Construct UART Data Frame with Parity Bit

Count 1s and assign msb

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

typedef struct {
    uint8_t parity_enable : 1;
    uint8_t parity_type   : 1;
    uint8_t reserved      : 6;
} UART_Control;

uint8_t create_uart_frame(uint8_t data, UART_Control *ctrl) {
    // Your logic here
    uint8_t ret_val = 0x7f & data;  //msb 0 remaining are data
    
    if(ctrl -> parity_enable){
        uint8_t cnt = 0, i = 0;
        while(i < 7){
            cnt += (0x01 & (data >> i));
            i++;
        }
        if(ctrl -> parity_type){
            ret_val |= (cnt%2 == 0) << 7; 
        }
        else{
            ret_val |= (cnt%2) << 7;
        }
    }
    return ret_val;
}

int main() {
    uint8_t data;
    scanf("%hhu", &data);  // 7-bit input

    uint8_t parity_enable, parity_type;
    scanf("%hhu %hhu", &parity_enable, &parity_type);

    UART_Control ctrl;
    ctrl.parity_enable = parity_enable;
    ctrl.parity_type = parity_type;

    uint8_t frame = create_uart_frame(data, &ctrl);
    printf("frame = 0x%02X", frame);

    return 0;
}

Solving Approach

firstly count the number of ones in the data number after setting a mask and getting the data bits mask = 0x7f sets msb = 0. calculate and assign parity bit by | = parity << 7 .