diff --git a/techlibs/xilinx/cells_sim.v b/techlibs/xilinx/cells_sim.v
index 22dca3c47..eb145593e 100644
--- a/techlibs/xilinx/cells_sim.v
+++ b/techlibs/xilinx/cells_sim.v
@@ -2155,7 +2155,235 @@ assign PCOUT = P;
 
 endmodule
 
-// TODO: DSP48 (Virtex 4).
+module DSP48 (
+    input signed [17:0] A,
+    input signed [17:0] B,
+    input signed [47:0] C,
+    input signed [17:0] BCIN,
+    input signed [47:0] PCIN,
+    input CARRYIN,
+    input [6:0] OPMODE,
+    input SUBTRACT,
+    input [1:0] CARRYINSEL,
+    output signed [47:0] P,
+    output signed [17:0] BCOUT,
+    output signed [47:0] PCOUT,
+    (* clkbuf_sink *)
+    input CLK,
+    input CEA,
+    input CEB,
+    input CEC,
+    input CEM,
+    input CECARRYIN,
+    input CECINSUB,
+    input CECTRL,
+    input CEP,
+    input RSTA,
+    input RSTB,
+    input RSTC,
+    input RSTM,
+    input RSTCARRYIN,
+    input RSTCTRL,
+    input RSTP
+);
+
+parameter integer AREG = 1;
+parameter integer BREG = 1;
+parameter integer CREG = 1;
+parameter integer MREG = 1;
+parameter integer PREG = 1;
+parameter integer CARRYINREG = 1;
+parameter integer CARRYINSELREG = 1;
+parameter integer OPMODEREG = 1;
+parameter integer SUBTRACTREG = 1;
+parameter B_INPUT = "DIRECT";
+parameter LEGACY_MODE = "MULT18X18S";
+
+wire signed [17:0] A_OUT;
+wire signed [17:0] B_OUT;
+wire signed [47:0] C_OUT;
+wire signed [35:0] M_MULT;
+wire signed [35:0] M_OUT;
+wire signed [47:0] P_IN;
+wire [6:0] OPMODE_OUT;
+wire [1:0] CARRYINSEL_OUT;
+wire CARRYIN_OUT;
+wire SUBTRACT_OUT;
+reg INT_CARRYIN_XY;
+reg INT_CARRYIN_Z;
+reg signed [47:0] XMUX;
+reg signed [47:0] YMUX;
+wire signed [47:0] XYMUX;
+reg signed [47:0] ZMUX;
+reg CIN;
+
+// The B input multiplexer.
+wire signed [17:0] B_MUX;
+assign B_MUX = (B_INPUT == "DIRECT") ? B : BCIN;
+
+// The cascade output.
+assign BCOUT = B_OUT;
+assign PCOUT = P;
+
+// The registers.
+reg signed [17:0] A0_REG;
+reg signed [17:0] A1_REG;
+reg signed [17:0] B0_REG;
+reg signed [17:0] B1_REG;
+reg signed [47:0] C_REG;
+reg signed [35:0] M_REG;
+reg signed [47:0] P_REG;
+reg [6:0] OPMODE_REG;
+reg [1:0] CARRYINSEL_REG;
+reg SUBTRACT_REG;
+reg CARRYIN_REG;
+reg INT_CARRYIN_XY_REG;
+
+initial begin
+	A0_REG = 0;
+	A1_REG = 0;
+	B0_REG = 0;
+	B1_REG = 0;
+	C_REG = 0;
+	M_REG = 0;
+	P_REG = 0;
+	OPMODE_REG = 0;
+	CARRYINSEL_REG = 0;
+	SUBTRACT_REG = 0;
+	CARRYIN_REG = 0;
+	INT_CARRYIN_XY_REG = 0;
+end
+
+always @(posedge CLK) begin
+	if (RSTA) begin
+		A0_REG <= 0;
+		A1_REG <= 0;
