Bitwise exclusive NOR population count outer product, subtracting
This instruction works with 32-bit element ZA tile. This instruction generates an outer product of the first source SVLS×1 vector and the second source 1×SVLS vector. Each outer product element is obtained as population count of the bitwise XNOR result of the corresponding 32-bit elements of the first source vector and the second source vector. Each source vector is independently predicated by a corresponding governing predicate. When either source vector element is inactive the corresponding destination tile element remains unmodified. The resulting SVLS×SVLS product is then destructively subtracted from the destination tile.
| 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 | 0 | 1 | 0 | 0 | Zm | Pm | Pn | Zn | 1 | 1 | 0 | ZAda | |||||||||||||
| S | |||||||||||||||||||||||||||||||
if !IsFeatureImplemented(FEAT_SME2) then EndOfDecode(Decode_UNDEF); end; let esize : integer{} = 32; 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 esize; 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*esize) = ZAtile{}(da, esize); var result : bits(dim*dim*esize); for row = 0 to dim-1 do let element1 : bits(esize) = operand1[row*:esize]; for col = 0 to dim-1 do let element2 : bits(esize) = operand2[col*:esize]; let element3 : bits(esize) = operand3[(row*dim + col)*:esize]; if (ActivePredicateElement{PL}(mask1, row, esize) && ActivePredicateElement{PL}(mask2, col, esize)) then let res : integer = BitCount(NOT(element1 XOR element2)); result[(row*dim + col)*:esize] = element3 - res; else result[(row*dim + col)*:esize] = element3; end; end; end; ZAtile{dim*dim*esize}(da, esize) = result;
This instruction is a data-independent-time instruction as described in About PSTATE.DIT.
2025-12_rel 2025-12-10 16:41:45
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