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) {
    
    int mask;

    mask = 0x0;
    if(!ctrl -> parity_enable)
        return data;
    else {
        int i = 0;
        int tmp = data;
        while(tmp)
        {
            tmp = tmp & tmp - 1;
            i++;
        }
        if(!(i % 2) && ctrl -> parity_type)
            mask = 0x80;
        else if(i % 2 && !ctrl -> parity_type)
            mask = 0x80;
        }
        data |= mask;

    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