Signed maximum reduction of quadword vector segments
This instruction determines the signed maximum of the elements in the same position from each 128-bit source vector segment, and places each result into the corresponding element of the 128-bit SIMD&FP destination register. Inactive elements in the source vector are treated as the minimum signed integer for the element size.
| 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 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 1 | Pg | Zn | Vd | |||||||||||
| op | U | ||||||||||||||||||||||||||||||
if !IsFeatureImplemented(FEAT_SVE2p1) && !IsFeatureImplemented(FEAT_SME2p1) then EndOfDecode(Decode_UNDEF); end; let esize : integer{} = 8 << UInt(size); let g : integer = UInt(Pg); let n : integer = UInt(Zn); let d : integer = UInt(Vd); let unsigned : boolean = FALSE;
| <Vd> |
Is the name of the destination SIMD&FP register, encoded in the "Vd" field. |
| <T> |
Is an arrangement specifier,
encoded in
|
| <Pg> |
Is the name of the governing scalable predicate register P0-P7, encoded in the "Pg" field. |
| <Zn> |
Is the name of the source scalable vector register, encoded in the "Zn" field. |
| <Tb> |
Is the size specifier,
encoded in
|
CheckSVEEnabled(); let VL : integer{} = CurrentVL(); let PL : integer{} = VL DIV 8; let segments : integer = VL DIV 128; let elempersegment : integer = 128 DIV esize; let mask : bits(PL) = P{}(g); let operand : bits(VL) = if AnyActiveElement{PL}(mask, esize) then Z{VL}(n) else Zeros{VL}; var result : bits(128) = Zeros{}; var stmp : bits(128) = Zeros{}; var dtmp : integer; for e = 0 to elempersegment-1 do dtmp = if unsigned then 0 else -(2^(esize-1)); for s = 0 to segments-1 do if ActivePredicateElement{PL}(mask, s * elempersegment + e, esize) then stmp = operand[s*:128]; dtmp = Max(dtmp, SInt(stmp[e*:esize])); end; end; result[e*:esize] = dtmp[esize-1:0]; end; V{128}(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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