Macro-Based Register Config Helper

Code

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

// Define macros here
#define ENABLE(a_reg, bit) ((bit) ? (a_reg |= (1<<0)) : (a_reg &= ~(1<<0)))
#define MODE(a_reg, mode) (a_reg|=(((uint16_t)mode<<1))) 
#define SPEED(a_reg,speed) (a_reg|=(((uint16_t)speed<<3)))

uint16_t build_register(uint8_t enable, uint8_t mode, uint8_t speed) {
    // Use macros to set fields
    uint16_t l_bit = 0;

    ENABLE(l_bit, enable);
    MODE(l_bit,mode);
    SPEED(l_bit,speed);
    
    return l_bit;
}

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;
}

Solving Approach