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

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

#define SET(reg,bit,val) (reg |= (val << bit));

uint16_t pack_register(uint8_t mode, uint8_t speed, uint8_t status) {
    uint32_t reg;
    SET(reg,0,mode);
    SET(reg,3,speed);
    SET(reg,10,status);
    //SET(reg,0,mode);
    return reg;
}

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;
}