probe process.function("foo").return {
    printf("x1 = %#x\n", register("x1"));
    printf("u x1 = %#x\n\n", u_register("x1"));

    printf("w1 = %#x\n", register("w1"));
    printf("u w1 = %#x\n", u_register("w1"));
    exit()
}
