Macro-Based Register Config Helper

Code

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

// Field-setting macros
#define SET_ENABLE(x) ((x & 0x01) << 0) // Bit 0
#define SET_MODE(x) ((x & 0x03) << 1)   // Bits 1–2
#define SET_SPEED(x) ((x & 0x07) << 3)  // Bits 3–5
// Reserved bits 6–7 left 0

/**
 * Function to build a 16-bit register from individual fields
 *
 * @param enable: 1-bit field to enable or disable (bit 0)
 * @param mode: 2-bit field for mode selection (bits 1-2)
 * @param speed: 3-bit field for speed setting (bits 3-5)
 * @return: the constructed 16-bit register value
 *
 * eg: enable=1, mode=3 (11), speed=5 (101)
 * result: 0b0000000001011101 = 0x5D = 93
 */
uint16_t build_register(uint8_t enable, uint8_t mode, uint8_t speed)
{
    uint16_t reg = 0;

    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