void Spy(TssStruct *tss)
{
  BoolU4 old_preempt=Preempt(OFF);
  SysHashTable *old_hash=Fs->hash_table;
  Fs->hash_table=tss->hash_table;
  while (!ScanChar) {
    LtfBottom(Fs->cur_ltf);
    PrintF("$$CL$$");
    TssRep(tss);
    StackRep(tss->esp);
    WinSync;
  }
  Fs->hash_table=old_hash;
  Preempt(old_preempt);
}