Macro-Based Register Config Helper

Code

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

// Define macros here
#define SET_CONTROL_REG_EN(reg,en)          \
    (reg) |= ((en) << 0)

#define SET_CONTROL_REG_MODE(reg,mode)      \
    (reg) |= ((mode) << 1)

#define SET_CONTROL_REG_SPEED(reg,speed)    \
    (reg) |= ((speed) << 3)

#define SET_CONTROL_REG_RESERVED(reg)       \
    (reg) &= ~((1 << 6) & (1 << 7))

uint16_t build_register(uint8_t enable, uint8_t mode, uint8_t speed) {
    // Use macros to set fields
    uint16_t reg = 0; 
    SET_CONTROL_REG_EN(reg,enable);
    SET_CONTROL_REG_MODE(reg,mode);
    SET_CONTROL_REG_SPEED(reg,speed);
    SET_CONTROL_REG_RESERVED(reg);

    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