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

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

uint16_t pack_register(uint8_t mode, uint8_t speed, uint8_t status) {
    uint16_t final = 0;
    final |= (mode & (1U << 3) - 1) << 0;
    final |= (speed & (1U << 5) - 1) << 3;
    final |= (status & (1U << 6) - 1) << 10;
    return final;
}

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;
}