[ColdFire 9/63] Add -mcpu, -march, -mtune, and related options

Jeffrey Law law@redhat.com
Wed Jan 10 18:22:00 GMT 2007

On Wed, 2007-01-10 at 10:54 +0000, Richard Sandiford wrote:

> An obvious implication is that -m68020 should be orthogonal to the
> FPU selection, but the other architecture options shouldn't be.
> However, I don't that's necessarily the reason why the code is
> the way it is, because...
I have no idea why it was done that way.   It's never been terribly
rational, though the irrationality is easier to see with the removal
of the FPA support a few years ago.

>   The m68k-* configurations all default to hard-float 68020, and if
>   you pass -m68020 to the m68k-* gccs, you still get hard-float code.
>   The only configuration for which the special treatment of -m68020 makes
>   a difference _in isolation_ is m68010-*-netbsdelf, which continues to
>   generate soft-float code when passed -m68020.  However, I doubt that
>   the netbsd effect was a deliberate decision.  It seems more logical
>   for "m68010-*-netbsdelf-gcc -m68020" to generate the same code as
>   m68k-*-netbsdelf-gcc, which is the equivalent 68020 configuration,
>   and which defaults to hard-float code.
Agreed (it probably wasn't a deliberate decision).  Particularly if they
used my ancient 68010 HPBSD support as a template for netbsdelf
(netbsdelf is a descendent of the HPBSD code on numerous levels).


ps.  I'm just going to blindly trust that you've got all the ColdFire
variants right -- you're *far* more familiar with them than I am.

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