add bh_asserts.sv. Untested

src/bh_assert.sv

@@ -0,0 +1,48 @@
+
+int bh_assert_pass_count = 0;
+int bh_assert_fail_count = 0;
+
+logic bh_info_enable = 0;
+
+function logic bh_assert_equal(int val, int expected, string description);
+    // display results
+    $timeformat(-9, 2, " ns", 20);
+    $display(
+        "%t: %s: %d %s %d - %s",
+        $time,
+        val == expected ? "PASS" : "FAIL",
+        val,
+        val == expected ? "==" : "!=",
+        expected,
+        description
+    );
+
+    // update statistics
+    if (val == expected) begin
+        bh_assert_pass_count = bh_assert_pass_count + 1;
+    end else begin
+        bh_assert_fail_count = bh_assert_fail_count + 1;
+    end
+
+    return val == expected; 
+endfunction
+
+function void bh_assert_stats();
+    $timeformat(-9, 2, " ns", 20);
+    $display("%t: DONE: ");
+    if (bh_assert_pass_count + bh_assert_fail_count == 0) begin
+        $display("ERROR: no assertions found");
+        // TODO: error in a better way?
+    end else if (bh_assert_fail_count > 0) begin
+        $display("ERROR: some tests failed");
+    end else begin
+        $display("SUCCESS: all tests passed");
+    end
+endfunction
+
+function void bh_info(string description);
+    if (bh_info_enable) begin
+        $display(description);
+    end
+endfunction
+