UMAXP

Unsigned maximum pairwise

Compute the maximum value of each pair of adjacent unsigned integer elements within each source vector, and interleave the results from corresponding lanes. The interleaved result values are destructively placed in the first source vector.

313029282726252423222120191817161514131211109876543210
01000100size010101101PgZmZdn
U

UMAXP <Zdn>.<T>, <Pg>/M, <Zdn>.<T>, <Zm>.<T>

if !HaveSVE2() && !HaveSME() then UNDEFINED; constant integer esize = 8 << UInt(size); integer g = UInt(Pg); integer m = UInt(Zm); integer dn = UInt(Zdn);

Assembler Symbols

<Zdn>

Is the name of the first source and destination scalable vector register, encoded in the "Zdn" field.

<T>

Is the size specifier, encoded in size:

size <T>
00 B
01 H
10 S
11 D
<Pg>

Is the name of the governing scalable predicate register P0-P7, encoded in the "Pg" field.

<Zm>

Is the name of the second source scalable vector register, encoded in the "Zm" field.

Operation

CheckSVEEnabled(); constant integer VL = CurrentVL; constant integer PL = VL DIV 8; constant integer elements = VL DIV esize; bits(PL) mask = P[g, PL]; bits(VL) operand1 = Z[dn, VL]; bits(VL) operand2 = if AnyActiveElement(mask, esize) then Z[m, VL] else Zeros(VL); bits(VL) result; integer element1; integer element2; for e = 0 to elements-1 if !ActivePredicateElement(mask, e, esize) then Elem[result, e, esize] = Elem[operand1, e, esize]; else if IsEven(e) then element1 = UInt(Elem[operand1, e + 0, esize]); element2 = UInt(Elem[operand1, e + 1, esize]); else element1 = UInt(Elem[operand2, e - 1, esize]); element2 = UInt(Elem[operand2, e + 0, esize]); integer res = Max(element1, element2); Elem[result, e, esize] = res<esize-1:0>; Z[dn, VL] = result;

Operational information

If FEAT_SVE2 is implemented or FEAT_SME is implemented, then if PSTATE.DIT is 1:

This instruction might be immediately preceded in program order by a MOVPRFX instruction. The MOVPRFX instruction must conform to all of the following requirements, otherwise the behavior of the MOVPRFX and this instruction is unpredictable:


Internal version only: aarchmrs v2023-12_rel, pseudocode v2023-12_rel, sve v2023-12_rel ; Build timestamp: 2023-12-15T16:46

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