+	end else if (CEA) begin
+		A0_REG <= A;
+		A1_REG <= A0_REG;
+	end
+	if (RSTB) begin
+		B0_REG <= 0;
+		B1_REG <= 0;
+	end else if (CEB) begin
+		B0_REG <= B_MUX;
+		B1_REG <= B0_REG;
+	end
+	if (RSTC) begin
+		C_REG <= 0;
+	end else if (CEC) begin
+		C_REG <= C;
+	end
+	if (RSTM) begin
+		M_REG <= 0;
+	end else if (CEM) begin
+		M_REG <= M_MULT;
+	end
+	if (RSTP) begin
+		P_REG <= 0;
+	end else if (CEP) begin
+		P_REG <= P_IN;
+	end
+	if (RSTCTRL) begin
+		OPMODE_REG <= 0;
+		CARRYINSEL_REG <= 0;
+		SUBTRACT_REG <= 0;
+	end else begin
+		if (CECTRL) begin
+			OPMODE_REG <= OPMODE;
+			CARRYINSEL_REG <= CARRYINSEL;
+		end
+		if (CECINSUB)
+			SUBTRACT_REG <= SUBTRACT;
+	end
+	if (RSTCARRYIN) begin
+		CARRYIN_REG <= 0;
+		INT_CARRYIN_XY_REG <= 0;
+	end else begin
+		if (CECINSUB)
+			CARRYIN_REG <= CARRYIN;
+		if (CECARRYIN)
+			INT_CARRYIN_XY_REG <= INT_CARRYIN_XY;
+	end
+end
+
+// The register enables.
+assign A_OUT = (AREG == 2) ? A1_REG : (AREG == 1) ? A0_REG : A;
+assign B_OUT = (BREG == 2) ? B1_REG : (BREG == 1) ? B0_REG : B_MUX;
+assign C_OUT = (CREG == 1) ? C_REG : C;
+assign M_OUT = (MREG == 1) ? M_REG : M_MULT;
+assign P = (PREG == 1) ? P_REG : P_IN;
+assign OPMODE_OUT = (OPMODEREG == 1) ? OPMODE_REG : OPMODE;
+assign SUBTRACT_OUT = (SUBTRACTREG == 1) ? SUBTRACT_REG : SUBTRACT;
+assign CARRYINSEL_OUT = (CARRYINSELREG == 1) ? CARRYINSEL_REG : CARRYINSEL;
+assign CARRYIN_OUT = (CARRYINREG == 1) ? CARRYIN_REG : CARRYIN;
+
+// The multiplier.
+assign M_MULT = A_OUT * B_OUT;
+
+// The post-adder inputs.
+always @* begin
+	case (OPMODE_OUT[1:0])
+		2'b00: XMUX <= 0;
+		2'b10: XMUX <= P;
+		2'b11: XMUX <= {{12{A_OUT[17]}}, A_OUT, B_OUT};
+		default: XMUX <= 48'hxxxxxxxxxxxx;
+	endcase
+	case (OPMODE_OUT[1:0])
+		2'b01: INT_CARRYIN_XY <= A_OUT[17] ~^ B_OUT[17];
+		2'b11: INT_CARRYIN_XY <= ~A_OUT[17];
+		// TODO: not tested in hardware.
+		default: INT_CARRYIN_XY <= A_OUT[17] ~^ B_OUT[17];
+	endcase
+end
+
+always @* begin
+	case (OPMODE_OUT[3:2])
+		2'b00: YMUX <= 0;
+		2'b11: YMUX <= C_OUT;
+		default: YMUX <= 48'hxxxxxxxxxxxx;
+	endcase
+end
+
+assign XYMUX = (OPMODE_OUT[3:0] == 4'b0101) ? M_OUT : (XMUX + YMUX);
+
+always @* begin
+	case (OPMODE_OUT[6:4])
+		3'b000: ZMUX <= 0;
+		3'b001: ZMUX <= PCIN;
+		3'b010: ZMUX <= P;
+		3'b011: ZMUX <= C_OUT;
+		3'b101: ZMUX <= {{17{PCIN[47]}}, PCIN[47:17]};
+		3'b110: ZMUX <= {{17{P[47]}}, P[47:17]};
+		default: ZMUX <= 48'hxxxxxxxxxxxx;
+	endcase
+	// TODO: check how all this works on actual hw.
