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

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

#define MODE(modeVal) ((0b111 & modeVal))
#define SPEED(speedVal) ((0b11111 & speedVal) << 3)
#define STATUS(statusVal) ((0b111111 & statusVal) << 10)

uint16_t pack_register(uint8_t mode, uint8_t speed, uint8_t status) {
    uint16_t control_register = 0;
    
    control_register |= MODE(mode);
    control_register |= SPEED(speed);
    control_register |= STATUS(status);

    return control_register;
}

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;
}