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Add comments to lb router and extract a private function for routing a single net

This commit is contained in:
tangxifan 2020-03-12 11:05:38 -06:00
parent cd50155e29
commit a1f19e776e
2 changed files with 83 additions and 53 deletions
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129
openfpga/src/repack/lb_router.cpp
View File

@ -202,6 +202,80 @@ void LbRouter::set_physical_pb_modes(const LbRRGraph& lb_rr_graph,
}
}
bool LbRouter::try_route_net(const LbRRGraph& lb_rr_graph,
const AtomNetlist& atom_nlist,
const NetId& net_idx,
t_expansion_node& exp_node,
std::unordered_map<const t_pb_graph_node*, const t_mode*>& mode_map,
const int& verbosity) {
bool is_impossible = false;
if (is_skip_route_net(lb_rr_graph, lb_net_rt_trees_[net_idx])) {
return true;
}
commit_remove_rt(lb_rr_graph, lb_net_rt_trees_[net_idx], RT_REMOVE, mode_map);
free_net_rt(lb_net_rt_trees_[net_idx]);
lb_net_rt_trees_[net_idx] = nullptr;
add_source_to_rt(net_idx);
/* Route each sink of net */
for (size_t isink = 1; isink < lb_net_terminals_[net_idx].size() && !is_impossible; ++isink) {
pq_.clear();
/* Get lowest cost next node, repeat until a path is found or if it is impossible to route */
expand_rt(net_idx, net_idx);
is_impossible = try_expand_nodes(atom_nlist, lb_rr_graph, net_idx, exp_node, isink, mode_status_.expand_all_modes, verbosity);
if (is_impossible && !mode_status_.expand_all_modes) {
mode_status_.try_expand_all_modes = true;
mode_status_.expand_all_modes = true;
break;
}
if (exp_node.node_index == lb_net_terminals_[net_idx][isink]) {
/* Net terminal is routed, add this to the route tree, clear data structures, and keep going */
is_impossible = add_to_rt(lb_net_rt_trees_[net_idx], exp_node.node_index, net_idx);
}
if (is_impossible) {
VTR_LOG("Routing was impossible!\n");
} else if (mode_status_.expand_all_modes) {
is_impossible = route_has_conflict(lb_rr_graph, lb_net_rt_trees_[net_idx]);
if (is_impossible) {
VTR_LOG("Routing was impossible due to modes!\n");
}
}
explore_id_index_++;
if (explore_id_index_ > 2000000000) {
/* overflow protection */
for (const LbRRNodeId& id : lb_rr_graph.nodes()) {
explored_node_tb_[id].explored_id = OPEN;
explored_node_tb_[id].enqueue_id = OPEN;
explore_id_index_ = 1;
}
}
}
/* If routing succeed so far, we will try to save(commit) results
* to route tree.
* During this process, we will check if there is any
* nodes using different modes under the same pb_type
* If so, we have conflicts and routing is considered to be failure
*/
if (!is_impossible) {
commit_remove_rt(lb_rr_graph, lb_net_rt_trees_[net_idx], RT_COMMIT, mode_map);
if (mode_status_.is_mode_conflict) {
is_impossible = true;
}
}
return !is_impossible;
}
bool LbRouter::try_route(const LbRRGraph& lb_rr_graph,
const AtomNetlist& atom_nlist,
const int& verbosity) {
@ -238,60 +312,9 @@ bool LbRouter::try_route(const LbRRGraph& lb_rr_graph,
/* Iterate across all nets internal to logic block */
for (inet = 0; inet < lb_net_ids_.size() && !is_impossible; inet++) {
NetId net_idx = NetId(inet);
if (is_skip_route_net(lb_rr_graph, lb_net_rt_trees_[net_idx])) {
continue;
}
commit_remove_rt(lb_rr_graph, lb_net_rt_trees_[net_idx], RT_REMOVE, mode_map);
free_net_rt(lb_net_rt_trees_[net_idx]);
lb_net_rt_trees_[net_idx] = nullptr;
add_source_to_rt(net_idx);
/* Route each sink of net */
for (unsigned int isink = 1; isink < lb_net_terminals_[net_idx].size() && !is_impossible; isink++) {
pq_.clear();
/* Get lowest cost next node, repeat until a path is found or if it is impossible to route */
expand_rt(net_idx, net_idx);
is_impossible = try_expand_nodes(atom_nlist, lb_rr_graph, net_idx, exp_node, isink, mode_status_.expand_all_modes, verbosity);
if (is_impossible && !mode_status_.expand_all_modes) {
mode_status_.try_expand_all_modes = true;
mode_status_.expand_all_modes = true;
break;
}
if (exp_node.node_index == lb_net_terminals_[net_idx][isink]) {
/* Net terminal is routed, add this to the route tree, clear data structures, and keep going */
is_impossible = add_to_rt(lb_net_rt_trees_[net_idx], exp_node.node_index, net_idx);
}
if (is_impossible) {
VTR_LOG("Routing was impossible!\n");
} else if (mode_status_.expand_all_modes) {
is_impossible = route_has_conflict(lb_rr_graph, lb_net_rt_trees_[net_idx]);
if (is_impossible) {
VTR_LOG("Routing was impossible due to modes!\n");
}
}
explore_id_index_++;
if (explore_id_index_ > 2000000000) {
/* overflow protection */
for (const LbRRNodeId& id : lb_rr_graph.nodes()) {
explored_node_tb_[id].explored_id = OPEN;
explored_node_tb_[id].enqueue_id = OPEN;
explore_id_index_ = 1;
}
}
}
if (!is_impossible) {
commit_remove_rt(lb_rr_graph, lb_net_rt_trees_[net_idx], RT_COMMIT, mode_map);
if (mode_status_.is_mode_conflict) {
is_impossible = true;
}
if (false == try_route_net(lb_rr_graph, atom_nlist, net_idx, exp_node, mode_map, verbosity)) {
is_impossible = true;
}
}

7
openfpga/src/repack/lb_router.h
View File

@ -320,6 +320,13 @@ class LbRouter {
const bool& try_other_modes,
const int& verbosity);
bool try_route_net(const LbRRGraph& lb_rr_graph,
const AtomNetlist& atom_nlist,
const NetId& net_idx,
t_expansion_node& exp_node,
std::unordered_map<const t_pb_graph_node*, const t_mode*>& mode_map,
const int& verbosity);
private : /* Private validators */
/**
* Validate if the rr_graph is the one we used to initialize the router