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) {
    // Your code here
    uint8_t mask;
    switch (len) {
        case 1 :
            mask = 0b00000001;
            break;
        
        case 2 :
            mask = 0b00000011;
            break;
        
        case 3 :
            mask = 0b00000111;
            break;
        
        case 4 :
            mask = 0b00001111;
            break;
        
        case 5 :
            mask = 0b00011111;
            break;
        
        case 6 :
            mask = 0b00111111;
            break;
        
        case 7 :
            mask = 0b01111111;
            break;
        
        case 8 :
            mask = 0b11111111;
            break;
        
    }

    reg >>= pos;
    reg &= mask;

    return reg;
}

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