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tmr.h File Reference

Provides a set of timing macros. More...

#include "tmr.h.xx-xxx-xxx"

Functions
int	TMR_initialize (void)
	Initializes the TMR facility. More...
TMR_tick	TMR_nsecs_to_ticks (int nanoseconds)
	Convert a number of nanoseconds to PTUs. More...
unsigned int	TMR_ticks_to_nsecs (TMR_tick ticks)
	Convert a number of ticks to nanoseconds. More...
unsigned int	TMR_frequency (void)
	Get the frequency of the processor timer. More...

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Detailed Description

Provides a set of timing macros.

Author:

JJRussell - russell@slac.stanford.edu

\bABSTRACT
--------
This implements a facility to time accurately short duration events. The implementation is platform dependent, seeking to use the highest resolution clock that is available. The facility provides a uniform and consistent compile time interface. Note that this is not the same as a uniform and consistent run time interface. In particular the timer units may vary platform to platform. This difference is taken out by a typedef of the TMR units (TMR_ticks). The resolution is also platform dependent, so a function to convert process timer units to NSECS is provided.

Finally, to keep the overhead low, consistent with timing short duration events, certain compromises where made. In general, do not use this facility to time events > 200 secs. The normal system clocks should be used instead.

\bEXAMPLE
-------

  
    TMR_tick     beg;
    TMR_tick     end;
    TMR_tick elapsed;
  
    beg     = TMR_GET();
    .
    eventToTime ();
    .
    end     = TMR_GET();
    elapsed = end - beg;
  
    printf ("Begin   Time: " TMR_FORMAT "tickss\n", beg);
    printf ("End     Time: " TMR_FORMAT "ticks\n", end);
    printf ("Elasped Time: " TMR_FORMAT "tickss\n", elapsed);
    printf ("Elasped Time: " TMR_FORMAT "ticks\n",
                             TMR_TO_NSECS (elapsed);
  

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Function Documentation

unsigned int TMR_frequency (  void    )

Get the frequency of the processor timer. Returns: The frequency, in Hertz, to the processor timer

int TMR_initialize (  void    )

Initializes the TMR facility. This is a one time only call to initialize internal data structures. This routine should be called as part of the library initialization sequence.

int TMR_nsecs_to_ticks (  int    nanoseconds )

Convert a number of nanoseconds to PTUs. Parameters: nanoseconds  The number of nanoseconds to convert to PTUs Returns: The number of equivalent PTUs

unsigned int TMR_ticks_to_nsecs (  TMR_tick    ticks )

Convert a number of ticks to nanoseconds. Parameters: ticks  The number of ticks to convert to nanoseconds Returns: The number of equivalent nanoseconds

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