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;

uint8_t create_uart_frame(uint8_t data, UART_Control *ctrl) {
    // Your logic here
    uint8_t reg = 0x00;
    if ( ctrl->parity_enable == 0 ) {
        reg &= ~( 1 << 7 );
    } else {
        int count = 0; 
        uint8_t n = data;
        while(n) {
            count += (n & 1);
            n >>= 1;
        }
        if ( ctrl->parity_type == 0 )  {
            // even parity
            if (count % 2 == 0) {
                reg &= ~( 1 << 7 );
            } else {
                reg |= ( 1 << 7);
            }
        } else {
            // odd parity
            if (count % 2 == 0) {
                reg |= ( 1 << 7);
            } else {
                reg &= ~( 1 << 7 );
            }
        }
    }
    reg |= ( ( data & 0x7F ) );
    return reg;
}

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