Re: possible powerpc 40x problem in 2.12

[Daniel Jacobowitz <drow at mvista dot com>]

On Thu, Feb 28, 2002 at 05:08:12PM -0600, Joel Sherrill wrote:
> 
> Hi,
> 
> I tried to build all of the RTEMS configurations using
> the same binutils 2.12 source I reported results on 
> earlier and have gotten a failure on the ppc40x targets
> because the following instructions are recognized.  This
> is with gcc 2.95.3 on top of the gas and I think something
> is not quite in sync because -mcpu=403 is resulting in
> -mppc being passed to gas.  With that, it doesn't like
> the mfdcr and mtdcr instructions and claims them as illegal.
> 
> Should I be using a different gcc CPU CFLAG or is
> this a case where binutils 2.12 is intended to be 
> using with gcc 3.x?
> 
> Thanks.

Ugh.  GCC 3.x also passes -mppc in response to -mcpu=403.  I believe
the root of this is the fact that the instruction is assembled
differently on PowerPC and BookE processors (although I can't see
evidence of that in opcodes/ppc-dis.c...).

I believe, if you want to use the 403-specific instructions (which GCC
won't generate) then you need a -Wa,-m403 option (is that the right
one?).  The assembler is generally less permissive about these things.
It may make sense to get GCC patched to pass a different option after
2.12 is released.

Is there a PPC guru in the house?  Am I on track here?


-- 
Daniel Jacobowitz                           Carnegie Mellon University
MontaVista Software                         Debian GNU/Linux Developer