Macro-Based Register Config Helper

Code

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

// Define macros here
#define ENABLE_POS      0
#define MODE_POS        1
#define SPEED_POS       3
#define ENABLE_MASK     1U << ENABLE_POS
#define MODE_MASK       3U << MODE_POS
#define SPEED_MASK      7U << SPEED_POS
#define SET_ENABLE(r,v) ((r) = ((r & ~(ENABLE_MASK)) | (v << ENABLE_POS)))
#define SET_MODE(r,v)   ((r) = ((r & ~(MODE_MASK))   | (v << MODE_POS)))
#define SET_SPEED(r,v)  ((r) = ((r & ~(SPEED_MASK))  | (v << SPEED_POS)))

uint16_t build_register(uint8_t enable, uint8_t mode, uint8_t speed) {
    // Use macros to set fields
    uint16_t r = 0;
    SET_ENABLE(r,enable);
    SET_MODE(r,mode);
    SET_SPEED(r,speed);
    return r;
}

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