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) {
    uint8_t frame = data & 0x7f;
    if(ctrl->parity_enable){
        int i;
        int num_ones = 0;
        for(i = 0; i < 7; i++){
            if(data & (0x1 << i)){
                num_ones++;
            }
        }
        if(ctrl->parity_type){
            // odd parity
            frame |= !(num_ones % 2) << 7;
        }else{
            // even
            frame |= (num_ones % 2) << 7;
        }
    }
    return frame;
}

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