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PUNPKHI, PUNPKLO

Unpack and widen half of predicate

This instruction unpacks elements from the lowest or highest half of the source predicate and places them in elements of twice their size within the destination predicate. This instruction is unpredicated.

It has encodings from 2 classes: High half and Low half

High half class

(FEAT_SVE || FEAT_SME)

313029282726252423222120191817161514131211109876543210
00000101001100010100000Pn0Pd
H

Encoding

PUNPKHI <Pd>.H, <Pn>.B

Decode

if !IsFeatureImplemented(FEAT_SVE) && !IsFeatureImplemented(FEAT_SME) then EndOfDecode(Decode_UNDEF); constant integer esize = 16; constant integer n = UInt(Pn); constant integer d = UInt(Pd); constant boolean hi = TRUE;

Low half class

(FEAT_SVE || FEAT_SME)

313029282726252423222120191817161514131211109876543210
00000101001100000100000Pn0Pd
H

Encoding

PUNPKLO <Pd>.H, <Pn>.B

Decode

if !IsFeatureImplemented(FEAT_SVE) && !IsFeatureImplemented(FEAT_SME) then EndOfDecode(Decode_UNDEF); constant integer esize = 16; constant integer n = UInt(Pn); constant integer d = UInt(Pd); constant boolean hi = FALSE;

Assembler Symbols

<Pd>

Is the name of the destination scalable predicate register, encoded in the "Pd" field.

<Pn>

Is the name of the source scalable predicate register, encoded in the "Pn" field.

Operation

CheckSVEEnabled(); constant integer VL = CurrentVL; constant integer PL = VL DIV 8; constant integer elements = VL DIV esize; constant bits(PL) operand = P[n, PL]; bits(PL) result; constant integer psize = esize DIV 8; for e = 0 to elements-1 constant bit pbit = PredicateElement(operand, if hi then e + elements else e, esize DIV 2); Elem[result, e, psize] = ZeroExtend(pbit, psize); P[d, PL] = result;

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