Multiply and sum implementations using only bitwise operators. (negative numbers are not supported.)

sum-and-multiply.c

int get_bit(int val, int bit) {
    return (val >> bit) & 1;
}

/* sets ith bit to zero*/
int set_zero_bit(int val, int i) {
	return val & (~(1 << i));
}

/* sets ith bit to one*/
int set_one_bit(int val, int i) {
	return val | (1 << i);
}

/* adds 2^i to a */
int power_of_two_sum(int a, int i) {
	int bit;
	int total_bits = sizeof(int) * 8;
	while (i < total_bits && (bit = get_bit(a, i))) {
		a = set_zero_bit(a, i);
		i++;
	}
	if (i >= total_bits)
		return -1;
	return set_one_bit(a, i);
}

int implemented_sum(int a, int b) {
	int i = 0;
	int total_bits = sizeof(int) * 8;
	int result = a;
	while (i < total_bits) {
		int bit = get_bit(b, i);
		if (bit == 1)
			result = power_of_two_sum(result, i);
		i++;
	}
	return result;
}
int implemented_multiply(int a, int b) {
	int bits = sizeof(int) * 8;
	int result = 0;
	for (int i = 0; i < bits; i++) {
		if (get_bit(b, i) == 1) {
			result = implemented_sum(result, a << i);
 		}
	}
	return result;
}