Validate Configuration Register Layout

Code

#include <stdio.h>

typedef struct {
    unsigned short reg;
} ConfigRegister;

int validate_config(ConfigRegister *cfg) {

    // Check if Enable bit is set (bit 0)
    if ((cfg->reg & 0x0001) == 0)
        return 0;

    // Extract priority (bits 2–3)
    if ((cfg->reg & 0xFC) == 0x03)  // Invalid priority
        return 0;

    // Check reserved bits (bits 4–15) are all 0
    if ((cfg->reg & 0xFFF0) != 0)
        return 0;

    return 1;
    
}

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

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

    return 0;
}

Solving Approach