Replace Bit Field in a 32-bit Register

Code

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

uint32_t replace_field(uint32_t reg, uint32_t val, uint8_t pos, uint8_t len) {
    uint32_t mask = (((1U<<len)-1) <<pos);
   uint32_t clear_reg = reg & ~mask ; // clear value
   uint32_t field_val = (val & ((1U << len) - 1)) << pos;
   return clear_reg | field_val;
    

} 

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;
}

Solving Approach