test_negative
test_negative(4, a, 1, 0, 0, 0);
test_negative(4, a, 64, 0, 0, 0);
test_negative(4, a, 128, 0, 0, 0);
test_negative(4, a, 192, 0, 0, 0);
test_negative(4, a, 255, 0, 0, 0);
test_negative(4, a, 192, 0, 0, 1);
test_negative(4, a, 1, 0, 0, 0);
test_negative(6, a, 0x24446801, 0x40e40800, 0xdeaebeef, 0xdefbeef);
test_negative(6, a, 0x24446800, 0xf0e40800, 0xeeaebeef, 0x10101010);
test_negative(4, a, 192, 168, 0, 1);
test_negative();
test_negative();
test_negative();