From: jak@rudolph.ccur.com (Joe Korty)
Message-Id: <200212201452.OAA10431@rudolph.ccur.com>
Subject: Re: [PATCH] joydev: fix HZ->millisecond transformation
To: vojtech@suse.cz (Vojtech Pavlik)
Date: Fri, 20 Dec 2002 09:52:28 -0500 (EST)
Cc: george@mvista.com (george anzinger), bjorn_helgaas@hp.com (Bjorn Helgaas),
       marcelo@conectiva.com.br (Marcelo Tosatti),
       linux-kernel@vger.kernel.org
Reply-To: joe.korty@ccur.com (Joe Korty)
In-Reply-To: <20021220142443.A26184@ucw.cz> from "Vojtech Pavlik" at Dec 20, 2002 02:24:43 PM
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[ repost -- I am going to have to get outgoing mail fixed on my lkml-reading
 machine ]

> On Fri, Dec 20, 2002 at 02:41:50AM -0800, george anzinger wrote:
>> Bjorn Helgaas wrote:
>>> 
>>> * fix a problem with HZ->millisecond transformation on
>>>   non-x86 archs (from 2.5 change by vojtech@suse.cz)
>>> [...]
>>> +#define MSECS(t)       (1000 * ((t) / HZ) + 1000 * ((t) % HZ) / HZ)
>>> [...]
> Though it might be easier to say (1000 * t) / HZ, now that I think about
> it.

The more complex version avoids integer overflow for more values of 't'
in the (1000 * t) subexpression.

Joe
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