Half-precision sum of outer products to single-precision, accumulating
This instruction works with a 32-bit element ZA tile.
This instruction widens the SVLS×2 sub-matrix of half-precision values held in the first source vector to single-precision values and multiplies it by the widened 2×SVLS sub-matrix of half-precision values in the second source vector to single-precision values.
Each source vector is independently predicated by a corresponding governing predicate. When a 16-bit source element is Inactive it is treated as having the value +0.0, but if both pairs of source vector elements that correspond to a 32-bit destination element contain Inactive elements, then the destination element remains unmodified.
The resulting SVLS×SVLS single-precision sum of outer products is then destructively added to the single-precision destination tile. This is equivalent to performing a 2-way dot product and accumulate to each of the destination tile elements.
Each 32-bit container of the first source vector holds 2 consecutive column elements of each row of a SVLS×2 sub-matrix. Similarly, each 32-bit container of the second source vector holds 2 consecutive row elements of each column of a 2×SVLS sub-matrix.
This instruction follows SME ZA-targeting floating-point behaviors.
| 31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
| 1 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 1 | Zm | Pm | Pn | Zn | 0 | 0 | 0 | ZAda | |||||||||||||
| S | |||||||||||||||||||||||||||||||
if !IsFeatureImplemented(FEAT_SME) then EndOfDecode(Decode_UNDEF); end; let a : integer = UInt(Pn); let b : integer = UInt(Pm); let n : integer = UInt(Zn); let m : integer = UInt(Zm); let da : integer = UInt(ZAda);
| <ZAda> |
Is the name of the ZA tile ZA0-ZA3, encoded in the "ZAda" field. |
| <Pn> |
Is the name of the first governing scalable predicate register P0-P7, encoded in the "Pn" field. |
| <Pm> |
Is the name of the second governing scalable predicate register P0-P7, encoded in the "Pm" 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. |
CheckStreamingSVEAndZAEnabled(); let VL : integer{} = CurrentVL(); let PL : integer{} = VL DIV 8; let dim : integer{} = VL DIV 32; let mask1 : bits(PL) = P{}(a); let mask2 : bits(PL) = P{}(b); let operand1 : bits(VL) = Z{}(n); let operand2 : bits(VL) = Z{}(m); let operand3 : bits(dim*dim*32) = ZAtile{}(da, 32); var result : bits(dim*dim*32); for row = 0 to dim-1 do for col = 0 to dim-1 do // determine row/col predicates let prow_0 : boolean = (ActivePredicateElement{PL}(mask1, 2*row + 0, 16)); let prow_1 : boolean = (ActivePredicateElement{PL}(mask1, 2*row + 1, 16)); let pcol_0 : boolean = (ActivePredicateElement{PL}(mask2, 2*col + 0, 16)); let pcol_1 : boolean = (ActivePredicateElement{PL}(mask2, 2*col + 1, 16)); var sum : bits(32) = operand3[(row*dim+col)*:32]; if (prow_0 && pcol_0) || (prow_1 && pcol_1) then let erow_0 : bits(16) = (if prow_0 then operand1[(2*row + 0)*:16] else FPZero{16}('0')); let erow_1 : bits(16) = (if prow_1 then operand1[(2*row + 1)*:16] else FPZero{16}('0')); let ecol_0 : bits(16) = (if pcol_0 then operand2[(2*col + 0)*:16] else FPZero{16}('0')); let ecol_1 : bits(16) = (if pcol_1 then operand2[(2*col + 1)*:16] else FPZero{16}('0')); sum = FPDotAdd_ZA(sum, erow_0, erow_1, ecol_0, ecol_1, FPCR()); end; result[(row*dim+col)*:32] = sum; end; end; ZAtile{dim*dim*32}(da, 32) = result;
2026-03_rel 2026-03-26 20:48:11
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