77. Validate Configuration Register Layout

#include <stdio.h>

typedef struct {
    unsigned short reg;
} ConfigRegister;

int validate_config(ConfigRegister *cfg) {
    unsigned short value = cfg->reg;

    if ((value & 0x0001) == 0)
    {
           return 0;
    }

    unsigned short priority = (value >> 2) & 0x03;
    if (priority == 0x03) 
    {
        return 0;
    }

    if ((value & 0xFFF0) != 0)
    {
        return 0;
    }

    return 1; 
}

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

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

    return 0;
}