diff options
Diffstat (limited to 'common')
| -rw-r--r-- | common/timing_opt.cc | 114 |
1 files changed, 114 insertions, 0 deletions
diff --git a/common/timing_opt.cc b/common/timing_opt.cc index abfe5cf1..c7ecd814 100644 --- a/common/timing_opt.cc +++ b/common/timing_opt.cc @@ -194,6 +194,120 @@ unbind: return found_count; } + std::vector<std::vector<PortRef*>> find_crit_paths(float crit_thresh, int max_count) { + std::vector<std::vector<PortRef*>> crit_paths; + std::vector<std::pair<NetInfo *, int>> crit_nets; + std::vector<IdString> netnames; + std::transform(ctx->nets.begin(), ctx->nets.end(), std::back_inserter(netnames), + [](const std::pair<IdString, std::unique_ptr<NetInfo>> &kv){ + return kv.first; + }); + ctx->sorted_shuffle(netnames); + for (auto net : netnames) { + if (crit_nets.size() >= max_count) + break; + if (!net_crit.count(net)) + continue; + auto crit_user = std::max_element(net_crit[net].criticality.begin(), + net_crit[net].criticality.end()); + if (*crit_user > crit_thresh) + crit_nets.push_back(std::make_pair(ctx->nets[net].get(), crit_user - net_crit[net].criticality.begin())); + } + + auto port_user_index = [](CellInfo *cell, PortInfo &port) -> size_t { + NPNR_ASSERT(port.net != nullptr); + for (size_t i = 0; i < port.net->users.size(); i++) { + auto &usr = port.net->users.at(i); + if (usr.cell == cell && usr.port == port.name) + return i; + } + NPNR_ASSERT_FALSE("port user not found on net"); + }; + + for (auto crit_net : crit_nets) { + std::deque<PortRef*> crit_path; + + // FIXME: This will fail badly on combinational loops + + // Iterate backwards following greatest criticality + NetInfo* back_cursor = crit_net.first; + while (back_cursor != nullptr) { + float max_crit = 0; + std::pair<NetInfo *, size_t> crit_sink{nullptr, 0}; + CellInfo *cell = back_cursor->driver.cell; + if (cell == nullptr) + break; + for (auto port : cell->ports) { + if (port.second.type != PORT_IN) + continue; + NetInfo *pn = port.second.net; + if (pn == nullptr) + continue; + if (!net_crit.count(pn->name) || net_crit.at(pn->name).criticality.empty()) + continue; + int ccount; + DelayInfo combDelay; + TimingPortClass tpclass = ctx->getPortTimingClass(cell, port.first, ccount); + if (tpclass != TMG_COMB_INPUT && tpclass != TMG_REGISTER_INPUT) + continue; + bool is_path = ctx->getCellDelay(cell, port.first, back_cursor->driver.port, combDelay); + if (!is_path) + continue; + size_t user_idx = port_user_index(cell, port.second); + float usr_crit = net_crit.at(pn->name).criticality.at(user_idx); + if (usr_crit >= max_crit) { + max_crit = usr_crit; + crit_sink = std::make_pair(pn, user_idx); + } + } + + if (crit_sink.first != nullptr) { + crit_path.push_front(&(crit_sink.first->users.at(crit_sink.second))); + } + back_cursor = crit_sink.first; + } + // Iterate forwards following greatest criticiality + PortRef *fwd_cursor = &(crit_net.first->users.at(crit_net.second)); + while (fwd_cursor != nullptr) { + crit_path.push_back(fwd_cursor); + float max_crit = 0; + std::pair<NetInfo *, size_t> crit_sink{nullptr, 0}; + CellInfo *cell = fwd_cursor->cell; + for (auto port : cell->ports) { + if (port.second.type != PORT_OUT) + continue; + NetInfo *pn = port.second.net; + if (pn == nullptr) + continue; + if (!net_crit.count(pn->name) || net_crit.at(pn->name).criticality.empty()) + continue; + int ccount; + DelayInfo combDelay; + TimingPortClass tpclass = ctx->getPortTimingClass(cell, port.first, ccount); + if (tpclass != TMG_COMB_OUTPUT && tpclass != TMG_REGISTER_OUTPUT) + continue; + auto &crits = net_crit.at(pn->name).criticality; + auto most_crit_usr = std::max_element(crits.begin(), crits.end()); + if (*most_crit_usr >= max_crit) { + max_crit = *most_crit_usr; + crit_sink = std::make_pair(pn, std::distance(crits.begin(), most_crit_usr)); + } + } + if (crit_sink.first != nullptr) { + fwd_cursor = &(crit_sink.first->users.at(crit_sink.second)); + } else { + fwd_cursor = nullptr; + } + } + + std::vector<PortRef*> crit_path_vec; + std::copy(crit_path.begin(), crit_path.end(), std::back_inserter(crit_path_vec)); + crit_paths.push_back(crit_path_vec); + } + + return crit_paths; + } + // Current candidate Bels for cells (linked in both direction> std::vector<IdString> path_cells; std::unordered_map<IdString, std::unordered_set<BelId>> cell_neighbour_bels; |