21. Replace Bit Field in a 32-bit Register

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

uint32_t replace_field(uint32_t reg, uint32_t val, uint8_t pos, uint8_t len) {
    // Your code here
    uint32_t mask=0;
    uint8_t i=0;
    for(i=0;i<len;i++)
    {
        mask |= (1<<i);//Generate mask for given length
    }
    mask = ~(mask <<pos);// Align the mask with position and invert it
    reg &= mask; //Clear the targeted bits in register
    reg |= (val<<pos);//Set the new value at targeted position
    return reg;
}

int main() {
    uint32_t reg, val;
    uint8_t pos, len;
    scanf("%u %u %hhu %hhu", &reg, &val, &pos, &len);
    printf("%u", replace_field(reg, val, pos, len));
    return 0;
}