/**
* Adapted from breadth_first_route_net()
*/
boolean inc_breadth_first_route_net(int inet, float bend_cost, struct s_trace **old_trace_tail, int old_num_nets, struct s_router_opts *router_opts)
{
/* Uses a maze routing (Dijkstra's) algorithm to route a net. The net *
* begins at the net output, and expands outward until it hits a target *
* pin. The algorithm is then restarted with the entire first wire segment *
* included as part of the source this time. For an n-pin net, the maze *
* router is invoked n-1 times to complete all the connections. Inet is *
* the index of the net to be routed. Bends are penalized by bend_cost *
* (which is typically zero for detailed routing and nonzero only for global *
* routing), since global routes with lots of bends are tougher to detailed *
* route (using a detailed router like SEGA). *
* If this routine finds that a net *cannot* be connected (due to a complete *
* lack of potential paths, rather than congestion), it returns FALSE, as *
* routing is impossible on this architecture. Otherwise it returns TRUE. */
int inode, prev_node, remaining_connections_to_sink;
int itarget, target_inode, target_iblk;
int max_mdist;
float pcost, new_pcost;
struct s_heap *current;
struct s_trace *tptr;
/* Rip up incremental trace only */
inc_free_traceback(inet, old_trace_tail);
inode = net_rr_terminals[inet][0];
/* EH: Extract the assigned TB target */
itarget = clb_net[inet].num_sinks;
target_inode = net_rr_terminals[inet][itarget+1];
assert(target_inode != OPEN);
target_iblk = clb_net[inet].node_block[itarget+1];
/* If LE symmetry enabled, and inet was local, add all CLB_OPINs
* from other local nets onto heap too */
if (router_opts->inc_le_symmetry && inet >= old_num_nets)
{
int num_sources, *sources;
int i;
boolean found = FALSE;
num_sources = inc_local_OPINs(inet, old_num_nets, &sources);
for (i = 0; i < num_sources; i++)
{
inc_breadth_first_add_inode_to_heap(sources[i]);
if (sources[i] == inode)
found = TRUE;
}
assert(found == TRUE);
free(sources);
}
else
{
breadth_first_add_source_to_heap(inet);
}
/*mark_ends(inet); */
tptr = trace_head[inet];
remaining_connections_to_sink = 0;
max_mdist = 0;
/* for(i = 1; i <= clb_net[inet].num_sinks; i++) */
{ /* Need n-1 wires to connect n pins */
breadth_first_expand_trace_segment(tptr,
remaining_connections_to_sink);
current = get_heap_head();
if(current == NULL)
{ /* Infeasible routing. No possible path for net. */
reset_path_costs(); /* Clean up before leaving. */
return (FALSE);
}
inode = current->index;
/*while(rr_node_route_inf[inode].target_flag == 0)*/
while(rr_node_route_inf[inode].target_flag != target_iblk)
{
/*max_mdist = max(max_mdist, inc_traceback_len(current));*/
pcost = rr_node_route_inf[inode].path_cost;
new_pcost = current->cost;
if(pcost > new_pcost)
{ /* New path is lowest cost. */
rr_node_route_inf[inode].path_cost = new_pcost;
prev_node = current->u.prev_node;
rr_node_route_inf[inode].prev_node = prev_node;
rr_node_route_inf[inode].prev_edge =
current->prev_edge;
if(pcost > 0.99 * HUGE_POSITIVE_FLOAT) /* First time touched. */
add_to_mod_list(&rr_node_route_inf[inode].
path_cost);
inc_breadth_first_expand_neighbours(inode, new_pcost,
inet, bend_cost);
}
free_heap_data(current);
current = get_heap_head();
if(current == NULL)
{ /* Impossible routing. No path for net. */
fprintf(stdout, "\ninet %d (vnet %d) failed", inet, clb_to_vpack_net_mapping[inet]);
empty_heap();
reset_path_costs();
return (FALSE);
}
inode = current->index;
}
/*rr_node_route_inf[inode].target_flag--;*/ /* Connected to this SINK. */
remaining_connections_to_sink =
rr_node_route_inf[inode].target_flag;
tptr = update_traceback(current, inet);
free_heap_data(current);
}
/*printf("max_mdist = %d\n", max_mdist);*/
empty_heap();
reset_path_costs();
return (TRUE);
}
static boolean breadth_first_route_net (int inet, float bend_cost) {
/* Uses a maze routing (Dijkstra's) algorithm to route a net. The net *
* begins at the net output, and expands outward until it hits a target *
* pin. The algorithm is then restarted with the entire first wire segment *
* included as part of the source this time. For an n-pin net, the maze *
* router is invoked n-1 times to complete all the connections. Inet is *
* the index of the net to be routed. Bends are penalized by bend_cost *
* (which is typically zero for detailed routing and nonzero only for global *
* routing), since global routes with lots of bends are tougher to detailed *
* route (using a detailed router like SEGA). *
* If this routine finds that a net *cannot* be connected (due to a complete *
* lack of potential paths, rather than congestion), it returns FALSE, as *
* routing is impossible on this architecture. Otherwise it returns TRUE. */
int i, inode, prev_node, remaining_connections_to_sink;
float pcost, new_pcost;
struct s_heap *current;
struct s_trace *tptr;
free_traceback (inet);
breadth_first_add_source_to_heap (inet);
mark_ends (inet);
tptr = NULL;
remaining_connections_to_sink = 0;
for (i=1;i<net[inet].num_pins;i++) { /* Need n-1 wires to connect n pins */
breadth_first_expand_trace_segment (tptr, remaining_connections_to_sink);
current = get_heap_head();
if (current == NULL) { /* Infeasible routing. No possible path for net. */
reset_path_costs (); /* Clean up before leaving. */
return (FALSE);
}
inode = current->index;
while (rr_node_route_inf[inode].target_flag == 0) {
pcost = rr_node_route_inf[inode].path_cost;
new_pcost = current->cost;
if (pcost > new_pcost) { /* New path is lowest cost. */
rr_node_route_inf[inode].path_cost = new_pcost;
prev_node = current->u.prev_node;
rr_node_route_inf[inode].prev_node = prev_node;
rr_node_route_inf[inode].prev_edge = current->prev_edge;
if (pcost > 0.99 * HUGE_FLOAT) /* First time touched. */
add_to_mod_list (&rr_node_route_inf[inode].path_cost);
breadth_first_expand_neighbours (inode, new_pcost, inet, bend_cost);
}
free_heap_data (current);
current = get_heap_head ();
if (current == NULL) { /* Impossible routing. No path for net. */
reset_path_costs ();
return (FALSE);
}
inode = current->index;
}
rr_node_route_inf[inode].target_flag--; /* Connected to this SINK. */
remaining_connections_to_sink = rr_node_route_inf[inode].target_flag;
tptr = update_traceback (current, inet);
free_heap_data (current);
}
empty_heap ();
reset_path_costs ();
return (TRUE);
}
