123. Carry Flag in 8-bit Addition

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

#define signbit 0x80

void add_with_carry(uint8_t a, uint8_t b, uint8_t* result, uint8_t* carry) {
    // Your logic here
    uint8_t i, reg=0, c=0, bita=0, bitb=0 ;

    for (i=0; i < 8; i++) {
        bita = a & 1;
        bitb = b & 1;
        reg = reg >> 1;

        if ((bita == 1) && (bitb == 1)) {
            if (c == 0) {
               c = 1;
                reg = (reg | 0);
            }
            else {
                c = 1;
                reg = (reg | 0x80);
            }
        }

        if ((bita == 1) && (bitb == 0)) {
            if (c == 0) {
                c = 0;
                reg = (reg | 0x80);
            }
            else {
               c = 1;
               reg = (reg | 0);
            }
        }
 
        if ((bita == 0) && (bitb == 0)) {
            if (c == 0) {
                c = 0;
                reg = (reg | 0);
            }
            else {
               c = 0;
               reg = (reg | 0x80);
            }
        }

        if ((bita == 0) && (bitb == 1)) {
            if (c == 0) {
                c = 0;
                reg = (reg | 0x80);
            }
            else {
               c = 1;
               reg = (reg | 0);
            }
        }

        a = a >> 1;
        b = b >> 1;
    }    

    *result = reg;
    *carry = c;

}

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;
}

add the regisers bit by bit with carry.

isolate the bits by shifting right and masking higer bits. 

put results in register from the end and shift it right