busy.c

#include <stdio.h>
#include <stdlib.h>

int main(int argc, char *argv[]) {
  unsigned int i;
  unsigned int x = 0xdeadbeef;
  if (argc==2) 
    x = atoi(argv[1]);
  printf("seed value: %x\n", x);

  /* long-running computation */
  for (i=0; i<1<<30; i++) {
    x ^= x << 13;
    x ^= x >> 17;
    x ^= x << 5;
  }
  printf("busy computing %x\n\n", x);
  return 0;
}