77. Validate Configuration Register Layout

#include <stdio.h>

typedef struct {
    unsigned short reg;
} ConfigRegister;

int validate_config(ConfigRegister *cfg) {
    unsigned short max_val = 0xFFFF;
    unsigned short enable = 1;
    unsigned short priority = (~(max_val << 2)) << 2;
    unsigned short reserved = max_val << 4;
    return (cfg->reg & enable) && (cfg->reg ^ priority) && !(cfg->reg & reserved);
}

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

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

    return 0;
}