Macro-Based Register Config Helper

Code

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

#define write(reg,len,pos,val) ((reg & (( 1<<len)-1 )) | val<< pos)

uint16_t build_register(uint8_t enable, uint8_t mode, uint8_t speed) {
    uint16_t ret = 0;
    ret= write(ret,1,0,enable);
    ret= write(ret,2,1,mode);
    ret= write(ret,3,3,speed);

    return ret;
}

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