Speculation Barrier is a barrier that controls speculation. For more information and details of the semantics, see Speculation Barrier (SB).
| 31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
| 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 |
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if !IsFeatureImplemented(FEAT_SB) then UNDEFINED;