Macro-Based Register Config Helper

Code

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

// Macros to set fields in 16-bit register
#define SET_ENABLE(reg, val) ((reg) |= ((val & 0x1) << 0))
#define SET_MODE(reg, val)   ((reg) |= ((val & 0x3) << 1))
#define SET_SPEED(reg, val)  ((reg) |= ((val & 0x7) << 3))

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

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

                SET_ENABLE(reg, enable);
                    SET_MODE(reg, mode);
                        SET_SPEED(reg, speed);
                            // RESERVED bits (6-7) remain 0

                                printf("%u\n", reg);  // Print final 16-bit register value in decimal

                                    return 0;
                                    }

Solving Approach