BRKAS

Break after first true condition, setting the condition flags

Sets destination predicate elements up to and including the first active and true source element to true, then sets subsequent elements to false. Inactive elements in the destination predicate register are set to zero. Sets the First (N), None (Z), !Last (C) condition flags based on the predicate result, and the V flag to zero.

313029282726252423222120191817161514131211109876543210
001001010101000001Pg0Pn0Pd
BSM

BRKAS <Pd>.B, <Pg>/Z, <Pn>.B

if !IsFeatureImplemented(FEAT_SVE) && !IsFeatureImplemented(FEAT_SME) then UNDEFINED; constant integer esize = 8; constant integer g = UInt(Pg); constant integer n = UInt(Pn); constant integer d = UInt(Pd); constant boolean merging = FALSE; constant boolean setflags = TRUE;

Assembler Symbols

<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 source scalable predicate register, encoded in the "Pn" field.

Operation

CheckSVEEnabled(); constant integer VL = CurrentVL; constant integer PL = VL DIV 8; constant integer elements = VL DIV esize; constant bits(PL) mask = P[g, PL]; constant bits(PL) operand = P[n, PL]; constant bits(PL) operand2 = P[d, PL]; boolean break = FALSE; bits(PL) result; constant integer psize = esize DIV 8; for e = 0 to elements-1 constant boolean element = ActivePredicateElement(operand, e, esize); if ActivePredicateElement(mask, e, esize) then constant bit pbit = if !break then '1' else '0'; Elem[result, e, psize] = ZeroExtend(pbit, psize); break = break || element; elsif merging then constant bit pbit = PredicateElement(operand2, e, esize); Elem[result, e, psize] = ZeroExtend(pbit, psize); else Elem[result, e, psize] = ZeroExtend('0', psize); if setflags then PSTATE.<N,Z,C,V> = PredTest(mask, result, esize); P[d, PL] = result;

Operational information

If FEAT_SME is implemented and the PE is in Streaming SVE mode, then any subsequent instruction which is dependent on the NZCV condition flags written by this instruction might be significantly delayed.


Internal version only: aarchmrs v2024-03_relA, pseudocode v2024-03_rel, sve v2024-03_rel ; Build timestamp: 2024-03-26T09:45

Copyright © 2010-2024 Arm Limited or its affiliates. All rights reserved. This document is Non-Confidential.