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PTEST

Set condition flags for predicate.

Sets the First (N), None (Z), !Last (C) condition flags based on the predicate source register, and the V flag to zero.

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001001010101000011Pg0Pn00000
S

PTEST <Pg>, <Pn>.B

if !HaveSVE() then UNDEFINED;
integer esize = 8;
integer g = UInt(Pg);
integer n = UInt(Pn);

Assembler Symbols

<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();
bits(PL) mask = P[g];
bits(PL) result = P[n];

PSTATE.<N,Z,C,V> = PredTest(mask, result, esize);

Operational information

If PSTATE.DIT is 1:

  • The execution time of this instruction is independent of:
    • The values of the data supplied in any of its operand registers when its governing predicate register contains the same value for each execution.
    • The values of the NZCV flags.
  • The response of this instruction to asynchronous exceptions does not vary based on:
    • The values of the data supplied in any of its operand registers when its governing predicate register contains the same value for each execution.
    • The values of the NZCV flags.