Macro-Based Register Config Helper

Code

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

// Bit-field macros
#define SET_ENABLE(reg, en)    (reg |= ((en & 0x1) << 0))
#define SET_MODE(reg, mode)    (reg |= ((mode & 0x3) << 1))
#define SET_SPEED(reg, speed)  (reg |= ((speed & 0x7) << 3))

int main() {
    uint16_t reg = 0;
    uint8_t enable, mode, speed;

    // Read values
    scanf("%hhu %hhu %hhu", &enable, &mode, &speed);

    // Use macros to pack fields
    SET_ENABLE(reg, enable);
    SET_MODE(reg, mode);
    SET_SPEED(reg, speed);

    // Bits 6–7 remain 0 automatically

    printf("%hu", reg);

    return 0;
}

Solving Approach