CNTP (predicate as counter)

Set scalar to count from predicate-as-counter

Counts the number of true elements in the source predicate and places the scalar result in the destination general-purpose register.

SVE2
(FEAT_SVE2p1)

313029282726252423222120191817161514131211109876543210
00100101size10000010000vl1PNnRd

CNTP <Xd>, <PNn>.<T>, <vl>

if !IsFeatureImplemented(FEAT_SME2) && !IsFeatureImplemented(FEAT_SVE2p1) then UNDEFINED; constant integer esize = 8 << UInt(size); constant integer n = UInt(PNn); constant integer d = UInt(Rd); constant integer width = 2 << UInt(vl);

Assembler Symbols

<Xd>

Is the 64-bit name of the destination general-purpose register, encoded in the "Rd" field.

<PNn>

Is the name of the first source scalable predicate register, with predicate-as-counter encoding, encoded in the "PNn" field.

<T>

Is the size specifier, encoded in size:

size <T>
00 B
01 H
10 S
11 D
<vl>

Is the vl specifier, encoded in vl:

vl <vl>
0 VLx2
1 VLx4

Operation

if IsFeatureImplemented(FEAT_SVE2p1) then CheckSVEEnabled(); else CheckStreamingSVEEnabled(); constant integer VL = CurrentVL; constant integer PL = VL DIV 8; constant integer elements = VL DIV esize; constant bits(PL) pred = P[n, PL]; constant bits(PL*4) mask = CounterToPredicate(pred<15:0>, PL*4); bits(64) sum = Zeros(64); constant integer limit = elements * width; for e = 0 to limit-1 if ActivePredicateElement(mask, e, esize) then sum = sum + 1; X[d, 64] = sum;

Operational information

If PSTATE.DIT is 1:


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

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