Carry Flag in 8-bit Addition

Code

#include <stdio.h>
#include <stdint.h>

void add_with_carry(uint8_t a, uint8_t b, uint8_t* result, uint8_t* carry) {
    *result = a + b;

    // Count how many bits not set
    uint8_t a_to_overflow;
    // Solution 1
    // uint8_t shift = a;
    // for(int i = 0; i < 8; i++) {
    //     if(!(shift & 1U)) {
    //         a_to_overflow |= 1 << i;
    //     }
    //     shift >>= 1;
    // }
    // Solution 2
    a_to_overflow = a ^ 0xFF;

    if (b > a_to_overflow) {
        *carry = 1;
    }

}

int main() {
    uint8_t a, b, result, carry;
    scanf("%hhu %hhu", &a, &b);

    add_with_carry(a, b, &result, &carry);

    printf("%u ", result);
    printf("%u", carry);
    return 0;
}

Solving Approach