+	if (OPMODE_OUT[1:0] == 2'b10)
+		INT_CARRYIN_Z <= ~P[47];
+	else
+		case (OPMODE_OUT[6:4])
+			3'b001: INT_CARRYIN_Z <= ~PCIN[47];
+			3'b010: INT_CARRYIN_Z <= ~P[47];
+			3'b101: INT_CARRYIN_Z <= ~PCIN[47];
+			3'b110: INT_CARRYIN_Z <= ~P[47];
+			default: INT_CARRYIN_Z <= 1'bx;
+		endcase
+end
+
+always @* begin
+	case (CARRYINSEL_OUT)
+		2'b00: CIN <= CARRYIN_OUT;
+		2'b01: CIN <= INT_CARRYIN_Z;
+		2'b10: CIN <= INT_CARRYIN_XY;
+		2'b11: CIN <= INT_CARRYIN_XY_REG;
+		default: CIN <= 1'bx;
+	endcase
+end
+
+// The post-adder.
+assign P_IN = SUBTRACT_OUT ? (ZMUX - (XYMUX + CIN)) : (ZMUX + XYMUX + CIN);
+
+endmodule
 
 // TODO: DSP48E (Virtex 5).
 
diff --git a/techlibs/xilinx/cells_xtra.py b/techlibs/xilinx/cells_xtra.py
index d5c58c5d7..06e982a0e 100644
--- a/techlibs/xilinx/cells_xtra.py
+++ b/techlibs/xilinx/cells_xtra.py
@@ -209,7 +209,7 @@ CELLS = [
     # Cell('MULT18X18SIO', port_attrs={'CLK': ['clkbuf_sink']}), # Spartan 3E
     # Cell('DSP48A', port_attrs={'CLK': ['clkbuf_sink']}), # Spartan 3A DSP
     # Cell('DSP48A1', port_attrs={'CLK': ['clkbuf_sink']}), # Spartan 6
-    Cell('DSP48', port_attrs={'CLK': ['clkbuf_sink']}), # Virtex 4
+    # Cell('DSP48', port_attrs={'CLK': ['clkbuf_sink']}), # Virtex 4
     Cell('DSP48E', port_attrs={'CLK': ['clkbuf_sink']}), # Virtex 5
     #Cell('DSP48E1', port_attrs={'CLK': ['clkbuf_sink']}), # Virtex 6 / Series 7
     Cell('DSP48E2', port_attrs={'CLK': ['clkbuf_sink']}), # Ultrascale
diff --git a/techlibs/xilinx/cells_xtra.v b/techlibs/xilinx/cells_xtra.v
index c3e5c72f9..54e48f1a6 100644
--- a/techlibs/xilinx/cells_xtra.v
+++ b/techlibs/xilinx/cells_xtra.v
@@ -5476,49 +5476,6 @@ module URAM288_BASE (...);
     input SLEEP;
 endmodule
 
-module DSP48 (...);
-    parameter integer AREG = 1;
-    parameter integer BREG = 1;
-    parameter B_INPUT = "DIRECT";
-    parameter integer CARRYINREG = 1;
-    parameter integer CARRYINSELREG = 1;
-    parameter integer CREG = 1;
-    parameter LEGACY_MODE = "MULT18X18S";
-    parameter integer MREG = 1;
-    parameter integer OPMODEREG = 1;
-    parameter integer PREG = 1;
-    parameter integer SUBTRACTREG = 1;
-    output [17:0] BCOUT;
-    output [47:0] P;
-    output [47:0] PCOUT;
-    input [17:0] A;
