SRC/route_breadth_first.h File Reference

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Functions
boolean	try_breadth_first_route (struct s_router_opts router_opts, t_ivec **fb_opins_used_locally, int width_fac)

---

Function Documentation

boolean try_breadth_first_route	(	struct s_router_opts	router_opts,
		t_ivec **	fb_opins_used_locally,
		int	width_fac
	)

Definition at line 31 of file route_breadth_first.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;

/* 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. */

                            pathfinder_update_one_cost(trace_head[inet], -1,
                                                       pres_fac);

                            is_routable =
                                breadth_first_route_net(inet,
                                                        router_opts.
                                                        bend_cost);

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

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

                            pathfinder_update_one_cost(trace_head[inet], 1,
                                                       pres_fac);

                        }
                }

            /* 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.\n",
                         itry);
                    return (TRUE);
                }

            if(itry == 1)
                        pres_fac = router_opts.initial_pres_fac;
            else
                        pres_fac *= router_opts.pres_fac_mult;

                pres_fac = min (pres_fac, HUGE_FLOAT / 1e5);

            pathfinder_update_cost(pres_fac, router_opts.acc_fac);
        }

    printf("Routing failed.\n");
    return (FALSE);
}

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