SB Speculation barrier This instruction is a barrier that controls speculation. For more information and details of the semantics, see Speculation Barrier (SB). 1 1 0 1 0 1 0 1 0 0 0 0 0 0 1 1 0 0 1 1 (0) (0) (0) (0) 1 1 1 1 1 1 1 1 SB if !IsFeatureImplemented(FEAT_SB) then EndOfDecode(Decode_UNDEF); end; SpeculationBarrier(); 2026-03-26 20:27:25 2026-03_rel