77. Validate Configuration Register Layout

#include <stdio.h>

typedef struct {
    unsigned short reg;
} ConfigRegister;

int validate_config(ConfigRegister *cfg) 
{
    unsigned short bits_enable = cfg->reg & 1u;
    unsigned short bits_priority = (cfg->reg >> 2) & 3u;
    unsigned short bits_reserved = (cfg->reg >> 4) & 0X0FFF;
    if (bits_enable == 1u && bits_priority != 3u && bits_reserved == 0u) 
    {
        return 1;
    }
    return 0;
}

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

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

    return 0;
}