Re: Trying to understand the workings of a Memory Mapped I/O

On Mon, 1 Dec 2003 00:17:44 -0500, Gene S. Berkowitz
<[EMAIL PROTECTED]> wrote in comp.arch.embedded:

> In article <[EMAIL PROTECTED]>, 
> [EMAIL PROTECTED] says...
> > On Sun, 30 Nov 2003 23:07:47 -0500, Gene S. Berkowitz
> > <[EMAIL PROTECTED]> wrote in comp.arch.embedded:
>  
> > > type.  I've had to insert explicit casts exactly like this to get the
> > > compiler to swallow it.
> > 
> > That's absurd.  Any compiler which will not accept this is horribly
> > broken, so much so that it is lying if it claims to be a C compiler at
> > all.
> 
> You can call it whatever you like; it doesn't change the fact that
> tools (I won't call it a C compiler, for your blood pressure),
> especially those sold into the embedded market, are often non-standard
> and/or broken.  I can insert a cast, and the error goes away, or I
> can deliver my code late because I'm spending two hours on the phone
> explaining it to "tech support", then waiting 3 months for the fix.
> 
> --Gene

Are you claiming that you know of a compiler that generates a warning
or error for this:

   unsigned char uc = P0;

...when the P0 macro is defined as:

   #define P0 ((*(__R volatile unsigned char *)0x0))

...but does not when the P0 macro is defined as:

   #define P0 ((*(__R volatile unsigned char *)(unsigned char)0x0))

???

I have sent back alleged C compilers this bad for a refund.  It would
be better to code in assembly than some language that some unqualified
idiot made up.  There is no quality control at all, and you would have
no idea at all of what the code the compiler did accept would actually
do when executed.  If it could bungle something as basic as this, who
knows what object code it would generate from other basic C source
that it misinterprets?

As for compilers for embedded systems, I have been using them for more
than 20 years, for 8 through 32 bit controllers and processors, and
for DSPs as well, so I think I am aware of the state of the market.

-- 
Jack Klein
Home: http://JK-Technology.Com
FAQs for
comp.lang.c http://www.eskimo.com/~scs/C-faq/top.html
comp.lang.c++ http://www.parashift.com/c++-faq-lite/
alt.comp.lang.learn.c-c++ ftp://snurse-l.org/pub/acllc-c++/faq