diff options
Diffstat (limited to 'passes/proc')
| -rw-r--r-- | passes/proc/proc_mux.cc | 27 |
1 files changed, 17 insertions, 10 deletions
diff --git a/passes/proc/proc_mux.cc b/passes/proc/proc_mux.cc index 7cac0327b..7d3d23408 100644 --- a/passes/proc/proc_mux.cc +++ b/passes/proc/proc_mux.cc @@ -340,7 +340,7 @@ RTLIL::SigSpec signal_to_mux_tree(RTLIL::Module *mod, SnippetSwCache &swcache, d // evaluate in reverse order to give the first entry the top priority RTLIL::SigSpec initial_val = result; RTLIL::Cell *last_mux_cell = NULL; - bool shiftx = true; + bool shiftx = initial_val.is_fully_undef(); for (size_t i = 0; i < sw->cases.size(); i++) { int case_idx = sw->cases.size() - i - 1; RTLIL::CaseRule *cs2 = sw->cases[case_idx]; @@ -355,20 +355,27 @@ RTLIL::SigSpec signal_to_mux_tree(RTLIL::Module *mod, SnippetSwCache &swcache, d // Keep checking if case condition is the same as the current case index if (cs2->compare.size() == 1 && cs2->compare.front().is_fully_const()) shiftx = (cs2->compare.front().as_int() == case_idx); + else + shiftx = false; } } - // Transform into a $shiftx if possible + // Transform into a $shiftx where possible if (shiftx && last_mux_cell->type == "$pmux") { - // Sanity check that A port of $pmux should be 'bx - log_assert(last_mux_cell->getPort("\\A").is_fully_undef()); - // Because we went in reverse order above, un-reverse its B port here - auto b_port = last_mux_cell->getPort("\\B").chunks(); - std::reverse(b_port.begin(), b_port.end()); - // Create a $shiftx that shifts by the address line used in the case statement - mod->addShiftx(NEW_ID, b_port, sw->signal, last_mux_cell->getPort("\\Y")); + // Create bit-blasted $shiftx-es that shifts by the address line used in the case statement + auto pmux_b_port = last_mux_cell->getPort("\\B"); + auto pmux_y_port = last_mux_cell->getPort("\\Y"); + int width = last_mux_cell->getParam("\\WIDTH").as_int(); + for (int i = 0; i < width; ++i) { + RTLIL::SigSpec a_port; + // Because we went in reverse order above, un-reverse $pmux's B port here + for (int j = pmux_b_port.size()/width-1; j >= 0; --j) + a_port.append(pmux_b_port.extract(j*width+i, 1)); + // Create a $shiftx that shifts by the address line used in the case statement + mod->addShiftx(NEW_ID, a_port, sw->signal, pmux_y_port.extract(i, 1)); + } // Disconnect $pmux by replacing its output port with a floating wire - last_mux_cell->setPort("\\Y", mod->addWire(NEW_ID, last_mux_cell->getParam("\\WIDTH").as_int())); + last_mux_cell->setPort("\\Y", mod->addWire(NEW_ID, width)); } } |