diff --git a/kernel/satgen.h b/kernel/satgen.h
index ae155a2eb..3429f8239 100644
--- a/kernel/satgen.h
+++ b/kernel/satgen.h
@@ -23,6 +23,7 @@
 #include "kernel/rtlil.h"
 #include "kernel/sigtools.h"
 #include "kernel/celltypes.h"
+#include "kernel/macc.h"
 
 #include "libs/ezsat/ezminisat.h"
 typedef ezMiniSAT ezDefaultSAT;
@@ -762,6 +763,76 @@ struct SatGen
 			return true;
 		}
 
+		if (cell->type == "$macc")
+		{
+			std::vector<int> a = importDefSigSpec(cell->getPort("\\A"), timestep);
+			std::vector<int> b = importDefSigSpec(cell->getPort("\\B"), timestep);
+			std::vector<int> y = importDefSigSpec(cell->getPort("\\Y"), timestep);
+
+			Macc macc;
+			macc.from_cell(cell);
+
+			std::vector<int> tmp(SIZE(y), ez->FALSE);
+
+			for (auto &port : macc.ports)
+			{
+				std::vector<int> in_a = importDefSigSpec(port.in_a, timestep);
+				std::vector<int> in_b = importDefSigSpec(port.in_b, timestep);
+
+				while (SIZE(in_a) < SIZE(y))
+					in_a.push_back(port.is_signed && !in_a.empty() ? in_a.back() : ez->FALSE);
+				in_a.resize(SIZE(y));
+
+				if (SIZE(in_b))
+				{
+					while (SIZE(in_b) < SIZE(y))
+						in_b.push_back(port.is_signed && !in_b.empty() ? in_b.back() : ez->FALSE);
+					in_b.resize(SIZE(y));
+
+					for (int i = 0; i < SIZE(in_b); i++) {
+						std::vector<int> shifted_a(in_a.size(), ez->FALSE);
+						for (int j = i; j < int(in_a.size()); j++)
+							shifted_a.at(j) = in_a.at(j-i);
+						if (port.do_subtract)
+							tmp = ez->vec_ite(in_b.at(i), ez->vec_sub(tmp, shifted_a), tmp);
+						else
+							tmp = ez->vec_ite(in_b.at(i), ez->vec_add(tmp, shifted_a), tmp);
+					}
+				}
+				else
+				{
+					if (port.do_subtract)
+						tmp = ez->vec_sub(tmp, in_a);
+					else
+						tmp = ez->vec_add(tmp, in_a);
+				}
+			}
+
+			for (int i = 0; i < SIZE(b); i++) {
+				std::vector<int> val(SIZE(y), ez->FALSE);
+				val.at(0) = b.at(i);
+				tmp = ez->vec_add(tmp, val);
+			}
+
+			if (model_undef)
+			{
+				std::vector<int> undef_a = importUndefSigSpec(cell->getPort("\\A"), timestep);
+				std::vector<int> undef_b = importUndefSigSpec(cell->getPort("\\B"), timestep);
+
+				int undef_any_a = ez->expression(ezSAT::OpOr, undef_a);
+				int undef_any_b = ez->expression(ezSAT::OpOr, undef_b);
+
+				std::vector<int> undef_y = importUndefSigSpec(cell->getPort("\\Y"), timestep);
+				ez->assume(ez->vec_eq(undef_y, std::vector<int>(SIZE(y), ez->OR(undef_any_a, undef_any_b))));
+
+				undefGating(y, tmp, undef_y);
+			}
+			else
+				ez->assume(ez->vec_eq(y, tmp));
+
+			return true;
+		}
+
 		if (cell->type == "$div" || cell->type == "$mod")
 		{
 			std::vector<int> a = importDefSigSpec(cell->getPort("\\A"), timestep);
diff --git a/passes/tests/test_cell.cc b/passes/tests/test_cell.cc
index 96f08de4b..edab51eb2 100644
--- a/passes/tests/test_cell.cc
+++ b/passes/tests/test_cell.cc
@@ -42,9 +42,9 @@ static void create_gold_module(RTLIL::Design *design, RTLIL::IdString cell_type,
 	if (cell_type == "$macc")
 	{
 		Macc macc;
-		int width = 1 + xorshift32(16);
+		int width = 1 + xorshift32(8);
 		int depth = 1 + xorshift32(6);
-		int mulbits = 0;
+		int mulbits_a = 0, mulbits_b = 0;
 
