BTBC_ENABLED
if (sc->sc_flags & BTBC_ENABLED)
sc->sc_flags |= BTBC_ENABLED;
if ((sc->sc_flags & BTBC_ENABLED) == 0)
sc->sc_flags &= ~BTBC_ENABLED;
KASSERT(sc->sc_flags & BTBC_ENABLED);
KASSERT(sc->sc_flags & BTBC_ENABLED);
KASSERT(sc->sc_flags & BTBC_ENABLED);