PRFH (scalar plus immediate)

Contiguous prefetch halfwords (immediate index)

Contiguous prefetch of halfword elements from the memory address generated by a 64-bit scalar base and immediate index in the range -32 to 31 which is multiplied by the vector's in-memory size, irrespective of predication, and added to the base address.

The predicate may be used to suppress prefetches from unwanted addresses.

313029282726252423222120191817161514131211109876543210
1000010111imm6001PgRn0prfop
msz<1>msz<0>

PRFH <prfop>, <Pg>, [<Xn|SP>{, #<imm>, MUL VL}]

if !IsFeatureImplemented(FEAT_SVE) && !IsFeatureImplemented(FEAT_SME) then UNDEFINED; constant integer esize = 16; constant integer g = UInt(Pg); constant integer n = UInt(Rn); 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 = 1; constant integer offset = SInt(imm6);

Assembler Symbols

<prfop>

Is the prefetch operation specifier, encoded in prfop:

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.

<Xn|SP>

Is the 64-bit name of the general-purpose base register or stack pointer, encoded in the "Rn" field.

<imm>

Is the optional signed immediate vector offset, in the range -32 to 31, defaulting to 0, encoded in the "imm6" field.

Operation

CheckSVEEnabled(); constant integer VL = CurrentVL; constant integer PL = VL DIV 8; constant integer elements = VL DIV esize; constant bits(PL) mask = P[g, PL]; bits(64) base; if AnyActiveElement(mask, esize) then base = if n == 31 then SP[] else X[n, 64]; for e = 0 to elements-1 if ActivePredicateElement(mask, e, esize) then constant integer eoff = (offset * elements) + e; constant bits(64) addr = base + (eoff << scale); Hint_Prefetch(addr, pref_hint, level, stream);


Internal version only: aarchmrs v2024-03_relA, pseudocode v2024-03_rel, sve v2024-03_rel ; Build timestamp: 2024-03-26T09:45

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