Pack Multiple Fields into a 16-bit Control Register

Code

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

uint16_t reg;

#define set_mode_bit(val) do{\
                            reg &= ~(0x7U << 0);\
                            reg |= ((val & 0x7U) << 0);\
                            } while(0)
                            
#define set_speed_bit(val) do{\
                            reg &= ~(0x1F << 3);\
                            reg |= ((val & 0x1F) << 3);\
                            } while(0)
                            
#define set_reserved_bit() do{\
                            reg &= ~(0x3U << 8);\
                            } while(0)

#define set_status_bit(val) do{\
                            reg &= ~(0x3F << 10);\
                            reg |= ((val & 0x3F) << 10);\
                            } while(0)

uint16_t pack_register(uint8_t mode, uint8_t speed, uint8_t status) {
    // Your logic here
    set_mode_bit(mode);
    set_speed_bit(speed);
    set_reserved_bit();
    set_status_bit(status);
    return reg;
}

int main() {
    uint8_t mode, speed, status;
    scanf("%hhu %hhu %hhu", &mode, &speed, &status);

    uint16_t reg = pack_register(mode, speed, status);
    printf("%u", reg);
    return 0;
}

Solving Approach