fill_based_sd
fill_based_sd(&sd, r);
fill_based_sd(&td->td_pcb->pcb_fsd, reg->r_fsbase);
fill_based_sd(&td->td_pcb->pcb_gsd, reg->r_gsbase);
fill_based_sd(&sd, base);
fill_based_sd(&sd, base);
void fill_based_sd(struct segment_descriptor *sdp, uint32_t base);