25. Pack Multiple Fields into a 16-bit Control Register

#include <stdio.h>
#include <stdint.h>

#define FIELD_MASK(len)     ((1u << (len)) - 1u)

uint16_t pack_register(uint8_t mode, uint8_t speed, uint8_t status) {
    // Your logic here
    uint16_t res = 0;
    res |= ((mode & FIELD_MASK(3)) << 0);
    res |= ((speed & FIELD_MASK(5)) << 3);
    res |= ((status & FIELD_MASK(6)) << 10);
    return res;
}

int main() {
    uint8_t mode, speed, status;
    scanf("%hhu %hhu %hhu", &mode, &speed, &status);

    uint16_t reg = pack_register(mode, speed, status);
    printf("%u", reg);
    return 0;
}