Re: [PATCH] Fix CPU bitmask truncation

From: Andreas Schwab (schwab@suse.de)
Date: Fri Dec 20 2002 - 15:00:23 EST

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Jeremy Fitzhardinge <jeremy@goop.org> writes:

|> On Fri, 2002-12-20 at 04:17, Andreas Schwab wrote:
|> > This is useless. Assigning -1 to any unsigned type is garanteed to give
|> > you all bits one, and with two's complement this also holds for any signed
|> > type.
|>
|> Only if the -1 is the same size as the unsigned type. Otherwise it will
|> be 0-extended.

Wrong. Unsigned arithmetics is defined as modulo MAX+1, and -1 equals MAX
modulo MAX+1 for every MAX.

Andreas.

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Andreas Schwab, SuSE Labs, schwab@suse.de
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