diff --git a/testcode/lib/div-test.c b/testcode/lib/div-test.c
new file mode 100644
index 000000000..15018e653
--- /dev/null
+++ b/testcode/lib/div-test.c
@@ -0,0 +1,40 @@
+/* div-test.c
+**
+** This program tests the division and modulo operators
+** and the div() library function.
+**
+** 2002-10-24, Greg King
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+
+static bool test(int dividend, int divisor) {
+	div_t result;
+
+	(long)result = (long)div(dividend, divisor);
+	printf("%+d/%+d= %+d, %+d%%%+d= %+d, div()= %+d, %+d\n",
+		dividend, divisor, dividend / divisor,
+		dividend, divisor, dividend % divisor,
+		result.quot, result.rem);
+	return result.quot * divisor + result.rem != dividend;
+	}
+
+int main(void) {
+	bool t;
+
+	printf("\nTest of division and modulus operations:\n\n");
+	t =	test(+40, +3) ||
+		test(+40, -3) ||
+		test(-40, +3) ||
+		test(-40, -3);
+	if (t)
+		printf("\nThe div() function made a wrong result!\n");
+#ifdef __ATARI__
+	/* Atari DOS 2 clears the screen after program-termination, so wait. */
+	printf("\nTap a key, to exit. ");
+	getchar();
+#endif
+	return (int)t;
+	}