7 files changed, 47 insertions, 10 deletions
diff --git a/backends/aiger/xaiger.cc b/backends/aiger/xaiger.cc
index 69f63486c..a3a753912 100644
--- a/backends/aiger/xaiger.cc
+++ b/backends/aiger/xaiger.cc
@@ -53,7 +53,7 @@ PRIVATE_NAMESPACE_BEGIN
 
 inline int32_t to_big_endian(int32_t i32) {
 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
-	return __builtin_bswap32(i32);
+	return bswap32(i32);
 #elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
 	return i32;
 #else
@@ -610,15 +610,15 @@ struct XAigerWriter
 			std::stringstream h_buffer;
 			auto write_h_buffer = std::bind(write_buffer, std::ref(h_buffer), std::placeholders::_1);
 			write_h_buffer(1);
-			log_debug("ciNum = %zu\n", input_bits.size() + ci_bits.size());
+			log_debug("ciNum = %d\n", GetSize(input_bits) + GetSize(ci_bits));
 			write_h_buffer(input_bits.size() + ci_bits.size());
-			log_debug("coNum = %zu\n", output_bits.size() + co_bits.size());
+			log_debug("coNum = %d\n", GetSize(output_bits) + GetSize(co_bits));
 			write_h_buffer(output_bits.size() + co_bits.size());
-			log_debug("piNum = %zu\n", input_bits.size());
+			log_debug("piNum = %d\n", GetSize(input_bits));
 			write_h_buffer(input_bits.size());
-			log_debug("poNum = %zu\n", output_bits.size());
+			log_debug("poNum = %d\n", GetSize(output_bits));
 			write_h_buffer(output_bits.size());
-			log_debug("boxNum = %zu\n", box_list.size());
+			log_debug("boxNum = %d\n", GetSize(box_list));
 			write_h_buffer(box_list.size());
 
 			RTLIL::Module *holes_module = nullptr;
@@ -772,7 +772,7 @@ struct XAigerWriter
 
 				if (output_bits.count(b)) {
 					int o = ordered_outputs.at(b);
-					output_lines[o] += stringf("output %lu %d %s\n", o - co_bits.size(), i, log_id(wire));
+					output_lines[o] += stringf("output %d %d %s\n", o - GetSize(co_bits), i, log_id(wire));
 					continue;
 				}
 
diff --git a/backends/blif/blif.cc b/backends/blif/blif.cc
index a1761b662..f32b0f533 100644
--- a/backends/blif/blif.cc
+++ b/backends/blif/blif.cc
@@ -327,6 +327,13 @@ struct BlifDumper
 				goto internal_cell;
 			}
 
+			if (!config->icells_mode && cell->type == "$_NMUX_") {
+				f << stringf(".names %s %s %s %s\n0-0 1\n-01 1\n",
+						cstr(cell->getPort("\\A")), cstr(cell->getPort("\\B")),
+						cstr(cell->getPort("\\S")), cstr(cell->getPort("\\Y")));
+				goto internal_cell;
+			}
+
 			if (!config->icells_mode && cell->type == "$_FF_") {
 				f << stringf(".latch %s %s%s\n", cstr(cell->getPort("\\D")), cstr(cell->getPort("\\Q")),
 						cstr_init(cell->getPort("\\Q")));
diff --git a/backends/btor/btor.cc b/backends/btor/btor.cc
index a507b120b..7bacce2af 100644
--- a/backends/btor/btor.cc
+++ b/backends/btor/btor.cc
@@ -496,7 +496,7 @@ struct BtorWorker
 			goto okay;
 		}
 
-		if (cell->type.in("$mux", "$_MUX_"))
+		if (cell->type.in("$mux", "$_MUX_", "$_NMUX_"))
 		{
 			SigSpec sig_a = sigmap(cell->getPort("\\A"));
 			SigSpec sig_b = sigmap(cell->getPort("\\B"));
@@ -511,6 +511,12 @@ struct BtorWorker
 			int nid = next_nid++;
 			btorf("%d ite %d %d %d %d\n", nid, sid, nid_s, nid_b, nid_a);
 
+			if (cell->type == "$_NMUX_") {
+				int tmp = nid;
+				nid = next_nid++;
+				btorf("%d not %d %d\n", nid, sid, tmp);
+			}
+
 			add_nid_sig(nid, sig_y);
 			goto okay;
 		}
diff --git a/backends/simplec/simplec.cc b/backends/simplec/simplec.cc
index 6f2ccbe20..54dbb84af 100644
--- a/backends/simplec/simplec.cc
+++ b/backends/simplec/simplec.cc
@@ -472,7 +472,7 @@ struct SimplecWorker
 			return;
 		}
 
