Macro-Based Register Config Helper

Code

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

// Define macros here
#define set_enable(reg)   ((uint16_t)((reg & ((1<<1) - 1)) << 0))
#define set_mode(reg)     ((uint16_t)((reg & ((1<<2) - 1)) << 1))
#define set_speed(reg)    ((uint16_t)((reg & ((1<<3) - 1)) << 3))

uint16_t build_register(uint8_t enable, uint8_t mode, uint8_t speed) {
    // Use macros to set fields
    uint16_t reg = 0;
    reg |= set_enable(enable);
    reg |= set_mode(mode);
    reg |= set_speed(speed);
    return reg;
}

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