DECP (scalar)

Decrement scalar by active predicate element count.

Counts the number of active elements in the source predicate and then uses the result to decrement the scalar destination.

313029282726252423222120191817161514131211109876543210
00100101size1011011000100PgRdn

SVE

DECP <Xdn>, <Pg>.<T>

if !HaveSVE() then UNDEFINED; integer esize = 8 << UInt(size); integer g = UInt(Pg); integer dn = UInt(Rdn);

Assembler Symbols

<Xdn>

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

<Pg>

Is the name of the governing scalable predicate register, encoded in the "Pg" field.

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

Operation

CheckSVEEnabled(); integer elements = VL DIV esize; bits(PL) mask = P[g]; bits(64) operand = X[dn]; integer count = 0; for e = 0 to elements-1 if ElemP[mask, e, esize] == '1' then count = count + 1; X[dn] = operand - count;


Release: 00rel5-manual

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