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 count_1s_data(uint8_t data)
{
    uint8_t cnt = 0;
    for(int i = 0; i<7;i++)
    {
        if(data & (1<<i))
        {
            cnt++;
        }
    }
    return cnt;
}

uint8_t create_uart_frame(uint8_t data, UART_Control *ctrl) {
    data = data & 0x7F;
    uint8_t cnt = count_1s_data(data);
    if(ctrl->parity_enable == 0 )
    {
        return data;
    }
    if(ctrl->parity_type == 0)
    {
        if(cnt%2 != 0)
            return data | 0x80;
        else
            return data & 0x7F;
    }
    else
    {
        if(cnt%2 == 0)
            return data | 0x80;
        else
            return data & 0x7F;
    }
}

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