Add with carry long (top)
This instruction adds the odd-numbered elements of the first source vector and the 1-bit carry from the least-significant bit of the odd-numbered elements of the second source vector to the even-numbered elements of the destination and accumulator vector. The 1-bit carry output is placed in the corresponding odd-numbered element of the destination vector.
| 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 |
| 0 | 1 | 0 | 0 | 0 | 1 | 0 | 1 | 0 | sz | 0 | Zm | 1 | 1 | 0 | 1 | 0 | 1 | Zn | Zda | ||||||||||||
| T | |||||||||||||||||||||||||||||||
if !IsFeatureImplemented(FEAT_SVE2) && !IsFeatureImplemented(FEAT_SME) then EndOfDecode(Decode_UNDEF); end; let esize : integer{} = 32 << UInt(sz); let n : integer = UInt(Zn); let m : integer = UInt(Zm); let da : integer = UInt(Zda);
| <Zda> |
Is the name of the third source and destination scalable vector register, encoded in the "Zda" field. |
| <T> |
Is the size specifier,
encoded in
|
| <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. |
CheckSVEEnabled(); let VL : integer{} = CurrentVL(); let pairs : integer = VL DIV (esize * 2); let operand : bits(VL) = Z{}(n); let carries : bits(VL) = Z{}(m); var result : bits(VL) = Z{}(da); for p = 0 to pairs-1 do let element1 : bits(esize) = result[(2*p + 0)*:esize]; let element2 : bits(esize) = operand[(2*p + 1)*:esize]; let carry_in : bit = carries[(2*p + 1)*:esize][0]; let (res, nzcv) = AddWithCarry{esize}(element1, element2, carry_in); let carry_out : bit = nzcv[1]; result[(2*p + 0)*:esize] = res; result[(2*p + 1)*:esize] = ZeroExtend{esize}(carry_out); end; Z{VL}(da) = result;
This instruction is a data-independent-time instruction as described in About PSTATE.DIT.
This instruction might be immediately preceded in program order by a MOVPRFX instruction. The MOVPRFX must conform to all of the following requirements, otherwise the behavior of the MOVPRFX and this instruction is CONSTRAINED UNPREDICTABLE:
2025-09_diff_tag 2025-11-28 16:29:05
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