_REG_PCSQT
uc.uc_mcontext.__gregs[_REG_PCSQT] = sc->sc_pcsqt;
gr[_REG_PCSQT] = tf->tf_iisq_tail;
if (gr[_REG_PCSQT] != pmap_sid(pmap, gr[_REG_PCOQT])) {