-    input [17:0] B;
-    input [17:0] BCIN;
-    input [47:0] C;
-    input CARRYIN;
-    input [1:0] CARRYINSEL;
-    input CEA;
-    input CEB;
-    input CEC;
-    input CECARRYIN;
-    input CECINSUB;
-    input CECTRL;
-    input CEM;
-    input CEP;
-    (* clkbuf_sink *)
-    input CLK;
-    input [6:0] OPMODE;
-    input [47:0] PCIN;
-    input RSTA;
-    input RSTB;
-    input RSTC;
-    input RSTCARRYIN;
-    input RSTCTRL;
-    input RSTM;
-    input RSTP;
-    input SUBTRACT;
-endmodule
-
 module DSP48E (...);
     parameter SIM_MODE = "SAFE";
     parameter integer ACASCREG = 1;
diff --git a/techlibs/xilinx/tests/.gitignore b/techlibs/xilinx/tests/.gitignore
index 848f88d53..0d9c28fde 100644
--- a/techlibs/xilinx/tests/.gitignore
+++ b/techlibs/xilinx/tests/.gitignore
@@ -12,4 +12,7 @@ test_dsp48a_model_ref.v
 test_dsp48a1_model_ref.v
 test_dsp48a1_model_uut.v
 test_dsp48a1_model
+test_dsp48_model_ref.v
+test_dsp48_model_uut.v
+test_dsp48_model
 *.vcd
diff --git a/techlibs/xilinx/tests/test_dsp48_model.sh b/techlibs/xilinx/tests/test_dsp48_model.sh
new file mode 100644
index 000000000..9a73f9b0c
--- /dev/null
+++ b/techlibs/xilinx/tests/test_dsp48_model.sh
@@ -0,0 +1,14 @@
+#!/bin/bash
+set -ex
+if [ -z $ISE_DIR ]; then
+	ISE_DIR=/opt/Xilinx/ISE/14.7
+fi
+sed 's/DSP48 /DSP48_UUT /; /DSP48_UUT/,/endmodule/ p; d;' < ../cells_sim.v > test_dsp48_model_uut.v
+if [ ! -f "test_dsp48_model_ref.v" ]; then
+	cp $ISE_DIR/ISE_DS/ISE/verilog/src/unisims/DSP48.v test_dsp48_model_ref.v
+fi
+for tb in mult_allreg mult_noreg mult_inreg
+do
+	iverilog -s $tb -s glbl -o test_dsp48_model test_dsp48_model.v test_dsp48_model_uut.v test_dsp48_model_ref.v $ISE_DIR/ISE_DS/ISE/verilog/src/glbl.v
+	vvp -N ./test_dsp48_model
+done
diff --git a/techlibs/xilinx/tests/test_dsp48_model.v b/techlibs/xilinx/tests/test_dsp48_model.v
new file mode 100644
index 000000000..d69c00e93
--- /dev/null
+++ b/techlibs/xilinx/tests/test_dsp48_model.v
@@ -0,0 +1,287 @@
+`timescale 1ns / 1ps
+
+module testbench;
+	parameter integer AREG = 1;
+	parameter integer BREG = 1;
+	parameter integer CREG = 1;
+	parameter integer MREG = 1;
+	parameter integer PREG = 1;
+	parameter integer CARRYINREG = 1;
+	parameter integer CARRYINSELREG = 1;
