emacs -Q
C-x C-f /tmp/tmp.c  (should be in c-mode)
Copy the following c code and paste it to the new buffer, then emacs 
freezes.

-------------xxxx-----------------
LONG Rounding(
     IN PRTMP_ADAPTER pAd,
     IN LONG Integer,
     IN LONG Fraction,
     IN LONG DenominatorOfTssiRatio)
-------------xxxx---------------