// always do unsigned division and adjust the signs later: in C integer
// division, the sign of the remainder is the same as the sign of the
// dividend, while the sign of the quotient is the product of the signs of
// always do unsigned division and adjust the signs later: in C integer
// division, the sign of the remainder is the same as the sign of the
// dividend, while the sign of the quotient is the product of the signs of