[RTEMS Project] #3456: Add support for CPU counter timestamps

[RTEMS trac]

#3456: Add support for CPU counter timestamps
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 Reporter:  Sebastian Huber  |       Owner:  Sebastian Huber
     Type:  enhancement      |      Status:  assigned
 Priority:  normal           |   Milestone:  5.1
Component:  score            |     Version:  5
 Severity:  normal           |  Resolution:
 Keywords:                   |  Blocked By:
 Blocking:                   |
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Comment (by Sebastian Huber <sebastian.huber@…>):

 In [changeset:"0a1f5df98e52b028bf8b4de3bf63e39702fa5f34/rtems"
 0a1f5df9/rtems]:
 {{{
 #!CommitTicketReference repository="rtems"
 revision="0a1f5df98e52b028bf8b4de3bf63e39702fa5f34"
 Simplify _CPU_Counter_difference()

 In order to simplify the use of CPU counter values it is beneficial to
 have monotonic increasing values within the range of the CPU counter
 ticks data type, e.g. 32-bit unsigned integer.  This eases the use of
 CPU counter timestamps in external tools which do not know the details
 of the CPU counter hardware.  The CPU counter is the fastest way to get
 a time on an RTEMS system.

 Such a CPU counter may be also used as the timecounter.  Use it on SPARC
 for this purpose to simplify the clock drivers.

 Update #3456.
 }}}

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Ticket URL: <http://devel.rtems.org/ticket/3456#comment:6>
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