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

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

#define READ_MODE(m) (m & 0xFCFF)
#define READ_SPEED(s) ((s << 3)& 0xFCFF)
#define READ_STATUS(s) ((s << 10)& 0xFCFF)

uint16_t pack_register(uint8_t mode, uint8_t speed, uint8_t status) {
    // Your logic here
    uint16_t r = 0;
    r|= READ_MODE(mode);
    r|= READ_SPEED(speed);
    r|= READ_STATUS(status);
    return r;
}

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;
}