UHSUB Unsigned halving subtract Subtract active unsigned elements of the second source vector from corresponding unsigned elements of the first source vector, shift right one bit, and destructively place the results in the corresponding elements of the first source vector. Inactive elements in the destination vector register remain unmodified. Green True True True True 0 1 0 0 0 1 0 0 0 1 0 0 1 1 1 0 0 UHSUB <Zdn>.<T>, <Pg>/M, <Zdn>.<T>, <Zm>.<T> if !IsFeatureImplemented(FEAT_SVE2) && !IsFeatureImplemented(FEAT_SME) then UNDEFINED; constant integer esize = 8 << UInt(size); constant integer g = UInt(Pg); constant integer dn = UInt(Zdn); constant integer m = UInt(Zm); <Zdn> Is the name of the first source and destination scalable vector register, encoded in the "Zdn" field. <T> Is the size specifier, 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.
CheckSVEEnabled(); constant integer VL = CurrentVL; constant integer PL = VL DIV 8; constant integer elements = VL DIV esize; constant bits(PL) mask = P[g, PL]; constant bits(VL) operand1 = Z[dn, VL]; constant bits(VL) operand2 = if AnyActiveElement(mask, esize) then Z[m, VL] else Zeros(VL); bits(VL) result; for e = 0 to elements-1 constant integer element1 = UInt(Elem[operand1, e, esize]); constant integer element2 = UInt(Elem[operand2, e, esize]); if ActivePredicateElement(mask, e, esize) then constant integer res = (element1 - element2) >> 1; Elem[result, e, esize] = res<esize-1:0>; else Elem[result, e, esize] = Elem[operand1, e, esize]; Z[dn, VL] = result;