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From: Ian Lance Taylor <ian@wasabisystems.com>
To: Christian Groessler <cpg@aladdin.de>
Cc: GCC List <gcc@gcc.gnu.org>
Subject: Re: signed/unsigned right shift
References: <87vfl7s3lf.fsf@aladdin.de>
Date: Sun, 14 Mar 2004 18:23:00 -0000
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Christian Groessler <cpg@aladdin.de> writes:

> >Correct, the multiplication is done as signed int.  And it is
> >implementation
> >defined whether right shift of a negative signed int does sign fill or
> >not.
> >So both compilers are right; it is only your code that's wrong.
> >
> >C89 references: 3.3.7, 3.2.1.5, 3.2.1.1.
> 
> Hmm, unfortunately I don't have the c89 standard document. Can
> somebody point me to the equvalent sections in c99?

Usual arithmetic conversions performed on operands of multiplication:
6.5.5.

Usual arithmetic conversions: 6.3.1.8.  Note in particular "the
integer promotions are performed on both operands."

Integer promotions: 6.3.1.1.

Right shift of signed negative value implementation defined: 6.5.7.

Ian