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fixup! dfflibmap: refactor

This commit is contained in:
Emil J. Tywoniak 2026-03-03 17:24:34 +01:00
parent dc70d58b76
commit 9a8d8886e1
1 changed files with 18 additions and 20 deletions
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38
passes/techmap/dfflibmap.cc
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@ -58,14 +58,8 @@ struct CellMatch {
int num_pins = 0;
bool has_noninv_output = false;
enum ScanResult {
REJECT, // cell has unconnected inputs
NO_OUTPUT, // cell is valid but has no Q/QN output
OK // cell is valid with output found
};
// Scan cell pins to count them, check inputs, and identify Q/QN outputs.
ScanResult scan_outputs(const LibertyAst *cell, const LibertyAst *ff, bool cell_next_pol)
bool find_outputs(const LibertyAst *cell, const LibertyAst *ff, bool cell_next_pol)
{
bool found_output = false;
for (auto pin : cell->children) {
@ -76,7 +70,7 @@ struct CellMatch {
continue;
num_pins++;
if (dir->value == "input" && ports.count(pin->args[0]) == 0)
return REJECT;
return false;
const LibertyAst *func = pin->find("function");
if (dir->value == "output" && func != nullptr) {
std::string value = func->value;
@ -84,18 +78,20 @@ struct CellMatch {
// next_state negation propagated to output
if (value == ff->args[0]) {
ports[pin->args[0]] = cell_next_pol ? 'Q' : 'q';
if (cell_next_pol) has_noninv_output = true;
if (cell_next_pol)
has_noninv_output = true;
found_output = true;
} else if (value == ff->args[1]) {
ports[pin->args[0]] = cell_next_pol ? 'q' : 'Q';
if (!cell_next_pol) has_noninv_output = true;
if (!cell_next_pol)
has_noninv_output = true;
found_output = true;
}
}
if (ports.count(pin->args[0]) == 0)
ports[pin->args[0]] = 0;
}
return found_output ? OK : NO_OUTPUT;
return found_output;
}
};
@ -236,6 +232,7 @@ static bool parse_next_state(const LibertyAst *cell, const LibertyAst *attr, std
return false;
}
// TODO refactor this enable pin logic
data_not_inverted = true;
data_name = "";
enable_not_inverted = true;
@ -357,13 +354,14 @@ struct DffFinder {
CellMatch match;
match.ports[cell_clk_pin] = 'C';
if (ff.has_arst) match.ports[cell_rst_pin] = 'R';
if (ff.has_ce) match.ports[cell_enable_pin] = 'E';
if (ff.has_arst)
match.ports[cell_rst_pin] = 'R';
if (ff.has_ce)
match.ports[cell_enable_pin] = 'E';
match.ports[cell_next_pin] = 'D';
if (match.scan_outputs(cell, cell_ff, cell_next_pol) != CellMatch::OK)
continue;
best.update(cell, match);
if (match.find_outputs(cell, cell_ff, cell_next_pol))
best.update(cell, match);
}
best.record_mapping(cell_type);
}
@ -404,12 +402,12 @@ struct DffFinder {
match.ports[cell_clk_pin] = 'C';
match.ports[cell_set_pin] = 'S';
match.ports[cell_clr_pin] = 'R';
if (ff.has_ce) match.ports[cell_enable_pin] = 'E';
if (ff.has_ce)
match.ports[cell_enable_pin] = 'E';
match.ports[cell_next_pin] = 'D';
if (match.scan_outputs(cell, cell_ff, cell_next_pol) != CellMatch::OK)
continue;
best.update(cell, match);
if (match.find_outputs(cell, cell_ff, cell_next_pol))
best.update(cell, match);
}
best.record_mapping(cell_type);
}