77. Validate Configuration Register Layout

#include <stdio.h>

typedef struct {
    unsigned short reg;
} ConfigRegister;

int validate_config(ConfigRegister *cfg) {
    // Write logic using pointer access
    if ((cfg->reg & 1) == 0){
        return 0;
    }

    if (((cfg->reg & 0x0C) >> 2) == 0x03){
        return 0;
    }

    int mask = 0xFFF0;
    if ((cfg->reg & mask) >> 4 != 0){
        return 0;
    }

    return 1;
}

int main() {
    ConfigRegister cfg;
    scanf("%hx", &cfg.reg);

    int result = validate_config(&cfg);
    printf("%d", result);

    return 0;
}