Extract a Bit Field from a 32-bit Register

Code

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

uint32_t extract_field(uint32_t reg, uint8_t pos, uint8_t len) {

    uint32_t result1 = 0x00;
    uint32_t result = 0x00;
    uint8_t mask= 0x00;
    //printf("%d \n",pos);
    //printf("%d \n",len);
    if (len <= 5)
    {
        mask = 0x0f;
    }
    else
    {
        mask = 0xff;
    }
    for(int j = 0; j <= len; j++)
    {
        result = (reg >> pos) & mask;
        result1 |= result;
        //printf("pos:%d %d",j, result1);
    }
    return result1 ;
}

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

Solving Approach