Construct UART Data Frame with Parity Bit

Code

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

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

int count_bits(uint32_t num) 
{ 
    int count=0; 
    while(num) 
    { 
        if(num&1) 
        {
             count++; 
         }
              num>>=1;
     } 
        return count;   
 }


uint8_t create_uart_frame(uint8_t data, UART_Control *ctrl) {
    if (ctrl->parity_enable) {
        int bits = count_bits(data & 0x7F); // only 7-bit data
        uint8_t parity_bit = 0;

        if (ctrl->parity_type == 0) {  
            // Even parity
            parity_bit = (bits % 2 == 0) ? 0 : 1;
        } else {  
            // Odd parity
            parity_bit = (bits % 2 == 0) ? 1 : 0;
        }

        // put parity bit at MSB (bit7)
        data = (data & 0x7F) | (parity_bit << 7);
    }
    return data;
}


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