From: George Anzinger <george@mvista.com>
To: Tim Bird <tim.bird@am.sony.com>
Cc: Roman Zippel <zippel@linux-m68k.org>,
Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@elte.hu>,
Christopher Friesen <cfriesen@nortel.com>,
linux-kernel@vger.kernel.org, akpm@osdl.org, johnstul@us.ibm.com,
paulmck@us.ibm.com
Subject: Re: [ANNOUNCE] ktimers subsystem
Date: Tue, 27 Sep 2005 13:36:06 -0700 [thread overview]
Message-ID: <4339AD36.2060209@mvista.com> (raw)
In-Reply-To: <4339918C.2040405@am.sony.com>
Tim Bird wrote:
> Roman Zippel wrote:
>
>>On Sun, 25 Sep 2005, Thomas Gleixner wrote:
>>
>>>Can you please point out which architectures do not have a 32x32->64
>>>instruction ?
>
>
> <snip>
>
>>For the rest you might want to check <asm/div64.h>, if div64 has to be
>>emulated, there are good chances this instruction has to be emulated as
>>well (especially in smaller embedded archs).
>
>
> Hmmm. In my experience, there are several embedded platforms
> with a 32x32->64 instruction, which are lacking a div64 instruction.
> I don't think checking for div64 is a very good metric here.
Also, even having a div64 instruction does not eliminate the asm/div64.h
as it checks for results that are >32-bits and does the right thing.
For example, letting the x86 do this divide with such a result, results
in a trap.
This is why we need to be very careful where we use the div_ll_l_rem()
which accesses just this instruction.
--
George Anzinger george@mvista.com
HRT (High-res-timers): http://sourceforge.net/projects/high-res-timers/
next prev parent reply other threads:[~2005-09-27 20:37 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-09-19 16:48 [ANNOUNCE] ktimers subsystem tglx
2005-09-19 16:48 ` [PATCH] " tglx
2005-09-19 21:47 ` [ANNOUNCE] " Thomas Gleixner
2005-09-19 22:03 ` Christoph Lameter
2005-09-19 22:17 ` Thomas Gleixner
2005-09-19 22:24 ` Christoph Lameter
2005-09-19 22:44 ` Thomas Gleixner
2005-09-19 22:50 ` john stultz
2005-09-19 22:58 ` Thomas Gleixner
2005-09-19 23:04 ` Christoph Lameter
2005-09-19 23:12 ` Thomas Gleixner
2005-09-20 7:14 ` Ingo Molnar
2005-09-20 7:10 ` Ingo Molnar
2005-09-21 19:24 ` Pavel Machek
2005-09-19 22:39 ` Christopher Friesen
2005-09-19 22:54 ` Thomas Gleixner
2005-09-20 4:57 ` Christopher Friesen
2005-09-20 5:11 ` Thomas Gleixner
2005-09-20 0:43 ` George Anzinger
2005-09-21 19:50 ` Roman Zippel
2005-09-21 22:41 ` Thomas Gleixner
2005-09-22 12:59 ` Ingo Molnar
2005-09-22 23:09 ` Roman Zippel
2005-09-22 23:31 ` Christopher Friesen
2005-09-23 0:25 ` Roman Zippel
2005-09-23 6:49 ` Thomas Gleixner
2005-09-24 3:15 ` Roman Zippel
2005-09-24 5:16 ` Ingo Molnar
2005-09-24 10:35 ` Roman Zippel
2005-09-24 13:56 ` Thomas Gleixner
2005-09-24 16:51 ` Daniel Walker
2005-09-24 23:45 ` Roman Zippel
2005-09-25 21:00 ` Thomas Gleixner
2005-09-27 16:54 ` Roman Zippel
2005-09-27 19:03 ` Tim Bird
2005-09-28 16:36 ` Roman Zippel
2005-09-25 21:02 ` Thomas Gleixner
2005-09-27 16:48 ` Roman Zippel
2005-09-27 18:38 ` Tim Bird
2005-09-27 20:36 ` George Anzinger [this message]
2005-09-23 2:25 ` john stultz
2005-09-23 8:27 ` Thomas Gleixner
2005-09-24 2:43 ` Roman Zippel
2005-09-24 5:03 ` Ingo Molnar
2005-09-24 9:04 ` James Bruce
2005-09-23 15:21 ` Paul E. McKenney
2005-09-24 3:38 ` Roman Zippel
2005-09-25 15:48 Sid Boyce
2005-09-25 18:20 ` Zwane Mwaikambo
2005-09-26 0:02 ` Sid Boyce
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