Signed saturating rounding doubling multiply high (unpredicated)
This instruction multiplies the signed elements of the first source vector by the corresponding signed elements of the second source vector, and then doubles the result and places the most significant rounded half of the result in the corresponding elements of the destination vector. Each result element is saturated to the N-bit element's signed integer range -2(N-1) to (2(N-1))-1. This instruction is unpredicated.
| 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 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | size | 1 | Zm | 0 | 1 | 1 | 1 | 0 | 1 | Zn | Zd | |||||||||||||
| R | |||||||||||||||||||||||||||||||
if !IsFeatureImplemented(FEAT_SVE2) && !IsFeatureImplemented(FEAT_SME) then EndOfDecode(Decode_UNDEF); end; let esize : integer{} = 8 << UInt(size); let n : integer = UInt(Zn); let m : integer = UInt(Zm); let d : integer = UInt(Zd);
| <Zd> |
Is the name of the destination scalable vector register, encoded in the "Zd" 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 elements : integer = VL DIV esize; let operand1 : bits(VL) = Z{}(n); let operand2 : bits(VL) = Z{}(m); var result : bits(VL); for e = 0 to elements-1 do let element1 : integer = SInt(operand1[e*:esize]); let element2 : integer = SInt(operand2[e*:esize]); let res : integer = 2 * element1 * element2; result[e*:esize] = SignedSat{esize}((res + (1 << (esize - 1))) >> esize); end; Z{VL}(d) = 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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