#include <stdio.h>
#include <stdint.h>
// Define macros here
#define ENABLE_POS 0
#define MODE_POS   1
#define SPEED_POS  3
#define ENABLE_MASK 0x01
#define MODE_MASK   0x03
#define SPEED_MASK  0x07
#define SET_ENABLE(x) (((x) & ENABLE_MASK) << ENABLE_POS)
#define SET_MODE(x)   (((x) & MODE_MASK)   << MODE_POS)
#define SET_SPEED(x)  (((x) & SPEED_MASK)  << SPEED_POS)
uint16_t build_register(uint8_t enable, uint8_t mode, uint8_t speed) {
    // Use macros to set fields
    return SET_ENABLE(enable) | SET_MODE(mode) | SET_SPEED(speed);
}
int main() {
    uint8_t enable, mode, speed;
    scanf("%hhu %hhu %hhu", &enable, &mode, &speed);
    uint16_t reg = build_register(enable, mode, speed);
    printf("%u", reg);
    return 0;
}
Input
1 2 4
Expected Output
37