USDOT (indexed) Unsigned by signed integer indexed dot product The unsigned by signed integer indexed dot product instruction computes the dot product of a group of four unsigned 8-bit integer values held in each 32-bit element of the first source vector multiplied by a group of four signed 8-bit integer values in an indexed 32-bit element of the second source vector, and then destructively adds the widened dot product to the corresponding 32-bit element of the destination vector. The groups within the second source vector are specified using an immediate index which selects the same group position within each 128-bit vector segment. The index range is from 0 to 3. This instruction is unpredicated. ID_AA64ZFR0_EL1.I8MM indicates whether this instruction is implemented. Green False True True 0 1 0 0 0 1 0 0 1 0 1 0 0 0 1 1 0 USDOT <Zda>.S, <Zn>.B, <Zm>.B[<imm>] if ((!IsFeatureImplemented(FEAT_SVE) && !IsFeatureImplemented(FEAT_SME)) || !IsFeatureImplemented(FEAT_I8MM)) then UNDEFINED; constant integer esize = 32; constant integer index = UInt(i2); constant integer n = UInt(Zn); constant integer m = UInt(Zm); constant integer da = UInt(Zda); <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> Is the name of the second source scalable vector register Z0-Z7, encoded in the "Zm" field. <imm> Is the immediate index of a 32-bit group of four 8-bit values within each 128-bit vector segment, in the range 0 to 3, encoded in the "i2" field. CheckSVEEnabled(); constant integer VL = CurrentVL; constant integer PL = VL DIV 8; constant integer elements = VL DIV esize; constant integer eltspersegment = 128 DIV esize; constant bits(VL) operand1 = Z[n, VL]; constant bits(VL) operand2 = Z[m, VL]; constant bits(VL) operand3 = Z[da, VL]; bits(VL) result; for e = 0 to elements-1 constant integer segmentbase = e - (e MOD eltspersegment); constant integer s = segmentbase + index; bits(esize) res = Elem[operand3, e, esize]; for i = 0 to 3 constant integer element1 = UInt(Elem[operand1, 4 * e + i, esize DIV 4]); constant integer element2 = SInt(Elem[operand2, 4 * s + i, esize DIV 4]); res = res + element1 * element2; Elem[result, e, esize] = res; Z[da, VL] = result;