26. Extract and Modify Field in a 32-bit Register

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

uint32_t update_register(uint32_t reg)
{
    uint32_t mask = 0x7C00;   // bits 10–14 (5 bits)
    uint32_t field;

    /* extract field */
    field = (reg >> 10) & 0x1F;

    /* modify field */
    if (field < 31) {
        field++;
    } else {
        return reg;
    }

    /* clear old field bits */
    reg &= ~mask;

    /* insert updated field */
    reg |= (field << 10);

    return reg;
}

int main(void)
{
    uint32_t reg;
    scanf("%u", &reg);

    uint32_t updated = update_register(reg);
    printf("%u", updated);

    return 0;
}