Conditionally select elements from two predicates
This instruction reads Active elements from the first source predicate and Inactive elements from the second source predicate and places them in the corresponding elements of the destination predicate. This instruction does not set the condition flags.
This instruction is used by the alias MOV (predicate, merging).
| 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 | 1 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | 0 | 0 | Pm | 0 | 1 | Pg | 1 | Pn | 1 | Pd | ||||||||||||
| op | S | o2 | o3 | ||||||||||||||||||||||||||||
if !IsFeatureImplemented(FEAT_SVE) && !IsFeatureImplemented(FEAT_SME) then EndOfDecode(Decode_UNDEF); end; let esize : integer{} = 8; let g : integer = UInt(Pg); let n : integer = UInt(Pn); let m : integer = UInt(Pm); let d : integer = UInt(Pd);
| <Pd> |
Is the name of the destination scalable predicate register, encoded in the "Pd" field. |
| <Pg> |
Is the name of the governing scalable predicate register, encoded in the "Pg" field. |
| <Pn> |
Is the name of the first source scalable predicate register, encoded in the "Pn" field. |
| <Pm> |
Is the name of the second source scalable predicate register, encoded in the "Pm" field. |
| Alias | Is preferred when |
|---|---|
| MOV (predicate, merging) | Pd == Pm |
CheckSVEEnabled(); let VL : integer{} = CurrentVL(); let PL : integer{} = VL DIV 8; let elements : integer = VL DIV esize; let mask : bits(PL) = P{}(g); let operand1 : bits(PL) = P{}(n); let operand2 : bits(PL) = P{}(m); var result : bits(PL); let psize : integer{} = esize DIV 8; for e = 0 to elements-1 do let element1 : bit = PredicateElement{PL}(operand1, e, esize); let element2 : bit = PredicateElement{PL}(operand2, e, esize); if ActivePredicateElement{PL}(mask, e, esize) then result[e*:psize] = ZeroExtend{psize}(element1); else result[e*:psize] = ZeroExtend{psize}(element2); end; end; P{PL}(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
Copyright © 2010-2026 Arm Limited or its affiliates. All rights reserved. This document is Non-Confidential.