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Date: Sun, 16 Feb 2003 04:04:47 -0800
From: William Lee Irwin III <wli@holomorphy.com>
To: Falk Hueffner <falk.hueffner@student.uni-tuebingen.de>
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Subject: Re: [PATCH] make jiffies wrap 5 min after boot
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Muli Ben-Yehuda <mulix@mulix.org> writes:
>> I have no idea if that's what wli meant, but -1UL is only "all ones"
>> in a 2's complement binary representation. 

On Sun, Feb 16, 2003 at 12:50:34PM +0100, Falk Hueffner wrote:
> No. Wraparound of unsigned types is well-defined. -1UL must be the
> largest possible unsigned long value, which must consist of only 1
> bits (except for possible padding bits).
> Of course, no machines with ones-complement (or padding bits, or
> integer trap representations, or any of the other ISO braindamages)
> exist, so this is mostly irrelevant anyway.

In the "obvious" sense, -1UL is an oxymoron, as -1 is inherently signed,
and the "UL" says "unsigned".

It's aesthetic. It's a violation of what I consider good taste to
do signed bit twiddling on an unsigned value and/or vice-versa.
Regardless of what ISO and/or Linux may or may not support, the habits
ingrained in me wrt. portability say the assumption must not be made.

YMMV.

-- wli
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