Pack Multiple Fields into a 16-bit Control Register

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

#define MODE_SIZE 0x7
#define SPEED_SIZE 0x1F
#define RESERVED_SIZE 0X3
#define STATUS_SIZE 0X3F

#define MODE_POSITION 0
#define SPEED_POSITION 3
#define RESERVED_POSITION 8
#define STATUS_POSITION 10

uint16_t pack_register(uint8_t mode, uint8_t speed, uint8_t status) {
    // Your logic here
    mode&=MODE_SIZE;
    speed&=SPEED_SIZE;
    status&=STATUS_SIZE;

    uint16_t mask=0U;
    mask|=status;
    mask<<=STATUS_POSITION;
    mask|=(speed<<=SPEED_POSITION);
    mask|=mode;
    return mask;
}

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;
}