sr_mpp
*(srp->sr_mpp) = mp;
srp->sr_mpp = &(mp->b_next);
srp->sr_mpp = &(srp->sr_mp);
*(srp->sr_mpp) = mp;
srp->sr_mpp = &(mp->b_next);
ASSERT(srp->sr_mpp == &(srp->sr_mp));
*(srp->sr_mpp) = mp;
srp->sr_mpp = &(mp->b_next);
srp->sr_mpp = &(srp->sr_mp);
srp->sr_mpp = &(srp->sr_mp);
srp->sr_mpp = NULL;
srp->sr_mpp = NULL;