Initialize predicate from named constraint
This instruction sets elements of the destination predicate to true if the element number satisfies the named predicate constraint, or to false otherwise. If the constraint specifies more elements than are available at the current vector length, then all elements of the destination predicate are set to false.
The named predicate constraint limits the number of active elements in a single predicate to:
Unspecified or out of range constraint encodings generate an empty predicate or zero element count rather than Undefined Instruction exception. This instruction does not set the condition flags.
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| 0 | 0 | 1 | 0 | 0 | 1 | 0 | 1 | size | 0 | 1 | 1 | 0 | 0 | 0 | 1 | 1 | 1 | 0 | 0 | 0 | pattern | 0 | Pd | ||||||||
| S | |||||||||||||||||||||||||||||||
if !IsFeatureImplemented(FEAT_SVE) && !IsFeatureImplemented(FEAT_SME) then EndOfDecode(Decode_UNDEF); end; let esize : integer{} = 8 << UInt(size); let d : integer = UInt(Pd); let setflags : boolean = FALSE; let pat : bits(5) = pattern;
| <Pd> |
Is the name of the destination scalable predicate register, encoded in the "Pd" field. |
| <T> |
Is the size specifier,
encoded in
|
CheckSVEEnabled(); let VL : integer{} = CurrentVL(); let PL : integer{} = VL DIV 8; let elements : integer = VL DIV esize; let count : integer = DecodePredCount(pat, esize); var result : bits(PL); let psize : integer{} = esize DIV 8; for e = 0 to elements-1 do let pbit : bit = if e < count then '1' else '0'; result[e*:psize] = ZeroExtend{psize}(pbit); end; if setflags then PSTATE.[N,Z,C,V] = PredTest{PL}(result, result, esize); end; P{PL}(d) = result;
2026-03_rel 2026-03-26 20:48:11
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