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) {
    return  (0U |               // variable à 0
            ((mode & 0x7) << 0)  |        // masque bits 0-2
            ((speed & 0x1F) << 3)  |   // masque bits 3-7
            ((status & 0x3F) << 10)); // masque bits 10-15
}

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;
}