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 sum_7bits(uint8_t data) {
    uint8_t sum;
    for (uint8_t i=0; i<7; i++) {
        sum += data & 1U;
        data = data >> 1;
    }
    return sum;
}

uint8_t create_uart_frame(uint8_t data, UART_Control *ctrl) {
    if (ctrl->parity_enable == 0) {
        return data;
    } else {
        int count = sum_7bits(data);
        if (ctrl->parity_type == 1) { // odd parity
            data = (count%2==0) ? data | 0x80 : data; // 1 even : 0 odd
        } else { // even parity
            data = (count%2==0) ? data: data | 0x80; // 0 even : 1 odd
        }
    }
    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