1 files changed, 16 insertions, 3 deletions

diff --git a/passes/techmap/simplemap.cc b/passes/techmap/simplemap.cc
index fbd86d591..e06a80bbd 100644
--- a/passes/techmap/simplemap.cc
+++ b/passes/techmap/simplemap.cc
@@ -60,16 +60,28 @@ static void simplemap_pos(RTLIL::Module *module, RTLIL::Cell *cell)
 	module->connections.push_back(RTLIL::SigSig(sig_y, sig_a));
 }
 
+static void simplemap_bu0(RTLIL::Module *module, RTLIL::Cell *cell)
+{
+	int width = cell->parameters.at("\\Y_WIDTH").as_int();
+
+	RTLIL::SigSpec sig_a = cell->connections.at("\\A");
+	sig_a.extend_u0(width, cell->parameters.at("\\A_SIGNED").as_bool());
+
+	RTLIL::SigSpec sig_y = cell->connections.at("\\Y");
+
+	module->connections.push_back(RTLIL::SigSig(sig_y, sig_a));
+}
+
 static void simplemap_bitop(RTLIL::Module *module, RTLIL::Cell *cell)
 {
 	int width = cell->parameters.at("\\Y_WIDTH").as_int();
 
 	RTLIL::SigSpec sig_a = cell->connections.at("\\A");
-	sig_a.extend(width, cell->parameters.at("\\A_SIGNED").as_bool());
+	sig_a.extend_u0(width, cell->parameters.at("\\A_SIGNED").as_bool());
 	sig_a.expand();
 
 	RTLIL::SigSpec sig_b = cell->connections.at("\\B");
-	sig_b.extend(width, cell->parameters.at("\\B_SIGNED").as_bool());
+	sig_b.extend_u0(width, cell->parameters.at("\\B_SIGNED").as_bool());
 	sig_b.expand();
 
 	RTLIL::SigSpec sig_y = cell->connections.at("\\Y");
@@ -454,6 +466,7 @@ void simplemap_get_mappers(std::map<std::string, void(*)(RTLIL::Module*, RTLIL::
 {
 	mappers["$not"]         = simplemap_not;
 	mappers["$pos"]         = simplemap_pos;
+	mappers["$bu0"]         = simplemap_bu0;
 	mappers["$and"]         = simplemap_bitop;
 	mappers["$or"]          = simplemap_bitop;
 	mappers["$xor"]         = simplemap_bitop;
@@ -485,7 +498,7 @@ struct SimplemapPass : public Pass {
 		log("This pass maps a small selection of simple coarse-grain cells to yosys gate\n");
 		log("primitives. The following internal cell types are mapped by this pass:\n");
 		log("\n");
-		log("  $not, $pos, $and, $or, $xor, $xnor\n");
+		log("  $not, $pos, $bu0, $and, $or, $xor, $xnor\n");
 		log("  $reduce_and, $reduce_or, $reduce_xor, $reduce_xnor, $reduce_bool\n");
 		log("  $logic_not, $logic_and, $logic_or, $mux\n");
 		log("  $sr, $dff, $dffsr, $adff, $dlatch\n");