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Re: [patch] MIPS/gas: load/store address overflow on binutils 2.14

From: Alan Modra <amodra at bigpond dot net dot au>
To: "Maciej W. Rozycki" <macro at ds2 dot pg dot gda dot pl>
Cc: Thiemo Seufer <ica2_ts at csv dot ica dot uni-stuttgart dot de>,binutils at sources dot redhat dot com, Atsushi Nemoto <anemo at mba dot ocn dot ne dot jp>
Date: Fri, 12 Sep 2003 23:33:02 +0930
Subject: Re: [patch] MIPS/gas: load/store address overflow on binutils 2.14
References: <20030912114308.GA30328@rembrandt.csv.ica.uni-stuttgart.de><Pine.GSO.3.96.1030912150344.17936F-100000@delta.ds2.pg.gda.pl>

On Fri, Sep 12, 2003 at 03:37:22PM +0200, Maciej W. Rozycki wrote:
>     ep->X_add_number = (ep->X_add_number << 32) >> 32;

If I recall correctly, a right shift of a negative signed integer is
"implementation defined" according to the C standard.  You are also
assuming that X_add_number is exactly 64 bit.  Sign extension is
better done with

  x = ((x & 0xffffffff) ^ 0x80000000) - 0x80000000;

-- 
Alan Modra
IBM OzLabs - Linux Technology Centre

Follow-Ups:
- Re: [patch] MIPS/gas: load/store address overflow on binutils 2.14
  - From: Maciej W. Rozycki

References:
- Re: [patch] MIPS/gas: load/store address overflow on binutils 2.14
  - From: Thiemo Seufer
- Re: [patch] MIPS/gas: load/store address overflow on binutils 2.14
  - From: Maciej W. Rozycki

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