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) {
    if (len == 0 || pos > 31 || (pos + len) > 32) return 0; // bảo vệ input
    uint32_t mask = (1U << len) - 1U;   // tạo mask len bit
    return (reg >> pos) & mask;         // trích ra trường bit
}

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