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
    if(pos > 31 || len > 32 || len + pos > 32){
        return (uint32_t)-1;
    }
    reg &= ~(((1 << len) - 1) << pos);
    val &= ((1 << len) - 1);
    return reg | (val << pos);
}

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