsFeatureImplemented(FEAT_SVE) then UNDEFINED; constant integer esize = 64; constant integer g = UInt(Pg); constant integer n = UInt(Zn); constant integer level = UInt(prfop<2:1>); constant boolean stream = (prfop<0> == '1'); constant PrefetchHint pref_hint = if prfop<3> == '0' then Prefetch_READ else Prefetch_WRITE; constant integer scale = 0; constant integer offset = UInt(imm5);