OPA_16B_SLID_MASK
lrh2 = (lrh2 & ~OPA_16B_SLID_MASK) |
(((hdr->lrh[2] & OPA_16B_SLID_MASK) >>
h[2] |= ((slid >> (20 - OPA_16B_SLID_HIGH_SHFT)) & OPA_16B_SLID_MASK);