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Re: Overflow fix (was Problems with trampoline.S with 64 bit binutils)


   Date: Thu, 29 Jul 1999 08:27:32 +0930 (CST)
   From: Alan Modra <alan@SPRI.Levels.UniSA.Edu.Au>

   On 28 Jul 1999, Ian Lance Taylor wrote:

   >    Date: Wed, 28 Jul 1999 18:39:18 +0930 (CST)
   >    From: Alan Modra <alan@SPRI.Levels.UniSA.Edu.Au>
   > 
   >    Is it OK for me to check this one in, Ian?  It's almost in the "obvious
   >    fix" category...
   > 
   > Almost.
   > 
   >    > +	      mask <<= size * 8 - (fixP->fx_signed ? 1 : 0);
   > 
   > If size is 4 and fixP->fx_signed is not set, then this will do a left
   > shift by 32.  If mask is itself 32 bits, then this is not defined by
   > ANSI C.  There are in fact compilers which will turn this into a
   > no-op: they generate a shift by 32 instruction, which is masked into a
   > shift by 0 instruction.
   > 
   > That's why I had the two shifts in the old code, and I think we need
   > to keep that.

   size == 4  =>  sizeof (mask) > 4.  Surely ANSI C doesn't restrict shift
   counts of 64 bit quantities to 32??

Whoops, sorry, I totally missed the initial if condition.  Yes, please
check in this patch.

Ian

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