Macro-Based Register Config Helper

Code

#include <stdio.h>
#include <stdint.h>
uint16_t reg;
// Define macros here
#define enable(X) ((X == 1)? (reg | (1<<0)) : reg = reg)
#define SET_MODE(X) (reg |= ((X)==1 ? (0b01<<1) : (X)==2 ? (0b10<<1) : (X)==3 ? (0b11<<1) : 0))
#define SPEED(X) (reg |= ((X)==1 ? (0b001<<3) : (X)==2 ? (0b010<<3) : (X)==3 ? (0b011<<3): (X)==4 ? (0b100<<3) : (X)==5 ? (0b101<<3): (X)==6 ? (0b110<<3) : (X)==7 ? (0b111<<3) : 0))

uint16_t build_register(uint8_t enable, uint8_t mode, uint8_t speed) {
    // Use macros to set fields
    reg= enable(enable);
    reg = SET_MODE(mode);
    reg = 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