If you're using a Pentium-class machine, then a nice trick is to wrap
the RDTSC assembly instruction and call that. It returns number of
clock cycles elapsed (a 64 bit number IIRC). Here's some code to get
you started:

#ifdef linux
#include <sys/bitypes.h>
#endif

extern inline u_int64_t
rdtsc (void)
{
  u_int32_t hi, lo;
#ifdef linux
  __asm__ ("rdtsc" : "=d" (hi),  "=a" (lo));
#else
  __asm__ (".byte 0x0f,0x31" : "=d" (hi),  "=a" (lo));
#endif
  return ((u_int64_t) hi) << 32 | lo;
}

Rich.

-- 
Richard Jones. http://www.annexia.org/ http://freshmeat.net/users/rwmj
Merjis Ltd. http://www.merjis.com/ - improving website return on investment
"My karma ran over your dogma"

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