Control Register Using Nested Bitfields

Code

#include <stdio.h>

typedef union {
    unsigned char reg;
    struct {
        unsigned char enable : 1;
        unsigned char mode : 1;
        unsigned char priority : 2;
        unsigned char reserved : 4;
    } bits;
} ControlRegister;

// Write your logic here
int validate_register(ControlRegister *ctrl) {
    unsigned char mask_enable = 1U << 0;
    unsigned char mask_mode = 1U << 1;
    unsigned char mask_priority = 0x03 << 2;
    unsigned char mask_reserved = 0x0F << 4;
    unsigned char Reg = ctrl->reg; 
    // checking for enable bit
    if ((mask_enable & Reg) == 0){return 0;}
    // checking for mode bit
    // if ((mask_mode & Reg) >> 1 == 0){return 0;}
    // checking for priority bit
    if ((mask_priority & Reg) >> 2 > 2){return 0;}
    // checking for reserved bit
    if (((mask_reserved & Reg) >> 4) != 0){return 0;}
    return 1;
}

int main() {
    ControlRegister ctrl;
    scanf("%hhx", &ctrl.reg);

    int result = validate_register(&ctrl);
    printf("%d", result);

    return 0;
}

Solving Approach