77. Validate Configuration Register Layout

#include <stdio.h>

#define MASK(width, pos) (((1u<<width)-1)<<pos)

typedef struct {
    unsigned short reg;
} ConfigRegister;

int validate_config(ConfigRegister *cfg) {
    if ((cfg->reg & MASK(1,0)) == 0){
        return 0;
    }

    if ((cfg->reg & MASK(2,2)) == 3){
        return 0;
    }

    if ((cfg->reg & MASK(12,4)) != 0){
        return 0;
    }

    return 1;
}

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

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

    return 0;
}