RTEMS Logo

RTEMS 4.10.1 On-Line Library


Timer Driver Read_timer

PREV UP NEXT Bookshelf BSP and Device Driver Development Guide

10.1.2: Read_timer

The benchmark_timer_read routine returns the number of benchmark time units (typically microseconds) that have elapsed since the last call to benchmark_timer_initialize.

int benchmark_timer_read(void)
{
  stop time = read the hardware timer
  if the subtract overhead feature is enabled
    subtract overhead from stop time
  return the stop time
}

Many implementations of this routine subtract the overhead required to initialize and read the benchmark timer. This makes the times reported more accurate.

Some implementations report 0 if the harware timer value change is sufficiently small. This is intended to indicate that the execution time is below the resolution of the timer.


PREV UP NEXT Bookshelf BSP and Device Driver Development Guide

Copyright © 1988-2008 OAR Corporation