mirrors/yosys
3
0
Fork 0
mirror of https://github.com/YosysHQ/yosys synced 2025-04-22 00:26:40 +00:00
Code Activity

Clean up muxpack

Browse source
This commit is contained in:
Akash Levy 2025-02-14 06:56:12 -08:00
parent 0f5f9ae28c
commit db83aaee09
1 changed files with 33 additions and 69 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

102
passes/opt/muxpack.cc
View file

@ -135,26 +135,6 @@ struct MuxpackWorker
pool<Cell*> candidate_cells;
ExclusiveDatabase excl_db;
// Splitfanout limit
int limit = -1;
bool fanout_in_range(SigSpec outsig)
{
// Check if output signal is "bit-split", skip if so
// This is a lookahead for the splitfanout pass that has this limitation
auto bit_users = bit_users_db[outsig[0]];
for (int i = 0; i < GetSize(outsig); i++) {
if (bit_users_db[outsig[i]] != bit_users) {
return false;
}
}
// Skip if fanout is above limit
if (limit != -1 && GetSize(bit_users) > limit) {
return false;
}
return true;
}
void make_sig_chain_next_prev()
{
@ -180,10 +160,8 @@ struct MuxpackWorker
for (auto a_bit : a_sig)
sigbit_with_non_chain_users.insert(a_bit);
else {
if (fanout_in_range(y_sig)) {
sig_chain_next[a_sig] = cell;
candidate_cells.insert(cell);
}
sig_chain_next[a_sig] = cell;
candidate_cells.insert(cell);
}
if (!b_sig.empty()) {
@ -191,18 +169,12 @@ struct MuxpackWorker
for (auto b_bit : b_sig)
sigbit_with_non_chain_users.insert(b_bit);
else {
if (fanout_in_range(y_sig)) {
sig_chain_next[b_sig] = cell;
candidate_cells.insert(cell);
}
sig_chain_next[b_sig] = cell;
candidate_cells.insert(cell);
}
}
if (fanout_in_range(y_sig)) {
// Mark cell as the previous in the chain relative to y_sig
sig_chain_prev[y_sig] = cell;
}
sig_chain_prev[y_sig] = cell;
continue;
}
@ -323,26 +295,26 @@ struct MuxpackWorker
}
if (make_excl) {
/* We create the following one-hot select line decoder
S0 S1 S2 S3 ...
| | | |
+--------+ +----------+ +-------------+ |
| _|_ | _|_ | _|_ |
| \_/ | \_/ | \_/ |
| o | o | o |
| | | | | ___ | |
| +----------+ | | / | | |
| | | |___| | / |___| |
| |___| | & | / / | & | / ...
| | & | \___/ / / \___/ / /
| \___/ | | / | | /
| | +------+ +-------+
| | | | | |
| | |___| |___|
| | | & | | & |
| | \___/ \___/
| | | |
S0 S0'S1 S0'S1'S2 S0'S1'S2'S3 ...
/* Create the following one-hot select line decoder:
S0 S1 S2 S3 ...
| | | |
+--------+ +----------+ +-------------+ |
| _|_ | _|_ | _|_ |
| \_/ | \_/ | \_/ |
| o | o | o |
| | | | | ___ | |
| +----------+ | | / | | |
| | | |___| | / |___| |
| |___| | & | / / | & | / ...
| | & | \___/ / / \___/ / /
| \___/ | | / | | /
| | +------+ +-------+
| | | | | |
| | |___| |___|
| | | & | | & |
| | \___/ \___/
| | | |
S0 S0'S1 S0'S1'S2 S0'S1'S2'S3 ...
*/
SigSpec decodedSelect;
Cell *cell = last_cell;
@ -389,11 +361,10 @@ struct MuxpackWorker
}
}
void cleanup(bool remove_cell)
void cleanup()
{
if (remove_cell)
for (auto cell : remove_cells)
module->remove(cell);
for (auto cell : remove_cells)
module->remove(cell);
remove_cells.clear();
sig_chain_next.clear();
@ -402,8 +373,8 @@ struct MuxpackWorker
candidate_cells.clear();
}
MuxpackWorker(Design *design, Module *module, bool assume_excl, bool make_excl, int limit)
: module(module), sigmap(module), mux_count(0), pmux_count(0), excl_db(module, sigmap, assume_excl, make_excl), limit(limit)
MuxpackWorker(Module *module, bool assume_excl, bool make_excl) :
module(module), sigmap(module), mux_count(0), pmux_count(0), excl_db(module, sigmap, assume_excl, make_excl)
{
// Build bit_drivers_db
@ -459,7 +430,7 @@ struct MuxpackWorker
process_chain(chain, make_excl);
}
// Clean up
cleanup(true);
cleanup();
}
};
@ -479,11 +450,9 @@ struct MuxpackPass : public Pass {
log("whose select lines are driven by '$eq' cells with other such cells if it can be\n");
log("certain that their select inputs are mutually exclusive.\n");
log("\n");
log(" -fanout_limit n\n");
log(" max fanout to split.\n");
log("\n");
log(" -assume_excl\n");
log(" assume mutually exclusive constraint when packing (may result in inequivalence)\n");
log("\n");
log(" -make_excl\n");
log(" Adds a one-hot decoder on the control signals\n");
log("\n");
@ -492,17 +461,12 @@ struct MuxpackPass : public Pass {
{
bool assume_excl = false;
bool make_excl = false;
int limit = -1;
log_header(design, "Executing MUXPACK pass ($mux cell cascades to $pmux).\n");
size_t argidx;
for (argidx = 1; argidx < args.size(); argidx++)
{
if (args[argidx] == "-fanout_limit" && argidx + 1 < args.size()) {
limit = std::stoi(args[++argidx]);
continue;
}
if (args[argidx] == "-assume_excl") {
assume_excl = true;
continue;
@ -520,7 +484,7 @@ struct MuxpackPass : public Pass {
int pmux_count = 0;
for (auto module : design->selected_modules()) {
MuxpackWorker worker(design, module, assume_excl, make_excl, limit);
MuxpackWorker worker(module, assume_excl, make_excl);
mux_count += worker.mux_count;
pmux_count += worker.pmux_count;
}