Macro-Based Register Config Helper

Code

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

// Macros to set fields in a register
#define SET_BIT(reg, pos) ((reg) |= (1U << (pos)))
#define CLEAR_BITS(reg, pos, len) ((reg) &= ~(((1U << (len)) - 1) << (pos)))
#define SET_FIELD(reg,pos,len,value) do{\
CLEAR_BITS(reg,pos,len);\
((reg)|=((value & (1U<<len)-1)<< pos));} while(0)
uint16_t build_register(uint8_t enable, uint8_t mode, uint8_t speed){
    uint16_t reg =0;
    if (enable) SET_BIT(reg,0);

    SET_FIELD(reg,1,2,mode);
    SET_FIELD(reg,3,3,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