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

/* Field masks */
#define ENABLE_MASK  0x1
#define MODE_MASK    0x3
#define SPEED_MASK   0x7

/* Field macros */
#define SET_ENABLE(x)  (((x) & ENABLE_MASK) << ENABLE_POS)
#define SET_MODE(x)    (((x) & MODE_MASK)   << MODE_POS)
#define SET_SPEED(x)   (((x) & SPEED_MASK)  << SPEED_POS)

uint16_t build_register(uint8_t enable, uint8_t mode, uint8_t speed) {
    // Use macros to set fields
    uint16_t reg=0U;
    reg|=SET_ENABLE(enable);
    reg|=SET_MODE(mode);
    reg|=SET_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