76. Construct UART Data Frame with Parity Bit

#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 count = 0;

    for(int i = 0; i < 8; i++){
        if(data & (1 << i)){
            count++;
        }
    }

    if(ctrl->parity_enable == 0){
        return data;
    }

    // EVEN
    if(ctrl->parity_type == 0){
        if(count % 2 != 0){ // lẻ → thêm 1
            data |= (1 << 7);
        }
    }
    // ODD
    else{
        if(count % 2 == 0){ // chẵn → thêm 1
            data |= (1 << 7);
        }
    }

    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;
}