Add mac.sh and macc_tb.v for testing

tests/xilinx/macc.sh

@@ -0,0 +1,3 @@
+../../yosys -qp "synth_xilinx -top macc2; rename -top macc2_uut" macc.v -o macc_uut.v
+iverilog -o test_macc macc_tb.v macc_uut.v macc.v ../../techlibs/xilinx/cells_sim.v
+vvp -N ./test_macc

tests/xilinx/macc_tb.v

@@ -0,0 +1,96 @@
+`timescale 1ns / 1ps
+
+module testbench;
+
+    parameter SIZEIN = 16, SIZEOUT = 40;
+	reg clk, ce, rst;
+   	reg signed [SIZEIN-1:0] a, b;
+	output signed [SIZEOUT-1:0] REF_accum_out, accum_out;
+	output REF_overflow, overflow;
+
+	integer errcount = 0;
+
+	reg ERROR_FLAG = 0;
+
+	task clkcycle;
+		begin
+			#5;
+			clk = ~clk;
+			#10;
+			clk = ~clk;
+			#2;
+			ERROR_FLAG = 0;
+			if (REF_accum_out !== accum_out) begin
+				$display("ERROR at %1t: REF_accum_out=%b UUT_accum_out=%b DIFF=%b", $time, REF_accum_out, accum_out, REF_accum_out ^ accum_out);
+				errcount = errcount + 1;
+				ERROR_FLAG = 1;
+			end
+			if (REF_overflow !== overflow) begin
+				$display("ERROR at %1t: REF_overflow=%b UUT_overflow=%b DIFF=%b", $time, REF_overflow, overflow, REF_overflow ^ overflow);
+				errcount = errcount + 1;
+				ERROR_FLAG = 1;
+			end
+			#3;
+		end
+	endtask
+
+	initial begin
+		//$dumpfile("test_macc.vcd");
+		//$dumpvars(0, testbench);
+
+		#2;
+		clk = 1'b0;
+        ce = 1'b0;
+        a = 0;
+        b = 0;
+
+        rst = 1'b1;
+		repeat (10) begin
+			#10;
+			clk = 1'b1;
+			#10;
+			clk = 1'b0;
+			#10;
+			clk = 1'b1;
+			#10;
+			clk = 1'b0;
+		end
+		rst = 1'b0;
+
+		repeat (10000) begin
+			clkcycle;
+            ce = 1; //$urandom & $urandom;
+			//rst = $urandom & $urandom & $urandom & $urandom & $urandom & $urandom;
+			a = $urandom & ~(1 << (SIZEIN-1));
+			b = $urandom & ~(1 << (SIZEIN-1));
+		end
+
+		if (errcount == 0) begin
+			$display("All tests passed.");
+			$finish;
+		end else begin
+			$display("Caught %1d errors.", errcount);
+			$stop;
+		end
+	end
+
+	macc2 ref (
+        .clk(clk),
+        .ce(ce),
+        .rst(rst),
+        .a(a),
+        .b(b),
+        .accum_out(REF_accum_out),
+        .overflow(REF_overflow)
+	);
+
+	macc2_uut uut (
+        .clk(clk),
+        .ce(ce),
+        .rst(rst),
+        .a(a),
+        .b(b),
+        .accum_out(accum_out),
+        .overflow(overflow)
+	);
+endmodule