Implement TestBench for ArithmeticUnit

ArithmeticUnit_TestBench.sv

@@ -0,0 +1,67 @@
+`default_nettype none
+
+module ArithmeticUnit_TestBench;
+
+var logic[2:0] opcode;
+var logic[7:0] operandA;
+var logic[7:0] operandB;
+tri[7:0] result;
+
+ArithmeticUnit lu(
+  .opcode(opcode),
+  .operandA(operandA),
+  .operandB(operandB),
+  .result(result)
+);
+
+// synthesis translate_off
+initial begin
+    $timeformat(-9, 2, " ns", 20);
+    
+    $display("%0t Initial Reset", $time);
+    opcode = 3'b000;
+    operandA = 8'b00000000;
+    operandB = 8'b00000000;
+    #20 assert(result == 8'b00000000);
+
+    // First set of operands
+    operandA = 8'b00000000;
+    operandB = 8'b01010101;
+
+    $display("%0t ADD 1", $time);
+    opcode = 3'b100;
+    #20 assert(result == 8'b01010101);
+
+    $display("%0t SUB 1", $time);
+    opcode = 3'b101;
+    #20 assert(result == 8'b10101011);
+
+    // Second set of operands
+    operandA = 8'b11111111;
+    operandB = 8'b01010101;
+
+    $display("%0t ADD 2", $time);
+    opcode = 3'b100;
+    #20 assert(result == 8'b01010100); // With carry, we don't have flags yet
+
+    $display("%0t SUB 2", $time);
+    opcode = 3'b101;
+    #20 assert(result == 8'b10101010);
+
+    // Third set of operands
+    operandA = 8'b00001111;
+    operandB = 8'b01010101;
+
+    $display("%0t ADD 3", $time);
+    opcode = 3'b100;
+    #20 assert(result == 8'b01100100);
+
+    $display("%0t SUB 3", $time);
+    opcode = 3'b101;
+    #20 assert(result == 8'b10111010);
+
+    $display("Success!");
+end
+// synthesis translate_on
+
+endmodule