From: Graeme Russ <graeme.russ@gmail.com>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH] arm: add 64-64 bit divider
Date: Tue, 20 Sep 2011 21:40:19 +1000 [thread overview]
Message-ID: <4E787BA3.4030606@gmail.com> (raw)
In-Reply-To: <20110920112842.DFB301407969@gemini.denx.de>
On 20/09/11 21:28, Wolfgang Denk wrote:
> Dear Graeme Russ,
>
> In message <4E786EBA.5040805@gmail.com> you wrote:
>>
>> You'll laugh at this - the Intel High Performance Event Timers (HPET) are
>> defined to a resolution of femto-seconds and you end up with code in
>> get_timer() like:
>
> I have to admit that I have never been able to laugh about x86 design
> issues. But then, Intel told us the Pentium would have "RISK"
> features...
*ROFL*
Well actually, it's not really an x86 thing - Any architecture could
implement HPET. Using femto-seconds as the time-base and defining a 'tick'
as a number of femto-seconds makes a lot of sense - It allows preservation
of timer accuracy through the comparators so interrupts can be generated
with extreme precision while actually allowing the source clock to be
pretty much any frequency. They were, after all, designed for multi-media
applications to solve the horrendous sub-ms accuracy issue with the older
programmable timers
Regards,
Graeme
prev parent reply other threads:[~2011-09-20 11:40 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-31 10:38 [U-Boot] [PATCH] arm: add 64-64 bit divider Che-Liang Chiou
2011-08-31 11:56 ` Marek Vasut
2011-08-31 14:32 ` Mike Frysinger
2011-08-31 15:11 ` Marek Vasut
2011-08-31 15:27 ` Mike Frysinger
2011-08-31 15:33 ` Marek Vasut
2011-08-31 16:05 ` Mike Frysinger
2011-08-31 16:30 ` Marek Vasut
2011-08-31 17:13 ` Mike Frysinger
2011-08-31 20:03 ` Wolfgang Denk
2011-09-01 10:09 ` Che-liang Chiou
2011-09-01 10:16 ` Marek Vasut
2011-09-01 10:30 ` Che-liang Chiou
2011-09-01 10:42 ` Marek Vasut
2011-09-01 12:06 ` Che-liang Chiou
2011-09-01 13:07 ` Wolfgang Denk
2011-09-02 3:12 ` Che-liang Chiou
2011-09-07 21:14 ` Wolfgang Denk
2011-09-20 10:45 ` Graeme Russ
2011-09-20 11:28 ` Wolfgang Denk
2011-09-20 11:40 ` Graeme Russ [this message]
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