SILC Atomic operations interface provides utility functions to perform
 simple operations with integers atomically.  This enables fast integer
 additions and subtractions safely in multithreaded environment.  It is
 especially suited for reference counters and similar and is much faster
 than using locking.  This interface supports 8, 16 and 32 bit integers
 and 32 or 64 bit pointers.

 On some platforms this interface actually use mutual exclusion lock
 instead of true atomic operations, leading into some performace penalty.
 Also on some platforms the 8 and 16 bit integers are actually 32 bit
 integers.

 Fast operations are supported on: x86, x86_64, ia64, PPC