#include <stdio.h>

/* Define some bits to represent various flags */
#define BIT_USED  (1U << 0)
#define BIT_FREE  (1U << 1)
#define BIT_TAINT (1U << 2)
#define BIT_DIRTY (1U << 3)

/* Modifies in-place */
#define BIT_SET_NTH(N, K)    (N |= (1 << (K - 1)));
#define BIT_CLEAR_NTH(N, K)  (N &= (~(1 << (K - 1))))
#define BIT_TOGGLE_NTH(N, K) (N ^= (1 << (K - 1)))
#define BIT_TEST_NTH(N, K)   (N & (1 << (K - 1)))

#define BIT_SET(N, K)    (N |= (K))
#define BIT_CLEAR(N, K)  (N &= ~(K))
#define BIT_TOGGLE(N, K) (N ^= (K))
#define BIT_TEST(N, K)   (N & K)

int main(void) {
    char flags = 0;

    /* Set a set of flags */
    flags |= BIT_USED | BIT_TAINT;
    printf("Flags: %.8b\n", flags);

    /* Unset a set of flags */
    flags &= ~BIT_USED;
    printf("Flags: %.8b\n", flags);

    /* Toggle a bit */
    flags ^= BIT_USED;
    printf("Flags: %.8b\n", flags);

    if (flags & BIT_USED)
        printf("Bit is used!\n");

    /* Clear all bits except */
    flags &= BIT_USED;
    printf("Flags: %.8b\n", flags);

    /* Wipe flags */
    flags = 0;

    BIT_TOGGLE(flags, BIT_USED);
    printf("Flags: %.8b\n", flags);

    BIT_SET(flags, BIT_DIRTY | BIT_TAINT);
    printf("Flags: %.8b\n", flags);

    if (BIT_TEST(flags, BIT_DIRTY))
        printf("Bit is dirty!\n");

    BIT_CLEAR(flags, BIT_DIRTY | BIT_USED | BIT_TAINT);
    printf("Flags: %.8b\n", flags);
}