+	parameter integer OPMODEREG = 1;
+	parameter integer SUBTRACTREG = 1;
+	parameter B_INPUT = "DIRECT";
+	parameter LEGACY_MODE = "NONE";
+
+	reg CLK;
+	reg CEA, CEB, CEC, CEM, CEP, CECARRYIN, CECINSUB, CECTRL;
+	reg RSTA, RSTB, RSTC, RSTM, RSTP, RSTCARRYIN, RSTCTRL;
+	reg [17:0] A;
+	reg [17:0] B;
+	reg [47:0] C;
+	reg [17:0] BCIN;
+	reg [47:0] PCIN;
+	reg CARRYIN;
+	reg [6:0] OPMODE;
+	reg SUBTRACT;
+	reg [1:0] CARRYINSEL;
+
+	output [47:0] P, REF_P;
+	output [17:0] BCOUT, REF_BCOUT;
+	output [47:0] PCOUT, REF_PCOUT;
+
+	integer errcount = 0;
+
+	reg ERROR_FLAG = 0;
+
+	task clkcycle;
+		begin
+			#5;
+			CLK = ~CLK;
+			#10;
+			CLK = ~CLK;
+			#2;
+			ERROR_FLAG = 0;
+			if (REF_BCOUT !== BCOUT) begin
+				$display("ERROR at %1t: REF_BCOUT=%b UUT_BCOUT=%b DIFF=%b", $time, REF_BCOUT, BCOUT, REF_BCOUT ^ BCOUT);
+				errcount = errcount + 1;
+				ERROR_FLAG = 1;
+			end
+			if (REF_P !== P) begin
+				$display("ERROR at %1t: REF_P=%b UUT_P=%b DIFF=%b", $time, REF_P, P, REF_P ^ P);
+				errcount = errcount + 1;
+				ERROR_FLAG = 1;
+			end
+			if (REF_PCOUT !== PCOUT) begin
+				$display("ERROR at %1t: REF_PCOUT=%b UUT_PCOUT=%b DIFF=%b", $time, REF_PCOUT, PCOUT, REF_PCOUT ^ PCOUT);
+				errcount = errcount + 1;
+				ERROR_FLAG = 1;
+			end
+			#3;
+		end
+	endtask
+
+	reg config_valid = 0;
+	task drc;
+		begin
+			config_valid = 1;
+
+			if (OPMODE[1:0] == 2'b10 && PREG != 1) config_valid = 0;
+			if (OPMODE[1:0] == 2'b00 && CARRYINSEL == 2'b10) config_valid = 0;
+			if (OPMODE[1:0] == 2'b10 && CARRYINSEL == 2'b10) config_valid = 0;
+			if (OPMODE[1:0] == 2'b00 && CARRYINSEL == 2'b11) config_valid = 0;
+			if (OPMODE[1:0] == 2'b10 && CARRYINSEL == 2'b11) config_valid = 0;
+			if (OPMODE[3:2] == 2'b10) config_valid = 0;
+			if ((OPMODE[3:2] == 2'b01) ^ (OPMODE[1:0] == 2'b01) == 1'b1) config_valid = 0;
+			if ((OPMODE[6:4] == 3'b010 || OPMODE[6:4] == 3'b110) && PREG != 1) config_valid = 0;
+			if (OPMODE[6:4] == 3'b100) config_valid = 0;
+			if (OPMODE[6:4] == 3'b111) config_valid = 0;
+			if (OPMODE[6:4] == 3'b000 && CARRYINSEL == 2'b01) config_valid = 0;
+			if (OPMODE[6:4] == 3'b011 && CARRYINSEL == 2'b01) config_valid = 0;
+
+			// Xilinx models consider these combinations invalid for an unknown reason.
