diff options
Diffstat (limited to 'passes/opt')
| -rw-r--r-- | passes/opt/pmux2shiftx.cc | 23 |
1 files changed, 22 insertions, 1 deletions
diff --git a/passes/opt/pmux2shiftx.cc b/passes/opt/pmux2shiftx.cc index 5f897b131..29870f510 100644 --- a/passes/opt/pmux2shiftx.cc +++ b/passes/opt/pmux2shiftx.cc @@ -369,6 +369,7 @@ struct Pmux2ShiftxPass : public Pass { dict<SigSpec, pool<int>> seldb; + SigSpec A = cell->getPort("\\A"); SigSpec B = cell->getPort("\\B"); SigSpec S = sigmap(cell->getPort("\\S")); for (int i = 0; i < GetSize(S); i++) @@ -419,6 +420,8 @@ struct Pmux2ShiftxPass : public Pass { choices[val] = i; } + bool full_pmux = GetSize(choices) == GetSize(S); + // TBD: also find choices that are using signals that are subsets of the bits in "sig" if (!verbose) @@ -634,7 +637,21 @@ struct Pmux2ShiftxPass : public Pass { log(" range density: %d%%\n", range_density); log(" absolute density: %d%%\n", absolute_density); - bool full_case = (min_choice == 0) && (max_choice == (1 << GetSize(sig))-1) && (max_choice+1 == GetSize(choices)); + if (full_pmux) { + int full_density = 100*GetSize(choices) / (1 << GetSize(sig)); + log(" full density: %d%%\n", full_density); + if (full_density < min_density) { + full_pmux = false; + } else { + min_choice = 0; + max_choice = (1 << GetSize(sig))-1; + log(" update to full case.\n"); + log(" new min choice: %d\n", min_choice); + log(" new max choice: %d\n", max_choice); + } + } + + bool full_case = (min_choice == 0) && (max_choice == (1 << GetSize(sig))-1) && (full_pmux || max_choice+1 == GetSize(choices)); log(" full case: %s\n", full_case ? "true" : "false"); // check density percentages @@ -677,6 +694,10 @@ struct Pmux2ShiftxPass : public Pass { // create data signal SigSpec data(State::Sx, (max_choice+1)*extwidth); + if (full_pmux) { + for (int i = 0; i <= max_choice; i++) + data.replace(i*extwidth, A); + } for (auto &it : perm_choices) { int position = it.first.as_int()*extwidth; int data_index = it.second; |