Re: REGISTER_PREFIX in egcs 1.0.2

[Joel Sherrill <joel@OARcorp.com>]

On Sun, 3 May 1998, Jeffrey A Law wrote:

>   > 
>   > This would be easy to add to all the configurations if one had the right
>   > knowledge. How would be the safest way to go about adding these to make
>   > sure they are correct?
> I'm not 100% sure I understand what you're asking for.

I would like to eventually see at least USER_LABEL_PREFIX and
REGISTER_PREFIX available and correct on all ports.

> Are you asking for all the ports to actually use REGISTER_PREFIX
> and friends?  This would be a lot of work, and I doubt it's worth
> the effort since few ports need this facility.

I agree that it is not a pressing need.  I think this is something which
could be fixed as it is needed.

> Or are you asking that REGISTER_PREFIX and friends always be available 
> for use by assembly code fed through gcc/cpp?  

I am asking exactly this.  

> It looks like we try
> to always make them available (defaulting their value to "" if the
> target doesn't provide a definition).

The problem for me right now if that this is not always correct.

In the i386 asm.h we have in RTEMS, I have to undef __REGISTER_PREFIX__
from "" to set it to %.  This generates a warning every time our asm.h is
used.  I was on a warning elimination sweep and was going to fix this in
config/i386 when I realized that I did not know what it should be on EVERY
i386 target so was unsure what was correct. 

I would be happy to add these correctly to every CPU that has an RTEMS
port (so I can test them), if I had any confidence I was not going to
break something for another target.  Doing anything general in the i386
directory is scary given the number of users on that port. :) 

I think REGISTER_PREFIX should be % for for at least i386-coff and
i386-rtems.  It probably should be % for i386 elf configurations as well. 
I also have a note that in our asm.h that USER_LABEL_PREFIX is broken for
go32 but have not verified that recently. 

Any suggestions on how to get at least the i386 right without fear 
of breaking anything else?

--joel