CHKFEAT Check feature status This instruction indicates the status of features. If FEAT_CHK is not implemented, this instruction executes as a NOP. 1 1 0 1 0 1 0 1 0 0 0 0 0 0 1 1 0 0 1 0 0 1 0 1 0 0 0 1 1 1 1 1 CHKFEAT X16 if !IsFeatureImplemented(FEAT_CHK) then ExecuteAsNOP(); X[16, 64] = AArch64.ChkFeat(X[16, 64]);