Macro-Based Register Config Helper

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

#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_FIELD(val, mask, pos) (((val) & (mask)) << (pos))

uint16_t build_register(uint8_t enable, uint8_t mode, uint8_t speed) {
    uint16_t res = 0;
    res |= SET_FIELD(enable, ENABLE_MASK, ENABLE_POS);
    res |= SET_FIELD(mode, MODE_MASK, MODE_POS);
    res |= SET_FIELD(speed, SPEED_MASK, SPEED_POS);

    return res;
}

int main() {
    uint8_t enable, mode, speed;
    
    if (scanf("%hhu %hhu %hhu", &enable, &mode, &speed) == 3) {
        uint16_t reg = build_register(enable, mode, speed);
        printf("%u\n", reg);
    }

    return 0;
}