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Carry in/out to be the last input/output for chains to be preserved

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This commit is contained in:
Eddie Hung 2019-05-30 01:23:36 -07:00
parent 8c58c728a7
commit fdfc18be91
4 changed files with 91 additions and 12 deletions
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38
backends/aiger/xaiger.cc
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@ -298,6 +298,8 @@ struct XAigerWriter
for (auto user_cell : it.second)
toposort.edge(driver_cell, user_cell);
pool<RTLIL::Module*> abc_carry_modules;
toposort.sort();
for (auto cell_name : toposort.sorted) {
RTLIL::Cell *cell = module->cell(cell_name);
@ -305,6 +307,42 @@ struct XAigerWriter
if (!box_module || !box_module->attributes.count("\\abc_box_id"))
continue;
if (box_module->attributes.count("\\abc_carry") && !abc_carry_modules.count(box_module)) {
RTLIL::Wire* carry_in = nullptr, *carry_out = nullptr;
RTLIL::Wire* last_in = nullptr, *last_out = nullptr;
for (const auto &port_name : box_module->ports) {
RTLIL::Wire* w = box_module->wire(port_name);
log_assert(w);
if (w->port_input) {
if (w->attributes.count("\\abc_carry_in")) {
log_assert(!carry_in);
carry_in = w;
}
log_assert(!last_in || last_in->port_id < w->port_id);
last_in = w;
}
if (w->port_output) {
if (w->attributes.count("\\abc_carry_out")) {
log_assert(!carry_out);
carry_out = w;
}
log_assert(!last_out || last_out->port_id < w->port_id);
last_out = w;
}
}
if (carry_in) {
log_assert(last_in);
std::swap(box_module->ports[carry_in->port_id-1], box_module->ports[last_in->port_id-1]);
std::swap(carry_in->port_id, last_in->port_id);
}
if (carry_out) {
log_assert(last_out);
std::swap(box_module->ports[carry_out->port_id-1], box_module->ports[last_out->port_id-1]);
std::swap(carry_out->port_id, last_out->port_id);
}
}
// Fully pad all unused input connections of this box cell with S0
// Fully pad all undriven output connections of this box cell with anonymous wires
// NB: Assume box_module->ports are sorted alphabetically