Signed multiply long by indexed element (top)
This instruction multiplies the odd-numbered signed elements within each 128-bit segment of the first source vector by the specified element in the corresponding second source vector segment, and places the results in the overlapping double-width elements of the destination vector register.
The elements within the second source vector are specified using an immediate index that selects the same element position within each 128-bit vector segment. The index range is from 0 to one less than the number of elements per 128-bit segment.
It has encodings from 2 classes: 32-bit and 64-bit
| 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 | 0 | 1 | 0 | 1 | i3h | Zm | 1 | 1 | 0 | 0 | i3l | 1 | Zn | Zd | |||||||||||
| size | U | T | |||||||||||||||||||||||||||||
if !IsFeatureImplemented(FEAT_SVE2) && !IsFeatureImplemented(FEAT_SME) then EndOfDecode(Decode_UNDEF); end; let esize : integer{} = 16; let index : integer = UInt(i3h::i3l); let n : integer = UInt(Zn); let m : integer = UInt(Zm); let d : integer = UInt(Zd); let sel : integer = 1;
| 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 | 0 | 1 | 1 | 1 | i2h | Zm | 1 | 1 | 0 | 0 | i2l | 1 | Zn | Zd | |||||||||||
| size | U | T | |||||||||||||||||||||||||||||
if !IsFeatureImplemented(FEAT_SVE2) && !IsFeatureImplemented(FEAT_SME) then EndOfDecode(Decode_UNDEF); end; let esize : integer{} = 32; let index : integer = UInt(i2h::i2l); let n : integer = UInt(Zn); let m : integer = UInt(Zm); let d : integer = UInt(Zd); let sel : integer = 1;
| <Zd> |
Is the name of the destination scalable vector register, encoded in the "Zd" field. |
| <Zn> |
Is the name of the first source scalable vector register, encoded in the "Zn" field. |
CheckSVEEnabled(); let VL : integer{} = CurrentVL(); let elements : integer = VL DIV (2 * esize); let eltspersegment : integer = 128 DIV (2 * 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 s : integer = e - (e MOD eltspersegment); let element1 : integer = SInt(operand1[(2 * e + sel)*:esize]); let element2 : integer = SInt(operand2[(2 * s + index)*:esize]); let res : integer = element1 * element2; result[e*:(2*esize)] = res[2*esize-1:0]; end; Z{VL}(d) = result;
This instruction is a data-independent-time instruction as described in About PSTATE.DIT.
2026-03_rel 2026-03-26 20:48:11
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