+			if (CARRYINSEL == 2'b01 && OPMODE[3:2] == 2'b00) config_valid = 0;
+			if (CARRYINSEL == 2'b10 && OPMODE == 7'b0000011) config_valid = 0;
+			if (CARRYINSEL == 2'b10 && OPMODE == 7'b0000101) config_valid = 0;
+			if (CARRYINSEL == 2'b10 && OPMODE == 7'b0100011) config_valid = 0;
+			if (CARRYINSEL == 2'b10 && OPMODE == 7'b0111111) config_valid = 0;
+			if (CARRYINSEL == 2'b10 && OPMODE == 7'b1100011) config_valid = 0;
+			if (CARRYINSEL == 2'b11 && OPMODE == 7'b0000011) config_valid = 0;
+			if (CARRYINSEL == 2'b11 && OPMODE == 7'b0000101) config_valid = 0;
+			if (CARRYINSEL == 2'b11 && OPMODE == 7'b0011111) config_valid = 0;
+			if (CARRYINSEL == 2'b11 && OPMODE == 7'b0010011) config_valid = 0;
+			if (CARRYINSEL == 2'b11 && OPMODE == 7'b0100011) config_valid = 0;
+			if (CARRYINSEL == 2'b11 && OPMODE == 7'b0100101) config_valid = 0;
+			if (CARRYINSEL == 2'b11 && OPMODE == 7'b0101111) config_valid = 0;
+			if (CARRYINSEL == 2'b11 && OPMODE == 7'b0110011) config_valid = 0;
+			if (CARRYINSEL == 2'b11 && OPMODE == 7'b0111111) config_valid = 0;
+			if (CARRYINSEL == 2'b11 && OPMODE == 7'b1010011) config_valid = 0;
+			if (CARRYINSEL == 2'b11 && OPMODE == 7'b1011111) config_valid = 0;
+			if (CARRYINSEL == 2'b11 && OPMODE == 7'b1100011) config_valid = 0;
+			if (CARRYINSEL == 2'b11 && OPMODE == 7'b1100101) config_valid = 0;
+			if (CARRYINSEL == 2'b11 && OPMODE == 7'b1101111) config_valid = 0;
+
+			if (CARRYINSEL == 2'b10 && OPMODE[3:0] == 4'b0101 && MREG == 1) config_valid = 0;
+			if (CARRYINSEL == 2'b11 && OPMODE[3:0] == 4'b0101 && MREG == 0) config_valid = 0;
+		end
+	endtask
+
+	initial begin
+		$dumpfile("test_dsp48_model.vcd");
+		$dumpvars(0, testbench);
+
+		#2;
+		CLK = 1'b0;
+		{CEA, CEB, CEC, CEM, CEP, CECARRYIN, CECINSUB, CECTRL} = 8'b11111111;
+		{A, B, C, PCIN, OPMODE, SUBTRACT, CARRYIN, CARRYINSEL} = 0;
+		{RSTA, RSTB, RSTC, RSTM, RSTP, RSTCARRYIN, RSTCTRL} = 7'b1111111;
+		repeat (10) begin
+			#10;
+			CLK = 1'b1;
+			#10;
+			CLK = 1'b0;
+			#10;
+			CLK = 1'b1;
+			#10;
+			CLK = 1'b0;
+		end
+		{RSTA, RSTB, RSTC, RSTM, RSTP, RSTCARRYIN, RSTCTRL} = 0;
+
+		repeat (100000) begin
+			clkcycle;
+			config_valid = 0;
+			while (!config_valid) begin
+				A = $urandom;
+				B = $urandom;
+				C = {$urandom, $urandom};
+				BCIN = $urandom;
+				PCIN = {$urandom, $urandom};
+
+				{CEA, CEB, CEC, CEM, CEP, CECARRYIN, CECINSUB, CECTRL} = $urandom | $urandom | $urandom;
+				{RSTA, RSTB, RSTC, RSTM, RSTP, RSTCARRYIN, RSTCTRL} = $urandom & $urandom & $urandom & $urandom & $urandom & $urandom;
+				{CARRYIN, CARRYINSEL, OPMODE, SUBTRACT} = $urandom;
+
+				drc;
+			end
+		end
+
+		if (errcount == 0) begin
+			$display("All tests passed.");
+			$finish;
+		end else begin
+			$display("Caught %1d errors.", errcount);
+			$stop;
+		end
+	end
+
+	DSP48 #(
+		.AREG               (AREG),
+		.BREG               (BREG),
+		.CREG               (CREG),
+		.MREG               (MREG),
+		.PREG               (PREG),
+		.CARRYINREG         (CARRYINREG),
+		.CARRYINSELREG      (CARRYINSELREG),
+		.OPMODEREG          (OPMODEREG),
