gistfile1.txt

#include <stdio.h>

static unsigned f(unsigned i) { return i * 40; }

static unsigned setbit(unsigned i, unsigned b) { return i | (1U << b); }

static unsigned clearbit(unsigned i, unsigned b) { return i & ~(1U << b); }

static void testbit(unsigned b) {
  printf("bit %d : ", b);
  unsigned i = 0;
  do {
    unsigned res = f(i);
    if (f(setbit(i, b)) != res || f(clearbit(i, b)) != res) {
      printf("demanded\n");
      return;
    }
    i++;
  } while (i != 0);
  printf("not demanded\n");
}

int main(void) {
  for (unsigned b = 31; b != -1; b--)
    testbit(b);
}