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tribuf: `-formal` option: convert all to logic and detect conflicts

This commit is contained in:
Jannis Harder 2022-03-29 12:11:28 +02:00
parent c1646a00ac
commit bc48500548
1 changed files with 46 additions and 3 deletions
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49
passes/techmap/tribuf.cc
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@ -26,10 +26,12 @@ PRIVATE_NAMESPACE_BEGIN
struct TribufConfig {
bool merge_mode;
bool logic_mode;
bool formal_mode;
TribufConfig() {
merge_mode = false;
logic_mode = false;
formal_mode = false;
}
};
@ -55,7 +57,7 @@ struct TribufWorker {
dict<SigSpec, vector<Cell*>> tribuf_cells;
pool<SigBit> output_bits;
if (config.logic_mode)
if (config.logic_mode || config.formal_mode)
for (auto wire : module->wires())
if (wire->port_output)
for (auto bit : sigmap(wire))
@ -102,22 +104,54 @@ struct TribufWorker {
}
}
if (config.merge_mode || config.logic_mode)
if (config.merge_mode || config.logic_mode || config.formal_mode)
{
for (auto &it : tribuf_cells)
{
bool no_tribuf = false;
if (config.logic_mode) {
if (config.logic_mode && !config.formal_mode) {
no_tribuf = true;
for (auto bit : it.first)
if (output_bits.count(bit))
no_tribuf = false;
}
if (config.formal_mode)
no_tribuf = true;
if (GetSize(it.second) <= 1 && !no_tribuf)
continue;
if (config.formal_mode && GetSize(it.second) >= 2) {
for (auto cell : it.second) {
SigSpec others_s;
for (auto other_cell : it.second) {
if (other_cell == cell)
continue;
else if (other_cell->type == ID($tribuf))
others_s.append(other_cell->getPort(ID::EN));
else
others_s.append(other_cell->getPort(ID::E));
}
auto cell_s = cell->type == ID($tribuf) ? cell->getPort(ID::EN) : cell->getPort(ID::E);
auto other_s = module->ReduceOr(NEW_ID, others_s);
auto conflict = module->And(NEW_ID, cell_s, other_s);
std::string name = stringf("$tribuf_conflict$%s", log_id(cell->name));
auto assert_cell = module->addAssert(name, module->Not(NEW_ID, conflict), SigSpec(true));
assert_cell->set_src_attribute(cell->get_src_attribute());
assert_cell->set_bool_attribute(ID::keep);
module->design->scratchpad_set_bool("tribuf.added_something", true);
}
}
SigSpec pmux_b, pmux_s;
for (auto cell : it.second) {
if (cell->type == ID($tribuf))
@ -159,6 +193,11 @@ struct TribufPass : public Pass {
log(" convert tri-state buffers that do not drive output ports\n");
log(" to non-tristate logic. this option implies -merge.\n");
log("\n");
log(" -formal\n");
log(" convert all tri-state buffers to non-tristate logic and\n");
log(" add a formal assertion that no two buffers are driving the\n");
log(" same net simultaneously. this option implies -merge.\n");
log("\n");
}
void execute(std::vector<std::string> args, RTLIL::Design *design) override
{
@ -176,6 +215,10 @@ struct TribufPass : public Pass {
config.logic_mode = true;
continue;
}
if (args[argidx] == "-formal") {
config.formal_mode = true;
continue;
}
break;
}
extra_args(args, argidx, design);