[kazinator]

Wrong. -1 >> 1 produces an implementation-defined value in C.

-1/2 used to also be implementation-defined; C99 started to require truncation toward zero.

That actually makes division unsuitable for simulating bit shifting; you generally want a right shift of a negative quantity to have predictable behavior: either extend the sign, or bring in a zero. Truncating division toward zero doesn't do either; it propagates the sign, until zero is hit.

If you can, avoid signed types if you're working with bit fields.