Pack Multiple Fields into a 16-bit Control Register

Code

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

typedef struct{
    uint16_t MODE  : 3;
    uint16_t SPEED : 5;
    uint16_t RSVD0 : 2;
    uint16_t STATUS: 6;
}ControlReg_t;

typedef union{
    ControlReg_t bits;
    uint16_t result;
}ControlReg_u;

uint16_t pack_register(uint8_t mode, uint8_t speed, uint8_t status) {
    // Your logic here
    ControlReg_u reg;

    reg.bits.MODE = mode & 0x07;
    reg.bits.SPEED = speed & 0x1F;
    reg.bits.RSVD0 = 0;
    reg.bits.STATUS = status & 0x3F;

    return reg.result;
}

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;
}

Solving Approach