UMLSLB (indexed) Unsigned multiply-subtract long from accumulator (bottom, indexed) Multiply the even-numbered unsigned elements within each 128-bit segment of the first source vector by the specified unsigned element in the corresponding second source vector segment and destructively subtract from the overlapping double-width elements of the addend vector. The elements within the second source vector are specified using an immediate index which selects the same element position within each 128-bit vector segment. The index range is from 0 to one less than the number of elements per 128-bit segment, encoded in 2 or 3 bits depending on the size of the element. Green False True True It has encodings from 2 classes: 32-bit and 64-bit 0 1 0 0 0 1 0 0 1 0 1 1 0 1 1 0 UMLSLB <Zda>.S, <Zn>.H, <Zm>.H[<imm>] if !IsFeatureImplemented(FEAT_SVE2) && !IsFeatureImplemented(FEAT_SME) then UNDEFINED; constant integer esize = 16; constant integer index = UInt(i3h:i3l); constant integer n = UInt(Zn); constant integer m = UInt(Zm); constant integer da = UInt(Zda); constant integer sel = 0; 0 1 0 0 0 1 0 0 1 1 1 1 0 1 1 0 UMLSLB <Zda>.D, <Zn>.S, <Zm>.S[<imm>] if !IsFeatureImplemented(FEAT_SVE2) && !IsFeatureImplemented(FEAT_SME) then UNDEFINED; constant integer esize = 32; constant integer index = UInt(i2h:i2l); constant integer n = UInt(Zn); constant integer m = UInt(Zm); constant integer da = UInt(Zda); constant integer sel = 0; <Zda> Is the name of the third source and destination scalable vector register, encoded in the "Zda" field. <Zn> Is the name of the first source scalable vector register, encoded in the "Zn" field. <Zm> For the 32-bit variant: is the name of the second source scalable vector register Z0-Z7, encoded in the "Zm" field. <Zm> For the 64-bit variant: is the name of the second source scalable vector register Z0-Z15, encoded in the "Zm" field. <imm> For the 32-bit variant: is the element index, in the range 0 to 7, encoded in the "i3h:i3l" fields. <imm> For the 64-bit variant: is the element index, in the range 0 to 3, encoded in the "i2h:i2l" fields. CheckSVEEnabled(); constant integer VL = CurrentVL; constant integer PL = VL DIV 8; constant integer elements = VL DIV (2 * esize); constant integer eltspersegment = 128 DIV (2 * esize); constant bits(VL) operand1 = Z[n, VL]; constant bits(VL) operand2 = Z[m, VL]; bits(VL) result = Z[da, VL]; for e = 0 to elements-1 constant integer s = e - (e MOD eltspersegment); constant integer element1 = UInt(Elem[operand1, 2 * e + sel, esize]); constant integer element2 = UInt(Elem[operand2, 2 * s + index, esize]); constant bits(2*esize) product = (element1 * element2)<2*esize-1:0>; Elem[result, e, 2*esize] = Elem[result, e, 2*esize] - product; Z[da, VL] = result;