Validate Configuration Register Layout

Code

#include <stdio.h>

typedef struct {
    unsigned short reg;
} ConfigRegister;

int validate_config(ConfigRegister *cfg) {
    // Write logic using pointer access
    unsigned short reg = cfg->reg;

    // Bit 0 must be 1
    if (!(reg & 0x1))
        return 0;

    // Bits 2–3 must NOT be 11
    if (((reg >> 2) & 0x3) == 3)
        return 0;

    // Bits 4–15 must be 0
    if (reg & 0xFFF0)
        return 0;

    return 1;
}

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

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

    return 0;
}

Solving Approach