Made it clear that we are using SystemVerilog by renaming HDL files to end in .sv rather than .v

tests/asu_tb.sv

@@ -0,0 +1,124 @@
+`include "asu.v"
+
+module asu_tb #(width=8)();
+    logic [0:0] op;
+    logic [width-1:0] A;
+    logic [width-1:0] B;
+    logic [width-1:0] C;
+    logic [0:0] Cout;
+    logic [0:0] Cin;
+    logic [width-1:0] C_exp;
+    logic [0:0] Cout_exp;
+    logic [0:0] Cin_exp;   // TODO
+    
+    logic [0:0] Signed_overflow;
+
+    asu #(width) dut(op, A, B, C, Cout, Cin);
+
+    integer error_count;
+    initial begin
+        error_count = 0;
+        $display("Beginning ASU tests");
+
+        // Test basic addition of 0+1 = 1
+        op = 1'b0;
+        A = {width{1'b0}};
+        B = { {(width-1){1'b0}}, 1'b1};
+        C_exp = { {(width-1){1'b0}}, 1'b1};
+        Cout_exp = 1'b0;
+        Cin_exp = 1'b0;
+        #1;
+        if (C != C_exp || Cout != Cout_exp || Cin != Cin_exp || (Cin ^ Cout) != (Cin_exp ^ Cout_exp)) begin
+            $display("\t\x1b[38;5;9mOp 0b%b(0b%b, 0b%b) produced 0b%b%b_%b but 0b%b%b_%b was expected\x1b[m", op, A, B, Cin, Cout, C, Cin_exp, Cout_exp, C_exp);
+            error_count = error_count + 1;
+        end
+
+        // Test underflow from 0-1 = UINTMAX
+        op = 1'b1;
+        C_exp = {(width){1'b1}};
+        Cout_exp = 1'b0;
+        Cin_exp = 1'b0;
+        #1;
+        if (C != C_exp || Cout != Cout_exp || Cin != Cin_exp || (Cin ^ Cout) != (Cin_exp ^ Cout_exp)) begin
+            $display("\t\x1b[38;5;9mOp 0b%b(0b%b, 0b%b) produced 0b%b%b_%b but 0b%b%b_%b was expected\x1b[m", op, A, B, Cin, Cout, C, Cin_exp, Cout_exp, C_exp);
+            error_count = error_count + 1;
+        end
+
+        // Test carry addition of 1+1 = 2
+        op = 1'b0;
+        A = { {(width-1){1'b0}}, 1'b1};
+        B = { {(width-1){1'b0}}, 1'b1};
+        C_exp = { {(width-2){1'b0}}, 2'b10};
+        Cout_exp = 1'b0;
+        Cin_exp = 1'b0;
+        #1;
+        if (C != C_exp || Cout != Cout_exp || Cin != Cin_exp || (Cin ^ Cout) != (Cin_exp ^ Cout_exp)) begin
+            $display("\t\x1b[38;5;9mOp 0b%b(0b%b, 0b%b) produced 0b%b%b_%b but 0b%b%b_%b was expected\x1b[m", op, A, B, Cin, Cout, C, Cin_exp, Cout_exp, C_exp);
+            error_count = error_count + 1;
+        end
+
+        // Test overflow from  UINTMAX+1 = 0
+        A = {(width){1'b1}};            // UINTMAX
+        B = { {(width-1){1'b0}}, 1'b1}; // 1
+        C_exp = {(width){1'b0}};
+        Cout_exp = 1'b1;
+        Cin_exp = 1'b1;
+        #1;
+        if (C != C_exp || Cout != Cout_exp || Cin != Cin_exp || (Cin ^ Cout) != (Cin_exp ^ Cout_exp)) begin
+            $display("\t\x1b[38;5;9mOp 0b%b(0b%b, 0b%b) produced 0b%b%b_%b but 0b%b%b_%b was expected\x1b[m", op, A, B, Cin, Cout, C, Cin_exp, Cout_exp, C_exp);
+            error_count = error_count + 1;
+        end
+
+        // Tests INTMAX+1
+        op = 1'b0;
+        A = {1'b0, {(width-1){1'b1}}};          // INTMAX
+        B = {{(width-1){1'b0}}, 1'b1};          // 1
+        C_exp    = {1'b1, {(width-1){1'b0}}};   // -INTMAX
+        Cin_exp  = 1'b1;
+        Cout_exp = 1'b0;
+        #1;
+        if (C != C_exp || Cout != Cout_exp || Cin != Cin_exp || (Cin ^ Cout) != (Cin_exp ^ Cout_exp)) begin
+            $display("\t\x1b[38;5;9mOp 0b%b(0b%b, 0b%b) produced 0b%b%b_%b but 0b%b%b_%b was expected\x1b[m", op, A, B, Cin, Cout, C, Cin_exp, Cout_exp, C_exp);
+            error_count = error_count + 1;
+        end
+
+        op = 1'b0;
+        A = {1'b1, {(width-1){1'b0}}};  // -INTMAX
+        B = {1'b1, {(width-1){1'b0}}};  // -INTMAX
+        C_exp    = {width{1'b0}};       // 0
+        Cin_exp  = 1'b0;
+        Cout_exp = 1'b1;
+        #1;
+        if (C != C_exp || Cout != Cout_exp || Cin != Cin_exp || (Cin ^ Cout) != (Cin_exp ^ Cout_exp)) begin
+            $display("\t\x1b[38;5;9mOp 0b%b(0b%b, 0b%b) produced 0b%b%b_%b but 0b%b%b_%b was expected\x1b[m", op, A, B, Cin, Cout, C, Cin_exp, Cout_exp, C_exp);
+            error_count = error_count + 1;
+        end
+
+        op = 1'b1;
+        A = {1'b0, {(width-1){1'b1}}}; // INTMAX
+        B = {1'b1, {(width-1){1'b0}}}; // -INTMAX
+        C_exp    = {width{1'b1}};      // -1
+        Cin_exp  = 1'b1;
+        Cout_exp = 1'b0;
+        #1;
+        if (C != C_exp || Cout != Cout_exp || Cin != Cin_exp || (Cin ^ Cout) != (Cin_exp ^ Cout_exp)) begin
+            $display("\t\x1b[38;5;9mOp 0b%b(0b%b, 0b%b) produced 0b%b%b_%b but 0b%b%b_%b was expected\x1b[m", op, A, B, Cin, Cout, C, Cin_exp, Cout_exp, C_exp);
+            error_count = error_count + 1;
+        end
+
+        op = 1'b1;
+        A = {1'b1, {(width-1){1'b0}}};          // -INTMAX
+        B = {{(width-1){1'b0}}, 1'b1};          // 1
+        C_exp    = {1'b0, {(width-1){1'b1}}};   // INTMAX
+        Cin_exp  = 1'b0;
+        Cout_exp = 1'b1;
+        #1;
+        if (C != C_exp || Cout != Cout_exp || Cin != Cin_exp || (Cin ^ Cout) != (Cin_exp ^ Cout_exp)) begin
+            $display("\t\x1b[38;5;9mOp 0b%b(0b%b, 0b%b) produced 0b%b%b_%b but 0b%b%b_%b was expected\x1b[m", op, A, B, Cin, Cout, C, Cin_exp, Cout_exp, C_exp);
+            error_count = error_count + 1;
+        end
+
+        if (error_count == 0) $display("\x1b[38;5;10mAll ASU tests passing\x1b[m");
+        else $display("\x1b[38;5;9m%0d ASU test(s) failing\x1b[m", error_count);
+    end
+endmodule