RE: [Sdcc-user] calculation with long variables

[<MSoegtrop@Michael-Soegtrop.de>]

Dear Mathias,

i had a similar effect with 2.3.1. It worked to switch loop invariant
optimization off (option -=96noinvariant). I have prepared a bug report
for this last week, where you can clearly see in the assemley dump that
a register where a loop invariant expression is stored is overwritten
somewhere. Sorry for not sending this in yet, but i moved with my lab
and don't have my network up there yet. If this bug is not yet known, i
promise to send the bug report asap.

Best regards,

Michael

> -----Original Message-----
> From: sdc...@li...
> [mailto:sdc...@li...]On Behalf Of Matthias
> Wei=DFer
> Sent: Wednesday, May 29, 2002 4:30 PM
> To: Bernhard Held
> Cc: sdc...@so...
> Subject: Re: [Sdcc-user] calculation with long variables
>
>
> > > xdata unsigned char idebuf[8192];
> > > unsigned char j =3D 0;
> > > ...
> > >     uc_strcpy(&idebuf[(i-32+1)-j*32],&lfn[j*13],5);
> > >     uc_strcpy(&idebuf[(i-32+14)-j*32],&lfn[(j*13)+5],6);
> > >     uc_strcpy(&idebuf[(i-32+28)-j*32],&lfn[(j*13)+11],2);
> > >
> > >     if ((idebuf[(i-32-j*32)] & 0x40) =3D=3D 0x40) break;
> >
> > j*32 is calculated as 8x8 bit multiplication and will overflow very
> quickly.
> > You will only get correct results in the range 0 <=3D j <=3D 7. Fix:
> >     ...   - (unsigned) j * 32] ...
>                      ^^^^^^
> i expect this should be a (unsigned int)?
>
> > Tell me, if this doesn't help.
>
> The Problem is that the calcultion fails even when j =3D 1
>
>
> Matthias Wei=DFer
> mat...@ma...
> http://www.matwei.de
>
>
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