+		.SUBTRACTREG        (SUBTRACTREG),
+		.B_INPUT            (B_INPUT),
+		.LEGACY_MODE        (LEGACY_MODE)
+	) ref (
+		.A             (A),
+		.B             (B),
+		.C             (C),
+		.BCIN          (BCIN),
+		.PCIN          (PCIN),
+		.CARRYIN       (CARRYIN),
+		.OPMODE        (OPMODE),
+		.SUBTRACT      (SUBTRACT),
+		.CARRYINSEL    (CARRYINSEL),
+		.BCOUT         (REF_BCOUT),
+		.P             (REF_P),
+		.PCOUT         (REF_PCOUT),
+		.CEA           (CEA),
+		.CEB           (CEB),
+		.CEC           (CEC),
+		.CEM           (CEM),
+		.CEP           (CEP),
+		.CECARRYIN     (CECARRYIN),
+		.CECINSUB       (CECINSUB),
+		.CECTRL        (CECTRL),
+		.CLK           (CLK),
+		.RSTA          (RSTA),
+		.RSTB          (RSTB),
+		.RSTC          (RSTC),
+		.RSTM          (RSTM),
+		.RSTP          (RSTP),
+		.RSTCARRYIN    (RSTCARRYIN),
+		.RSTCTRL       (RSTCTRL)
+	);
+
+	DSP48_UUT #(
+		.AREG               (AREG),
+		.BREG               (BREG),
+		.CREG               (CREG),
+		.MREG               (MREG),
+		.PREG               (PREG),
+		.CARRYINREG         (CARRYINREG),
+		.CARRYINSELREG      (CARRYINSELREG),
+		.OPMODEREG          (OPMODEREG),
+		.SUBTRACTREG        (SUBTRACTREG),
+		.B_INPUT            (B_INPUT),
+		.LEGACY_MODE        (LEGACY_MODE)
+	) uut (
+		.A             (A),
+		.B             (B),
+		.C             (C),
+		.BCIN          (BCIN),
+		.PCIN          (PCIN),
+		.CARRYIN       (CARRYIN),
+		.OPMODE        (OPMODE),
+		.SUBTRACT      (SUBTRACT),
+		.CARRYINSEL    (CARRYINSEL),
+		.BCOUT         (BCOUT),
+		.P             (P),
+		.PCOUT         (PCOUT),
+		.CEA           (CEA),
+		.CEB           (CEB),
+		.CEC           (CEC),
+		.CEM           (CEM),
+		.CEP           (CEP),
+		.CECARRYIN     (CECARRYIN),
+		.CECINSUB       (CECINSUB),
+		.CECTRL        (CECTRL),
+		.CLK           (CLK),
+		.RSTA          (RSTA),
+		.RSTB          (RSTB),
+		.RSTC          (RSTC),
+		.RSTM          (RSTM),
+		.RSTP          (RSTP),
+		.RSTCARRYIN    (RSTCARRYIN),
+		.RSTCTRL       (RSTCTRL)
+	);
+endmodule
+
+module mult_noreg;
+	testbench #(
+		.AREG               (0),
+		.BREG               (0),
+		.CREG               (0),
+		.MREG               (0),
+		.PREG               (0),
+		.CARRYINREG         (0),
+		.CARRYINSELREG      (0),
+		.OPMODEREG          (0),
+		.SUBTRACTREG        (0),
+		.B_INPUT            ("DIRECT")
+	) testbench ();
+endmodule
+
+module mult_allreg;
+	testbench #(
+		.AREG               (1),
+		.BREG               (1),
+		.CREG               (1),
+		.MREG               (1),
+		.PREG               (1),
+		.CARRYINREG         (1),
+		.CARRYINSELREG      (1),
+		.OPMODEREG          (1),
+		.SUBTRACTREG        (1),
+		.B_INPUT            ("CASCADE")
+	) testbench ();
+endmodule
+
+module mult_inreg;
+	testbench #(
+		.AREG               (1),
+		.BREG               (1),
+		.CREG               (1),
+		.MREG               (0),
+		.PREG               (0),
+		.CARRYINREG         (1),
+		.CARRYINSELREG      (0),
+		.OPMODEREG          (0),
+		.SUBTRACTREG        (0),
+		.B_INPUT            ("DIRECT")
+	) testbench ();
+endmodule