_REG_PCSQH
uc.uc_mcontext.__gregs[_REG_PCSQH] = sc->sc_pcsqh;
if (gr[_REG_PCSQH] != pmap_sid(pmap, gr[_REG_PCOQH])) {
gr[_REG_PCSQH] = tf->tf_iisq_head;