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

// Masks
#define ENABLE_MASK     (1U << ENABLE_POS)
#define MODE_MASK       (0x3U << MODE_POS)    // 2 bits
#define SPEED_MASK      (0x7U << SPEED_POS)   // 3 bits

// ----------------------------
// Field Setter Macros
// ----------------------------
#define SET_ENABLE(val)   (((val) & 0x1U) << ENABLE_POS)
#define SET_MODE(val)     (((val) & 0x3U) << MODE_POS)
#define SET_SPEED(val)    (((val) & 0x7U) << SPEED_POS)

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;  // Reserved bits remain 0
    return 0;
}

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