They are Waiting to see the outcome here Then they will respond.<g>

Regards Art

----- Original Message -----
From: Lawrence Lile <llile@TOASTMASTER.COM>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Tuesday, October 17, 2000 5:12 PM
Subject: Re: [PIC]: Signed Int vs Int


> Well, I can tell you that while we've been discussing this to death for
two
> days on the PIClist, CCS help has *yet* to respond!
>
> -- Lawrence Lile
> ----- Original Message -----
> From: "Andrew Kunz" <akunz@TDIPOWER.COM>
> To: <PICLIST@MITVMA.MIT.EDU>
> Sent: Tuesday, October 17, 2000 8:35 AM
> Subject: Re: Signed Int vs Int
>
>
> > This is one of the reasons I had when I left use of CCS eons ago.
> >
> > Andy
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > Bob Ammerman <RAMMERMAN@PRODIGY.NET> on 10/17/2000 09:13:16 AM
> >
> > Please respond to pic microcontroller discussion list
> <PICLIST@MITVMA.MIT.EDU>
> >
> >
> >
> >
> >
> >
> >
> >
> >  To:      PICLIST@MITVMA.MIT.EDU
> >
> >  cc:      (bcc: Andrew Kunz/TDI_NOTES)
> >
> >
> >
> >  Subject: Re: Signed Int vs Int
> >
> >
> >
> >
> >
> >
> >
> >
> > ----- Original Message -----
> > From: M. Adam Davis <adavis@UBASICS.COM>
> > To: <PICLIST@MITVMA.MIT.EDU>
> > Sent: Tuesday, October 17, 2000 8:40 AM
> > Subject: Re: Signed Int vs Int
> >
> >
> > > Bob Ammerman wrote:
> > > > This is _not_ true.  In ANSI "C", a comparison of an 'int' and an
> > 'unsigned
> > > > int' is performed as a 'unsigned int' comparison, _not_ a 'signed
> long'
> > > > comparison.
> > >
> > > If so, what is the conversion?  You can't represent 250 (or even 128)
in
> a
> > > signed int.  I suppose that there is no conversion, it just refers to
> the
> > uint
> > > as an int, in which case it becomes -6.  <sigh>
> >
> > Yes, there is no conversion. The bits are just reinterpreted as signed.
> >
> > ANSI says an 'int' is at least 16 bits!  If your compiler calls an 8-bit
> > variable an 'int' that is YANAC (yet another non-ansi construct).
> >
> > Actually, ANSI says that _all_ arithmetic is done at at _least_ int
> (16-bit)
> > precision. Not very friendly in the microcontroller world. Compilers can
> do
> > 'char' (8-bit) arithmetic and still call themselves ANSI when the final
> > result of the 8-bit operation is certain to be the same as that in a
> 16-bit
> > operation. For example:
> >
> > unsigned char a;
> > unsigned char b;
> > unsigned char c;
> >
> > c = a + b;
> >
> > The standard says this should be treated as:
> >
> > c = (unsigned char) ( (int) a + (int) b);
> >
> > ie: 'a' and 'b' are promoted to 16-bit signed values and added together.
> The
> > result is then truncated to 8 bits and stashed in 'c'.
> >
> > In this case the compiler _can_ use 8-bit arithmetic because it'll
> _always_
> > come up with the same value for 'c' that it would have obtained with
> 16-bit
> > arithmetic followed by truncation.
> >
> > > Well, this is a reason for good coding practices.  Always cast
variables
> > when
> > > they are dissimilar...  Portability is better then, as well.
> >
> > This is a pretty good idea. Be careful tho' that you don't force your
> > compiler into 16-bit math by casting.
> >
> > > -Adam
> > >
> > > --
> >
> > Bob Ammerman
> > RAm Systems
> > (contract development of high performance, high function, low-level
> > software)
> >
> > --
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