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. Green True SM_0_only It has encodings from 2 classes: 32-bit element and 64-bit element 1 0 0 0 0 1 0 0 0 0 0 1 1 1 0 PRFB <prfop>, <Pg>, [<Zn>.S{, #<imm>}] 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); 1 1 0 0 0 1 0 0 0 0 0 1 1 1 0 PRFB <prfop>, <Pg>, [<Zn>.D{, #<imm>}] 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); <prfop> Is the prefetch operation specifier, prfop <prfop> 0000 PLDL1KEEP 0001 PLDL1STRM 0010 PLDL2KEEP 0011 PLDL2STRM 0100 PLDL3KEEP 0101 PLDL3STRM x11x #uimm4 1000 PSTL1KEEP 1001 PSTL1STRM 1010 PSTL2KEEP 1011 PSTL2STRM 1100 PSTL3KEEP 1101 PSTL3STRM <Pg> Is the name of the governing scalable predicate register P0-P7, encoded in the "Pg" field. <Zn> Is the name of the base scalable vector register, encoded in the "Zn" field. <imm> Is the optional unsigned immediate byte offset, in the range 0 to 31, defaulting to 0, encoded in the "imm5" field. CheckNonStreamingSVEEnabled(); constant integer VL = CurrentVL; constant integer PL = VL DIV 8; constant integer elements = VL DIV esize; constant bits(PL) mask = P[g, PL]; bits(VL) base; if AnyActiveElement(mask, esize) then base = Z[n, VL]; for e = 0 to elements-1 if ActivePredicateElement(mask, e, esize) then constant bits(64) addr = ZeroExtend(Elem[base, e, esize], 64) + (offset << scale); Hint_Prefetch(addr, pref_hint, level, stream);