diff options
Diffstat (limited to 'passes')
| -rw-r--r-- | passes/techmap/dff2dffs.cc | 29 |
1 files changed, 26 insertions, 3 deletions
diff --git a/passes/techmap/dff2dffs.cc b/passes/techmap/dff2dffs.cc index 0ea033513..3fa1ed5cf 100644 --- a/passes/techmap/dff2dffs.cc +++ b/passes/techmap/dff2dffs.cc @@ -34,11 +34,16 @@ struct Dff2dffsPass : public Pass { log("Merge synchronous set/reset $_MUX_ cells to create $__DFFS_[NP][NP][01], to be run before\n"); log("dff2dffe for SR over CE priority.\n"); log("\n"); + log(" -match-init\n"); + log(" Disallow merging synchronous set/reset that has polarity opposite of the\n"); + log(" output wire's init attribute (if any).\n"); + log("\n"); } void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE { log_header(design, "Executing dff2dffs pass (merge synchronous set/reset into FF cells).\n"); + bool match_init = false; size_t argidx; for (argidx = 1; argidx < args.size(); argidx++) { @@ -46,6 +51,10 @@ struct Dff2dffsPass : public Pass { // singleton_mode = true; // continue; // } + if (args[argidx] == "-match-init") { + match_init = true; + continue; + } break; } extra_args(args, argidx, design); @@ -96,9 +105,6 @@ struct Dff2dffsPass : public Pass { SigBit bit_b = sigmap(mux_cell->getPort(ID::B)); SigBit bit_s = sigmap(mux_cell->getPort(ID(S))); - log(" Merging %s (A=%s, B=%s, S=%s) into %s (%s).\n", log_id(mux_cell), - log_signal(bit_a), log_signal(bit_b), log_signal(bit_s), log_id(cell), log_id(cell->type)); - SigBit sr_val, sr_sig; bool invert_sr; sr_sig = bit_s; @@ -113,6 +119,23 @@ struct Dff2dffsPass : public Pass { invert_sr = false; } + if (match_init) { + SigBit bit_q = cell->getPort(ID(Q)); + if (bit_q.wire) { + auto it = bit_q.wire->attributes.find(ID(init)); + if (it != bit_q.wire->attributes.end()) { + auto init_val = it->second[bit_q.offset]; + if (init_val == State::S1 && sr_val != State::S1) + continue; + if (init_val == State::S0 && sr_val != State::S0) + continue; + } + } + } + + log(" Merging %s (A=%s, B=%s, S=%s) into %s (%s).\n", log_id(mux_cell), + log_signal(bit_a), log_signal(bit_b), log_signal(bit_s), log_id(cell), log_id(cell->type)); + if (sr_val == State::S1) { if (cell->type == ID($_DFF_N_)) { if (invert_sr) cell->type = ID($__DFFS_NN1_); |