 		RTLIL::Wire *wire_a = module->addWire("\\A");
 		wire_a->width = 0;
@@ -55,10 +55,11 @@ static void create_gold_module(RTLIL::Design *design, RTLIL::IdString cell_type,
 			int size_a = xorshift32(width) + 1;
 			int size_b = xorshift32(width) + 1;
 
-			if (mulbits + size_a*size_b > 256 || xorshift32(2) == 1)
+			if (mulbits_a + size_a*size_b <= 96 && mulbits_b + size_a + size_b <= 16 && xorshift32(2) == 1) {
+				mulbits_a += size_a * size_b;
+				mulbits_b += size_a + size_b;
+			} else
 				size_b = 0;
-			else
-				mulbits += size_a*size_b;
 
 			Macc::port_t this_port;
 
diff --git a/techlibs/common/simlib.v b/techlibs/common/simlib.v
index eabd65951..b1f871d9b 100644
--- a/techlibs/common/simlib.v
+++ b/techlibs/common/simlib.v
@@ -771,16 +771,16 @@ module \$macc (A, B, Y);
 	localparam integer num_abits = $clog2(A_WIDTH);
 
 	function [2*num_ports*num_abits-1:0] get_port_offsets;
-		input [CONFIG_WIDTH-1:0] CONFIG;
+		input [CONFIG_WIDTH-1:0] cfg;
 		integer i, cursor;
 		begin
 			cursor = 0;
 			get_port_offsets = 0;
 			for (i = 0; i < num_ports; i = i+1) begin
 				get_port_offsets[(2*i + 0)*num_abits +: num_abits] = cursor;
-				cursor = cursor + CONFIG[4 + i*(2 + 2*num_bits) + 2 +: num_bits];
+				cursor = cursor + cfg[4 + i*(2 + 2*num_bits) + 2 +: num_bits];
 				get_port_offsets[(2*i + 1)*num_abits +: num_abits] = cursor;
-				cursor = cursor + CONFIG[4 + i*(2 + 2*num_bits) + 2 + num_bits +: num_bits];
+				cursor = cursor + cfg[4 + i*(2 + 2*num_bits) + 2 + num_bits +: num_bits];
 			end
 		end
 	endfunction
diff --git a/techlibs/common/techmap.v b/techlibs/common/techmap.v
index 8237a7372..f0397858f 100644
--- a/techlibs/common/techmap.v
+++ b/techlibs/common/techmap.v
@@ -597,16 +597,16 @@ module \$macc (A, B, Y);
 	localparam integer num_abits = $clog2(A_WIDTH);
 
 	function [2*num_ports*num_abits-1:0] get_port_offsets;
-		input [CONFIG_WIDTH-1:0] CONFIG;
+		input [CONFIG_WIDTH-1:0] cfg;
 		integer i, cursor;
 		begin
 			cursor = 0;
 			get_port_offsets = 0;
 			for (i = 0; i < num_ports; i = i+1) begin
 				get_port_offsets[(2*i + 0)*num_abits +: num_abits] = cursor;
-				cursor = cursor + CONFIG[4 + i*(2 + 2*num_bits) + 2 +: num_bits];
+				cursor = cursor + cfg[4 + i*(2 + 2*num_bits) + 2 +: num_bits];
 				get_port_offsets[(2*i + 1)*num_abits +: num_abits] = cursor;
-				cursor = cursor + CONFIG[4 + i*(2 + 2*num_bits) + 2 + num_bits +: num_bits];
+				cursor = cursor + cfg[4 + i*(2 + 2*num_bits) + 2 + num_bits +: num_bits];
 			end
 		end
 	endfunction