SRC/route_directed_search.h File Reference

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Functions
boolean	try_directed_search_route (struct s_router_opts router_opts, t_ivec **fb_opins_used_locally, int width_fac, t_mst_edge **mst)

---

Function Documentation

boolean try_directed_search_route	(	struct s_router_opts	router_opts,
		t_ivec **	fb_opins_used_locally,
		int	width_fac,
		t_mst_edge **	mst
	)

Definition at line 48 of file route_directed_search.c.

{

/* Iterated maze router ala Pathfinder Negotiated Congestion algorithm,  *
 * (FPGA 95 p. 111).  Returns TRUE if it can route this FPGA, FALSE if   *
 * it can't.                                                             */

    float pres_fac;
    boolean success, is_routable, rip_up_local_opins;
    int itry, inet;

    /* char msg[100]; */

    /* mst not built as good as it should, ideally, just have it after placement once only
         however, rr_node numbers changed when the channel width changes so forced to do it here */
    if(mst)
        {
            for(inet = 0; inet < num_nets; inet++)
                {
                    free(mst[inet]);
                    mst[inet] = get_mst_of_net(inet);
                }
        }

/* Usually the first iteration uses a very small (or 0) pres_fac to find  *
 * the shortest path and get a congestion map.  For fast compiles, I set  *
 * pres_fac high even for the first iteration.                            */

    pres_fac = router_opts.first_iter_pres_fac;

    for(itry = 1; itry <= router_opts.max_router_iterations; itry++)
        {

            for(inet = 0; inet < num_nets; inet++)
                {
                    if(net[inet].is_global == FALSE)
                        {       /* Skip global nets. */

                            is_routable =
                                directed_search_route_net(inet, pres_fac,
                                                          router_opts.
                                                          astar_fac,
                                                          router_opts.
                                                          bend_cost, mst);

                            /* Impossible to route? (disconnected rr_graph) */

                            if(!is_routable)
                                {
                                    printf("Routing failed.\n");
                                    return (FALSE);
                                }

                        }
                }

            /* Make sure any FB OPINs used up by subblocks being hooked directly     *
             * to them are reserved for that purpose.                                 */

            if(itry == 1)
                rip_up_local_opins = FALSE;
            else
                rip_up_local_opins = TRUE;

            reserve_locally_used_opins(pres_fac, rip_up_local_opins,
                                       fb_opins_used_locally);

            success = feasible_routing();
            if(success)
                {
                    printf
                        ("Successfully routed after %d routing iterations by Directed Search.\n",
                         itry);
                    return (TRUE);
                }
#if 0
            else
                {
                    sprintf(msg,
                            "After iteration %d routing failed (A*) with a channel width factor of %d and Fc_int of %d, Fs_int of %d.",
                            itry, width_fac, Fc_int, Fs_int);
                    init_draw_coords(pins_per_clb);
                    update_screen(MAJOR, msg, ROUTING, FALSE);
                }
#endif


            if(itry == 1)
                {
                    pres_fac = router_opts.initial_pres_fac;
                    pathfinder_update_cost(pres_fac, 0.);       /* Acc_fac=0 for first iter. */
                }
            else
                {
                    pres_fac *= router_opts.pres_fac_mult;
                    pathfinder_update_cost(pres_fac, router_opts.acc_fac);
                }

        }

    printf("Routing failed.\n");

    return (FALSE);
}

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