diff options
Diffstat (limited to 'techlibs/ice40/ice40_opt.cc')
| -rw-r--r-- | techlibs/ice40/ice40_opt.cc | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/techlibs/ice40/ice40_opt.cc b/techlibs/ice40/ice40_opt.cc index f528607d6..e492454fb 100644 --- a/techlibs/ice40/ice40_opt.cc +++ b/techlibs/ice40/ice40_opt.cc @@ -83,6 +83,51 @@ static void run_ice40_opts(Module *module) } continue; } + + if (cell->type == "$__ICE40_FULL_ADDER") + { + SigSpec non_const_inputs, replacement_output; + int count_zeros = 0, count_ones = 0; + + SigBit inbit[3] = { + cell->getPort("\\A"), + cell->getPort("\\B"), + cell->getPort("\\CI") + }; + for (int i = 0; i < 3; i++) + if (inbit[i].wire == nullptr) { + if (inbit[i] == State::S1) + count_ones++; + else + count_zeros++; + } else + non_const_inputs.append(inbit[i]); + + if (count_zeros >= 2) + replacement_output = State::S0; + else if (count_ones >= 2) + replacement_output = State::S1; + else if (GetSize(non_const_inputs) == 1) + replacement_output = non_const_inputs; + + if (GetSize(replacement_output)) { + optimized_co.insert(sigmap(cell->getPort("\\CO")[0])); + module->connect(cell->getPort("\\CO")[0], replacement_output); + module->design->scratchpad_set_bool("opt.did_something", true); + log("Optimized $__ICE40_FULL_ADDER cell back to logic (without SB_CARRY) %s.%s: CO=%s\n", + log_id(module), log_id(cell), log_signal(replacement_output)); + cell->type = "$lut"; + cell->setPort("\\A", { RTLIL::S0, inbit[0], inbit[1], inbit[2] }); + cell->setPort("\\Y", cell->getPort("\\O")); + cell->unsetPort("\\B"); + cell->unsetPort("\\CI"); + cell->unsetPort("\\CO"); + cell->unsetPort("\\O"); + cell->setParam("\\LUT", RTLIL::Const::from_string("0110100110010110")); + cell->setParam("\\WIDTH", 4); + } + continue; + } } for (auto cell : sb_lut_cells) |