diff options
Diffstat (limited to 'passes/techmap/clkbufmap.cc')
| -rw-r--r-- | passes/techmap/clkbufmap.cc | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/passes/techmap/clkbufmap.cc b/passes/techmap/clkbufmap.cc index 246932d81..b9cd68883 100644 --- a/passes/techmap/clkbufmap.cc +++ b/passes/techmap/clkbufmap.cc @@ -115,6 +115,8 @@ struct ClkbufmapPass : public Pass { // Cell type, port name, bit index. pool<pair<IdString, pair<IdString, int>>> sink_ports; pool<pair<IdString, pair<IdString, int>>> buf_ports; + dict<pair<IdString, pair<IdString, int>>, pair<IdString, int>> inv_ports_out; + dict<pair<IdString, pair<IdString, int>>, pair<IdString, int>> inv_ports_in; // Process submodules before module using them. std::vector<Module *> modules_sorted; @@ -133,6 +135,14 @@ struct ClkbufmapPass : public Pass { if (wire->get_bool_attribute("\\clkbuf_sink")) for (int i = 0; i < GetSize(wire); i++) sink_ports.insert(make_pair(module->name, make_pair(wire->name, i))); + auto it = wire->attributes.find("\\clkbuf_inv"); + if (it != wire->attributes.end()) { + IdString in_name = RTLIL::escape_id(it->second.decode_string()); + for (int i = 0; i < GetSize(wire); i++) { + inv_ports_out[make_pair(module->name, make_pair(wire->name, i))] = make_pair(in_name, i); + inv_ports_in[make_pair(module->name, make_pair(in_name, i))] = make_pair(wire->name, i); + } + } } continue; } @@ -157,6 +167,37 @@ struct ClkbufmapPass : public Pass { if (buf_ports.count(make_pair(cell->type, make_pair(port.first, i)))) buf_wire_bits.insert(sigmap(port.second[i])); + // Third, propagate tags through inverters. + bool retry = true; + while (retry) { + retry = false; + for (auto cell : module->cells()) + for (auto port : cell->connections()) + for (int i = 0; i < port.second.size(); i++) { + auto it = inv_ports_out.find(make_pair(cell->type, make_pair(port.first, i))); + auto bit = sigmap(port.second[i]); + // If output of an inverter is connected to a sink, mark it as buffered, + // and request a buffer on the inverter's input instead. + if (it != inv_ports_out.end() && !buf_wire_bits.count(bit) && sink_wire_bits.count(bit)) { + buf_wire_bits.insert(bit); + auto other_bit = sigmap(cell->getPort(it->second.first)[it->second.second]); + sink_wire_bits.insert(other_bit); + retry = true; + } + // If input of an inverter is marked as already-buffered, + // mark its output already-buffered as well. + auto it2 = inv_ports_in.find(make_pair(cell->type, make_pair(port.first, i))); + if (it2 != inv_ports_in.end() && buf_wire_bits.count(bit)) { + auto other_bit = sigmap(cell->getPort(it2->second.first)[it2->second.second]); + if (!buf_wire_bits.count(other_bit)) { + buf_wire_bits.insert(other_bit); + retry = true; + } + } + + } + }; + // Collect all driven bits. for (auto cell : module->cells()) for (auto port : cell->connections()) |