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

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


uint16_t pack_register(uint8_t mode, uint8_t speed, uint8_t status) {
    uint16_t result;
    uint8_t arr1[4] = { mode, speed, 0, status};
    uint8_t arr[4] =  { 0x7, 0x1F, 0x3, 0x3F };
    uint8_t shifts[4] = { 0,3,8,10};
    for(uint8_t i=0; i<4; i++)
    {
      result &= ~(arr[i] << shifts[i]);
      result |= (arr1[i] << shifts[i]); 
       
    }
    return 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;
}