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If driver not found, use LUT2

This commit is contained in:
Eddie Hung 2019-05-27 23:12:21 -07:00
parent 3eec100748
commit 89bd6b8504
1 changed files with 27 additions and 29 deletions
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56
passes/techmap/abc9.cc
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@ -588,30 +588,34 @@ void abc9_module(RTLIL::Design *design, RTLIL::Module *current_module, std::stri
RTLIL::SigBit a_bit = c->getPort("\\A").as_bit();
RTLIL::SigBit y_bit = c->getPort("\\Y").as_bit();
if (!lut_costs.empty() || !lut_file.empty()) {
RTLIL::Cell* driving_lut = nullptr;
// ABC can return NOT gates that drive POs
if (a_bit.wire->port_input) {
// If it's a NOT gate that comes from a primary input directly
// then implement it using a LUT
cell = module->addLut(remap_name(stringf("%s$lut", c->name.c_str())),
RTLIL::SigBit(module->wires_[remap_name(a_bit.wire->name)], a_bit.offset),
RTLIL::SigBit(module->wires_[remap_name(y_bit.wire->name)], y_bit.offset),
1);
}
else {
// Otherwise, clone the driving LUT to guarantee that we
// won't increase the max logic depth
if (!a_bit.wire->port_input) {
// If it's not a NOT gate that that comes from a PI directly,
// find the driving LUT and clone that to guarantee that we won't
// increase the max logic depth
// (TODO: Optimise by not cloning unless will increase depth)
RTLIL::IdString driver_name;
if (GetSize(a_bit.wire) == 1)
driver_name = stringf("%s$lut", a_bit.wire->name.c_str());
else
driver_name = stringf("%s[%d]$lut", a_bit.wire->name.c_str(), a_bit.offset);
RTLIL::Cell* driver = mapped_mod->cell(driver_name);
log_assert(driver);
auto driver_a = driver->getPort("\\A").chunks();
driving_lut = mapped_mod->cell(driver_name);
}
if (!driving_lut) {
// If a driver couldn't be found (could be from PI,
// or from a box) then implement using a LUT
cell = module->addLut(remap_name(stringf("%s$lut", c->name.c_str())),
RTLIL::SigBit(module->wires_[remap_name(a_bit.wire->name)], a_bit.offset),
RTLIL::SigBit(module->wires_[remap_name(y_bit.wire->name)], y_bit.offset),
1);
}
else {
auto driver_a = driving_lut->getPort("\\A").chunks();
for (auto &chunk : driver_a)
chunk.wire = module->wires_[remap_name(chunk.wire->name)];
RTLIL::Const driver_lut = driver->getParam("\\LUT");
RTLIL::Const driver_lut = driving_lut->getParam("\\LUT");
for (auto &b : driver_lut.bits) {
if (b == RTLIL::State::S0) b = RTLIL::State::S1;
else if (b == RTLIL::State::S1) b = RTLIL::State::S0;
@ -867,20 +871,14 @@ void abc9_module(RTLIL::Design *design, RTLIL::Module *current_module, std::stri
// module->connect(conn);
// }
// Go through all AND, NOT, and ABC box instances,
// and disconnect their output connections in
// preparation for stitching mapped_mod in
for (auto cell : module->cells()) {
if (!cell->type.in("$_AND_", "$_NOT_")) {
RTLIL::Module* cell_module = design->module(cell->type);
if (!cell_module || !cell_module->attributes.count("\\abc_box_id"))
continue;
}
for (auto &it : cell->connections_) {
auto port_name = it.first;
if (!cell->output(port_name)) continue;
it.second = RTLIL::SigSpec();
}
// Remove all AND, NOT, instances
// in preparation for stitching mapped_mod in
for (auto it = module->cells_.begin(); it != module->cells_.end(); ) {
RTLIL::Cell* cell = it->second;
if (cell->type.in("$_AND_", "$_NOT_"))
it = module->cells_.erase(it);
else
++it;
}
// Do the same for module connections
for (auto &it : module->connections_) {