19. Extract a Bit Field from a 32-bit Register

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

uint32_t extract_field(uint32_t reg, uint8_t pos, uint8_t len) {
    // Your code here
    // Sa
    uint8_t i;
    uint32_t mask;
    uint32_t ret;

    for (i=0; i < len; i++) {
        mask = mask | (1 << pos+i) ;
    }
    // printf("mask = 0x%x ", mask);
    ret = (reg & mask) >> pos;
    
    return ret;
}

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;
}