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author | Clifford Wolf <clifford@clifford.at> | 2019-04-20 01:15:48 +0200 |
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committer | Clifford Wolf <clifford@clifford.at> | 2019-04-20 01:15:48 +0200 |
commit | 37728520a6d559a9f9a0082ddb3d596e8a634d97 (patch) | |
tree | fa85397d93860068443a647901ce844751f71640 /passes/opt/pmux2shiftx.cc | |
parent | 0070184ea9dea56d1dfd8268035bc01a3e340add (diff) | |
download | yosys-37728520a6d559a9f9a0082ddb3d596e8a634d97.tar.gz yosys-37728520a6d559a9f9a0082ddb3d596e8a634d97.tar.bz2 yosys-37728520a6d559a9f9a0082ddb3d596e8a634d97.zip |
Improvements in "pmux2shiftx"
Signed-off-by: Clifford Wolf <clifford@clifford.at>
Diffstat (limited to 'passes/opt/pmux2shiftx.cc')
-rw-r--r-- | passes/opt/pmux2shiftx.cc | 64 |
1 files changed, 52 insertions, 12 deletions
diff --git a/passes/opt/pmux2shiftx.cc b/passes/opt/pmux2shiftx.cc index d0f41cb07..e6a0bd06b 100644 --- a/passes/opt/pmux2shiftx.cc +++ b/passes/opt/pmux2shiftx.cc @@ -33,23 +33,41 @@ struct Pmux2ShiftxPass : public Pass { log("\n"); log("This pass transforms $pmux cells to $shiftx cells.\n"); log("\n"); - log(" -density non_offset_percentage offset_percentage\n"); + log(" -min_density <non_offset_percentage> <offset_percentage>\n"); log(" specifies the minimum density for non_offset- and for offset-mode\n"); log(" default values are 30 (non-offset) and 50 (offset)\n"); log("\n"); + log(" -min_choices <int>\n"); + log(" specified the minimum number of choices for a control signal\n"); + log(" defaukt: 3\n"); + log("\n"); + log(" -allow_onehot\n"); + log(" by default, pmuxes with one-hot encoded control signals are not\n"); + log(" converted. this option disables that check.\n"); + log("\n"); } void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE { - int non_offset_percentage = 30; - int offset_percentage = 50; + int min_non_offset_percentage = 30; + int min_offset_percentage = 50; + int min_choices = 3; + bool allow_onehot = false; log_header(design, "Executing PMUX2SHIFTX pass.\n"); size_t argidx; for (argidx = 1; argidx < args.size(); argidx++) { - if (args[argidx] == "-density" && argidx+2 < args.size()) { - non_offset_percentage = atoi(args[++argidx].c_str()); - offset_percentage = atoi(args[++argidx].c_str()); + if (args[argidx] == "-min_density" && argidx+2 < args.size()) { + min_non_offset_percentage = atoi(args[++argidx].c_str()); + min_offset_percentage = atoi(args[++argidx].c_str()); + continue; + } + if (args[argidx] == "-min_choices" && argidx+1 < args.size()) { + min_choices = atoi(args[++argidx].c_str()); + continue; + } + if (args[argidx] == "-allow_onehot") { + allow_onehot = true; continue; } break; @@ -163,8 +181,7 @@ struct Pmux2ShiftxPass : public Pass { if (seldb.empty()) continue; - log("Inspecting $pmux cell %s/%s.\n", log_id(module), log_id(cell)); - log(" data width: %d (next power-of-2 = %d, log2 = %d)\n", width, extwidth, width_bits); + bool printed_pmux_header = false; SigSpec updated_S = cell->getPort("\\S"); SigSpec updated_B = cell->getPort("\\B"); @@ -180,17 +197,40 @@ struct Pmux2ShiftxPass : public Pass { sig = it.first; } - log(" checking ctrl signal %s\n", log_signal(sig)); - // find the relevant choices + bool is_onehot = true; dict<Const, int> choices; for (int i : seldb.at(sig)) { Const val = eqdb.at(S[i]).second; + int onebits = 0; + for (auto b : val.bits) + if (b == State::S1) + onebits++; + if (onebits > 1) + is_onehot = false; choices[val] = i; } // TBD: also find choices that are using signals that are subsets of the bits in "sig" + if (is_onehot && !allow_onehot) { + seldb.erase(sig); + continue; + } + + if (GetSize(choices) < min_choices) { + seldb.erase(sig); + continue; + } + + if (!printed_pmux_header) { + printed_pmux_header = true; + log("Inspecting $pmux cell %s/%s.\n", log_id(module), log_id(cell)); + log(" data width: %d (next power-of-2 = %d, log2 = %d)\n", width, extwidth, width_bits); + } + + log(" checking ctrl signal %s\n", log_signal(sig)); + // find the best permutation vector<int> perm_new_from_old(GetSize(sig)); Const perm_xormask(State::S0, GetSize(sig)); @@ -329,7 +369,7 @@ struct Pmux2ShiftxPass : public Pass { // check density percentages Const offset(State::S0, GetSize(sig)); - if (absolute_density < non_offset_percentage && range_density >= offset_percentage) + if (absolute_density < min_non_offset_percentage && range_density >= min_offset_percentage) { offset = Const(min_choice, GetSize(sig)); log(" offset: %s\n", log_signal(offset)); @@ -342,7 +382,7 @@ struct Pmux2ShiftxPass : public Pass { new_perm_choices[const_sub(it.first, offset, false, false, GetSize(sig))] = it.second; perm_choices.swap(new_perm_choices); } else - if (absolute_density < non_offset_percentage) { + if (absolute_density < min_non_offset_percentage) { log(" insufficient density.\n"); seldb.erase(sig); continue; |