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SQDECP (vector)

Signed saturating decrement vector by countactive ofpredicate trueelement predicate elements.count.

Counts the number of trueactive elements in the source predicate and then uses the result to decrement all destination vector elements. The results are saturated to the element signed integer range.

The predicate size specifier may be omitted in assembler source code, but this is deprecated and will be prohibited in a future release of the architecture.

313029282726252423222120191817161514131211109876543210
00100101size1010101000000PmPgZdn

SVE

SQDECP <Zdn>.<T>, <Pm><Pg>.<T>

if !HaveSVE() then UNDEFINED; if size == '00' then UNDEFINED; integer esize = 8 << UInt(size); integer m =integer g = UInt(Pm); (Pg); integer dn = UInt(Zdn); boolean unsigned = FALSE;

Assembler Symbols

<Zdn>

Is the name of the source and destination scalable vector register, encoded in the "Zdn" field.

<T> Is the size specifier, encoded in size:
size<T>
00RESERVED
01H
10S
11D
<PmPg>

Is the name of the sourcegoverning scalable predicate register, encoded in the "PmPg" field.

Operation

CheckSVEEnabled(); integer elements = VL DIV esize; bits(VL) operand1 =bits(PL) mask = P[g]; bits(VL) operand = Z[dn]; bits(PL) operand2 = P[m]; [dn]; bits(VL) result; integer count = 0; for e = 0 to elements-1 if ElemP[operand2, e, esize] == '1' then [mask, e, esize] == '1' then count = count + 1; for e = 0 to elements-1 integer element = Int(Elem[operand1, e, esize], unsigned); [operand, e, esize], unsigned); (Elem[result, e, esize], -) = SatQ(element - count, esize, unsigned); Z[dn] = result;

Operational information

If PSTATE.DIT is 1:

This instruction might be immediately preceded in program order by a MOVPRFX instruction that conforms to all of the following requirements, otherwise the behavior of either or both instructions is unpredictable:

The MOVPRFX instructions that can be used with this instruction are as follows:


Internal version only: isa v30.44v30.42, AdvSIMD v27.08, pseudocode v8.5-2019-06_rc2-5-g22901f2future-20190403, sve v2019-06_rc4v8.5-00bet10_rc5 ; Build timestamp: 2019-06-26T222019-04-17T09:0458

Copyright © 2010-2019 Arm Limited or its affiliates. All rights reserved. This document is Non-Confidential.

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