Extract and Modify Field in a 32-bit Register

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

uint32_t update_register(uint32_t reg) {
    uint8_t mask = 0x1F;
    uint8_t pos = 10;

    uint8_t field = (reg >> pos) & mask;
    if (field < 31) {
        field++;
    }

    reg &= ~(mask << pos);
    reg |= ((field & mask) << pos);

    return reg;
}

int main() {
    uint32_t reg;
    scanf("%u", &reg);
    uint32_t updated = update_register(reg);
    printf("%u", updated);
    return 0;
}