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) {
    // Your code here

    int working_reg = reg >> (pos + len);
    working_reg = working_reg << len;
    working_reg += val;
    working_reg = working_reg << pos;

    reg = reg & ((1 << (pos)) - 1);
    working_reg += reg;

    return working_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;
}

Solving Approach