-		if (cell->type == "$_MUX_")
+		if (cell->type.in("$_MUX_", "$_NMUX_"))
 		{
 			SigBit a = sigmaps.at(work->module)(cell->getPort("\\A"));
 			SigBit b = sigmaps.at(work->module)(cell->getPort("\\B"));
@@ -484,7 +484,9 @@ struct SimplecWorker
 			string s_expr = s.wire ? util_get_bit(work->prefix + cid(s.wire->name), s.wire->width, s.offset) : s.data ? "1" : "0";
 
 			// casts to bool are a workaround for CBMC bug (https://github.com/diffblue/cbmc/issues/933)
-			string expr = stringf("%s ? (bool)%s : (bool)%s", s_expr.c_str(), b_expr.c_str(), a_expr.c_str());
+			string expr = stringf("%s ? %s(bool)%s : %s(bool)%s", s_expr.c_str(),
+					cell->type == "$_NMUX_" ? "!" : "", b_expr.c_str(),
+					cell->type == "$_NMUX_" ? "!" : "", a_expr.c_str());
 
 			log_assert(y.wire);
 			funct_declarations.push_back(util_set_bit(work->prefix + cid(y.wire->name), y.wire->width, y.offset, expr) +
diff --git a/backends/smt2/smt2.cc b/backends/smt2/smt2.cc
index e318a4051..ddd680782 100644
--- a/backends/smt2/smt2.cc
+++ b/backends/smt2/smt2.cc
@@ -510,6 +510,7 @@ struct Smt2Worker
 		if (cell->type == "$_ANDNOT_") return export_gate(cell, "(and A (not B))");
 		if (cell->type == "$_ORNOT_") return export_gate(cell, "(or A (not B))");
 		if (cell->type == "$_MUX_") return export_gate(cell, "(ite S B A)");
+		if (cell->type == "$_NMUX_") return export_gate(cell, "(not (ite S B A))");
 		if (cell->type == "$_AOI3_") return export_gate(cell, "(not (or (and A B) C))");
 		if (cell->type == "$_OAI3_") return export_gate(cell, "(not (and (or A B) C))");
 		if (cell->type == "$_AOI4_") return export_gate(cell, "(not (or (and A B) (and C D)))");
diff --git a/backends/smv/smv.cc b/backends/smv/smv.cc
index d75456c1b..e9586fae0 100644
--- a/backends/smv/smv.cc
+++ b/backends/smv/smv.cc
@@ -537,6 +537,13 @@ struct SmvWorker
 				continue;
 			}
 
+			if (cell->type == "$_NMUX_")
+			{
+				definitions.push_back(stringf("%s := !(bool(%s) ? %s : %s);", lvalue(cell->getPort("\\Y")),
+						rvalue(cell->getPort("\\S")), rvalue(cell->getPort("\\B")), rvalue(cell->getPort("\\A"))));
+				continue;
+			}
+
 			if (cell->type == "$_AOI3_")
 			{
 				definitions.push_back(stringf("%s := !((%s & %s) | %s);", lvalue(cell->getPort("\\Y")),
diff --git a/backends/verilog/verilog_backend.cc b/backends/verilog/verilog_backend.cc
index e0b3a6f80..776f4eacb 100644
--- a/backends/verilog/verilog_backend.cc
+++ b/backends/verilog/verilog_backend.cc
@@ -558,6 +558,20 @@ bool dump_cell_expr(std::ostream &f, std::string indent, RTLIL::Cell *cell)
 		return true;
 	}
 
+	if (cell->type == "$_NMUX_") {
+		f << stringf("%s" "assign ", indent.c_str());
+		dump_sigspec(f, cell->getPort("\\Y"));
+		f << stringf(" = !(");
+		dump_cell_expr_port(f, cell, "S", false);
+		f << stringf(" ? ");
+		dump_attributes(f, "", cell->attributes, ' ');
+		dump_cell_expr_port(f, cell, "B", false);
+		f << stringf(" : ");
+		dump_cell_expr_port(f, cell, "A", false);
+		f << stringf(");\n");
+		return true;
+	}
+
 	if (cell->type.in("$_AOI3_", "$_OAI3_")) {
 		f << stringf("%s" "assign ", indent.c_str());
 		dump_sigspec(f, cell->getPort("\\Y"));