cvs commit: src/sys/sys cdefs.h

[Maxime Henrion]

mux         2003/09/30 13:45:14 PDT

  FreeBSD src repository

  Modified files:
    sys/sys              cdefs.h 
  Log:
  Introduce new __predict_false(exp) and __predict_true(exp) keywords.
  Their purpose is to give explicit hints to the compiler to judge
  the likelyhood of a test to succeed or fail.  Not all architectures
  have support for such optimizations, but for those who do, it can
  give a nice performance improvement in hot loops.
  
  Obviously, this should be used very rarely in very specific code.
  
  Reviewed by:    peter
  Obtained from:  OpenBSD
  
  Revision  Changes    Path
  1.77      +36 -0     src/sys/sys/cdefs.h