SEL (vectors) Conditionally select elements from two vectors Select elements from the first source vector where the corresponding vector select predicate element is true, and from the second source vector where the predicate element is false, placing them in the corresponding elements of the destination vector. Green False True This instruction is used by the alias MOV (vector, predicated) Zd == Zm See below for details of when the alias is preferred. 0 0 0 0 0 1 0 1 1 1 1 SEL <Zd>.<T>, <Pv>, <Zn>.<T>, <Zm>.<T> if !IsFeatureImplemented(FEAT_SVE) && !IsFeatureImplemented(FEAT_SME) then UNDEFINED; constant integer esize = 8 << UInt(size); constant integer v = UInt(Pv); constant integer n = UInt(Zn); constant integer m = UInt(Zm); constant integer d = UInt(Zd); <Zd> Is the name of the destination scalable vector register, encoded in the "Zd" field. <T> Is the size specifier, size <T> 00 B 01 H 10 S 11 D <Pv> Is the name of the vector select predicate register, encoded in the "Pv" field. <Zn> Is the name of the first source scalable vector register, encoded in the "Zn" field. <Zm> Is the name of the second source scalable vector register, encoded in the "Zm" field. Alias Conditions CheckSVEEnabled(); constant integer VL = CurrentVL; constant integer PL = VL DIV 8; constant integer elements = VL DIV esize; constant bits(PL) mask = P[v, PL]; constant bits(VL) operand1 = if AnyActiveElement(mask, esize) then Z[n, VL] else Zeros(VL); constant bits(VL) operand2 = if AnyActiveElement(NOT(mask), esize) then Z[m, VL] else Zeros(VL); bits(VL) result; for e = 0 to elements-1 if ActivePredicateElement(mask, e, esize) then Elem[result, e, esize] = Elem[operand1, e, esize]; else Elem[result, e, esize] = Elem[operand2, e, esize]; Z[d, VL] = result;